What allows a population in a heterogeneous landscape to become locally adapted? In general, adaptation to a rare habitat type is difficult because divergent selection is counter-acted by the homogenising effects of gene-flow. However adaptation to a rare habitat type may occur if it has a higher quality, so that a greater number of offspring can be produced there, to compensate for its relative rarity … Continue reading Carryover effects and local adaptation
Collaborators: Kenneth Schmidt, Jacob Johansson, François Massol, Niclas Jonzen. Breeding birds subject to nest-predation will attempt to choose a high quality nesting site with a low density of predators. For example, when recordings of chipmunk calls are played in the forest, ovenbirds will nest away from where the recordings are playing (Eureka Alert). Often models assume perfect information, so that sites are filled from highest … Continue reading Ecology of information
Here’s a nice video I stumbled upon about Lisa Aubry’s group’s work at Utah State Uni. Climate change is having a positive effect on uinta ground squirrels, allowing them to fatten-up and attain weights higher than those recorded historically. This population is survival limited, and survival probability is higher the fatter the squirrels are, so abundance responds positively to this climate change. I can’t handle … Continue reading Bad for birds, good for squirrels
A lightning talk for our latest paper: Kristensen, Nadiah P., Jacob Johansson, Jörgen Ripa, and Niclas Jonzén. 2015. “Phenology of two interdependent traits in migratory birds in response to climate change.” Proceedings of the Royal Society B Continue reading Lightning talk on migratory bird phenology
Environmental fluctuations may cause natural selection to favor phenologies that systematically deviate from the resource maximizing strategy. In temporally variable environments, because fitness is taken from the geometric (not arithmetic) mean growth rate (Gillespie, 1974), this permits the evolution of bet-hedging strategies (Simons, 2011), which are strategies that maximises total fitness by reducing temporal variation at the cost of arithmetic mean fitness (Ripa et al. … Continue reading On phenology and bet-hedging
[Update: Four years after this blog post, I published a paper in Ecology Letters that was partly inspired by this system: Carryover effects from natal habitat type upon competitive ability lead to trait divergence or source–sink dynamics] I’ve recently been reading about a several decade long study centred around blue tits in France and on the island of Corsica. The work is being carried out … Continue reading The interesting case of blue tits in France
Typically the the kinds of models that I’m interested in assume that fledging rate is very dependent upon a phenological match between nestlings’ peak food requirements and the peak in caterpillar abundance. However I recently read a study by Cholewa and Wesołowski (2011; Acta Ornithologica) pointing out that, while literature shows that blue tits and marsh tits are indeed strongly dependent upon this food type, … Continue reading Are caterpillars really that important?
Climate change has caused an advance in phenological events in many species. In migratory birds, the effects of warming flow causally up the trophic levels. For example, warmer temperatures lead to earlier plant phenology (e.g. budding), which leads to earlier peaks in the abundance of foods (e.g. insect larva) that are important to raising nestlings, which puts pressure upon birds to advance their own breeding … Continue reading Do birds sometimes respond to warming temperatures by delaying their phenology?
Food availability at the breeding site often has a peaked temporal profile such that food is very abundant for a short period of time. Therefore, migratory birds must also time their arrival such that there is adequate time to gather the resources needed for egg production, and time their nesting and laying so that nestlings can take advantage of these food peaks. Failure to do … Continue reading What is the relationship between lay date, mismatch, and overall fitness for migratory birds?
Climate change has caused an advance in phenological events in many species (Forchhammer et al. 1998, Chmielewski & Rotzer 2001, Parmesan & Yohe 2003, Edwards & Richardson 2004, Menzel et al. 2006, Beebee 2009). In migratory birds, the effects of warming flow causally up the trophic levels. For example, warmer temperatures lead to earlier plant phenology (e.g. budding) (Menzel et al. 2006, Schwartz et al. … Continue reading The problem of arrival time and prelaying period in migratory birds