New England Cottontail Rabbits

Note: This program first aired on January 16, 2016.


Join me in a thought exercise for a moment. Think of the most beautiful landscape you can imagine, one worthy of protection in perpetuity, one that meets all of our emotional, physical and spiritual needs. You may have conjured up an image of a mountain with a waterfall, a babbling brook, an open forest. Maybe a woodland or grassy savannah with a view from a high point. There are endless possibilities. One image I can almost guarantee you did not picture is a low shrub thicket tangled with thorny brambles and vines, with 20,000 to 50,000 stems per acre, virtually impossible for a human to walk through. But if you were a New England Cottontail Rabbit, this is exactly the landscape you would be imagining.

New England Cottontails are Maine’s only true rabbit, and Maine’s only state listed Endangered terrestrial mammal (the Snowshoe hares who’s tracks we see everywhere in the winter are different). Historically these rabbits lived throughout New England from just west of Penobscot Bay all they way to the Hudson River, down to Long Island. New England Cottontails became an Endangered species in Maine (and qualify for various levels of protection in the rest of New England) for one big reason, habitat loss. Since 1960 habitat for New England Cottontails has declined over 80% across its range. All animals are dependent on the environment to provide for their physical needs, habitat provides shelter from the elements, protection from predators and a supply of food. New England Cottontails are specialists when it comes to habitat requirements, they are adapted to be need very specific attributes in the places they call home. And those attributes include dense vegetative cover composed primarily of woody shrubs and small deciduous trees 3 to 15 feet tall, in patches of 10 to 25 acres. Size and structure.

The problem is that we don’t have very many stable shrublands here in New England, meaning, shrubs generally aren’t a climax vegetative community. These thickets primarily form as a result of landscape disturbance, they are what is called in ecological terms “early successional”. After a forest clearing disturbance the first plants to come in and colonize the disturbed area tend to make a dense thicket of herbaceous material, shrubs and sapling trees. This community only lasts 20 years at most before the tree saplings grow tall enough to shade out the understory, which opens up the thicket and degrades the habitat for the New England Cottontails. Which means, in essence, New England Cottontail rabbits are a disturbance dependent species.

The reason that they are now in decline is that we humans don’t like disturbance very much, nor do we appreciate landscapes that change over time. New England Cottontail rabbits got a temporary boost when agriculture declined in Maine, and thousands of acres of fields transitioned from open hay or cultivation back to forest. Initially the regrowing fields provided perfect thicket habitat, but then ecological succession continued, and the thickets were replaced by young forest. Additionally, we actively suppress fires, cut dead wood and otherwise manage forests to minimize disturbance and maximize the development of multi age climax forest stands. Essentially we do everything we can to prevent the kind of disturbance that will create new habitat for the New England Cottontail; we fanatically mow to keep open land open, and actively encourage the development of forests, dismissing all the messy swampy shrubby stuff that comes inbetween. We are effectively holding the landscape static, when static is exactly what natural landscapes are not. In doing so, we have a significant negative impact on organisms that are dependent on this ephemeral natural community; the New England Cottontail may be the most charismatic of the bunch, but over 100 other species of special concern share the same habitat requirements, suffer the same declines at the loss of habitat, and enjoy the same benefits of active habitat restoration.

Restorative action is taking place in all of the 5 remnant populations remaining in the rabbits’ historic range. Landowners are working with state and federal officials, doing things that seemed unimaginable to the conservation minded citizen years ago, clear cutting small tracts of forest, mimicking the natural small scale disturbance caused by low intensity fires, beaver flooding and wind storms, allowing patches of early successional habitat to flourish. This is truly “next level” conservation, working with natural patterns over both time and space to create a dynamic long range management plan that honors all species, not just the climax community ones. Sometimes it just takes a cute little bunny to get us there.

From US Fish and Wildlife Service

References: 

Federal US Fish and Wildlife http://www.fws.gov/northeast/newenglandcottontail/pdf/NEcottontail2015.pdf  

Learn everything you wanted to know about New England Cottontail Rabbits: http://newenglandcottontail.org/

Maine Dept. of Inland Fisheries and Wildlife: http://www.maine.gov/ifw/wildlife/species/mammals/endangered.html

 


 

Succession and the Bucksport Mill

Note: This program first aired October 11, 2014.

