Temporal biodiversity change in transformed landscapes: a southern African perspective

Landscape transformation by humans is virtually ubiquitous, with several suggestions being made that the world's biomes should now be classified according to the extent and nature of this transformation. Even those areas that are thought to have a relatively limited human footprint have experienced substantial biodiversity change. This is true of both marine and terrestrial systems of southern Africa, a region of high biodiversity and including several large conservation areas. Global change drivers have had substantial effects across many levels of the biological hierarchy as is demonstrated in this review, which focuses on terrestrial systems. Interactions among drivers, such as between climate change and invasion, and between changing fire regimes and invasion, are complicating attribution of change effects and management thereof. Likewise CO(2) fertilization is having a much larger impact on terrestrial systems than perhaps commonly acknowledged. Temporal changes in biodiversity, and the seeming failure of institutional attempts to address them, underline a growing polarization of world views, which is hampering efforts to address urgent conservation needs.     

Endemicity of Afromontane grasshopper assemblages: implications for grassland conservation

The Drakensberg escarpment in southern Africa is extensively afforested with pine plantations. The Afromontane grasslands in this area have large numbers of endemic plant taxa, but very little is known of their invertebrate fauna. We report on the microgeographical and broad‐scale geographical characteristics of grasshoppers and their allies (Orthoptera) at the Groenvaly grassland fragmentation experiment site, South Africa. Pre‐fragmentation sampling indicates that control sites and experimental fragments were comparable at the start of the experiment. Of the surveyed species (total 31 species) 25% are endemic to this grassland with another 33% occurring more widely in montane grasslands of south‐eastern South Africa. The level of orthopteran endemicity is therefore similar to that of plants, emphasizing the conservation importance of this threatened habitat. There was a significant inverse relation between the degree of stenotopy of a species within the study site and its geographical range in southern Africa, with implications for interpreting the conservation importance of taxonomically and geographically unknown taxa such as the beetles (Coleoptera) in the Afromontane grassland. This information on endemicity of the Afromontane Orthoptera indicates that these grasslands harbour a diverse endemic fauna representing a significant part of southern African biodiversity.     

Priority areas for the conservation of South African vegetation: a coarse-filter approach

Abstract.  South Africa has an important responsibility to global biodiversity conservation, but a largely inadequate conservation area network for addressing this responsibility. This study employs a coarse-filter approach based on 68 potential vegetation units to identify areas that are largely transformed, degraded or impacted upon by road-effects. The assessment highlights broad vegetation types that face high biodiversity losses currently or in the near future due to human impacts. Most vegetation types contain large tracts of natural vegetation, with little degradation, transformation or impacts from road networks. Regions in the grasslands, fynbos and forest biomes are worst affected. Very few of the vegetation types are adequately protected according to the IUCN's 10% protected area conservation target, with the fynbos and savanna biomes containing a few vegetation types that do achieve this arbitrary goal. This investigation identifies areas where limited conservation resources should be concentrated by identifying vegetation types with high levels of anthropogenic land use threats and associated current and potential biodiversity loss.     

Life After Logging: Strategic Withdrawal from the Garden of Eden or Tactical Error for Wilderness Conservation?

Conservation management has undergone a dramatic paradigm shift from the strong ‘wilderness conservation’ ethos of the 1980s and 1990s to the ‘biodiversity on degraded lands’ ethos of recent years. Most conservation biologists now consider that wilderness conservation alone is no longer sufficient to conserve biodiversity, and conservation strategies must also demand more effective protection for biodiversity on degraded lands. Recognition of this shifting paradigm in biodiversity conservation has led to an overt change in tone of recent studies, emphasizing relatively modest effects of human disturbance, and high biodiversity values on some degraded lands. A case in point is a series of studies from Southeast Asia reporting relatively modest impacts of logging on biodiversity, with the majority of species (75%) persisting after repeated intensive logging. This is a marked shift in conservation message after >30 yrs of research showing substantial adverse effects of logging on biodiversity, and raises serious questions about the appropriate ways to qualify the conflicting messages that ‘human impact degrades biodiversity’ yet ‘degraded habitats have high biodiversity value.’ Clearly logging is the lesser of two land‐use evils compared with conversion to intensive cattle pastures, crop fields or oil palm plantations, but there is a real risk that overselling the ‘biodiversity on degraded lands’ paradigm might end up being a double‐edged sword for conservation management. After all, if >75 percent of species are resilient to repeated logging, why bother trying to preserve the few remaining wilderness areas from being logged themselves? It remains to be seen whether this new message of ‘weak’ effects of logging on biodiversity will serve its strategic purpose of conserving biodiversity on degraded lands, or simply devalue the last vestiges of wild nature.     

