Biology subjects

Rebello Landim, A.

Publications and source records attributed to Rebello Landim, A..

2 recordsLinked to original sources

bioRxiv2021

The reintroduction of a dung-beetle associated primate increases the recruitment success of large seeds

The biased loss of large and medium frugivores alters seed dispersal and plant regeneration. Species reintroductions have been proposed as a strategy to reverse the consequences of species loss. However, the effects of reintroductions on ecological processes are seldom accessed, which hinders the comprehension of reintroductions potential to reestablish functioning ecosystems. In this study, we investigate the effect of howler monkey (Alouatta guariba) reintroduction on the plant regeneration of Tijuca National Park (TNP), a defaunated Atlantic Forest fragment. Howlers are folivore-frugivore primates, whose large clumped defecations attract dung beetles, which provide secondary dispersal by burying seeds present in the howlers feces. Thus, we expect that the fate of seeds dispersed by howlers will differ from those dispersed by other frugivores present in the Park. We followed the fate of seeds between 3 and 14mm in diameter in three steps of the seed dispersal loop, each one consisting of a different experiment. First, we estimated secondary seed dispersal and burial depth probabilities according to the frugivores defecation pattern; then, predation probability in different burial depths and defecation patterns; and, finally, recruitment probability in different burial depths. Considering the final result of the three experiments, the howlers reintroduction affected positively the regeneration of large seeds. The fate of 3mm seeds was little affected because they were seldom preyed upon at shallower depths anyway and could not recruit when deeply buried. On the other hand, seeds larger than 3mm reached the seedling stage more frequently when dispersed by howlers than when dispersed by other animals present in the Park. Thus, howler monkey reintroduction in defaunated areas, in addition to smaller frugivores, whose defecation patterns are less attractive for dung beetles, improves the regeneration of large seeds. We hope that this study will stimulate new howler reintroductions in defaunated areas.

ecology↗

bioRxiv2020

A framework that highlights the effects of extinctions and colonizations on processes derived from trophic interactions

Functional diversity uses response and effect traits to understand how communities are affected by changes in the environment and their consequences on the structure and functioning of ecosystems. However, most studies focus on a single taxonomic or functional group, ignoring that many ecological processes result from trophic interactions. Here we established a multi-trophic trait-based framework to evaluate the consequences of community change for ecological processes resulting from trophic interactions. Specifically, we estimated the potential effect of each species considering the consumer and resource communities involved on the trophic interaction. The functional space of consumer and resource communities were incorporated into a single analysis by using resource traits to estimate consumers functional space. Our framework included a parameter that establishes different weights to unique interactions when estimating a species potential effect. We presented two modifications for application using abundance and species richness data and two modifications to allow incorporating absent species into the analysis. Our framework can be used to investigate consequences of community changes in different situations, such as species extinctions, invasions and refaunation. To demonstrate the insights derived from our framework we used an exemplary study case of refaunation of an impacted tropical forest. Our framework informs on a species contribution to an ecological process according to its originality, i.e., the uniqueness or redundancy of its interactions, and the magnitude of the effect, indicated by the frequency of the resources community trait values with which it interacts. Thus, it helps to increase the understanding of the effects of changes in community composition on ecological processes resulting from trophic interactions. It assists practitioners and researches with predictions and evaluations on potential loss and reestablishment of ecological functions resulted from changes in community functional composition.

ecology↗