Abstract
Approximately 20% of the Brazilian Amazon has now been deforested, and the Amazon is currently experiencing the highest rates of deforestation in a decade, leading to large‐scale land‐use changes. Roads have consistently been implicated as drivers of ongoing Amazon deforestation and may act as corridors to facilitate species invasions. Long‐term data, however, are necessary to determine how ecological succession alters avian communities following deforestation and whether established roads lead to a constant influx of new species.We used data across nearly 40 years from a large‐scale deforestation experiment in the central Amazon to examine the avian colonization process in a spatial and temporal framework, considering the role that roads may play in facilitating colonization.Since 1979, 139 species that are not part of the original forest avifauna have been recorded, including more secondary forest species than expected based on the regional species pool. Among the 35 species considered to have colonized and become established, a disproportionate number were secondary forest birds (63%), almost all of which first appeared during the 1980s. These new residents comprise about 13% of the current community of permanent residents.Widespread generalists associated with secondary forest colonized quickly following deforestation, with few new species added after the first decade, despite a stable road connection. Few species associated with riverine forest or specialized habitats colonized, despite road connection to their preferred source habitat. Colonizing species remained restricted to anthropogenic habitats and did not infiltrate old‐growth forests nor displace forest birds.Deforestation and expansion of road networks into terra firme rainforest will continue to create degraded anthropogenic habitat. Even so, the initial pulse of colonization by nonprimary forest bird species was not the beginning of a protracted series of invasions in this study, and the process appears to be reversible by forest succession.
Highlights
Deforestation rates in the Amazon increased dramatically in the early 1970s, rose during the late 1990s to the highest absolute rates in the world, and accelerated once again during the early 2000s, before diminishing to the lowest rates in three decades (2012: Fearnside, 2005; INPE, 2019; Laurance, Albernaz, & Da Costa, 2001; Laurance, Cochrane, et al, 2001)
Widespread generalists associated with secondary forest colonized quickly fol‐ lowing deforestation, with few new species added after the first decade, despite a stable road connection
20% of the Brazilian Amazon has been defor‐ ested (Artaxo, 2019), including what amounts to a region of defor‐ estation larger than the state of California since 1988 (INPE, 2019)
Summary
Deforestation rates in the Amazon increased dramatically in the early 1970s, rose during the late 1990s to the highest absolute rates in the world, and accelerated once again during the early 2000s, before diminishing to the lowest rates in three decades (2012: Fearnside, 2005; INPE, 2019; Laurance, Albernaz, & Da Costa, 2001; Laurance, Cochrane, et al, 2001). Roads have consistently been implicated as direct and indirect drivers of Amazon deforestation (Barber, Cochrane, Souza, & Laurance, 2014; Barni, Fearnside, & Graca, 2015; Fearnside, 2015; Fearnside & Graca, 2006; Laurance, Albernaz, et al, 2001; Laurance et al, 2002; Nepstad et al, 2001; Soares‐Filho et al, 2006). We (a) use the regional spe‐ cies pool to identify possible colonists to the BDFFP and estimate the expected proportion of arrivals by habitat type, (b) describe the chronosequence and source habitat of all birds added to the core avifauna (sensu Cohn‐Haft et al, 1997), (c) plot the location and hab‐ itat of all first detections since 1995, and (d) assess the contribu‐ tion of landscape change, both locally and along two road corridors, to the process of colonization. We predict that new arrivals at the BDFFP are disproportionately represented by species from separate early‐successional habitats (e.g., second‐growth and riverine vegeta‐ tion) and that these additions reflect changes in regional access via roads and not local landscape changes
Sign-in/Register to view highlights & summary 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.
