title: Pseudoreplication in tropical forests and the resulting effects on biodiversity conservation.
abstract: Tropical forest ecosystems are threatened by habitat conversion and other anthropogenic actions. Timber production forests can augment the conservation value of primary forest reserves, but studies of logging effects often yield contradictory findings and thus inhibit efforts to develop clear conservation strategies. We hypothesized that much of this variability reflects a common methodological flaw, simple pseudoreplication, that confounds logging effects with preexisting spatial variation. We reviewed recent studies of the effects of logging on biodiversity in tropical forests (n = 77) and found that 68% were definitively pseudoreplicated while only 7% were definitively free of pseudoreplication. The remaining proportion could not be clearly categorized. In addition, we collected compositional data on 7 taxa in 24 primary forest research plots and systematically analyzed subsets of these plots to calculate the probability that a pseudoreplicated comparison would incorrectly identify a treatment effect. Rates of false inference (i.e., the spurious detection of a treatment effect) were >0.5 for 2 taxa, 0.3-0.5 for 2 taxa, and <0.3 for 3 taxa. Our findings demonstrate that tropical conservation strategies are being informed by a body of literature that is rife with unwarranted inferences. Addressing pseudoreplication is essential for accurately assessing biodiversity in logged forests, identifying the relative merits of specific management practices and landscape configurations, and effectively balancing conservation with timber production in tropical forests.
authors.affiliation: Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720-3114, U.S.A. bsramage@berkeley.edu
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Ramage
authors.forename: Douglas
authors.initials: D
authors.lastname: Sheil
authors.forename: Hannah M W
authors.initials: HM
authors.lastname: Salim
authors.forename: Christine
authors.initials: C
authors.lastname: Fletcher
authors.forename: Nur-Zati A
authors.initials: NZ
authors.lastname: Mustafa
authors.forename: Joann C
authors.initials: JC
authors.lastname: Luruthusamay
authors.forename: Rhett D
authors.initials: RD
authors.lastname: Harrison
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Butod
authors.forename: Ahmad Dzamir
authors.initials: AD
authors.lastname: Dzulkiply
authors.forename: Abd Rahman
authors.initials: AR
authors.lastname: Kassim
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Potts
mesh_terms: D044822:Biodiversity; D056808:Biostatistics; D003247:Conservation of Natural Resources / Q000379:methods*; D017753:Ecosystem; D008954:Models, Biological; D011897:Random Allocation; D015203:Reproducibility of Results; D012107:Research Design / Q000592:standards; D014329:Tropical Climate