Climate, invasive species and land use drive population dynamics of a cold-water specialist

Climate change is an additional stressor in a complex suite of threats facing freshwater biodiversity, particularly for cold-water fishes. Research addressing the consequences of climate change on cold-water fish has generally focused on temperature limits defining spatial distributions, largely ignoring how climatic variation influences population dynamics in the context of other existing stressors. We used long-term data from 92 populations of bull trout Salvelinus confluentus – one of North America's most cold-adapted fishes – to quantify additive and interactive effects of climate, invasive species and land use on population dynamics (abundance, variability and growth rate). Populations were generally depressed, more variable and declining where spawning and rearing stream habitat was limited, invasive species and land use were prevalent and stream temperatures were highest. Increasing stream temperature acted additively and independently, whereas land use and invasive species had...气候变化是淡水生物多样性所面临的一系列复杂威胁中的额外压力源，对冷水性鱼类的影响尤为显著。以往围绕气候变化对冷水鱼类影响展开的研究，大多聚焦于温度限值对其空间分布的界定，却在很大程度上忽略了在其他现存压力因子的背景下，气候变异如何影响种群动态。 本研究采用来自92个公牛鳟（Salvelinus confluentus，北美适应性最强的冷水性鱼类之一）种群的长期数据，量化了气候、入侵物种与土地利用对种群动态（种群丰度、波动幅度与增长率）的加性效应与交互效应。 当产卵与育幼溪流生境受限、入侵物种与土地利用压力普遍存在且溪流水温最高时，种群普遍出现丰度降低、波动加剧且呈衰退趋势。溪流水温升高表现出独立的加性效应，而土地利用与入侵物种则具有……