Climate and litter quality differently modulate the effects of soil fauna on litter decomposition across biomes

Climate and litter quality have been identified as major drivers of litter decomposition at large spatial scales. However, the role played by soil fauna remains largely unknown, despite its importance for litter fragmentation and microbial activity. We synthesised litterbag studies to quantify the effect sizes of soil fauna on litter decomposition rates at the global and biome scales, and to assess how climate, litter quality and soil fauna interact to determine such rates. Soil fauna consistently enhanced litter decomposition at both global and biome scales (average increment ~ 27%). However, climate and litter quality differently modulated the effects of soil fauna on decomposition rates between biomes, from climate‐driven biomes to those where climate effects were mediated by changes in litter quality. Our results advocate for the inclusion of biome‐specific soil fauna effects on litter decomposition as a mean to reduce the unexplained variation in large‐scale decomposition models.     

Integrating theory into disturbance interaction experiments to better inform ecosystem management

Managing multiple, interacting disturbances is a key challenge to biodiversity conservation, and one that will only increase as global change drivers continue to alter disturbance regimes. Theoretical studies have highlighted the importance of a mechanistic understanding of stressor interactions for improving the prediction and management of interactive effects. However, many conservation studies are not designed or interpreted in the context of theory and instead focus on case‐specific management questions. This is a problem as it means that few studies test the relationships highlighted in theoretical models as being important for ecological management. We explore the extent of this problem among studies of interacting disturbances by reviewing recent experimental studies of the interaction between fire and grazing in terrestrial ecosystems. Interactions between fire and grazing can occur via a number of pathways; one disturbance can modify the other's likelihood, intensity or spatial distribution, or one disturbance can alter the other's impacts on individual organisms. The strength of such interactions will vary depending on disturbance attributes (e.g. size or intensity), and this variation is likely to be nonlinear. We show that few experiments testing fire–grazing interactions are able to identify the mechanistic pathway driving an observed interaction, and most are unable to detect nonlinear effects. We demonstrate how these limitations compromise the ability of experimental studies to effectively inform ecological management. We propose a series of adjustments to the design of disturbance interaction experiments that would enable tests of key theoretical pathways and provide the deeper ecological understanding necessary for effective management. Such considerations are relevant to studies of a broad range of ecological interactions and are critical to informing the management of disturbance regimes in the context of accelerating global change.     

Discovering the Brazilian bat fauna: a task for two centuries?

• 1 Brazil is the second most bat species‐rich country in the world, but the available information on the occurrence and distribution of bat species in Brazil is still heterogeneous and fragmented.
• 2 We review the occurrence and distribution of bat species in Brazil, analyse the spatial performance of inventories conducted to date and identify knowledge gaps. We also identify the main factors contributing to the recent increase in the knowledge of the Brazilian bat fauna, and make suggestions for maintaining this momentum into the near future.
• 3 We plotted record coordinates on a map, grouped them in 0.5 degrees of latitude × 0.5 degrees of longitude grid cells, and analysed records for each of the five terrestrial biomes in Brazil, and for the 1439 priority polygons for the conservation of Brazilian biodiversity.
• 4 We identified 5502 formal bat records in Brazil, indicating that less than 10% of the country is minimally surveyed, and that for nearly 60% of Brazil there is not a single record of bat species. Record coverage varies from 79% in the Atlantic Forest to 24% in Amazonia, but none of the Brazilian biomes is well surveyed for bats. Bat species have been recorded in only 15% of the priority areas for Brazilian biodiversity conservation.
• 5 If the current rate of recording bats in empty grid cells (10% every 4 years) was maintained, it would take 33 years for all cells to have a single record. If the current rate of recording ≥20 species in a grid cell (0.8% per year) was maintained, it would take 200 years for the bat fauna of Brazil to be minimally surveyed. Alarmingly, most of the data‐poor areas are at the expansion frontiers of the agro‐business, near the surrounding deforestation fronts.
• 6 We make recommendations for scientific research on bats in Brazil, to ensure the conservation of this ecologically important taxon.

