Maputaland-Pondoland-Albany Research Articles

Phylogeography of two codistributed terrestrial snails in the Maputaland–Pondoland–Albany biodiversity hotspot, South Africa

Abstract We investigated the evolutionary patterns of two forest-dwelling endemic terrestrial snails (Gittenedouardia spadicea and Maizania wahlbergi) in the Maputaland–Pondoland–Albany biodiversity hotspot in South Africa to examine the degree of phylogeographical congruence between the two species. Phylogenetic relationships and divergence time estimations within each species were inferred using the combined mitochondrial DNA (mtDNA) sequence dataset for the cytochrome c oxidase subunit I (COI) and large subunit ribosomal RNA (16S rRNA). In addition, the rapidly evolving COI datasets were used to infer intraspecific genetic structure and population differentiation within both species. Phylogeographical concordance factor (PCF) analysis was used to statistically estimate the degree of congruence between the two species at localities where both species were sampled. Phylogenetically, G. spadicea exhibited two clades that diverged during the Plio/Pleistocene, while M. wahlbergi formed a single shallow clade that showed Pleistocene divergence. The haplotype networks for the COI locus demonstrated evidence of geographical and genetic isolation within both species. PCF analysis demonstrated partial phylogeographical concordance, suggesting that the two species may have been affected by similar ancient climatic events. Traits other than poor dispersal capabilities and limited gene flow may also influence how a species responds to fluctuating climate change.

Land snail biogeography and endemism in south-eastern Africa: Implications for the Maputaland-Pondoland-Albany biodiversity hotspot.

Invertebrates in general have long been underrepresented in studies on biodiversity, biogeography and conservation. Boundaries of biodiversity hotspots are often delimited intuitively based on floristic endemism and have seldom been empirically tested using actual species distributions, and especially invertebrates. Here we analyse the zoogeography of terrestrial malacofauna from south-eastern Africa (SEA), proposing the first mollusc-based numerical regionalisation for the area. We also discuss patterns and centres of land snail endemism, thence assessing the importance and the delimitation of the Maputaland-Pondoland-Albany (MPA) biodiversity hotspot for their conservation. An incidence matrix compiled for relatively well-collected lineages of land snails and slugs (73 taxa in twelve genera) in 40 a priori operational geographic units was subjected to (a) phenetic agglomerative hierarchical clustering using unweighted pair-group method with arithmetic means (UPGMA), (b) parsimony analysis of endemicity (PAE) and biotic element analysis (BEA). Fulfilling the primary objective of our study, the UPGMA dendrogram provided a hierarchical regionalisation and identified five centres of molluscan endemism for SEA, while the PAE confirmed six areas of endemism, also supported by the BEA. The regionalisation recovers a zoogeographic province similar to the MPA hotspot, but with a conspicuous westward extension into Knysna (towards the Cape). The MPA province, centres and areas of endemism, biotic elements as well as the spatial patterns of species richness and endemism, support the MPA hotspot, but suggest further extensions resulting in a greater MPA region of land snail endemism (also with a northward extension into sky islands—Soutpansberg and Wolkberg), similar to that noted for vertebrates. The greater MPA region provides a more robustly defined region of conservation concern, with centres of endemism serving as local conservation priorities.

Native honeybees as flower visitors and pollinators in wild plant communities in a biodiversity hotspot

AbstractWestern honeybees (Apis mellifera L.), native to Europe and Africa, have been transported worldwide and are now one of the most important global crop pollinator species. Although the relative contribution of honeybees to global crop pollination is increasingly recognized, relatively little is known about their importance as pollinators in wild plant communities. The only remaining wild and unmanaged western honeybee populations are in Africa. We investigated the importance of honeybees as pollinators of diverse wild plant communities in two protected areas within the Maputaland–Pondoland–Albany biodiversity hotspot in South Africa. Sites were far from any known areas of beekeeping, and so all honeybees were most likely from wild colonies. Honeybees visited a large proportion of flowering plant species within these two communities (40% and 35%) and also provided a substantial proportion of visits to the plants they visited (40% and 32%, respectively). However, when pollinator importance indices (based on abundance and the size and purity of pollen loads) were calculated for a small subset of plants, honeybees were only important pollinators of 29% of the plants they visited. Our data provide a first step in determining the importance of honeybees as flower visitors and pollinators in wild plant communities and the potential impacts of honeybee declines on these highly diverse grassland ecosystems. Our work suggests that many plants in the grassland systems studied are visited by non‐Apis flower visitors and therefore that conservation efforts should also focus on these pollinator groups.

