Please use this identifier to cite or link to this item:
https://repositorio.inpa.gov.br/handle/1/18207
Title: | Disentangling the drivers of reduced long-distance seed dispersal by birds in an experimentally fragmented landscape |
Authors: | Uríarte, Ma?ia Anciães, Marina Silva, Mariana T.B. da Rubim, Paulo Johnson, Erik I. Bruna, Emilio M. |
Keywords: | Abundance Biological Invasion Biotic Factor Bird Frugivory Fruiting Habitat Fragmentation Herb Patch Size Population Dynamics Radio Telemetry Rainforest Seed Dispersal Songbird Understory Vertical Movement Animals Biological Model Bird Demography Fruit Heliconiaceae Physiology Seed Plant Time Tree Animal Birds Demography Fruit Heliconiaceae Models, Biological Seeds Time Factors Trees Amazonas Animalsia Aves Heliconia Heliconia Acuminata Turdus Turdus Albicollis |
Issue Date: | 2011 |
metadata.dc.publisher.journal: | Ecology |
metadata.dc.relation.ispartof: | Volume 92, Número 4, Pags. 924-937 |
Abstract: | Seed dispersal is a crucial component of plant population dynamics. Human landscape modifications, such as habitat destruction and fragmentation, can alter the abundance of fruiting plants and animal dispersers, foraging rates, vector movement, and the composition of the disperser community, all of which can singly or in concert affect seed dispersal. Here, we quantify and tease apart the effects of landscape configuration, namely, fragmentation of primary forest and the composition of the surrounding forest matrix, on individual components of seed dispersal of Heliconia acuminata, an Amazonian understory herb. First we identified the effects of landscape configuration on the abundance of fruiting plants and six bird disperser species. Although highly variable in space and time, densities of fruiting plants were similar in continuous forest and fragments. However, the two largestbodied avian dispersers were less common or absent in small fragments. Second, we determined whether fragmentation affected foraging rates. Fruit removal rates were similar and very high across the landscape, suggesting that Heliconia fruits are a key resource for small frugivores in this landscape. Third, we used radiotelemetry and statistical models to quantify how landscape configuration influences vector movement patterns. Bird dispersers flew farther and faster, and perched longer in primary relative to secondary forests. One species also altered its movement direction in response to habitat boundaries between primary and secondary forests. Finally, we parameterized a simulation model linking data on fruit density and disperser abundance and behavior with empirical estimates of seed retention times to generate seed dispersal patterns in two hypothetical landscapes. Despite clear changes in bird movement in response to landscape configuration, our simulations demonstrate that these differences had negligible effects on dispersal distances. However, small fragments had reduced densities of Turdus albicollis, the largest-bodied disperser and the only one to both regurgitate and defecate seeds. This change in Turdus abundance acted together with lower numbers of fruiting plants in small fragments to decrease the probability of long-distance dispersal events from small patches. These findings emphasize the importance of foraging style for seed dispersal and highlight the primacy of habitat size relative to spatial configuration in preserving biotic interactions. © 2011 by the Ecological Society of America. |
metadata.dc.identifier.doi: | 10.1890/10-0709.1 |
Appears in Collections: | Artigos |
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.