 

If there is anything you can be sure of in nature, it is that things will change. The natural world is not static and nothing remains untouched by this truth. As soon as mountains are formed, they begin to erode. The temperature falls and rises, ice covered this landscape, not once but many times, the ocean has left its mark too. Forests we experience as known communities are as ephemeral as spring flowers, in the grand scheme of things here on Earth.

Knowing this truth of the world did not make this week’s news from Bucksport any easier to hear. The paper mill that opened there in 1930 formed the economic and social backbone of Bucksport and many neighboring towns. The paper mill that will be closing there at the end of 2014, 84 years later, leaves a hole not only in the tax base but also in the fabric that stitches that community together.

The make up of a natural community is determined by many factors, the most fundamental of which are the external environmental conditions present. If the climate is cold, we expect to see cold adapted plants and animals, if the climate is dry, we expect to see succulent plants or fire adapted plants. When the environmental conditions change, we expect to see the ecological community change as well. On a landscape freshly cleared, whether by wild fire, glacial melt, sea level drop or some other disturbance, we see the successive changes in community composition coming in an orderly procession; fast growing opportunistic species first, more slow growing and complex assemblages later. In classical ecology we are taught to recognize the climax community, the culmination of successional change that started with our blank slate, and progressed to a fully articulated rich and diverse ecological community. The implication is that once climax community is reached, it is self sustaining unless environmental conditions change, thus changing the playing field and potentially favoring species other than those on the climax community cast list.

My father worked at the mill for 22 years, in it’s hay day, when all four paper machines ran twenty hour hours a day, the employee parking lots so full we might not be able to see Dad’s car when we drove by on the way to my grandmother’s house, when men and women took what now seems an old fashioned pride in their work, when unions fought for workers rights and won. That mill lifted my family from the threshold of poverty, gave me amazing health insurance, put my sister and me through college. It was not easy work, but making paper provided a living that supported countless families year in and year out.

Red oaks dominate the forest around my house, they are the prevailing species in the Oak and Northern Hardwood forest climax community that typifies my neighborhood. They provide food for thousands of creatures, insects that feed as parasites on the growing acorns, grackles and blue jays who eat acorns right off the tree, the myriad of forest animals large and small who eat the acorns once they fall to the ground. These animals depend on this tree in an existential way, if these oaks were to die out due to changes in the environment, these animals would need to adapt to a new way of life, new food sources, a new community in an old place.

Bucksport sits now right on the edge of the end of its climax community. Much like we see the changes ahead due to climate change, Bucksport must ready itself for a fundamental shift away from the very thing that has been the organizing structure for the town for the past 84 years. By nature’s clock that isn’t a very long time, but its long enough for a field to turn into a forest. Perhaps the grasses mourn the loss of the sun when the first woody shrubs grow above them and spread their leaves. Perhaps the shrubs cry out their loss when the mighty oak’s branches cover the sky. Change is the only thing worth betting on, we can’t hold the natural communities around us frozen in place any more than we can keep a mill from closing, though it may break our hearts to see it go.

It’s been 16 years since my father died, and the mill’s death spiral started not long after, machines were shut down, shifts were cut. The parking lot got smaller. The truth is, this has been coming for a long time, just like the changes in global climate we as a society, are doing our best to ignore. And just like communities in nature, a new reality will grow in Bucksport, one calibrated to the economic and ecological conditions dictated by not only life in the 21rst century, but by the very people who call that place home.

References:

Want to try your hand at keying out Maine’s different natural communities? Check out this classification key: http://www.maine.gov/dacf/mnap/features/communitykey.htm

My home ecosystem: http://www.maine.gov/dacf/mnap/features/communities/oakpineforest.htm

Living in a cave and missed the news? http://bangordailynews.com/2014/10/01/news/hancock/verso-mill-in-bucksport-to-close-by-years-end-570-to-lose-jobs/

Blue Jays and Hunger

Note: This show first aired September 27, 2014.

