Community ecology, environmental gradients, global change; aquatic ecology, freshwater invertebrates
My research uses freshwater ecosystems to understand how environmental gradients influence community structure and function. Specifically, my research focuses on three key questions: 1) How do disturbances influence community structure and dynamics? 2) How do local stresses modify the effects of global change on ecosystems? 3) What are the mechanisms underlying the effects of temperature changes on food webs? I approach these questions by using combination of observational studies, field manipulations, and mesocosm experiments to test hypotheses across spatial scales and levels of ecological complexity. My work is motivated by the view that revealing the mechanisms behind the environmental context of ecological processes is the key to developing the general understanding necessary to manage human impacts on ecosystems.
Atwood, T. B., E. Hammill, H. S. Greig, P. Kratina, J. B. Shurin, D. S. Srivastava and J. S. Richardson. 2013. Predators reduce CO2 emissions from freshwater ecosystems. Nature Geoscience. 6: 191-194. doi:10.1038/ngeo1734.Greig, H. S., S. A. Wissinger, and A. R. McIntosh. 2013. Top-down control of prey biomass increases with drying disturbance: an unexpected consequence of non-consumptive interactions? Journal of Animal Ecology. doi: 10.1111/1365-2656.12042.Shurin, J. B., J. Clasen, H. S. Greig, P. Kratina, and P. L. Thompson. 2012. Warming shifts top-down and bottom-up control of pond food web structure and function. Philosophical Transactions of the Royal Society B: Biological Sciences. 367: 3008-3017.Greig, H. S.*, P. Kratina*, P. L.Thompson, W. J Palen, J. S. Richardson, and J. B. Shurin. 2012. Warming, eutrophication and predator loss amplify subsidies between aquatic and terrestrial ecosystems. Global Change Biology. 18: 504-514. * Authors contributed equally.Kratina, P.*, H. S. Greig*, P. L Thompson, T. S. A. Carvalho-Pereira, and J. S. Shurin. 2012. Warming modifies trophic cascades and eutrophication in freshwater ecosystems. Ecology. 93: 1421-1430. * Authors contributed equally.Klemmer, A. J., S. A. Wissinger, H. S. Greig, and M. L. Ostrofsky. 2012. Strong single-species effects of a detritivore on multiple ecosystem processes. Journal of Animal Ecology. 81: 770-780. Highlighted feature on journal home page.Greig, H. S., D. K. Niyogi, K. L. Hogsden, P. G. Jellyman and J. S. Harding. 2010. Heavy metals: confounding variables in the response of New Zealand freshwater fish assemblages to natural and anthropogenic acidity. Science of the Total Environment. 408: 3040-3050.Greig, H. S. and S. A. Wissinger. 2010. Reinforcing biotic and abiotic time constraints facilitate the broad distribution of a generalist with fixed traits. Ecology. 91: 836-846.Wissinger, S. A., H. S. Greig, and A. McIntosh. 2009. Absence of species replacements between permanent and temporary lentic habitats in New Zealand. Journal of the North American Benthological Society. 28: 12-23.
Greig, H. S., and A. R. McIntosh. 2008. Density reductions by predatory trout increase adult size and fecundity of surviving caddisfly larvae in a detritus-based stream food web. Freshwater Biology 53: 1579-1591.
Wissinger, S. A., A. R. McIntosh, and H. S. Greig. 2006. Impacts of introduced brown and rainbow trout on benthic invertebrate communities in shallow New Zealand lakes. Freshwater Biology 51:2009-2028.
Greig, H. S., and A. R. McIntosh. 2006. Indirect effects of predatory trout on organic matter processing in detritus-based stream food webs. Oikos 112:31-40. Honourable mention, Best Publication by a New Researcher, New Zealand Ecological Society, 2008.
Wardhaugh, C. W., T. J. Blakely, H. S. Greig, P. D. Morris, A. Barnden, S. Rickard, B. Atkinson, L. L. Fagan, R. M. Ewers, and R. K. Didham. 2006. Vertical stratification in the spatial distribution of the beech scale insect (Ultracoelostoma assimile) in Nothofagus tree canopies in New Zealand. Ecological Entomology 31:185-195.
McIntosh, A. R., H. S. Greig, S. A. McMurtrie, P. Nystrom, and M. J. Winterbourn. 2005. Top-down and bottom-up influences on populations of a stream detritivore. Freshwater Biology 50:1206-1218.