One hundred questions of importance to the conservation of global biological diversity.

We identified 100 scientific questions that, if answered, would have the greatest impact on conservation practice and policy. Representatives from 21 international organizations, regional sections and working groups of the Society for Conservation Biology, and 12 academics, from all continents except Antarctica, compiled 2291 questions of relevance to conservation of biological diversity worldwide. The questions were gathered from 761 individuals through workshops, email requests, and discussions. Voting by email to short-list questions, followed by a 2-day workshop, was used to derive the final list of 100 questions. Most of the final questions were derived through a process of modification and combination as the workshop progressed. The questions are divided into 12 sections: ecosystem functions and services, climate change, technological change, protected areas, ecosystem management and restoration, terrestrial ecosystems, marine ecosystems, freshwater ecosystems, species management, organizational systems and processes, societal context and change, and impacts of conservation interventions. We anticipate that these questions will help identify new directions for researchers and assist funders in directing funds.

Mapping grazing-induced degradation in a semi-arid environment: a rapid and cost effective approach for assessment and monitoring.

Improved techniques for measuring and monitoring the state of biodiversity are required for reporting on national obligations to international and regional conservation institutions. Measuring the extent of grazing-related degradation in semi-arid ecosystems has proved difficult. Here we present an accurate and cost-effective method for doing this, and apply it in a South African semi-arid region that forms part of a globally significant biodiversity hotspot. We grouped structurally and functionally similar vegetation units, which were expert-mapped at the 1:50,000 scale, into four habitat types, and developed habitat-specific degradation models. We quantified degradation into three categories, using differences between dry and wet season values of the Normalized Difference Vegetation Index (NDVI) for the three succulent karoo habitats, and the difference between maximum and mean NDVI values for the subtropical thicket habitat. Field evaluation revealed an accuracy of 86%. Overall, degradation was high: 24% of the study area was modeled as severely degraded, and only 9% as intact. Levels of degradation were highest for bottomland habitats that were most exposed to grazing impacts. In sharp contrast to our methods, a widely used, broad-scale and snapshot assessment of land cover in South Africa was only 33% accurate, and it considerably underestimated the extent of severely degraded habitat in the study area. While our approach requires a multidisciplinary team, and in particular expert knowledge on the characteristics and spatial delimitation of vegetation types, it is repeatable, rapid, and relatively inexpensive. Consequently, it holds great promise for monitoring and evaluation programs in semi-arid ecosystems, in Africa, and beyond.

Integrating biosystematic data into conservation planning: perspectives from southern Africa's Succulent Karoo.

In this paper we explore the role that biosystematists can play in conservation planning. Conservation planning concerns the location and design of reserves that both represent the biodiversity of a region and enable the persistence of that biodiversity by maintaining key ecological and evolutionary processes. For conservation planning to be effective, quantitative targets are needed for the spatial components of a region that reflect evolutionary processes. Using examples from southern Africa's Succulent Karoo, we demonstrate how spatially explicit data on morphological variation within taxa provide essential information for conservation planning in that such variation represents an important surrogate for the spatial component of lineage diversification. We also provide an example of how the spatial components of evolutionary processes can be identified and targeted for conservation action. Key to this understanding are the recognition and description of taxonomic units at all spatial scales. Without the recognition of subspecific variation, it is difficult to formulate evolutionary hypotheses, let alone set quantitative targets for the conservation of this variation. Given the escalating threats to biodiversity, and the importance of planning for persistence by incorporating ecological and evolutionary processes into conservation plans, it is essential that systematists develop hypotheses on the spatial surrogates for these processes for a wide range of lineages. The important questions for systematists to be asking are (1) how is variation distributed in the landscape, and (2) how did it come about? Conservation planners too need to highlight these spatial components for conservation action.

Rapid plant diversification: planning for an evolutionary future.

Systematic conservation planning is a branch of conservation biology that seeks to identify spatially explicit options for the preservation of biodiversity. Alternative systems of conservation areas are predictions about effective ways of promoting the persistence of biodiversity; therefore, they should consider not only biodiversity pattern but also the ecological and evolutionary processes that maintain and generate species. Most research and application, however, has focused on pattern representation only. This paper outlines the development of a conservation system designed to preserve biodiversity pattern and process in the context of a rapidly changing environment. The study area is the Cape Floristic Region (CFR), a biodiversity hotspot of global significance, located in southwestern Africa. This region has experienced rapid (post-Pliocene) ecological diversification of many plant lineages; there are numerous genera with large clusters of closely related species (flocks) that have subdivided habitats at a very fine scale. The challenge is to design conservation systems that will preserve both the pattern of large numbers of species and various natural processes, including the potential for lineage turnover. We outline an approach for designing a system of conservation areas to incorporate the spatial components of the evolutionary processes that maintain and generate biodiversity in the CFR. We discuss the difficulty of assessing the requirements for pattern versus process representation in the face of ongoing threats to biodiversity, the difficulty of testing the predictions of alternative conservation systems, and the widespread need in conservation planning to incorporate and set targets for the spatial components (or surrogates) of processes.

