Tuesday, January 26, 2021

Scientists investigate distribution of muskrats, beavers, otters in Rhode Island

        A University of Rhode Island graduate student will be scouring lakes, ponds and wetlands throughout Rhode Island over the next three years to search for signs of three semi-aquatic mammals to document their distribution in the state.
        Traveling via kayak, John Crockett will search for evidence of muskrats, beavers and river otters in waterways of southwestern Rhode Island this winter before expanding his search to other areas of the state in the coming years.
        “The main goal of the study is to get a good sense of the distribution of each species across the state,” said Crockett, a native of Fort Collins, Colorado, who is collaborating on the study with URI
John Crockett surveys for muskrats, beavers, otters
Assistant Professor Brian Gerber. “To do that, we’re conducting an occupancy analysis, which means we’re going out looking for signs of tracks, scat, chewed sticks, lodges and sightings of the animals.”
        All three species have been the target of trappers in Rhode Island for many years – though the state legislature banned the trapping of river otters in the 1970s – and most of what state wildlife officials know about the animals is derived from trapping data. But since trapping has been decreasing in popularity in recent years, less and less data about the animals is being collected.
        “We want to make sure we have a good assessment of where these mammals are found,” said Gerber. “It’s been 10 or 15 years since anyone has spent much time looking for them, and we want to see if we find any changes in their distribution since those earlier surveys.”
        Muskrats are in decline across much of their range in the United States, according to Crockett, and now they are difficult to find. The decrease in trapping activity has made it difficult to tell whether the animals are in decline in Rhode Island or if the lack of trapping just makes it appear to be so.
        Since river otters have not been trapped for 50 years, very little is known about their distribution and population in the state. “Ever since the ‘70s, we’ve been mostly in the dark about where they are and how many there might be,” Crocket said.
        Beavers are believed to have recovered well after being extirpated from the area due to unregulated trapping and forest clearing in the 1800s. “Now they are creating conflicts with their dams causing flooding in some places,” Gerber said. “We’d like to be able to identify the habitat features where beavers are doing well and those areas where they are likely to cause conflict. To do that, we need distribution data.”
        Crockett expects to conduct his surveys from December through March for the next three years, as well as periodic summer surveys. He eventually hopes to be able to estimate the probability that any of the three species will be found in a given habitat.
        “Part of what we’re doing is trying to relate their distribution to changes in land use,” he said. “We have pretty good data on how these wetlands have shifted over time, so hopefully we can find some hint of an answer about why these animals’ populations are changing.”
        The URI scientists are working closely on the project with wildlife biologists at the Rhode Island Department of Environmental Management so the data can be used to help prioritize habitat for protection and inform management decisions on trapping limits.
        This is one of two research projects Gerber is leading that focus on learning more about Rhode Island’s mid-sized predators. The other is investigating the distribution and movement patterns of fishers in the state.

Thursday, January 21, 2021

Urban areas need 'freedom lawns' to revive their soil

        Few people put much thought into the soil beneath their feet, but Loren Byrne does. A professor at Roger Williams University, Byrne is an expert on urban soil ecology, and he worries that humans are changing the structural integrity of soils in urban environments and limiting the ability of plants and animals to live in and nourish the soil.
        “Soil is easily overlooked and taken for granted because it’s everywhere,” he said. “We walk all over it and think of it as dirt that we can manipulate at our will. But the secret of soil is what’s happening with soil organisms and what’s happening with their interactions below ground that help regulate our earth’s ecosystems.”
        Byrne contributed a chapter about urban soils to a report, State of Knowledge of Soil Biodiversity, issued last month by the United Nations Food and Agriculture Organization. He discussed how the ecology of the soil changes as it is compacted during construction, paved over, chemically treated for lawns, and dug up and carried away.
        “The main takeaway is that urbanization can potentially harm biodiversity, but our biggest current

