Returning Sea Otters to the Oregon Coast

Understanding the role of sea otters as a keystone species in marine nearshore environments provides an excellent example of species interconnections. In this post we’ll wade on into the coastal waters of Oregon and take a look at how a healthy kelp forest works to maintain a balance of the marine nearshore ecosystem, the role of the southern sea otter (Enhydra lutris nereis), the rise in what is called “urchin barrens”, and current efforts to reintroduce sea otters to the Oregon coast.

History

It’s estimated that between 16,000 and 17,000 southern sea otters once lived in the waters along the Pacific coast. By the early 1900’s, sea otters were hunted to near extinction by fur traders and commercial fishermen who thought the otters were competing with them for shellfish (see previous post Beaver: The Ultimate Keystone Species). The number of sea otters off the central coast of California was at a low of about 50 in 1938. The last sea otter in Oregon was killed in 1906, and in Washington in 1910. In 1969-1970, the U.S. government was planning to perform nuclear testing at Amchitka Island in Alaska. Thankfully, marine biologists working there at the time intervened and facilitated the moving of 59 sea otters from Amchitka Island to the northern coast of Washington prior to the blast taking place. Thousands of sea birds and about one thousand sea otters died in that nuclear blast. The relocated population of 59 otters has grown to 2,962 (in 2019) and is now mixing with another sea otter population in Vancouver, B.C. as well as expanding their range south. The southern sea otter is currently federally listed as a threatened species. Oregon is the only state where sea otters once lived that remains unpopulated.

Key Players in an Ideal Sea Otter Habitat

Sea Otters

The sea otter is both the heaviest member of the weasel family and one of the smallest marine mammals. They do not have an insulating blubber layer like other marine mammals yet they live in an environment where the ambient temperature is about half their body temperature. They maintain their body temperature with the aid of their very thick fur, and by eating a lot. Their fur is the thickest of all animals in the animal kingdom with one billion hairs per square inch! They groom their fur constantly which allows a layer of air next to their skin, effectively creating a dry suit for themselves. They weigh up to 100 pounds and, in the wild, generally live to be 14 – 17 years old.

Sea Otters are highly social animals and live together in groups called “rafts”. A raft will consist of either all females with one or two males that mate with these females or a group of bachelor males. Otter pups are dependent on their mother for 5-6 months after birth. Pregnancy and caring for pups are a huge energy burden on the female and their health can suffer as a result. Their diet consists of marine invertebrates (sea urchins, mollusks, crustaceans) and some species of fish. They use rocks to pry invertebrates off the sea floor and pound them open them making it one of the few mammal species to use tools.

A favorite meal of the sea otters is sea urchins. The sea urchin’s favorite meal is kelp. In some areas such as the Alaskan coast, the relationship between sea otters present and kelp forest abundance is starkly apparent; when sea otters are present in an ecosystem the urchin population remains under control which, in turn, allows kelp forests to grow. When sea otters are absent we see urchin populations multiply and kelp forests severely degraded or missing altogether. This environment is called an “urchin barren” and reflects an ecosystem out of balance, but keep in mind that the variables that lead to an urchin barren state are numerous, making this a complex issue.

Kelp Forests

Giant kelp forests in the nearshore marine environment are considered highly productive and highly diverse ecosystems. Kelp are large brown algae that form in shallow, cold, nutrient-rich waters off the coast. Kelp forests are found around the world with the Pacific Northwest coast being particularly well-suited for them. The largest species off the Oregon coast is bull kelp (Nereoctstis leutkeana). Both annual and perennial species of kelp exist; perennial species can live up to 20 years. Seaweeds are anchored on the sea floor and have long blades that can grow up to 18 inches per day. These blades grow straight to the waters surface, staying aloft by a gas-filled bladder at the base of each blade. Kelp are photosynthesizers that play a role at the base of the food chain. On decomposing, they enrich the ocean water with nutrients which are then utilized by filter feeders (muscles, barnacles, etc) and other invertebrates. They modify light levels and help control sedimentation, reduce erosion by blunting the force of incoming waves, and provide a significant amount of carbon sequestration. They are biodiversity hotspots and serve as a nursery for many species including many types of invertebrates, juvenile rockfish, seals, sea lions, whales, sea otters, gulls, terns, snowy egrets, great blue herons, and other shore birds. To thrive, kelp need only light for photosynthesis and abundant nutrients, typically coming from the upwelling of deep ocean cold water.

Historically, kelp forests have occupied about 25% of the world’s coastlines. Unfortunately, kelp forests in the Pacific Northwest are now in decline due to climate change, sea star wasting disease, urchin population explosion, and the absence of sea otters. The unhealthy corollary to a healthy kelp forest is a referred to as a sea urchin barren. There are some areas off the Southern California coast where kelp forests thrive without sea otters being present. However there urchin populations are kept in control by the presence of other predators, including lobsters and California sheepshead. If these predators are removed from the ecosystem (through over-fishing or by other factors) it will again allow urchins to thrive and the kelp forest to degrade. Other species that feed on kelp such as sea stars, isopods, kelp crabs, and herbivorous fishes tend to feed on drift kelp — kelp that has been dislodged from its substrate. When sufficient drift kelp is available, these species do not impact the attached kelp plants. Currently, 50% of the kelp beds in Oregon are found at the Port Orford reef in southern Oregon.

Sea Urchins

28 Jul 2011, Channel Islands National Marine Sanctuary, California, USA — California, Channel Islands. Giant red urchins, Strongylocentrotus franciscanus, and purple urchins crowd the top of a rock. Urchins are havested commercially for their roe (eggs). — Image by © Ralph Clevenger/Corbis

There are two types of sea urchins: red (Mesocentrotus franciscanus) and purple (Strongylocentrotus purpuratus). The larger red urchins are the ones being fished for marketing of the uni (gonads). Red urchins commonly live over 30 years and can live up to 200 years. They are not always successful at reproducing as conditions have to be just right; some years will result in a boom of red urchin larvae, others not. Red urchins mainly eat drift kelp. The red urchin population was fished out along the west coast in the 1990’s but with protections are making a comeback. They are managed as a fishery product.

Purple urchins live in shallower sub-tidal zones but as their populations explode they move into the zone where red urchins are found. Purple urchins will feed on the base of the living kelp plant causing the plant to die. When urchins have eaten all the food available in their area and created an “urchin barren”, they starve but they don’t die; they go into a state of low metabolic activity and can survive for years in this state. Starved out sea urchins do not produce uni, which is what sea otters feed on. Sea stars also feed on purple sea urchins. Interestingly, the urchins will part their spines and allow an approaching sea start to get close to them before launching a surprise attack; the urchin uses its pinchers to gnaw on the sea star’s tube feet causing the sea star to back away. However, sunflower sea stars are unaffected by this attack and will continue advancing to eat the urchin whole — spines and all!

Sea Stars

Sea stars are a large and diverse class of Echinoderrms with over 1,900 living species. There are 11 species that are typically found on Oregon’s coast including the Pacific blood star (Henricia leviuscula), the Sunflower sea star (Pycnopodia helianthoides), and the purple or ochre star (Pisaster ochraceus) typically seen in tidal pools. Sea stars are highly adapted, mobile creatures that have few natural enemies.

Together, sunflower sea stars and sea otters can control sea urchin populations by preying on them. In the ecology world, this is known as functional redundancy — the idea that when two or more species in an ecosystem community perform similar functions, there should be a buffering effect that protects against the loss of either species.

In 2013 – 2014, multiple species of sea stars began dying off in huge numbers — up to 90% of species were lost on the Pacific Northwest coast. Scientists have identified the virus responsible for the disease as a single virus — sea star associated densovirus (SSaDV) — yet it remains unclear what environmental factors caused this outbreak to be so severe. Basically, the sea stars outer layer (the “skin”) melts away allowing their bodies to deteriorate. This event, dubbed “Sea Star Wasting Disease” (SSWD), began in Howe Sound just north of Vancouver, British Columbia and killed all of the sunflower sea stars along with 20 other species of sea stars. The scale and speed of this event was shocking. Howe Sound appears to have been ground zero for this event, but SSWD quickly spread along the entire west coast of the Pacific. Recovery of the sea stars since then has been uneven. Some species seem to have bounced back, but there was 100% loss of sunflower sea stars in the PNW (except for a small population in the Puget Sound area), and they are not coming back. At many locations, urchin populations have exploded and created urchin barrens. Note that echinoderms, in general, experience boom-bust cycles and may take decades to return to an area previously inhabited (if at all).

Some of the Challenges to Marine Nearshore Environments

The kelp forests of the Pacific Northwest have been in moderate decline for many years and the problem is growing worse. Even more severe declines have been documented elsewhere in the world. Ocean kelp forests can be seen from space using the Landsat satellites. Scientists can use this data to document the changes to kelp forests over time. This method is being used in Oregon.

