We live in fast paced times where the human definition of long term is often next month. But the ecological and evolutionary processes driving biodiversity play out over periods ranging from decades to millennia. Part 1 of this series discussed the what of biodiversity – what it is and the challenges in defining and measuring it. In Part 2, we’ll discuss how of biodiversity – how it emerged and how it has changed over past millennia.
How did biodiversity come into existence? What drives it?
Biodiversity – the variety of life on this planet – is not constant or static. It is always changing – contracting, expanding, moving, changing. Three fundamental processes – evolution, dispersal, and extinction – drive life’s variety (Figure 1). But these processes operate over long periods of time to shape the species and ecosystems we see today. Understanding the long view of biodiversity, therefore, is important for our understanding of current patterns and trends around us.
Evolution, extinction, and dispersal are inter-related and subject to various ecological feedbacks and species interactions, especially human interactions (Figure 1). Chance and historical contingency also play a role through random events affecting evolution’s fundamental mechanisms of mutation, genetic recombination, and genetic drift. Let’s start with dispersal.
Dispersal. Dispersal is a key ecological mechanism in response to competition between parent and offspring for limited resources. Dispersal allows for the colonization of new habitats with new resources. Patterns of dispersal depend on a variety of factors and combinations, such as temperature, precipitation, altitude, soils, geography, aspect, and other species.
As the population of a species increases, it spreads out to exploit new habitats and food resources. This results in a number of separate populations in different habitats, so-called meta-populations. Even though they initially contain the same species, these meta-populations may be prevented from interbreeding because of geographic separation or physical barriers (allopatric populations) or differences in behavior, phenology, or other non-physical isolating factors (sympatric populations). Eventually, these separate populations may differ sufficiently from each other to trigger the evolutionary processes discussed next.
Evolution. Evolution is the main engine behind biodiversity. Through the evolutionary process, as illustrated in Figure 2, new species arise, beginning with the dispersal of a species across a number of meta-populations as described above. Eventually, these meta-populations may diverge and form new species through the processes of adaptive radiation, speciation, and natural selection.
Extinction. One may not think of extinction as a driver of biodiversity, but species extinctions often create opportunities in the form of open habitats and available resources that other existing or new species can take advantage of overtime. However, extinctions, particularly mass extinction events, can set off a complex and uncertain chain of events with a number of effects on evolutionary processes, ecosystem structure, and ecological functions (see Erwin, 2000).
A certain level of extinction is a natural part of life; some species succeed and some fail to adjust to a changing environment. Background or “natural” extinction rates (i.e., rates existing before humans) are typically measured in units of extinctions per million species per year (E/MSY). Various estimates of the background extinction rate range from 0.1 to 2 extinctions per million species per year (Pimm, et al., 2014). In Part 3, we will see that estimates of current and projected extinction rates as influenced by humans are exceeding this background rate by orders of magnitude.
How has biodiversity changed over time?
Over millions of years biodiversity as waxed and waned, starting with rapid growth during the Cambrian explosion over 500 million years ago —a period during which nearly every phylum of multicellular organisms first appeared (Gould, 1989). Since the Cambrian, biodiversity has increased dramatically, albeit suffering periodic, mass extinction events (Figure 3). Five major mass extinction events and a number lesser extinction events have occurred over the last 500 million years (Box 1).
The Big Five mass extinctions significantly exceeded the background extinction rate and were believed to be caused by natural events (since humans did not yet exist), such as natural shifts in the climate, volcanoes, meteors, habitat changes, competition, and atmospheric changes.
Following each of these events, the level of biodiversity took approximately 10-20 million years to recover to its pre-extinction event diversity levels. As we shall discuss in Part 3, a number of scientists argue strongly that we are currently in a sixth mass extinction event, driven not by natural causes but by human-induced ones.
In Part 1 we noted the challenges with measuring biodiversity. Measuring biodiversity in the past faces its own measurement challenges. It critically depends on the fossil record and the ability of paleontologists to discovery and classify those fossils. As we know, the fossil record is fragmented and incomplete. Measures of biodiversity based on the fossil record are subject to sampling bias, how fossils are counted (by species, genera, family), and the “pull of the recent” (the better sampling of more recent species). But as more fossils are being discovered, and more sophisticated statistical techniques used, the general shape of the biodiversity curve over time remains similar to the one above.
Box 1: The “Big Five” Mass Extinction Events
But scientists still retain a healthy skepticism as to the precision and accuracy of these measurements.
What does this long view tell us about today’s patterns of biodiversity? Evolutionary forces in combination with the physical environment has established some general patterns with regards to biodiversity.
First, biodiversity tends to increase from the poles to the equator. This is largely due to the greater productivity of ecosystems in line with more precipitation, increasing moderation in seasons, and increased solar radiation as you approach the equator.
Second, biodiversity on land is thought to be up to 25 times greater than ocean biodiversity. On land, forests harbor most of Earth's biodiversity and within forest types, tropical rain forests are the most biologically diverse. In addition, the Earth’s terrestrial subsurface contains a substantial amount of biomass and diversity (McMahon and Parnell, 2018).
Finally, a general principle of ecology is that the larger the area the more species it contains – known as the species-area relationship. This relationship is largely a factor of a greater range of resources, abiotic heterogeneity, and varied landscape for species to colonize and form communities.
The history of biodiversity also reveals that mass extinction events typically have long recovery periods, as well as restructure and reorder ecosystems and species composition in different and unexpected ways.
Key Takeaways for Master Naturalists
Why should a Master Naturalist, striving to earn volunteer hours, be concerned with changes in biodiversity over past millennia? Four reasons come to mind – the four C’s.
First, curiosity which is an essential ingredient of a Master Naturalist. We simply want to learn more about nature and the world around us, and a perennial question when we look around us is ‘how did this all come about?’.