threat is ignorance,” he said. “We don’t understand enough about soil biodiversity in urban environments, so we may not be able to manage it in ways to provide the benefits that are possible.”
        Soil is the foundation for terrestrial life, according to Byrne, not only because it is the medium in which plants are grown but because it regulates the nitrogen cycle, sequesters carbon and manages the flow of water. He thinks soils are fascinating because they contain the full range of life on earth, from single-celled bacteria and fungi to animals of all varieties.
        “If you’re patient enough to get down on your hands and knees and pull up some soil, you’ll see mites, springtails, isopods, millipedes, centipedes, spiders, ants, beetles,” he said. “Some of them have negative popular connotations, but ecologically, if we can see them as having value, then that will help us maintain more sustainable landscapes.
        “Changing our perspectives of what these organisms are doing in the ecosystem is important,” Byrne added. “They perform beneficial functions, like decomposition. I tell my students that if it wasn’t for this whole suite of biodiversity in our soils, we’d literally be up to our necks in dead stuff.”
        Although it may seem counterintuitive, Byrne said that urban soils contain the full range of biodiversity that is found in natural soils, and some research shows that they contain more organisms and a greater diversity of organisms than agricultural soils.
        “A lot of urban habitat types, like lawns and little forest patches, are perennial, so they don’t face the same level of annual disturbance as agricultural fields,” he said. “And they have more organic matter in them, so that allows the food web to become more complex. Urban soils are home to a lot of organisms.”
        He noted, however, that there is also a massive volume of degraded soil in urban areas that is compacted, trampled, over-fertilized, and removed and replaced with lower quality soil.
        “It’s a very interesting dichotomy,” Byrne said. “There are some high-quality soils and other locations that have been severely negatively impacted where we would want to somehow improve them.”
        How to improve degraded soils is the topic of Byrne’s latest research. Decompacting the soil and remediating pollution are important steps, but the key is the addition of organic matter.
        “There’s been a wide diversity of organic matter sources that have been investigated, from basic garden compost to sewage sludge to bio-char, which is a burned organic matter that, when added to soil, provides good surfaces for microbes to live on,” he said. “But you have to be very careful about what you’re using and in what contexts and the source, because not all organic matter is the same.
        “A lot of research has shown that adding organic matter will help remediate the soils in various ways. Organic matter holds onto water, so it helps with water issues, for instance,” Byrne added. “But in locations that are already prone to water-logging, adding organic matter could be a bad thing. So context matters. You need to be familiar with site specific issues to come up with a good management plan.”
        Byrne focuses a great deal of his research attention on lawns, which he calls a “human created ecosystem.” While he noted that a lawn provides a nice place for a picnic and is better than pavement, he said installing a lawn is the least biodiverse way of improving urban landscapes.
        “The goal with a lawn is often one grass species that’s bright green and isn’t growing or reproducing, which is the exact opposite of what life wants to do,” he said. “In the grand scheme of all life, a place becomes more diverse over time, it grows and reproduces, and humans are trying to stop all of that in a lawn.
        “The problem isn’t so much the lawn itself as the monoculture, pesticide-managed lawn. A lot of what ecologist’s advocate is a more biodiverse lawn where we let the so-called weeds grow and let the grass grow a little taller. That’s good for the soil ecosystem because a higher variety of plants and no chemical pesticides will allow more soil organisms to thrive.”
        To create a more sustainable urban landscape, Byrne advocates for what some have called freedom lawns – a mowed lawn that maintains a high diversity of grasses and weeds and good soils.
        “If we can convince people that it’s more patriotic to shift to freedom lawns, it will be more sustainable,” he said. “And if we can shrink the area of lawn by creating more biodiverse habitat through shrubs and wildflowers, that’s another step toward sustainability and biodiversity.”

        This article first appeared on EcoRI.org on January 21, 2021.

