Affiliation:
1. Division of Biological Sciences University of Montana Missoula Montana USA
Abstract
AbstractA fundamental goal of ecology is to understand how the physical environment influences intraspecific variability in life history and, consequently, fitness. In streams, discharge and associated habitat conditions change along a continuum from intermittency to permanence: Headwater streams typically have smaller watersheds and are thus more prone to drying than higher‐order streams with larger watersheds and more consistent discharge. However, few empirical studies have assessed life history and associated population responses to this continuum in aquatic organisms. We tested the prediction that individual growth, rate of development, and population growth increase with watershed area in the long‐lived stream salamander Gyrinophilus porphyriticus, where we use watershed area as a proxy for hydrologic intermittence. To address this hypothesis, we used 8 years of mark–recapture data from 53 reaches across 10 headwater streams in New Hampshire, USA. Individual growth rates and mean size at metamorphosis increased with watershed area for watersheds from 0.12 to 1.66 km2. Population growth rates increased with watershed area; however, this result was not statistically significant at our sample size. Mean age of metamorphosis did not vary across watershed areas. Lower individual growth rates and smaller sizes at metamorphosis likely contributed to reduced lifetime fecundity and population growth in reaches with the smallest watershed areas and highest vulnerability to drought. These responses suggest that as droughts increase due to climate change, headwater specialists in hydrologically intermittent environments will experience a reduction in fitness due to smaller body sizes or other growth‐related mechanisms.
Funder
National Science Foundation
Subject
Ecology, Evolution, Behavior and Systematics
Reference46 articles.
1. Long‐term survival probability, not current habitat quality, predicts dispersal distance in a stream salamander
2. Adaptive Intrinsic Growth Rates: An Integration Across Taxa
3. Arias P. N.Bellouin E.Coppola R.Jones G.Krinner J.Marotzke V.Naik et al.2021.“Climate Change 2021: The Physical Science Basis.”Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change; Technical Summary.
4. How Metamorphosis Is Different in Plethodontids: Larval Life History Perspective on Life‐Cycle Evolution;Beachy C. K.;Herpetologica,2017
5. Body length shrinkage in an endangered amphibian is associated with drought