Second, context. Part of being a Master Naturalist is observing, identifying, and noting patterns in the species and habitats around us. Knowing the history of the environment around us allows us to put what we are observing today into a larger context. Studying the long-run patterns and drivers of biodiversity provides a history lesson in species interactions, ecological feedbacks, environmental pressures, and evolutionary processes that shape today’s patterns of life. In the words of Michael Crichton, “If you don’t know history, then you don’t know anything. You are a leaf that doesn’t know it is part of a tree.”
Third, cause and effect. Understanding the cause -- how biodiversity emerged through processes such as evolution, extinction, and dispersal -- helps us to understand the effect -- current patterns, ongoing trends, and future likelihoods. So, ask yourself:
Finally, contribution. Understanding the trends and drivers of long-term biodiversity patterns provides a foundation and motivation for our various contributions as Master Naturalists in the areas of conservation, restoration, and stewardship activities, as well as our citizen science efforts. It provides the “bigger picture” that allows us to see how our efforts fit into something larger than ourselves and our immediate times.
In the next installment (Part 3), we will discuss the current and future state of biodiversity and some critical, and worrisome, trends unfolding around us.
 The processes of evolution, dispersal, and extinction are not entirely deterministic, but rather subject to historical contingency, so chance plays a role in the biodiversity we see around us. Historical processes, such as evolution, display some degree of “contingency,” meaning their outcomes are sensitive to seemingly inconsequential events that can fundamentally change the future. Contingency is what makes historical outcomes unpredictable. For example, “evolutionary outcomes may depend on idiosyncratic events that an evolving lineage experiences— such as the order of appearance of random mutations or rare environmental perturbations— making evolutionary outcomes unrepeatable” (Blount, Lenski, and Losos, 2018).
The Sixth Extinction, by Elizabeth Kolbert (2014, Picador Publishing)
Wonderful Life: The Burgess Shale and the Nature of History, by Stephen Jay Gould (1989, Norton)
Evolution: The Triumph of an Idea, by Carl Zimmer (2006, Harper Collins)
Barnosky, et al. (2011). Has the Earth’s sixth mass extinction already arrived? Nature 471 doi:10.1038/nature09678
Blount, Z.D., Lenski, R.E., and Losos, J.B. (2018). Contingency and determinism in evolution: Replaying life’s tape, Science 362: 655.
Erwin, Douglas H. (2000). Lessons from the Past: Biotic Recoveries from Mass Extinctions. Santa Fe Institute Working Paper: 2000-12-067
Locey and Lennon (2016). Scaling laws predict global microbial diversity. PNAS, 113(21): 5970–5975 www.pnas.org/cgi/doi/10.1073/pnas.1521291113
McMahon, S. and John Parnell (2018). The deep history of Earth’s biomass. Journal of the Geological Society, 175: 716-720, https://doi.org/10.1144/jgs2018-061
Mora, C.; et al. (2011). "How Many Species Are There on Earth and in the Ocean?". PLOS Biology. 9 (8): e1001127. doi:10.1371/journal.pbio.1001127
Pimm, S.L., et al., (2014). The biodiversity of species and their rates of extinction, distribution, and protection. Science 344 (6187), 1246752. DOI: 10.1126/science.1246752.
Looking out your window on a sunny day you’ll notice the different shrubs, trees, birds, and possibly a rabbit in your yard. And when you go for that hike in the park, there will be untold insects, maybe a frog, snake, or salamander. And of course, you can’t forget the wonderful morning smell of the skunk that passed through last night, or the deer quietly grazing in a neighbor’s meadow.
What you just experienced in a small way is the variety of life inhabiting the Earth – the biological diversity, or biodiversity, of nature. Biodiversity underlies everything we do as Master Naturalists.
At our last members meeting, Amy Johnson, the Director of Virginia Working Landscapes, discussed various biodiversity studies her group is involved with, pointing out some of the ways that scientists (and citizen scientists such as Master Naturalists) study biodiversity and its implications.
Scientists, however, have long debated how to precisely define and measure biodiversity. Is it the number of species? Is it the number different functional roles being fulfilled by various species in an ecosystem? Is it the genetic diversity in a population? Is it the diversity of ecosystems and how species come together in different assemblies?
The table below shows some of the many elements and dimensions that scientists consider when studying and measuring biodiversity:
The figure below shows another way of looking at biodiversity. Notice the three “standard” ways that scientists typically look at biodiversity – genetic diversity, species diversity, and ecosystem diversity – and some of the alternative ways – compositional diversity, structural diversity, and functional diversity.
Source: P. Duelli, M.K. Obrist / Agriculture, Ecosystems and Environment 98 (2003) 87–98
By now you’re getting the sense that biodiversity is much more than the “variety of life.” In some respects, trying to define it is akin to the parable of the blind men and an elephant. In other respects, it depends on what you are studying – local habitats, food webs, a particular species, or a larger landscape or region. For example, a study of a local habitat or niche may focus on biodiversity as the number of different species in that habitat or the genetic variation of the resident populations.
If the scale of the study is larger, say a watershed, landscape, or larger geographic region, the focus may be on the diversity of community assemblies or ecosystems present. Studies of food webs likely will focus on the diversity of functions different species perform.
These different perspectives on biodiversity (species, functions, communities) are also not independent of each other, but interrelated.
A formal definition that attempts to encompass these various dimensions of biodiversity is the 1992 Convention on Biological Diversity, an international agreement among 150 nations, which defined biodiversity as:
“…the variability among living organisms from all sources including, [among other things], terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species, and of ecosystems.”
This definition recognizes biodiversity as including genetic diversity, species diversity, and ecosystem diversity, among other dimensions and elements.
How is Biodiversity Measured?
It will come as no surprise that given the complexity of the biodiversity as a concept that there is not a single measure for biodiversity. Most biodiversity measures have two basic components – some measure of the number of entities present and some measure the degree of difference between those entities. For example, biodiversity can be measured by the number of species in a specific area, using such metrics as species richness (how many distinct species in an environment), or metrics such as evenness (how close in numbers each species in an environment is), rank abundance (relative species abundance), and various other species diversity indices, such as the Simpson Index or Shannon Index, that capture the degree of difference between species in a sample. Endemism richness is another type of biodiversity measurement that focuses on the proportion of rare, locally occurring endemic species. The field of biodiversity measurement is a subject that can cover several graduate courses in ecology.