In 2013 – 2015, a heat wave formed in the Pacific Ocean off the coast of North America. It was officially termed “the blob”. The warm waters of the blob were nutrient-poor and extremely hard on kelp forests. In northern California, there was a 90% loss of kelp forests and sea stars attributed to this event. To date, the kelp has not come back and there has been a huge increase in the number of sea urchins as well as an increase in the mussel population. Efforts are underway to reintroduce sea otters and sea stars to help restore the kelp forests. The kelp forests off the Oregon coast were not as severely affected by the blob. The dynamics of these ecosystems are very complex and not well understood. Scientists are monitoring many different areas to try to better understand what is driving kelp decline. Recent studies have shown that kelp forests can thrive in deeper oceanic zones of the warmer, tropical waters where light can penetrate to greater depths. The growth of kelp is not affected as much by water temperature as it is by nutrient availability, particularly nitrogen. Under conditions of adequate light and nutrients, kelp can thrive in water temperatures of up to 23ºC.

One of the ecosystem threats that has been associated with climate change is an increase in domoic acid (DA) intoxication. DA is a potent neurotoxin produced by a diatom species (genus Pseudo-nitzschia) that can accumulate in the food web. This diatom is found worldwide and has the greatest impact on oceanic eastern boundary upwelling systems, which includes the west coast of the U.S. DA toxicity is an important cause of marine wildlife mortality as well as a threat to human food safety. DA enters secondary trophic levels of a food web when suspension feeds such as shellfish and anchovies ingest the toxic diatom cells. High DA levels have been shown to be associated with warmer ocean temperatures and are associated with both the Pacific Decadal Oscillation (PDO) and El Niño events, particularly when these two conditions coincide. If these warm ocean events become more persistant due to global warming, West Coast DA events may also increase. Due to their small body size, high metabolism, and diverse prey preferences sea otters are particularly susceptible to DA exposure. In one study that reviewed findings for southern sea otter necropsies of 560 animals over a 15 year period, probable DA intoxication was a primary or contributing cause of death for 20% of the sea otters.

Ocean acidification is a whole topic unto itself but I want to give it a quick mention in this section. Ocean acidification refers to a reduction of the ocean pH over an extended period of time, caused primarily by the uptake of carbon dioxide (CO2) from the atmosphere. When CO2 is absorbed by seawater, a series of chemical reactions occur resulting in an increased concentration of hydrogen ions. This increase causes seawater to become acidic and reduces the availability of carbonate ions necessary for the building of sea shells and coral skeletons. Sea urchins, corals, oysters, diatoms, and other organisms with shells or skeletons end up with very thin shells and skeletons and ultimately the entire oceanic food web is at risk of collapsing.

So far, ocean pH has dropped from 8.2 to 8.1 since the industrial revolution, and is expected by fall another 0.3 to 0.4 pH units by the end of the century. A drop in pH of 0.1 might not seem like a lot, but the pH scale, like the Richter scale for measuring earthquakes, is logarithmic. For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6. If we continue to add carbon dioxide at current rates, seawater pH may drop another 120 percent by the end of this century, to 7.8 or 7.7, creating an ocean more acidic than any seen for the past 20 million years or more.

How well marine organisms will adapt to a rapidly changing environment due to climate change is not well understood. An evolutionary perspective is necessary to better understand climate change effects on our seas and to examine approaches that may be useful for addressing this challenge.

Feasibility of Sea Otter Reintroduction in Oregon

Efforts are underway to return sea otters to the southern Oregon coast. This section of the coast has a rocky surface that can support the players’ necessary for a successful return of sea otters to the environment. The state of the current environment here is degraded and will need some restoration work upfront to help ensure the success of sea otter reintroduction. The Elakaha Alliance is working with a number of cross-disciplinary groups and researchers to first target restoration work in certain areas (culling purple urchins, nurturing kelp oasis’).

The Elakaha Alliance recently completed an in-depth scientific study to assess the feasibility of reintroducing sea otters to the Oregon Coast. Here are their five main takeaways:

  1. Reintroductions (through translocation) are a successful conservation tool. Previous reintroductions into southeast Alaska, British Columbia, and Washington have increased species viability, helped recover genetic diversity, and improved gene flow in sea otter populations.
  2. Reintroducing sea otters to Oregon is likely to succeed, with appropriate considerations. A model developed specifically for evaluating population success of reintroductions in Oregon suggest that several areas, mostly along the southern coast, would likely support a successful reintroduction of sufficient numbers of otters. The model also indicates that multiple release locations may be more effective than a single release site.
  3. Estuaries may be an important reintroduction environment, especially when close to a suitable nearshore ocean habitat. These environments support sea otter populations in some areas of California. Further research is recommended to review potential sea otter – human interactions in estuaries, however otters could potentially move into estuaries and sloughs as populations recover.
  4. Return of sea otters will have many direct and indirect effects. As a keystone species, sea otters have inordinately strong effects on the nearshore ecosystems they inhabit. Indirect ecosystem enhancements include: increases in kelp forest and eelgrass beds which, in turn, increase fin fish and invertebrate species, increase in overall biodiversity and productivity, increase in carbon capture and fixation. Sea otter reintroduction can also have a negative social and economic impact on the shellfish industry.
  5. Social, economic factors and regulatory issues must be considered. Reintroductions can only occur if these issues are fully addressed. Outreach and engagement with a broad array of affected stakeholders are essential.

Elakha Alliance is currently working on its second of three phases — achieving consensus of key partners including tribes, shellfish harvesters, fisherman, ports, businesses, conservation organizations, and local, state, and federal governments. This phase is expected to conclude no earlier than 2024. The final phase will be to restore a viable, sustainable population of sea otters to a few select places along the Oregon coast. This is expected to take from 2-4 years before actual restoration begins, followed by monitoring, research, and continued stakeholder engagement. Experience and the models show that, following reintroduction of sea otters to a new environment is typically followed by a significant loss of the animals immediately, followed by a slow rebound of several years, then a more rapid increase in population. So, it will be several more years before we will be able to watch sea otters off our Oregon coast, but what a delight that will be!

Making the Connection

My position on restoration work has shifted over the past several years since I was first studying to become an Oregon Master Naturalist. I used to believe that Mother Nature was best left alone to recover from human disturbance in the way that only she knows how to do best. This conviction was borne out of the belief that, in many cases, when humans try to “restore” an area to a more “natural” state they quite often fail or make things worse simply because they don’t have a full understanding of all the relationships and interconnections between species and the environment. I have much more respect for someone who is considered an expert in their field if they freely acknowledge how much they still have to learn about their field. Amazing discoveries continue to be made daily in the scientific world — sometimes blowing long-held beliefs out of the water — and will continue to be made into the future. The complexity of Earth’s ecosystems is simply mind-blowing, when you have even a small glimpse into the finely-tuned workings of Mother Nature you are humbled and awe-struck.

I have come to understand that, in many cases, restoration work is not only necessary but vital in assisting Mother Nature in the recovery of human-disturbed complex ecosystems. The work of The Elakha Alliance is an excellent example of how this work can be done successfully; with intensive study and engagement with known experts in all the identified fields related to the restoration work, with the understanding that the work will take many years to complete, with the humbleness to acknowledge that, while we know a lot about this environment, there are things we do not know that may affect the outcome but we are going to give this our best shot.

I encourage you to watch this excellent 7-minute video made by KQED and Quest titled Sea Otters v. Climate Changehttps://www.kqed.org/quest/65409/sea-otters-urchins-kelp-climate-change

References Cited

The Drastic Decline of Creepy Crawlies and Winged Wonders

The insects of the world are incredibly numerous, diverse, critical to the web of life, and disappearing in alarming numbers. In my last post I mentioned the concept of shifting baselines syndrome and gave my own observational example of how, when I was much younger, I recalled the numerous bug splats on your car windshield that needed to be cleaned off every time you filled the gas tank, yet now it is rare to even get a single bug splat on your windshield. While doing research for this post, I found that this is a well-known observation and has been dubbed “the windshield effect”. In this post, I would like to explore this further and provide some insights on why we need to care about and protect the insect world. It’s a huge topic but I will work to keep it digestible by providing some specific examples.

If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos. — E. O. Wilson

DEFINITIONS

  • Biotic homogenization: The process by which ecosystems lose their biological uniqueness. This is an emerging, yet pervasive, threat in the ongoing biodiversity crisis. This phenomenon stems primarily from two sources: extinctions of native species and invasion of nonnative species. While this process pre-dates human civilization, as evidenced by the fossil record, and still occurs due to natural impacts, it has recently been accelerated due human-caused pressures.
  • Taxonomy: a hierarchical scheme of classification in which things are organized into groups or types based on shared characteristics. Today we still use an expanded version of the system developed by Carl Linnaeus in the 18th century. The categories, from broadest to most specific, are: Domain – Kingdom – Phylum – Class – Order – Family – Genus – Species.
  • Neonicotinoid pesticides: a class of chemical insecticides that act by causing neurotoxic effects on nicotinic acetylcholine receptors in the nerve synapse. This chemical is very toxic to invertebrates. Nicotinic acetylcholine receptors are also present in the nervous systems of mammals. There is concern that neonicotinoids may impact animals other than their insect targets (including humans). Neonicotinoids are known to have sub-lethal effects on bees’ foraging and colony performance.

