The value of the IUCN Red List for conservation

The IUCN Red List of Threatened Species is the most comprehensive resource detailing the global conservation status of plants and animals. The 2004 edition represents a milestone in the four-decade long history of the Red List, including the first Global Amphibian Assessment and a near doubling in assessed species since 2000. Moreover, the Red List assessment process itself has developed substantially over the past decade, extending the value of the Red List far beyond the assignation of threat status. We highlight here how the Red List, in conjunction with the comprehensive data compiled to support it and in spite of several important limitations, has become an increasingly powerful tool for conservation planning, management, monitoring and decision making.     

Using the IUCN Red List to determine effective conservation strategies

Threatened species lists continue to grow while the world’s governments fail to meet biodiversity conservation goals. Clearly, we are failing in our attempts to conserve biodiversity. Yet 37 mammal species genuinely improved in status in the 2009 IUCN Red List, suggesting there are ways to successfully conserve biodiversity. Here, I compare the threats and conservation actions (proposed and implemented) by the expert assessors of the Red List of improving species to a further 144 declining mammal species to determine whether specific threats were more easily remedied, and whether certain conservation actions were more successful than others. Declining species were faced with different threatening processes to mammals improving in status suggesting some threats were easier to treat (e.g. hunting) than others (climate change, invasive species). Declining species had different proposed and implemented conservation actions than improving species suggesting some actions are more successful than others. Threatened species were invariably found in conservation areas, suggesting protected area creation alone is not an overly successful strategy for species at risk of extinction. Conservation actions were more frequently implemented for improving than declining species suggesting active conservation is effective in improving the status of biodiversity. There were significant differences between proposed and implemented conservation actions suggesting some actions are easier to implement than others. Reintroduction, captive breeding and hunting restriction were more effective in conserving mammals than site creation and invasive species control. These findings highlight effective conservation actions for mammals worldwide and allow the rationalisation of threat mitigation measures to ensure economically justifiable biodiversity conservation strategies.     

Using species distribution models for IUCN Red Lists of threatened species

Red Lists have been used for years globally and regionally in many countries to highlight species that need special attention because of the rarity or rapid decline of their populations. To ensure homogenized classification at the global and regional level, the International Union for Conservation of Nature (IUCN) defined categories of threat, and criteria to attribute the taxa to these categories. Nevertheless, the strict application of the criteria is not always straightforward, especially for invertebrates, because of the difficulties associated with precise estimates of the size and viability of their populations. This paper presents a method for the estimation of extent of occurrence (EOO) and area of occupancy (AOO) based on species distribution models using multivariate adaptive regression splines. To achieve this, presence data have been modeled against topographical and climatic explanatory variables. Predictions from the statistical distribution models have then been cut using the minimal convex hull around (EOO) or the watersheds in which (AOO) the species have really been observed in recent years. This allows us to delimit the EOO and AOO according to the IUCN criteria, and better take into account the ecological requirements of the species. Furthermore, the method allows for the use of historical data (e.g. from museum’s collections) and the direct comparison of historical and recent distributions of species. The method has been tested on six species of butterflies. The results show the possibility of using species distribution models to define the Red Lists status according to the IUCN guidelines, and shows that the results are consistent with previous Red Lists assessments.     

Prioritizing species for conservation planning

The efforts to protect biological diversity must be prioritized because resources for nature conservation are limited. Conservation prioritization can be based on numerous criteria, from ecological integrity to species representation, but in this review I address only species-level prioritization. Criteria used for species prioritization range from aesthetical to evolutionary considerations, but I focus on the aspects that are biologically relevant. I distinguish between two main aspects of diversity that are used as objectives: Maintenance of biodiversity pattern, and maintenance of biodiversity process. I identify two additional criteria typically used in species prioritization that serve for achieving the objectives: The species’ need of protection, and cost and effectiveness of conservation actions. I discuss how these criteria could be combined with either of the objectives in a complementarity-based benefit function framework for conservation prioritization. But preserving evolutionary process versus current diversity pattern may turn out to be conflicting objectives that have to be traded-off with each other, if pursued simultaneously. Although many reasonable criteria and methods exist, species prioritization is hampered by uncertainties, most of which stem from the poor quality of data on what species exist, where they occur, and what are the costs and benefits of protecting them. Surrogate measures would be extremely useful but their performance is still largely unknown. Future challenges in species prioritization lie in finding ways to compensate for missing information.     

