Land use, fallow period and the recovery of a Caatinga forest

Abstract

Caatinga vegetation continues to be converted into mosaics of secondary forest stands, but the affect of this process on biodiversity has not yet been examined. We used 35 regenerating and old-growth stands of Caatinga to examine the recovery of plant assemblages subsequent to slash-and-burn agriculture and cattle ranching/pasture in northeastern Brazil. Plant assemblages were contrasted in terms of community structure (stem density/basal area/species richness/diversity), functional (leaf habit/reproductive traits) and taxonomic composition. Soil attributes were also examined to infer potential drivers for cross-habitat differences. As expected, plant assemblages clearly differed across a large set of community-level attributes, including all trait categories relative to leaf habit and reproduction (pollination syndrome/floral color, size, type). Overall, old-growth forest stands supported distinct and more diverse assemblages at the plot and habitat level; e.g., long-lived tree species were almost exclusively found in old-growth forest stands. For most attributes, plant assemblages subsequent to pasture exhibited intermediate values between those exhibited by old-growth forest and those of agriculture-related stands. Surprisingly, soils exhibited similar fertility-related scores across habitats. Our results indicate that: (1) sprouting/resprouting represents an important mechanism of forest regeneration; (2) assemblage-level attributes suggest recovery at distinct rates; (3) forest regeneration implies community-level changes in both vegetative and reproductive functional attributes, including directional changes; (4) Caatinga is not able to completely recover in a period of 15-yr following land abandonment; and (5) historical land use affects recovery rates and successional pathways/taxonomic trajectories. Seasonally dry tropical forests may intrinsically cover a wide range of patterns relative to successional model, recovery rates and successional pathways.Abstract in Portuguese is available with online material.

Functional organization of woody plant assemblages along precipitation and human disturbance gradients in a seasonally dry tropical forest

“…The Caatinga dry forest is the largest expanse of SDTFs in the Neotropics, with plant communities stretched over a variety of environmental gradients such as those caused by changes in precipitation (500 mm up to 1,000 mm of rainfall; da Silva et al, ). Moreover, slash‐and‐burn agriculture and the exploitation of forest products have converted most of the Caatinga old growth forest into a mosaic of forest patches exposed to varying levels of chronic disturbance (Ribeiro et al, ; da Silva et al, ; Sobrinho et al, ). Recent studies in the Caatinga have documented the influence of CAD and changes in precipitation levels as drivers of plant community organization, including taxonomic (Ribeiro et al, ; Ribeiro‐Neto, Arnan, Tabarelli, & Leal, ; Rito, Arroyo‐Rodríguez, et al, ; Siqueira et al, ), phylogenetic (Ribeiro et al, ), and functional patterns (Ribeiro et al, ; Sfair et al, ).…”

“…The Caatinga dry forest is the largest expanse of SDTFs in the Neotropics, with plant communities stretched over a variety of environmental gradients such as those caused by changes in precipitation (500 mm up to 1,000 mm of rainfall; da Silva et al, 2017). Moreover, slash-and-burn agriculture and the exploitation of forest products have converted most of the Caatinga old growth forest into a mosaic of forest patches exposed to varying levels of chronic disturbance (Ribeiro et al, 2015;da Silva et al, 2017;Sobrinho et al, 2016).…”

Analysis of Fallow Farming Decision-Making Behavior of Farmers Based on Hawk-Dove Game Theory: The Case of Guizhou Province

“…R+E . To verify whether x * = 2R−E R+E is the stable point of the equation, R = 10 and E = 6 are inserted into both Equations (5) and (6) and yield x = 1, x * = 7 8 . As shown in Figure 2, when the x-direction is shifted above the horizontal level of x * , the evolutionary stability strategy requires dF(x * ) dx < 0.…”

“…As shown in Figure 2, when the x-direction is shifted above the horizontal level of x * , the evolutionary stability strategy requires dF(x * ) dx < 0. When inserting R = 10, E = 6, x * = 7 8 into the equation to obtain F(x) < 0, it can be seen that x * = 2R−E R+E meets all the conditions of the evolutionarily stable strategy (ESS).…”

“…Implementing a farmland fallow system is significant for ensuring food security and sustainable use of resources. The land fallow in developed countries was mostly aimed at regulating grain production, and then gradually evolved into an important means to mitigate overproduction and improve the agricultural environment [6][7][8][9]. Europe, the United States, and Japan have been implementing cultivated land fallow since the 1930s, and relatively mature arable land fallow systems have been established [10][11][12], such as the Conservation Reserve Program (CRP), which was implemented in 1985 by the United States Department of Agriculture [13][14][15].…”