Victoria Crozier |
Plasticité phénotypique des caractéristiques de reproduction chez les mouflons d’Amérique en réponse au changement climatique. Comme le changement climatique modifie les conditions environnementales, les espèces doivent être capable de s'adapter afin de persister. L’un des mécanismes biologiques permettant de s'adapter à un environnement changeant est la plasticité phénotypique. Cependant, la plasticité n'est pas toujours adaptative. Chez les mouflons d'Amérique (Ovis canadensis), il a récemment été découvert qu’ils ont modifié le moment où ils mettent bas en réponse à un changement des conditions environnementales à l'automne. En effet, ils donnent naissance une quinzaine de jour plus tôt (en 25 ans) au printemps. Cependant, les conditions printanières n'ont pas changé sur cette période. Les femelles donne donc naissance dans des conditions printanières plus défavorables. Une parturition précoce mène donc à une inadéquation entre la phénologie de la reproduction et les conditions environnementales printanières optimales, qui peut augmenter le coût de la reproduction en diminuant initialement les réserves maternelles dans une plus large mesure, ce qui pourrait potentiellement diminuer leur fitness. L'objectif de mon projet est d'abord d'évaluer si le gain de masse des mères est affecté lorsque la naissance de leur agneau est décalée par rapport aux conditions printanières. J’évaluerai ensuite s’il y a des conséquences sur la survie des femelles à l'hiver et la probabilité de mettre bas l'année suivante. |
Phenotypic plasticity of reproductive traits in bighorn ewes in response to climate change
As climate change alters environmental conditions, species must be able to adapt in order to persist. One such way to adapt to a changing environment is phenotypic plasticity, which allows for a faster response to a rapidly changing environment than does evolution. However, plasticity is not always adaptive. It has been recently found that bighorn sheep (Ovis canadensis) have altered the timing in which they give birth in response to a change in environmental conditions in the fall, giving birth an average of fifteen days earlier in the spring than 25 years ago. However, spring conditions have not changed to the same extent. Bighorn ewes greatly increase their energy expenditure while lactating, and partially compensate by increasing food uptake. Earlier parturition creates a mismatch between reproductive phenology and optimal environmental spring conditions. My project aims to evaluate whether mother mass gain is impacted when the birth of their lamb is mistimed with spring conditions, and if so, whether there is a consequence on their fitness measure by the female survival in the following winter and the probability of giving birth in the next year.
As climate change alters environmental conditions, species must be able to adapt in order to persist. One such way to adapt to a changing environment is phenotypic plasticity, which allows for a faster response to a rapidly changing environment than does evolution. However, plasticity is not always adaptive. It has been recently found that bighorn sheep (Ovis canadensis) have altered the timing in which they give birth in response to a change in environmental conditions in the fall, giving birth an average of fifteen days earlier in the spring than 25 years ago. However, spring conditions have not changed to the same extent. Bighorn ewes greatly increase their energy expenditure while lactating, and partially compensate by increasing food uptake. Earlier parturition creates a mismatch between reproductive phenology and optimal environmental spring conditions. My project aims to evaluate whether mother mass gain is impacted when the birth of their lamb is mistimed with spring conditions, and if so, whether there is a consequence on their fitness measure by the female survival in the following winter and the probability of giving birth in the next year.