Thursday, January 14, 2021

Despite their name, blue jays aren't blue

        After the colorful fall foliage turns to brown, it takes a while before Mother Nature offers up another splash of color. Spring brings forth bright green leaves, blooming flowers and birds dressed in their Sunday best, but first we’ve got to get through the dreary colors of winter.
        We occasionally see a bright spot amid the grays and browns in the coldest months of the year – a few purple berries left uneaten by the birds, for instance, or the occasional sighting of a cardinal. But mostly we’re left with muddy ground, dormant trees, and wildlife wrapped in their dullest colors to match their surroundings.
        And then a blue jay jets into our yard and reminds us that another color of the rainbow hasn’t
Blue jay (Paul Dacko)
 abandoned us entirely.
        Except that blue jays aren’t really blue.
        You read that right. The first time I heard about it – in my college ornithology class – I didn’t believe it either. Blue jays aren’t blue? How can that be? I can see their blue feathers with my own two eyes! And yet every scientific reference I’ve checked in the last 35 years – and I double-check every year or so, including this week – tells me it’s still true.
        In the natural world, there are red feathers and white feathers and yellow feathers and black feathers. There are green feathers and brown feathers and even a few purple feathers and orange feathers. But there are no blue feathers. They don’t exist. Anywhere.
        That means that blue jays aren’t blue, and neither are bluebirds. And if you think that an indigo bunting is actually indigo, you’d be wrong about that, too.
        According to every ornithologist and scientist I’ve spoken to – and there have been many – blue feathers are a figment of our imagination. Or as one birder called it, “a pigment of our imagination.” What looks to our brains to be a blue feather is, in fact, a blue-looking color generated by white light interacting with the three-dimensional architecture of the feather. It’s what scientists call a structural color, rather than a pigment.
        Most birds get their colored plumage from pigments in the foods they eat. That’s why many pink flamingos at zoos aren’t very pink – because they don’t get their natural diet of algae and crustaceans that results in their pink feathers. Blue pigments, like those in blueberries, are destroyed when digested by birds.
        According to a Yale University ornithologist, blue feathers are created when the cells inside the growing feather dry up, leaving behind an architecture made of keratin molecules – the same material as our fingernails – containing air pockets like a sponge. When white light strikes it, the keratin structure somehow amplifies the blue wavelengths while canceling out the red and white wavelengths, making the feather look blue. Even though it isn’t.
        Take it away from a white light source or mess with that architecture, and the feather won’t look blue any more.
        Now that I’ve explained the bizarre science behind blue feathers, my advice is to ignore it and appreciate the beauty of those blue feathers – regardless of how they’re formed. We need those splashes of color to help us get through the bleak winter days, and I wouldn’t want to take anything away from your enjoyment of our local blue jays.
        And if you can’t find a blue jay, point your eyes skyward on a cold clear day and take in the bright blue sky. As far as I know, it’s really blue. But don’t quote me on that.
        
        This article first appeared in the Independent on January 9, 2021.

Monday, January 11, 2021

Swamp otters

        It’s mud season in Central New York, and along the edge of a pond created by a massive beaver dam, patches of melting snow are interspersed with ankle-deep mud and seeps of water streaming down from a hemlock-covered hillside. Recently arrived red-winged blackbirds continuously call as Scott Smith slogs along the trail looking for any indication that river otters are in residence.
        “Raccoons are the bane of my existence when looking for otter sign,” says the wildlife biologist for the New York Department of Environmental Conservation, noting the similarity in their tracks after the mud and snow have thawed and refrozen multiple times. But raccoon tracks aren’t the only mammal sign he finds. Beaver are clearly quite active around the impoundment, as are mink, muskrat, deer, fox and coyote.
        At an opening beneath an alder thicket, Smith finds what he’s looking for. What looks to the uninitiated like a two-day-old pile of vomit is in fact what Smith calls an otter toilet – piles of fish