To illustrate the problem of measuring biodiversity, look at the illustration below - which of the two areas below do you consider to have a higher biodiversity?
The two areas have the same number of individuals (20). The area on the right has more species (8) (species richness), but the ecosystem on the left has greater evenness across species as reflected in a higher Shannon Index. The Shannon Index quantifies the uncertainty in predicting the species identity of a random individual (i.e., the less difference there is among species, the greater evenness). As the Shannon index approaches zero, species differences approach zero (monoculture), hence a larger Shannon Index number is indicative of greater the biodiversity. The two areas might also be compared based on endemic richness. For example, if the ant, beetle, and frog in the right ecosystem were endemic species to that particular local area, then the ecosystem on the right might be considered more biodiverse and worthy of conservation.
Biodiversity also might be measured by the variety and number of different functions that species fulfill in an ecosystem, such as primary producers, herbivores, and carnivores. Functional diversity can be measured in a number of ways (Laureto, et al., 2015; Song, et al., 2014). One way is by the complexity and connectivity of a food web and the functional roles in the food web. In Figure 2, functional diversity on the right side would likely be different from the left side (e.g., the right-side area, populated by frogs, beetles, and ants in a pine forest would likely produce different functions and food web structure than the left-side area dominated by crows and salamanders).
Apart from species and functions, biodiversity might also be characterized by the degree of ecosystem diversity. Ecosystem diversity is the largest scale of biodiversity measurement, and within each ecosystem, there is a great deal of both species and genetic diversity. In Figure 2, one could study biodiversity by comparing the differences in communities and species assemblies between the left and right side “ecosystems”.
An example of ecosystem diversity is the Southern Appalachian region—stretching from West Virginia and southwestern Virginia to northern Alabama. This region has a number of diverse ecosystems which contributes to the area’s high biodiversity.
Fun Fact: Virginia has over 3800 species, including the third-highest number of amphibian species, and the 13th highest number of vascular plant species in the United States.
Within this region, Virginia has a variety of physiographic areas—from western mountains and valleys, to rolling hills, to Tidewater estuaries— that provide many habitats supporting a wide variety of ecosystems. For example, the Clinch Mountain Wildlife Management Area—covering about 25,000 acres in Russell, Smyth, Tazewell, and Washington counties—is considered to be Virginia’s “most biologically diverse [management area], due in large part to the vast differences in elevation on the area” and is particularly known for the diversity of fish and mussels in the area’s watersheds. On the other side of the state, the aquatic ecosystems and wetlands of the Chesapeake Bay and Virginia’s southern coastal environments are sites of significant biodiversity.
Master Naturalists and Biodiversity
As a Master Naturalist, you are involved with biodiversity at every turn. Stream monitoring and water quality assessments are based on sampling the macro-invertebrate species richness found in a particular reach of a stream. Butterfly surveys record the number and differences in species found in a local area. Volunteer work on native plants, pollinator gardens, and habitat restoration is fundamentally aimed at supporting greater biodiversity. Feeder Watch and the Great Backyard Bird Count help assess the diversity of local bird populations. And that ubiquitous invasive plant removal projects, and more recently our work with Spotted Lanternfly monitoring, are aimed at threats to biodiversity. I am hard pressed to think of any project we undertake as Master Naturalists that is not tied either directly or indirectly to biodiversity.
There are a number of resources you can use for further insights about biodiversity – some our listed below in further reading and references. Also, on the ORMN website there are blogs, science research, news articles and other resources on various aspects of biodiversity.
In the next installment of this series, we’ll travel back in time a few hundred million years to see how biodiversity has waxed and waned over the millennia. Until then, get out and enjoy the variety of life around you!
The Diversity of Life, by Edward O. Wilson (1992, Harvard University Press)
The Invention of Nature: Alexander Von Humboldt’s New World, by Andrea Wulf (2016, Knopf)
Evolution: The Triumph of an Idea, by Carl Zimmer (2006, Harper Collins)
Duelli, P. and M. Obrist, (2003). Biodiversity indicators: the choice of values and measures, Agriculture, Ecosystems and Environment, 98: 87-98.
Gaston, K.J. and Spicer, J.I. (2004). Biodiversity: An Introduction, Blackwell Publishing, 2nd Edition
Laureto et al., (2015). Functional diversity: an overview of its history and applicability, Natureza & Conservação, 13(2): 112-116, doi.org/10.1016/j.ncon.2015.11.001.
Ecosystems and Human Well-Being: Biodiversity Synthesis, by The Millennium Ecosystem Assessment (2005, World Resources Institute)
Mora, C.; et al. (2011). "How Many Species Are There on Earth and in the Ocean?". PLOS Biology. 9 (8): e1001127. doi:10.1371/journal.pbio.1001127.
Song et al, (2014). Relationships between functional diversity and ecosystem functioning: A review. Acta Ecologica Sinica. 34: 85–91. Doi: 10.1016/j.chnaes.2014.01.001.
Tilman, David (2012). Biodiversity and Environmental Sustainability amid Human Domination of Global Ecosystems, Daedalus, 141(3): 108-120, Summer 2012.
 The parable is a story of a group of blind men who have never come across an elephant before and who learn and conceptualize what the elephant is like by touching it. Each blind man feels a different part of the elephant's body, but only one part, such as the side or the tusk. They then describe the elephant based on their limited experience and their descriptions of the elephant are different from each other.
SERC: Landscaping for Biodiversity: A plant-insect perspective
Also, please find additional resources provided by Dr. Burghardt:
The variety of life on the Earth is an enduring source of wonderment and mystery. Whether you are bird watching in your backyard, counting invertebrates to assess stream quality, planting oak trees and native plants in your local park, or hiking through Shenandoah National Park, the diversity of life is all around you. Its why you look out your window in the morning and stock the bird feeder in the winter.