 

I have red oaks around my house, which means this time of year, I have blue jays. I watched them the other day from my desk, looking out my window at the rain. They hopped and flapped from branch to branch at the top of the trees I see from my third story vista, searching for acorns, their preferred food this time of year. Hence the correlation: oaks and jays. Spending time beneath these branches is a bit of a risk, acorns frequently rain down, dropped accidentally. Jays hold the acorns in their claws and pound away at them with their thick beaks, cracking them open to access the nutritious nutmeat inside. This time of year, it’s likely to be all that they are eating.

There’s a reason we humans think about eating all the time. In the natural world, in the world we evolved in as animals (the animals we still are despite our computers and phones and refrigerators), what else is there to think about except finding food? Food is the constant vocation for wild animals, the number one job of all consumers is just that, to eat. Without enough food, there is nothing, no energy to run the metabolism that drives the fulfillment of genetic destiny. Food first, sex later.

I imagined what that would be like, to wake up in the morning like a wild animal, each and every morning of every day of your life thinking about food. Everyday a new day, a fresh opportunity to eat, or starve. Imagine getting out of bed in the morning in a house with no kitchen. No cupboard, no fridge, no food stores of any kind. Your day starts with you going outside to find something to eat. Every day starts that way. Reality TV aside, this is a marginal existence, an existence that honed us through natural selection oh so many years ago. An existence we pay no attention to now, unless you are a neo-aboriginal, experimenting with “rewilding light”, or desperately poor.

It turns out that Blue Jays, though they live the life of wild creatures everywhere, have a strategy for food scarcity, a strategy to cushion the pangs of hunger. They cache food, acorns and other mast crops from the forest. They can move hundreds of acorns a day, thousands a week, hundreds of thousands during a season. They bury them in small groups in the soil of the forest floor, and have a retrieval rate, according to one study, of about 30 %. That leaves about 70% for other animals to eat, or to germinate, dispersed so widely and nicely from the parent tree. Other studies show that Blue Jays are real foodies, picking only the healthiest and most viable acorns for caching, which means in practice, oak trees have come to depend on this noisy bird for dispersing their seeds. The idea is out there that Blue Jays are at least in part responsible for the rapid reforestation that occurred after the last of the glaciers left New England twelve thousand years ago. That’s a mighty job for a small blue bird. Americans are estimated to waste about 40% of the food we buy, and our food waste doesn’t feed other animals or grow forests, most of it rots in land fills (compost piles not withstanding). It’s a statement of how far out of the system we’ve come.

If I can’t think of the Blue Jays as facing each day with an empty belly (though in practice, even with food stored away, there are not guarentees), there are certainly other animals that wake up each morning with a clean slate. The coyotes I have been hearing around my house every night for the past two weeks don’t cache food. They spend all their time searching. What if I lived more like a coyote instead of a blue jay? What if every day that dawned was a brand new challenge to fill my stomach, as unconnected from the day before as to the day ahead. Each day an individual exercise in survival, life a series of these days strung together, one after the other, going on until I fail.

The blue jays I see this fall I watched fledge in July. Fledging day dawns with a ruckus coming from those same tree tops outside my 3^rd story window, the young hop and flutter from branch to branch all the while encouraged by the screeching calls of the adults. I imagine they are saying “come on come into this world, where your pursuits must be single minded, and your eyes clear”.

References:

Blue Jay basics from Cornell: http://www.allaboutbirds.org/guide/Blue_Jay/lifehistory

Birds of North America Online: http://bna.birds.cornell.edu/bna/species/469/articles/introduction?__hstc=75100365.3158294d7b302ccb4baa709ab0dcc6f9.1397130536637.1402758359782.1411606172833.6&__hssc=75100365.1.1411606172833&__hsfp=1771447269

Good citations to studies if you are a paid subscriber to the Birds of North America site

Nice article with a few more details about cache retrieval rates (presumably from the above studies) http://www.courierpress.com/lifestyle/blue-jays-cashing-in-on-caches-to-survive

Natural History piece from Loyola University: http://www.loyno.edu/lucec/natural-history-writings/blue-jay-acorn-planters

Beloved Summer Insects: Deerflies

Note: This program first aired on August 2, 2014.

