Plasticité squelettogénique chez une espèce d'amphibien en milieux anthropisés

Résumé

Habitat loss and landscape fragmentation are major causes of numerous amphibian population declines. Although logging activities have been related to serious effects on growth rate and size at metamorphosis in several species, less is known about skeletal developmental modifications associated with disturbed habitats. We studied the effects of forest canopy modifications caused by logging activities on the skeletal development of a pond-breeding anuran, Wood Frog (Lithobates sylvaticus). Biotic and abiotic factors were collected for 30 semi-permanent ponds located in three habitat categories (regenerated forest, along skidding trails, and logged areas). A sample of 58 cleared and double-stained tadpoles were analyzed to compare developmental trajectories among habitats. Water temperature and pond morphometric characteristics, which were correlated with logging-related habitat alteration, had a major impact on tadpole developmental differences among pond categories. Developmental plasticity was evident in both absolute and relative timing of chondrification and ossification between regenerated forest ponds and disturbed ponds (i.e., along skidding trails and in logged areas). Ossification and chondrification patterns had a different response to environmental factors. Notably, we observed the early onset of skeletogenesis in the disturbed ponds, which may result in deleterious effects on the fitness of post-metamorphosed juveniles.