Early recruitment responses to interactions between frequent fires, nutrients, and herbivory in the southern Amazon

14 de fevereiro de 2015

fev 14, 2015

Tara Joy Massad, Jennifer K. Balch, Cândida Lahís Mews, Pábio Porto, Ben Hur Marimon Junior, Raimundo Mota Quintino, Paulo M. Brando, Simone A. Vieira, Susan E. Trumbore

Understanding tropical forest diversity is a long-standing challenge in ecology. With global change, it has become increasingly important to understand how anthropogenic and natural factors interact to determine diversity.

Anthropogenic increases in fire frequency are among the global change variables affecting forest diversity and functioning, and seasonally dry forest of the southern Amazon is among the ecosystems most affected by such pressures. Studying how fire will impact forests in this region is therefore important for understanding ecosystem functioning and for designing effective conservation action.

We report the results of an experiment in which we manipulated fire, nutrient availability, and herbivory. We measured the effects of these interacting factors on the regenerative capacity of the ecotone between humid Amazon forest and Brazilian savanna. Regeneration density, diversity, and community composition were severely altered by fire. Additions of P and N + P reduced losses of density and richness in the first year post-fire. Herbivory was most important just after germination.

Diversity was positively correlated with herbivory in unburned forest, likely because fire reduced the number of reproductive individuals. This contrasts with earlier results from the same study system in which herbivory was related to increased diversity after fire. We documented a significant effect of fire frequency; diversity in triennially burned forest was more similar to that in unburned than in annually burned forest, and the community composition of triennially burned forest was intermediate between unburned and annually burned areas. Preventing frequent fires will therefore help reduce losses in diversity in the southern Amazon’s matrix of human-altered landscapes.

Baixar (sujeito à disponibilidade)

Download (subject to availability)

Veja também

See also

The role of forest conversion, degradation, and disturbance in the carbon dynamics of Amazon indigenous territories and protected areas

The role of forest conversion, degradation, and disturbance in the carbon dynamics of Amazon indigenous territories and protected areas

Significance For decades, Amazon indigenous peoples and local communities (IPLCs) have impeded deforestation and associated greenhouse gas emissions. While emissions inside indigenous territories (ITs) and protected natural areas (PNAs) remain well below levels...