Are the Neotropical Swamp Forests a Distinguishable Forest Type? Patterns From Southeast and Southern Brazil

Abstract

This work synthesises information about plant diversity of 37 sites of coastal and inland swamp forests of southeast and southern Brazil and investigates floristic similarities and differences among them. Swamp forests often show low species richness, diversity and evenness, which are associated with the selective character of oxygen deprivation caused by soil waterlogging. However, our results pointed out some degree of site-level variation (Sobs = 5 to 110; Sjack1 = 6 to 151; H′ = 0.82 to 3.98; J′ = 0.51 to 0.87) related to local ecological conditions. Two major phytogeographical patterns emerged from our work: the strong influence of the neighbouring non-flooded vegetation on the flora of swamp forests and its high spatial heterogeneity. At least 85.9% of the 518 species sampled are found in neighbouring non-flooded vegetation. A correspondence analysis consistently separated swamp forests of the coastal plain from those of the plateau. A Mantel test indicated a significant correlation between floristic and geographical distances among sites (r = 0.45; p = 0.001), and highlighted the main effect of regional-scale changes in the flora of swamp forests. We conclude that swamp forests of southeast and southern Brazil cannot be considered a distinguishable floristic unit.

Dissecting a biodiversity hotspot: The importance of environmentally marginal habitats in the Atlantic Forest Domain of South America

“…forests into poorly drained soils of the Cerrado Domain showed only a weak differentiation from their neighbouring semideciduous forests (see Figure 3). Kurtz, Valentin, and Scarano (2015) also found that riv- Figure 3a). This is consistent with previous studies showing that forest-savanna boundaries in tropical savannas are driven by fire, though generally in interaction with other factors (Archibald et al, 2013;Dantas, Batalha, & Pausas, 2013;Hoffmann et al, 2012).…”

“…When assessing whether soil waterlogging leads to a floristically distinct marginal habitat, we found that the intrusions of riverine forests into poorly drained soils of the Cerrado Domain showed only a weak differentiation from their neighbouring semideciduous forests (see Figure ). Kurtz, Valentin, and Scarano () also found that riverine habitats of the Atlantic Domain are indistinguishable as a floristic unit from non‐flooded habitats, and that their flora is essentially an extract of the regional species pool. These trends may result from a particular feature of the Atlantic Domain.…”

Heterogenization of remaining biodiversity in fragmented tropical forests across agricultural landscapes

“…Despite the fact that these forests are influenced and determined by soil, altitude and climatic conditions (Oliveira-Filho & Fontes 2000), their floristic composition are strongly influenced by the surrounding vegetation ( e.g. SSF), creating complex transitional mosaics and continuum distribution of species (Kurtz et al 2015; Oliveira-Filho & Fontes 2000).…”

Diversity and Structure of Natural Regeneration in Swamp Forests in Southeastern Brazil

“…Plant diversity in each of the six study areas (H' varied from 1.82 to 3.18) was relatively low in relation to the high diversity commonly observed in tropical forests, as swamp forest formations are flooded for most of the year and show low diversity because of those anoxic conditions (Kurtz et al, 2013). Additionally, flooding durations and depths will influence swamp forest compositions (Parolin et al, 2010), as water stress selects for tolerant species that can form large populations, with low resulting diversity (Kurtz et al, 2015).…”