Posted on December 20, 2016
Each week on the blog we pull back the curtain on our Wildlife Ecology & Conservation graduate students’ seminar class. This post is by Elan Simon Parsons.
If you look up and see a monkey in a tree, you might think you’re in the tropics—think Latin America, Africa, or Asia, where primates can dominate the treetops and the soundscapes. Or, according to research by Jane Anderson, you could just be in Florida.
Florida, with its major ports, subtropical climate, and tourist traffic, is vulnerable to biological invaders such as kudzu, Burmese pythons, and monkeys. Anderson, a 4th year PhD candidate in Interdisciplinary Ecology and Wildlife Ecology and Conservation at the University of Florida, wanted to study the effects of non-human primate populations that have, at various times, called the state home, and went to work collecting data for her dissertation.
To determine whether Florida’s monkey populations impact the area to the degree of other self-sustaining non-native species, Anderson first consulted the literature. While documentation recorded the presence of monkeys in the state, information was often spotty or difficult to confirm. After some digging, Anderson found historical evidence of three species of monkeys living outside of captivity in Florida: squirrel monkeys (Saimiri sp.), vervet monkeys (Chlorocebus sabaeus), and rhesus macaques (Macaca mulatta). Squirrel monkeys have had several short-lived populations across the state, and vervets in Florida consist of a small, stable population only in Broward county. Rhesus macaques, on the other hand, are a growing population in and around Silver Springs State Park, with indications of movement toward Ocala National Forest. Despite local legend, the macaques were not brought to the area for the filming of a Tarzan movie, but for a tourist attraction in the 1930s and 40s. Wildlife officials have culled the animals intermittently since 1984, though these attempts were usually met with organized protests.
Anderson’s first step was testing to confirm whether or not the rhesus macaques were predating on bird nests, as this species likely presented the greatest threat to populations of other animals. She constructed fake nests with quail eggs and additional clay eggs to identify predators by teeth marks, and found that in areas with macaques, nests survived longer than other areas even though the monkeys were also eating eggs. Why the nests survived longer is currently unknown, as are the overall effects of macaques on nest mortality in Silver Springs.
The next chapter in Anderson’s dissertation effectively mapped the home range of a group of macaques in Silver Springs State Park. Anderson tracked a troop of macaques north of the Silver River and found that they rarely crossed the river, spending most of their time in floodplain swamp, wetland areas that they might be affecting. The data, including information gathered from camera traps, suggested that humans feeding macaques may be altering their movements, keeping them close to the river on the weekends during periods of high human traffic.
Finally, Anderson evaluated different management scenarios—including culling and sterilization–over time with population simulations, because unhindered growth of the macaque population could wreak havoc on local ecosystems. Although her research does not advocate for any particular method, Anderson’s studies do provide natural resource managers with information they can use to make future management decisions about non-human primates. This is important because management techniques have historically been controversial, and public outcry can make management choices difficult. For example, around 300 individuals in Silver Springs were removed by the state in 1984, and another 700 removed between 1998 and 2012. Protests ensued, and the population grew again. But because of research like Anderson’s, we now have alternative measures to help keep populations in check. For instance, sterilization of 80% of adult females every five years or 50% every two years could effectively reduce the population and garner more public support.
Going forward, Anderson will further contribute our understanding of Floridian macaques by determining the prevalence of zoonotic disease spread to humans by monkeys in Silver Springs, and by establishing whether the source of other rhesus macaque occurrences in Florida are from the Silver Springs population.
So if you look up and see a macaque in Florida, it’s possible Jane Anderson isn’t far behind.
Posted on December 15, 2016
Each week on the blog we pull back the curtain on our Wildlife Ecology & Conservation graduate students’ seminar class. This post is by master’s student Elysia Webb.
How does the diversity of life emerge?
This question motivates Dr. Brunno Oliveira’s growing body of work on diversity. Life is incredibly diverse, and the variety in that diversity is remarkable. For instance, the diversity of life at the Antarctic pole is vastly different from that of the Amazon rainforest, or that in the deepest parts of the oceans.
