Biological Conservation 258 (2021) 109125 Contents lists available at ScienceDirect Biological Conservation journal homepage: www.elsevier.com/locate/biocon Policy analysis Designing effective protected area networks for multiple species Lynda Donaldson a,*,1, Jonathan J. Bennie b, Robert J. Wilson c,d, Ilya M.D. Maclean a a Environment & Sustainability Institute, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK b Centre for Geography and Environmental Science, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK c College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4PS, UK d Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid 28006, Spain ARTICLE INFO ABSTRACT Keywords: Protected area networks seek to ensure the persistence of multiple species, but their area and extent are limited Metapopulation by available land and conservation resources. Prioritising sites based on their quality, quantity, size, or con­ Cyperus papyrus nectivity is often proposed; potentially using the occupancy and metapopulation dynamics of individual Habitat network threatened species as surrogates for network effectiveness. However, the extent to which the dynamics of species Conservation planning with overlapping habitat requirements differ, and the implications of this for the optimal network designs for Connectivity Habitat quality multiple species, are rarely tested. We parameterise metapopulation models for 5 papyrus-specialist birds occupying a network of papyrus swamp in Uganda, each of which possess subtly different ecological charac­ teristics and habitat preferences. We estimate how each responds to different strategies based on prioritising patch size, number, quality and connectivity. The optimal approach differed depending on the metapopulation structure and characteristics of each species. The rank order of strategies also varied with the overall wetland area available and the desired persistence threshold. For individual species, prioritising habitat quality achieved the highest levels of persistence and population size for an equivalent amount of land area conserved. However, connected patches showed greatest overlap across species, thus the most effective strategy to conserve multiple species in the same network prioritised habitat connectivity. This emphasises the importance of individual species’ characteristics using the same habitat networks in conservation planning, and demonstrates the utility of prioritising protected sites based on the spatial connectivity of habitat patches, when aiming to conserve multiple species with differing or uncertain habitat requirements. 1. Introduction populations (D’Aloia et al., 2019), methods need to be developed and tested that consider the effects of habitat configuration on the persis­ The theories of island biogeography and metapopulation dynamics tence of species across protected area networks. (MacArthur and Wilson, 1967; Hanski, 1999), indicate that the occur­ Some general guidelines can be applied to the effects of habitat rence and abundance of species, and hence the likely effectiveness of configuration on species persistence. Metapopulation theory predicts protected areas, are related to the size and isolation of habitat islands. that colonization probability is greater in more connected patches (i.e. The principles proposed by these theories have thus been pivotal for the those closer to occupied patches), while local extinction rates are higher design of landscape-scale conservation initiatives (Donaldson et al., in small, low quality patches (Hanski, 1991, 1994; Moilanen and Hanski, 2017), and have led to recommendations for networks of protected areas 1998). Thus, protected area networks are recommended to consist of as a means of conserving biodiversity (Butchart et al., 2012). However, large, high quality, well connected sites (Lawton et al., 2010). But, with criteria for the designation of protected areas focus primarily on existing limited resources for conservation (McCarthy et al., 2012) and a land­ taxonomic irreplaceability (Dudley, 2008), and rarely consider the ef­ scape increasingly dominated by humans (Foley et al., 2005), optimising fects of the spatial configurationof habitats on likely persistence. Given all of these criteria is often impractical. Trade-offs may need to be made that drivers of environmental change, including habitat loss and climate between site size, quality and connectivity (Donaldson et al., 2017). change, produce dynamic changes in the distributions of species Metapopulation models have been used in fragmented landscapes to * Corresponding author. E-mail address: [email protected] (L. Donaldson). 