An ecological network is as good as a major protected area for conserving dragonflies

Freshwaters are highly threatened ecosystems, with agro-forestry being a major threat to sub-tropical wetlands. In the Maputaland–Pondoland–Albany global biodiversity hotspot of South Africa, large-scale ecological networks (ENs) of remnant vegetation have been set aside with the aim of mitigating the adverse effects of plantation forestry. However, the effectiveness of these ENs for maintaining freshwater biodiversity, especially that of still waters, is poorly known. In response, we compare mud wallows of large mammals, ponds and small marshes in an EN with those in an adjacent World Heritage Site protected area (PA) as reference. For this comparison we used dragonfly adults in view of their effectiveness as bioindicators. A total of 47 species was recorded at 105 sites. The EN shared 74% of its species with the PA. However, equal numbers of range restricted species were recorded from the EN and the PA. Five species were recorded as particular to the EN and seven to the PA, probably due to habitat heterogeneity across this type of landscape. Pond size, habitat heterogeneity, elevation and dissolved oxygen were important determinants for species richness and diversity. Proximity of plantation trees had only a minor effect, and then only on species composition. Mud wallows were the poorest habitat in terms of dragonfly diversity, owing to the intense disturbance. Wallows, ponds and marshes were largely complementary in their species composition. Overall, the freshwater system in the EN was a good surrogate for that in the PA, indicating the effectiveness of these ENs for maintaining the dragonfly assemblage.

Improving the surrogacy effectiveness of charismatic megafauna with well‐surveyed taxonomic groups and habitat types

Summary Conservation planning often relies on the use of surrogates for representing many aspects of biodiversity. Previous tests on the effectiveness of charismatic mammals as biodiversity surrogates have suffered from the lack of fine‐resolution data and produced varied and contrasting results. In this study, we used unique high‐resolution data for more than 600 biodiversity features from the Maputaland–Pondoland–Albany global biodiversity hot spot to assess how the surrogacy effectiveness of the ‘Big Five’ charismatic mammal species could be improved. We found that combining the ‘Big Five’ charismatic mammal species with well‐known and surveyed taxonomic groups, such as birds, amphibians and reptiles, and habitat types, which can be mapped quickly and inexpensively, increases the representation of poorly surveyed taxonomic groups, such as endemic and threatened invertebrate and plant species, as well as other mammal species. In particular, habitat types were found to be an integral component of a successful surrogate strategy. Nevertheless, a broad cross‐taxon surrogate group composed of the ‘Big Five’, birds, amphibians and reptiles, was found to be a more effective surrogate than habitat types on their own. Meanwhile, other taxonomic groups and habitat types were not effective surrogates for the ‘Big Five’ charismatic species. As charismatic mammals have an important marketing value, they can be promoted to generate funding, which can then facilitate the implementation of conservation action and cover management costs, thereby indirectly benefiting other threatened biodiversity. Synthesis and applications. While some geographic areas and taxa have been extensively studied, detailed information about the distributions of species is missing for much of the world. This study provides important information that can have operational relevance to prioritize areas for conservation action in areas of the world with poor data on biodiversity. We found that other taxa are not good surrogates for charismatic mammal species. We also found that habitat types are a necessary component of surrogacy strategies that cover plants and insects. Overall, a combination of habitat types and charismatic mammals, complemented with other well‐known taxa (birds, amphibians and reptiles), provided the highest surrogacy effects.

Empirical evidence for reduced protection levels across biodiversity features from target-based conservation planning

Target-based planning is an integral component of systematic conservation planning. Using empirical data, we investigate a prior conceptual proposition that target-based planning may lead to lower average protection levels across biodiversity features due to its prescriptive nature where conservation outcome is measured in terms of achievement of many independently developed targets. We used spatial distribution models and externally provided targets set for 253 biodiversity features from the Maputaland–Pondoland–Albany hotspot and compared target-based planning to alternative approaches, such as maximum-utility planning, which can operate without the specification of strict targets. We found that target-based planning retained on average a significantly lower fraction of the distributions of all biodiversity features than did alternative methods. This sub-optimality fundamentally follows from the nestedness of species distributions being ignored in target setting, leading to investment in features that occur in relatively species-poor and expensive areas. Consequently, benefit-based alternatives to target-based planning will achieve higher overall conservation performance.

