Research
I am interested in three main areas of ecology: ecosystem ecology, populations, and global anthropogenic change. I use observational, experimental, and computational approaches to answer questions in these areas and move research on ecological theory and application forward.
Current Research
1. Passive Subsidies Passive subsidies are resources moved from one ecosystem to another by gravity or air/water currents. Much of my dissertation focused on this, particularly the input of leaves from forest into ponds. I examined how the input of leaves to ponds affected the reciprocal export of frog biomass along a gradient in primary productivity. I found that inputting leaves did increase the export of frog biomass. However, contrary to my predictions, I also found that frog biomass decreased with increases in primary productivity. This may be due to differences in diet or changes in temperature with canopy.
Related Publications:
-Smith, L.L., A.L. Subalusky, C.L. Atkinson, J.E. Earl, D.M. Mushet, D.E. Scott, S.L. Lance, and S.A. Johnson. 2019. Biological connectivity of seasonally ponded wetlands across spatial and temporal scales. Journal of the American Water Resources Association 55(2):334-353.
-Earl, J.E. and P.A. Zollner. 2017. Advancing research on animal-transported subsidies by integrating animal movement and ecosystem modeling. Journal of Animal Ecology 86(5):987-997. Abstract
-Earl, J.E. and R.D. Semlitsch. 2015. Effects of tannin source and concentration from tree leaves on two species of tadpoles. Environmental Toxicology and Chemistry 34(1): 120-126. Abstract
-Earl, Castello, Cohagen, and Semlitsch. 2014. Effects of subsidy quality on reciprocal subsidies: how leaf litter species changes frog biomass export. Oecologia 175(1): 209-218. Abstract
-Earl and Semlitsch. 2013. Spatial subsidies, trophic state, and community structure: Examining the effects of leaf litter on ponds. Ecosystems 16(4): 639-651. Abstract
-Earl and Semlitsch. 2012. Reciprocal subsidies in ponds: Does leaf input increase frog biomass export? Oecologia 170(4): 1077-1087. Abstract
-Earl, Cohagen, and Semlitsch. 2012. Effects of leachate from different species of tree leaves and grass litter on tadpoles. Environmental Toxicology and Chemistry 31(7): 1511-1517. Abstract
-Earl, Luhring, Williams, and Semlitsch. 2011. Biomass export of salamanders and anurans is affected differentially by changes in canopy cover. Freshwater Biology 56(12): 2473-2482. Abstract
2. Effects of Animal Movement Strategies on Subsidy Deposition Nutrients are transported between ecosystems when animals have a greater mortality rate in one ecosystem or forage in one environment and defecate in another. This nutrient deposition can supplement the nutrient supply, supporting ecosystem services. Animals can also transport contaminants. These positive and negative effects of animal transported subsidies emphasize the need to predict the spatio-temporal deposition of subsidies. I am currently investigating how different animal movement strategies determine the extent and magnitude of subsidy deposition. I am using individual based models to examine this theoretically, with plans to test these modes with field studies, particularly with amphibians.
Related Publication:
-Bampoh, D., J.E. Earl, and P.A. Zollner. 2020. Simulating the relative effects of movement and sociality on the distribution of animal-transported subsidies. Theoretical Ecology, published online. Abstract.
-Bampoh, D., J.E. Earl, and P.A. Zollner. 2019. Examining the relative influence of animal movement patterns and mortality models on the distribution of animal transported subsidies. Ecological Modelling 412: 108824. Abstract.
-Earl and Zollner. 2014. Effects of animal movement strategies and costs on the distribution of active subsidies across simple landscapes. Ecological Modelling 283: 45-52. Abstract
4. Effects of Ranavirus on Population Dynamics I am interested in the potential for different stressors to affect population dynamics. I have created population models for the endangered dusky gopher frog, boreal toads, and wood frogs to examine whether the introduction of the pathogen Ranavirus could possibly cause population extinction. I found that ranavirus could increase extinction probabilities, speed up extinction times, and cause population declines in isolated populations of wood frogs. This work is in collaboration with Matt Gray and Bill Sutton.
Related Publications:
-Duffus, A., T. Garner, R. Nichols, J. Standridge, and J.E. Earl. 2019. Modelling ranavirus transmission in populations of common frogs (Rana temporaria) in the United Kingdom. Viruses 11(6): 556. Available open access.
-Gray, M.J., J.L. Brunner, J.E. Earl, and E. Ariel. 2015. Design and Analysis of Ranavirus Studies: Surveillance and Assessing Risk. In M.J. Gray and V.G. Chinchar, eds. Ranaviruses: Lethal Pathogens of Ectothermic Vertebrates. Springer. Book available open access.
-Earl, J.E., and M.J. Gray. 2014. Introduction of Ranavirus to isolated Wood Frog populations could cause local extinction. EcoHealth 11(4): 581-592. Abstract
-Earl, J.E., J.C. Chaney, W.B Sutton, C.E. Lillard, A.J. Kouba, C. Langhorne, J. Krebs, R.P. Wilkes, R.D. Hill, D.L. Miller, and M.J. Gray. 2016. Ranavirus could facilitate local extinction of rare amphibians. Oecologia182(2): 611-623. Abstract
5. Effects of Forestry Practices on Wildlife One of the great challenges of forest management is balancing the goals of certain management practices with the conservation of biodiversity. Certain forestry practices are known to have negative impacts on amphibian populations. One of my research goals is to provide information to better understand how different forestry practices affect amphibians and to adjust these practices to better conserve amphibians while still meeting the goals of forest management. To this end, I have investigated the importance of forestry practices in the larval and juvenile habitat to an important vital rate whether forestry practices or associated microhabitat or microclimate variables have higher predictive power for juvenile amphibian survival and growth.
Related Publications:
-Earl, J.E., E. Harper, D.J. Hocking, M.S. Osbourn, T.A.G. Rittenhouse, M. Glennie*, and R.D. Semlitsch. 2017. Relative importance of timber harvest and habitat for reptiles in experimental forestry plots. Forest Ecology and Management 402: 21-28. Abstract
-Earl, J.E., E. Harper, D.J. Hocking, M.S. Osbourn, T.A.G. Rittenhouse, and R.D. Semlitsch. 2016. Effects of timber harvest on small mammals in experimental forestry plots. Animal Biology 66: 347-362. Abstract
-Earl, J.E. and R.D. Semlitsch. 2015. Importance of forestry practices relative to microhabitat and microclimate changes for juvenile pond-breeding amphibians. Forest Ecology and Management 357: 151-160. Full text
-Earl, J.E., and R.D. Semlitsch. 2013. Carryover effects in amphibians: Are characteristics of the larval habitat needed to predict juvenile survival? Ecological Applications 23(6): 1429-1442. Abstract
Fig. 1. In pond mesoscosms with different species of leaf litter, increased tannins reduce tadpole survival and indirectly reduce body mass reducing the amphibian biomass export from ponds to the surrounding terrestrial ecosystem (from Earl et al. 2014. Oecologia).
