COMPETITION BETWEEN NATIVE BROWN TROUT AND NON-NATIVE BROOK TROUT
The introduction of brook trout (top) in European streams has been shown to affect the diet, behavior, and fitness of native brown trout (bottom). Interestingly, when occurring in sympatry, brown trout adopts a diet similar to that of brook charr, which goes against the classical hypothesis of competitive exclusion. Using stream enclosures, I try to investigate if this diet shift may result from temporal competition between the two species, and/or from other mechanisms. This work is being carried out with the Salmonid Ecology Group at Gothenburg University. |
Photo credit: Joacim Näslund
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ECOLOGICAL DETERMINANTS OF DIEL ACTIVITY
Juvenile salmonids exhibit exceptionally flexible diel activity patterns. This variability results in part from the variable conditions they experience. During my Ph.D., I tried to better identify the effect of several ecological variables (water temperature, current velocity, depth, shelter availability etc.) on how young Arctic charr (Salvelinus alpinus) distribute their foraging effort over the 24 h cycle in stream enclosures. I also monitored other aspects of their behavior (foraging mode, mobility, aggregation) around the clock. This work was supervised by Dr. Stefán Óli Steingrímsson at Hólar University College (Iceland). |
BEHAVIORAL SYNDROMES
Studies have suggested that different individuals show consistent differences in behavior over time and across situations and that different aspects of behavior can be correlated. Although this has important ecological and evolutionary implications, those behavioral syndromes have rarely been studied under natural conditions. I studied different aspects of Arctic charr's behavior in stream enclosures, including space use (habitat use, home range) and foraging mode (mobility while searching for prey, foraging radius, location of foraging attempts in the water column). I also explore if differences among individuals may affect fitness (growth, exposure to predators). |
MOBILITY AND MATING BEHAVIOR
Mobility is an important determinant of fitness through e.g. life expectancy, which should affect reproductive decisions of animals. During my masters, I monitored the copulations of Large White butterflies (Pieris brassicae) to see how mobility affected mating patterns (like assortative matings) and the timing of copulations (latency and duration). I did this project, along with other experiments, under the supervision of Dr Delphine Legrand and Dr Michel Baguette at the Station d'Ecologie Théorique et Experimentale (Moulis, France). |
SPATIAL DISTRIBUTION OF MOBILITY PHENOTYPES
Where an organism lives and moves affects its encounters with potential mates. This has strong implications for species with high within-population variability in mobility, because within their distribution areas, mobile and sedentary individuals are not randomly distributed. I use individual-based models to investigate the effect of phenotype distribution, variability in mobility, and habitat heterogeneity on encounter rates and the occurrence of assortative mating. |