Advancing the integration of spatial data to map human and natural drivers on coral reefs

Abstract

A major challenge for coral reef conservation and management is understanding how a wide range of interacting human and natural drivers cumulatively impact and shape these ecosystems. Despite the importance of understanding these interactions, a methodological framework to synthesize spatially explicit data of such drivers is lacking. To fill this gap, we established a transferable data synthesis methodology to integrate spatial data on environmental and anthropogenic drivers of coral reefs, and applied this methodology to a case study location–the Main Hawaiian Islands (MHI). Environmental drivers were derived from time series (2002–2013) of climatological ranges and anomalies of remotely sensed sea surface temperature, chlorophyll-a, irradiance, and wave power. Anthropogenic drivers were characterized using empirically derived and modeled datasets of spatial fisheries catch, sedimentation, nutrient input, new development, habitat modification, and invasive species. Within our case study system, resulting driver maps showed high spatial heterogeneity across the MHI, with anthropogenic drivers generally greatest and most widespread on O‘ahu, where 70% of the state’s population resides, while sedimentation and nutrients were dominant in less populated islands. Together, the spatial integration of environmental and anthropogenic driver data described here provides a first-ever synthetic approach to visualize how the drivers of coral reef state vary in space and demonstrates a methodological framework for implementation of this approach in other regions of the world. By quantifying and synthesizing spatial drivers of change on coral reefs, we provide an avenue for further research to understand how drivers determine reef diversity and resilience, which can ultimately inform policies to protect coral reefs.

Long‐term dynamics and drivers of coral and macroalgal cover on inshore reefs of the Great Barrier Reef Marine Park

“…), and these generally varied, depending on the nature of the reef system and the density and activities of nearby human populations (Wedding et al. ), but not in all cases (Bruno and Valdivia ). Human population density may be a more important contributor on high‐nutrient, high‐sediment coastal reefs such as those studied here.…”

“…, Wedding et al. ). Repeated disturbances that kill corals, especially at broad spatial scales (e.g., cyclones and bleaching events), can trigger the persistent declines in coral cover that typically precede phase shifts to alternate (non‐coral dominated) states (Norström et al.…”

Building Coral Reef Resilience Through Spatial Herbivore Management

“…Areas with high sedimentation can suppress herbivory on coral reefs (Bellwood and Fulton, 2008) and increased sediment loads may result in more persistent algal coverage (Goatley and Bellwood, 2013;Goatley et al, 2016). In Hawai'i, sources of land-based pollution of particular concern include sedimentation from erosion (both natural and human-induced), nutrient flux from on-site sewage disposal systems, agriculture and golf-course runoff, and urban runoff from impervious surfaces (Lecky, 2016;Wedding et al, 2018). Effects of land-based pollution on coral health vary spatially with leeward, sheltered reefs having a stronger relationship to watershed health compared to windward, exposed coastlines with enhanced mixing (Rodgers et al, 2012).…”

The Moku System: Managing Biocultural Resources for Abundance within Social-Ecological Regions in Hawaiʻi

“…Owing to Hawai'i's orthographically driven climate patterns across the landscape and shoreline, bio-physical resources-such as sunlight, rainfall, temperature and wave energy [33,34]-ultimately drive natural resource abundance and the potential for cultivating biocultural resources via agro-ecological and aquaculture systems. While there are climatic similarities across moku, there are also key differences between moku.…”