Biodiversity is at the core of everything we do as Master Naturalists. Whether it’s citizen science projects, stewardship, or education outreach, a Master Naturalist must understand the patterns of nature -- the interconnected relationships between plants, birds, trees, insects, mammals and their environment. Without biodiversity, there would be no patterns or relationships in nature to observe. There would be no nature.
So how did biodiversity arise, what is biodiversity, and how is it changing over time? In this six-part series, I will explore each month the many facets of biodiversity, what it means for us, and how we can sustain it. The series will cover the following topics:
So put on your wonderment goggles (free with three box tops and a self-addressed stamped envelope) and come along for the ride…..
What is an invasive species? An invasive species is "an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health" - click here for more
Spotlight on a local invasive species: Garlic Mustard - click here
The cost of invasives, read this article - click here
Look up invasive species and lots more at this cool website - click here
Trilliums, bloodroot, violets - many wildflowers of spring in eastern North America bloom thanks to ants. The tiny six-legged gardeners have partnered with those plants as well as about 11,000 others to disperse their seeds. The plants, in turn, "pay" for the service by attaching a calorie-laden appendage to each seed, much like fleshy fruits reward birds and mammals that discard seeds or poop them out. But there's more to the ant-seed relationship than that exchange, researchers reported last week at the annual meeting of the Ecological Society of America, which was held online. Read More Here.
By Charlotte Hartley
Aug. 6, 2020 , 11:00 AM
With their dazzling metallic hue, the blue fruits of the laurustinus shrub (Viburnum tinus), a flowering plant popular in gardens across Europe, are a sight to behold. But it’s what lies beneath the surface that’s caught the attention of scientists in a new study.
Researchers viewed samples of the fruit tissue through an electron microscope to examine their internal structure. They found no blue pigment as is typical in other blue fruits such as blueberries—just layers and layers of blobs. These blobs turned out to be tiny droplets of fat, arranged in a manner that reflects blue light—a phenomenon known as “structural color”—the team reports today in Current Biology.
Below the fat droplets lies another layer of dark red pigment, which absorbs any other wavelengths of light and intensifies the blue shade. The team verified these findings using computer simulations, confirming that this type of structure can indeed produce the precise shade of blue seen in the laurustinus.
The striking color of laurustinus fruits may signify its high fat content to birds. Although structural color is well-documented in animals, including in vibrant peacock feathers and delicate butterfly wings, it is rarely observed in plants. What’s more, this is the first time that fats have been found responsible for this mechanism. The team suspects it may be more widespread, and hopes to identify this type of structure in other species.
Bird of the Yellow Mask
REC Cooperative Living
The distinctive hooded warbler sings its song through the East and South. Read about it HERE.
By drilling into lake bottoms, researchers collect mud cores with fossil pollen that reveal the history of plants.
By Elizabeth Pennisi
Aug. 5, 2020 , 12:00 PM
Recent human activity, including agriculture, has had a greater impact on North America’s plants and animals than even the glaciers that retreated more than 10,000 years ago. Those findings, presented this week at the virtual annual meeting of the Ecological Society of America, reveal that more North American forests and grasslands have abruptly disappeared in the past 250 years than in the previous 14,000 years, likely as a result of human activity. The authors say the new work, based on hundreds of fossilized pollen samples, supports the establishment of a new epoch in geological history known as the Anthropocene, with a start date in the past 250 years.
“It’s hard to overemphasize how profound the effects of ending a glacial cycle are,” says Zak Ratajczak, an ecologist at Kansas State University, Manhattan, who was not involved with the work. “So for humans to have that kind of impact is pretty amazing.”
For more than 10 years, researchers have debated when humans started to make their mark on the planet. Some argue agriculture transformed landscapes thousands of years ago, disrupting previously stable interactions between plants and animals. Others argue the launch of large-scale mining and smelting operations—seen in glacial records going back thousands of years—means the Anthropocene predates the industrial revolution. For geologists, however, the epoch starts with a different signal: nuclear explosions and a sharp uptick in fossil fuel use in the mid–20th century.
But some skeptics suggest the ice ages have had an even greater effect on the world’s ecosystems. To test that idea, Stanford University paleoecologist M. Allison Stegner turned to Neotoma, a decade-old fossil database that combines records from thousands of sites around the world. Her question: When—and how abruptly—did ecosystems change in North America over the past 14,000 years? Climate-altering glaciers, which started their retreat roughly 20,000 years ago, pulsed back during a cold period called the Younger Dryas, from about 12,800 until 11,700 years ago. After that, North America abruptly warmed, marking the beginning of our current epoch, the Holocene.
To answer her question, Stegner and colleagues looked at how vegetation shifted in locations across North America, using fossilized pollen to determine which species of plants were present at any given time. From 1900 records of mud cores drilled from lake bottom, Stegner found 400 with enough fossil pollen—and accurate enough dating—to analyze.
She and her colleagues then tracked how the mix of pollen in each core changed over time, paying close attention to abrupt shifts. Such shifts can mark the transformation of an entire ecosystem, for example, when a grassland becomes a forest or when a spruce forest changes into an oak forest. Looking at 250-year intervals, the researchers ran two types of statistical analyses that separately picked out temporary and long-term disruptions. “Allison used some very creative and rigorous methods,” says Jennifer McGuire, a paleoecologist at the Georgia Institute of Technology who was not involved with the work.
When the last ice age ended, forests and grasslands regrew across North America, creating a landscape that remained stable for thousands of years. But humans have changed all that, Stegner reports this week. Her team found just 10 abrupt changes per 250 years for every 100 sites from 11,000 years ago to about 1700 C.E. But that number doubled, to 20 abrupt changes per 100 sites, in the 250-year interval between 1700 and 1950. When the ice sheets of the Younger Dryas retreated, starting about 12,000 years ago, that number was 15. This suggests, Stegner says, that human activity starting 250 years ago—from land use change to pollution and perhaps even climate change—had more of an impact on ecosystems than the last glaciers.
