Limnophora: Habitat

Michelsen, Verner, 2021, Macaronesian Muscidae (Diptera). II. The genus Limnophora Robineau-Desvoidy with description of a new Canarian endemic species, Zootaxa 4952 (1), pp. 101-127 : 126

Macaronesian Limnophora: Habitat requirements and threats

Most species of Macaronesian Limnophora have aquatic larvae and most of them may be strongly dependent on habitats of streaming water for larval development. Own field observations in the western Canary Islands suggest that the following species are wholly dependent on the availability of unpolluted lotic waters for larval development: L. beckeri , L. bipunctata , L. flavitarsis , L. nitidithorax and L. riparia . Bodies of stagnant water such as open tanks for water storage may be accepted by some species, e.g. L. obsignatula and L. paneliusi . In La Gomera I found L. quaterna in large numbers in an old orchard where larval development probably took place in heaps of rotten fruit and vegetables. Habitat requirements are unknown for the Afrotropical and Oriental L. exigua found in the Cape Verde Islands.

As documented by Malmqvist et al. (1995), Nilsson et al. (1998), Crosskey & Báez (2004) and others, the many permanent natural streams that earlier characterized the western Canarian islands of Gran Canaria, Tenerife, La Gomera and La Palma have diminished radically, because most fresh water is now captured by damming high in the mountains and conveyed down in closed pipes in order to satisfy the needs of agriculture, urbanization and tourism. The magnitude of eradication of natural water courses in the islands is evident from Lüderitz et al. (2016) who stated that the number of permanent streams in Gran Canaria has decreased from 285 in 1933 to 20 in 1973, and they found only two(!) moderately intact streams in 2009. A similar detour in undisturbed streams may as well have taken place in Tenerife, La Gomera and La Palma. As a consequence the invertebrate limnofauna of the Canary Islands is highly endangered. In respect to Limnophora , several species may face local or global extinction in a foreseeable future, unless targeted precautions are taken to protect and restore what is left of the perennial streams.