Identifying spatial components of ecological and evolutionary processes for regional conservation planning in the Cape Floristic Region, South Africa

Abstract. Conservation seeks ultimately to protect and maintain biodiversity indefinitely. Most biodiversity features targeted in past conservation planning have been largely aspects of ecological and biogeographical pattern rather than process. However, the persistence of biodiversity can only be ensured through consideration of the ecological and evolutionary processes that underpin biodiversity, as well as its present spatial pattern. This paper identifies spatial surrogates of ecological and evolutionary processes for regional conservation planning in one of the world's biodiversity hotspots, the Cape Floristic Region. We identified six types of spatial components (namely edaphic interfaces, upland–lowland interfaces, sand movement corridors, riverine corridors, upland–lowland gradients and macroclimatic gradients) as surrogates for key processes such as ecological and geographical diversification, and species migration. Spatial components were identified in a GIS using published data and expert knowledge. Options for achieving targets for process components have been seriously compromised by habitat transformation. Between 30 and 75% of the original extent of the spatial components currently remain functional. Options for achieving upland–lowland and macroclimatic gradients are very limited in the lowlands where most of the habitat has been transformed by agriculture. We recommend that future studies place their research on ecological and evolutionary processes in a spatially explicit framework. Areas maintaining adaptive diversification (e.g. environmental gradients, ecotones) or containing historically isolated populations should be identified and protected. The spatial dimensions of eco-logical processes such as drought and fire refugia also need to be determined and such insights incorporated in conservation planning. Finally, connectivity within these areas should be ensured to maintain species migration and gene flow.     

Conservation planning in a changing world

Conservation planning is the process of locating, configuring, implementing and maintaining areas that are managed to promote the persistence of biodiversity and other natural values. Conservation planning is inherently spatial. The science behind it has solved important spatial problems and increasingly influenced practice. To be effective, however, conservation planning must deal better with two types of change. First, biodiversity is not static in time or space but generated and maintained by natural processes. Second, humans are altering the planet in diverse ways at ever faster rates.     

Scale‐dependent complementarity of climatic velocity and environmental diversity for identifying priority areas for conservation under climate change

As most regions of the earth transition to altered climatic conditions, new methods are needed to identify refugia and other areas whose conservation would facilitate persistence of biodiversity under climate change. We compared several common approaches to conservation planning focused on climate resilience over a broad range of ecological settings across North America and evaluated how commonalities in the priority areas identified by different methods varied with regional context and spatial scale. Our results indicate that priority areas based on different environmental diversity metrics differed substantially from each other and from priorities based on spatiotemporal metrics such as climatic velocity. Refugia identified by diversity or velocity metrics were not strongly associated with the current protected area system, suggesting the need for additional conservation measures including protection of refugia. Despite the inherent uncertainties in predicting future climate, we found that variation among climatic velocities derived from different general circulation models and emissions pathways was less than the variation among the suite of environmental diversity metrics. To address uncertainty created by this variation, planners can combine priorities identified by alternative metrics at a single resolution and downweight areas of high variation between metrics. Alternately, coarse‐resolution velocity metrics can be combined with fine‐resolution diversity metrics in order to leverage the respective strengths of the two groups of metrics as tools for identification of potential macro‐ and microrefugia that in combination maximize both transient and long‐term resilience to climate change. Planners should compare and integrate approaches that span a range of model complexity and spatial scale to match the range of ecological and physical processes influencing persistence of biodiversity and identify a conservation network resilient to threats operating at multiple scales.     

Persistence and vulnerability: Retaining biodiversity in the landscape and in protected areas

An objective of biodiversity conservation activities is to minimize the exposure of biodiversity features to threatening processes and to ensure, as far as possible, that biodiversity persists in the landscape. We discuss how issues of vulnerability and persistence can and should be addressed at all stages of the conservation planning and implementation process. Procedures for estimating the likelihood of persistence and for measuring degrees of vulnerability at different spatial and temporal scales using subjective assessments, rules of thumb and analytical and simulation models are reviewed. The application of information on vulnerability and persistence to conservation planning and management is discussed under the headings of natural dynamics, replication of protection, levels of representation, source and sink population structures, refuges and critical resources, reserve design, habitat fragmentation and levels of management.     