Vertebrate distributions indicate a greater Maputaland-Pondoland-Albany region of endemism

The Maputaland-Pondoland-Albany (MPA) biodiversity hotspot (~274 316 km 2 ) was primarily recognised based on its high plant endemism. Here we present the results of a qualitative biogeographical study of the endemic vertebrate fauna of south-eastern Africa, in an exercise that (1) refines the delimitation of the MPA hotspot, (2) defines zoogeographical units and (3) identifies areas of vertebrate endemism. Initially we listed 62 vertebrate species endemic and 60 near endemic to the MPA hotspot, updating previous checklists. Then the distributions of 495 vertebrate taxa endemic to south-eastern Africa were reviewed and 23 endemic vertebrate distributions (EVDs: distribution ranges congruent across several endemic vertebrate taxa) were recognised, amongst which the most frequently encountered were located in the Eastern Escarpment, central KwaZulu-Natal, Drakensberg and Maputaland. The geographical patterns illustrated by the EVDs suggest that an expansion of the hotspot to incorporate sections of the Great Escarpment from the Amatola-Winterberg-Sneeuberg Mountains through the Drakensberg to the Soutpansberg would be justified. This redefinition gives rise to a Greater Maputaland-Pondoland-Albany (GMPA) region of vertebrate endemism adding 135% more endemics with an increase of only 73% in surface area to the MPA hotspot. The GMPA region has a more natural boundary in terms of EVDs as well as vegetation units. An accurate delimitation of this hotspot, as well as a better understanding of biogeography in the region, would greatly benefit conservation planning and implementation. Towards these aims, we used EVDs to delimit non-overlapping zoogeographical units (including 14 areas of vertebrate endemism), facilitating numerical biogeographical analyses. More importantly, this study opens up possibilities of refining hotspot delimitation and identifying local conservation priorities in regions of the world where data do not allow numerical analyses.

The effect of herbivores and humans on the Sand Forest species of Maputaland, northern KwaZulu‐Natal, South Africa

AbstractSand Forest in the Maputaland region of KwaZulu‐Natal in South Africa is deemed the most valuable, but also probably the most complex vegetation type of this part of the Maputaland–Pondoland–Albany hotspot of biodiversity. However, Sand Forest is under threat from the current human population growth in that region as well as from uncontrolled increases in wild herbivore numbers in conservation areas. The present study compares the impacts of herbivores and humans on the state of woody resources between two sites under differing utilisation regimes. Sand Forest was found to be a complex association of tree assemblages defined by different canopy and subcanopy properties. Although marked differences in the abundance of selected species were noted at the two sites, the Sand Forest remained dominated by fine‐grained species under both utilisation regimes. The fine‐grained nature of Sand Forest implies that regeneration depends on the creation of small canopy gaps either by natural processes, humans or elephants, while the creation of large gaps could transform it into woodland. Management of conservation areas where Sand Forest occurs should therefore concentrate efforts on regulating animal populations to levels that provide gap properties that favour forest regeneration.

Evaluating the adequacy of reserves in the Tembe–Tshanini Complex: a case study in Maputaland, South Africa

AbstractThe aim of this study was to determine the minimum conservation area needed to conserve vegetation types and their landscape and to apply it to an area in KwaZulu-Natal, South Africa, which is within the Maputaland Centre of Plant Endemism and part of the Maputaland–Pondoland–Albany biodiversity hotspot. Outside conservation areas this Centre of Plant Endemism is under threat from human utilization. We used a method initially designed to determine minimum conservation areas for rare plant species, which we adapted from its original country and context, to determine minimum conservation areas for landscape species in Maputaland’s little-documented environment. The minimum area required for conservation was established for the Sand Forest and Woodland vegetation types in the region. We found that sufficient habitat is presently conserved to preserve the Sand Forest but not the Woodlands. The method holds promise to provide answers to critical conservation issues in lesser-known environments and, although relatively difficult to establish for the first time, is an efficient and easy to use tool that can be refined once more knowledge becomes available.

Reserve selection using Red Listed taxa in three global biodiversity hotspots: Dragonflies in South Africa

The Red List can be used a gauging tool by conservationists to assess which species require focused conservation attention. Mapping the relative distributions of species, and identification of centers of richness, endemism and threat are a first step towards site-oriented conservation action. We use here a specially developed biodiversity index, based on three weighted sub-components assigned to each species: geographical distribution, Red List status, and sensitivity to habitat change. We test this approach using what is called here the Dragonfly Biotic Index (DBI) to prioritize sites for conservation action, with special emphasis on species occurrence in three global hotspots in southern Africa. Using a selected set of the 23 top prioritized sites, we compare the DBI’s performance to that of a rarity–complementarity algorithm. As with several other taxa, local endemism levels are highest in the Cape Floristic Region (CFR), while richness is highest in the north east, particularly in the stream systems of the Maputaland–Pondoland–Albany (MPA) hotspot. Red Listed Odonata species are also concentrated in the CFR, while richness is highest in the MPA hotspot. Site prioritization using the DBI reveals that CFR sites protect Red Listed taxa rather well, despite the fact that catchments are only partially protected. The DBI demonstrates high levels of redundancy in representing Red Listed species, in other words, the same species are represented in several catchments. The value in the DBI thus lies in maximizing redundancy (i.e. representation) of globally Red Listed species. The rarity–complementarity algorithm represents all species, but without greater emphasis on the rare and threatened (i.e. Red Listed) species. We conclude that the DBI is of great value in selecting biodiversity hotspots, while the algorithm is useful for selecting complementarity hotspots. We identify protection gaps and thus recommend continued searches in centers of endemism and existing reserves, as well as gap areas. These searches will hone Red List assessments and identify priority sites, as well as monitor already-identified sites for changes in quality of habitat.