This week’s show is dedicated to WERU’s own News Editor, Amy Browne. I happen to know, from social media, just how she feels about the animal we are going to talk about today, though I also know from experience, she’s not alone.

The animal, the bane of existence for so many people, and so many companion animals this time of year, is the deer fly. The common name Deer fly refers to a group of animals in the genus Chrysops, of which there are about 100 species in North America alone. Deer flies are in the insect order Diptera, with all the other flies, in this case their common name is not a trick. It is the females that cause us so much grief. They require a blood meal from a vertebrate to ensure viability of their eggs. Males sip nectar from flowers, (like male mosquitos) for their sustenance. Deer flies (and their closely related bretheren Horse flies) are universally referred to in the literature as having “knife like” mouth parts. They achieve the required blood meal by slashing away at the flesh of the victim, causing a generalized bleeding, which they then slop up with their “sponge like” mouth parts. This part of the story you know well, if you spend any time outside in Maine in the summer.

I wanted to know more about these extremely annoying creatures, so I dug in a bit to see what I could find. And it turns out it is much as I suspected. They are hydrobionts, meaning they need wet areas in which to breed. The females, after their blood meal, lay their eggs on the underside of leaves in the understory or in swamp areas, above damp or wet ground. When the eggs hatch the larvae that emerge drop into the wet ground below and burrow in, living on detritus or as predators of smaller insects and worms. The larvae are active all winter, below the frost line apparently, and after feeding all winter they apparently pupate in early spring for a few weeks. The adults emerge in summer and live from one to two months, tormenting me and Amy Browne and our dogs, and anyone else foolish enough to be outside in wet areas when the temperature is warm enough. One of the sources I found indicated a minimum temperature range of 72 degrees F, but I know that to be incorrect, at least for the deer flies here in Maine. If I can get out before the temperature hits 60 degrees I know I will miss most of them, but above that, they are good to go. They are also primarily visual predators, attracted first and foremost to dark objects that move. If I wear a light colored shirt on my morning run I am much less bothered. My large black thin coated dog however, has no such choice. Sources say that scent and other biological cues like carbon dioxide are also attractants, but my experience leads me to believe the idea that they are primarily visual. It seems that their job in this world is to bite, and bite well, much to our chagrin.

Isn’t that the job of every animal? Every organism? To do whatever it can to carry on and pass on its genes? It is easy to disparage a biting insect that bothers us for one to two months a year, but we have to remember that everything has a job in an ecosystem. The job of many of the deer fly eggs is to get parasitized by wasps. The job of many deer fly larvae is to get invaded by bacteria and fungus and other microbial parasites. The job of many an adult deer fly is to get eaten by swallows and flycatchers and predatory insects like dragon flies and hornets. The job of the ones that survive is to reproduce, and to do that, they need us, or our dogs, or our livestock, or more likely, the large vertebrates that populate the north woods.

No body likes hanging out with deer flies. But all the same, I prefer a world where they exist, a world as full as it can be with as many different kinds of organisms as possible, a world rich and damp and squirming with life. That is truly the point of it all, and we can’t do it without the biters and scratcher anymore than we can do without the cute furry babies and the fluffy little birds. They all count, every last knife like mouthpart wielding one.

References:

More good stuff from Bug Guide: http://bugguide.net/node/view/11387/bgpage

Here’s a whole bulletin about them from the Maine Forest Service: http://library.umaine.edu/MaineAES/TechnicalBulletin/tb160.pdf

Good photos: http://entnemdept.ifas.ufl.edu/creatures/livestock/deer_fly.htm

Microbiome Part 5: Decomposers

Note: This program first aired on Saturday October 13, 2012.

No one really knows how many bacteria are on the Earth. People have come up with models and sampling protocols to try to determine how many individual bacterial cells are on Earth (five million trillion trillion), how many species are in any given proverbial teaspoon of soil (five thousand or more), and how many different species exist globally (a few thousand to a billion). Many scientists believe that the bacterial biomass on the planet far exceeds the biomass of all other living things. Needless to say, there is little consensus and much research needs to be and is being done.