Application of IUCN Red Listing Criteria at the Regional and National Levels: A Case Study from Central Asia

We assessed the threatened status of 163 Central Asian vertebrates using the IUCN Red List Criteria (Version 3.1) at the national and regional levels, and compared these assessments to the global assessments given in the IUCN 2002 Red List. We thus compared threat status at three spatial scales; national for five countries separately (Kazakhstan, Kyrgyzstan, Tadjikistan, Turkmenistan, Uzbekistan), regional for the five countries together, and global. This analysis was undertaken as a test of the applicability of IUCN criteria at the sub-global level. Generally the criteria worked well. In 4% of cases, the threat category was lower at the smaller scale of assessment. This was predominately caused by the use of decline rate criteria at the larger scale when populations at the smaller scale were stable. We also encountered issues with the listing of migratory species at the sub-global level. We used our data to carry out a preliminary assessment of Protected Area coverage in the region, and found evidence suggesting that threatened species and endemics are not well covered by the current protected area system.     

Application of IUCN criteria and Red List categories to species of five Anacardiaceae genera in Madagascar

The conservation status of five genera of Anacardiaceae in Madagascarwas determined by applying IUCN risk assessment criteria to recent taxonomicrevisions and available specimen data. A major problem in establishing protocolsfor efficiently protecting and conserving Madagascar's biodiversity is the lackof essential biological information. In light of this, primary occurrence dataappears to be an invaluable tool for assessing both current and historic speciesdistributions. GIS technology was used to create species distribution maps forhistoric vs. recent occurrence data to analyze the change in conservationstatus, extent of occurrence, and area of occupancy for each of the targetspecies. A GAP analysis reveals that 14 (100%) of the target species for whichdata were available are considered threatened by IUCN standards. Furthermore, 11(79%) species showed a decrease both in the number of subpopulations and theirextent of occurrence when compared to historic distributions. This studyhighlights the importance of two factors necessary to address modernconservation questions. Sound conclusions regarding the conservation status ofindividual species requires a strong taxonomic framework and good collectiondata for a species distribution. However, because specimen data are very oftenincomplete and biased both geographically and taxonomically, reaching soundconclusions requires field knowledge of individual species to compensate forthese limitations.     

关于物种濒危等级标准之探讨--对IUCN物种濒危等级的思考

为了保存地球上的生物多样性,我们需要根据物种的种群数量与分布、种群数量波动与分布区下降速率来评定濒危物种的濒危等级,并针对物种的濒危等级提出具体的保护措施。1994年11月,IUCN第40次理事会会议正式通过了经过修订的Mace-Lande物种濒危等级标准作为IUCN物种濒危等级标准。IUCN濒危物种红色名录虽然不是国际法和国家法律,但是对于政府间组织、非政府组织的保护决策以及各国的自然法律法规的制定有着深远的影响,在保护生物学理论研究中也发挥了一定作用。我们在研究制定中国水生野生生物濒危等级标准时发现,如果直接应用IUCN物种濒危等级标准评定水生野生生物濒危等级将存在一些问题。如：(1)如何区别对待那些本来就数量稀少、分布区狭窄的物种和那些由于人类活动而导致其种群数量与生境面积急剧下降的物种?(2)不同的动物类群能否应用同一濒危标准尺度?(3)如何区别对待物种边缘分布区和核心分布区的种群数量与密度的差异?(4)如何处理种群的局部灭绝、局部濒危?(5)一些濒危物种在野生环境中濒危,但是这些物种可以人工繁殖,如何处理可以人工繁殖的濒危物种?(6)如果没有种群与栖息地的精确历史资料和统计数据,怎样应用物种的濒危标准评估其濒危等级?在实践中,我们针对这些问题提出了解决方案。考虑与国际流行的IUCN物种濒危等级标准接轨,我们提出来一个由“无危”、“值得关注”、“受胁”、“濒危”和“灭绝”等5个级构成的濒危等级系统,其中“值得关注”、“受胁”、“濒危”又分为“一般”与“高度”两个亚等级。我们提出应区分“生态濒危物种”、“进化濒危物种”;对于不同生物类群,应区分物种的生活史对策,制定不同生活史物种的濒危标准。对于r-对策物种,引入“经济灭绝”这一等级,将这一等级对应于“受胁”等级,以解决缺少物种数量的统计数据和历史数据这一难题;区别对待特有物种,将其濒危等级提升一等;引进集合种群(metapopulation)概念,将集合种群的局域种群(local population)作为“个体”对待。     

