Urbanization and plant invasion impacts on tree morphology, physiology, and biochemistry. We are studying how potential urbanization pressures (e.g., soil heavy metals) affect the morphological, physiological, and biochemical response of red maple trees in urban forests in Newark, DE and Philadelphia, PA. Furthermore, we are exploring the impacts of nonnative invasive shrubs on adult trees performance.


Verifying a plant productivity index. Literature citations of Lepidoptera host plants indicate that plant genera in North America differ widely in their ability to support caterpillars (Tallamy and Shropshire 2009). These differences allow plants to be ranked in terms of their ability to generate the caterpillars that are primary drivers of many terrestrial food webs. If verified, such rankings will be useful in restorations and residential landscaping across the country. Ongoing studies in FRAME sites are ‘ground truthing’ the accuracy of Lepidoptera Productivity Indices generated by host record plant rankings by measuring the abundance and diversity of Lepidoptera in plots that vary in the biomass of highly ranked plants.

 The effect of urbanization and plant invasion on vegetation composition and diversity.  We are evaluating the composition, species richness, and similarity of adult trees and understory shrubs/saplings within and across 38 FRAME sites that span a gradient of urbanization intensity and plant invasion. Results from this work will demonstrate the magnitude of urbanization or plant invasion impact on vegetation dynamics as well as provide a basis for further studies on ecosystem function and plant-soil interactions across these forest fragments.

 Evaluating urbanization pressure and tree species effect on soil carbon, nitrogen and microbial community composition. We are assessing whether two tree species with differing canopy structures alter soil carbon (C) and nitrogen (N) stocks within both surface (< 20 cm) and subsurface (> 20 cm) soils across an urbanization gradient. Furthermore, since microbial communities are highly dependent on soil C and N additions as well as alterations in moisture and temperature, we expect to observe shifts in both bacterial and fungal community dynamics.

Testing the effects of invasive plant removal on plant species composition, regeneration and soil nutrient cycling. In fall 2017, we will initiate an invasive plant removal experiment followed by cost-effective, easy-to-implement treatments with the goal of reducing secondary plant invasion and improving soil quality. We will study plant species composition, soil nutrient cycling, and soil microbial community composition in order to assess the effectiveness of the post-removal treatments. Results from this work will inform management practices for private and public land owners and managers.

Relationships Between Brood Parasitism and Nestling Diet. The first project to take place within the FRAME sites is an exploration of interactions between parasitic cowbirds, invertebrate prey, and native songbirds. This study also takes advantage of the long-term bird data available for the FRAME sites.

Publication. 2015: Is brood parasitism related to host nestling diet and nutrition? – Zachary S. Ladin, Vincent D’Amico, Deb P. Jaisi, and W. Gregory Shriver  – Advances in Ornithological Research.

 The Effects of Nonnative Plant Invasion on Disease Transmission by Black-legged Ticks.  We are studying the impact of nonnative, invasive understory plants on local tick populations and the behavior of disease-carrying bird and mammal hosts, and how these effects interact to determine overall disease risk. Results of this work will inform a predictive model to aid land managers in developing strategies to reduce human disease risk while maintaining healthy forest ecosystems in urban communities.

Publication. 2016: Scale-dependent effects of nonnative plant invasion on host-seeking tick abundance. Solny Adalsteinsson, Vincent D’Amico, W. Gregory Shriver, Dustin Brisson, and Jeffrey Buler, Ecosphere.

Baby catbirds at EW  Population Dynamics of Neotropical Migrant Bird Species. An investigation into how urbanization and forest fragmentation are impacting wood thrush, a regionally declining neotropical migratory songbird. Using a combination of traditional and molecular techniques, we are exploring population genetics and dietary constraints in order to provide critical insight toward future management of small urban forest fragments.
Publication. Long-term dynamics in local host-parasite interactions linked to regional population trends. Zachary S. Ladin, Vincent D’Amico, Jan M. Baetens, Roland Roth and W. Gregory Shriver, Ecosphere.

The Effect of Urban Forest Quality and Composition on Occupancy and Abundance of Long-horned Beetles. We are evaluating the abundance and species richness of beetles in the family Cerambycidae in FRAME sites and other forest fragments in northern Delaware, and relating these data to site covariates across a range of conditions.

Publication. 2015: Species Richness and Phenology of Cerambycid Beetles in Urban Forests – Kaitlin Handley, Judy Hough-Goldstein, Larry Hanks, Jocelyn Millar and Vincent D’Amico – Annals of the Entomological Society of America.

Publication. 2016: Range of Attraction of Pheromone Lures and Dispersal Behavior of Cerambycid Beetles – Emily Dunn, Judy Hough-Goldstein, Larry Hanks, Jocelyn Millar and Vincent D’Amico – Annals of the Entomological Society of America.

The Effect of Landscape and Microhabitat Variables on Reptile and Amphibian Occupancy and Density.  This study is investigating the factors causing differences we have observed in presence/absence, density, and diversity  of herptofauna species in a fragmented landscape.
Gastropod and Arthropod Biodiversity in Urban Forests. Snail species and arthropod families in 32 mid-Atlantic forest fragments and riparian buffers are being catalogued, and their diversity and abundance related to soil, plant, and human usage variables.