1 Present address: Wildfowl & Wetlands Trust, Slimbridge, Gloucestershire, GL2 7BT, UK. https://doi.org/10.1016/j.biocon.2021.109125 Received 4 August 2020; Received in revised form 2 April 2021; Accepted 9 April 2021 Available online 18 May 2021 0006-3207/© 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). L. Donaldson et al. Biological Conservation 258 (2021) 109125 identify the most beneficial management strategies for the long-term responds to prioritising sites based on their size, quality and connec­ survival of individual species (Hanski et al., 1996b; Gutierrez, 2005), tivity. By comparing the outcomes among species, we test the suitability including the impact of enhancing the size, number or quality of patches of single-species metapopulation approaches to multi-species conser­ for persistence (Hanski and Thomas, 1994). Despite increasing interest vation, and assess the components of optimal planning for multiple in modelling the dynamics of two or more species residing in similar species sharing a habitat network. habitats (Gutierrez´ et al., 2001), or local communities of interacting species (Tilman et al., 1994), empirical tests of metapopulation ap­ 2. Materials and methods proaches to landscape-scale conservation planning typically continue to focus on the effects of single species alone (Etienne, 2004) rather than 2.1. Study system the influenceon multiple species. Yet protected area networks strive to represent whole communities of species (CBD, 2011), and chosen stra­ Work was conducted in papyrus swamps fringing Lake Bunyonyi, tegies should not negatively impact co-occurring species (Gutierrez´ south-west Uganda (01o17’S; 29o55’E; Fig. 1), where five species of et al., 2001) but instead balance the needs for all (Lawson et al., 2012). papyrus-specialist passerines are found: white-winged swamp-warbler Importantly, species often possess slightly different habitat re­ (Bradypterus carpalis), greater swamp-warbler (Acrocephalus rufescens quirements, even if associated with the same broad habitat type race foxi), papyrus canary (Crithagra koliensis), papyrus yellow warbler (Howard et al., 2000) and often vary in ecological characteristics, such (Calamonastides gracilirostris) and Carruthers’s cisticola (Cisticola carru­ as dispersal ability (Thomas, 2000) and dynamic responses to habitat thersi). Currently only papyrus yellow warbler is listed as threatened on availability (Glorvigen et al., 2013), that can lead to heterogenous re­ the IUCN Red List (IUCN, 2021), although all are estimated to be in sponses to different environmental factors (Falaschi et al., 2021). decline owing to extensive habitat loss and degradation (Maclean et al., However, detailed information on the habitat requirements or popula­ 2014) and are among the most inadequately protected bird species in the tion dynamics of most populations of species is lacking, and it is ques­ region (Maclean et al., 2011b). The presence of these birds has led to the tionable whether the dynamics of individual species can be used as a designation of an Important Bird and Biodiversity Area (IBA) at the reliable proxy for others because of variable needs (Meurant et al., north of the lake (BirdLife International, 2020), while Lake Bunyonyi 2018), and what the direct implications of this are for conservation and associated wetlands are proposed to be designated a Ramsar site for planning. Although prioritising species with distributions that encom­ their ecosystem service value and importance for biodiversity (Byar­ pass those of rare species may allow for a multi-species approach uhanga et al., 2001). All five species studied are primarily restricted to (Gutierrez´ et al., 2001), this may not be sufficient in networks con­ papyrus, though differ in ecological characteristics, such as feeding taining multiple threatened species that do not directly overlap. preferences (Britton, 1971), behaviour (Britton, 1978) and vegetation- Here we explicitly test the implications for selecting priority sites in structure preference (Maclean et al., 2003a, 2006; Donaldson et al., habitat networks based on the metapopulation dynamics of individual 2016, 2019). Their specific habitat requirements also differ slightly: versus multiple species, using a suite of specialist passerines primarily papyrus yellow warbler and Carruthers’s cisticola inhabit a broader restricted to papyrus (Cyperus papyrus) swamps in East and Central Af­ range of wetland vegetation types (Maclean et al., 2006). Although rica. Papyrus is a naturally fragmented wetland habitat because of its greater swamp-warbler is widely distributed in wetland habitats across limitation to wetland areas, and sites have become increasingly isolated Africa, race foxi is restricted to papyrus (Vande