But what mechanisms explain the spatial variation in the patterns of biodiversity? And where is biodiversity most likely to be lost? With advanced statistical modeling, Dr. Oliveira can examine these old questions through a new lens and make predictions about patterns of biodiversity loss. For while extinction can be a natural event, humans are accelerating extinctions by damaging conditions necessary for life. Understanding the factors that account for biodiversity differences can help researchers better predict the species and ecosystems most at risk.
Diversity is defined in several different ways. There is phylogenetic diversity, where a community made up of less-related individuals is more diverse. For example, an ecosystem with birds and mammals would be less diverse than an ecosystem with mammals, reptiles, and fish. A second way to define diversity is by function. For example, a community with seed, plant, and meat eaters is more diverse than a community of seed eaters.
There is an easily observable latitudinal gradient of species richness, with more species closer to the equator and less species as you move toward the poles. There are currently two competing hypotheses attempting to explain this pattern. The first states that biodiversity cannot increase without limits, and that it is dependent on, and constrained by, the environment. The second states that biodiversity increases without limits, and that it is unconstrained by ecological processes. Though each hypothesis has empirical data supporting it, Dr. Oliveira wanted to test each with data simulations and statistical modeling.
Dr. Oliveira used mammals as a model system, as they are widespread, species-rich, and have tremendous functional diversity of size, diet, and habitat. He examined mammals in terms of functional diversity and regional distribution, using 5000 “trees” to examine different possibilities to explain biodiversity. Of the three terms, which has the best correlation with evolutionary time and diversification rates?
The models found that functional diversity only follows latitudinal species richness in the Old World of Asia and Africa. This points to the likelihood that the functional diversity in the New World of South America is redundant. This means that South America has an excess of species from each functional type—more than necessary to maintain a healthy community. In an evolutionary timeframe, South America and Australia are the “oldest” communities. Both are notable for their diversity of Metatherians (marsupials), which are the most ancient mammalian clade. Diversification is slow in a majority of the world. The models reveal an interesting relationship between species richness and functional diversity: Older communities have more functional diversity than richness would predict, which also supports functional redundancy in species-rich regions, particularly South America. Functional diversity lags behind species richness, which is in turn negatively affected by diversification rate.
To summarize, “newer” communities have fewer species, and therefore diversify more quickly. Functional diversity takes longer than species diversity, so “older” communities have greater functional diversity. These are general trends, though different dynamics may prevail in different regions. The decoupled relationship between species richness and functional diversity suggests that richness is regulated by ecological processes, not niche diversity.
The Anthropocene period, or Age of Man, provides an immediately relevant context for these findings. In the 4.6 billion-year history of the earth, there have been five mass extinctions that wiped out the vast majority of species at Earth at the time. Evidence shows that the sixth has likely begun, and amphibians in particular are on the chopping block. Roughly 40% of amphibian species are in danger of extinction. Losing functionally-redundant species will have a smaller impact on the ecosystem than losing species that have unique functions. However, we do not know what extinction rates will be. Will the extinction rates of the future remove proportional amounts of phylogenetic and functional diversity, or will one be more impacted than the other?
Some basic tenets of mass extinction are commonsense. More species are expected to become extinct in areas where there are more species, such as around the equator. Dr. Oliveira’s model leads to unsettling predictions about the future, though. More phylogenetic diversity is expected to be lost in areas of higher biodiversity. Functional diversity will be lost the most in African tropics, Australia, and Southeast Asia. We will lose more functional diversity than phylogenetic diversity, except for in the South American Neotropics. And not all endangered species are created equal—each has differing amounts of unique evolutionary history and traits that would be lost if they went extinct. The most objectively “valuable” species to conservationists should be the ones that are most phylogenetically and functionally unique.
While measuring functional and phylogenetic diversity can help prioritize conservation efforts, it does not mean that the extinction of “redundant” or “less unique” species will not have negative effects on ecosystems. Further, Dr. Oliveira believes that there is an inherent value of existence that is worthy of protection, not just function.
To find out more about Dr. Oliveira’s research, please visit oliveirabrunno.wordpress.com.