     

The Great Escarpment of southern Africa: a new frontier for biodiversity exploration

The biodiversity of the 5,000 km-long Great Escarpment of southern Africa is currently poorly known, despite hosting half of the subcontinent’s centres of plant endemism and to have a rich endemic vertebrate fauna, particularly in the north-west and east. A country-based overview of endemism, data deficiencies and conservation challenges is provided, with Angola being the country in most need of Escarpment research and conservation. Given that the Escarpment provides most of the subcontinent’s fresh water, protection and restoration of Escarpment habitat providing such ecological services is urgently required. Key research needs are exhaustive biodiversity surveys, systematic studies to test refugia and migration hypotheses, and the effects of modern climate change. Such research results can then be consolidated into effective conservation planning and co-ordinated international efforts to protect the rich biodiversity of the Escarpment and the ecological services it provides.     

Adequacy of terrestrial fauna surveys for the preparation of Environmental Impact Assessments in the mining industry of Western Australia

Summary   The Western Australian Environmental Protection Authority has indicated that terrestrial fauna surveys undertaken for the purpose of preparing Environmental Impact Assessment (EIA) are providing inadequate information for decision-makers to assess development impacts on biodiversity and ecosystems. This study examined the current standard of terrestrial vertebrate fauna surveys undertaken as the basis for preparing an EIA. In the absence of a protocol to assess current standards of terrestrial fauna surveys, 'best practice' was defined and quantified through consultation with an 'expert panel'. Data from fauna surveys contained in 15 recent EIA reports from the Goldfields region of Western Australia were critically examined to determine the extent of compliance with 'best practice'. The majority of surveys performed poorly against the established criteria. A few reports addressed many of the issues comprehensively, however, at least 50% failed to mention or adequately address a high proportion of criteria considered essential, including searches of government databases, detection of rare/endangered fauna and multiseasonal sampling. All reports failed to employ sufficient trapping effort at both the biotope and landscape scales to adequately assess terrestrial vertebrate fauna biodiversity. These results indicate the need to redress minimum standards for terrestrial fauna surveys in order to meet the expectations of the EIA process.     

Biome stability predicts population structure of a southern African aridland bird species

Environments are heterogeneous in space and time, and the permeability of landscape and climatic barriers to gene flow may change over time. When barriers are present, they may start populations down the path toward speciation, but if they become permeable before the process of speciation is complete, populations may once more merge. In Southern Africa, aridland biomes play a central role in structuring the organization of biodiversity. These biomes were subject to substantial restructuring during Plio‐Pleistocene climatic fluctuations, and the imprint of this changing environment should leave genetic signatures on the species living there. Here, we investigate the role of adjacent aridland biome boundaries in structuring the genetic diversity within a widespread generalist bird, the Cape Robin‐chat (Cossypha caffra). We find evidence supporting a central role for aridland biomes in structuring populations across Southern Africa. Our findings support a scenario wherein populations were isolated in different biome refugia, due to separation by the exceptionally arid Nama Karoo biome. This biome barrier may have arisen through a combination of habitat instability and environmental unsuitability, and was highly unstable throughout the Plio‐Pleistocene. However, we also recovered a pattern of extensive contemporary gene flow and admixture across the Nama Karoo, potentially driven by the establishment of homesteads over the past 200 years. Thus, the barrier has become permeable, and populations are currently merging. This represents an instance where initial formation of a barrier to gene flow enabled population differentiation, with subsequent gene flow and the merging of populations after the barrier became permeable.     

