Research Interests:

I am an experimental field ecologist and my students have been working in the understorey of the Boreal Forest (southwestern Yukon, Canada) since 1990. In addition, from 1992-1999 I did collaborative research with Deborah Goldberg in the Negev Desert (Israel), and over this past few years I have (or had) students in Israel, the Garry Oak ecosystem of southern British Columbia, and the Interior forests and grasslands of British Columbia. We focus on two primary questions: (i) how are plant communities structured, and (ii) how do they function?

The first question is addressed by two major sets of studies. First we are testing if the plant community is structured primarily by nutrient limitation, by herbivory, or by their interaction. Our experiments manipulate soil nutrient levels and herbivore levels, and we then monitor the consequences on individual plant species, populations, and communities. Second, we are testing hypotheses about the impacts of competition on community structure and if the magnitude of these impacts change in predictable ways along productivity gradients?

The second question is also addressed by major two sets of studies. First, we are using "functional group knock-out" experiments in which selected components of a plant community are removed and the consequent changes in community dynamics and ecosystem function monitored. Second, by simulating species loss from natural systems, in conjunction with seed and seedling additions, we can determine the effect of plant species identity on invasibility of a community, and the effect of the level of the disturbance of the community on subsequent invasion.

Boreal Forest, Yukon

Some of our Research Sites in the Southern Yukon

TURKINGTON, R. Top-down and bottom-up regulation of vegetation. An essay review (accepted Canadian Journal Botany)

RAJANIEMI, T.K., TURKINGTON, R., & D.E. GOLDBERG. Population- and community-level consequences of regulation in an annual plant community under different resource levels. (accepted Journal of Vegetation Science)

FRASER, L.H., GREENALL, A., CARLYLE, C., TURKINGTON, R. & C.R. FRIEDMAN. Adaptive phenotypic plasticity of Pseudoroegneria spicata: response of stomatal density, leaf area and biomass to changes in water supply and increased temperature. (Annals of Botany)

KARST, J., JONES, M.D. & R. TURKINGTON. 2009. Ectomycorrhizal colonization and intraspecific variation in growth responses of lodgepole pine. Plant Ecology 200:161-165.

SHARAM, G., SINCLAIR, A.R.E. & TURKINGTON, R. & A.L. JACOB. 2009. The savanna tree Acacia polyacantha facilitates the establishment of riparian forests in Serengeti National Park, Tanzania. Journal of Tropical Ecology 25:31-40.

TREBERG, M.A. & R. TURKINGTON. 2008. How to grow, propagate and kill some of the native plants in the Kluane region, southwestern Yukon. Davidsonia 19:42-53.

SECCOMBE-HETT, P. & R. TURKINGTON. 2008. Summer diet selection of snowshoe hares: a test of nutritional hypotheses. Oikos 117:1874-1884.

LORTIE, C.J. & R. TURKINGTON. 2008. Species-specific positive effects in an annual plant community. Oikos 117:1511-1521.

KARST, J., MARCZAK, L., JONES, M.D. & R. TURKINGTON. 2008. The mutualism-parasitism continuum in ectomycorrhizas: a quantitative assessment using meta-analysis. Ecology 89:1032-1042.

MacDOUGALL, A.S. & R. TURKINGTON. 2007. Does the type of disturbance matter for restoring disturbance-dependent savanna ecosystems? Restoration Ecology 15:263–272.

MDUMA, S.A.R, SINCLAIR, A.R.E. & R. TURKINGTON. 2007. What is the role of seasonality and synchrony in reproduction of savanna trees in Serengeti? Journal of Ecology 95:184-196.

SHARAM, G., SINCLAIR, A.R.E. & R. TURKINGTON. 2006. Establishment of broad-leaved thickets in Serengeti, Tanzania: the influence of fire, browsers, grass competition and elephants. Biotropica 78:599-605.

MacDOUGALL, A.S. & R. TURKINGTON. 2006. Dispersal, competition, and shifting patterns of diversity in an degraded oak savanna. Ecology 87:1831-1843.

RAJANIEMI, T.K., GOLDBERG, D.E., TURKINGTON, R., & A.R. DYER, A. 2006. Quantitative partitioning of regional and local processes shaping regional diversity patterns. Ecology Letters 9:121-128.

MacDOUGALL, A.S, BOUCHER, J, TURKINGTON, R. & G.E. BRADFIELD. 2006. community-level patterns of plant invasion across a broad-scale stress gradient. Journal of Vegetation Science 17:47-56.