Research

Below are summaries of current and completed projects.

Ongoing research: Island biogeography

My students and I conduct research on the ecology, distribution, and conservation of plant species and ecosystems using field studies, laboratory analyses, statistical analyses, and GIS/remote sensing. The majority of my biogeography work has been on temperate islands in the Great Lakes and tropical islands in the eastern Pacific Ocean. My research provides insights into how shoreline and island habitats will respond to forces such as competition from non-native plant species and fluctuating water levels, and provides recommendations for conservation strategies needed to ameliorate the effects of such disturbances.

Biogeography of island flora in the Georgian Bay Biosphere Reserve, Lake Huron (Canada)

Little is known regarding the role of feedbacks between climate patterns, coastline geomorphology, and shoreline vegetation on species richness patterns on islands. We combine dendrochronological analyses, spatial analyses, soil analyses, and ecological analyses to examine the interplay of regional climate, water levels, soils, and forest dynamics on plant species richness and composition patterns. Spatiotemporal forest dynamics, soil characterization comparisons between recently emerged and established substrates and tree-ring reconstructions are analyzed in relation to vegetation surveys of plant species richness and composition to shed light on the applicability of the prevailing model of island biogeography in areas with fluctuating water levels. With Georgian Bay water levels at historic lows in 2006 and currently at higher than average levels, island areas and shoreline morphologies are in flux. Shorelines of islands in The Massasauga Provincial Park are varied (e.g. steep cliff, sandy beach, cobble shore) and therefore affect the colonization and persistence ability of plants differently. Examination of the dynamic terrestrial-aquatic interface in the Great Lakes is pertinent to many of the conservation and policy issues in the region today.

Main research themes:

    • Role of effective isolation on plant species richness patterns: new perspectives (Diver 2008)
    • Influence of water-level changes on island ecosystems (Diver 2014; Edgley 2014; Sinkler 2014; Steinfeld 2017)
    • Spatiotemporal distributions of non-native plant species
    • Dendrochronological analysis of insular forest stands in relation to climate and water-level fluctuations (Diver 2017; Bournival 2017; Kelly 2017)
    • Spatiotemporal forest dynamics (Diver 2009)
    • Long-term dynamics of the islands and their biota
    • Species-based approach to island biogeography theory

Students: Tessa Hill B.A. 2016 M.A. 2017, Ezra Steinfeld B.A. 2017, Matt Kelly B.A.  2017, William Speiser B.A. 2017, Leah Bournival B.A. 2017, Emilie Sinkler B.A. 2014, Ryan Edgley B.S. 2014, Tastea Kurtu B.A. 2014, Ariela Knight B.A. 2013, William Martin-Black B.A. 2012, Alex Gumpel B.A. 2011, Scott Williams B.A. 2008, Liz Strassman B.A. 2008


Diversity, spatial distribution, and conservation of the flora in the Coiba National Park and Special Zone of Marine Protection World Heritage Site (Republic of Panama)

The main objective of this project is to examine the diversity and distribution of flora in Coiba National Park and surrounding areas. The specific objectives are: (1) Inventory the vascular flora of islands not previously inventoried, which included 191 islands and islets in Coiba National Park and the areas of Bahia Honda, Gulf of Montijo. and offshore of Cerro Hoya National Park; (2) Create accurate shoreline maps of the islands using field and remote sensing data; (3) Examine species patterns in relation to prevailing and alternative models of island biogeography; (4) Calculate the potential loss of habitat and island area due to climate change; (5) Train Panamanian scientists (3 botany undergraduate students and 2 geography undergraduate students). Sea-level rise (SLR) scenarios are increasingly used to predict consequences of inundation on economic losses and human population displacement along coastal regions and on low-lying island nations. Research regarding consequences of SLR on biodiversity has typically been relegated to wetland ecosystems such as tidal marshes and mangroves. A need exists to assess ecological threats from SLR on insular biodiversity. Immersion of portions or total submersion of islands threatens future biodiversity in the region, especially in the case of endemic plant species losses. Our research has informed conservation measures in the park regarding vegetation management policies that take into account global climate change.

