Clark Lab

ENV323/623 is in Kruger National Park this week studying biodiversity and climate change. Only in the last 10,000 years have humans interacted with biodiversity in the absence of megafauna. This week students embedded with trophic diversity intact. The student blog is here.

Contributors are Francesca Chiappetta, Yikai Jing, Grace Tregidgo, Yu Hai, Jacob Carnes, Xuening Tang, Eliza Carter, Erel Amit, Bryan Graybill, Yuntian Bi, Natalie von Turkovich, Ross Fly, Matt Morris, Meech Carter, Nat Blackford, Elise Boos, Marisa Fajardo, Chloe Ochocki, Sara Haas, Sasha Iturralde, and Miao Hu

Admin by Eliza, Meech, and Sasha

Come out to engage with our students on 21st century forests and climate change! More info here.

Combining datasets helps identify biodiversity threats–if we can account for their different observation biases. eBird is a citizen science project with variable geographic coverage and observer effort. The Breeding Bird Survey (BBS) is a structured survey repeated each year. Together, they offer a massive resource on bird distribution and abundance. To combine them, we have to account for variation in habitat, time of day, observer effort and expertise (many eBirders are novices), and even the tendency of different species to be observed together.

The differences can be substantial. BBS observers count more species per observation effort, especially species that are common and detected by sound. eBirders count more “popular” and wetland species. Species typically identified by sound are reported more at sunrise than late morning. This knowledge of their biases is now being used to synthesize data from both sources.

Scher, C.L. and J.S. Clark. 2023. Species traits and observer behaviors that bias data assimilation and how to accommodate them. Ecological Applications, in press.

Reliable estimates of small mammal abundances are important for understanding community interactions. While capture–recapture estimates of absolute abundance are preferred, indices of abundance continue to be widely used. Calibrating with absolute abundance can improve these indices, but their reliability across years, sites, or species is unclear. We used the US National Ecological Observatory Network capture–recapture data for 63 small mammal species over 46 sites from 2013 to 2019… [more]

Monitoring small mammal abundance using NEON data: are calibrated indices useful?

Get access

Arielle W Parsons, James S Clark, Roland Kays

Journal of Mammalogy, gyac096, https://doi.org/10.1093/jmammal/gyac096

Understanding how communities respond to environmental change is frustrated by the fact that both species interactions and movement affect biodiversity in unseen ways. Tang et al. show that combined effects of species interactions and movement can be estimated for eBird data. [more]

Tang, B., J.S. Clark, P.P. Marra, and A.E. Gelfand. 2022. Modeling community dynamics through environmental effects, species interactions and movement. Journal of Agricultural Biological and Environmental Statistics, https://doi:10.1007/s13253-022-00520-3.

December 3^rd from 9AM-12PM

This workshop will be centered around ecological research and entails (1) an overview lecture by Dr Katti about the tenets of decoloniality in research, (2) jigsaw-style breakout sessions to discuss how these tenets connect to individual research, and (3) a final discussion and debrief. Breakfast, coffee, and snacks will be provided. Contact mes114@duke.edu for any questions or concerns.

Register by Thanksgiving HERE: https://forms.gle/rnPWMGpVhBNLHsJ5A

We will also be asking all those registered to re-confirm whether they will be attending in-person (likely at the Forest History Society) or virtually (over Zoom).

New for Spring 2023: Ecological Diversity and Climate Change (Environ 623/323, spring 2023)

Evaluate the science of biodiversity and climate change, including changes happening now, in the past, and what we can expect in the future.  The issues are focused by three contrasting case studies, including the field trip to Kruger National Park, South Africa, during spring break. Topics include woodland diebacks, intensifying drought, increased wildfire, insect and pathogen outbreaks, and poleward migrations of populations. We take a food-web approach, considering how species interactions respond dynamically to global change. Class activities include lectures, working group collaborations, class discussions, and the field trip. Analytical tools used to quantify change include data manipulation in R, including data sets collected during the course. Examples include population size and growth, regression, GLMs, and species distribution modeling. Prerequisites: statistics.

Climate change threatens species worldwide. At the Nicholas School, we’re creating new geospatial tools that boost their odds of survival…[more]

Lauren and Miao join us as new PhD students in the lab, entering the programs in NSOE (Miao) and University Program in Ecology (Lauren)

Bill Schlesinger and Bev Law wrote and gathered consensus for a letter to USFS and BLM as part of their planning for the executive order on conservation of old-growth forests. Their op-ed on The Hill is here.