So You Want to be a Conservation Biologist? Insights from a Life Dedicated to Tiger Conservation in India
Posted on December 9, 2016
Each week on the blog we pull back the curtain on our Wildlife Ecology & Conservation graduate students’ seminar class. This post is by PhD student Wesley Boone.
The Bengal tiger (Panthera tigris tigris) is arguably one of the most charismatic species in the world. Tigers have been popularized by pop culture (think Shere Khan, Tony the Tiger, and Tigger), are among the most common mascots in US college sports , and are adopted by numerous conservation campaigns. With so much positive publicity, it might be hard to believe that conserving tigers is an extremely complicated task. However, this challenge has been the focus of decades of research by Dr. Ullas Karanth.
Dr. Karanth did not begin his career with the aspiration of becoming a prominent conservation biologist. Instead, Dr. Karanth hoped to become an engineer, for which he attended college and received a Bachelors of Science in 1971. Following the completion of his degree, Dr. Karanth spent years working various jobs, including farming and selling farm equipment. After eight years of farming, Dr. Karanth met Dr. Mel Sunquist at a research conference in Bombay, India (present-day Mumbai, India). This meeting was professionally fruitful, as and the college educated engineer was soon at the University of Florida conducting ecological research. Dr. Karanth fondly remembers his conversion to ecology as being akin to “throwing a fish into water.” Dr. Karanth earned a master’s degree in Wildlife Ecology from the University of Florida in 1988, and a doctorate in Applied Zoology from Mangalore University in 1993.
Dr. Karanth’s research, while inclusive of many large mammal species, has focused on tiger conservation. In the years since he founded the Centre for Wildlife Sciences in 1984, Dr. Karanth has worked tirelessly to further his field of research. Each advancement, however, has been met with objection from national authorities. Dr. Karanth’s first issues arose when he collared four tigers and three leopards with tracking devices to study the animals’ movement. Following the incidental death of several collared tigers, authorities pulled his research permit believing he might in some way be connected to illegal tiger trading. Dr. Karanth took the issue to court, won the case, and restarted research. In return for his research efforts, Dr. Karanth was able to determine that tigers in Nagarahole National Park required15 km2 in range land per animal to survive. Siberian tigers, by comparison, may require upwards of 100 km2 each. This difference highlights the extreme productivity of the Nagarahole ecosystem.
Starting in 1991 Dr. Karanth pioneered a new method of estimating tiger abundance utilizing camera traps. Camera traps were uniformly placed in conservation areas known to have tiger populations. Then, individual tigers were identified in camera trap photos using their unique markings. This enabled Dr. Karanth to conduct a capture-recapture analysis, and thereby estimate abundance with a high degree of certainty.
Dr. Karanth presented the results to Indian politicians in hopes of expanding the scope of his camera trap study. Instead, those politicians believed traditional methods of estimating tiger abundance—utilizing unique identifiers within tiger tracks—were sufficient. To continue using his camera trapping methodology, Dr. Karanth was forced to obtain permission from a senior politician and equipment was purchased and monitoring began. However, before long his permits were rescinded and the ensuing litigation resulted in three years of lost data. Dr. Karanth persevered through all of this by remembering what was at stake: the continued existence of tigers in India. Although he faced many obstacles, he overcame each and was rewarded with resounding success.
Today, India has adopted some of Dr. Karanth’s tiger monitoring protocols, in part due to his continued lobbying and partially due to a scandal in which some parks were using plaster tiger paw casts to hide their dwindling population densities and/or extirpations, which would have prompted funding cuts for those parks reductions. However, application of his monitoring methods has been hindered by corruption, which has siphoned away funds intended for camera procurement and staff wages. Although India has not fully adopted his methods, other nations with tiger populations, including Thailand, have, and the persistence of tiger populations throughout southeast Asia is better because of it.
Dr. Karanth’s story is one of perseverance in face of blatant, misinformed, and unrelenting obstructionism. However, owing to Dr. Karanth’s grit, his is a success story showing how one person can change the face of conservation in both policy and practice. His path stands as an example of how conservationists across the globe may succeed regardless of political whims and so preserve the world’s natural resources for future generations.
