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Literature ReviewStrengths and Limitations of Using the IUCN Red List for Setting Conservation Priorities Abstract This paper discusses the strengths and weaknesses of the IUCN Red List for setting conservation priorities. It discusses their strength as a systematic conservation assessment tool and draws on recent scientific literature to analyse the effectiveness of this tool. It examines the efficacy of assessment teams and considers wider applications of the Red List for protecting species than the criteria were originally designed for. Themes which have a significant impact on the effectiveness of the IUCN Red List are discussed including Data Deficient species and the Extinction Debt. The paper concludes that whilst effective assessments can be difficult to achieve due to these factors, the IUCN Red Lists have played a significant role in raising awareness of threatened species through their rigorous science and continue to inform policy makers from national through to international scales.
Background The IUCN Red List has become the most authoritative, comprehensive and internationally accepted system for assessing species’ extinction risk [1], [2]. The IUCN Red List Categories and Criteria were developed for classifying species at high risk of global extinction and as well as being a global system, provides methods of assessment at regional levels for evaluating extinction risk [3]. Since their adoption by the IUCN Council in 1994, the IUCN Red Lists have been used by
the UN as one of the indicators for Millennium Development Goal 7 on environmental sustainability and reveal trends in the overall extinction risk of species, allowing governments to monitor progress in reducing biodiversity loss [4]. The IUCN Red List is intended to be easily and widely understood and provides an objective framework [1], based on 8 Red List Categories of threat, from Least Concern to Extinct; linked to criteria based on population trend, size, structure and geographic range [4]. More than 77,300 species have been assessed [4]. The Red List has become a starting point for scientific research [5] including assessing trends in conservation progress and status [6], [2].
Strengths The IUCN Red Lists are hailed as systematic conservation assessments which identify priority areas for conservation [6], [7] ,[2]. They form a common standard [2] and enable threat assessments to be carried out at a common scale. Additionally, Red List assessments have informed other policy regimes such as CITES [2] and are becoming more representative due to the increasing volume of global assessments [2]. As this data builds, Red Lists are becoming useful in identifying conservation trends [8]. The research behind the assessments has taught scientists and policy makers about the bigger conservation picture; for example that
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670049493_BIOM4012_2017-2018 amphibians are at greater extinction risk than birds [5].
to sector attachment and geographic localisation [14].
The IUCN Red Lists are frequently used in national legislation [9], [10] and the systematic production of red lists has been called for in nations such as Iran, as they are effective in setting conservation priorities and providing information for regional and global conservation projects [11].
The case study contrasts strongly to assessment attempts undertaken in Iran [11] where expert knowledge was difficult to find and bring together and habitats difficult to assess. However, any country can have difficulties in making assessments and keeping species monitored and maintained [14]. Red Lists of Ecosystems have been applied well in Europe, the Americas, Australia and Africa [15] which may also be attributable to those factors demonstrated in Norway.