Taxonomy

To start, let’s be clear about just what insects are. Insects belong to the Kingdom Animalia, Phylum Arthropoda, Class Insecta. There are at least 28 different Orders of insects; the pictures below show the 5 orders that include at least 100,000 species each —greater than the number of all known species of fish, reptiles, mammals, amphibians, and birds combined. WOW — Half of all known living organisms are insects! All insects have a chitinous exoskeleton, a 3-part body, 3 pairs of jointed legs, compound eyes, and one pair of antennae. They live in nearly all environments (including the ocean). Insects do NOT include centipedes, scorpions, spiders, woodlice, mites, and ticks.

Selected orders shown in the slideshow below: 1. Lepidoptera (butterflies and moths, 2. Coleoptera (beetles), 3. Hymenoptera (bees, wasps, hornets, sawflies, ants), 4. Hemiptera (cicadas, aphids, plant hoppers, bed bugs, sheild bugs), 5. Diptera (flies).

Insect Diversity and Biomass

The class Insecta originated on Earth about 480 million years ago, about the same time as terrestrial plants. Until recently, insects have had very low extinction rates; in one group of beetles studied (Polyphaga), there have been no extinctions in its entire evolutionary history, even during the mass extinction event at the end of the Cretaceous period (~66 million years ago).

Roughly 10 quintillion individual insects exist on the planet at any given moment. They make up about 80% of all the known animal kingdom species. About a million insect species have been discovered but it’s generally agreed that, by some estimates, about four million more have yet to be discovered. If you look at the food webs of any species habitat, you’ll find insects playing a role. To understand the importance of each species within a given web, see my previous posts. Although any individual insect species within a given food web may not be considered a keystone species, the larger group of insects are clearly vital to life on land.

Crucial Insect Ecological Contributions

Every insect on the planet is playing a role in the ecological machine. Each individual effort adds up to colossal benefits for life on Earth. Along with these insect *”services” provided, there are also insect “disservices”, for example, pest damage to agriculture, spread of diseases, negative actions as an invasive species, etc. As presented to the general public, these negative affects associated with insects are given far greater coverage than the benefits of insects. Often the insects negative affects in an ecosystem are due to imbalances in nature that were caused by humans.

*Note: I’m not a fan of the terms ecological “services” — if you do much reading about ecology you’re sure to come across the term. Whether it is meant this way or not, it smacks to me of “how does [something found in nature] contribute to improving humans’ life on earth”. We need to stop holding this warped view that all of nature is simply available to “serve” our needs and wants. We need to recognize the importance of the roles that each living thing on earth plays in keeping all of nature in balance so all can be well.

PROVIDERS: Insects are the meal of choice for many larger animals such as birds, bats, amphibians, and fish. These animals are in turn the meal of choice for even larger predators. The decline in insect populations is suspected to be the leading cause of recent declines in bird populations. Insect eating reptiles include geckos, anoles, and skinks. Insect eating mammals include tree shrews and anteaters.

DECOMPOSERS: Waste-eating insects, such as springtails, termites, beetles, etc, recycle nutrients back into the earth for plants to absorb and grow that would otherwise stagnate in dung, dead plants, and carrion. Without insects, dead organic matter would being to pile up. Insects are also used in sewage treatment plants to help decompose and filter matter along with neutralizing toxins.

PEST CONTROLLERS: Insects such as ladybirds, hoverflies, and wasps that eat other crop-threatening insects play the role of pesticides without chemicals, reducing costs to farmers and increasing yields. In addition to killing unwanted insects or weeds, pesticides and herbicides can be toxic to a host of other organisms including birds, fish, beneficial insects, and non-target plants. Surface and groundwater pollution due to pesticides is a worldwide problem. According to the soil scientist Dr. Elaine Ingham, “If we lose both bacteria and fungi, then the soil degrades. Overuse of chemical fertilizers and pesticides have effects on the soil organisms that are similar to human overuse of antibiotics. Indiscriminate use of chemicals might work for a few years, but after awhile, there aren’t enough beneficial soil organisms to hold onto the nutrients”. Pesticides are often considered a quick, easy, and inexpensive solution for controlling weeds and insect pests in urban landscapes. However, pesticide use comes at a significant cost. Weed killers can be especially problematic because they are used in relatively large volumes. The best way to reduce pesticide contamination (and the harm it causes) in our environment is for all of us to do our part to use safer, non-chemical pest control and weed control methods.

POLLINATORS: Nearly 90% of flowering plant species and 75% of crop species depend on pollination by animals — mostly insects. Overall, one out of every three bites of food humans eat relies on animal pollination. Insects also play a critical role in seed dispersal. For example, the seeds of many plants have structures (elaiosomes) that are packed with fats and other nutrition. Ants will carry off the seed, eat only the elaiosome, and leave the rest to sprout.

SOIL ENGINEERS: Termites and ants transform soil through their tunneling which aerates hard ground, helping it retain water and adding nutrients. In some regions of the world, introduction of termites has turned infertile land into cropland within a year.

The Problem

In the late 1980’s, a researcher launched a project to find out how insects were faring in different types of protected areas in Germany. He collected insects from 63 areas over the course of 20 years. In 2013, entomologists returned to two sites that were first sampled in 1989. The mass of trapped insects was just a fraction of what it had been 24 years earlier. The team that sifted through all this data found that between 1989 and 2016, flying insect biomass in these protected areas of Germany declined by 76%. Insect biomass studies conducted in other areas have shown similar results: a protected forest in New Hampshire found the number of beetles had decreased by more than 80% and the beetles diversity decreased by almost 40%. A study of butterflies in the Netherlands found their numbers had declined by almost 85% since the end of the 19th century. A study of mayflies in the upper Midwestern U..S. found their populations dropped by more than half just since 2012. A research station in the tropics of Costa Rica has found a 40% decrease in caterpillar diversity since 1997, and a drop in parasitoid diversity of about 55%. This data is particularly significant given that about 80% of all insect species live in the tropics. The geographic extent and magnitude of insect declines remain largely unknown — there is an urgent need for monitoring efforts, especially across ecological gradients, which will help to identify important causal factors in declines.

Earth is clearly in a biodiversity crisis, not surprisingly when you consider how much of the planet we humans have altered by mowing down forests, plowing up grasslands, planting monocultures, and pouring pollutants into our waters and the air. The rate of insect loss is significantly faster than other animal groups. It is not clear why this would be. Pesticide use would seem a logical culprit, however many of the places where steep declines have been reported are pristine landscapes where pesticide use is minimal. Climate change is suspected to be a major driving factor.

The Culprits and Potential Solutions

In a recent study, questions were posed to expert entomologists on the root causes of potential insect declines worldwide, 413 expert opinions were summarized regarding the relevance of threats to insects as follows (in order of importance):

  1. Agriculture (causing habitat loss and biotic homogenization)
  2. Climate change
  3. Pollution (includes pesticide use, the number one stressor for freshwater invertebrates)
  4. Natural system modifications
  5. Invasive species
  6. Residential and commercial development

The above list refers to all insects worldwide. The main stressors that affect any given insect family may vary and are dependent on their habitat and species. Insects — the most diverse class of animal organisms on the planet — are still severely understudied.

Climate change is believed to be one of the main drivers of insect population decline. Many insect species are very susceptible to extreme weather conditions — they are just not adapted to large fluctuations.. In the words of one researcher, “…the insects run out of food, they run out of cues, everything just falls apart.” Pesticide use and habitat loss are thought to be another main contributing factor in insect decline. The European Union has banned most neonicotinoid pesticides which several studies have linked to insect and bird decline. The German government had adopted an “action program for insect protection”, which includes restoring insect habitat, banning the use of insecticides in certain areas, and phasing out glyphosate (a commonly used herbicide). A group of more than 50 scientists from around the world have proposed a roadmap for insect conservation. It recommends taking aggressive action to reduce greenhouse gas emissions, preserving more natural areas, imposing stricter controls on exotic species, and reducing the application of synthetic pesticides and fertilizers.