The researchers also analyzed whether some regions have changed more swiftly than others. Over the past 250 years the U.S. Midwest, Southwest, and Southeast have undergone massive shifts from forest, grassland, and desert ecosystems to agriculture and tree plantations, she says. In contrast, Alaska, northern Canada, and parts of the Pacific Northwest underwent more changes as the glaciers melted than in the past 250 years.
“We already know plenty about climate change,” says Kai Zhu, an ecologist at the University of California, Santa Cruz. “This study adds land use change, [which] might accelerate climate change in altering plants at a continental scale.”
That’s worrisome, McGuire adds, because plants are the foundation of an ecosystem. “This rapid turnover is a harbinger of the extinction risk and the overall ecosystem disruption that is impending,” she says. At another meeting session, she and student Yue Wang reported “very similar trends” after using pollen to examine how forests, tundra, deserts, and other biomes have bounced back from disruptions through time. Combined, the new work “eliminates any doubt” that humans have set off a new geologic epoch, Stegner says.
Tis the Season for Turtles: Maryland turtles are out and about in summer's warm weather.
Published July 28, 2020 in Conservation
A turtle isn't Maryland's state reptile for nothing.
Eighteen turtle species can be found throughout the state and in state waters—in ponds and bogs, streams and rivers, woodlands and wetlands—from the mountains of Garrett County to the waters of Worcester County and everywhere in between.
With so many turtles making their way (slowly) around, it's not uncommon for Marylanders to encounter them in the wild, particularly in summer when the weather is warm. If you see one, what should you do?
The general rule—as with all wildlife—is to keep a respectful distance and look but don't touch. You can disrupt a turtle's activity by touching or moving it. For example, aquatic species encountered on land are most likely females looking for a suitable spot to dig a nest and lay eggs. Females strive to find the perfect location where predators can't find their eggs and where their hatchlings can find their way back to water. Handling them during this vulnerable time would be very disruptive.
Eastern Box Turtle
With their dark shells covered in yellow-orange spots, Eastern box turtles are one of the most encountered species in Maryland, often found while hiking through forests. Unfortunately, many box turtle populations are now in decline due to habitat loss from development and road mortalities.
This woodland species is terrestrial, spending most of their time on land, in sunny open spaces as well as shady hiding places. They have a strong homing sense and are known to live out their lives in an area about the size of a football field, which is why they should never be picked up and moved.
An exception is if you find a box turtle in a place where it's not safe, like trying to cross a road. Each year, countless turtles are killed by cars. Among the tips the Mid-Atlantic Turtle and Tortoise Society offers for helping a turtle cross a road is to move it the shortest distance possible in the same direction it was heading, at least 30 feet from the road. Follow MATTS' recommendations for safely handling turtles, using two hands to hold both sides of the shell and lifting gently. A thorny briar patch or carpet of fallen leaves gives the turtle places to hide from predators.
From March to September, these turtles with bright red stripes on the side of their heads can be spied swimming and basking in the Inner Harbor, Lake Montebello and Lake Roland, among other spots in Baltimore City and most Maryland counties. They prefer freshwater habitats but can tolerate low-salinity, brackish water, and favor the still water of ponds, lakes, reservoirs and slow moving sections of rivers to fast moving streams.
These turtles are an invasive species, native to the mid- and south-central United States. Thanks to the pet trade, the red-eared slider is now the world's most widespread freshwater turtle. Hatchlings the size of a quarter can grow bigger than a dinner plate and live for 30 years, so irresponsible pet owners choose to release the turtles rather than continue to care for them. Red-eared sliders with shells bigger than 4 inches can still be sold in Maryland pet shops, but it's illegal to sell hatchlings. If you see red-eared slider turtle hatchlings for sale in Maryland, it's best to report it to the Natural Resources Police at 410-356-7060. And if you have a pet turtle of any kind that you can no longer keep, do the right thing; don't release it into the wild.
A close relative of the red-eared slider, the yellow-bellied slider, is now being observed with increased frequency around Maryland. Yellow-bellied sliders are native to the southeastern U.S. and, like the red-eared slider, are most likely now being seen in Maryland because people have released unwanted pets into the wild.
Snapping turtles are another common species found throughout Maryland, in or very near fresh or slightly brackish water. They can grow quite large—with a shell length ranging from 8 to 14 inches—and their bites pack a punch. Because their necks are long and flexible enough for their powerful jaws to reach most parts of their body, it's not a good idea to touch one or pick it up.
Female snapping turtles sometimes lay their eggs a fair distance from the water they emerged from, so you can sometimes find hatchlings far from water, trying to make their way to it. It's important to leave the hatchling outdoors, but if you feel it's in danger, you can carefully move it closer to the water's edge where there is plenty of mud and places to take cover.
The diamondback terrapin is Maryland's official state reptile and has been affiliated with the University of Maryland College Park since 1933. Terps officially became the school's mascot in 1994. To protect diamondback terrapins in Maryland, a 2007 state law (which the National Aquarium helped pass) bans removing them from the wild for commercial purposes.
Young terrapins are vulnerable to predators on land, in water and from the sky, including birds, raccoons, opossums and foxes. They prefer brackish water and spend their early years hiding in marsh grass habitat that gets flooded by high tides twice a day. If you find a terrapin out of habitat, it's best to release it in the nearest marsh grass habitat during a high tide.
Share What You See
If you happen to see a turtle or other reptile in the wild, whether during the City Nature Challenge or not, consider uploading a photo and information to iNaturalist to share your find with others!
by Delia O'Hara
Autumn-Lynn Harrison, Program Manager of the Migratory Connectivity Project (MCP) at the Smithsonian Migratory Bird Center at the National Zoo, learned to love animal migrations as an undergraduate student at Virginia Tech, watching wildebeest pound across the Serengeti in Africa in their annual search for greener grass. Now, Harrison coordinates the MCP's ambitious efforts to discover a fuller picture of the lives of birds: Where do birds like the long-billed curlew or the broad-winged hawk, spend their winters? Where do birds we see in other seasons go to breed?
