Montorio Lucie, Evanno Guillaume, Nevoux Marie
ESE, Ecology and Ecosystem Health, Agrocampus Ouest, INRA, 35042, Rennes, France.
INRA, 0985 (UMR ESE), Pôle GEST'AQUA, 35042, Rennes, France.
Oecologia. 2018 Oct;188(2):451-464. doi: 10.1007/s00442-018-4213-4. Epub 2018 Jul 6.
Population dynamics can be regulated through intra- and interspecific density dependence. In species with close ecological requirements, interspecific competition for resources may add to intraspecific density, or even exceed its effect; it may impact single or multiple traits. However, the relative impact of intra- and interspecific densities on demographic parameters has been rarely empirically assessed. We analyzed 18 years of capture-mark-recapture data from brown trout (Salmo trutta) coexisting with Atlantic salmon (Salmo salar) during the juvenile freshwater phase in the Oir River (France) to estimate the relative effects of intra- and interspecific density on trout early life. In trout, a species with optional migration, we estimated the migration probability of young-of-the-year trout out of their natal site, survival probability during the first winter, as well as body size, in relation to both intra- and interspecific density. Trout density correlated negatively with body size and with winter survival in resident trout but not with trout migration. Salmon density correlated positively with trout migration, but no impact was detected on trout body size or survival. Our study highlighted contrasting effects of intra- and interspecific density on trout early life, and the need to account for both factors when studying population dynamics in coexisting species. In particular, by affecting trout migration decision, salmon density may drive trout life history.
种群动态可以通过种内和种间密度依赖来调节。在生态需求相近的物种中，种间对资源的竞争可能会增加种内密度，甚至超过其影响；它可能会影响单个或多个性状。然而，种内和种间密度对种群统计学参数的相对影响很少得到实证评估。我们分析了法国瓦尔河幼年淡水阶段与大西洋鲑（Salmo salar）共存的褐鳟（Salmo trutta）18年的标记重捕数据，以估计种内和种间密度对鳟鱼早期生活的相对影响。在鳟鱼这种具有选择性洄游的物种中，我们估计了当年幼鱼离开出生地的洄游概率、第一个冬季的存活概率以及与种内和种间密度相关的体型大小。鳟鱼密度与常驻鳟鱼的体型大小和冬季存活率呈负相关，但与鳟鱼洄游无关。鲑鱼密度与鳟鱼洄游呈正相关，但对鳟鱼体型大小或存活率没有影响。我们的研究强调了种内和种间密度对鳟鱼早期生活的不同影响，以及在研究共存物种的种群动态时需要考虑这两个因素。特别是，通过影响鳟鱼的洄游决策，鲑鱼密度可能会驱动鳟鱼的生活史。