Dr. Karanth has been a Senior Conservation Scientist for the Wildlife Conservation Society since 1988. He serves as adjunct faculty at the National Center for Biological Sciences in Bangalore, India and the Department of Wildlife Biology at the University of Minnesota, and supervises doctoral graduate students at Manipal University in Karnataka, India. Dr. Karanth has advised conservation efforts in Thailand, Malaysia, Cambodia, Myanmar, Indonesia, and Russia. Dr. Karanth has authored more than 75 peer reviewed scientific publications, and authored/edited four books. He has been awarded the Sierra Club’s International EarthCare award and World Wildlife Fund’s Sanctuary Lifetime Achievement Award. Dr. Karanth was inducted into the Indian Academy of Sciences in 2008.
Posted on November 30, 2016
Each week on the blog we pull back the curtain on our Wildlife Ecology & Conservation graduate students’ seminar class. This post is by master’s student Elysia Webb.
Dr. Lisa Davenport had a mystery on her hands: her birds kept disappearing.
During most of the year, the Orinoco geese and black skimmers happily nested and fed on the banks of the Amazonian rivers in Parque Nacional de Manu, Peru. But when the drenching rains of the wet season fell in November, they vanished. When the rains subsided in April and the rivers shrank, they reappeared just as suddenly. Especially mystifying was that the Orinoco goose, “the only true forest goose,” was classified as non-migratory. To figure out where the birds went, Dr. Davenport decided to track them.
Bird tracking techniques, which were developed to measure how avian diseases could affect humans, revealed bird “flyways,” or travel paths. While the flyways of Asia and North America are well-mapped, bird migration within the Amazon is poorly understood and researched. Though bird banding research is helpful in studying bird movement in the United States, it doesn’t work as well in the Amazon because the birds there are rarely recaptured by scientists, and bird bands are rarely returned by hunters who catch banded birds.
Understanding patterns of bird movement across the landscape is a pressing issue because of the threats facing the Amazon: Proposed mega-dams will alter the flow of water, petroleum leases will cause deforestation and pollution, and the channelization of waterways will change how water is distributed. For the wildlife that depend on the forest and its water, these changes will have significant impacts. Many fish and birds are important food resources for the people of the region, and they will be impacted as well if migration patterns shift.
Though the Amazon rainforest doesn’t have four seasons, there are important seasonal differences in water availability. North of the equator, the peak flow of water occurs in June and July. South of the equator, peak flow is in January and February. Because of these water differences, the rainforest is a diverse mosaic of habitats. The differences in water also appear to be the driving cause of migration for the black skimmer and Orinoco goose in Manu National Park.
Until recently, the question of “where do the birds go?” was impossible to answer. Now, with advances in technology, wildlife tracking is much easier than it once was. Telemetry units have become smaller and more efficient, so birds are no longer too small to be tracked (some units are so lightweight that they can be applied to dragonflies and beetles). Battery life used to severely limit data collection on long-distance migration, but recent advancements in solar-powered transmitters makes years-long tracking possible.
Using these improved technologies, Dr. Davenport was able to capture geese and skimmers at her field site and outfit them with lightweight transmitters. The transmitters communicate with orbiting satellites, and send regular progress reports back to the researcher. “It’s like the birds are sending letters home,” says Dr. Davenport. The emailed data is highly accessible, and can even be checked from a cell phone.
The “letters home” from the Orinoco geese showed some surprising patterns. This supposed non-migratory bird was clearly migratory, with many individuals flying from Peru to Bolivia during Peru’s wet season. The transmitters showed that the geese migrate at night, possibly to avoid predators such as hawks and eagles, or to take advantage of cool, nighttime air. Two of the birds tagged were a breeding pair and the data showed that they made the journey to Bolivia together, suggesting that mates may stick together longer than the breeding season. The skimmers, on the other hand, showed a much greater contrast. Some skimmers took the same paths as the Orinoco geese, and even ended up in the same park in Bolivia. Others flew over the Andes Mountains in the highest passes to access the Pacific coast. That the skimmers could fly so high was astonishing, and such a migration was thought nearly impossible.
Dr. Davenport’s research is ongoing, but the data is already changing the way we view bird migration in the tropics. Some sites, such as the park in Bolivia, might be disproportionately important to migratory birds. If these crucial stopovers are disturbed, it could be fatal to thousands of birds. Conservation funding should prioritize such sites.