River otter eating a fish (Mary Holland)
scales mixed with fecal matter, all clearly smelling like fish. Its location next to open water and beneath shrubs make it what Smith says is a typical toilet site.
        “I’ve seen enough of them that this situation usually means a toilet,” he says. “I’ll look at 47 of these and not find anything, and then there it is. It’s a pull-out area to rest, eat, toilet. Often I’ll find a half-eaten fish in there.”
        During the next half hour, Smith finds additional otter toilet sites at similar locations around the pond, as well as on top of fallen logs and on several beaver lodges and muskrat dens. “There’s an advantage for otters living around beavers because it provides them with habitat, den sites, and resting sites,” he says. “I’m not sure there’s an advantage to the beavers, other than that otters are alert for predators and chirp a lot.”
        Smith’s hunt for signs of river otter activity is part of a region-wide survey to learn how well the animals have re-established themselves in central and western New York after reintroduction efforts in the early 1990s. Otters were extirpated from much of the region in the 1800s and early 1900s due to unregulated trapping, the clearcutting of forests for farming, and the growth of industrial activity that degraded water quality. In the years since, forests in the region have rebounded and water quality has improved.
        Although transient otters from nearby Pennsylvania – or perhaps from the Adirondacks or Catskills regions – would occasionally find their way to the area, Smith says it would have taken a century for the animals to re-colonize the area on their own. To speed up the process, a group of private citizens worked with the state legislature to establish the New York River Otter Project and fund the reintroduction of otters. Nearly 280 river otters were captured in the Adirondacks and Catskills and relocated to 15 sites in central and western New York over a three-year period in the 1990s. Twenty-five years later, Smith and his colleagues conducted two years of monitoring surveys at 1,200 sites across the state to assess how well the population was doing.
        “River otter are not easy to count because of the habitat they’re in and their elusive nature,” he says. “With fisher, you can throw a hunk of meat on a tree trunk and put a camera trap up and document them easy. We can’t do that with otter. And you can’t see them with aerial surveys.”
        It took several years of trial and error to find an adequate survey method, but once they did, they found that otters had successfully re-colonized most of the available habitat in the survey area.
        “We realized that river otters are misnamed,” says Jacqueline Frair, a professor at the SUNY
Scott Smith searches for signs of otters (Todd McLeish)
College of Environmental Science and Forestry in Syracuse, who led the survey project. “They should be called the swamp otter. They like marshes and swampy backwaters more so than big rivers and big lakes. When they were released at the edge of big lakes, they moved to find a better place.”
        Smith agrees, though he adds that forests are critical otter habitat, too. “Forests help filter out contaminants before they get into the wetlands. And otters travel a lot through forests. They go up one watershed, take off cross country over hill and dale and drop into the next watershed.”
        According to Frair, the river otter survey was launched to collect data so a statewide wildlife management plan could be prepared for the species. Because trapping of otters is prohibited in the area where the animals were relocated, harvest data was unavailable to compare with other parts of the state.
        “We wanted to figure out whether they’ve recovered, and if so, what should our management goals be for them,” she says. “The state is responsible for opportunities to use these resources wisely, so one underlining question is whether they’ve gotten to the point where there are opportunities for trapping, or at least, can we release some of the restrictions we’ve put on beaver trapping in the area because otter can handle incidental losses.” (Beaver trappers occasionally capture otters by mistake.)
        The otter recovery took longer than most people would have guessed. Some thought the animals would be highly visible everywhere they looked by now, but otters typically avoid areas where human populations and road density are high, Still, the scientists believe otters have reached the carrying capacity of their habitat across much of the region.

