Research

My research centers on identifying patterns and mechanisms of biodiversity loss and highlighting opportunities for maintaining biodiversity in human-altered landscapes. Specifically, I aim to understand 1) how major drivers of environmental change redistribute genes, individuals, and species, 2) which traits mediate responses to these drivers, and 3) how key traits vary across space and time. By examining responses to environmental change across taxonomic groups, levels of biological diversity (from alleles to communities), and spatial scales (from microhabitats to landscapes), I try to identify general principles that explain why some species decline while others persist in an increasingly human-altered world. To address these challenges, I combine local-scale field experiments, landscape-scale investigations, and global-scale syntheses.

 

Behavior and local mechanisms underlying responses to landscape change:  

 

The cumulative outcomes of individual survival, movement, and behavior ultimately scale up to shape population-level responses to global stressors. Studies of applied behavioral ecology represent one facet of my research that has lent itself to the inclusion of undergraduate students in scholarly activity. For example, my students and I have conducted experimental translocations to evaluate variation in homing success (as a proxy for dispersal success) of poison frogs across forest and pasture habitats (Nowakowski et al. 2013). We have also examined behavioral responses of poison frogs to herbecide olfactory cues, which could have implications for movement and habitat selection in areas heavily treated with agrochemicals (Farabaugh and Nowakowski 2014).

 

From local mechanisms to landscape patterns of diversity:

 

Local processes, in part, shape patterns of biodiversity across the landscape. In Costa Rica, I investigated the effects of cattle pastures and heart-of-palm plantations on the movement (connectivity) and diversity of amphibians. I used information from field experiments in these land uses to account for local mechanisms in models of landscape connectivity (i.e., movement among populations). I then used these connectivity models to explain patterns of species and genetic diversity of amphibians in forest remnants. To date, some lessons from this work include the following: 1) Widespread pastures are less hospitable to amphibians than heart-of-palm plantations; pastures reduce abundances, diversity, and gene flow compared to other land-cover types, in part, owing to their extreme microclimates (Kurz et al. 2014; Nowakowski et al. 2015a; Nowakowski et al. 2015b). 2) However, remnant single trees in crop fields or pastures provide cooler microclimates and act as small habitat patches for some species; single trees should be actively retained to increase wildlife friendliness of pastures and cultivated lands (Robinson et al. 2013). My recent work has focused on how thermal landscape variability (i.e., temperature variation among habitats) and species-specific thermal biology may interact to reshape assemblages in response to both land-use and climate change.

 

Global-scale quantitative syntheses of threats to biodiversity:

 

Quantitative syntheses allow us to draw generalizable conclusions about global change effects on biodiversity. I have helped design and conduct multiple syntheses aimed at 1) understanding the effects of land use on vertebrate populations and assemblages (Watling et al. 2011: Global Ecology and Biogeography; Thompson et al. 2015: Conservation Biology) and 2) determining which species traits best explain susceptibility of amphibian species to habitat loss and the global chytridiomycosis pandemic (Nowakowski et al. 2017: Global Ecology and Biogeography; Nowakowski et al. 2016: Ecology Letters).