Research

Seasonal community dynamics

Nearly all ecosystems show seasonality in their community dynamics. The pattern of these seasonal dynamics may have wide-ranging implications for the ecology and evolution of communities in these ecosystems. I primarily use long term datasets of community composition to investigate these patterns: how seasonal and variable are communities experiencing different abiotic (ex. temperature, precipitation) or biotic (ex. predation) seasonal regimes, and how does this affect the longer term variability, resilience, and diversity of communities?

My current work on these questions is mostly in lakes, where I am using zooplankton timeseries from coastal Connecticut to investigate the effects of seasonality in predation by migratory and resident forms of a zooplanktivorous fish (Alewife, Alosa pseudoharengus). I am also using long term zooplankton datasets from a set of globally distributed lakes to investigate how basic patterns of seasonal and interyear variability in zooplankton change across lakes with different abiotic seasonal regimes. We are finding that growing season length and maximum temperature, more than temperature seasonality itself, are strong predictors of zooplankton seasonality – suggesting a larger role for seasonal successional dynamics than temperature niche in creating these biotic seasonal regimes.

Average growing season length (days above a temperature threshold) versus species seasonality (how unevenly zooplankton abundances are distributed throughout the year). Each point is the average value for one lake.

Ecology and evolution of phenology

Phenology and the temporal niche are fundamental aspects of the biology of species living in a seasonal environment, which differ from population dynamics in that they are typically a cued, adaptive response to a predictable environment, both biotic and abiotic. I am particularly interested in how competition and other species interactions structure the distribution of phenologies within a community.

I am studying these questions at the population level in a single species, the phantom midge (Chaoborus punctipennis). I am investigating the effects of seasonal fish presence, via direct predation and through competition for zooplankton, on the phenology of this species in six lakes. I am also creating a species-level, weekly timeseries of adult abundance of the highly diverse Chironomidae (non-biting midges) at three lakes to study how the diet and habitat of these species impacts their phenological distributions within and between functional groups.

Adult Chironomidae from a malaise trap sample.

Publications

Spear, M. J., P. A. Wakker, T. P. Shannon, R. L. Lowe, L. E. Burlakova, A. Y. Karatayev, and M. J. Vander Zanden. 2022. Early changes in the benthic community of a eutrophic lake following zebra mussel (Dreissena polymorpha) invasion. Inland Waters 12:311–329.