Main research themes:

    • Potential effects of sea-level rise on island ecosystems
    • Role of effective isolation on plant species richness patterns: new perspectives
    • Spatiotemporal distributions of endemic plant species

Students: Katie Toner B.A. 2020, Sora Akiyoshi B.A. 2014, Alexis Jiménez B.A. 2012, Julissa Domínguez B.A. 2012, Alex Gumpel B.A. 2011
Collaborator: Alicia Ibañez


 

Completed projects

Spatiotemporal patterns of reported black bear sightings in Connecticut, 2007-2019

Human-bear interactions in North America have increased over the past 50 years. The Wildlife Division of the Connecticut Department of Energy and Environmental Protection (DEEP) maintains citizen reports of black bear sightings, with publicly available datasets dating back to 2007. This study addressed the following research questions: (1) Is there a temporal pattern of black bear sightings in Connecticut? (2) What is the current geographic distribution of sightings? (3) Is the geographic pattern of sightings consistent over time? (4) What variables might account for any spatiotemporal trends in the data? The sightings per town data were mapped and analyzed in ArcGIS Online. Results indicate an overall increase in sightings over time with a hot spot of reported sightings in western Hartford and eastern Litchfield counties.

Student contributors: Fall 2019 E&ES 130 students


Ash decline versus hydrofracking: modeling habitat degradation of the cerulean warbler

The project analyzed the sustainability of an umbrella species in response to human-induced non-native species invasions and disturbances, specifically a habitat threat analysis of mature hardwood forest communities of the Finger Lakes Region (New York) that provide habitat for the cerulean warbler, a federally listed species of concern. The research involved habitat suitability models for the warbler species and habitat reduction models based on two potentially major disturbance agents in the region: ash decline (emerald ash borer) and forest fragmentation due to hydrofracking infrastructure (e.g. well pads, access roads). The emerald ash borer has caused massive die backs of ash tree species in the Great Lakes and Northeast regions. Hydraulic fracturing (i.e. hydrofracking) for Marcellus shale natural gas is currently not allowed in the region, but companies are acquiring leases in anticipation of policy changes. Both disturbance types can cause considerable habitat fragmentation but the models suggest that ash decline will pose a more significant threat. Models derived from the research could be applied to indicator species in other areas at risk of extensive ash decline.

Student: Mads O’Brien B.A. 2016


Climate change and autumn colors in New England’s forests

Around the globe, it is well recorded that earlier spring events are strongly correlated with rising temperatures, but the influence of climate change on the timing of autumn events is less well understood. Autumn senescence is the phenomenon in which deciduous trees lose their leaves, a period during which many species undergo a brilliant fall color display. The primary trigger of autumnal color is the shortening photoperiod, but other environmental factors may influence the quality of the color display. The primary environmental influences on the quality of the fall foliage display include temperature, sunlight, and moisture. Because changes in these environmental factors are linked with ongoing climate change, the future of fall color displays may be adversely affected. In Kyne & Diver (2012) we examine possible consequences of climate change on color change events and implications of a changing fall color regime on regional fall tourism. The current most pressing risks to the color displays in the forests of New England are severe weather events and climate-induced shifts in species distributions. As a result of actual or even perceived change, fall color tourism markets are expected to suffer.

Student: Amanda Kyne B.A. 2011


Homeless interactions with the built environment: A spatial pattern language of abandoned housing

Research demonstrates that homeless individuals use urban space in adaptive and endemic ways. Investigations at city and neighborhood scales would benefit from attention to homeless use of abandoned housing. In Kaplan et al. (2019) we employed the pattern language approach developed by Christopher Alexander for twenty-two abandoned houses in Newark, Ohio. We used statistical and geospatial data analyses to evaluate hypotheses related to prospect and refuge site qualities, accessibility and attractiveness to homeless persons, and the proximity of sites to resources. Factors related to prospect/refuge, accessibility, and resource proximity were consistent with the hypotheses. Results were grouped into four distinct patterns: ‘Hiding Places,’ ‘Welcome Mat,’ ‘Shelter (Un)becoming,’ and ‘Proximity to Resources.’

Student: Sarah Kafer, B.A. 2007
Collaborators: Abram Kaplan, Karl Sandin