Trait‐modulated decline of carabid beetle occurrence along elevational gradients across the European Alps

Abstract

Aim: To assess how species traits modulate the responses of carabids to elevational gradients, and how consistent these relationships are across different Alpine regions.Location: Italian Alps. Taxon: Coleoptera, Carabidae (ground beetles).Methods: Carabid communities were sampled using pitfall traps along elevational gradients (697-2,840 m) in 416 study sites comprising a range of habitat types. The probability of carabid occurrence was modelled in relation to elevation and its interaction with two key traits, body size and wing development, using a mixed-modelling framework. The consistency of these associations was then assessed across three geographically separated regions. Results:Carabid occurrence declined with increasing elevation, although this relationship was modulated by both body size and wing development. Smaller species were less likely to occur than larger-bodied species at lower elevations. There was a steep decline in occurrence of larger species from low to high elevation, but a slight increase in smaller species, when considering all regions combined. All wing development types declined with elevation, most notably for brachypterous (reduced wings) species. However, these patterns also varied regionally, especially for wing development, indicating that trait-elevation interactions are not geographically consistent.Habitat could not explain the differences between regions for body size, but was likely an important driver of regional differences in the role of wing development on carabid occurrence. Main conclusions:Species traits are important in explaining the distribution of carabids along elevational gradients in mountains, and they may help to identify the species that are the most vulnerable, and the most resilient, to future environmental change. Increased probability of occurrence of smaller species at higher elevations suggests that they may be particularly vulnerable to environmental change in the future. However, the difference in responses to elevation between regions has important implications for modelling species distributions, as it suggests low model transferability, that is, a trait-based model derived from one region cannot necessarily be used to project relative elevational shifts in a wider area. | 1031 CHAMBERLAIN Et AL.

Distributional Patterns of Aquatic Empididae (Diptera) along an Elevational Diversity Gradient in a Low Mountain Range: An Example from Central Europe

“…A pronounced reduction in the number of Hemerodromiinae individuals was found from 400–450 m up, and only 10 individuals were recorded above 750 m. A dramatic decline in the number of individuals with increasing altitude was also revealed for Clinocerinae. For both subfamilies, a distinct species-poor community was recorded at the highest elevation (>750 m), which also corresponds with numerous other studies focused on mountain insect fauna [ 18 , 20 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ] and usually can be explained by the most extreme environmental conditions observed on the tops of mountain massifs.…”

“…Our study on the distribution of Hemerodromiinae and Clinocerinae along an elevational gradient indicate the richness and abundance decreases with altitude which is rather typical in the elevational distribution of different insect groups including e.g., beetles [ 20 , 29 , 31 , 32 , 34 , 36 ], butterflies [ 25 , 33 , 35 ], moths [ 18 , 28 ], or ants [ 26 , 27 , 30 ]. Comparing the abundance of both subfamilies across eight elevational bands, a clear downwards trend with increasing altitude was apparent.…”

“…On the other hand, relatively little was published on this topic in the case of insects, even if this is the most diverse animal group. Most studies were focused on butterflies, moths, ants, and beetles [ 18 , 20 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. With respect to the flies, not many studies have been dedicated to the distributional patterns along the elevational gradient, which is usually explained by many difficulties occurring during field sampling [ 37 , 38 , 39 , 40 , 41 , 42 ].…”

“…With respect to the flies, not many studies have been dedicated to the distributional patterns along the elevational gradient, which is usually explained by many difficulties occurring during field sampling [ 37 , 38 , 39 , 40 , 41 , 42 ]. Moreover, significantly more data are available for terrestrial insects [ 32 , 34 , 35 , 36 ] than for the aquatic groups, especially flies [ 43 , 44 , 45 , 46 , 47 , 48 ]. In addition, most of the studies mentioned above were done in the high mountain habitats located in the tropical regions.…”

Six groups of ground-dwelling arthropods show different diversity responses along elevational gradients in the Swiss Alps

“…Furthermore, within the same taxonomical group, different patterns have been demonstrated on different mountain slopes (e.g. in ants [ 58 ] and in ground beetles [ 89 ]). In our study, we aimed to analyse general patterns for six different arthropod groups by combining data from four mountain slopes (transect lines).…”