title: Targeted reforestation could reverse declines in connectivity for understory birds in a tropical habitat corridor.
abstract: Re-establishing connectivity between protected areas isolated by habitat clearing is a key conservation goal in the humid tropics. In northeastern Costa Rica, payments for environmental services (PES) and a government ban on deforestation have subsidized forest protection and reforestation in the San Juan-La Selva Biological Corridor (SJLSBC), resulting in a decline in mature forest loss and the expansion of tree plantations. We use field studies and graph models to assess how conservation efforts have altered functional connectivity over the last 25 years for four species of insectivorous understory birds. Field playback studies assessed how reforestation habitat quality affected the willingness of Myrmeciza exsul, Henicorhina leucosticta, Thamnophilus atrinucha, and Glyphorynchus spirurus to travel outside forest habitat for territorial defense. Observed travel distances were greatest in nonnative and native tree plantations with high understory stem density, regardless of overstory composition. In contrast, tree plantations with low stem density had travel responses comparable to open pasture for three of the four bird species. We modeled landscape connectivity for each species using graph models based on varying possible travel distances in tree plantations, gallery forests, and pastures. From 1986 to 2011, connectivity for all species declined in the SJLSBC landscape (5825 km2) by 14% to 21% despite only a 4.9% net loss in forest area and the rapid expansion of tree plantations over 2% of the landscape. Plantation placement in the landscape limited their potential facilitation of connectivity because they were located either far from forest cover or within already contiguous forest areas. We mapped current connectivity bottlenecks and identified priority areas for future reforestation. We estimate that reforestation of priority areas could improve connectivity by 2% with only a 1% gain in forest cover, an impressive gain given the small area reforested. Results indicate key locations where spatial targeting of PES within the SJLSBC study region would protect existing forest connectivity and enhance the connectivity benefits of reforestation.
authors.affiliation: Biospheric Sciences, Goddard Space Flight Center, NASA, Greenbelt, Maryland 20771, USA.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Fagan
authors.affiliation: Department of Ecology, Evolution, and Environmental Biology, Columbia University, 10th Floor Schermerhorn Extension, New York, New York 10027, USA.
authors.forename: Ruth S
authors.initials: RS
authors.lastname: DeFries
authors.affiliation: U.S. Fish and Wildlife Service, P.O. Box 1306, Albuquerque, New Mexico 87103, USA.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Sesnie
authors.affiliation: Department of Geography, McGill University, 805 Sherbrooke Street, West Montreal, Quebec H3A 2K6, Canada.
authors.forename: J Pablo
authors.initials: JP
authors.lastname: Arroyo-Mora
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Connecticut, U-3043 75 North Eagleville Road, Storrs, Connecticut 06269-3043, USA.
authors.forename: Robin L
authors.initials: RL
authors.lastname: Chazdon
mesh_terms: D063147:Animal Distribution; D000818:Animals; D001717:Birds / Q000502:physiology*; D003364:Costa Rica; D052918:Environmental Restoration and Remediation / Q000379:methods*; D065928:Forests; D014329:Tropical Climate
keywords: 
  Glyphorynchus spirurus
  ; 
  Henicorhina leucosticta
  ; 
  Myrmeciza exsul
  ; 
  Thamnophilus atrinucha
  ; Costa Rica; fragmentation; functional connectivity; payments for environmental services; reforestation; tropical conservation; understory insectivores