The Xerces Society for Invertebrate Conservation based here in Portland, Oregon is one of the few organizations in the world that is specifically devoted to invertebrate conservation. As a science-based organization, they both conduct their own research and rely upon the most up-to-date information to guide their conservation work. Their key program areas are: pollinator conservation, endangered species conservation, and reducing pesticide use and impacts. I highly recommend you take a look at their website to learn more about this great organization: https://xerces.org/. Their introductory video is worth watching:

A Few (kinda interesting) Insect Facts

  • Globe mallow bees don’t make hives; the females sleep in ground nests and males curl up inside the globe mallow flowers. If all the blooms are booked, a male bee will nestled alongside another bee and convert the single room to a double.
  • While many invertebrates fill the seas, and a small fraction of insect species live at the edges the ocean or in the intertidal zones, there is only one insect that lives on the surface of the open ocean: the sea strider (Halobates). This carnivorous insect sprints on the water surface looking for prey that has fallen onto the water, such as zoo- plankton, fish eggs, larvae and dead jellyfish. In turn, it provides a source of food for sea birds and surface feeding fish.
  • Researchers have observed chimpanzees catching insects and putting them into wounds on themselves or other chimps. They catch the insect, squeeze it between their lips to immobilize it, then place it on the wound moving it around with their fingertips, and finally removing it with their fingers or mouths. Sometimes the insect would be put in and out of the wound several times. At the least, it’s interesting behavior. Yet it seems quite possible that they are in some way treating the would….chimp TEK (Traditional Ecological Knowledge)!
  • Some insects have evolved into remarkably specialized roles within their habitats. The moth caterpillar (Ceratophaga vicinella) scavenges only on the tough keratin shells of dead gopher tortoises. You can see how the extinction of these specialized insects can unravel the balance in an ecosystem.
  • Dragonflies move each of their four wings independently, flapping each up and down and rotating them forward and back. They can move straight up and down, fly backward, hover and stop, and make hairpin turns at full speed or in slow motion. They can fly at speeds up to 30 mph. AND they can eat up to 100 mosquitos per day.
  • Many insects live off other insects — most parasitic wasps lay their eggs in the bodies of caterpillars, using their hosts as a source of nutrients. Other insects, known as hyperparasitoids, lay their eggs in or on the bodies of parasitoids. There are even insects that parasitize hyperparasitoids!
  • Fireflies have dedicated light organs under their abdomens that they use for finding mates. They do this by combining oxygen and a substance called luciferin they hold in special cells. This light produces no heat. Fireflies flash in patterns that are unique to different species. Some species synchronize their lighting — coordinating their flashes into bursts that ripple through the entire group of insects.

MAKING THE CONNECTION

I started writing this post with the vague notion that I now observe far fewer insects in the environment than I remember from decades ago, along with some sneaking suspicions about what some of the causes of this decline could be. During my research phase, I was particularly alarmed to discover just how widespread and drastic global insect die-off has occurred, and in such an incredibly short period of time. I hope, given the content I’ve included here, that you have also been able to make these connections: incredible diversity and overall biomass of the class Insecta, what they contribute to the overall balance of nature along with the importance of these contributions, and the causes for their decline (both proven and suspected by experts in the field).

It’s time for ALL people on this planet to change their relationship with nature, which requires some radical changes in how we live our lives. The damage we are currently causing to the planet is quite simply not sustainable. I suspect that on some level everyone knows this and many are afraid to acknowledge it because they do not want to give up their current way of life. There is often a push to “live in the moment”, which can be comforting and soothing, but we also must be disciplined in preparing for our future. We need to develop a new relationship, based on respect and gratitude, with the our incredible, miraculous home — earth. There are so many organizations and individuals around the world that are already engaged in this work. Some of the business sector is even recognizing the need for change and moving in the right direction. I encourage everyone to continue learning and take whatever actions you feel called to take to help support these efforts. It is only by the participation of everyone who calls the earth “home” that we can continue to live in comfort and harmony with nature.

WORKS CITED

Beaver: the Ultimate Keystone Species

A Bit of History:

During the nineteenth century, man’s extermination of any living creature that had fur or feathers was so extreme that some have dubbed the period the “Age of Extermination”. It is estimated that between 60-400 million beaver populated North America prior to the 1500’s. By the 1900’s, there were about 100,000 beavers left. We currently have about 15 million beaver — it is not an endangered species, but it’s numbers are certainly reduced from it’s historical representation. Let’s explore what makes beaver such an important keystone species with respect to wetland habitats.

DEFINITIONS:

  • Wetland: An area of land saturated with water. There are five types of wetlands: ocean, estuary, river, lake, and marsh. In this post, we are referring to river wetlands.
  • Hyporheic zone: Describes the area in a stream bed where the water moves in and out carrying dissolved gas and solutes, contaminants, particles, and microorganisms. Depending on the geology and topography, the hyporheic zone may be only a few centimeters deep or extend up to tens of meters deep. Both water mixing and storage happen here.
  • Hyporheic exchange: Refers to the speed at which water enters or leaves the hyporheic zone. The rate of exchange can be quite variable depending on a number of structural and geomorphic factors.
  • Incised stream / Degraded channel: A stream channel in which the bed has dropped and as a result, the stream is disconnected from its floodplain.
  • Floodplain: The flat area adjoining a river channel constructed by the river in its present climate and overflows during moderate flow events.
  • Algal blooms: A rapid increase in the population of algae in a freshwater or marine system. Algal blooms refer to microscopic unicellular algae, not macroscopic algae. The bloom is a result of excess nutrient (like nitrogen or phosphorous from fertilizers) entering an aquatic system and causing excess growth.

Wetland Habitats — Why are they Important?

We now recognize wetlands to be critical habitat for a healthy ecosystem and focal points of biodiversity, however they were historically viewed as places of darkness, disease and death. In short, they were considered wastelands that needed to be converted to usable land. It would be impossible now to restore our landscape such that it could support the historical number of beaver seen in the early 1800’s as the landscape is too altered by humans — homes, roads, pastures, and orchards with many streams that have degraded to the point that beaver are unable to restore them to wetland areas. Ben Goldfarb, in his book Eager quotes Kent Woodruff of Washington’s Methow Beaver Project as saying “We’re not smart enough to know what a fully functional ecosystem looks like, but beaver are.”

In the western U.S., wetland habitats cover about 2% of land area yet support about 80% of species biodiversity. These habitats provide numerous critical functions, such as: water filtration, flood and erosion control, food and shelter for fish and wildlife, absorbing and slowing floodwaters, absorbing excess nutrients (e.g. nitrogen from fertilizers), heavy metals, and sediments before they reach rivers, lakes, and other water bodies. They also serve to provide wildfire breaks in the landscape.

The Amazing Beaver

The North American Beaver (Castor canadensis) are best known for their unrelenting desire to build dams, often to the distress of land owners that don’t particularly want their land flooded. Beaver are rodents that weigh about 60 pounds and can live up to 24 years. Interesting physical characteristics include:

  • Extremely dense fur — this feature is what the early pioneers sought to make hats and use for trading.
  • Duck-like hind feet that make them agile swimmers.
  • Ability stay underwater for up to 15 minutes.
  • A second set of eyelids that function as goggles underwater.
  • A second set of lips that can close behind their front teeth so they can chew and drag branches underwater without drowning.
  • A multi-functional tail serving as a rudder, fat storage and thermoregulatory device, and alarm system by slapping it against the water to warn other beavers about the presence of predators.
  • Amazing incisors that grow continuously and self-sharpen as they gnaw down trees.

Beaver are totally herbaceous, eating the cambium (inner sugary layer of trees) mostly from willow, aspen, cottonwood, as well as other green vegetation. They create two types of structures with trees; the lodge which serves as living space with underwater tunnels and an elevated nesting chamber, and dams. Generally 2 – 8 beavers inhabit one lodge — the adult mating pair and three years of offspring. Beaver build both of these structures in order to extend their habitat. They are quite vulnerable to predators (bear, cougars, coyotes, and wolves) on land but much safer underwater, so by extending the surface area of water they are providing their own protection. Dams hold water in low-gradient areas creating ponds which submerge their lodge entrances and give them a place to stash their food caches. The ponds created by the dams also irrigate water-loving trees allowing beavers to operate as rotational farmers — they’ll cut down vegetation in one area while cultivating their next crop in another.

A beaver lodge I came upon while enjoying a picnic in southern France

Beaver dams range in size from quite small (1 x 3 feet) to quite large (15 feet high by a half-mile long). There are three basic requirements needed in order for beaver to set up shop in a given riparian area; water (wadable creek-type), a low valley landscape that allows a gentle stream flow to avoid blowing out their dams, and deciduous vegetation in sufficient quantity for food and construction material. If a stream is allowed or forced to become incised, it becomes challenging for beavers to establish themselves since incised streams tend to blow out the dam(s) during times of heavy stream flow. The pond created by the dam provide a number of benefits to the beaver: underwater escape from predators, increased foraging areas, allowing logs and branches to float in the water, and ensuring the entrances to their lodges remain underwater. Sometimes several dams are built by the same colony. If beaver inhabit an area that already has existing and adequate pond coverage, they will not build dams.

The Benefits of Beaver Dams

American farmers collectively add about twenty million tons per year of fertilizers to agricultural fields. Rain sweeps much of the excess nitrogen and phosphorous from these fertilizers into rivers and eventually into lakes and seas. Suburban lawns, septic tanks, and even cars contribute to this nitrogen dump into watersheds. This nutrient stew fertilizes algal blooms that decompose when they die off, devouring dissolved oxygen in the water and giving rise to “dead zones” — lifeless expanses of anoxic water that drive away all fish and kill stationary bottom dwellers. Global oceans are afflicted by nearly a hundred thousand square miles of dead zones. One solution to this crisis is healthy wetlands which, like kidneys, filter out suspended nutrients and other pollutants long before they reach the sea. In addition to beaver ponds capturing and storing excess nutrient run-off, one study has shown that bacteria living in the sediment of beaver ponds broke down added nitrate, effectively purging the pollutant from the water by converting it to nitrogen gas.

