Spatial patterns of caddisflies from Austral South America

DOS SANTOS, DANIEL ANDRÉS; RUEDA MARTÍN, PAOLA; REYNAGA, MARÍA CELINA

SYSTEMATICS AND BIODIVERSITY

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2015 vol. 13 p. 419 - 433

1477-2000

Trichoptera are relevant members of the freshwater benthos that can exploit a broad variety of habitats. We explored their distribution patterns in Austral South America using a network quantitative approach applied on point occurrence data. The primary goal was to recognize groups of species connected by strong links of sympatry and secondarily to evaluate the structure of the sympatry network (patterns of connectivity) at higher taxonomic levels. We compiled 2,522 geographical points associated with 446 species. The strength of sympatry links were inferred directly from dot maps. Using the taxonomic resolution of species, we identified two major groups of co-occurring species that mimic in a geographic context the classic zoogeographical division of the study area: the Andean-Patagonian complex (of ?cold-adapted? organisms) versus the ExtraAndean domain (of ?warm-adapted? organisms) spanning the subtropical belt of the region. Within these major divisions, groups of highly co-distributed species were also found which in turn show a variety of overlapping spatial configurations. Overlap was centered at the following pivoting areas: Yungas of NW Argentina, Paranaense forest of NE Argentina and Valdivian temperate forest of Patagonia. Three very interesting findings emerged from the analyses: (i) Sierras Centrales of Córdoba correspond to the southern portion of many subtropical elements occurring in NW Argentina, (ii) some elements fit the disjunction between NW and NE Argentina and (iii) Uruguay is more closely related to NE Argentina than to Buenos Aires, suggesting that the Pampas region (Uruguay + Buenos Aires) could be an ill-defined biogeographical entity. Patterns at the species level become progressively blurred in going upward through the hierarchical classification.