Taxonomically, bacteria make up the roots of the tree of life. They had the planet to themselves for nearly 2 billion years, and then single celled eukaryotes and multicellular eukaryotes (us included) came along and stole the spotlight. We’ve talked before about the photosynthetic role of bacteria, but they have another equally or even more important ecological role on the planet. Bacteria, along with fungi are the great decomposers of our world.

Decomposition doesn’t sound like a very fun job, and to our sensibilities, it often doesn’t smell very good. It is incredibly important however, to the cycling of nutrients and raw materials of life. There are two major biochemical reactions that drive life as we know it (with of course, a few exceptions). The first is photosynthesis; plants use the energy of the sun to take simple molecules and turn them into more complex molecules. In doing so, they store some of the sun’s energy in the bonds that hold those complex molecules together. Simple to complex. The second major biochemical reaction is respiration. All organisms respire, meaning, they take large complex molecules and break them down into smaller simpler molecules, in the process gaining the energy that was stored in the bonds of those large molecules. This is what we do when we eat. This is why plants photosynthesize—they don’t do it for us, they do it to make food for themselves (we just happen to get it before they do in some instances).

Organisms that eat are also know as heterotrophic, hetero meaning different, trophic meaning eating, so heterotrophs eat food that is different from themselves (by comparison, photosynthesizers are autotrophic—they self feed). Heterotrophs have essentially two options for eating; they can ingest food and digest the complex molecules internally, or they can keep the food outside of them selves and digest it externally, absorbing the molecules only once they have been at least partially broken down. We are of the former type, we ingest our food, secrete acid and enzymes, and with the help of some bacteria, liberate nutrients and energy from that food. We don’t however, get all of the nutrients or energy from our food, not close. The classical ecological number is 10 percent, as in only 10% of the energy from one trophic level gets passed on to the next one, the other 90% is lost as waste (in the form of heat and feces). The reality is that this number varies quite a bit with different feeding levels, but the take home message here is that most of what we eat doesn’t actually get into us. My personal theory about why this is has to do with the difficulty of digestion. Our body has to work quite hard to chemically break down those big food molecules. If we work too at it, we might just start to digest our own bodily tissue—that is one of the roles of mucus in the digestive track, to protect ourselves from our own digestive enzymes.

Bacteria are of the latter type. They are external digesters, excreting digestive enzymes to break down food molecules (both large and those that are partially digested and excreted as feces) and then absorbing the smaller molecules that result. Again, I am not a microbiologist, but my personal theory on this is that bacteria, being prokaryotic, lack a nuclear membrane and have their DNA loose inside their cells. I expect that it is to their advantage to not in any way jeopardize their genetic material by having digestive enzymes also floating around inside their cells, hence, external digestion. Fungi, the other group of great decomposers also digest externally and this pattern leads me to believe that breaking down these larger molecules into smaller inorganic nutrients may be a rather harsh process, which is why both decomposers do it this way.

We’ll continue this discussion about the ecological role of bacteria next week as we look in more detail at the specific nutrients that bacteria are so vital in keeping in play in the biosphere.

References:

From the master himself: Stephen Jay Gould, "Planet of the Bacteria," Washington Post Horizon, 1996, 119 (344): H1 http://www.stephenjaygould.org/library/gould_bacteria.html

The factoid about the microbial biomass making up the largest single carbon sink came from this author, but to be honest, I read it on Wikipedia…I’m not proud. Fenchel, Tom (1998). Bacterial biogeochemistry : the ecophysiology of mineral cycling (2nd ed. ed.). San Diego: Academic Press.

Just for fun: io9.com/5908318/10-surprising-things-that-bacteria-like-to-eat

“First-Ever Scientific Estimate Of Total Bacteria On Earth Shows Far Greater Numbers Than Ever Known Before” Science Daily, 1998 http://www.sciencedaily.com/releases/1998/08/980825080732.htm