Beaver are amazing architects of wetland ecosystems. Here’s a short list of other species that benefit from sharing beaver habitat:

  • Primary producers such as algae and diatoms increase as more sunlight becomes available (not to be confused with an algal bloom), this leads to more secondary producers such as micro-and macroinvertebrates. The secondary producers form the base of the food web that young salmon and steelhead rely on.
  • Aquatic insects live in the spaces created by dams and lodges.
  • Waterfowl and other bird species increase due to the abundance of aquatic insects for food as well as increased vegetation for protection from predators.
  • Amphibians, turtles, and lizards are more abundant near beaver ponds.
  • Wetland plant species increase in areas where beaver are present. Initial loss of trees and shrubs due to flooding opens up the landscape to allow more sunlight into the expanded riparian area.
  • Fish communities are more diverse. Fish expend less energy foraging in the slow productive waters of beaver ponds.
  • Mink and raccoon hunt crawdads and snakes in beaver complexes.
  • Nutrients from beaver feces breed zooplankton.
  • Sawflies lay eggs on beaver-browsed cottonwood shoots.
  • Moose follow beaver ponds to feed on the wetland plants.
  • And on and on….

The potential ecological benefits of restoring beaver to appropriate landscapes include: higher water tables; reconnected and expanded floodplains; more hyporheic exchange; higher summer base flows; expanded wetlands; improved water quality; greater habitat complexity; more diversity and richness in the populations of plants, birds, fish, amphibians, reptiles, and mammals; and overall increased complexity of the riverine ecosystems.

In light of all the ecological benefits attributed to beaver, it becomes clear why many scientists consider beavers to be the “ultimate keystone species”.

Making the Connection

Conservation biologists point out that people often fall victim to shifting baselines syndrome. This is a type of long-term amnesia that causes successive generations to accept its own degraded ecology as normal. Salmon fisherman that boast of catching ten-pound chinook forget that their fathers once hauled out fifty-pound chinook. Current biologists who marvel at mayfly hatches never experienced the insects emerging in clouds so thick their bodies piled up in three-foot windrows. Every year our standards slip a little further; every year we lose more and remember less. Currently, there are more than 142,500 species on The IUCN Red List, with more than 40,000 species threatened with extinction, including 41% of amphibians, 37% of sharks and rays, 34% of conifers, 33% of reef building corals, 26% of mammals and 13% of birds. This data is stunning and should be causing everyone to act as if their hair were on fire. Those of us that have been around for many decades can usually relate to the concept of shifting baselines syndrome; I recall from my younger days how the insect splats on a car windshield used to require regular windshield cleaning whereas now you hardly notice any splats.

The intersection of human and wildlife habitats tends to be fraught with conflict. When beavers choose urban settings to set up their household, this conflict plays out with flooded roads or fields and unwanted vegetative chewing. The tendency is often for humans to either physically remove (relocate) or kill the offending wildlife. When there is an understanding of the benefits that the beavers can provide even in an urban setting, a wiser alternative is to consider each situation and look at the full range of alternatives available for mitigating the problems while allowing the beaver to stay. These alternatives include placing fencing around culverts, notching inactive dams, and placing deterrents on active dams that may inhibit rebuilding, placing protective wire meshing on trees. It is also important to provide education where needed to engage farmers, city managers, etc. in understanding the benefits that beaver will provide to a local ecosystem. This has been done successfully in many areas around the country. Several states now have beaver management protocols in place.

Our world will always be improved when we work with nature instead of against it. For far too long man has viewed the natural world as a resource to be exploited without regard for the harm caused in the process. More and more people are coming to realize, now that our one and only planet is in crisis, that we need to better understand, protect, and preserve everything that exists in the natural world because it is all interconnected and necessary for the health of the whole. I hope this blog is helping you to understand that when we sever the links between vital species in an ecosystem there are always negative repercussions if not total collapse. There are many incredible individuals and organizations working to provide sustainable solutions to problems that crop up in the interface between human activities and various species that are trying to go about their lives.

For more information about beaver, I recommend this site: https://www.beaversww.org/. I’m including a video from this site.

WORKS CITED:

The Mighty Diatom and the Air we Breathe

Raise your hand if you know what a diatom is. Don’t feel bad if you didn’t raise your hand; you are in the majority of people around you. Maybe you recall your 7th grade biology teacher mentioning them, but you never quite understood what they were. I say it’s high time we understood them a bit better given that these mighty diatoms are responsible for producing about 50% of the oxygen we breathe through that amazing process — photosynthesis. Yes, something that is microscopic and virtually unknown by most people is responsible for a critical element, O2, that is vital to sustaining life on earth.

DEFINITIONS:

  • Micron: Also known as a micrometer — a unit of length equal to one millionth of a meter.
  • Organelles: Specialized structures that perform various jobs inside cells. Literally “little organs”; just as familiar organs (heart, lungs, kidneys, etc.) serve specific functions to keep an organism alive, organelles serve specific functions to keep a cell alive.
  • ATP: Adenosine Triphosphate — an organic compound that provides energy to drive many processes in living cells. It is found in all known forms of life. The human body recycles its own body weight equivalent in ATP every day.
  • NADP+: Nicotinamide adenine dinucleotide phosphate — a cofactor used in anabolic reactions (like the Calvin Cycle). NADPH is the reduced form of NADP+.
  • Stroma: Tissue that serves a structural or connective role in a cell.
  • Plankton: Includes a diverse collection of organisms found in water or air that cannot propel themselves against a current. Some examples include bacteria, algae, protozoa, plant spores, pollen. Most are microscopic however some are quite large, including jellyfish. They are a crucial food source for many small and large aquatic organisms.

What are Diatoms?

Diatoms are single-celled algae found in the oceans, waterways, and soils of the world. They are the only organism on the planet with cell walls composed of transparent, opaline silica. They are quite beautiful and unique when viewed under the microscope displaying an amazing kaleidoscope of shapes. I’ve added a few pictures below. You can also check out some of the references below for good pictures. Their size ranges from 2 – 500 microns with the largest being about the width of a human hair. They constitute about half the organic matter found in the ocean. There are an estimated 20,000 – 2,000,000 different species of diatoms with more being discovered every year. Various species have developed structural adaptations to be able to move about or attach themselves to rocks or other organisms. This may allow them to stay afloat or resist wave action as needed depending on their environment. Diatom species are particular about the quality of water they live in.

What is Photosynthesis?

Like plants, diatoms and other algae use sunlight to transform water and carbon dioxide into oxygen and simple carbohydrates during the process known as photosynthesis — didn’t your 7th grade teacher also mention something about photosynthesis during biology class? Considering that photosynthesis is essential for the existence of all life on earth, it seems important to have a basic understanding of that process. Here’s my very simplified explanation of how photosynthesis works.

The photosynthesis process takes place in cell organelles called chloroplasts. Chloroplasts contain a green-colored pigment call chlorophyll — chlorophyll is responsible for the green coloration in plant leaves. Phototsynthesis occurs in two stages: a light dependent reaction and a light independent reaction (the Calvin Cycle). The light dependent reaction occurs in the thylakoid cells where energy from sunlight is converted to ATP and NADPH which is then used to power the Calvin Cycle. During the light reaction, the hydrogen from water is used and oxygen is produced. The light independent reaction, or Calvin Cycle, is also referred to as the carbon-fixing reaction. This reaction occurs in the stroma of the chloroplast. Water and carbon dioxide, along with the ATP and NADPH are converted to sugar (glucose) molecules that feed the plant.

Diatoms in the Great Lakes

Diatoms comprise the bottom rung of an aquatic food web. Zooplankton (small protozoans that feed on other plankton) feed on algae, smaller fish feed on zooplankton, bigger fish feed on smaller fish, and on up the food chain. Diatoms are busy photosynthesizing year round, even in lakes covered by both ice and snow. Diatoms need just the right balance of depth and sunlight to do their thing. If they sink too deep they don’t get enough sunlight, and if they are higher in the water column they can get burned. Snow may be protective against too much sunlight. Without diatoms to support zooplankton during the winter months, the lakes productivity for the rest of the year suffers.

Researchers have found that, over the past 115 years, individual diatoms are getting smaller and this decrease in size seems related to climate change. As the lakes become warmer, the bigger diatoms sink and are unable to harvest adequate sunlight to photosynthesize. The trend is toward smaller diatoms and fewer of them. Additionally, invasive species of mussels that have been introduced into the Great Lakes have caused the numbers of diatoms to plummet; mussels can filter the amount of water in Lake Michigan (removing plankton, including diatoms) in about a week or less. In Lake Erie, diatom numbers have plunged 90% in the last 35 years. A loss of this magnitude in a keystone species should be alarming to everyone, but again, think about how many people even know what a diatom is.

How do Diatoms Reproduce?

I’m suspecting you remember more about human reproduction from your 7th grade Biology teacher than diatom reproduction, but hang in here…this is fascinating!

Diatoms reproduce by both an asexual and a sexual process. The asexual process is primary and occurs by binary fission to produce two new diatoms with identical genes. You can see from the diagram below that the frustule splits to form two daughter cells; one with the larger half of the frustule (the epitheca) and one with the smaller half (the hypotheca). The diatom that receives the hypotheca remains smaller than the parent. With continued asexual reproduction, the average cell size of the diatom population decreases.