The antiquity of Madagascar’s grasslands and the rise of C4 grassy biomes

Aim Grasslands and savannas, which make up > 75% of Madagascar’s land area, have long been viewed as anthropogenically derived after people settled on the island c. 2 ka. We investigated this hypothesis and an alternative – that the grasslands are an insular example of the post‐Miocene spread of C₄ grassy biomes world‐wide. Location Madagascar, southern Africa, East Africa. Methods We compared the number of C₄ grass genera in Madagascar with that in southern and south‐central African floras. If the grasslands are recent we would expect to find fewer species and genera in Madagascar relative to Africa and for these species and genera to have very wide distribution ranges in Madagascar. Secondly, we searched Madagascan floras for the presence of endemic plant species or genera restricted to grasslands. We also searched for evidence of a grassland specialist fauna with species endemic to Madagascar. Plant and animal species endemic to C₄ grassy biomes would not be expected if these are of recent origin. Results Madagascar has c. 88 C₄ grass genera, including six endemic genera. Excluding African genera with only one or two species, Madagascar has 86.6% of southern Africa’s and 89.4% of south‐central Africa’s grass genera. C₄ grass species make up c. 4% of the flora of both Madagascar and southern Africa and species : genus ratios are similar (4.3 and 5.1, respectively). Turnover of grasses along geographical gradients follows similar patterns to those in South Africa, with Andropogoneae dominating in mesic biomes and Chlorideae in semi‐arid grassy biomes. At least 16 monocot genera have grassland members, many of which are endemic to Madagascar. Woody species in frequently burnt savannas include both Madagascan endemics and African species. A different woody flora, mostly endemic, occurs in less frequently burnt grasslands in the central highlands, filling a similar successional niche to montane C₄ grasslands in Africa. Diverse vertebrate and invertebrate lineages have grassland specialists, including many endemic to Madagascar (e.g. termites, ants, lizards, snakes, birds and mammals). Grassland use of the extinct fauna is poorly known but carbon isotope analysis indicates that a hippo, two giant tortoises and one extinct lemur ate C₄ or CAM (crassulacean acid metabolism) plants. Main conclusions The diversity of C₄ grass lineages in Madagascar relative to that in Africa, and the presence of plant and animal species endemic to Madagascan grassy biomes, does not fit the view that these grasslands are anthropogenically derived. We suggest that grasslands invaded Madagascar after the late Miocene, part of the world‐wide expansion of C₄ grassy biomes. Madagascar provides an interesting test case for biogeographical analysis of how these novel biomes assembled, and the sources of the flora and fauna that now occupy them. A necessary part of such an analysis would be to establish the pre‐settlement extent of the C₄ grassy biomes. Carbon isotope analysis of soil organic matter would be a feasible method for doing this.     

Data gaps in anthropogenically driven local‐scale species richness change studies across the Earth's terrestrial biomes

There have been numerous attempts to synthesize the results of local‐scale biodiversity change studies, yet several geographic data gaps exist. These data gaps have hindered ecologist's ability to make strong conclusions about how local‐scale species richness is changing around the globe. Research on four of the major drivers of global change is unevenly distributed across the Earth's biomes. Here, we use a dataset of 638 anthropogenically driven species richness change studies to identify where data gaps exist across the Earth's terrestrial biomes based on land area, future change in drivers, and the impact of drivers on biodiversity, and make recommendations for where future studies should focus their efforts. Across all drivers of change, the temperate broadleaf and mixed forests and the tropical moist broadleaf forests are the best studied. The biome–driver combinations we have identified as most critical in terms of where local‐scale species richness change studies are lacking include the following: land‐use change studies in tropical and temperate coniferous forests, species invasion and nutrient addition studies in the boreal forest, and warming studies in the boreal forest and tropics. Gaining more information on the local‐scale effects of the specific human drivers of change in these biomes will allow for better predictions of how human activity impacts species richness around the globe.     

