Conservation Corridors With Many Small Waterbodies Support Dragonfly Functional Diversity Across a Transformed Landscape Mosaic

Abstract

Aim

Human activities pose many challenges to freshwater biodiversity. Among these, is landscape transformation, such as conversion of natural grassland to plantation forestry, impacting both terrestrial and freshwater biodiversity. Functional diversity measures provide substantial information on current and emerging impacts on biological communities, and aid conservation decisions relative to anthropogenic impacts. We determined (1) environmental similarities among 10 freshwater biotope types; (2) whether freshwater biotopes in conservation corridor networks support equal levels of functional richness and divergence compared with an extensive neighbouring protected area; (3) whether certain biotopes are more important for maintaining functional richness and divergence than others; and (4) whether associations between traits and biotope types could be identified.

Location

The northeastern coastal region of South Africa.

Methods

Using dragonflies as model organisms, and data from 140 freshwater lotic and lentic sites, we investigated the distribution of dragonfly traits across a plantation forestry-natural grassland landscape mosaic with a range of biotope types.

Results

Lake sites were different in their environmental conditions compared with the other biotopes. Environmental conditions were variable among the other biotope types and were difficult to distinguish. Freshwater biotopes in the conservation corridors supported equal levels of functional richness and divergence compared with those in the protected area. Overall, dragonfly functional richness and divergence were low at lake sites and wallows, while all other biotopes supported high levels of functional richness and divergence. Trait associations were complex across the waterscape and driven by habitat selection, flight behaviour and ecological sensitivity.

Main Conclusions

Maintaining a mosaic of small lentic and lotic habitats would best support dragonfly conservation in this transformed landscape. A combination of biotopes offers a wide range of environmental conditions essential for conserving the full range of dragonfly traits and species across the region.