Abstract
BackgroundVast areas of lowland neotropical forest have regenerated after initially being cleared for agricultural purposes. The ecological value of regenerating second growth to forest-dwelling birds may largely depend on the age of the forest, associated vegetative structure, and when it is capable of sustaining avian demographics similar to those found in pristine forest.MethodsTo determine the influence of second growth age on bird demography, we estimated the annual survival of six central Amazonian bird species residing in pristine forest, a single 100 and a single 10 ha forest fragment, taking into consideration age of the surrounding matrix (i.e. regenerating forest adjacent to each fragment) as an explanatory variable.ResultsStudy species exhibited three responses: arboreal, flocking and ant-following insectivores (Willisornis poecilinotus, Thamnomanes ardesiacus and Pithys albifrons) showed declines in survival associated with fragmentation followed by an increase in survival after 5 years of matrix regeneration. Conversely, Percnostola rufifrons, a gap-specialist, showed elevated survival in response to fragmentation followed by a decline after 5 years of regeneration. Lastly, facultative flocking and frugivore species (Glyphorynchus spirurus and Dixiphia pipra, respectively) showed no response to adjacent clearing and subsequent regeneration.ConclusionsOur results in association with previous studies confirm that the value of regenerating forest surrounding habitat patches is dependent on two factors: ecological guild of the species in question and second growth age. Given the rapid increase in survival following succession, we suggest that the ecological value of young tropical forest should not be based solely on a contemporary snapshot, but rather, on the future value of mature second growth as well.
Highlights
Vast areas of lowland neotropical forest have regenerated after initially being cleared for agricultural purposes
At the Biological Dynamics of Forest Fragmentation Project (BDFFP) near Manaus, Brazil, the relationship between bird populations within fragments and the surrounding matrix was measured over a 30-year period, where the fragmentation of pristine forest led to a rapid increase in bird capture rates, indicative of higher abundance following isolation (Bierregaard and Lovejoy 1989)
The dynamic role of a developing matrix revealed at the BDFFP suggests that bird survival in fragments is likely mediated by the matrix as well
Summary
Vast areas of lowland neotropical forest have regenerated after initially being cleared for agricultural purposes. At the Biological Dynamics of Forest Fragmentation Project (BDFFP) near Manaus, Brazil, the relationship between bird populations within fragments and the surrounding matrix was measured over a 30-year period, where the fragmentation of pristine forest led to a rapid increase in bird capture rates, indicative of higher abundance following isolation (Bierregaard and Lovejoy 1989). After years of matrix regeneration, many of the previously absent species returned to the fragments (Stouffer et al 2011), and established themselves within adjacent second growth (Wolfe et al 2015) Once established, these pioneering bird populations in fragments and second growth may be subject to source-sink dynamics where vulnerable species periodically perish and are subsequently replaced by individuals from higher quality habitats with higher survival and reproductive surpluses (Sodhi et al 2011). Exploring critical links between the survival of tropical birds within forest fragments and the condition of the surrounding matrix should be an essential focus of conservation biology in tropical forests
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