Review of the ecology of Australian urban fauna: A focus on spatially explicit processes

Abstract Cities have a major impact on Australian landscapes, especially in coastal regions, to the detriment of native biodiversity. Areas suitable for urban development often coincide with those areas that support high levels of species diversity and endemism. However, there is a paucity of reliable information available to guide urban conservation planning and management, especially regarding the trade‐off between investing in protecting and restoring habitat at the landscape level, and investing in programmes to maintain the condition of remnant vegetation at the local (site) level. We review the literature on Australian urban ecology, focusing on urban terrestrial and aquatic vertebrate and invertebrate fauna. We identify four main factors limiting our knowledge of urban fauna: (i) a lack of studies focusing at multiple ecological levels; (ii) a lack of multispecies studies; (iii) an almost total absence of long‐term (temporal) studies; and (iv) a need for stronger integration of research outcomes into urban conservation planning and management. We present a set of key principles for the development of a spatially explicit, long‐term approach to urban fauna research. This requires an understanding of the importance of local‐level habitat quality and condition relative to the composition, configuration and connectivity of habitats within the larger urban landscape. These principles will ultimately strengthen urban fauna management and conservation planning by enabling us to prioritize and allocate limited financial resources to maximize the conservation return.     

Lack of adequate taxonomic knowledge may hinder endemic mammal conservation in the Brazilian Atlantic Forest

The Atlantic Forest is one of the most diverse and threatened ecosystems of the world, being thus classified as one of the most important biodiversity hotspots. However, habitat loss, overexploitation, alien species, disease and pollution are not the only threats faced by native fauna and flora. The lack of adequate taxonomic knowledge hinders conservation and management efforts of endemic species. This is true even for mammals, which is the most charismatic group of animals and traditionally receive a good deal of attention from scientists and the public in general. A few examples show how this gap in local fauna information can be demise for species conservation, even misguiding management strategies: molecular data reveal a hidden marsupial diversity; the lack of taxonomic studies at the species level seriously threatens rodent conservation; and the taxonomic rearrangement of the genusBrachyteles revealed a new species and had a great impact on management strategies. New species are discovered, described and taxonomically rearranged at an astounding rate. We can only be successful in biodiversity conservation if we have at least a minimum level of knowledge about what we are trying to preserve. That is true both for researchers and for the general public. Recent taxonomic revisions may represent the turning point in Neotropical fauna knowledge, which, coupled with a greater awareness of local people about the rich biodiversity that dot their backyards, can represent a better conservation prospect for the endemics of the Atlantic Forest.     

Cattle grazing does not reduce fire severity in eucalypt forests and woodlands of the Australian Alps

Large grazing herbivores can change fire regimes by altering fuel types and abundance, particularly in savanna biomes where the dominant fuel is grass. The use of herbivores as a fire management tool is receiving increasing consideration globally, but this intervention has a limited evidence‐base and is controversial because of potential deleterious ecological effects. These issues are well illustrated by the political and scientific debate about the capacity of cattle grazing to reduce fire hazard in the Victorian Alps of Australia; there have been remarkably few scientific studies to illuminate this issue. Here we use remote sensing and geographic information system analysis to determine the effect of active grazing licences on fire severity (crown scorch) in eucalypt forests and woodlands following large fires in the Alps during the summers of 2002/2003 and 2006/2007. Our statistical analyses, which controlled for spatial autocorrelation, found crown scorch was strongly related to vegetation type but there was no evidence that cattle grazing reduced fire severity. There was some evidence that grazing could increase fire severity by possibly changing fuel arrays. Such landscape analyses are a critical approach given that large‐scale grazing × fire trials are prohibitively expensive and impractical to conduct.     

Poor historical data drive conservation complacency: The case of mammal decline in south‐eastern Australian forests

Forested ecosystems of south‐eastern Australia now differ physically, compositionally and functionally from their condition prior to European settlement. Understanding these changes, and how native species and entire ecosystems have responded, is crucial for biodiversity conservation and ecosystem management. Here I argue that a combination of limited historical information and a knowledge base biased towards modern ecological studies has resulted in a distorted perception of ecosystem condition, hindering the instigation of effective biodiversity conservation measures. This argument is based on recently obtained information about changes to the non‐volant mammal community, which reveals relatively recent but underreported ecological changes, including major declines in species distribution and abundance, shifts in niche utilization and associated disruption of ecosystem functions. Ultimately, many mammal species are being denied the capacity to function to the extent they did historically. Following this re‐assessment, it is evident that current forest management does not adequately address contemporary conservation dilemmas posed by detrimental ecosystem changes. This is especially salient when most of the factors responsible for causing changes to the mammal community are still active and include forest management and utilization activities. Therefore, additional conservation measures are essential to meet forest stewardship and biodiversity conservation obligations. For the health, functionality and sustainability of forested ecosystems, native mammal species must be capable of functioning to their ecological potential and occupy their original niche. This will be facilitated by the suppression of threatening processes (primarily exotic species), ensuring ecologically sensitive fire regimes and the reintroduction/translocation of missing species. The recovery or restoration of forest functionality based on mammal conservation should have wide‐scale benefits for biodiversity conservation.     