Making evolutionary history count: biodiversity planning for coral reef fishes and the conservation of evolutionary processes

Anthropogenic activities are having devastating impacts on marine systems with numerous knock-on effects on trophic functioning, species interactions and an accelerated loss of biodiversity. Establishing conservation areas can not only protect biodiversity, but also confer resilience against changes to coral reefs and their inhabitants. Planning for protection and conservation in marine systems is complex, but usually focuses on maintaining levels of biodiversity and protecting special and unique landscape features while avoiding negative impacts to socio-economic benefits. Conversely, the integration of evolutionary processes that have shaped extant species assemblages is rarely taken into account. However, it is as important to protect processes as it is to protect patterns for maintaining the evolutionary trajectories of populations and species. This review focuses on different approaches for integrating genetic analyses, such as phylogenetic diversity, phylogeography and the delineation of management units, temporal and spatial monitoring of genetic diversity and quantification of adaptive variation for protecting evolutionary resilience, into marine spatial planning, specifically for coral reef fishes. Many of these concepts are not yet readily applied to coral reef fish studies, but this synthesis highlights their potential and the importance of including historical processes into systematic biodiversity planning for conserving not only extant, but also future, biodiversity and its evolutionary potential.     

Incorporating evolutionary processes into conservation planning using species distribution data: a case study with the western Mediterranean herpetofauna

Aim To incorporate evolutionary processes into conservation planning using species distribution patterns and environmental gradients as surrogates for genetic diversity. Location Western Mediterranean Basin. Methods Distributions of 154 herpetological species were predicted using maximum entropy models, and groups of significantly co‐occurring species (biotic elements) were identified. Environmental gradients were characterized for the complete area and for the area covered by each biotic element, by performing a principal component analysis on the data matrix composed of nine environmental variables. The first two principal component analysis axes were classified into four categories each, and those categories were combined with each other resulting in an environmental classification with 16 categories. To identify priority conservation areas, biotic elements and environmental categories were used as surrogates for the neutral and adaptive components of genetic diversity, respectively. Priority areas for conservation were identified under three scenarios: (1) setting targets for species only; (2) setting targets for species and for each environmental category of the overall area; and (3) setting targets for each species and for each environmental category within each biotic element. Results Nine biotic elements were identified – four for the amphibians and five for the reptiles. Priority areas identified in the three scenarios were similar in terms of amount of area selected, but exhibited low spatial agreement. Main conclusions Prioritization exercises that integrate surrogates for evolutionary processes can deliver spatial priorities that are fairly different to those where only species representation is considered. While new methods are emerging to incorporate molecular data in conservation prioritization, it is unlikely to be enough data for enough taxa for this to be feasible in many regions. We develop an approach using surrogates for both the neutral and adaptive components of genetic diversity that may enhance biodiversity persistence and representation when molecular data are not available or geographically comprehensive.     

How well are biodiversity drivers reflected in protected areas? A representativeness assessment of the geohistorical gradients that shaped endemic flora in Japan

Protected areas function as a lifeboat that can preserve the origins and maintenance of biodiversity. We assessed the representativeness of biodiversity in existing protected areas in Japan using a distribution dataset and phylogenetic tree for 5565 Japanese vascular plant species. We first examined the overlap of species distribution with the existing protected areas and identified the minimum set representing all plant species. Second, we evaluated the relative importance of environmental variables in explaining the spatial arrangement of protected areas using a random forest model. Finally, we clarified how potential drivers of plant diversity were sufficiently captured within the protected areas network. Although the protected areas captured the majority of species, nearly half of the minimum set areas were selected from outside the existing protected areas. The locations of existing protected areas are mainly associated with geographical and socio-economic factors rather than key biodiversity features (including evolutionary distinctiveness). Moreover, critical biodiversity drivers, which include current climate, paleoclimatic stability, and geographical isolation, were biasedly emulated within the existing protected areas. These findings demonstrate that current conservation planning fails to represent the ecological and evolutionary processes relevant to species sorting, dispersal limitation, and allopatric speciation. In particular, under-representativeness of historically stable habitats that function as evolutionary hotspots or refugia in response to climate changes may pose a threat to the long-term persistence of Japan’s endemic biota. This study provides a fundamental basis for developing prioritization measures to retain species assembly processes and in situ diversification along current climatic and geohistorical gradients.     

