Ecological and historical filters constraining spatial caddisfly distribution in Mediterranean rivers

Abstract

SUMMARY1. Contemporary species distributions are determined by a mixture of ecological and historical filters acting on several spatial and temporal scales. Mediterranean climate areas are one of the world's biodiversity hotspots with a high level of endemicity, which is linked to complex ecological and historical factors. 2. This paper explores the ecological and historical factors constraining the distribution of caddisfly species on a large regional scale. A total of 69 taxa were collected from 140 sampling sites in 10 Iberian Mediterranean river basins. Approximately 74% of taxa can be considered rare, with the southern basins (the Baetic-Riffian region) having greater endemicity. The greatest richness, involving a mixture of northern and southern species, was found in the transitional area between the Baetic-Riffian region and the Hesperic Massif. 3. The historical processes occurring during the Tertiary (i.e. the junction of the Eurasian and African plates) explained 3.1% of species distribution, whereas ecological factors accounted for 20.7%. Only 0.3% was explained by the interaction of history and ecology. A set of multi-scale ecological variables (i.e. basin, reach and bedform characteristics) defined five river types with specific caddisfly assemblages. The commonest caddisfly species accounted for the regional distribution pattern, while rare taxa contributed to the explanation of subtle patterns not shown by common species. 4. Despite the importance of historical factors for biogeography and the large scale used in our study, ecological variables better explained caddisfly distribution. This may be explained by the length of time since the historical process we are considering, the high dispersion and colonisation capacity of many caddisfly species, and the strong environmental gradient in the area. Because of the historical and environmental complexity of Mediterranean areas, rare taxa should be included in ecological studies so that the singularity of these ecosystems is not missed.

Crunoecia irrorata (Curtis) (Trichoptera: Lepidostomatidae) and conservation of boreal springs: indications of clustering of red‐listed species

“…temporal changes in climate, barriers limiting dispersal) influence species' distributions and often explain a considerable amount of assemblage variation on large geographical scales (e.g. Lillehammer, 1985;Va¨isa¨nen et al, 1992;Solem and Birks, 2000;Heino, 2001;Heino et al, 2002;Bonada et al, 2005). However, on a smaller scale, freshwater assemblages are usually more affected by local habitat characteristics than by large-scale geographical phenomena (Heino et al, 2002;Bonada et al, 2005).…”

“…Lillehammer, 1985;Va¨isa¨nen et al, 1992;Solem and Birks, 2000;Heino, 2001;Heino et al, 2002;Bonada et al, 2005). However, on a smaller scale, freshwater assemblages are usually more affected by local habitat characteristics than by large-scale geographical phenomena (Heino et al, 2002;Bonada et al, 2005). Besides large-scale and local-scale factors, species' distributions are also constrained by their dispersal ability, which therefore influences freshwater biotic assemblages (Hoffsten, 2004).…”

Large-scale macroinvertebrate assemblage patterns from least-disturbed wadeable stream sites across the 48 contiguous US states

“…European Union studies, while somewhat smaller in scale, were the only studies near the same scale (∼4 500 000 km 2 ), but coverage in these was less evenly spread across the study area Verdonschot, 2006b). Because perceptions about which environmental factors are most strongly related to assemblage composition depend in part on the spatial extent of observation (Marchant et al, 1999;Sandin and Johnson, 2004;Bonada et al, 2005;Johnson et al, 2007), we expected that we might find some consistencies and some differences between results of our study and those of other large-scale or national studies from elsewhere in the world. With ordinations based on invertebrates being identified to the finest practical level, we and others (Marchant et al, 1999;Turak et al, 1999;Heino et al, 2003;Lorenz et al, 2004;Sandin and Johnson, 2004) found a prominent relationship between invertebrate assemblage composition and geographic position (e.g.…”

“…Data collected for biological monitoring and assessment of rivers and streams have also been useful to increase our understanding of the natural interacting local, landscape, and regional environmental factors influencing invertebrate assemblage composition. As the spatial extent of sample and data collection expanded, it was noted that perceptions of which environmental factors are most strongly related to assemblage composition depend in part on the spatial extent of observation (Marchant et al, 1999;Sandin and Johnson, 2004;Bonada et al, 2005;Johnson et al, 2007). However, understanding the major factors relating to assemblage composition at a broad scale can give context to our understanding of factors controlling assemblages at smaller scales of observation.…”

On the Iberian endemism Eurylophella iberica Keffermuller and Da Terra 1978 (Ephemeroptera, Ephemerellidae): current and future potential distributions, and assessment of the effectiveness of the Natura 2000 network on its protection

“…However, the lithological composition of the substratum influences the conductivity and pH of aquatic systems and may affect the distribution patterns of aquatic species (e.g., Bonada et al 2005;Neff and Jackson 2011). Therefore, the percentage of each grid cell with an acidic surface geology (i.e.…”