Cotton expansion and biodiversity loss in African savannahs, opportunities and challenges for conservation agriculture: a review paper based on two case studies

We review agricultural impacts on biodiversity and the potential of conservation agriculture in developing productive and environment-friendly cropping systems. We then analyse experiences from two African landscapes of global importance for conservation: the Mid Zambezi Valley in Southern Africa and the periphery of the “W-Arly-Penjari” complex in West Africa. In both areas, expansion of cotton farming, considered as one of the most polluting forms of agriculture in the world, drives major land use change and loss of biodiversity. In both areas, various forms of conservation agriculture have been developed and tested. We highlight the potential benefit of conservation agriculture in controlling negative environmental effects traditionally associated with agriculture and reducing the need for land conversion through increased biophysical resource use efficiency, turning agriculture from a threat to an opportunity for conservation. Finally, we raise a number of issues that constitute challenges for the widespread adoption of these technologies by resource-poor farmers, and formulate recommendations for the development, evaluation and diffusion of conservation agriculture technologies for smallholders in semi-arid Africa.     

Threatened mammals become more predatory after small‐scale prescribed fires in a high‐rainfall rocky savanna

Understanding mechanisms underlying fire regime effects on savanna fauna is difficult because of a wide range of possible trophic interactions and feedbacks. Yet, understanding mechanisms underlying fauna dynamics is crucial for conservation management of threatened species. Small savanna mammals in northern Australia are currently undergoing widespread declines and regional extinctions partly attributable to fire regimes. This study investigates mammal trophic and ecosystem responses to fire in order to identify possible mechanisms underlying these declines. Mammal trophic responses to fire were investigated by surveying mammal abundance, mammal diet, vegetation structure and non‐mammal fauna dynamics in savannas six times at eight sites over a period of 3 years. Known site‐specific fire history was used to test for trophic responses to post‐fire interval and fire frequency. Mammal and non‐mammal fauna showed only minor responses of post‐fire interval and no effect of fire frequency. Lack of fauna responses differed from large post‐fire vegetation responses. Dietary analysis showed that two mammal species, Dasyurus hallucatus and Isoodon auratus, increased their intake of large prey groups in recently burnt, compared to longer unburnt vegetation. This suggests a fire‐related change in trophic interactions among predators and their prey, after removal of ground‐layer vegetation. No evidence was found for other changes in food resource uptake by mammals after fire. These data provide support for a fire‐related top‐down ecosystem response among savanna mammals, rather than a bottom‐up resource limitation response. Future studies need to investigate fire responses among other predators, including introduced cats and dingoes, to determine their roles in fire‐related mammal declines in savannas of northern Australia.     

Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region

The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (approximately 280 000km2), and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil. We analyzed the distribution pattern of 82 genera distributed in four orders of aquatic insects (Diptera, Odonata, Ephemeroptera and Trichoptera) in Southern Brazil wetlands. Therefore, 32 biogeographic nodes corresponded to the priority areas for conservation of the aquatic insect diversity. Among this total, 13 were located in the Atlantic Rainforest, 16 in the Pampa and three amongst both biomes. The distribution of nodes showed that only 15% of the dispersion centers of insects were inserted in conservation units. The four priority areas pointed by node cluster criterion must be considered in further inclusions of areas for biodiversity conservation in Southern Brazil wetlands, since such areas present species from different ancestral biota. The inclusion of such areas into the conservation units would be a strong way to conserve the aquatic biodiversity in this region.