Geostatistical modelling of regional bird species richness: exploring environmental proxies for conservation purpose

Identifying spatial patterns in species diversity represents an essential task to be accounted for when establishing conservation strategies or monitoring programs. Predicting patterns of species richness by a model-based approach has recently been recognised as a significant component of conservation planning. Finding those environmental predictors which are related to these patterns is crucial since they may represent surrogates of biodiversity, indicating in a fast and cheap way the spatial location of biodiversity hotspots and, consequently, where conservation efforts should be addressed. Predictive models based on classical multiple linear regression or generalised linear models crowded the recent ecological literature. However, very often, problems related with spatial autocorrelation in observed data were not adequately considered. Here, a spatially-explicit data-set on birds presence and distribution across the whole Tuscany region was analysed. Species richness was calculated within 1 × 1 km grid cells and 10 environmental predictors (e.g. altitude, habitat diversity and satellite-derived landscape heterogeneity indices) were included in the analysis. Integrating spatial components of variation with predictive ecological factors, i.e. using geostatistical models, a general model of bird species richness was developed and used to obtain predictive regional maps of bird diversity hotspots. A meaningful subset of environmental predictors, namely habitat productivity, habitat heterogeneity, combined with topographic and geographic information, were included in the final geostatistical model. Conservation strategies based on the predicted hotspots as well as directions for increasing sampling effort efficiency could be extrapolated by the proposed model.     

Ecosystem Services and Opportunity Costs Shift Spatial Priorities for Conserving Forest Biodiversity

Inclusion of spatially explicit information on ecosystem services in conservation planning is a fairly new practice. This study analyses how the incorporation of ecosystem services as conservation features can affect conservation of forest biodiversity and how different opportunity cost constraints can change spatial priorities for conservation. We created spatially explicit cost-effective conservation scenarios for 59 forest biodiversity features and five ecosystem services in the county of Telemark (Norway) with the help of the heuristic optimisation planning software, Marxan with Zones. We combined a mix of conservation instruments where forestry is either completely (non-use zone) or partially restricted (partial use zone). Opportunity costs were measured in terms of foregone timber harvest, an important provisioning service in Telemark. Including a number of ecosystem services shifted priority conservation sites compared to a case where only biodiversity was considered, and increased the area of both the partial (+36.2%) and the non-use zone (+3.2%). Furthermore, opportunity costs increased (+6.6%), which suggests that ecosystem services may not be a side-benefit of biodiversity conservation in this area. Opportunity cost levels were systematically changed to analyse their effect on spatial conservation priorities. Conservation of biodiversity and ecosystem services trades off against timber harvest. Currently designated nature reserves and landscape protection areas achieve a very low proportion (9.1%) of the conservation targets we set in our scenario, which illustrates the high importance given to timber production at present. A trade-off curve indicated that large marginal increases in conservation target achievement are possible when the budget for conservation is increased. Forty percent of the maximum hypothetical opportunity costs would yield an average conservation target achievement of 79%.     

景观遗传学：概念与方法

全球变化下的物种栖息地丧失和破碎化给生物多样性保护带来了新的问题和挑战,生物多样性保护必须由单纯的物种保护上升到栖息地景观的保护。景观遗传学是定量确定栖息地景观特征对种群遗传结构影响的一门交叉学科,在生物保护及自然保护区管理方面有巨大的潜力。从生物多样性保护的角度评述了景观结构与遗传多样性的关系,介绍了景观遗传学的基本概念,研究尺度和方法,并对景观遗传学当前的研究焦点及面临的挑战做了总结。     

Toward a conceptual synthesis for climate change responses

Aim To identify hypotheses for how climate change affects long‐term population persistence that can be used as a framework for future syntheses of ecological responses to climate change. Location Global. Methods We surveyed ecological and evolutionary concepts related to how a changing climate might alter population persistence. We organized established concepts into a two‐stage framework that relates abiotic change to population persistence via changes in the rates or outcomes of ecological and evolutionary processes. We surveyed reviews of climate change responses, and evaluated patterns in light of our conceptual framework. Results We classified hypotheses for population responses to climate change as one of two types: (1) hypotheses that relate rates of ecological and evolutionary processes (plasticity, dispersal, population growth and evolution) to abiotic change, and (2) hypotheses that relate changes in these processes to four fundamental population‐level responses (colonization, acclimatization, adaptation or extinction). We found that a disproportionate emphasis on response in the climate change literature is difficult to reconcile with ecological and evolutionary theories that emphasize processes. We discuss a set of 24 hypotheses that represent gaps in the literature that limit our ability determine whether observed climate change responses are sufficient to facilitate persistence through future climate change. Main conclusions Though theory relates environmental change to fundamental ecological and evolutionary processes and population‐level responses, clear hypotheses based on theory have not been systematically formulated and tested in the context of climate change. Stronger links between basic theory and observed impacts of climate change are required to assess which responses are common, likely or able to facilitate population persistence despite ongoing environmental change. We anticipate that a hypothesis‐testing framework will reveal that indirect effects of climate change responses are more pervasive than previously thought and related to a few general processes, even though the patterns they create are incredibly diverse.     