Redlistr: tools for the IUCN Red Lists of ecosystems and threatened species in R

The International Union for the Conservation of Nature (IUCN) Red List of ecosystems and Red List of threatened species are global standards for assessing risks of ecosystem collapse and species extinction. However, misconceptions of the Red List assessment process, along with its technically demanding nature, can result in the misapplication of their criteria, leading to inconsistent and potentially unreliable assessments. To address this problem, we developed redlistr, an R package aiding in the production of consistent species and ecosystem Red List assessments. Redlistr's features include methods to calculate 1) area from spatial data, 2) range size metrics, 3) rates of change of distributions or populations, and 4) distribution or population at another time from these rates. A key feature of the package is the systematic approach used to eliminate geometric uncertainty when estimating area of occupancy. Here, we develop two case studies to demonstrate the functionalities of redlistr with typical workflows for both species and ecosystems. Redlistr was developed to be accessible to users with a broad range of experience in programming for spatial and temporal data analysis, and sufficiently flexible to allow users to parameterise functions and select equations to fit their purposes. The package specifically aims to assist researchers and conservation practitioners to conduct robust and transparent risk assessments of ecosystems and species under the IUCN Red List criteria but is also useful for other studies requiring analyses of range size, area change and calculations of rates of change.     

Application to the terrestrial vertebrates of Italy of a system proposed by IUCN for a new classification of national Red List categories

The criteria for classification set down in the new system of the IUCN Red List categories were applied to national distribution areas. Application of the new criteria to national distribution areas calls for an estimate of the rate of immigration. Classification was applied to the Italian autochthonous terrestrial vertebrate species that reproduce in Italy (Amphibia, Reptilia, Aves and Mammalia). Species with both marine and land habitats were included, but Cetaceans were excluded. Eighty-eight species of the autochthonous species that reproduce in Italy were classified in the threatened categories at the national level. One of the main purposes of the present classification of the risk of extinction in national distribution areas is to provide the information needed to define global conservation priorities of species present on national territory. The species nationally and/or globally endangered or at lower risk were grouped into four priority classes, on the basis of their reproductive phenology on national territory and the size of temporarily present contingents. Of the 551 species present regularly or seasonally on Italian territory, 149 (27.0%) are in the initial indicative list of conservation priorities.     

Associations of invasive alien species and other threats to IUCN Red List species (Chordata: vertebrates)

Apart from acting synergistically or additively, threats to species may be associated or disassociated. Here we link global data on threatened Chordata species, mainly birds, mammals, and amphibians, with a probabilistic methodology to test whether the impact from invasive alien species co-occurs purely randomly, associated, or disassociated with impact from nine other major threats to biodiversity listed in the International Union for Conservation of Nature Red List database. Impacts from several of the other threats, in particular from natural disasters, are associated with the impact from invasive alien species. Three of the threats of anthropogenic origin, namely habitat loss, harvesting, and human disturbance, co-occur randomly with impact from invaders, and we suggest several explanations to this unexpected relationship, such as ambiguous evidence for associations between them and human-induced disturbances. Impact from invasive alien predators has a strong association with impact from native predators, indicating that similarity in autecology affects co-occurrences between threats. The threat from invasive predators is disassociated from intrinsic factors on islands, probably because species suffering from for instance inbreeding problems have low densities and rarely encounter invasive alien predators. The analysis of co-occurrence of impact from invasive alien species and other threats is a first step to understand and mitigate vulnerability of a community to the simultaneous exposure to invasive alien species and other threats. Association or disassociation between threats may depend on correlations between exposures and sensitivity to the threats or on the presence of one threat increasing or decreasing the sensitivity to another.     

Using long-term ornithological studies in setting targets for conservation in Britain

Long-term studies are necessary in conservation work for two main purposes: monitoring of population parameters, and defining habitat requirements to set targets for conservation action. Apart from their intrinsic interest, birds may be of value also as a means of monitoring the wider environment. Current developments include the integration of measures of breeding performance and survival with those of population size. This will also aid early warning of changes. The range of normal variation in these measures needs assessment to identify limits beyond which action is needed. Monitoring studies need to be reported in appropriate habitat or geographical units, but cover as wide a geographical area as possible in a coordinated manner, to provide context. Long-term studies are required for defining requirements, as needs may vary with overall population size, weather conditions, and other features which differ between years. Population studies based on age-structures at a moment in time may not be a good approximation of the real performance as assessed by following age-cohorts through time. This may be especially so in rare species. For these, sample sizes also present problems in short studies. Long-term studies may be required also to identify the needs of less obvious components of populations, such as immature individuals.     

