Global diversity of dragonflies (Odonata) in freshwater

Abstract

Larvae of almost all of the 5,680 species of the insect order Odonata (dragonflies and damselflies) are dependent on freshwater habitats. Both larvae and adults are predators. The order is relatively well studied, and the actual number of species may be close to 7,000. Many species have small distributional ranges, and are habitat specialists, including inhabitants of alpine mountain bogs, seepage areas in tropical rain forests, and waterfalls. They are often successfully used as indicators for environmental health and conservation management. The highest diversity is found in flowing waters in rain forests of the tropics, the Oriental and Neotropical regions being the most speciose. This paper discusses diversity, summarises the biogeography of dragonflies in the different biogeographical regions and gives the total number of species and genera per family per biogeographical region. Examples are given of areas of particular diversity, in terms of areas of endemism, presence of ancient lineages or remarkable recent radiations but no well-based review of areas with high endemism of dragonflies is available so far. The conservation status of dragonflies is briefly discussed. Species confined to small remnants of forest in the tropics are most under threat of extinction by human activities.

Effect of Environmental Disturbances on Odonata Assemblages along a Tropical Polluted River

“…Many are strong fliers, and most of them prefer open and half-shaded area. According to Kalkman et al (2008), open landscapes are generally better for tropical species to colonise new habitats and these dragonflies seem to be less influenced by habitat modification. They can recolonise impacted areas in the presence of good growth of riparian vegetations.…”

Diversity of Odonata (Insecta) larvae in streams and farm ponds of a montane region in southern Brazil

“…one-third (9) of the families recorded for the entire Neotropics (21, Kalkman et al 2008) was found in the middle course of the Jacuí River. However, the pattern of their diversity in the Neotropical region (Kalkman et al 2008) was maintained.…”

“…one-third (9) of the families recorded for the entire Neotropics (21, Kalkman et al 2008) was found in the middle course of the Jacuí River. However, the pattern of their diversity in the Neotropical region (Kalkman et al 2008) was maintained. Libellulidae was represented by the most genera, followed by Coenagrionidae and Gomphidae, whereas Calopterygidae, Corduliidae, and Lestidae were represented by only one genus each.…”

“…However, the diversity of odonates is not well known in certain regions of the world. According to Kalkman et al (2008) 1,000 to 1,500 species are yet to be described. In Brazil, which occupies ca.…”

“…These conditions may allow the presence of a diversified odonatofauna (Kalkman et al 2008). In fact, some studies have suggested that in regions with temperate climate, certain groups of riverine macroinvertebrates may have greater richness than in regions with tropical climate (e.g., McKie et al 2005;see Floss et al 2012 for southern Brazil).…”