Short- and long-term population dynamical consequences of asymmetric climate change in black grouse

Abstract

Temporal asymmetry in patterns of regional climate change may jeopardize the match between the proximate and ultimate cues of the timing of breeding. The consequences on short-and long-term population dynamics and trends as well as the underlying mechanisms are, however, often unknown. Using long-term data from Finland, we demonstrate that black grouse (Tetrao tetrix) have responded to spring warming by advancing both egg-laying and hatching. However, early summer (the time of hatching) has not advanced, and chicks have to face colder post-hatching conditions. Demonstrating that these conditions are critical to post-hatching survival, we show that chicks are increasingly suffering higher mortality because they hatch too early. Consequently, breeding success and population size has severely declined over the past four decades. Finally, we modelled the impact of this particular climate change scenario on population dynamics and show that the mismatch can further explain the observed collapse of cyclic fluctuations. Because the evolutionary response of grouse is lagging behind the novel selective pressures, seasonally asymmetric climate change is likely to constitute an important determinant of future short-and long-term changes in the dynamics of black grouse populations.

Differences in spawning date between populations of common frog reveal local adaptation

“…Strong selection pressures may lead to population declines unless evolution can keep pace with the rate of environmental change (24,29) or efforts to reverse habitat fragmentation and increase landscape permeability are sufficient to increase the frequency of long-distance dispersal.…”

Earlier breeding, lower success: does the spatial scale of climatic conditions matter in a migratory passerine bird?

“…Such a climatic mismatch is comparable to previous findings in Finnish black grouse ( Tetrao tetrix ), where spring, but not summer temperatures, had increased, leading to earlier breeding but increased chick mortality due to hatching when climatic conditions were suboptimal (Ludwig et al. 2006). …”

Large-Scale Landscape Composition and Capercaillie (Tetrao urogallus) Density in Finland

“…These factors include noise (uncontrolled variation in habitat classification and capercaillie density), climatic conditions (variation in winter survival and breeding success) (e.g. Ludwig et al 2006) as well as hunting and predation pressure (geographical variation in predator assemblages) (Helle & Helle 1991, Storch 2000, Kauhala & Helle 2002 among others. On the other hand, the large size and the regular shape guarantee the approximate randomness of the wildlife triangles (Lindén et al 1996), and as there was on average, a high number of counted transect in each grid cell (> 1000 km in all regions), capercaillie densities within the grid cells are most probably representative.…”