Changes of dung beetle communities from rainforests towards agroforestry systems and annual cultures in Sulawesi (Indonesia)

Abstract

Little is known about how tropical land-use systems contribute to the conservation of functionally important insect groups, including dung beetles. In a study at the margin of Lore Lindu National Park (a biodiversity hotspot in Central Sulawesi, Indonesia) dung-beetle communities were sampled in natural forest, young secondary forest, agroforestry systems (cacao plantations with shade trees) and annual cultures (maize fields), each with four replicates (n ¼ 16 sites). At each site we used 10 pitfall traps, baited with cattle dung, along a 100 m transect for six 3-day periods. The number of trapped specimens and species richness at the natural forest sites was higher than in all land-use systems, which did not significantly differ. Each land-use system contained, on average, 75% of the species richness of the natural forest, thereby indicating their importance for conservation. However, a two-dimensional scaling plot based on NESS indices (m ¼ 6) indicated distinct dung beetle communities for both forest types, while agroforestry systems and annual cultures exhibited a pronounced overlap. Mean body size of dung beetles was not significantly influenced by land-use intensity. Five of the six most abundant dung beetle species were recorded in all habitats, whereas the abundance of five other species was significantly related to habitat type. Mean local abundance and number of occupied sites were closely correlated, further indicating little habitat specialisation. The low dung beetle diversity (total of 18 recorded species) may be due to the absence of larger mammals in Sulawesi during historical times, even though Sulawesi is the largest island of Wallacea. In conclusion, the dung beetle fauna of the lower montane forest zone in Central Sulawesi appears to be relatively robust to man-made habitat changes and the majority of species did not exhibit strong habitat preferences.

Hymenoptera (Insecta: Hymenoptera) associated with silvopastoral systems

“…1), which is considered high when compared with the data obtained by D'avila and Marchini (2008), who determined H 0 = 1.69 when surveying the cerrado biome, indicating that the environment studied provided favorable conditions for the development of pollinators, possibly due to the presence of species rich in flower production. Our data agree with that of Shahabuddin et al (2005) and Ricketts et al (2008), who cited the high biodiversity in agricultural landscapes as an important tool for pollinator maintenance.…”

Abandonement of coffee agroforests increases insect abundance and diversity

“…Weibull and Ö stmann (2003) showed that habitat type and surrounding landscape had a greater influence on the arthropod community than did management of the ecosystem. In contrast, Shahabuddin et al (2005) did not find differences between dung beetle communities in agroforests and young secondary forests (5-6 years old), however species richness of agroforests was lower. Perfecto et al (2003) found great differences between taxa in diversity responses to land-use activities.…”

Invasion and retreat: shifting assemblages of dung beetles amidst changing agricultural landscapes in central Peru

“…However, in Mexico (Estrada et al 1998;Arellano et al 2005) and Costa Rica (Harvey et al 2006), the species occurring in agroforestry systems were subsets of the original forest fauna (only one open-habitat species, Canthon eurycelis, occurred in small numbers in cacao in Mexico [Estrada et al 1998], and one, Pseudocanthon perplexus, in banana in Costa Rica). Davis et al (2001) and Shahabuddin and Tscharntke (2005) in Indonesia and Bornea, respectively, found low dung beetle species richness in plantations compared to intact forest. In Indonesia, assemblages in cacao plantations were similar to those of both young secondary forest and annual crops and included a mix of forest and open-habitat species (Shahabuddin and Tscharntke 2005).…”