title: Effectiveness of protected areas in maintaining plant production.
abstract: Given the central importance of protected area systems in local, regional and global conservation strategies, it is vital that there is a good understanding of their effectiveness in maintaining ecological functioning. Here, we provide, to our knowledge, the first such global analysis, focusing on plant production, a "supporting" ecosystem function necessary for multiple other ecosystem services. We use data on the normalized difference vegetation index (NDVI) as a measure of variation in plant production in the core, boundary and surroundings of more than 1000 large protected areas over a 25 year period. Forested protected areas were higher (or similar), and those non-forested were lower (or similar), in NDVI than their surrounding areas, and these differences have been sustained. The differences from surrounding areas have increased for evergreen broadleaf forests and barren grounds, decreased for grasslands, and remained similar for deciduous forests, woodlands, and shrublands, reflecting different pressures on those surroundings. These results are consistent with protected areas being effective both in the representation and maintenance of plant production. However, widespread overall increases in NDVI during the study period suggest that plant production within the core of non-forested protected areas has become higher than it was in the surroundings of those areas in 1982, highlighting that whilst the distinctiveness of protected areas from their surroundings has persisted the nature of that difference has changed.
authors.affiliation: Department of Ecology, College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China. zytang@urban.pku.edu.cn
authors.forename: Zhiyao
authors.initials: Z
authors.lastname: Tang
authors.forename: Jingyun
authors.initials: J
authors.lastname: Fang
authors.forename: Jinyu
authors.initials: J
authors.lastname: Sun
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Gaston
mesh_terms: D003247:Conservation of Natural Resources / Q000706:statistics & numerical data*; D004463:Ecology / Q000706:statistics & numerical data; D063245:Plant Development; D013997:Time Factors