        River otters are larger than most people imagine, growing to 4 feet long (including their tail) and weighing more than 25 pounds. Despite their name, they spend only about half their time in the water but are seldom far from it. They feed primarily on fish, frogs and crayfish, though they’ll consume almost any marine invertebrate, and they den in banks along rivers, especially sites with entrances below water. Females give birth to three or four pups every year in late April or early May, and the pups are independent within six months, though some will remain with their mother through the winter and disperse the following spring.
        They are tenacious animals that can defend themselves against most aggressors. “Coyotes could pick off a few, bobcats maybe too, but the young are the most susceptible,” Smith says. “Once an otter becomes an adult, they’re pretty resistant to most predation. The bigger threat is roadkill. They don’t seem to have the gift to look both ways before crossing the road.”
        Despite facing similar issues as the otters in central and western New York, river otters in most of the rest of the Northeast never disappeared entirely – though their numbers were depressed in many places in the late 1800s and early 1900s. Now they are somewhat common just about everywhere. In the Adirondack region of New York, the ample protected habitat and limited timber harvesting kept river otter numbers high even during the population declines in other parts of the region. The rugged terrain reduced opportunities for farming and development, so water quality has remained high for otters that are known to have a low tolerance for polluted water.
        “The big difference between the Adirondacks and the rest of the state is that we’ve just got so much habitat,” says Tim Watson, the state biologist who monitors river otters in much of the Adirondacks. “We’ve got lakes and rivers and beaver ponds spread out all through our 6 million acres, so we have a lot of habitat that can support higher densities of otters. And we’ve got a lot of areas that are inaccessible to trappers.”
        The situation in northern New England is similar, with the state biologists there declaring their otter populations abundant thanks to plentiful undeveloped river systems, lakes and tributaries. Along the Maine coast, river otters have even been observed preying on rare seabirds on coastal islands in recent years, proving that the animals occasionally spend time in salt water.
        “River otters are a fascinating species,” says Patrick Tate, a wildlife biologist for the New Hampshire Fish and Game Department. “They seem to thrive in dark tannic water where they hunt bottoms and edges using their whisker sets located on their chin and nose area. While some otter are taking advantage of our dark-watered – though clean – beaver flowages, others have occupied New Hampshire’s largest lakes and river systems.”
        Southern New England experienced considerable deforestation for farming, as well as industrialization, in the 1800s that affected water quality, and while otter numbers declined precipitously a century ago, they aren’t believed to have ever been extirpated. Today they can be commonly found in most available habitat. As elsewhere, they have benefitted greatly from the presence of beavers and beaver ponds and whatever other waterways support their preferred prey.
        Every state in the region except Rhode Island uses trapping as a way of managing and monitoring river otter populations. Harvest numbers are relatively low in most areas, ensuring that the harvest is sustainable. Massachusetts reported just 35 animals trapped in all of 2019, and the average otter harvest in Maine over the last 10 years has been approximately 600 animals. Because fur prices vary considerably from year to year, which causes great fluctuations in trapper effort, biologists in Maine are seeking new tools for assessing otter numbers and managing the population of furbearing animals, including camera traps, environmental DNA surveys and citizen science projects.
        The trapping situation in Rhode Island is unique. Trapping of river otters in the state has been prohibited since 1970, when a state legislator apparently observed the illegal shooting of an otter and subsequently succeeded in passing legislation to ban otter trapping. Despite several efforts to overturn the ban through the years, it remains in place, making Rhode Island the only state east of the Mississippi to prohibit river otter trapping, according to state biologist Charles Brown.
        Whether trapping will be permitted in the coming years in central and western New York, where the animals were reintroduced in the 1990s, will depend on the outcome of the management plan being prepared by the state.
        “They’re very cautious about saying ‘otter are recovered, so let’s hunt them,’” Frair says. “But collectively we’re comfortable with the comparisons we’ve made about where they’ve recovered and where they’ve had sustainable harvests. We know populations can sustain harvest, but we’re not going to immediately open the area to harvest. They’ll probably monitor them again first. We want to see how sensitive our methods are to being able to detect changes in the population.”

        Back at the beaver pond in central New York, Scott Smith stands atop the sturdy beaver dam and gazes across the water at an abandoned beaver lodge, which he believes is where the family of otters is living. Judging by the number of otter toilet sites he found during his survey, he guesses that a family unit of otters – a female with kits – is spending the winter there.
        “They’ve probably been hunting here all winter,” he says. “Fewer toilets would mean that this is probably just a travel link between other habitats. But I think we’ve got a family here. The fish scales we’re seeing are small, so they’re probably eating minnows, but larger scales might indicate they’re eating bass or carp or sunfish. You can tell their main prey base by looking at the scales in their scat.”
        Smith drives a quarter mile north to more stream-like habitat leading into the beaver impoundment, where he finds several muskrat dens, each topped with otter scat.
        “We definitely have a good conservation success story to tell here,” he says.

