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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]

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]

As countries commit to developing their ocean-based economies sustainably, it is critical to secure the underlying marine biodiversity and ecological processes. Ecosystem-based Marine Spatial Planning (MSP) can support achieving this; however, because competition for ocean space is increasing, biodiversity prioritisation must be spatially efficient, conflict-averse, and robust to secure marine biodiversity appropriately. South Africa has a long history and real-world success in spatial planning on land; we aim to draw on this experience to develop an approach by which the biodiversity sector's input to MSP can be developed, in the context of MSP unfolding in South Africa. We used Marxan to develop the first National Coastal and Marine Map of Critical Biodiversity Areas (CBAs) and Ecological Support Areas (ESAs). There were 976 biodiversity features and design elements, and the cost layer aimed to avoid conflict with 19 sea-use sectors and avoid more heavily impacted areas. Biodiversity targets were met in 27.0% of the planning domain (5.4% Marine Protected Areas (MPAs), 21.6% CBAs), with 6.6% for ESAs. Sea-use guidelines were developed based on a matrix of activity compatibility with the management objective for CBAs (keep or restore to natural) and ESAs (avoid further degradation), with MPAs managed through their gazetted regulations. The CBA Map and sea-use guidelines formed the basis for the marine biodiversity sector plan for inclusion in MSP. This approach can be broadly applied, even with limited data, as the basis for multi-sector negotiations. We share seven recommendations from our experience to guide planners from other countries. [Display omitted] • A framework for developing the biodiversity sector's input to MSP is conceptualised. • Efficient network of marine biodiversity priorities is identified for South Africa. • Priorities comprise: MPAs; Critical Biodiversity Areas; Ecological Support Areas. • Sea-use guidelines: based on activity compatibility with zone management objectives. • Outputs are the basis for formal multi-sector stakeholder engagement. [ABSTRACT FROM AUTHOR]

Representative and adequate reserve networks are key to conserving biodiversity. This begs the question, how much of which features need to be placed in protected areas? Setting specifically-derived conservation targets for most ecosystems is common practice; however, this has never been done for sandy beaches. The aims of this paper, therefore, are to propose a methodology for setting conservation targets for sandy beach ecosystems; and to pilot the proposed method using data describing biodiversity patterns and processes from microtidal beaches in South Africa. First, a classification scheme of valued features of beaches is constructed, including: biodiversity features; unique features; and important processes. Second, methodologies for setting targets for each feature under different data-availability scenarios are described. From this framework, targets are set for features characteristic of microtidal beaches in South Africa, as follows. 1) Targets for dune vegetation types were adopted from a previous assessment, and ranged 19–100%. 2) Targets for beach morphodynamic types (habitats) were set using species–area relationships (SARs). These SARs were derived from species richness data from 142 sampling events around the South African coast (extrapolated to total theoretical species richness estimates using previously-established species–accumulation curve relationships), plotted against the area of the beach (calculated from Google Earth imagery). The species-accumulation factor ( z ) was 0.22, suggesting a baseline habitat target of 27% is required to protect 75% of the species. This baseline target was modified by heuristic principles, based on habitat rarity and threat status, with final values ranging 27–40%. 3) Species targets were fixed at 20%, modified using heuristic principles based on endemism, threat status, and whether or not beaches play an important role in the species' life history, with targets ranging 20–100%. 4) Targets for processes and 5) important assemblages were set at 50%, following other studies. 6) Finally, a target for an outstanding feature (the Alexandria dunefield) was set at 80% because of its national, international and ecological importance. The greatest shortfall in the current target-setting process is in the lack of empirical models describing the key beach processes, from which robust ecological thresholds can be derived. As for many other studies, our results illustrate that the conservation target of 10% for coastal and marine systems proposed by the Convention on Biological Diversity is too low to conserve sandy beaches and their biota. [ABSTRACT FROM AUTHOR]