Value of artificial ponds for aquatic beetle and bug conservation in the Cape Floristic Region biodiversity hotspot

Abstract

ABSTRACT1. Freshwater insect species and their host ecosystems are widely threatened. This is particularly so within the agricultural and urban landscapes of Mediterranean-type ecosystems, including those of the Cape Floristic Region (CFR), South Africa. The value of 18 artificial ponds in the CFR was determined for aquatic beetle and bug abundance and species richness, a topic that has been little explored in Africa in general.2. In total, 17 814 aquatic beetle and bug individuals were sampled, from 94 taxa, representing 37 genera and 57 species. Bugs were much more abundant than beetles, representing 82% of all the individuals collected. The beetle and bug fauna showed high levels of endemism, with 36% restricted to the Western Cape Province.3. Five distinct groupings based on species abundances were identified, revealing overall high dissimilarities between groups, ranging from 65% to 82%.4. The associated physico-chemical characteristics of these sites were also investigated. The most important characteristics structuring pond communities were elevation, temperature, pH, pond size and flow regime. For bugs alone, the same variables, except elevation, were important. For beetles, only three variables were found to be most important in explaining community structure: elevation, pH, and flow regime.5. Artificial ponds in the CFR increase the area of occupancy of these insects, and therefore play a major role in conserving them.

Aquatic insects decline in abundance and occupy low‐quality artificial habitats to survive hydrological droughts

“…() sampled six endemic dragonflies (33% less than sampled here) from ponds in the same geographic area for 2014–2015, and Apinda‐Legnouo et al. () sampled eight endemic beetles (63% more) and one endemic bug (same number as sampled here) for 2014–2015.…”

“…Biological data were compared with pre‐drought studies, following the same sampling methods, in the same geographic area for dragonflies (Simaika et al., ; field data obtained 2014–2015), beetles and bugs (Apinda‐Legnouo et al., ; field data obtained 2005–2006). Although the sampling period of Simaika et al.…”

“…Aquatic insects make up much of total aquatic fauna (Batzer & Wissinger 1996) and fulfil several important biological and ecological roles. As such, aquatic insects can serve as indicators of environmental quality, and aid in understanding how droughts impact freshwater ecosystems (Apinda-Legnouo et al, 2014;Bird, 2010;Mlambo et al, 2011;Simaika, Samways, & Frenzel, 2016).…”

“…Elevation is an important driver of aquatic insect species richness and diversity in the region (Apinda-Legnouo et al, 2014;Samways & Niba, 2010). Lentic and lotic habitats at high elevations share some structural and physicochemical similarities, they provide a range of high-quality microhabitats and often have high species turnover (Biggs, Williams, Whitfield, Nicolet, & Weatherby, 2005).…”

Macrophytes promote aquatic insect conservation in artificial ponds

“…Farmland ponds are important habitats for many aquatic organisms, and contribute greatly to initiatives to enhance biodiversity (Céréghino, Ruggiero, Marty, & Angélibert, ; Williams et al, ). Ponds support heterogeneous communities of aquatic organisms, which often include rare species or those not found in other water bodies such as streams and rivers (Apinda‐Legnouo, Samways, & Simaika, ; Oertli et al, ; Pryke, Samways, & De Saedeleer, ; Simaika, Samways, & Frenzel, ; Williams et al, ). Yet farmland ponds are threatened by a range of impacts including chemical pollution, eutrophication from agricultural runoff, land‐use change, physical destruction and invasion by alien species (Curado, Hartel, & Arntzen, ; Declerck et al, ; Takamura, ).…”