Flood regime and water table determines tree distribution in a forest-savanna gradient in the Brazilian Pantanal

Abstract

This study aimed to recognized the preferential location of species of the tree sinusiae in response to a moisture gradient in Pantanal Matogrossense, Brazil. We established sampling plots of arboreal sinusiae along a soil moisture and fl ood gradient. Piezometers were installed, allowing monthly measurements of water table depth and fl ood height during one year. Detrended Correspondence Analysis, Gradient Direct Analysis, Multi-response Permutation Procedures and Indicator Species Analysis were performed to evaluate the effect of moisture gradient on tree distribution. The annual variation of water table is shallower and similar in Seasonally Flooded Forest and Termite Savanna, with increasing depths in Open Savanna, Savanna Forest and Dry Forest. Circa 64% of the species were characterized as having a preferential location in "terrestrial habitats normally not subjected to inundation", while 8% preferentially occur in "wet habitats". Lowest tree richness in fl ood-affected vegetation types is related to both present-day high climatic seasonality and Late Pleistocene dry paleoclimates in the Pantanal wetland. The tree distribution across different formations in the Pantanal shows a direct relationship with soil moisture gradient.

Among‐species variation in flower size determines florivory in the largest tropical wetland

“…The Pantanal is the world's largest tropical wetland, presenting an intense environmental seasonality marked by dry and rainy seasons and a periodic flooding regime, temporal patterns that eventually determine plant species distribution, phenology, and trait selection in this ecosystem (Junk et al, 2006; Ferreira‐Júnior et al, 2016; Catian et al, 2019; Simão et al, 2021). The intensity and timing of rains and floods also create a diversity of permanently or temporarily flooded habitats, some with low flooding and others never flooded (forming an aquatic–semiaquatic–terrestrial continuum), which ultimately determine the dominance of aquatic or terrestrial plants (Adamoli, 1995; Junk et al, 2006; Scremin‐Dias et al, 2011).…”

Seasonality determines bird abundance, richness, and diversity among contrasting forest environments in the Northern Pantanal

“…The Pantanal is one of the world's largest seasonally flooded ecosystems (Junk et al 2006;Ferreira-Júnior et al 2016), harboring one of the highest bird richness (Tubelis and Tomas 2003). In Brazil, the Pantanal spans ca.…”

“…In Brazil, the Pantanal spans ca. 140,000 km 2 comprising different types of vegetation such as savannas, grasslands, and forests (Junk et al 1989;Ferreira-Júnior et al 2016). Each of those types of vegetation includes a diverse, season-dependent, range of environments differing in composition and structure of plant community (Junk et al 1989;Junk and Cunha 2009;da Costa et al 2010).…”