These questions are of an urgent nature as bird populations are facing steady declines around the world. Last fall, an alarming study showed that North America has lost three billion birds since 1970, about one-third of the total bird population. For Harrison, however, the study created new resolve around learning all we can about birds in hopes of saving them.
“Without that knowledge of where they go, we can't even begin to figure out where the impacts are” — or how to structure conservation efforts, says Harrison, an ecologist and conservation biologist.
The question of why some birds disappear for several months has intrigued humans for millennia. Europeans theorized that birds hibernated in rivers to survive winters, like frogs; or turned into other birds; or flew to the moon. Then, in 1822, a hunter shot a stork in northern Germany and discovered an African arrow embedded in its body. But the mysteries of the 40% of bird species that migrate are only now beginning to be unraveled. Electronic tracking, such as small devices that are attached to birds, and other technologies, have played a large role in this, Harrison says.
Early trackers used in the 1990s were so big that only large birds like albatross and eagles could fly with them, she says. Now, tiny GPS devices with solar-powered batteries are being fitted to much smaller birds.
The MCP has field projects all over the Americas to track migrating birds, working with graduate students and agency biologists, choosing species that little is known about, or that have markedly declining numbers — the common nighthawk, rusty blackbird and Connecticut warbler, to name a few. Harrison herself leads projects involving oceanic and coastal birds, often in Arctic North America, a natural fit for a biologist with a background in marine animals. One bird Harrison studies, the Arctic tern, travels from the northern tip of the world every year, to the southern tip, and back, which can be an annual journey of more than 44,000 miles, Harrison says.
Earlier in her career, Harrison studied the migrations of large oceanic predators like seals, sharks and leatherback turtles as part of the Tagging of Pelagic Predators project. In one study of 14 such species, her team looked at their relationship with the human societies they pass, and the various levels of protection they are afforded as they travel. She presented that study’s findings to participants of the United Nations First Intergovernmental Conference on Sustainable Use of Marine Biodiversity Beyond National Jurisdiction, in hopes of bolstering the chances of a treaty, still under consideration, to make migrating sea animals' journeys safer.
Harrison travels extensively for her research, and she will go back to that once the pandemic eases. This summer, though, there is a moratorium on travel.
So instead, “We have been able to take a breather, revisit the data we have collected, and tell some of the interesting stories,” she says.
One such story includes the first full-year tracking, held through 2019-2020, of the Pomarine Jaeger, a “gnarly” predatory seabird that breeds in the Arctic.
“We discovered that three closely related species of Jaegers nesting on the same island in the Arctic dispersed during migration to four different oceans to spend the rest of their year,” she says. “That's amazing to me.”
Harrison has also enjoyed returning to live near the Chesapeake Bay to work at the Smithsonian. She grew up on the bay, on the Eastern Shore of Maryland, where her father's family settled in the 17th century and became “watermen”— solely oystermen until the collapse of the oyster population forced them to diversify into harvesting eels, crabs and other food animals in the bay. Harrison's parents were a math teacher and office manager of an electrical contracting company, but she spent time at her grandmother's house on Tilghman Island, “poking around in the marsh.” She knew early on she would be a biologist, but thought she would be an estuarine researcher, studying Chesapeake Bay.
And lately, Harrison has indeed had a chance to study brown pelicans in the bay with Dave Brinker of the Maryland Department of Natural Resources, who discovered their first nest found in Maryland, in 1987. Harrison's father came with her as a field volunteer on one trip, and it was “very special to have him involved,” she says.
“I respect scientific knowledge so much,” she says. “But I got a different kind of education from people who got up at 4 am to go out to catch crabs. They know the bay, they know the animals, they know these systems. That's knowledge to respect, too.”
by Marsha Walton
Herpetologist and University of Arizona Ph.D. candidate Earyn McGee’s research has her well prepared for obstacles like oppressive heat, treacherous terrain and even venomous animals. Her field research takes her to the Chiricahua Mountains of southern Arizona, where she’s determining the effects of stream drying on lizard communities for her doctorate research in conservation biology. This enables McGee a closeup look in studying lizards and their diet, and how the climate crisis may be altering it. She and the undergraduates she works with must first deftly catch the reptiles, weigh and measure them, then document their sex and overall health.
It is demanding and unpredictable work. And it has sometimes been made riskier by unsettling encounters with police, whose actions imply that, as a young scientist of color, she does not have a right to conduct her field studies.
“Where I work is pretty remote,” says McGee. “A lot of the time, it's Border Patrol, or some form of law enforcement stopping us [from working]. Last year, we had these military guys follow us into our site. A couple of days prior, we were out in the group with a whole lot of white people, we didn't have that same type of surveillance in the same exact spot,” says
Already well known as a science communicator on social media, McGee counters such racist incidents with the message that the natural world belongs to everyone to love and to protect. And she stresses that excitement for nature can come at any point in time, whether hiking through a National Park or looking up at a tree in New York City. Her courage in speaking out went viral shortly after a white woman made racist threats against Black birdwatcher Christian Cooper in Central Park on May 25, 2020. McGee and several colleagues, who had already been communicating about academic and diversity issues, sprang into action. They created #BlackBirdersWeek.
Photos and experiences soon flooded social media from all over the world. In interviews and podcasts during the week (May 31-June 5), scientists and naturalists shared examples of Black people, from birders to hikers to photographers, enjoying nature and outdoor spaces. The Central Park incident of racism, and the Twitter and Instagram responses to it, became another visible, widely shared facet in what’s become known as the U.S. Civil Rights racial injustice reckoning of 2020.
