Plant adaptive responses during primary succession are associated with functional adaptations in ground beetles on deglaciated terrain

Abstract

Little is known of how changes in plant function may influence adaptive traits amongst animals further up the food chain. We addressed the hypothesis that shifts in plant functional traits are associated with the adaptive function of animal species which have an indirect trophic link. We compared community characteristics and functional traits of two trophically detached biotic groups (vascular plants and carabid beetles) along a primary succession on terrain at the Cedec glacier in the Alps, where deglaciation events following post-Little Ice Age climate warmings are marked by moraine ridges. Morphofunctional traits were recorded: canopy height (CH), leaf dry matter content (LDMC), leaf dry weight (LDW) and specific leaf area (SLA) (for plants) and the number of brachypterous, autumn-breeding and predator species, and average body length (for carabid beetles). We found that vegetation cover and plant species richness gradually increased throughout early succession, with an abrupt increase between 40 and 150 years after deglaciation. At the early stages of the succession plant traits were typical of ruderal species (high SLA, low CH, LDW) whilst a shift in traits towards stress-tolerance (low SLA) occurred >150 years. Carabid communities and traits changed alongside changes in plant species richness and cover, with late successional vegetation hosting larger, more diverse, less mobile carabid species with longer larval development. Thus, ruderal plant strategies are the main contributors during vegetation development, determining vegetation quantity, and probably have the greatest impact on changes in carabid assemblages by regulating resource availability. Plants then require greater stress-tolerance to survive in stable vegetation, which supports high carabid diversity. This suggests that different plant strategies may affect ground beetle communities via contrasting mechanisms: both quantities (biomass, species richness) and qualities (functional traits, adaptive strategies) should be taken into account during studies of plant-animal interactions within ecosystems.

Plant and arthropod colonisation of a glacier foreland in a peripheral mountain range

“…Therefore, plant and arthropod species follow different colonisation patterns, even if species richness generally 20 increases for both along the succession. Our result contrast with those of Gobbi et al (2010), where plant and arthropod species richness vary in steps along the chronosequence. Our hypothesis (1) is thus not supported by our data.…”

“…Arthropod successions were also investigated, even though the studies are fewer and more recent (e.g. Gereben, Krenn, and Strodl 2011;Gobbi et al 2006aGobbi et al , 2010Kaufmann 2001Kaufmann , 45 2002Schlegel and Riesen 2012). However, almost all the previous works were performed on glacier forelands located in the inner massifs of the Alpine chain, while knowledge about peripheral mountain ranges is still poor due to the scarcity of glaciers.…”

Do carabids (Coleoptera: Carabidae) and chironomids (Diptera: Chironomidae) exhibit similar diversity and distributional patterns along a spatio-temporal gradient on a glacier foreland?

“…This result is in agreement with similar studies on other alpine glacier forelands and on different taxa (e.g., spiders), confirming that around one-hundred years since deglaciation significant changes in species assemblages composition occur (Brambilla and Gobbi, 2013;Gobbi et al, 2006b). This ecological threshold probably marks the boundary between immature and mature habitats (Huggett, 2005;Gobbi et al, 2010). On the contrary, we did not observe a spatially structured distribution of chironomid species, meaning distance from the glacier front did not affect the species distribution within 1.3 km of stream.…”

To fly or not to fly: Factors influencing the flight capacity of carabid beetles (Coleoptera: Carabidae)

“…Nilsson (1993), however, whilst looking for an explanation for the low proportion of brachypterous species in montane regions of Scandinavia, did not consider the possibility of a latitudinal gradient. It has also been reported that the carabid fauna of dry meadow habitats in Finland (Venn et al, 2013) contains surprisingly few brachypterous species when compared to assemblages of similar habitats in central Europe (Gobbi et al, 2010). An explanation of this trend is that the regional carabid fauna of dry meadows includes only three brachypterous species, so there is no possibility of their comprising a substantial element of the fauna of those habitats in Finland (Venn et al, 2013).…”