In order to restore the diatom population to it’s original cell size, sexual reproduction occurs through meiosis. A special structure, called an auxospore, is formed. This is a unique type of cell that possesses silica bands rather than a rigid silica cell wall. This unique cell allows the cell to expand to it’s maximum size. Once an auxospore divides by cell division, it produces a normal diatom cell which then continues to get smaller with each asexual cell division.

Diatoms in the Fossil Record

The silica cell walls of diatoms are inorganic, so they do not decompose. These structures are found in the fossil record back as far as the early Jurassic (~185 million years ago). It has been suggested that the evolutionary ability of these organisms to produce a resting stage (the Auxospore) along with the ability to photosynthesize had an adaptive advantage over other organisms during intense climatic, tectonic, and geochemical changes that led to a mass extinction period close to the Permian-Triassic boundary (~251 million years ago). After the mass extinction event, many niches (habitats) in the aquatic realms opened up and diatoms appear to have diverged at this time and evolved to develop silicic cell walls. Thus, they are found in greater abundance in the fossil record since this time. The fossil record shows diatom diversity to be very sensitive to global temperature. Warmer oceans, particularly warmer polar regions, have in the past been shown to have substantially lower diatom diversity. Thus, future warmer oceans could, in theory, result in a significant loss of diatom diversity although it is unclear how quickly this change would happen.

MAKING THE CONNECTION:

I hope I have led you to a greater understanding and appreciation of what diatoms are and the important role they play in sustaining life on earth. By studying the fossil record, we know diatoms have been with us for millions of years and have evolved over time as climactic and geochemistry conditions changed. We also know that in order for organisms to adapt to changing conditions (evolve), changes need to occur relatively slowly. We can observe today how local conditions in lakes and oceans are affecting diatom populations. We can also acknowledge that there is a lot more to learn about how diatoms adapt, and how quickly, to changing conditions. One thing seems clear — we should be showing more gratitude and respect for these amazing organisms. So the next time you take a big gulp of air (like now) remember to give thanks to the mighty diatoms who work tirelessly to keep us supplied with oxygen!

REFERENCES:

The Gray Wolf: An Apex Predator Story

The gray wolf’s (Canis Lupus) story is a fascinating account of species near-extinction and comeback in the American west. Here, we will look at some specifics about the gray wolf, what an apex predator is, the gray wolf’s re-introduction into the northern Rocky Mountains and why the wolf and apex predators in general are vital players in a healthy ecosystem. We’ll also introduce the idea of using both Scientific Ecological Knowledge (SEK) and Traditional Ecological Knowledge (TEK) as a means of restoring an ecosystem.

DEFINITIONS

  • Apex Predator: The top predator in a food web, without any natural predators.
  • Mesopredator: A mid-ranking predator in a food web.
  • SEK (Scientific Ecological Knowledge): Scientific knowledge generated through a strict and universally accepted set of rules formed by academic disciplines (ecology, biology, forestry, etc). Addresses the return of an ecosystem to a close approximation of its condition prior to disturbance. In restoration, ecological damage is repaired; both the structure and the function of the ecosystem are recreated. Time frame is in decades.
  • TEK (Traditional Ecological Knowledge): Describes indigenous or other traditional knowledge of local resources handed down through generations generally through traditional songs, stories, and beliefs. It includes the restoration of relationship to land, based on respect and reciprocity for the gifts we receive from the land. A partnership with dynamic natural processes. Time frame is in generations.
  • Reference Ecosystem: A community of organisms that serve as a model or benchmark for restoration following a disturbance by human activities such as agriculture, logging, development, fire suppression, or non-native species invasion.

Wolves are the wild ancestor of all domesticated dogs. Their body size varies from three to five feet long with a tail of one to two feet long. Females weigh from 60 to 100 pounds and males range from 70 to 145 pounds. Their average lifespan is 8 to 13 years. They are carnivores that prefer large hoofed mammals but will also eat smaller mammals, generally eating every 5 – 7 days. Wolves live in packs of 2 – 15 members but can increase up to 30 members before some individuals break off to find new territory. There are both male and female hierarchies in the pack; the alpha male is dominant over the entire pack and only the alpha male and alpha female breed. Breeding occurs from late January through March, gestation is about 63 days, and there are typically 4 to 6 pups in a liter. Wolves communicate through body language, much in the same way our domesticated dogs do. Howling is used for long-distance communication to pull a pack together.

The wolf was once widespread across most of North American but it was hunted to near extinction in the early 1900’s. Today the North American Gray Wolf ranges across the Northern Rockies, the Pacific Northwest, the Western Great Lakes Region, from the US/Canada border into the Arctic (including Alaska and Greenland), in a small region along the
Arizona/New Mexico border, and a few struggling to survive in Mexico. In the 1800’s, Yellowstone National Park was once home to several large predators including grizzly bears, black bears, wolves, and mountain lions along with a robust population of bison, elk, mule deer, pronghorn, and bighorn sheep. The last Yellowstone wolf pack was killed by humans in 1926. With the wolves gone, the bear and lion populations greatly diminished and the elk populations skyrocketed. Elk populations continued a boom and bust cycle due to targeted killing as well as fluctuation due to climate variability. Fast forward to 1995 when, in an effort by the federal government to remove the gray wolf from the endangered species list, 41 gray wolves were reintroduced into Yellowstone National Park and additional wolves were reintroduced into Idaho. Some people were concerned that this reintroduction would wipe out the elk populations. However 25 years of study has shown that the wolves prey on the weaker, undernourished, bull elk and older cow elk which has helped to create a much more resilient and balanced elk population. The wolves also prey on elk calves, however this has not led to an overall reduction in survival of elk calves. In Idaho, state pushback to the wolf reintroduction program led to turning over the management of the project to the Nez Perce Indian tribe who viewed the wolf recovery efforts as linked to the recovery of their tribe as well. The tribe was eager to restore the biodiversity and ecological balance of the northern Rocky Mountain ecosystem. Like many Native Americans, the Nez Perce have a special affinity with the wolf, and share a similar history of persecution and being forced onto ever-smaller habitats. Restoring the gray wolf to its historic range allowed the tribe to reestablish its cultural ties to the wolf. Importantly, the gray wolf recovery effort marked the first time a native tribe was able to take the lead role in reintroduction of an endangered species.

Wolves fill a unique role in an ecosystem both as an apex predator and a keystone species. Recall from the previous post (The Oregon Alligator Lizard and his Food Web) that a keystone species plays a critical role in a food web. If a keystone species is removed from a food web, the ecosystem would change dramatically. An apex predator is at the top of the food web of a given ecosystem (“top dog” in this case), and also has a profound effect on the functioning of the ecosystem. Wolves help restore stability to their ecosystem by providing scavenging opportunities for other animals and improving riparian areas by hunting herbivores. In Yellowstone, for example, the reintroduction of wolves forced elk to stay on the move, freeing sensitive riparian areas from overgrazing and allowing vegetation to recover along streams. More willows and aspen trees provide food and habitat for beavers. Beaver ponds benefit aquatic habitats in several ways including allowing trees to provide shade to cool the water and improve habitat for fish. Wolves also help to control the coyote (a mesopredator) populations, which in turn allows the rodent populations to increase and provide food for struggling birds of prey. The remains of a carcass left behind by wolves help feed grizzly bears, bald eagles, wolverines, and other scavengers.

Wolf chasing prey

Apex predators influence ecosystems in several important ways including limiting the number of prey in a habitat (i.e. elk in Yellowstone) and thereby controlling smaller mesopredators. Without apex predators, a habitat experiences an outbreak of mesopredators which leads to diminished biodiversity. Studies have shown that apex predator populations are self-regulated. Whereas small carnivores share fast reproduction rates and have higher densities, large carnivores (like wolves) have a slow reproduction rate, extended parental care, sparsely populated territories, reproductive suppression, shared parental care, and cooperative hunting. This self-regulation may ensure that the largest and fiercest do not overexploit their resources.

MAKING THE CONNECTION

In my last post I introduced the concept of a food web and how the interconnectedness of species within a given food web is vital to a healthy ecosystem. Here I’ve tried to hone in on the importance of apex predators in food webs. This is an important concept to understand since many of our apex predators are viewed by humans as threatening and in need of “control” or extermination. Wolf restoration programs are generally viewed as positive by people that have the least experience with them and negative by people who live in areas where wolves reside and sometimes prey on livestock. In North America, livestock does not make up a major portion of wolf prey. Furthermore, wolves do not automatically hunt livestock, although they may learn to kill them at some point. Confirmed wolf depredations make up a comparatively small portion of all livestock losses. If livestock owners engage with wildlife management agencies to address concerns about predation, the tensions that exist between these groups can be reduced. Yellowstone National Park is actually a rare place where wolves are completely protected. The reintroduction and monitoring of the wolf packs of Yellowstone has provided a unique opportunity for people to understand the true nature of these animals. We are able to see that they are subtly restructuring the ecosystem.