“For free-roaming cats there is no animal more dangerous than the coyote” [one of our camera traps in Duke Forest appearing in the German press–Roland Kays interview]

A new collaboration to understand forest regeneration and climate change will be led by Jim Clark, in collaboration with University of California Merced, University of California Berkeley, University of Michigan, and the North Carolina Museum of Natural History. The award will involve sampling seed production and wildlife populations across the continental US.

The sustainability of North American forests depends on seed production by trees and the seedlings that must establish the next generation. For most of North America, neither the amounts of seed that are produced, nor how much of that seed survives to become future forests is known. Planning for climate change requires this knowledge to anticipate tree species migrations and its impacts on the birds and mammals that depend on forests for habitat and food. This study combines continental scale tree fecundity estimates with a new generation of monitoring and synthesis methods for integrating tree fecundity, seedling success, and its impacts on animal consumers. The study will quantify current trends across the continent, the changes in forests that are happening now, and the habitat changes that are causing them. [more]

Maggie collaborated using gjamTime to understand dynamic species interactions in response to climate change. Density-dependent shifts in competitive interactions drove long-term changes in abundance of species-groups under global change while counteracting environmental drivers limited the growth response of the dominant species through density-independent mechanisms. Furthermore, competitive interactions shifted with the environment, primarily with nitrogen and drove non-linear abundance responses across environmental gradients [more]

 

Collins, C.G., Elmendorf, S.C., Smith, J.G., Shoemaker, L., Szojka, M., Swift, M., and K. N. Suding. 2022. Global change re-structures alpine plant communities through interacting abiotic and biotic effects Ecology Letters, 25, 1813-1826. https://doi.org/10.1111/ele.14060

Luke Waylon Luongo emerged on June 15th, weighing 7 lbs 13 oz and 19 inches tall, everyone doing great.

Becky defended her PhD in the Department of Statistical Science, advised by Alan Gelfand and Jim Clark. She next heads to a tenure track faculty position at Middlebury College.

Becky was recognized by the American Statistical Association for her paper, “Modeling spatially biased citizen science effort through the eBird database” in Environmental and Ecological Statistics. This paper also received the Best Award from the Department of Statistical Science.

Tang, B., J. S. Clark, and A. E. Gelfand. 2021. Modeling spatially biased citizen science effort through the eBird database. Environmental and Ecological Statistics, https://doi.org/10.1007/s10651-021-00508-1.

New research finds that North Atlantic right whales with severe injuries are more likely to die than those with minor ones, making entanglements the leading cause of serious injury and mortality in the critically endangered species. The research underscores the urgent need for changes to the fishing industry as the species, with an estimated population of less than 350 individuals, faces extinction. The study, published in Conservation Science and Practice, also found that sub-lethal effects on reproductive success are more pronounced than previously recognized. Read more…

This summer, there are five people working with Renata’s urban tree-health study, two in Chicago and three in Durham. The three Durham technicians are Chloe Schueller, Maggio Laquidara, and Lucie Ciccone. They will each examine different aspects tree health across the city of Durham and the Duke campus. Topics include impacts of maintenance on tree health, urban bird habitats, and the social and political factors that influence tree health in cities. Renata’s site includes bios.

POLONEZ BIS is co-funded by the European Commission and the Polish National Science Centre under the Marie Skłodowska-Curie COFUND grant. In three calls to be announced in 2021 and 2022 the programme will recruit 120 experienced researchers from all over the world. They will move to Poland for 24 months to conduct their basic research in public or private institutions of their choice. Valentin will be collaborating with Michal Bodgziewicz and Jim Clark on masting dynamics.

Tong will start at Penn State University in October 2022. Meanwhile, he’ll complete projects here are Duke focused on remote sensing, tree fecundity, and ground beetle ecology. His highly productive postdoc years include the publications listed here.

Some of us trekked down the Black River to trees aged by Dave Stahle at > 2600 yr. Led by Don of Mahanaim Adventures, we entered the ancient stand from upstream. Continuing drought in the Southeast left us to portage the swamp interior. Many large trees have snapped in this hurricane-battered watershed, but blowdowns within the cypress groves are rare. Knees emerge from a tangle of roots that appears to anchor the entire stand against windthrow.