Besides her activism aimed at adults, McGee also shares her knowledge about wildlife conservation with a younger
audience. Lizards may be small, she says, but they can also be very swift and very clever. “[Catching] them the first time, depending on the lizard, can be relatively easy. But that next time when they see you coming, they're like, ‘Oh no, not this again,’ and they take off running,” she says.
And she has some stories of these types of experiences she often shares on her social media accounts. “So I'm running after this lizard, sprinting. This lizard is really putting up a good chase. I'm hopping over logs and rocks and stuff. I caught her, but before I did, I took a picture and I told people on Twitter the story of what happened,” says McGee.
Her followers were intrigued by the elusive lizard story. Since June 2018, thousands of curious students and adults regularly scour the photos on her informal Twitter quiz, using the hashtag, #FindThatLizard. After locating the reptiles, McGee then shares details about their camouflage, eating habits and survival skills. She’s heard from many science teachers who now start their classes off with this quest.
McGee says lizards are an easy sell to get kids hooked on science. In her outreach work, she shares fun facts about lizards, such as some lay eggs, some give live birth, others can even clone themselves. And what’s not to love about a Gila monster, asks McGee? “People pay money to come from all around the world for the hope of seeing this lizard (the Gila monster). It's one of few venomous lizards in the world, and compounds from its saliva have been used to create medical treatments for diabetes. So, lizards are cool,” she says.
McGee’s activism and fearlessness led to her recognition as one of the younger AAAS IF/THEN® Ambassadors. In her role as an ambassador, McGee shares with young girls her expertise on the power of social media for women and underserved minorities in STEM fields. She also hopes to introduce young girls to career paths in natural resources.
Still, McGee knows other types of outreach are needed to improve diversity and equity in STEM. While she says there is currently a lot of activism on her own campus to combat racism and xenophobia, McGee says institutions need to do more to assist Indigenous Mexican-American and undocumented students. When her studies are complete in about a year, McGee plans a career as a science communicator, perhaps hosting a nature show on TV. And her quest for social justice will stay closely tied to her career path. “I really want to be able to create pathways for Black, Indigenous, other people of color to enter into natural resources fields, and even if they don't want to do it as a job, maybe find it as a new hobby. So that's really what I hope to accomplish in the future,” said McGee.
By Meagan Cantwell
Jul. 27, 2020 , 9:00 AM
To save energy, many insects swivel their head—instead of their entire body—to scan the world around them. Researchers have now replicated this with a tiny camera with a one-of-a-kind arm they can maneuver from a smartphone. The total system weighs just 248 milligrams—less than a dollar bill.
When strapped onto a beetle’s back, the camera can stream video in close to real time. It can also pivot to provide a panoramic view from the beetle’s perspective (as seen in this video). What’s more, when the camera was mounted onto an insect-size robot, the bot used up to 84 times less energy by moving the arm of the camera instead of its entire body.
The technology is one of the smallest, self-powering vision systems to date, researchers report this month in Science Robotics. In the future, scientists could use these tiny cams to gain insight into the habits of insects outside the lab.
The fascinating features and critical role of these nocturnal pollinators
A freshly emerged cecropia moth dries its wings. A type of silk moth, the cecropia is the largest moth species in North America. (Photo by Mark Beckemeyer/Flickr CC BY-NC 2.0)
by Caitlyn Johnstone
July 21, 2020
Chesapeake Bay Program
submitted by Bonnie Beers
Human focus on nature tends to be what we can see and when we can see it during the day. We rightfully champion the busy worker bees, smell the roses and delight in birdsong, yet nature always has new surprises in store. In recent years we’ve begun to discover what happens sight unseen. Flowers fluoresce in brilliant hues beyond the capability of human eyes. Some plants increase the sugar content of their nectar when they detect the vibration of a bee’s wings. And contrary to our assumption that bees and butterflies are the primary players, a lot of pollination happens while we sleep—thanks to moths.
Moths as powerhouse pollinators
Moths are an evolutionary group that dates back way before the dawn of the bees and butterflies. Because we are more likely to see them during the day, humans are more familiar with butterflies than with moths. However, moths outnumber butterfly species nine to one in discovered Lepidoptera (the insect order that contains moths and butterflies). There are more than 11,000 species of moths in the U.S. alone, and they are a wealth of fascinating facts. In comparison to moths, researcher Jesse Barber of Boise University referred to butterflies as, “an uninteresting diurnal [daytime] group of moths.”
A recent study in England found moths are outshining other pollinators, fertilizing more types of plants and flowers that bees overlook. Many bees and butterflies preferentially target flowers rich in nectar. Moths, on the other hand, are generalists, frequenting a wider range of species and visiting those that bees skip. These night shift moths, it turns out, are crucial to pollination.
A rosy maple moth is seen in Howard County, Md., on June 12, 2020. (Photo by Emilio Concari/iNaturalist CC BY-NC)
Their pollination power is due in part to the tiny scales that give moths their fur-like covering. As the moths visit a diverse array of flowers and enjoy the nectar, their fuzzy bodies collect pollen like a feather duster.
While critical to the moths' role in pollination, their fluff actually evolved to confuse the sonar of night-feeding bats. In fact, the evolutionary arms race with bats has been playing out for a long time. Moths can hear, which researchers used to believe developed to help them escape bats and their sonar technology. However, it may be the other way around. Moths and their ears are older, evolutionarily speaking, so it may be that bats evolved their sonar to better capture moths that already have a leg up on detecting a predator’s approach.
Fascinating moth features: The proboscis (the tongue)
A snowberry clearwing, also known as the hummingbird moth or flying lobster, visits bull thistle growing along the Anacostia River on Kingman Island in Washington, D.C., on Aug. 15, 2019. (Photo by Will Parson/Chesapeake Bay Program)
Moths have an elongated appendage known as a proboscis that can adapt to extract nectar from many types of flowers.
