Beetle biodiversity in forest habitats in Laos depends on the level of human exploitation

Abstract

Coleopteran diversity was compared between more and less disturbed lowland evergreen deciduous forests located in Phou Phanang National protected area, Lao PDR. Using window traps and pitfall traps and collecting beetles from March until December 2018, a total of 6243 specimens were obtained. The number of morphospecies found in the less disturbed forest was significantly higher as compared to the more disturbed forest. Slightly more morphospecies were found in the window traps compared to pitfall traps and a significantly higher number of morphospecies were found in the wet season (June and September collections), compared to the dry season (March and December collections). Similarly, more than twice as many specimens were found in the less disturbed forest, compared to the more disturbed forest and also again more were found in the wet season, in particular predators. The data presented here indicate that so far largely undisturbed forests in Lao PDR need to be better protected from human exploitation such as logging.

Organic farming drives higher diversity of beetles, with more predators and less pests

“…The conversion of organic agriculture to conventional practices has been particularly evident in large-scale banana plantations (NAFRI, 2016); revealing a steady transition from subsistence agriculture to commercial production through the use of chemical fertilizers and pesticides. We previously demonstrated that the conversion of natural forests into plantations decreases beetle abundance and diversity (Chouangthavy and Fourcade 2023; Chouangthavy et al 2020), showing that agriculture expansion is an obstacle to the preservation of insect biodiversity in Laos. In response to concerns over suspected health risks for farm workers and consumers, as well as water contamination associated with the heavy use of agrochemicals on farms, the promotion of organic agriculture in Laos has been supported by rural development NGOs and private sector enterprises seeking access to premium markets.…”

Large‐scale sampling of beetle communities in Laos shows that conversion of natural forests into plantations leads to a decline in family richness and abundance

“…Until fairly recently, the insect fauna of Laos remained one of the most poorly known in Southeast Asia (Sekerka & Geiser, 2016 ) and existing knowledge mostly comes from specimens collected by foreign visitors before the 1920s. Recently, though, we observed an increase in the number of entomological expeditions, permitted by the country becoming more accessible to foreigners (Chouangthavy et al, 2020 ).…”

“…Indeed, infrastructure development will increase the general appeal of the region and encourage foreign investment, contributing to direct and indirect threats to local ecosystems (Borda‐de‐Água et al, 2017 ; Torres et al, 2016 ). Knowledge of the influence of human impact, through an effect on landscape structure, on insect diversity in southern Asia, and in Laos in particular, remains insufficient (but see e.g., Chouangthavy et al, 2020 ).…”

“…In southern Asia and in Laos in particular, despite the fact that beetle diversity is high (Moodley et al, 2022 ) and human activity is growing, the approach of employing beetle community composition, richness, and abundance as surrogates for estimating the impact of agricultural intensification and anthropogenic disturbance has been rarely carried out, especially in Laos. The few studies addressing the question of beetle community richness in relation to human factors were restricted to specific local contexts (Chouangthavy et al, 2020 ), and were insufficient to estimate more broadly the actual impact of human pressures on beetle biodiversity in Laos. There is thus a need for large‐scale assessments of beetle diversity conducted in natural versus anthropogenic landscapes, in order to estimate the effect of Laos' land use change on its rich biodiversity.…”