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Biodiversity inventories are not yet complete, with potentially thousands of species unknown to science. This paper aims to (1) elucidate the historical discovery rate of endemic southern African marine fishes and (2) to estimate the number of potentially undescribed endemic marine fishes in the region using a statistical model and which factors (e.g. size/depth) contribute to unknown diversity. Thirdly, all species described globally for eight families (Blennidae, Clinidae, Gobiidae, Lutjanidae, Rajidae, Sciaenidae, Scyliorhinidae, Sparidae) were analysed to elucidate unknown diversity in these groups. The oceans of southern Africa, including Namibia, South Africa and Mozambique, encompassing sections of the south-eastern Atlantic Ocean and the western Indian Ocean. Literature surveys from a number of sources were carried out to compile lists of species descriptions from 1758 onwards. Species-accumulation curves were plotted for all endemic species, as well as for different components of size and depth. A maximum likelihood model was used to estimate the number of undescribed endemic marine fishes in southern Africa, as well as for all other categories, including global families. Fish discovery rates in southern Africa have varied with time. Estimates suggest that at least 25% of the total endemic fish fauna remain unknown and that size is the greatest predictor of whether a fish has been described. Smaller-sized fishes and those inhabiting shallow areas are most likely to be undersampled. It is likely that most undescribed fishes inhabit the subtropical/tropical waters of the east coast. At the current rate of fish description, it will take at least 50 years to describe the total endemic fish fauna. However, estimates of unknown species are probably higher because of cryptic species within currently recognized taxa. Climate change may also contribute to range expansions of marine species, further complicating the status of endemicity in southern African marine fishes. [ABSTRACT FROM AUTHOR]

Aim Human activities are largely responsible for the processes that threaten biodiversity, yet potential changes in human behaviour as a response to climate change are ignored in most species and site-based vulnerability assessments (VAs). Here we assess how incorporation of the potential impact of climate change on humans alters our view of vulnerability when using well-established site and species VA methodologies. Location Southern Africa. Methods Our baseline was two published studies that used accepted VA methodologies aimed at examining the direct impacts of climate changes on species and sites. The first identified potential shifts in the distributions of 164 restricted-range avian species, the second forecasted species turnover in 331 Important Bird and Biodiversity Areas (IBAs). We used a published spatially explicit assessment of potential climate change impacts on people to evaluate which species and sites overlap with human populations most likely to be impacted. By doing this, we were able to assess how the integration of potential climate impacts on human populations changes our perception of which species and sites are most vulnerable to climate change. Results We found no correlation between species and sites most likely to be impacted directly by climate change and those where the potential response of human populations could drive major indirect impacts. The relative vulnerability of individual species and sites shifted when potential impacts of climate change on human communities were considered, with more than one-fifth of species and one-tenth of sites moving from 'low' to 'high' risk. Main conclusions Standard VA methodologies that fail to consider how people are likely to respond to climate change will result in systematically biased assessments. This may lead to the implementation of inappropriate management actions, and a failure to address those species or sites that may be uniquely, or additionally, imperilled by the impacts of human responses to climate change. [ABSTRACT FROM AUTHOR]

Aim To review some of the applications in ecology and conservation biogeography of datasets derived from atlas projects. We discuss data applications and data quality issues and suggest ways in which atlas data could be improved. Location Southern Africa and worldwide. Methods Atlas projects are broadly defined as collections or syntheses of original, spatially explicit data on species occurrences. We review uses of atlas datasets and discuss data quality issues using examples from atlas projects in southern Africa and worldwide. Results Atlas projects must cope with tradeoffs between data quality and quantity, standardization of sampling methods, quantification of sampling effort, and mismatches in skills and expectations between data collectors and data users. The most useful atlases have a good measure of sampling effort; include data collected at a fine enough resolution to link to habitat variables of potential interest; have a sufficiently large sample size to work with in a multivariate context; and offer clear, quantitative indications of the quality of each record to allow for the needs of users who have specific demands for high-quality data. Main conclusions Atlases have an important role to play in biodiversity conservation and ideally should aim to offer reliable, high quality data that can withstand public, scientific and legal scrutiny. [ABSTRACT FROM AUTHOR]

Abstract. Floristic composition of 14 mesas (i.e. flat-top mountains) in four different study areas was investigated in southern African Nama Karoo. The study areas were arranged along a latitude gradient. Two simple questions were asked: are mesas potential conservation islands (a) in terms of re-colonization potential and (b) in terms of species richness? Detailed vegetation surveys along a transect from the plains to the top of each mesa were summarized to obtain species composition for the three main habitats: plain, slopes and plateau. Floristic similarities between plains and mesa habitats were used to answer question (a), and species richness was used to answer question (b). Geographic position, high within-area variability and elevation were found to largely influence the findings, resulting in only few consistent trends. The main findings of this study were, however: (1) mesas can act as sources for re-colonization as well as havens for species adapted to mountain habitats. (2) Considering total species richness, mesa habitats were richer in species than plains in the northern, but not the southernmost study area. (3) Scaled by area, mesa plateaus emerged as the most species-rich in all study areas. (4) Smaller and medium-sized mesas showed greater re-colonization potential, i.e. shared more species with their surrounding plains. (5) Medium-sized to larger mesas supported plant communities more distinct from the surrounding plains. (6) A cut-off point of approximately 240 m above the surrounding plain was indicated for the shift from ‘re-colonization’ to ‘remnant’ function. These findings stress the importance for the protection of mesa habitats in view of increasing human pressure on mountain habitats. [ABSTRACT FROM AUTHOR]

Conservation planning has hitherto concentrated largely on the representation of biodiversity patterns within a system of conservation areas. Only recently has there been an emphasis on retaining segments of the optimal conservation area by defining implementation priorities in terms of the irreplaceability of areas and their vulnerability to threatening processes. The conservation of ecological and evolutionary processes that sustain and generate biodiversity, a requirement for a system of conservation areas that promotes biodiversity persistence, has received very little attention. By designing conservation systems in order to represent spatial features as surrogates for ecological and evolutionary processes, and by scheduling the implementation of areas in order to minimise the impacts of threats on these processes, it is theoretically possible to achieve a conservation system that combines retention and persistence. Here we discuss the requirements for establishing a sustainable (retention + persistence) conservation system in southern Africa's Succulent Karoo, a mediterranean-climate desert that is very rich in plant species. Firstly, we discuss planning issues salient to both representation and design, and indicate the location, size and role in conservation of the spatial components (surrogates for processes) necessary for a system of conservation areas in the Succulent Karoo intended for retention + persistence. Next we lay out the requirements for a conservation system in the region and summarise some existing work on representation and retention of plant species. We then present a protocol for decision-making and apply it by designing a hypothetical system of conservation areas. Finally, we compare representation of Red Data Book plant species in a system identified for pattern retention with our similar-sized system designed for retention + persistence. The latter conserves 37% fewer species, indicating that design for persistence incurs a cost in... [ABSTRACT FROM AUTHOR]