Depth-structured sponge assemblages offer limited evidence for mesophotic refuge potential under the deep reef refuge hypothesis

Temperate mesophotic ecosystems (TMEs) have the potential to act as climate refugia for shallower benthic species impacted by environmental change. However, the extent to which mesophotic ecosystems might provide an ecological refuge, particularly for key functional groups like sponges, remains poorly known in temperate systems. Our study investigates sponge assemblage structure across a depth gradient at the Poor Knights Islands Marine Reserve, New Zealand, to assess the potential for mesophotic depths to act as ecological refuges for species inhabiting shallow water in the scenarios where mesophotic depths avoid shallower disturbances. Using ROV and SCUBA-based image surveys across three sites, sponge abundance data were collected from depths spanning 5 to 65 meters. Assemblage composition, species richness, and depth-dependent abundance patterns were analysed using nMDS, PERMANOVA, and linear regression. Results revealed high beta diversity across depths, with sponge assemblages stro..., , # Depth-structured sponge assemblages offer limited evidence for mesophotic refuge potential under the deep reef refuge hypothesis

Dataset DOI: [10.5061/dryad.7m0cfxq9b](https://doi.org/10.5061/dryad.7m0cfxq9b)

## Description of the data and file structure

This repository contains the data and R code used to analyse sponge assemblage structure across depth gradients at the Poor Knights Islands Marine Reserve, New Zealand. The analyses assess sponge assemblage composition, diversity, and depth-related abundance patterns in shallow and mesophotic reef zones, with the aim of evaluating the potential for mesophotic ecosystems to act as ecological refuges for shallow sponge species.

The dataset accompanies the manuscript:

*Depth-structured sponge assemblages offer limited evidence for mesophotic refuge potential under the deep reef refuge hypothesis*

### Files and variables

#### File: PK_all_sites_sponges.xlsx

**Description:** Excel file containing sponge percentage cover data derive...,