title: Scientific foundations for an IUCN Red List of ecosystems.
abstract: An understanding of risks to biodiversity is needed for planning action to slow current rates of decline and secure ecosystem services for future human use. Although the IUCN Red List criteria provide an effective assessment protocol for species, a standard global assessment of risks to higher levels of biodiversity is currently limited. In 2008, IUCN initiated development of risk assessment criteria to support a global Red List of ecosystems. We present a new conceptual model for ecosystem risk assessment founded on a synthesis of relevant ecological theories. To support the model, we review key elements of ecosystem definition and introduce the concept of ecosystem collapse, an analogue of species extinction. The model identifies four distributional and functional symptoms of ecosystem risk as a basis for assessment criteria: A) rates of decline in ecosystem distribution; B) restricted distributions with continuing declines or threats; C) rates of environmental (abiotic) degradation; and D) rates of disruption to biotic processes. A fifth criterion, E) quantitative estimates of the risk of ecosystem collapse, enables integrated assessment of multiple processes and provides a conceptual anchor for the other criteria. We present the theoretical rationale for the construction and interpretation of each criterion. The assessment protocol and threat categories mirror those of the IUCN Red List of species. A trial of the protocol on terrestrial, subterranean, freshwater and marine ecosystems from around the world shows that its concepts are workable and its outcomes are robust, that required data are available, and that results are consistent with assessments carried out by local experts and authorities. The new protocol provides a consistent, practical and theoretically grounded framework for establishing a systematic Red List of the world's ecosystems. This will complement the Red List of species and strengthen global capacity to report on and monitor the status of biodiversity.
authors.affiliation: Australian Wetlands Rivers and Landscapes Centre, University of New South Wales, Sydney, New South Wales, Australia. david.keith@unsw.edu.au
authors.forename: David A
authors.initials: DA
authors.lastname: Keith
authors.forename: Jon Paul
authors.initials: JP
authors.lastname: Rodríguez
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Rodríguez-Clark
authors.forename: Emily
authors.initials: E
authors.lastname: Nicholson
authors.forename: Kaisu
authors.initials: K
authors.lastname: Aapala
authors.forename: Alfonso
authors.initials: A
authors.lastname: Alonso
authors.forename: Marianne
authors.initials: M
authors.lastname: Asmussen
authors.forename: Steven
authors.initials: S
authors.lastname: Bachman
authors.forename: Alberto
authors.initials: A
authors.lastname: Basset
authors.forename: Edmund G
authors.initials: EG
authors.lastname: Barrow
authors.forename: John S
authors.initials: JS
authors.lastname: Benson
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Bishop
authors.forename: Ronald
authors.initials: R
authors.lastname: Bonifacio
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Brooks
authors.forename: Mark A
authors.initials: MA
authors.lastname: Burgman
authors.forename: Patrick
authors.initials: P
authors.lastname: Comer
authors.forename: Francisco A
authors.initials: FA
authors.lastname: Comín
authors.forename: Franz
authors.initials: F
authors.lastname: Essl
authors.forename: Don
authors.initials: D
authors.lastname: Faber-Langendoen
authors.forename: Peter G
authors.initials: PG
authors.lastname: Fairweather
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Holdaway
authors.forename: Michael
authors.initials: M
authors.lastname: Jennings
authors.forename: Richard T
authors.initials: RT
authors.lastname: Kingsford
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Lester
authors.forename: Ralph
authors.initials: R
authors.lastname: Mac Nally
authors.forename: Michael A
authors.initials: MA
authors.lastname: McCarthy
authors.forename: Justin
authors.initials: J
authors.lastname: Moat
authors.forename: María A
authors.initials: MA
authors.lastname: Oliveira-Miranda
authors.forename: Phil
authors.initials: P
authors.lastname: Pisanu
authors.forename: Brigitte
authors.initials: B
authors.lastname: Poulin
authors.forename: Tracey J
authors.initials: TJ
authors.lastname: Regan
authors.forename: Uwe
authors.initials: U
authors.lastname: Riecken
authors.forename: Mark D
authors.initials: MD
authors.lastname: Spalding
authors.forename: Sergio
authors.initials: S
authors.lastname: Zambrano-Martínez
mesh_terms: D044822:Biodiversity; D003247:Conservation of Natural Resources / Q000379:methods*; D017753:Ecosystem; D056727:Endangered Species; D008962:Models, Theoretical; D018570:Risk Assessment / Q000379:methods*