Plant diversity in mediterranean-climate regions.

The high plant diversity of mediterranean-climate regions has attracted much attention over the past few years. This review discusses patterns and determinants of local, differential and regional plant diversity in all five regions. Local diversity shows great variation within and between regions and explanations for these patterns invoke a wide range of hypotheses. Patterns of regional diversity are the result of differential speciation and extinction rates during the Quaternary. These rates have been influenced more by the incidence of fire and the severity of climate change than by environmental heterogeneity. All regions have a high number of rare and locally endemic taxa that survive as small populations, many of which are threatened by habitat transformation.

Smoke-induced germination of succulents (Mesembryanthemaceae) from fire-prone and fire-free habitats in South Africa.

Previous studies have shown germination to be stimulated by fire-related cues such as heat and charate extract and, more recently, plant-derived smoke extract. However, smoke extract has not been tested on non-fire-prone species. We hypothesized that smoke-induced germination would be restricted to fire-prone species and investigated responses of members of the family Mesembryanthemaceae which has genera confined to fire-prone and to non-fire-prone habitats as well as genera with species across both habitats. Results of germination trials of smoke effects did not support the hypothesis. Plant-derived smoke extract stimulated germination in both fire-prone and non-fire-prone species. These results cast some doubt on the ecological significance of smoke as a fire-related cue and we suggest that investigation of effects of fire-related cues on non-fire prone species may throw light on general mechanisms of germination.

Winter growth phenology and leaf orientation in Pachypodium namaquanum (Apocynaceae) in the succulent karoo of the Richtersveld, South Africa.

Pachypodium namaquanum (Nyley ex Harb.) Welw., an unusual arborescent stem succulent from the succulent karoo of the arid Richtersveld in north-western South Africa and adjacent Namibia, is characterized by a striking curvature of the terminal 20-60 cm of the trunk toward the north. This orientation displays the single terminal whorl of drought-deciduous leaves with their flat surface angled at a mean inclination of 55° from horizontal. Inclination of 50-60° was found in 65% of individuals sampled, and 85% were inclined between 45 and 65°. Northward azimuth was also quite regular, but varied slightly between populations. The fixed leaf orientation in P. namaquanum maximizes radiation absorption during the winter months when leaves are present. Leaves normally form in early fall (April) and abscise early in spring (October). Growing season conditions in the Richtersveld are relatively mild, with mean maximum temperature dropping only to 21.6°C in July, the coldest month of the year. Frosts are rare. By the fixed orientation of its leaf whorl, P. namaquanum is able to maintain nearly twice the midwinter radiation absorptance that it would have with horizontal orientation. Over an annual cycle the angled leaves receive more radiation than would horizontal leaves for each of the 6 months in which they are present on the plant. This increased winter irradiance is hypothesized to singificantly increase net primary production by concentrating growth activities in winter months and allowing the species to remain dormant during the hyperarid conditions of the hot summer months. Midwinter flowering from apical buds in P. namaquanum may also be aided by its stem orientation. The evolution of this characteristic pattern of winter growth phenology and nodding stem orientation may have come about because of low but relatively regular autumn precipitation and moderate winter temperatures. Slow and regular growth of P. namaquanum leads to long lifespans which may reach 300 years or more.

Seed size: phylogeny and adaptation in two closely related Proteaceae species-pairs.

We studied seed size, seed nutrient status and seedling growth of two closely related fynbos Proteaceae species-pairs growing on juxtaposed soils of different nutrient and moisture status. Seeds had a greater mass and higher phosphorus and nitrogen contents for species occurring on limestone (higher nutrient and moisture contents) than those on the colluvial sands (lower nutreints and moisture). This trend was found within, but not across genera, stressing the importance of phylogeny in interpreting adaptations. It would be difficult to test for the effects of either nutrients or moisture separately, since the same advantage of enhanced seedling size, and hence survival in a stressed environment, applies to both factors. The increased root: shoot ratios (using lengths) of the Leucadendron species relative to the Protea species are interpreted as an attempt to overcome a phylogenetic constraint that results in smaller seed size in the former genus.

The occurrence of C3 and C4 grasses in fynbos and allied shrublands in the South Eastern Cape, South Africa.

There are roughly equal numbers of C3 and C4 grass species in fynbos and allied shrublands of the warm temperate coastal regions of the south eastern Cape. Subtropical-tropical C4 species have the highest relative cover in all shrubland types, particularly in renosterveld communities on moderately fertile soils. Physiological characteristics of C3 and C4 grasses predict that C3 species will be most abundant in cool, shaded sites. This prediction, and the hypothesis that relative C3 grass cover would be highest on infertile soils, were tested by correlation and regression analyses. Results show that C3 grass cover is significantly correlated with increased post-disturbance vegetation age, low intensity grazing, high litter cover and cool, steep, poleward slopes. All these factors contribute to lower growing season temperatures, favouring the competitive growth of C3 species. Amongst the soil variables, high sand content and low levels of total nitrogen emerged as predictors of high relative C3 grass cover.