Robin Wall Kimmerer guides us to think about ecological restoration of our land through two lenses: SEK and TEK or indigenous ways of knowing + western scientific knowledge. She explains that it is not only the land that is broken, but our relationship to the land that is in need of repair. TEK is an important overlooked resource in ecological restoration. Reference ecosystems can be identified using SEK however with TEK, information on a reference ecosystem relies upon oral history, ethnographies (the customs and cultures of a group of people), harvest practices, management practices, and material culture. Incorporation of TEK allows movement from simply ecological restoration to biocultural restoration. Kimmerer explains that “biocultural restoration is an approach to healing damaged lands and to healing relationship between people and place with the aim of generating a mutually sustaining, life-renewing landscape which supports the livelihoods of both human and more than human beings who are dependent on that landscape.” This practice draws on multiple ways of knowing. It leads to reciprocal restoration, where restoration of land and ecosystems contribute to cultural revitalization and, in turn, this renewal of culture promotes restoration of ecological integrity. I encourage you to listen to Kimmerer speak more fully on this topic (see reference #9).

ADDENDUM

I mentioned above that when the gray wolf population was absent in Yellowstone National Park the bear and mountain lion populations decreased. I’d like to provide some further research and discussion on why this would happen.

Let’s first look at the wolf – bear interactions. Grizzly bears, black bears, and gray wolves have historically shared habitat throughout their range in North America. These interactions revolve around food sources and are characterized as “mutual avoidance”. Wolves may occasionally kill weak or young bear and bear have been noted to occasionally kill wolves, but these interactions are rare; most interactions between the two species are stand-offs as they defend their young or food source. Wolves prey on ungulates year-round whereas bear feed on ungulates primarily as winter-killed carcasses (after emerging from their dens) or ungulate calves in the spring. Bear mainly feed on grasses, sedges, forbs (flowering plant), berries, nuts, and roots. In YNP, most early-winter wolf-killed carcasses are consumed by coyotes before bears emerge from their dens. It has been suggested that bears benefit from wolf presence in the park because wolves prey on ungulates year-round and since bears readily displace wolves from their kill, this allows a more reliable food source for the bear for a larger portion of the year.

Now let’s look further at wolf – mountain lion interactions. A recent study showed that where these two species overlap in an ecosystem, wolves cause a decrease in mountain lion numbers by starving out adults and killing their kittens. When wolves are absent in a habitat, elk herds spread out and reside in relative comfort in mountains. However when wolves are present, elk herds congregate in larger groups in open grasslands to protect themselves from a wolf pack attack. Since mountain lions stalk and ambush their prey under cover of brush, they are less effective in hunting in the grasslands and starvation becomes an issue for the cats. Recent studies show the effect of wolf populations on mountain lions to be profound and much more impactful that human hunting of mountain lions.

It seems the earlier statement made about both bear and mountain lion populations decreasing when wolves are absent from an ecosystem may be outdated. More recent research that has been conducted since the wolf reintroduction into YNP seems to indicate that there is at least a benefit for bear to share habitat with wolves and a sort of equal standing between the two species allowing them to co-exist. However it seems clear that mountain lion populations definitely suffer a decline when sharing habitat with wolves.

I hope this discussion further illustrates the complex interactions between various species in an ecosystem and the delicate balance needed to maintain a healthy, functioning food web.

REFERENCES:

  1. Kesselheim, A. The Howling Wilderness. January 2021. The Sun. Chapel Hill, NC.
  2. https://www.nationalgeographic.com/animals/2020/07/yellowstone-wolves-reintroduction-helped-stabilize-ecosystem/
  3. https://www.nationalgeographic.org/media/gray-wolf-educator-guide/?utm_source=BibblioRCM_Row
  4. https://academic.oup.com/bioscience/article/53/4/330/250155
  5. https://onlinelibrary.wiley.com/doi/abs/10.1111/oik.01977
  6. https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/Gray-Wolf
  7. https://digitalrepository.unm.edu/cgi/viewcontent.cgi?referer=https://search.yahoo.com/&httpsredir=1&article=1650&context=nrj
  8. https://en.wikipedia.org/wiki/Apex_predator
  9. https://www.youtube.com/watch?v=qioZC81b7WM
  10. https://dfw.state.or.us/Wolves/docs/2019_Oregon_Wolf_Plan.pdf
  11. https://www.nps.gov/yell/learn/nature/bearwolves.htm
  12. https://www.smithsonianmag.com/science-nature/how-wolves-western-united-states-are-driving-down-mountain-lion-populations-180976775/

The Oregon Alligator Lizard and his Food Web

Several years ago my son came home from a hike and shared with me a picture of a lizard he found. After a bit of quick detective work we identified it as an Oregon Alligator Lizard (Elgaria multicarinata scincicauda). Coincidentally, I was engaged in doing coursework to become an Oregon Master Naturalist. We were currently studying the Fundamentals of Ecology and were given an assignment to create a food web for any given species. What you see below is the food web I created for the Oregon Alligator Lizard.

DEFINITIONS:

  • Food Chain: A linear system showing a succession of organisms whereby each species is eaten in turn by another species.
  • Food Web: A graphic model showing many food chains linked together to depict the feeding relationship of organisms in an ecosystem.
  • Apex Predators: The predator at the top of a food chain that is not preyed upon by any other animal.
  • Keystone Species: A species that has a large impact on its environment relative to its abundance. It plays a critical role in a food web by determining the types and numbers of various other species in the ecosystem. Without the keystone species, an ecosystem would be drastically different or collapse. Keystone species are sometimes, but not always, apex predators.
  • Trophic Levels: Describes the hierarchy in a food web which groups organisms based on the same number of steps removed from the primary producers.

The Oregon Alligator Lizard is a subspecies of the Southern Alligator Lizard (Elgaria multicarinara). It is a reptile native to the Pacific Coast of North America from Washington state to Baja California. This species has adapted to many diverse habitats however it is partial to foothill oak woodlands. Although it is listed by the IUCN Red List as “least concern” it is still a declining species due to habitat loss. It is carnivorous and feeds on a wide variety of prey — basically anything it can get it’s mouth on. They are also known to be cannibalistic, eating their own young, or adult males and females eating each other. This has been demonstrated in my food web diagram by the arrow going from and pointing to the lizard.

Cannibalism is an interesting, if somewhat disturbing, ecological interaction between species. It has been recorded in more than 1,500 species. Not unexpectedly, cannibalism increases in environments where other usual food sources are not meeting the needs of individuals. However, there are other reasons why individuals of a species may turn to cannibalism: as a way to regulate population numbers and increase access to necessary resources (shelter, territory, food), and increased mating opportunities. A feedback loop occurs when cannibalism decreases a species population density to the point where it becomes more beneficial to forage in the environment for other food sources than for cannibalism to occur.

A food chain refers to a succession of organisms in an ecological community where each organism is dependent on the next as a source of food. The basic food chain for the Alligator lizard would look like this:

Hawk —> Snake —> rodent —> Alligator lizard —> cricket —> vegetation

A food web is made up of a complex of interconnected food chains. Organisms in a food web are grouped into trophic levels. The basic trophic level categories are Producers, Consumers, and Decomposers.

Producers, or autotrophs, make up the first trophic level — they make their own food and do not depend on other organisms for nutrition. In my food web example, the plants and algae are the autotrophs.

Consumers are categorized as follows:

  • Primary consumers are herbivores (plant eaters). They are considered to be at the second trophic level. In my food web the insects, tadpoles, and snails/slugs are part of the second trophic level.
  • Secondary consumers eat herbivores. They are at the third trophic level. In my food web, the spiders, alligator and other lizards are part of the third trophic level.
  • Tertiary consumers eat secondary consumers. They are at the fourth trophic level. In my food web, the snakes, wolves, hawks and owls are in the fourth trophic level.
  • There may be additional trophic levels of consumers before a food chain reaches it’s top predator — the apex predator. Apex predators have no natural enemies except humans. In my food web, the eagle is the apex predator.

Decomposers complete the food web by eating non-living plant and animal remains. They turn organic waste into inorganic material thereby returning nutrients to the soil or ocean for use by autotrophs to begin a new food chain. In my food web, the fungi, algae, and ground beetles are all decomposers. Beetles are actually considered both consumers and decomposers.

It makes sense to think of a food web as it relates to an ecosystem. Some examples of ecosystems include a forest, desert, marine, tundra, grassland, coral reef. My food web example would be part of a freshwater ecosystem. Food webs are defined by their collective biomass, or the available energy in the living organisms. The web’s biomass decreases with each trophic level; there are more autotrophs than herbivores, more herbivores than carnivores, and relatively few apex predators. This allows the ecosystem to remain in balance and recycle biomass.

Every link in a food web is connected to at least two others. When one link in the food web is broken, particularly if there is a decrease or extinction of a keystone species, the entire food web is weakened or may collapse all together. Habitat loss is often a culprit in the weakening of food webs. Consider the decline in the salmon populations over that past few decades. One of the main reasons for this decrease is the loss and degradation of habitat from dam construction, stream pollution, lack of shade trees and woody debris in streams, over-irrigation, etc. With less salmon available, bears are forced to turn to other available food sources like ants. Since ants are decomposers, fewer ants means fewer nutrients returning to the soil which can support fewer autotrophs.

