High variability of dung beetle diversity patterns at four mountains of the Trans-Mexican Volcanic Belt

Abstract

Insect diversity patterns of high mountain ecosystems remain poorly studied in the tropics. Sampling dung beetles of the subfamilies Aphodiinae, Scarabaeinae, and Geotrupinae was carried out at four volcanoes in the Trans-Mexican Volcanic Belt (TMVB) in the Mexican transition zone at 2,700 and 3,400 MASL, and on the windward and leeward sides. Sampling units represented a forest–shrubland–pasture (FSP) mosaic typical of this mountain region. A total of 3,430 individuals of 29 dung beetle species were collected. Diversity, abundance and compositional similarity (CS) displayed a high variability at all scales; elevation, cardinal direction, or FSP mosaics did not show any patterns of higher or lower values of those measures. The four mountains were different regarding dispersion patterns and taxonomic groups, both for species and individuals. Onthophagus chevrolati dominated all four mountains with an overall relative abundance of 63%. CS was not related to distance among mountains, but when O. chevrolati was excluded from the analysis, CS values based on species abundance decreased with increasing distance. Speciation, dispersion, and environmental instability are suggested as the main drivers of high mountain diversity patterns, acting together at different spatial and temporal scales. Three species new to science were collected (>10% of all species sampled). These discoveries may indicate that speciation rate is high among these volcanoes—a hypothesis that is also supported by the elevated number of collected species with a restricted montane distribution. Dispersion is an important factor in driving species composition, although naturally limited between high mountains; horizontal colonization events at different time scales may best explain the observed species composition in the TMVB, complemented by vertical colonization events to a lesser extent. Environmental instability may be the main factor causing the high variability of diversity and abundance patterns found during sampling. Together, we interpret these results as indicating that species richness and composition in the high mountains of the TMVB may be driven by biogeographical history while variability in diversity is determined by ecological factors. We argue that current conservation strategies do not focus sufficiently on protecting high mountain fauna, and that there is a need for developing and applying new conservation concepts that take into account the high spatial and temporal variability of this system.

Climate rather than dung resources predict dung beetle abundance and diversity along elevational and land use gradients on Mt. Kilimanjaro

“…In contrast, Aphodiinae dung beetles, consisting of dwellers, showed a hump‐shaped distribution of both abundance and species richness with elevation. This pattern mirrors trends along latitudinal gradients: The warm‐adapted Scarabaeinae dung beetles reach their highest species richness in tropical savannas (Hanksi & Cambefort, ) while cold‐adapted Aphodiine dwellers replace Scarabaeinae dung beetles in cold climates (Arriaga‐Jiménez, Rös, & Halffter, ), reaching their highest richness in temperate latitudes (Chamberlain et al, ; Martín Piera, Veiga, & Lobo, ). Turnover was mainly responsible for the changes in species composition with elevation while nestedness only played an inferior role.…”

Archipelago reserves, a new option to protect montane entomofauna and beta-diverse ecosystems

“…With this study, we can infer that temperate National Parks are not particularly efficient in terms of protecting the montane entomofauna in Mexico. This conclusion is based on the fact that National Parks are established in large areas (Arriaga-Jiménez et al, 2018; and protected areas in the eastern part of the Transmexican Volcanic Belt: a) orographic landscape features highlighting some of the highest mountains, b) regional land use. Unprotected mountains and native vegetation could be utilized to establish a system of interconnected islands in an Archipelago Reserve for the study area.…”

“…Our study reveals that beta diversity patterns and complementarity among sites in a mountain system could represent a first step to detect a suitable region to establish an Archipelago Reserve. Nevertheless, future spatial analysis that match beta diversity patterns and current protected area coverage, are required in order establish the best spatial configuration for future Archipelago Reserve (Arriaga-Jiménez et al, 2018).…”

“…In this article, we suggest a protection model taking as a study case some mountains of the eastern TMVB and the southern Sierra Madre Oriental. We reanalyzed the information generated in this mountain area using dung beetles as a focal group in previous biodiversity research ( Arriaga-Jiménez et al, 2018;. Therefore, a series of questions developed: How are the diversity patterns of insect communities in these mountain systems?…”

The integration processes of the distributional patterns in the Mexican Transition Zone: Phyletic, paleogeographic and ecological factors of a case study

“…Several species have an aggressive distribution, certainly recent. Arriaga-Jiménez et al (2018), studying the coprophagous beetles (Aphodinae, Geotrupinae, Scarabaeinae) of four mountains at the eastern end of the TMVB and that is in contact with the Sierra Madre Oriental, suggest that only "O. chevrolati chevrolati Harold" was found on all the mountains. Nevertheless, they mistakenly considered O. chevrolati, O. retusus Harold and O. orizabensis as the same species.…”