Woody population distribution and environmental heterogeneity in a Chaco forest, Argentina

Abstract

Abstract. In southern humid Chaco forests dominated by Schinopsis balansae, woody plants are clumped and species composition varies spatially over short distances. We examined how these spatial patterns are associated with local environmental heterogeneity for three size classes of woody individuals: adults, saplings, and seedlings. Our study was based on the detailed description of two forest plots (3200 m2 in total) in which we mapped all individuals of woody species, and delimited patches with different microrelief, soil moisture, and ground cover of terrestrial bromeliads. Our results showed that woody‐individual distribution is related to local environmental heterogeneity. For all size classes, density of woody individuals was highest on convex patches. These convex patches were dominated by both tree (Acacia praecox and Achatocarpus praecox) and shrub species (Celtis pallida, Capparis retusa and Grabowskia duplicata), while level patches were dominated only by tree species (Schinopsis balansae, Prosopis spp. and Geoffroea decorticans). Drier patches contained all the woody species present in the forest, while wetter patches contained only a subset of them. Within convex patches, trees are likely to occur in places with bromeliad colonies and shrubs in patches without bromeliads. The results suggest forest structure is controlled by environmental heterogeneity associated with microrelief and soil moisture.

Morphological variation of Aechmea distichantha (Bromeliaceae) in a Chaco forest: habitat and size‐related effects

“…The observed phenotypic plasticity in A. distichantha was probably favoured by the highly heterogeneous habitats of the S. balansae woodlands (Barberis et al. 2002; Barberis & Lewis 2005).…”

“…1997; Barberis & Lewis 2005). In these open forests, woody species distribution is related to local environmental heterogeneity (Barberis et al. 2002).…”

“…2002). There are patches of closed forest (about 10–12 m tall) in convex areas, which typically alternate with stretches of savanna‐type vegetation in plain areas ranging from tens to hundreds of meters in width (Barberis et al. 2002).…”

Reproductive traits and floral visitors of Aechmea distichantha plants growing in different habitats of a South American xerophytic forest

“…The study was carried out in a stand of Schinopsis balansae forest ('quebrachal'; Lewis et al 1997), located at "Las Gamas", Santa Fe, Argentina (Estación Experimental Tito Livio Coppa, 29 o 28'S, 60 o 28'W, 58 m above the sea level). This site at the Cuña Boscosa Santafesina is located at the southernmost range of the distribution of A. distichantha of the Eastern Chaco (Lewis 1991; Barberis et al 1998Barberis et al , 2002Barberis et al , 2014. The climate is humid temperate to warm, with a mean annual temperature of about 20 o C, and a mean annual precipitation of about 1,000 mm.…”

“…The forest is located on a mosaic of soils with low hydraulic conductivity, high sodium content and high electrical conductivity (Espino et al 1983). These forests show high environmental heterogeneity, mostly related to topographic variation, with high density of woody species on relatively elevated patches, and open areas with grassy vegetation (Barberis et al 2002). Aechmea distichantha plants are largely restricted to relatively elevated patches representing an important element of the understory, but may also grow at the edges of the open areas showing a gradient related to light exposure (Barberis et al 2014).…”