Some patterns of avian migration might even apply to the neo-tropical area of southern Florida, where birds might move to take advantage of seasonal resources. As the human population of the tropics and neo-tropics continues to grow rapidly, migratory birds will suffer the consequences. Understanding their flyways and stopovers will help mitigate human-wildlife conflicts of interest, and preserve these species for generations to come.
Posted on November 23, 2016
Each week on the blog we pull back the curtain on our Wildlife Ecology & Conservation graduate students’ seminar class. This post is by master’s student Nick Vitale.
In response to the looming threat of climate change, Dr. Stephen Mulkey has undertaken an ambitious plan to redefine the college classroom. He stresses the need for learning environments to help “build society’s capacity for environmental mitigation, adaptation and resilience.” Though he has been accused of sounding like Dr. Doom, Dr. Mulkey believes that “avoiding catastrophic climate change will be the organizing principle for humanity for the next 30 years.” Institutions of higher learning, says Dr. Mulkey, have an ethical duty to prepare future generations for the challenges of climate change. In doing so, higher education can be a solution for fostering regenerative ecology and sustainability.
Climate change research has produced alarming evidence demonstrating why this type of education is critical. CO2 is increasing at unprecedented rates, and even if all emissions ceased today, CO2 levels would remain well above those of the pre-industrial era for hundreds of years to come.
Dr. Mulkey says that climate change matters because of its impacts on all living systems, and that it is already producing dramatic effects. For one, water currents in the Atlantic Ocean are slowing, which is widely suspected to come from the massive amounts of Greenland’s melting ice. Some of the environmental responses to climate change (such as decreases in permafrost) create their own negative cycles, further driving the forces controlling climate change.
Here in the U.S. our natural areas are predicted to experience catastrophic responses to climate change. The U.S. consists of a patchwork of disconnected natural lands. This fragmentation in the eastern U.S. may stop the environment from adapting to climate change because organisms are limited in their movement to new habitats. McGuire et al. suggest that recent efforts to create habitat corridors may not matter.
Dutton et. al suggest that with climate change, homogenization of forest types will occur by 2100, allowing a few resilient species to dominate the landscape while many others die off due to a changing environment.
Dr. Mulkey is an environmental scientist, and has spent more than 20 years as a forest ecologist. There he observed the effects of climate change on the landscape first hand. Later, Dr. Mulkey served as President of Unity College in Unity, Maine from 2011 to 2015. There, Dr. Mulkey started to implement his forward-thinking vision by initiating a movement among colleges to divest endowment from fossil fuel. He also restructured the classroom by integrating various disciplines and empowering students through problem solving.
Together with a team, Dr. Mulkey created a guide for college programs to adapt classes to meet the environmental imperatives that he feels are non-negotiable. Below are the major recommendations they suggest:
- Fully integrated IES (interdisciplinary environmental and sustainability) programs should have authority over staffing and resources and recognized status as an autonomous unit within the university.
- IES units should have their own core faculty lines in sufficient numbers and ranks to ensure effectiveness to meet their mission. Continuity of faculty is necessary for program stability, so tenure track positions are required.
- University budgets should explicitly allocate base funding for these programs in sufficient amounts to ensure continuity. Development support needs to be provided for expanding new initiatives.
- IES leadership and staff should be adequate to ensure innovation and development of the program.
- Affiliated or jointly appointed faculty that participate in IES programs should have formalized tenure and promotion criteria that recognizes the importance and value of their interdisciplinary research, IES teaching, service, and outreach activities. There should be opportunities for all faculty to devote some proportion of their efforts to interdisciplinary programs.
- Clear guidelines for retention, tenure, and promotion should be developed for all faculty that participate in IES programs.
According to Dr. Mulkey, “the evidence shows that higher education has largely failed in its ethical obligation to prepare students to face the sustainability challenges of the coming decades. The present crisis in higher education offers an opportunity to realign institutional priorities with the overarching mission to maintain and renew civilization.” Now is the time to make a difference and educate future generations about what may be the world’s most important battle.