title: Measuring benefits of protected area management: trends across realms and research gaps for freshwater systems.
abstract: Protected areas remain a cornerstone for global conservation. However, their effectiveness at halting biodiversity decline is not fully understood. Studies of protected area benefits have largely focused on measuring their impact on halting deforestation and have neglected to measure the impacts of protected areas on other threats. Evaluations that measure the impact of protected area management require more complex evaluation designs and datasets. This is the case across realms (terrestrial, freshwater, marine), but measuring the impact of protected area management in freshwater systems may be even more difficult owing to the high level of connectivity and potential for threat propagation within systems (e.g. downstream flow of pollution). We review the potential barriers to conducting impact evaluation for protected area management in freshwater systems. We contrast the barriers identified for freshwater systems to terrestrial systems and discuss potential measurable outcomes and confounders associated with protected area management across the two realms. We identify key research gaps in conducting impact evaluation in freshwater systems that relate to three of their major characteristics: variability, connectivity and time lags in outcomes. Lastly, we use Kakadu National Park world heritage area, the largest national park in Australia, as a case study to illustrate the challenges of measuring impacts of protected area management programmes for environmental outcomes in freshwater systems.
authors.affiliation: School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory 0909, Australia v.adams@uq.edu.au.
authors.forename: Vanessa M
authors.initials: VM
authors.lastname: Adams
authors.affiliation: Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory 0909, Australia.
authors.forename: Samantha A
authors.initials: SA
authors.lastname: Setterfield
authors.affiliation: Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory 0909, Australia School of Earth and Environment, University of Western Australia, Perth, Western Australia 6009, Australia.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Douglas
authors.affiliation: Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Kennard
authors.affiliation: Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory 0909, Australia.
authors.forename: Keith
authors.initials: K
authors.lastname: Ferdinands
mesh_terms: D000818:Animals; D044822:Biodiversity; D003247:Conservation of Natural Resources / Q000379:methods* / Q000639:trends; D017753:Ecosystem; D004787:Environmental Pollution / Q000517:prevention & control; D005618:Fresh Water; D058865:Introduced Species; D015876:Northern Territory; D000068316:Parks, Recreational; D010944:Plants
keywords: Kakadu National Park; freshwater ecosystems; impact evaluation; protected area management