Macrophytes promote aquatic insect conservation in artificial ponds

Abstract

Farmland ponds promote regional aquatic biodiversity; however, optimally managing these ponds requires knowledge on how the biodiversity differs between ponds across catchments with different land uses. This study investigated the response of macrophytes, both those in the pond and on the bank, as well as dragonfly and water beetle species richness, diversity and composition in artificial ponds, to numerous environmental variables in catchments dominated by three land uses: protected areas (as reference sites), sugarcane‐dominated and forestry‐dominated landscapes, across two seasons. There was a strong association between insect species richness and vegetation cover, particularly sedges (Cyperus spp.) in spring and bulrushes (Typha capensis) in summer. There was also a positive response between insect species richness and sedges up to 70% cover, and bulrushes up to 40% cover, after which there was a decrease. Furthermore, the protected area ponds contained more rare and specialist insect species. Pond size was not a major variable for biodiversity overall. Although there was generally little congruence in composition among the three taxa, dragonflies were a good surrogate for water beetles and floating macrophytes. Well‐vegetated ponds, both in the water and along the margin, are the most suited to promoting biodiversity, as long as the vegetation is not too dense, and not dominated by one plant species. Artificial ponds in production landscapes have great potential for conserving aquatic species, irrespective of land use, as long as there is management for macrophyte density and heterogeneity.

Descriptions of the larvae of Acanthagrion speculum and A. trilobatum from Costa Rica (Odonata: Coenagrionidae)

“…Although it was not statistically analyzed, we found greater abundance and richness in sites where the diversity of aquatic plants was greater. This agrees with other studies where the positive relationship between aquatic plants and the abundance and richness of organisms was demonstrated (McKinney 2008, Silva et al 2010, Goertzen & Suhling 2013, Jeanmougin et al 2014, Dutra & De Marco 2015, Oliveira-Junior et al 2015, Vilela et al 2016, Villalobos-Jiménez et al 2016, Cuevas-Yáñez et al 2017, Briggs et al 2019.…”

Dragonfly (Odonata) Diversity Patterns in Mixohaline Coastal Wetlands

“…On a local scale, habitat features seem to have a primary role in shaping dragonfly assemblages (Remsburg and Turner 2009;Hart et al 2014). In particular, floating macrophytes determined the formation of dragonfly species assemblages (Schindler et al 2003) and macrophytes cover was significantly associated with dragonfly assemblage composition especially in spring and in summer (Briggs et al 2019). In addition, it has been proven that odonata larvae are influenced by vegetation structure in both aquatic and riparian habitats (Remsburg and Turner 2009).…”

Community assembly of adult odonates in lacustrine systems of an understudied world heritage site of south-eastern Zimbabwe

“…Considering threats to Odonata around lentic habitats in Matopos National Park we found natural system modifications to be the most significant threats. The likely modifications in MNP are likely related to hydroperiods (water level fluctuations) of dams that are affected by rainfall patterns in Southern Africa, as documented by other researchers (sensu Deacon, Samways, & Pryke, 2018;Briggs et al 2019;Jooste, Samways, & Deacon, 2020). According to IUCN (2020), the 'natural system modifications' is a threat category which covers a wide range of activities that convert or degrade habitats largely as a result of human management.…”