Planning for the restoration of native biodiversity within the Goulburn Broken Catchment, Victoria, using spatial modelling

Summary   Conservation planning aims to ensure the protection and continuation of biodiversity. In rural landscapes in Victoria, this will require the restoration of habitat and biophysical processes to levels that can sustain the majority of species. Planning is required at scales large enough to have ecological relevance. In this study, a land-use change scenario that plans for the conservation of native biodiversity within the Goulburn Broken Catchment was developed using simple ecological principles. A set of indicative rules for restoring remnant native vegetation was modelled within a geographical information system. The modelling of the rules resulted in a change in rural landscapes from highly fragmented (with few large remnants) to highly connected. Future applications of this approach include incorporating the biodiversity rules into a biophysical model to assess the effect of planning landscapes for the conservation of biodiversity on hydrological and economic outcomes for the region. In addition, the rules are to be refined so that the priority landscapes for biodiversity planning can be identified.     

Large-scale plant conservation in European semi-natural grasslands: a population genetic perspective

During the last century, unprecedented landscape fragmentation has severely affected many plant species occurring in once widespread semi-natural grasslands in Europe. Fragmentation reduces population size and increases isolation, which can jeopardize the persistence of populations. Recent large-scale ecological and genetic studies across several European countries indicate that fragmented populations of common plant species exhibit a strong genetic differentiation and local adaptation to their home sites, reducing their capacity to establish new populations elsewhere. We discuss the main genetic processes that determine the performance of plant populations in severely fragmented landscapes: namely inbreeding depression, genetic differentiation and genetic introgression. We stress the need for large-scale genetic studies to detect the geographical structure of genetic variation of fragmented plant populations, since nuclei of genetically independent groups of populations may become important targets of conservation. A thorough knowledge on the large-scale geographical structure of genetic variation for a sufficiently wide array of plant species can provide the basis to develop comprehensive conservation plans to preserve the ecological and evolutionary processes that generate and maintain biodiversity of fragmented semi-natural grasslands.     

Strategies to protect biological diversity and the evolutionary processes that sustain it

Conservation planning has tended to focus more on pattern (representation) than process (persistence) and, for the former, has emphasized species and ecosystem or community diversity over genetic diversity. Here I consider how best to incorporate knowledge of evolutionary processes and the distribution of genetic diversity into conservation planning and priority setting for populations within species and for biogeographic areas within regions. Separation of genetic diversity into two dimensions, one concerned with adaptive variation and the other with neutral divergence caused by isolation, highlights different evolutionary processes and suggests alternative strategies for conservation. Planning for both species and areas should emphasize protection of historically isolated lineages (Evolutionarily Significant Units) because these cannot be recovered. By contrast, adaptive features may best be protected by maintaining the context for selection, heterogeneous landscapes, and viable populations, rather than protecting specific phenotypes. A useful strategy may be to (1) identify areas that are important to represent species and (vicariant) genetic diversity and (2) maximize within these areas the protection of contiguous environmental gradients across which selection and migration can interact to maintain population viability and (adaptive) genetic diversity. These concepts are illustrated with recent results from analysis of a rainforest fauna from northeast Australia.     

Spatial mismatches between plant biodiversity facets and evolutionary legacy in the vicinity of a major Mediterranean city

The analyses of congruencies among biodiversity components address the issue of conservation priorities, but previously they have been done at coarse scales with limited relevance for conservation actions. Moreover, these former studies consider only the species level components of biodiversity and not the intra-specific evolutionary legacy that influences future biodiversity. This study represents the first assessment of congruencies between various components of plant biodiversity and the evolutionary legacy of a narrow endemic taxon (Arenaria provincialis, Caryophyllaceae). Assessment is conducted in the vicinity of a Mediterranean big city (Marseille, S.E. France) where habitats and flora are threatened by mass tourism and urban sprawl. Our analyses reveal that the different plant biodiversity facets assessed are spatially mismatched and unequally protected. Moreover, by using only species-level components of biodiversity as conservation targets we ignore crucial areas for the evolutionary legacy of this narrow endemic plant. Our results highlight the crucial role of phylogeography as a criterion to target the genetic precursors of future biodiversity in conservation planning.     

