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Accurate assessments of ecosystem condition are needed to inform management processes such as systematic conservation planning and protected area expansion, marine spatial planning and other effective area‐based conservation measures. Yet measuring the condition of dynamic and often largely inaccessible marine ecosystems is extremely difficult and presents a global challenge.Broad‐scale cumulative impact assessments have been used in South Africa as a proxy for marine ecosystem condition in national assessments and reporting because the data are more readily available, and knowledge exists on the impacts of various human activities (or pressures) on marine ecosystems. While useful for national reporting, assessments based on in situ ecological data are also needed at finer scales relevant to management.Applying the HELCOM BEAT approach, this study used in situ ecological data to identify potential methods and indicators that can be applied in South Africa to conduct integrated ecosystem assessments and to assess the suitability of current cumulative impact assessments as a proxy for condition.Aggregated fish indicators demonstrated greater sensitivity to varying human pressures compared with benthic community indicators, with responsiveness differing by location. Notably, site‐level differences in empirical condition emerged that broad‐scale cumulative assessments often missed. The study thus highlighted the varying suitability of cumulative impact scores as proxies for condition, indicating their reliability for fish communities. However, this is also dependent on the pressure types included, the biotic indicators used and the area of focus.Conservation decisions based solely on cumulative impact scores could misrepresent the actual condition of the environment, which makes it difficult to make management decisions, especially at finer scales. As such, conservation initiatives need to be regionally adapted to effectively address the unique pressures and conditions of each area and should be tailored to account for fine‐scale variability, instead of adopting a one‐size‐fits‐all approach. [ABSTRACT FROM AUTHOR]

South Africa sought to implement an ecologically representative Marine Protected Area (MPA) network to achieve biodiversity and fisheries management goals with least impact on offshore stakeholders. The result was the declaration of a spatially efficient network representing 131 of 150 marine ecosystem types (87%) in 5.4% of ocean area. We outline the 15‐year process from planning to implementation of 20 new MPAs, including contentious areas recognized as important for conservation decades ago. Systematic Conservation Planning (SCP) supported by 532 data layers and an inclusive stakeholder process identified priority areas, reduced conflict and guided complex trade‐offs. Multiple scenarios and iterative improvements increased transparency, supported ocean zonation and achieved balanced compromises while maintaining conservation objectives. Key challenges, enabling factors and lessons are shared. We demonstrate that flexible, evidence‐based SCP together with adaptive social processes that are alert to opportunities can support implementation of representative MPA networks aligned to ocean economy goals. South Africa used systematic planning and inclusive stakeholder engagement to protect 87% of its 150 marine ecosystem types in just 5% ocean area [ABSTRACT FROM AUTHOR]

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Ecology and biodiversity research are underpinned by species richness patterns and their environmental drivers. However, a key topic in this discussion is the accuracy of these patterns which are greatly dependent on species detection probabilities. Due to variations in detection of species, true ecological patterns may be distorted. This is particularly true for subtidal macro‐infaunal communities. We tested three hypothesized relationships between marine benthic macrofaunal diversity and depth using species richness per site estimated with a capture–recapture heterogeneity model that accounts for variable detection probabilities. These metrics were based on data from 42 replicated sites across the continental shelf of the Southern Benguela. Average detection probability decreased with greater depth but species richness increased along the same depth gradient. The conflation of these trends in observed diversity data resulted in a positively near‐linear depth–diversity relationship, while accounting for variable species detection revealed a much stronger relationship. Ignoring species detection in ecosystems with imperfect detection could therefore distort species richness patterns, which has implications for ecological theory, management and conservation. [ABSTRACT FROM AUTHOR]

Aim The species-area relationship-based method of setting habitat-specific conservation targets assumes that detectability of species is perfect. However, this assumption is often violated. This paper aimed to combine species-area relationship ( SAR)-based target setting with multispecies occupancy models to better represent communities with a large proportion of rare species, such as marine invertebrate macrofauna, include variable species detection and quantify uncertainty around conservation targets. Location South African West Coast continental shelf. Methods The macro-infaunal dataset used in these analyses consisted of 427 species from 42 sites and 220 samples. To examine the effect of variable species detection and include uncertainty around conservation targets, we compared asymptotic estimator-based targets with those based on multispecies site occupancy models ( MSOMs) in a Bayesian framework, which allowed us to account for the observation process and quantify uncertainty more comprehensively. Results Targets based on MSOM were generally higher than those based on asymptotic estimators, with wider credible intervals. Between 10% and 15% (95% credible interval) of the area should be protected to represent 80% of the species, with the exception of one habitat with many common species that had a conservation target of 2%. Main conclusions Detection error-corrected targets based on MSOM are higher than uncorrected targets based on asymptotic estimators for habitats with lower detection and higher proportions of rare species. Our estimated conservation targets are close to the 10% target for marine habitats set by the Convention of Biological Diversity and in line with international studies but should be considered minimum targets as they do not take into account species persistence. Our results affirm the value of the modified SAR approach, which is applicable to any marine or terrestrial ecosystem. Unlike earlier methods, our modification naturally quantifies uncertainty in estimated conservation targets providing a measure of target robustness for decision-makers. [ABSTRACT FROM AUTHOR]