MAKING THE CONNECTION:

Once you have an understanding of how interconnected various species are simply on the level of who-eats-whom, and the necessary components that keep this cycle in balance, it becomes easier to understand why biodiversity is important to all life on earth. All life is dependent on the availability of water and nutrients to sustain a given organism. Humans, in general, have lost their intimate connection to the land and the importance of caring for the other beings we share the planet with. The ease of a quick drive to the grocery store has disconnected us from the understanding of how the foods found within were produced — what beings gave their lives so that we can eat and continue our own existence? Every meal should be taken in gratitude and commitment to ensure the harvest is sustainable. We depend on healthy ecosystems for our long-term survival.

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REFERENCES:

https://www.nationalgeographic.org/encyclopedia/food-web/

https://ielc.libguides.com/sdzg/factsheets/southernalligatorlizard/summary

https://en.wikipedia.org/wiki/Cannibalism

https://www.fws.gov/salmonofthewest/poorhabitat.htm

https://extension.oregonstate.edu/mn

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Trees and their Fungal Friends

The relationship between plants and fungi is a very old story. Plants were able to move from water to land about 400 million years ago because of their relationship with fungi which served as their root systems until they evolved to develop their own roots. Millions of different fungal species inhabit the earth and a majority of these dwell in the soil.  Soil fungi are grouped into 3 categories: decomposers, mutualists, and pathogens. In this article, we are only looking at the mutualists; specifically, the fungal species that have adapted to live communally with trees where both tree and fungi benefit from establishing a relationship.

DEFINITIONS:

  • Hyphae — individual fungal threads, usually between 1-10 thousandths of a millimeter in diameter. A single hyphae can grow up many meters long.
  • Rhizomorphs –—an aggregation of hyphae intertwining like strands of a rope making a “root-like” structure.
  • Mycelium — The thallus, or vegetative part, of a fungus made up of a mass of branched hyphae. Mycelial networks can extend over tens or hundreds of meters.
  • Mycorrhiza — a mutual, symbiotic relationship between a fungus and a plant, unlike either fungi or roots alone.
  • Symbiotic relationships — Broadly defined as relationships occurring between living entities. Although there are several types of symbiotic relationships, for this story, we are looking at one subtype: mutualistic symbiosis.
  • Ecosystem — A community of living organisms in conjunction with the nonliving components of their environment, interacting as a system.

Trees thrive when they live together in a forest. A single tree will struggle to survive on its own, however many trees together create an ecosystem that produces a protective environment in which the trees can live to be very old. Since every tree is a valuable member of the community, trees have developed several ways to support and nourish each other. This is true for trees of the same or different species. There are several ways trees communicate and nourish each other above ground, however we are going to focus on how they do this underground.

Indigenous peoples have long understood that trees communicate with and nourish each other. Only recently have scientists used modern tools and techniques to explain just how this amazing communal network occurs. The most important means of underground communication is by participation in a mycelia fungal network — the relationship between tree roots and the fungal hyphae present in the soil. These hyphae form networks known as mycelium which infiltrate and connect tree roots of the same or different species. Over centuries, a single fungus can cover many square miles and network an entire forest, enabling the sharing of water and nutrients. The mycelial network can also transmit very low voltage electrical impulses to trees which communicates information about insects, drought, and other dangers. This vast underground mycorrhizal network can be thought of as the “internet” of the soil and is often referred to as the “wood wide web”.

Another service fungi provide trees is the filtering out of any heavy metals in soil. These diverted pollutants turn up in the fungi’s fruiting body (i.e. mushrooms). Fungi will ward off bacteria or other destructive fungi that are trying to invade the tree. This tree/fungi relationship can go on for hundreds of years, however if conditions in the environment become unhealthy, the fungi may die out. At that point the tree may hook up with a different fungal species that settles in at its feet. Every tree species has multiple options for mutualistic fungal partners.

I’ve focused above on the benefits a tree derives from its relationship with a fungal partner however, as I mentioned, this is a mutualistic partnership. What is the benefit for the fungi?

Payment for the services the fungi provide to the trees is in the form a nutrition – sugar and other carbohydrates – which the fungi cannot produce on their own. The fungi retain about 30% of the carbohydrates the tree produces, thank you very much.

Some species of fungi are considered “host specific” and will partner only with a specific tree type (e.g. birches or larches). Others, like chanterelles, get along with many different tree types. Underground competition is fierce which works to the benefit of the trees; it is only when all the fungal species die out that the tree becomes vulnerable. Because fungi are dependent on stable conditions, they support a variety of species in order to ensure that one tree species doesn’t manage to dominate. Fungi can store and later share resources (particularly nitrogen and phosphorous) when the soil becomes depleted. In some tree/fungal relationships where the soil becomes depleted of nitrogen, the fungi will release a deadly toxin into the soil which causes minute organisms such as springtails (tiny insects that live in leaf litter, compost piles, and soils) to die and release nitrogen tied up in their bodies, forcing them to become fertilizer for both the tree and the fungi.

Saplings (young trees) growing in a shady area that do not receive enough sunlight to perform adequate photosynthesis often receive assistance from older established trees called “hub trees” or “mother trees” to provide water and nutrients via the mycorrhizal network. Studies have shown that trees can recognize the root tips of their relatives and favor them when sending nutrients. Through the mycorrhizal network, hub trees detect distress from their neighbors and send them needed nutrients. During a recent walk in the coastal forest south of Coos Bay, Oregon I came upon the tree pictured below. I was reflecting on the tortured life this tree must have lived when I look up at the canopy and was amazed to see branches that still had green fir needles — it was still living! Further inspection led me to realize that tree next to it (in the far left of the picture) had a huge root leading right to the crippled tree, most likely providing the nutrients needed for the older tree to remain alive. Quite possibly this younger tree is the offspring of the older tree and demonstrating that both older and younger trees take care of each other as needed.

MAKING THE CONNECTION: People are generally aware of the many benefits trees provide to the natural world including removal of carbon dioxide from the atmosphere, production of oxygen, provision of shade and habitat for numerous species, wood and fruit production, to name just a few. It’s easy for humans to take for granted the gifts that trees provide to our ecosystems. Having a deeper understanding of how trees are able to grow and thrive in community with the help of their fungal friends helps foster greater respect and gratitude for both of these species. Although the mycelial network is largely invisible to human awareness, knowing of its existence and the important role it plays in nurturing our forests is an important connection to make in understanding how symbiotic relationships between species are crucial to maintaining balance in natures ecological processes.  Try to imagine a world without trees. It would be a world vastly different from the one we live in — one devoid of most, if not all, terrestrial life forms.

FURTHER READING AND REFERENCES:

Wohlleben, Peter. The Hidden Life of Trees: What they Feel, How they Communicate. 2015. Germany: Random House GmbH.

Kimmerer, Robin Wall. Braiding Sweetgrass. 2013. Canada: Milkweed Editions.

https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2_053864

https://www.arboristnow.com/news/mycorrhizae-my-favorite-kind-of-fungi

https://preservationtree.com/blog/how-mycorrhizal-fungi-help-trees-communicate

https://sciencing.com/symbiotic-relationship-8794702.html

https://www.nationalforests.org/blog/underground-mycorrhizal-networkhttps://www.scientificamerican.com/article/a-poetic-mind-bending-tour-of-the-fungal-world/

Welcome!

Welcome to my blog. Come on in, grab your favorite beverage, make yourself comfy. My goal in writing this blog is to introduce you to some of the symbiotic relationships found in the natural world that may surprise and delight you. All life is dependent on symbiotic relationships between species. Understanding the interconnectedness found in the natural world will hopefully lead to an understanding of the importance of the earth’s biodiversity and inspire you to set forth on your own path to help nurture and protect our precious ecosystems. Although this topic has the potential to go many directions, and dive quickly into complexity, I keep the relationships presented limited to two or three species or subjects in one post. In order to verify the accuracy of information presented I seek out several reliable sources of information.

I have B.S. degrees in both Geology and Medical Technology and although my working career was in Medical Technology, I have always held a deep interest in the natural world which has propelled me to investigate, observe, contemplate, and appreciate the finely tuned choreography of the natural world. In 2017 I became certified as an Oregon Master Naturalist in order to learn more about the ecosystems in Oregon and to join in the efforts of various local organizations to preserve and protect our natural areas. This blog serves to educate and further inspire both of us.

I acknowledge that you, the reader, may or may not have a scientific background or training, however I make no assumptions that you are familiar with scientific terms that are not in our common vocabulary. You will see that I include a section to define terms, as needed, to help with overall understanding of the discussion. I will also include reference links for those that want to read further on the information presented.

I hope you enjoy reading this blog as much as I will enjoy writing it. Please click the “Follow NATURAL CONNECTIONS” button at the bottom of the page and share the site with anyone you think may be interested in reading the posts. I welcome your feedback and ideas for topics to include in future posts in the comments section.

Carole