Red Lists are helpful in maximising conservation efforts in landscapes that support threatened species; indeed the very presence of a red list species can be used to identify and define habitat of importance [12]. Red Lists thereby raise awareness of conservation importance [13] and explain the threat through easily understandable language [14]: “You do not need to be a biologist to understand that ‘Critically Endangered’ is more worse off than ‘Vulnerable’.” Case Study: How the Assessment of Candidates for Red Listing was undertaken in Norway [14] The assignment of establishing a Norwegian Red List based on IUCN criteria was passed to the Norwegian Biodiversity Information Center (NBIC) by the Directorate for Nature Management. The NBIC formed groups of experts from different Norwegian scientific institutions and the scientific work took place within them, but actual responsibility for production of the list lay with the NBIC. The expert groups made the first decisions on whether a species was to be classified as ‘Threatened’ or ‘Not Threatened’. Species were then placed into one of the 8 IUCN categories. Experts came from many universities and conservation institutions. A culture of these organisations working together is prominent in the country. The NBIC tried to balance the expert teams to give an impression of independence with regards
The IUCN Red Lists have inspired the development of national and regional lists [2] which have then been employed to evaluate fine scale habitats such as agricultural seminatural field margins and to stress the importance of vanishing plant communities [12], [16]. Increasingly, red lists are being used from global to very local scales. The IUCN Red Lists have been used to identify threatened families, such as Orchidacae, which are exploited illegally [17], and their inclusion gives weight to the argument for protection through the inherent scientific authority of Red Lists, strengthening legal challenge [2] and ensuring a level of protection from illegal trade. This demonstrates how Red Lists have been identified as a tool for policy makers as a source of legitimate knowledge and as a simplified tool for presenting arguments in favour of nature conservation [14]. This was evident in the case of the Trillemarka forest of Norway when the local media and policy makers used the IUCN Red List data in making their relevant cases for conservation of the area resulting in its protection [14]. Red Lists have been employed as scientific evidence where industry that has a direct impact on the environment has a requirement to produce assessments of these impacts. The science has been used to inform operating
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670049493_BIOM4012_2017-2018 procedures with the aim of minimising these impacts [18]. Funding for species conservation has been prioritised by attributing conservation need to Red Listing [2]. The Bittern and the Nightjar in the UK have benefitted from this, demonstrated by their moves from National Red to Amber lists, due to well-targeted conservation [10]. Additionally, wading birds in the UK such as the Bar Tailed Godwit, benefit from Red Listing, as all stages of the lifecycle including migration, breeding grounds and stop overs are included [3]. Many of these species using British Wetland habitats for overwintering, but breed elsewhere [9]. However, many of the wetland habitats are designated areas through other means and so protection is buoyed through other conservation tools.
Limitations When data is fragmentary; it is not possible to apply the red list criteria, species are assigned as Data Deficient [3]. The system therefore relies on species being clearly defined and some specimens are not included when their taxonomic status is not yet classified [19]. For some species where little is known, as the system is inclusive [4] this could dilute the categories. Additionally, there can be mistakes in biology and taxonomy which can invalidate elements of the Red Lists [20]. Data deficient species are more likely to be at threat than their fully assessed counterparts [5] which can lead to unnoticed extinctions [13]. However, the IUCN note that assessors should be more inclined to assess these species as threatened [3] and it has been advocated that all data deficient species should be assessed as such until more is known about them [19]. Assessments for poorly known taxa should be submitted to expert assessor groups for evaluation [21]. Scientists often make decisions based on data which was not designed for this task [14] and
to compound this, data deficiency can be due to the very ecology of a species which makes it threatened, such as being shy, nocturnal, or living in a subterranean dwelling [19]. In order to solve this, trends in the data need to be understood [19], [10]. Researchers may even on the same assessment project apply the objective criteria differently [14] and additionally subjective handling of the data can be behind the objective criteria [11]. Successful conservation assessment requires skilled teams [7]. Conservation is often targeted on emblematic groups and it has been argued that the IUCN Red List excludes taxa with small body sizes, narrow distributions and low range dispersal [13]. However, it should be noted that 27,337 invertebrate species have been assessed [22] and therefore these generalisations should be taken with caution [23], [24], [25]. Additionally, conservation of the enigmatic Bittern has benefitted wetland species more widely [26]. The extinction debt [27], [28], may mean that Red Lists underestimate the threat to a species native to a threatened habitat due to the time lag between habitat loss and species extinction. Additionally, Red Lists focus on current conditions [12] which may exacerbate this inaccuracy in the data. Furthermore, species are not listed until they are in high peril when the chances of conservation success is reduced [29]. The IUCN categories have been described as ambiguous and fail to reflect the distance of an extant population from a risk averse minimum population size required for the long term viability and evolutionary potential of a population [30]. Additionally, the IUCN Red List has been criticised for not taking into account the value of genetic information and addressing the issue of species with fewer genetic relatives [31].