Designing criteria suites to identify discrete and networked sites of high value across manifestations of biodiversity

Suites of criteria specifying ecological, biological, social, economic, and governance properties enable the systematic identification of sites and networks of high biodiversity value, and can support balancing ecological and socioeconomic objectives of biodiversity conservation in terrestrial and marine spatial planning. We describe designs of suites of ecological, governance and socioeconomic criteria to comprehensively cover manifestations of biodiversity, from genotypes to biomes; compensate for taxonomic and spatial gaps in available datasets; balance biases resulting from conventionally-employed narrow criteria suites focusing on rare, endemic and threatened species; plan for climate change effects on biodiversity; and optimize the ecological and administrative networking of sites. Representativeness, replication, ecological connectivity, size, and refugia are identified as minimum ecological properties of site networks. Through inclusion of a criterion for phylogenetic distinctiveness, criteria suites identify sites important for maintaining evolutionary processes. Criteria for focal species are needed to overcome data gaps and address limitations in knowledge of factors responsible for maintaining ecosystem integrity.     

Using a goal programming approach to design and evaluate protected areas for the conservation of multiple dimensions of biodiversity

The decline and loss of biodiversity provoked by human activities have caused ecologists and conservationists to center their attention on the design of conservation priority areas (PAs), focusing mainly on species conservation in terms of richness, rarity and/or vulnerability. However, biodiversity has multiple dimensions, evolutionary processes have recently been labeled the ‘missing component’ of conservation strategies, and increasingly more authors are suggesting that the ecological, evolutionary and historical aspects of biodiversity are key components of conservation planning. In this study we develop a prioritization system to design conservation PAs using the wild terrestrial mammals of the Iberian Peninsula as an example. We aim to contribute to the design of more suitable PAs by integrating ecological components of biodiversity (species richness, vulnerability and rarity), evolutionary aspects (accumulated genetic diversification) and historical information relevant to the study area. After selecting a set of biodiversity indicators, we applied a multi-objective technique (extended goal programming) to construct a combined index, where values in the top 90th percentile were then used to select the PAs. According to our most efficient and satisfactory results, some areas highlighted for their conservation are currently categorized as PAs, however, we found that it would be necessary to reconsider their extent, especially in northern Spain, where the historical aspects of biodiversity (the missing component) are more widely present. The need to determine PAs is unquestionable. However, it should also be a priority to move towards a model of sustainable and fair development.     

系统保护规划的理论、方法及关键问题

为了减缓生物多样性丧失的趋势、将有限的保护资源用于关键区域,Margules等提出了系统保护规划(Systematic Conservation Planning)概念和方法,目前该方法已成为国际主流保护规划方法。与传统基于专家决策的保护体系规划方法不同,系统保护规划拥有量化的保护目标、保护成本,并综合考虑保护体系连通性、人为干扰因素,使用优化算法计算,从而获得空间明晰的生物多样性保护体系。在阐述规划理念、规划流程与方法的基础上,重点评述了生物多样性替代指标的选择、保护规划成本的计算、保护目标的设置、规划结果的可靠性评估等关键问题,并结合我国的具体情况,探讨了该方法在我国的应用前景,以期为推进我国生物多样性与生态服务功能的保护做出贡献。     

Floristic composition in relation to environmental gradients across KwaZulu‐Natal,South Africa

Conservation planning in the face of global change is still in its infancy. A suggested approach is to incorporate environmental gradients into conservation planning as they reflect the ecological and evolutionary processes generating and maintaining diversity. Our study provides a framework to identify the dominant environmental gradients determining floristic composition and pattern. Nonmetric multidimensional scaling was used on 2155 sampling plots in savanna and grassland habitat located across the province of KwaZulu‐Natal, South Africa (94 697 km²), a floristically rich region having steep environmental gradients, to determine the dominant gradients. Hierarchical cluster analysis was used to group similar plots which were then used in a Classification and Regression Tree analysis to determine the environmental delimiters of the identified vegetation clusters. Temperature‐related variables were the strongest delimiters of floristic composition across the province, in particular mean annual temperature. Frost duration was the primary variable in the Classification and Regression Tree analysis with important implications for savanna/grassland dynamics. Soil properties (base, pH status) and moisture variables accounted for most of the variation for the second and third axes of floristic variation. Given that climatic and edaphic variables were well correlated with floristic composition, it is anticipated that a changing climate will have a marked influence on floristic composition. We predict warmer temperatures may facilitate the spread of frost sensitive savanna species into previously cooler, grassland areas. Species associated with specific soil types will not easily be able to move up the altitudinal gradient to cooler climes because geology is aligned in an approximately north‐south direction compared with increasing altitude from east‐west. Future conservation planning should take cognisance of these gradients which are surrogates for ecological and evolutionary processes promoting persistence.