Effect of sun exposure on saproxylic beetle assemblages may change with topoclimate in a subtropical forest of east China

Abstract

Sun exposure is an important determinant of diversity and distribution of saproxylic beetles. However, the sun requirement of saproxylic beetles in forests outside of Europe is still poorly known. In this study, we explored the effect of sun exposure on the biodiversity of saproxylic beetles in a subtropical forest of east China. Beetles were sampled from 64 newly cut boles of Pinus taiwanensis and Cryptomeria fortunei which were equally distributed across high-exposed and low-exposed sites on a warm southfacing and a cold north-facing slope (94 replicates) during 2 years by, respectively, using flight intercept and emergence traps. It was suggested that sun exposure had no significant effect on species richness of saproxylic beetles. Its effect on beetle abundance changed over the season and significantly varied with topoclimate in the colder months of April and May. Species richness and abundance of beetles associated with different trees did not respond differently to sun exposure. Significantly more beetle individuals were trapped on the warm south-facing slope than on the cold north-facing slope, but aspect had no detectable effect on beetle species richness. Beetle assemblages were significantly affected by sun exposure, but tended to be more similar among low-exposed sites across different slopes. In general, our results indicated that sun exposure is not a sufficient indicator of species richness of saproxylic beetles, but may play an important role in retaining the integrity of saproxylic fauna in subtropical forests. The effect of sun exposure on biodiversity of saproxylic beetles is affected by topoclimate variations.

The role of nature reserves in preserving saproxylic biodiversity: using longhorn beetles (Coleoptera: Cerambycidae) as bioindicators

“…Thus, it is important to explore their habitat requirements (Horák et al 2011) and mechanisms driving their occurrence. Studies on the relationships between saproxylic beetles and deadwood have been undertaken relatively recently (Speight 1989;Martikainen et al 2000;Grove 2002;Lachat et al 2007Lachat et al , 2012Lachat et al , 2016Dollin et al 2008;Müller & Bütler 2010;Lassauce et al 2011;Boucher et al 2012;Hjältén et al 2012;Wu et al 2013Wu et al , 2015Müller et al 2014;De Zan et al 2014;Della Rocca et al 2014;Buse et al 2016;Heikkala et al 2016;Seibold et al 2016;Doerfler et al 2018;Jaworski et al 2019). Most of these studies were conducted in the temperate and boreal zones, while only a few refer to subtropical and tropical ones (Seibold et al 2015).…”

Edge effects on insect–plant food webs: assessing the influence of geographical orientation and microclimatic conditions

“…Even fewer studies, mostly focused on plant species, have considered the effects of microclimatic conditions in edges with different geographical orientation (Burton, 2002;Tomimatsu & Ohara, 2004;Hylander, 2005;Porensky, 2011;Eldegard et al, 2015). Changes in microclimatic conditions associated with geographical orientation have been studied mainly in relation to mountain slopes, with reported effects on various vegetation aspects (Auslander et al, 2003;Ortiz-Pulido & Pavón, 2010), as well as on development time, density, and activity of insect species (Auslander et al, 2003;Pen-Mouratov et al, 2009;Wu et al, 2015).…”