Current Projects:
Effects of shrub encroachment on habitat suitability for arctic ground squirrels (Urocitellus parryii)
I am assessing the role of habitat structure and forage quality in
determining arctic ground squirrel abundance and distribution. Work has included studies of behaviour (giving up density), individual condition, juvenile growth rates and population dynamics and now extends these ideas to larger scales. I am particularly interested in the scale at which
vegetation structure has most important effects on distribution. In summer 2013 I will be conducting a field project in Denali National Park assessing how these factors affect distribution and abundance. As well as
investigating the role of habitat structure and forage on this species I intend
to investigate facilitative effects of local colonies on each other and how
this interacts with ability to persist in lower visibility habitat. In summer 2013 I conducted a field project in Denali National Park.
Effects of predators and habitat structure on global distributions of ground-dwelling sciurids
Encroachment of shrubs in to more open grasslands and tundra is changing habitat structure for many species. I am comparing factors determining distribution of ground dwelling sciurids with particular focus on the role of habitat structure in determining distribution and effects of body mass and sociality on this response.
In addition, across their range, these species are affected by different pressures to accumulate mass, and trade-offs between predation risk and forage availability. Many ground dwelling sciurids inhabit highly seasonal environments either due to strong seasonality in temperature or rainfall patterns. Hibernation or aestivation occurs in most species and will affect time available to accumulate mass. Using data on active season duration, investment in reproduction and mass gain during the active season I intend to further investigate the effects of these pressures on strength of response to habitat structure and forage availability.
In addition, across their range, these species are affected by different pressures to accumulate mass, and trade-offs between predation risk and forage availability. Many ground dwelling sciurids inhabit highly seasonal environments either due to strong seasonality in temperature or rainfall patterns. Hibernation or aestivation occurs in most species and will affect time available to accumulate mass. Using data on active season duration, investment in reproduction and mass gain during the active season I intend to further investigate the effects of these pressures on strength of response to habitat structure and forage availability.
Temporal trends in flowering phenology and flower output in arctic plants
Using long-term observations of flowering from Zackenberg, Greenland, I am investigating the effects on phenology and climate on flower output in Dryas integrifolia/octopetala, Cassiope tetragona, Salix arctica, and Papaver radicatum. Using HOF models to fully characterise different characteristics of population-level flowering curves (flowering onset, peak flowering, flowering end, duration of flowering, skew in flowering), I am examining the trends in these aspects of phenology with particular focus on skew in flowering. I am then considering the relationship between aspects of phenology and flower output and climatic causes of these trends (e.g. cold limitation, light limitation).
Large scale approaches to understanding the ecosystem role of social herbivorous burrowing mammals
Using mammal community data from across North America I am considering the ecosystem role of social herbivorous burrowing mammals. I am particularly interested in whether sociality or burrowing behaviour are associated with stronger effects of prey on predator biomass or stronger top down effects of predators on prey biomass. I am also interested in exploring other approaches to examining the ecosystem role on other part of the system.