Tree species distribution in Andean forests: influence of regional and local factors

Abstract

Abstract:We identified and quantified regional and local environmental factors and spatial variation associated with tree-species composition across a 2000-m altitudinal gradient of Andean forest in north-western Argentina. A network of 47 1-ha plots was established along the altitudinal gradient within an area of about 25 000 km2; all trees ≥ 10 cm dbh were identified and measured. Constrained ordinations and variance-partitioning analyses were performed to investigate the determinants of tree-species distribution at the regional scale, across and within forest types (i.e. dry and cloud forests). We marked and measured a total of 22 240 trees belonging to 160 species. Significant environmental factors and spatial location combined accounted for 35% of total variation explained. A high proportion of variation was explained by climatic factors that were spatially structured; after removing the spatial effect, climate explained more variation in species composition across the complete gradient than did local factors. Relative importance of regional and local factors varied with geographic extent. Local factors explained more variation in tree-species composition at the within-forest scale than at the scale of the complete gradient. Our findings support the conceptual model of multi-scale controls on vegetation distribution, where local community composition and abundance result from processes at both regional and local scales.

The effect of anthropic pressures and elevation on the large and medium-sized terrestrial mammals of the subtropical mountain forests (Yungas) of NW Argentina

“…fraction of animal dispersed vs wind dispersed fruits) an abiotic (e.g. moisture stress) factors (Blundo et al, 2012;Malizia et al, unpublished results). In other tropical systems the diversity of mammals and the species composition of the mammal assemblage change along ecological gradients that vary is tree species composition and structural complexity (August, 1983;Williams et al, 2002;Tews et al, 2004) Thus, we expected to find the observed pattern of mean species richness per cameratrap station decreasing with elevation and the correlation between elevation and the NMDS ordination.…”

“…The abundance of both ungulates and top predators is usually higher in the better-protected areas and increases with the distance to the more accessible areas frequented by poachers (e.g., Caro, 1999;Di Bitetti et al, 2008, 2010. Livestock grazing is an activity that usually has notorious effects on the structure and composition of natural communities (Cingolani et al, 2008;Blundo et al, 2012). Among the mammals, large herbivores may be negatively affected by cattle through competitive interactions (Madhusudan, 2004;Hibert et al, 2010).…”

“…In the Yungas, tree species composition is mostly determined by elevation, with a secondary role for local effects such as presence of cattle (Blundo et al, 2012). Elevation in turn is highly correlated with other biotic (e.g.…”

Floristic Comparison Between Two Tree Communities Associated With Habitat Descriptor Variables

“…Nevertheless, altitudinal variations comprise a complex set of variables related to temperature, air humidity, water availability, wind exposure, in addition to soil depth and drainage classes HOMEIER et al, 2010;BLUNDO et al, 2012).…”

An optimal proportion of mixing broad‐leaved forest for enhancing the effective productivity of moso bamboo

“…2012), for example, through its influence on climate conditions such as temperature and precipitation (Blundo et al. 2012; Krömer et al. 2013; Li et al.…”