Defining Critical Habitats of Threatened and Endemic Reef Fishes with a Multivariate Approach

Abstract

Understanding critical habitats of threatened and endemic animals is essential for mitigating extinction risks, developing recovery plans, and siting reserves, but assessment methods are generally lacking. We evaluated critical habitats of 8 threatened or endemic fish species on coral and rocky reefs of subtropical eastern Australia, by measuring physical and substratum-type variables of habitats at fish sightings. We used nonmetric and metric multidimensional scaling (nMDS, mMDS), Analysis of similarities (ANOSIM), similarity percentages analysis (SIMPER), permutational analysis of multivariate dispersions (PERMDISP), and other multivariate tools to distinguish critical habitats. Niche breadth was widest for 2 endemic wrasses, and reef inclination was important for several species, often found in relatively deep microhabitats. Critical habitats of mainland reef species included small caves or habitat-forming hosts such as gorgonian corals and black coral trees. Hard corals appeared important for reef fishes at Lord Howe Island, and red algae for mainland reef fishes. A wide range of habitat variables are required to assess critical habitats owing to varied affinities of species to different habitat features. We advocate assessments of critical habitats matched to the spatial scale used by the animals and a combination of multivariate methods. Our multivariate approach furnishes a general template for assessing the critical habitats of species, understanding how these vary among species, and determining differences in the degree of habitat specificity.

Benthic Habitats, as Derived from Classification of Side‐Scan‐Sonar Mapping Data, Are Important Determinants of Reef‐Fish Assemblage Structure in the Eastern Gulf of Mexico

“…The distribution of fish populations is often related to habitat characteristics ranging from microhabitats (e.g., substrate composition, attached biota) to broad‐scale habitat features (e.g., water depth) throughout their range (Anderson and Yoklavich ; Purcell et al. ; Bacheler and Ballenger ; Laman et al. ; Bacheler et al.…”

“…In this pilot study, the reef-fish assemblage structure in the Elbow differed significantly relative to the types of reef habitat that were identified through side-scan-sonar imagery. The distribution of fish populations is often related to habitat characteristics ranging from microhabitats (e.g., substrate composition, attached biota) to broad-scale habitat features (e.g., water depth) throughout their range (Anderson and Yoklavich 2007;Purcell et al 2014;Bacheler and Ballenger 2015;Laman et al 2015;Bacheler et al 2016). Determining which measures of habitat are the most important to the statistical design of a fisheries survey requires careful consideration.…”

Spatial differences across the French Pyrenees in the use of local habitat by the endangered semi‐aquatic Pyrenean desman (Galemys pyrenaicus)

“…This study stresses the importance of local habitat variables and supports previous findings on other species (e.g. reef fishes: Purcell et al ., ; lynx Lynx lynx : Bouyer et al ., ).…”

Biophysical Habitat Features Explain Colonization and Size Distribution of Introduced Trochus (Gastropoda)

“…In this study we were unable to study all potential habitats, therefore limiting our interpretations of niche breadth. Our data types and multivariate analyses have been used to examine niche breadth in a wide range of other marine species, so this is not a novel approach (Dumas et al, 2013;Purcell et al, 2014;Jankowski et al, 2015;Bennice et al, 2018), such information forms a basis for debate about the potential ecological consequences of translocations. We are also cautious about inferring any competition based on overlap in habitat associations, since it may be that food and refugia might not be limiting in many cases.…”