Odonata from Austral Yungas pedemontane forest: diversity patterns in a naturalproductive ecotone

DANIELA GÓMEZ, JOSÉ S. RODRÍGUEZ & CARLOS MOLINERI

La Plata

Congreso; INTERNATIONAL CONGRESS OF ODONATOLOGY; 2015

Pedemontane forest in the Yungas from NW Argentina is severely affected by human activities. Only small relict areas of natural vegetation remain, since most was converted to crops (sugar cane and citrus). Riparian forests (RF) may be continuous with the main forest (in protected areas), or impoverished in diversity/structure to totally absent in the productive areas. We studied adult Odonate diversity in these two situations in six localities (three with well preserved RF, and three withdamaged RF) from Jujuy and Salta provinces. We made at least three transects per site/date of 30 minutes each, counting every individual visible at sight or using binoculars in a 20 m wide strip.Individuals were identified to species using a regional key, some of them were captured to confirmidentification under magnification. The six sites were sampled four times, in dry and wet seasons 2013and 2014 (N=77 transects). RF conservation status was studied from ten vegetation transects per site (forest structure) and satellite images of the area (continuity and width of the RF). We recorded 45 species (1,112 individuals): 30 Anisoptera spp. (487 ind.) and 15 Zygoptera spp. (625 ind.).Accumulation curves (CHAO2) indicated a good sampling effort, with the following observed percentage of diversity: Zygoptera in damaged RF= 81%, well preserved RF= 89%; Anisoptera in damaged RF= 66%, well preserved RF= 79%. In the three sites representing damaged RF we found 13 Zygopteran spp. (395 ind.) and 27 Anisopteran spp. (266 ind.); in well preserved RF 7 species of Zygoptera (230 ind.) and 19 Anisopteran spp. (227 ind.) were present. Only one species (Hetaerinarosea, Calopteryigidae) showed a higher abundance in well preserved forest (T test, p= 0.04). We attribute the higher richness and abundance in the damaged sites to the presence of human-made pools at the margin of the rivers, that increased habitat heterogeneity.