Life Sciences Commons^™

Repeat Disturbances Have Cumulative Impacts On Stream Communities, Jessica M. Haghkerdar, Jack R. Mclachlan, Alexis Ireland, Hamish S. Greig

Biology and Ecology Faculty Scholarship

1. Climate change has altered disturbance regimes in many ecosystems, and predictions show that these trends are likely to continue. The frequency of disturbance events plays a particularly important role in communities by selecting for disturbance -tolerant taxa.

2. However, ecologists have yet to disentangle the influence of disturbance frequency per se and time since last disturbance, because more frequently disturbed systems have also usually been disturbed more recently. Our understanding of the effects of repeated disturbances is therefore confounded by differences in successional processes.

3. We used in -situ stream mesocosms to isolate and examine the effect of disturbance …

Strong Zonation Of Benthic Communities Across A Tidal Freshwater Height Gradient, Jack R. Mclachlan, Jessica M. Haghkerdar, Hamish S. Greig

Biology and Ecology Faculty Scholarship

Trade-offs associated with environmental gradients generate patterns of diversity and govern community organisation in a landscape. In freshwaters, benthic community structure is driven by trade-offs along generally orthogonal gradients of habitat permanence and predation—where ephemeral systems are physiologically harsh because of drying stress, but inhabitants are less likely to be under the intense predation pressure of more permanent waterbodies. However, in tidal freshwaters, these two stressors are compounding, and the trade-offs associated with them are decoupled.
2. We investigated benthic community structure in a tidal freshwater habitat. These communities experience a suite of conditions atypical for a freshwater habitat: twice-daily …