Seminário de Biomatemática 4 de Novembro 2008, 16h00 Abstract: Many organisms live in environments with a predominantly unidirectional flow such as streams and rivers. Alterations of natural flow regimes (e.g., due to human management or global warming) put biological populations at risk. We consider simple mathematical models of reaction-diffusion-advection type describing the spatiotemporal dynamics of predator-prey communities. If the advective flow speed is too high, populations will be washed out. However, we will derive conditions when the prey and/or the predator population can persist and invade upstream, based on a travelling wave approach. The results presented can provide a useful tool in the assessment of "instream flow needs", estimating the flow speed necessary for preserving riverine populations. The impact of temporal and spatial heterogeneity will be briefly taken into account as well as the potentially stabilising role of advection in bounded domains. | back |