Effectiveness of Surrogate Taxa in the Design of Coral Reef Reserve Systems in the Indo‐Pacific

Abstract

Implementing systematically designed reserve systems is crucial to slowing the global decline of coral reef health and diversity. Yet, the paucity of spatial data for most coral reef taxa often requires conservation planners to design reserve systems based only on a subset of taxonomic groups as surrogates for all other taxa. In terrestrial systems the validity of surrogates for reserve design is established by testing for cross-taxon congruence (similarities in spatial patterns of species richness), but this concept has rarely been examined in the marine environment. We tested the suitability of taxa as conservation representation surrogates of coral reef species richness across the Indo-Pacific, based on species lists of fishes, corals, and mollusks from 167 sites. First, we tested the relevance of cross-taxon congruence patterns to predict these surrogacy patterns. We determined congruence between taxonomic groups by conducting a correlation analysis of dissimilarity values between pairs of sites. We then evaluated how well each taxonomic group represented the other groups in a marine reserve system selected by a greedy reserve-selection algorithm relative to reserve systems selected by chance. No taxonomic group we examined was a reliable surrogate for the other groups such that site selection based on that group always represented other taxa significantly better than random selection of sites. Sites selected based on hard corals represented the other taxonomic groups in a reserve system worse than randomly selected sites. Although we found high cross-taxon congruence between fishes and corals and between corals and mollusks, for some regions cross-taxon congruence was not always a reliable indicator of the ability of one taxonomic group to efficiently represent another in a reserve system. We concluded that in Indo-Pacific coral reef ecosystems one can only be sure that a target taxon is efficiently represented in a reserve system when data on that taxon are used to select a reserve system.

Regional Conservation Status of Scleractinian Coral Biodiversity in the Republic of the Marshall Islands

“…The finding of spatial heterogeneity in the RMI coral meta-community is consistent with another study that examined the occupancy-abundance patterns of Acropora corals [35], but it is inconsistent with other published literature that suggest coral communities are homogenous and highly predictable across spatial scales [53][54][55][56][57][58][59]. While this may be true to an extent at the genus-level, it does not hold up at the species-level.…”

Congruence in demersal fish, macroinvertebrate, and macroalgal community turnover on shallow temperate reefs

“…While conservation management of communities often assumes strong biological surrogacy (Rodrigues and Brooks 2007), our work represents one of the few marine studies where data are available to test this assumption across broad spatial scales (Beger et al 2007, O'Hara 2008, Williams et al 2010, Mellin et al 2011, Sutcliffe et al 2012. We have used a novel statistical technique, gradient forest modeling (GFM), to predict patterns of compositional turnover of fishes, invertebrates, and macroalgal assemblages across a substantial section of southern Australian coastline.…”

Distinction between effective pattern-based and selection-based biodiversity surrogates is essential: caveats for managers

“…Examples are found in the literature. For coral reefs, Beger et al (2007), who investigated cross-taxa surrogacy, gave a good example that contradicts the idea that a good pattern-based surrogate is a good selection-based surrogate. They showed that even though there is a spatial correlation between a variable X (fish, corals or molluscs) diversity and a variable Y (fish, corals, molluscs) diversity, the design of a marine protected area based on X would lead to a poor representation of Y diversity.…”

“…They focused on (1) testing selected taxa as surrogates of total reef biodiversity (Beger et al 2007), (2) testing of selected taxa as surrogates of other selected taxa (Beger et al 2003(Beger et al , 2007, and (3) testing coral reef habitats as surrogates of taxa, ecological functions and ecosystem services (Mumby et al 2008, Dalleau et al 2010. Generally, these studies have avoided mixing the selection-based and pattern-based concepts, and even clearly pointed out the paradox (Beger et al 2007, Dalleau et al 2010.…”