These incredible tongues were even written about by Charles Darwin, who marveled at their design and suggested the moths with these proboscises might be the whole reason certain orchids existed. While he was scoffed at for this theory, researchers recently captured footage of a sphinx moth pollinating the beautiful and ethereal ghost orchid using its 30cm proboscis.
Moths are so adept with these tongues that they can even drink the tears of sleeping birds without waking them.
The antennae of a male luna moth, pictured, are wider than those of a female because it uses them to seek out the pheromones emitted by the female, which remains stationary until after mating. (Photo by Mike Keeling/Flickr CC BY-ND 2.0)
As fabulous as they may appear, the feather-looking antennae of some moths are far from decorative. The detailed structure actually helps the male detect female pheromones from up to several miles away, depending on the species. According to Dr Qike Wang in a recent study, the scales that form the antennae are angled to serve the dual purpose of enhancing female scent and diverting contaminants like dust. The special design creates an area of slow airflow around the antennae, helping the scent to linger and increasing the effectiveness of the pheromones around the sensilla (the sensory receptors).
For the lady moth’s part, she is smelling more than the male’s presence. A female moth has the ability to detect reproductive fitness in the male moth’s pheromones. Believe it or not, humans may also have this ability.
Showy emerald moths are drawn to artificial lights. Green in color as adults, the caterpillar form of this insect resembles a crumpled dead leaf. (Photo by Audrey Hoff/iNaturalist CC BY-NC-ND)
“Like a moth to a flame” may be a common phrase, but moths aren’t actually attracted to light itself. When we put lights on our porches and seem to entice moths to it, we’re interfering with the way they orient their world. Moths navigate by the light of the moon, so they keep it at a certain angle to their body. All of the artificial lights we have now are like millions of road signs sending moths in the wrong direction.
When they emerge from their cocoons, moths still look like pudgy piglets with fluff and tiny wings. A newly emerged moth will pump fluid, called hemolymph, into its wings to unfurl them to their full adult span. Using their antennae to help balance, strong muscles in their thorax then move the wings up and down and propel them off in search of mates and flowers.
Moths of the Chesapeake
From the mountains of West Virginia to the lakes of New York and the hills of southern Virginia, the Chesapeake watershed boasts a number of impressive moth species.
The most captivating of our region’s moths, at least color-wise, may be the rosy maple moth, Dryocampa rubicunda. This moth has large eyes and is delightfully fluffy, sporting a cotton-candy-lemonade coat of bubblegum pink and bright yellow. As the name suggests, rosy maples gravitate to maple trees.
Rosy maple moths are in the silk moth family, Saturniidae, which sports several stunning species that can reach close to the breadth of an adult human’s hand. Silk moths in the Chesapeake are numerous and include such members as the Polyphemus, whose caterpillar eats 86,000 times its body weight, and the woodland-dwelling Prometheus, whose light green caterpillar becomes a black to brown adult moth with a wingspan reaching close to four inches.
The spots giant leopard moth, Hypercompe scribonia, shine iridescent blue. (Photo by Greg Lasley/iNaturalist CC BY-NC)
The largest of the silk moths is the Cecropia, which begins its life as a shockingly adorned and bulbous four-inch caterpillar in shades of black to light green with a bluish hue. Once emerging from its cocoon, the cecropia moth unfurls wings of stunning white, orange and grey that reach almost six inches across. The body is equally beautiful, with a fuzzy red face and feet and body bands of crisp black and white. As the sole purpose of the short-lived adult is to mate and reproduce, cecropia do not have a digestive tract.
Lunas are one of the most recognizable of the silk moths, eliciting admiring sighs from humans lucky enough to spot their fleeting beauty. Lunas do not have a functioning mouth, living only a few days in their adult form. Their pale green, ethereal wings rightfully distract from the body, though this too is strangely beautiful with its creamy coloring and red wine-hued legs. They have long tails on the ends of their wings, which spin as the moth flies. The fluttering of the tails confuses the sonar of bats and affords these night-flying lovelies some additional protection while finding their mates.
Not all moths are nocturnal, and some don’t even look like what we think of as moths. One unusual moth in our watershed is the hummingbird moth, a massive insect many people have seen and mistaken for a bird while watching them visit common garden flowers such as bluebells, bee balm, phlox and verbena. Hummingbird moths like the snowberry clearwing are active during the day, have chunky bodies and even make a humming sound like a hummingbird. If you are interested in seeing these fascinating cross-overs of the animal world, look no further than the leaf piles outside. The loose cocoons of hummingbird moths are often found in leaf litter.
Some moth caterpillars in our region look terrifyingly poisonous but aren’t, like the hickory horned devil. Others look incredibly huggable but should not be touched, like the puss caterpillar. In their turquoise coloring and formidable spurs, the harmless hickory horned devil is one of the few moth caterpillars that does not spin a cocoon. Instead, it burrows into the ground to later emerge as the large and aptly named regal moth. On the opposite end of the spectrum, the fluffy exterior of the adorable puss caterpillar conceals venomous spines that can land a full grown human in the hospital with a single touch. Both cute and innocuous, the adult flannel moth appears to be sporting fluffy boots and is completely harmless. This is a southern moth, so it is found in our watershed only in the far-flung reaches of Virginia. Their cocoons are tough, and abandoned ones serve as ready-made homes for a variety of other insects.
The list of fascinating local moths goes on. Beautiful wood nymphs mimic bird poop, Scarlet Wings live on lichen, Clymenes are also called “goth moths” and vocalize back to bats. The world of moths is diverse and fascinating, and all moths mentioned can be found in our watershed. Stay up late some night and explore what is out there in the world of darkness.
About Caitlyn Johnstone - Caitlyn is the Outreach Coordinator at the Chesapeake Bay Program. She earned her Bachelor's in English and Behavioral Psychology at WVU Eberly Honors College, where she fed her interest in the relationship between human behavior and the natural world. Caitlyn continues that passion on her native Eastern Shore by seeking comprehensive strategies to human and environmental well-being.
Find out by reading this Scientific American article sent in by Bob Powers, Class X
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