DOI: 10.5061/dryad.p8cz8w9pq
title: Data for: A tide of change – what we can learn from stories of marine conservation success

description: Rapid deterioration of marine habitats and biodiversity under cumulative
 stressors have led to increased efforts to rebuild marine life. Yet,
 successes of such endeavors do not have prominent visibility in recent
 assessments, although these examples are particularly needed to guide
 future actions to achieve our shared aspiration of a healthy ocean. Here,
 we provide a comprehensive assessment of 217 verified marine conservation
 successes across the world’s oceans and the main traits involved. Our
 findings reveal a balanced geography of success across the world’s oceans
 and that human stewardship is essential for driving conservation success,
 especially when different stakeholders work together in rebuilding marine
 life. This assessment should inform future actions and build confidence
 that reversing the trajectory of loss towards repairing ocean health is
 feasible. It also provides a basis for a ‘learning by doing’ approach in
 guiding conservation success through an understanding of the levers for
 success versus failure.
description: <strong>Retrieval of relevant
 reports</strong> For this dataset, the reports on
 marine conservation successes, which caused a significant positive change
 of an ecosystem component towards a previously documented state, were
 drawn from different sources (i.e., peer-reviewed publications,
 proceedings, dissertations, books, technical reports, popular science
 magazines, and grey literature). For
 the geographically-distributed search we used various combinations of the
 keywords ‘recovery’ AND/OR ‘stock increase’ AND/OR ‘population increase’
 together with keywords for the respective, different ocean components
 (such as ‘reef’, ‘mangrove’, or ‘whale’) to retrieve relevant reports from
 the major literature databases, i.e., Web-of- Science, Google Scholar,
 JSTOR, PubMed and ScienceDirect. In addition, we used the ‘snowball’
 sampling approach, where we manually searched the reference lists of the
 relevant publications on marine conservation successes to retrieve
 additional sources. We also further used a stratified search approach and
 distributed the search efforts across continents/regions among the
 contributing authors (e.g., North America, South America, Europe,
 South-East Asia, Australia and Micronesia, open ocean). This review does
 not aim to be exhaustive, as a formal meta-analysis aims at resolving
 metrics such as effect size, requiring complete experimental designs, but
 to identify levers of success and initiate a repository where future
 marine conservation and restoration successes can be reported by
 others. <strong>Pooling of conservation successes on related
 recovery efforts or locations</strong>   As a number of the search
 results reported on the same recovery effort or location (e.g., from
 different years or different habitats or species, but reported for the
 same location or population), these cumulative mitigation efforts were
 pooled here as a joint success case. These conservation successes were
 then categorized by having an influence on a local (i.e., distinct area,
 such as a specific bight, estuary, reef, or national park), regional
 (i.e., involving a broader area, such as a long stretch of coastline, or
 across national borders, as well if the action taken for recovery has an
 impact beyond a specific area), or basin level (i.e., conservation
 successes involving highly migratory species, such as cetaceans or sea
 turtles, and when impacts of recovery spread over a large area, often an
 entire ocean basin).   <strong>Categorization of conservation
 successes</strong>   We further categorized conservation successes into different
 ecosystems, habitats, or for marine taxa. This included different benthic,
 faunal habitats (i.e., benthic communities, coral reefs, and bivalve
 beds), vegetated coastal habitats (i.e., seagrass meadows, macroalgae
 stands, mangroves, and salt marshes), as well as different groups of
 marine megafauna (i.e., sea turtles, whales, seals, and other marine
 mammals), fishes (i.e., bony and cartilaginous), but also general
 improvements of the water quality (e.g., levels of specific organic and
 inorganic pollutants, or reduced eutrophication). The identified
 stressor(s) causing the initial habitat degradation or decline in species
 were also categorized and included overexploitation (e.g.,
 harvesting/hunting, unregulated fishing or deforestations), pollution
 (e.g., through chemicals, unregulated wastewater discharges, and oil
 spills), and other human disturbances (e.g., construction, sand
 extraction, dynamite fishing), and as well as climate change related
 pressures (e.g., high water temperatures and storm events).
   <strong>Consideration
 of socioeconomic zones</strong>   Furthermore, we grouped the
 success cases according to the socioeconomic zones, for which the
 conservation success was reported. These socioeconomic regions comprised
 the High-Income region (including Northern America, Europe, Australia, and
 New Zealand), Latin America and the Caribbean, the Middle East and North
 Africa (MENA), Sub-Saharan Africa, South Asia, as well as the East Asian /
 Pacific region. This division of the world countries into socioeconomic
 regions by Morales-Caselles et al. 2021<sup> </sup>included
 different geographical, cultural, and economic criteria (such as the Gross
 Domestic Product with a GDP constant in US$ averaged for the years
 2010-2016). Since the number of reported conservation successes varied
 between the socioeconomic regions, we calculated the percent contribution
 of the respective pressure (e.g., harvesting/fishing or pollution) to the
 overall pressures in that specific region. Thereby, we identified the
 socioeconomic region-specific stressors that initially led to a population
 decline or habitat degradation.   <strong>Consideration of involved
 stakeholders</strong>   Lastly, conservation successes were categorized according to
 the stakeholders that were involved in the recovery efforts, such as governments
 (through legislation, legal protection), industry (either direct – when
 actions taken were directly targeted to improve the ecosystem, or indirect
 when the recovery was just a byproduct), NGOs, local communities (e.g.,
 local fishermen or citizen groups), or scientists, as well as natural,
 unassisted recovery. When retrieving the actors involved, this reflected
 those credited with delivering the success, which may or may not have been
 the project initiators.