A spatial and temporal analysis of Sand Forest tree assemblages in Maputaland, South Africa

Maputaland is a centre of plant endemism, within the Maputaland–Pondoland–Albany hotspot of biodiversity shared by Mozambique and South Africa. The Sand Forest vegetation is the most valuable vegetation type in this region due to the endemics it harbours, but it is currently under threat from growing animal population densities within conserved areas and from a growing human population outside. To improve our understanding of Sand Forest dynamics the present study investigated the woody plant assemblages in Tembe Elephant Park. A total of 59 plots were sampled and analysed using classification and ordination methods. The results indicate that Sand Forest in Tembe is a complex assemblage of at least three floristically and structurally distinct woody communities. An ordination of the combined results from the present study together with two other studies could link the floristics and structure of the Sand Forest to the level of disturbance by herbivores and humans. Large herbivores induce both structural and floristic changes in the Sand Forest of Tembe Elephant Park and a lack of disturbance in the nearby Tshanini Community Conservation Area leads to a state of equilibrium. The results therefore suggest that Sand Forest dynamics and complexity may be strongly linked to small- to medium-scale animal disturbance.

Speciation and radiations track climate transitions since the Miocene Climatic Optimum: a case study of southern African chameleons

AbstractAim The high amount of species diversity concentrated in southern Africa has been attributed to palaeoclimatic factors, and the timing of radiations in some taxa corresponds to global palaeoclimatic trends. Using dwarf chameleons (Bradypodion: Chamaeleonidae) as a model system, we explored the relationship between palaeoclimatic fluctuations and cladogenesis with respect to both temporal and spatial patterns in an effort to understand the process of speciation in southern Africa.Location South Africa, with particular emphasis on the Cape Floristic Region and the Maputaland–Pondoland–Albany hotspot.Methods Mitochondrial sequence data (ND2 and 16S) were used to estimate the timing of major radiations and to examine the number of lineages through time. A dated phylogeny was constructed using Bayesian phylogenetic reconstruction, and a Bayesian relaxed molecular clock was used to estimate divergence times. Spatial data and lineage‐through‐time plots were used to identify geographic regions that underwent diversification in connection with major climatic events. Both parsimony and likelihood optimizations of habitat type on the phylogeny were used to determine whether major habitat shifts have occurred. On a coarse scale (half‐degree grid cells), phylogenetic diversity (sum of the branch lengths linking terminals) was compared with species richness (absolute number of species) to identify areas of conservation importance.Results The complete species phylogeny of dwarf chameleons shows that the timing and mode of diversification exhibit spatio‐temporal patterns that link to phases in the evolution of southern Africa’s climate over the last 14 Myr. Optimizations of habitat on the phylogenetic tree show a progression from closed to open habitats since the Mid‐Miocene, corresponding to the shift from C3 to C4 environments, and later with the development of south‐western Africa’s winter‐rainfall regime. These shifts are not simultaneous across the region, with different geographic centres of diversity generated during different time periods.Main conclusions Regions that are prominent centres of chameleon diversification are encompassed by the current biodiversity hotspots as shown by chameleon species richness and phylogenetic diversity. Diversity within the Cape Floristic Region appears to be the result of a Late Pliocene radiation, whereas the diversity encompassed within the Maputaland–Pondoland–Albany hotspot is an aggregate of asynchronous radiation events, probably influenced by lineage losses. Overall, dwarf chameleons have experienced a shift in habitat types, with recent radiations occupying open habitats, and older lineages persisting in relictual forested habitats, corresponding to the continental shift of vegetation types since the Miocene Climatic Optimum.

The structure and harvesting potential of the sand forest in Tshanini Game Reserve, South Africa

An analysis of the size class distribution structure of the Tall and Short Sand Forest subcommunities of the Tshanini Game Reserve is presented for the first time. The study area lies south of Tembe Elephant Park within the Maputaland–Pondoland–Albany biodiversity hotspot of South Africa. A preliminary survey for distribution and abundance of hardwood tree species was conducted in both Tall and Short Sand Forest subcommunities. The data on the size class distribution were analysed at both subcommunity and species levels to classify the population structure. The population structure indicated that at the subcommunity level, the Short and Tall Sand Forest have growing populations of species, and are forests of coarse to intermediate grain respectively. At species level, four categories were distinguished, ranging in scale from an ideal to an abnormal size class distribution of the population. Most evaluated forest species indicated a growing or stable population structure. A range of species was evaluated for potential sustainable utilisation.