Designating conservation priorities for Southeast European hoverflies (Diptera: Syrphidae) based on species distribution models and species vulnerability

Abstract

Information on the distribution and vulnerability of invertebrates is often scarce and, as a consequence, this group of organisms is usually neglected in conservation studies. Yet it is possible to reasonably infer ranges and vulnerabilities of species and establish spatial conservation priorities, even with incomplete information. We investigated conservation priorities of hoverflies in Southeast Europe based on species distribution models (SDM) and vulnerability indices. Species distribution models were used to compensate for the lack of knowledge on species ranges. Measures related to geographical rarity, endemism and habitat specialisation were used to assess species vulnerability. Potential distribution and three alternative vulnerability indices were used to calculate two spatial conservation indices: potential Biodiversity Conservation Concern index (pBCC) and potential Biodiversity Conservation Weight (pBCW). pBCC highlighted areas with a large proportion of highly vulnerable species, even where species richness was low, such as the Danube delta and mid‐Aegean islands. It also identified potentially important areas yet‐to‐be surveyed (e.g. Carpathian mountains), which might deserve future conservation measures. pBCW emphasised areas hosting high richness of both vulnerable and resilient species, such as the eastern Aegean Islands and the eastern part of Crete. We demonstrate that: (i) it is possible to establish conservation priorities at large scales if SDM and simple vulnerability measures are combined; (ii) complementary approaches are necessary to emphasise the importance of areas with different characteristics; and (iii) several understudied areas should be targets of future sampling schemes to confirm their importance for the conservation of hoverfly diversity in Southeast Europe.

Effects of climate change on the distribution of hoverfly species (Diptera: Syrphidae) in Southeast Europe

“…For reducing sampling bias, we applied the thinning procedure, where we used a threshold of 0.01 of the maximum distance between any two points. The procedure is explained in detail in Miličić et al (2017). After data processing, all species with less than five occurrence points were dropped (the number of occurrences per species is assessable in occurrence data table, provided on the link above in text).…”

“…First, we used all variables. Then, using only the stronger predictors for each species, we built the final models and, in that way, avoiding overfitting the models (see details in Miličić et al 2017).…”

Lessons from insect conservation in Russia

“…Several alternatives to the standard Red List categorisation following IUCN criteria were suggested and successfully applied in the past; combining various indices of species rarity, vulnerability or taxonomic distinctiveness (e.g. Kattan 1992;Freitag and van Jaarsveld 1997;Fattorini 2010Fattorini , 2011Fattorini , 2014Matenaar et al 2015;Miličić et al 2017). The Russian sozological analyses are generally based on similar principles (except for disregarding taxonomic distinctiveness), with the rare and more vulnerable species receiving higher scores and thus being assigned to higher categories of conservation concern.…”

New records and updated distribution of Myopa metallica Camras 1992 (Diptera: Conopidae: Myopinae) in Chile by using integrative collection methods

“…2c). With this information, it could be possible to combine some biotic or abiotic variables to know the most important environmental conditions or habitat requirements for M. metallica or even modelling the distribution by using scarce occurrence data (Miličić et al 2017). In conclusion, our work breaks down barriers between classic methods and existing technology to provide an updated distribution of an endemic, conspicuous and rare thick-headed fl y.…”