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670049493_BIOM4012_2017-2018 However, a constant minimum viable population number for all species is not a sufficient measure [32], and this criterion reflects a continuous version of Criterion D [3] and both ignore population fragmentation and trends in spatial distribution [24]. Norway was late in implementing a national red list [14] and the USA does not include all its IUCN Red List species in its national legislation [31]. These factors can affect a countries ability to produce trends. The Wryneck in the UK (which includes all Red List Species in its national lists) has been removed from the national list as it no longer breeds here [10] and the IUCN lists themselves can be affected by reclassifications and anomalies in taxonomy and biology [2], [20]. These factors do not in themselves demonstrate that conservation efforts are working, or trends are improving, although these anomalies may show as much.
Discussion The overall numbers of species on the red list is low; for the Red List to reach its full potential, efforts currently undertaken need to increase substantially both in terms of funds spent and Red Lists will need to monitor the status of at least 160,000 species [33]. Much of the research on red lists is negative and attempts to suggest additional criteria [30], [31] and [34], which does not directly affect the conservation effort. Additionally these suggestions are often not viable [25], [24]. The existing criteria are flexible enough that these elements are already included [2], [25]. More valuably, The IUCN conducts proactive work in prioritising sites for biodiversity conservation, to help focus funding and as a tool for conservation efforts at the local scale [35]. The Red List criteria are simple and easy to understand [14] and it is important for them to remain as such so that they can be understood by non-technical roles and continue to be implemented into policy [11].
However, listing in Red Lists, or not, does not determine conservation action. The legislation and processes within the USA could be improved, particularly by ensuring that all IUCN Red List species are incorporated into legislation [29], however, this would be a lengthy and bureaucratic process and may not achieve conservation action. In the UK, all species in the IUCN Red List are incorporated into national legislation [9] however, some species have been removed merely because their ecology within the UK has changed [10]. The International Red Lists need to work more closely with national lists [2] however, assessment is useless unless it is incorporated into implementation plans [7]. Discrepancies have been found between Regional legislation – the Habitats Directive - and IUCN Red list data [36]. This variation is likely due to differences of scale. For example, the Bar Tailed Godwit has a very large range and the European population is faring better than its more eastern counterparts [37]. Due to the application of the criteria, the IUCN list will take a naturally more pessimistic view [3]. The extinction debt could have serious implications for the red lists due to the time lag between habitat loss and species extinction [27], [28]. In island ecosystems, threats act simultaneously producing impacts that reverberate through entire ecosystems; a calculation of between 2000 and 2800 endemic island plant species on the verge of extinction world-wide could be an underestimation [16]. This can all be exacerbated when countries are late to implement red lists [14]. Red Lists of Ecosystems are therefore important to assess the threat to areas which support species [15]. However, the extinction of communities are much more difficult to define than a species and it is problematic to assess when a community is so degraded that it doesn’t exist anymore [38]. Ecosystems vary continuously over a gradient and are not discreet [15] unlike species.
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670049493_BIOM4012_2017-2018 Red Lists have been useful in illustrating trends over time [6]. The relatively short trend period covered since implementation means that species that are declining at a slower rate and have been given threatened status could be at risk of regional extinction [9]. Additionally, trends for species in decline during the 1970s that have now levelled off may not show up in the data and elude red list inclusion despite being at risk of extinction [9].
6. Hoffman, M. (2010). The Impact of Conservation on the Status of the World’s Vertebrates. Science 330, 1503–1509.
Despite being far from complete [33], the IUCN Red List remains true to its aim of providing comprehensive information about the conservation of species [2]. It continues to provide information to policy makers [10] and through its easy to understand language [14] has an important role to play in raising conservation awareness [13].
8. James F. Quayle, author, Leah R. Ramsay, author, and David F. Fraser, author (2007). Trend in the Status of Breeding Bird Fauna in British Columbia, Canada, Based on the IUCN Red List Index Method. Conserv. Biol., 1241.
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