Habitat selection and territorial behaviour
Habitat selection is critical in ecological theory and application because this behaviour is a primary way that mobile organisms adapt to changing environmental and ecological conditions. So a central dimension of my research has been the study of freshwater fish habitat selection and the identification of the factors that drive observed variability in selection patterns and the spatial and temporal scales they operate. Habitat selection represents a stable evolutionary strategy shaped by both density-dependent and independent (e.g., extreme flow events) selective forces. What are such forces? Using brown trout as a model system, my colleagues at the UCM and I have conducted over the years field studies to identify (1) the physical (geological, morphological and hydraulic) river features driving habitat selection variability among populations (Ayllón et al. 2009, 2010), and (2) the environmental (streamflow characteristics; Ayllón et al. 2014) and ecological (competition on resource use; Ayllón et al. 2013) determinants of seasonal and interannual habitat selection dynamics within populations. At a finer temporal resolution and using individual-based modelling, I have collaborated with Drs. S. Railsback and B. Harvey to understand what drives circadian variation in the activity and habitat selection behaviour of stream salmonids (Railsback et al. 2020, under review).
Territoriality is probably the most important ecological mechanism regulating stream-living salmonid populations, and thus territory size is often regarded as the proximate factor that limits population abundance. While body size is often considered the best predictor of territory size, other ecological factors such as food availability and competitor density can affect the allometry of territory size. Therefore, we have conducted in silico simulation experiments (Ayllón et al. 2010) as well as empirical experiments in a hatchery (Nicola et al. 2016) to disentangle the role of these three factors on brown trout territorial and foraging behaviour.
Daniel Ayllón 