This article first appeared in the Winter 2020 issue of Northern Woodlands magazine.

Friday, January 8, 2021

Camera system could protect endangered whales

        The beginning of the calving season for North Atlantic right whales, one of the rarest marine mammals on earth, is looking promising with four newborn calves observed in December. But the outlook for the species, whose global population is estimated at only 360 individuals, remains grim. Between fishing gear entanglements and collisions with ships, more whales have died in recent years than were born.
        A new technology on the horizon may help to reduce one of those threats, however. A smart camera system invented by a team of scientists and engineers at the Woods Hole Oceanographic Institution is being tested in local waterways and could be deployed on vessels traversing the East Coast to reduce the threat of ships striking right whales.
        “The idea is simple,” said Woods Hole Assistant Scientist Daniel Zitterbart, who is leading the
North Atlantic right whales (WHOI)

project. “We took a commercial thermal imaging camera, highly stabilized for roll and pitch, and a computer algorithm that looks at images and tries to tease out what’s a whale compared to what’s a wave or a bird or whatever.
        “The key part is, if you’re in a large vessel and you know there’s a whale 300 yards in front of you, it’s probably too late for you to turn away from it,” he added. “Our aim is to push the detection range as far as we can, which makes things difficult on a rocking boat. But getting the range we need to make a difference for the animal is the objective.”
        A prototype of the smart camera system was tested last summer on a research vessel in Stellwagen Bank National Marine Sanctuary in Massachusetts Bay, about midway between Gloucester and Provincetown, where humpback whales congregate to feed each year. A similar land-based installation was also deployed at a busy shipping channel in British Columbia traversed by endangered Southern Resident killer whales. The initial tests were promising.
        “If you’re talking about very large vessels like tankers or cargo vessels, they may not be maneuverable enough for the detection ranges we get, but for cruise vessels, ferries and fishing vessels that are more maneuverable, it definitely can make a difference,” Zitterbart said.
        A little larger than a half-gallon milk carton, the camera system must be installed at least 15 feet above the water line to be effective. Within seconds, it can detect the presence of whales a mile or more away and alert the captain in time for the vessel to slow down or change course.
        Unlike human observers or spotter planes, which are occasionally used in the U.S. and Canada to watch for right whales and alert nearby ships, the camera system can spot whales in daylight and darkness with little effort.
        James Miller, an ocean engineering professor at the University of Rhode Island, invented a forward-looking sonar device about 20 years ago that could be used to detect whales, reefs and other obstacles to navigation beneath the water’s surface. He commercialized the product by founding FarSounder, a Warwick-based company with clients around the world. The company’s sonar devices can scan up to 1,000 meters in front of a ship moving at speeds of up to 25 knots to detect underwater obstacles.
        “Dr. Zitterbart's technology for detecting whales at the sea surface can be an important part of the solution for reducing ship strikes, one of the leading causes of death for large whales,” said Miller.
        Zitterbart said that sonar is a better detection method for sensing static objects beneath the water’s surface, but he believes his thermal camera system is more effective at detecting moving objects like whales that may only be noticed for a few seconds. Both technologies can be hampered by challenging environmental conditions.
        The recipient of the 2019 Young Investigator Award from the U.S. Office of Naval Research for his work on whale detection, Zitterbart previously developed a thermal imaging system for protecting whales and other marine mammals from underwater noise produced by the air guns used in seismic surveys.
        Assuming his tests are successful this year, Zitterbart plans to deploy his camera system on a number of vessels without his development team aboard to ensure that remote troubleshooting can be conducted effectively. Eventually, he hopes to find a company interested in commercializing the technology.
        “Thermal imaging systems are a powerful new tool in real-time whale detection,” he told Ocean Insights. “Used alone or in conjunction with acoustic monitoring, this technology could significantly reduce the risk of vessel strikes.”
    
        This article first appeared on EcoRI.org on January 7, 2021.