Dados do Trabalho


Título

FOREST FRAGMENTATION AND DEFAUNATION DRIVE AN UNUSUAL ECOLOGICAL CASCADE: PREDATION RELEASE, MONKEY POPULATION OUTBURST AND PLANT DEMOGRAPHIC COLLAPSE

Resumo

<p>Anthropogenic habitat fragmentation combined with differential defaunation triggers complex trophic cascades. Here we test a Fragmentation-Defaunation Cascade Hypothesis by examining how a small-monkey population (<em>Sapajus nigritus</em>) burst resulting from predation-free fragmentation leads to the decline of a dominant plant (<em>Euterpe edulis</em>). We computed long-term population dynamics of <em>Euterpe edulis</em> (“palmito”) plants in a Brazilian Atlantic Forest landscape, where the palmito predator, capuchin monkey, becomes hyper-abundant in fragments. Palmito plants (N=1193) were marked and measured to define stage (height and diameter) categories in 2005, and annually censused (2006-2015) in a 3,500-ha fragment. Newly recruited plants within plots were marked and monitored throughout the 10-year period. Lefkovitch matrices for each transition year, population growth rate (ʎ), elasticity, and plant stage distribution showed a strong trend of palmito demographic decline, due to monkey lethal consumption of palm hearts. Indeed, ʎ calculations revealed that, by the end of study period, palmito was decreasing by 31%, 39% and 32% annually. Also, a major shift in plant stage distribution occurred within the population which, increasingly, became proportionally dominated by infants, while reproductives continuously declined (zero reproductive plants recruitment), suggesting that palmito will soon become extinct in predator-defaunated fragments. We conclude that, in the absence of predators, forest fragments undergo differential defaunation, with small mammal outbursts (e.g., small monkey “primatization”) negatively impacting the demography of previously dominant host plant populations. We posit that Anthropogenic fragmentation-selective defaunation synergies disrupt animal communities with cascading effects trickling down to plant demographic collapse and, potentially, forest community structure.</p>

Financiamento

FAPESP, CNPQ, CAPES

Palavras-chave

monkey-plant interaction; “primatization”; Sapajus nigritus

Área

Área 1 - Ecologia

Autores

Rita de Cássia Quitete Portela, Rodolfo Dirzo