A large-scale approach can help detect general processes driving the dynamics of brown trout populations in extensive areas

作者：Alonso Carlos^*; Garcia de Jalon Diego; Alvarez Javier; Gortazar Javier

来源：Ecology of Freshwater Fish, 2011, 20(3): 449-460.

DOI：10.1111/j.1600-0633.2011.00484.x

• population dynamics
• brown trout
• North Atlantic Oscillation
• synchrony

Most studies on the population dynamics of stream-living salmonids have been conducted at the scale of a reach, a stream or a river basin. This can lead to overestimating the importance of local factors acting on a reduced scale compared to the more general factors that drive the dynamics of several populations. Two models were built on the basis of a data set from 60 sampling stations representing separated populations inhabiting a large heterogeneous area encompassing 18 years of quantifications. Our analyses showed the following: (i) Population growth rate (pgr) of a set of independent brown trout populations can be described by means of a single model; (ii) the youngest and the oldest year classes of these populations seem to be limited by the same constraints; (iii) there is a climatic control of the recruitment because of spring weather conditions, but also the abundance of oldest age class may be controlled by the climate, (iv) there is a nonlinear positive effect of winter North Atlantic Oscillation on pgr; (v) there is a 3-year lagged positive feedback tracing the upward trend of a stock-recruitment curve, and 1-year lagged negative feedback showing the downward trend of the curve; (vi) a strong cohort has a positive effect on the whole population that can be detected throughout the time. Our fitted models allowed to predict the mean population densities at a regional scale with < 10% error and shed light onto the main factors and associated ecological processes that control these large-scale dynamics.

• 出版日期2011-9