Regional High-Resolution Benthic Habitat Data from Planet Dove Imagery for Conservation Decision-Making and Marine Planning

Abstract

High-resolution benthic habitat data fill an important knowledge gap for many areas of the world and are essential for strategic marine conservation planning and implementing effective resource management. Many countries lack the resources and capacity to create these products, which has hindered the development of accurate ecological baselines for assessing protection needs for coastal and marine habitats and monitoring change to guide adaptive management actions. The PlanetScope (PS) Dove Classic SmallSat constellation delivers high-resolution imagery (4 m) and near-daily global coverage that facilitates the compilation of a cloud-free and optimal water column image composite of the Caribbean’s nearshore environment. These data were used to develop a first-of-its-kind regional thirteen-class benthic habitat map to 30 m water depth using an object-based image analysis (OBIA) approach. A total of 203,676 km2 of shallow benthic habitat across the Insular Caribbean was mapped, representing 5% coral reef, 43% seagrass, 15% hardbottom, and 37% other habitats. Results from a combined major class accuracy assessment yielded an overall accuracy of 80% with a standard error of less than 1% yielding a confidence interval of 78%–82%. Of the total area mapped, 15% of these habitats (31,311.7 km2) are within a marine protected or managed area. This information provides a baseline of ecological data for developing and executing more strategic conservation actions, including implementing more effective marine spatial plans, prioritizing and improving marine protected area design, monitoring condition and change for post-storm damage assessments, and providing more accurate habitat data for ecosystem service models.

Planning for resilience: Incorporating scenario and model uncertainty and trade‐offs when prioritizing management of climate refugia

“…Shallow coral reef habitats (<30 m depth) were mapped by The Nature Conservancy (Schill et al, 2021) and were produced at 4m resolution from a mosaic of Planetscope Dove Classic satellite scenes acquired between 2017 and 2019. An object‐based classification using a ruleset that operated on surface reflectance, depth and geomorphic zone information was used to extract the classes, followed by manual corrections.…”

“…The ability to distinguish the difference between healthy and dead coral reefs is beyond the spectral capacity of the satellite imagery used to define the habitats and is particularly problematic for the coral/algae category, which tends to overestimate the amount of living reef. The overall accuracy of reef areas was, however, high, reaching 72% (Schill et al, 2021). To identify the unit of analysis, a 0.01 × 0.01 degree (about 1 km) grid was overlapped to the entire region of study and the total reef area was calculated for each cell.…”

Anthropause shows differential influence of tourism and a no‐take reserve on the abundance and size of two fished species

“…The expanded survey included uncharted waters in the northern reaches of the Exuma Sound, near a newly established but unregulated reserve in the southern Exumas, and along the northern edge of the Grand Bahama Bank (Supporting information Figure S1). The sites in the expanded survey were far from tourist lodgings, and therefore less likely to be visited, and were selected using the coral reef habitat layer in a recently developed Caribbean‐wide model (Schill et al, 2021).…”

“…). The sites in the expanded survey were far from tourist lodgings, and therefore less likely to be visited, and were selected using the coral reef habitat layer in a recently developed Caribbeanwide model (Schill et al, 2021).…”

Exploitation Drives Changes in the Population Connectivity of Queen Conch (Aliger gigas)

“…We compared our habitat area estimates to published seagrass habitat cover and conch fishing areas (SI Figure 3) including compilations of global geomorphic zones (UNEP-WCMC and Short 2021; Allen Coral Atlas, 2020;McKenzie et al, 2020;Schill et al, 2021); studies focused on jurisdictions or regional levels (Wabnitz et al, 2008;Tewfik et al, 2017;Leoń-Peŕez et al, 2019) and fishing sites (compiled in Prada et al, 2017). Estimates of seagrass area by jurisdiction were highly variable, and estimates of conch fishing areas were generally much lower than the highest estimates of seagrass cover.…”