The pitfall-trap of species conservation priority setting

To elucidate the factors underlying species conservation priority setting, we analysed the relationships among species’ structural complexity, scientific attention, threatened species listing, and conservation investments at different organisational levels, including global, European, national, and sub-national. Although the literature often highlights the need to consider criteria other than extinction risk status, our results show that an excessive use of Red lists still persists in the setting of conservation priorities. We found that organismal complexity, available scientific information, and species listing combine together to create a positive feed-back loop, in which more complex organisms have a larger proportion of threatened species in the Red lists and legal lists. This bias promotes research that is devoted to understanding conservation problems as well as more funds invested to solve them. We propose that a sort of pitfall-trap is currently constraining the species conservation priority setting, in which few species, mainly threatened and better-known species, tend to receive most of the funds and policy attention. To counteract this pitfall-trap, we highlight the need to increase scientific effort on lower taxa and expand Red lists to assess lesser-known taxonomic groups as well as the need to use other criteria for species conservation prioritisation.     

Applying the IUCN Red List criteria to small-sized plants on oceanic islands: conservation implications for threatened bryophytes in the Canary Islands

The International Union for Conservation of Nature (IUCN) Red List categories and criteria were applied to small-sized spore-producing plants with high dispersal capacities (bryophytes). The application of some of the IUCN criteria to bryophytes in small and highly environmental diverse islands implies several problems. The criteria applicability increases when the occupancy area is reduced. However, for common species restricted to a single type of vegetation belt, the use of the IUCN criteria is problematic because of inapplicable and/or misleading thresholds. We adapted the IUCN criteria by modifying the occupancy and occurrence area sizes and by specifying the location. This approach allowed us to establish the first Red List for the bryophyte species in the Canaries, which comprises 105 species (67 mosses and 38 liverworts); among them, 7 are critically endangered, 20 are endangered and 78 are vulnerable. Twenty-six species were classified as near-threatened, 245 were considered to be at low risk and 125 were data deficient (DD). Among the DD ones, 19 corresponded to newly reported species (DD-n) and 40 had no records during the last 30?years (DD-va). Our findings show that the freshwater habitats as well as the habitats in the most restricted cloud forests (with Erica platycodon) contain the majority of the threatened species, followed by other types of laurel forests and high mountain habitats.     

A new method for conservation planning for the persistence of multiple species

Although the aim of conservation planning is the persistence of biodiversity, current methods trade-off ecological realism at a species level in favour of including multiple species and landscape features. For conservation planning to be relevant, the impact of landscape configuration on population processes and the viability of species needs to be considered. We present a novel method for selecting reserve systems that maximize persistence across multiple species, subject to a conservation budget. We use a spatially explicit metapopulation model to estimate extinction risk, a function of the ecology of the species and the amount, quality and configuration of habitat. We compare our new method with more traditional, area-based reserve selection methods, using a ten-species case study, and find that the expected loss of species is reduced 20-fold. Unlike previous methods, we avoid designating arbitrary weightings between reserve size and configuration; rather, our method is based on population processes and is grounded in ecological theory.     

IUCN Red List assessment of the Cape Verde endemic flora: towards a global strategy for plant conservation in Macaronesia

We review the conservation status and threats to the endemic vascular flora of the Cape Verde islands, mostly based on the past two decades of collecting, literature review and herbarium specimens. The application of IUCN Red List criteria and categories using RAMAS software reveals that 78% of the endemic plants are threatened (29.3% Critically Endangered, 41.3% Endangered, 7.6% Vulnerable). Most of these endemics have a limited geographical range, and half of them have Areas of Occupancy and Extents of Occurrence of < 20 and 200 km², respectively. Our data show that, over the last two decades, the Cape Verde vascular plants have become more threatened and their conservation status has declined, mostly as a consequence of the increase in exotic species, habitat degradation and human disturbance. This paper presents the first comprehensive IUCN Red List data review for the plants endemic to Cape Verde, thus providing an important step towards the recognition and conservation of its threatened endemic flora at the national and global level. It also fills a knowledge gap, as it represents the first thorough assessment of the conservation status of the entire endemic flora of a Macaronesian archipelago.