Forms Of Rarity Research Articles

Local rarity of vascular plants in a human-dominated landscape of Northern Ethiopia

Abstract Understanding species rarity is crucial in developing conservation priorities by reasonably allocating limited funds effectively. The local rarity of vascular plants in the Abune Yosef mountain range in Ethiopia was assessed using Rabinowitz’s seven forms of rarity. Of the 199 vascular species analyzed for rarity, 171 species (86%) were rare. On the contrary, only 28 species (14%) were found to be common in the study area. The rarity index (rr) ranged from 0.46 to 1. On the other hand, species range (gri), total density of mature individuals (psi), and Habitat specificity (hsi) ranges were 0.99–1, 0–1, and 0.04–1, respectively. Land transformation was identified as likely the main driver for rarity in the study area. The characterization of the plant species of the Abune Yosef mountain range provided here can be used in the management of this threatened landscape and provide a basis for broader national-level conservation efforts of plants within the biodiverse landscapes of Ethiopia.

Diversity and distribution of Lentibulariaceae in Bahia state, Brazil: implications for phytogeography and conservation

Bahia state harbours an immense diversity of plant species with several cases of endemism, especially in the savanna wetlands, typical ecosystems where most Lentibulariaceae representatives occur. In this context, we aimed to improve the characterization of these savanna wetlands in terms of species richness of Lentibulariaceae, their phytogeographic patterns, endemism, forms of rarity, threats to their habitats, and conservation efforts. Herein we present the synopsis of the 42 species of Lentibulariaceae that occur in Bahia state, providing short diagnostic characterization, photographs of living specimens, updated geographic distribution displayed in maps, new records, and discussion concerning phytogeographic patterns, endemism, rarity, habitat characterization and current scenario of threats and conservation. Our results show a disjunct distribution and similarity in Lentibulariaceae species composition between savanna wetlands, corroborating previous hypotheses of vegetation connections during moister climatic conditions in the past. Moreover, differences in species composition among different restinga areas are consistent with biogeographical and paleomodelling studies pointing the São Francisco River as a geographic barrier influencing speciation and genetic diversity. Finally, we emphasize the situation of abandonment in some Protected Areas, lacking proper infrastructure, managers, management plans and board, and insufficient results for the effective conservation and protection of the environment and species.

Taxonomic rarity and functional originality of freshwater fishes and their responses to anthropogenic habitat alterations

Abstract The human alteration of habitats is a major driver in the decline of biodiversity worldwide. However, the relationships between different forms of rarity, including both taxonomic and functional aspects, are poorly known. Two relationships were examined in this study: (i) between the different forms of taxonomic rarity and functional originality of lotic fishes; and (ii) between rarity indices and the degree of human alterations. Stream fish communities at 429 stream and river sites were sampled between 2013 and 2018. The taxonomic rarity of fishes was characterized based on their local rarity, habitat specificity and geographical restrictedness. The functional originality of each species was also quantified by using ecomorphological traits, and the relationships between the different indices and their responses to human habitat degradation were explored. Only weak or medium level correlations were found among the indices of taxonomic rarity. A combined taxonomic rarity index showed that overall taxonomic rarity was determined most strongly by local rarity, followed by habitat specificity, and finally, geographical restrictedness. Functional originality was not related either to individual rarity indices or the combined taxonomic rarity index. Mean taxonomic rarity of species was correlated with the degree of habitat degradation of the sites. Contrary to taxonomic rarity, mean functional originality of species increased with the degree of human alteration. This study shows that a more exact characterization of species rarity requires multiple metrics, including functional ones, because these indices respond differently to human alterations. Combined indices of rarity can help to prioritize species level conservation actions, although single rarity metrics are still needed to adapt these actions to species attributes (e.g. endemism or unique functions). Species level conservation would benefit from including the evaluation of functional rarity into conservation policy.

The Seven Forms of Challenges in the Wildlife Trade

Initiatives that aim to regulate the international wildlife trade must take into account its multiple and often complex dimensions in order to be effective. To do this, it is essential to understand the interactions between three of the key dimensions of the wildlife trade: (1) taxonomic unit, (2) geographic origin, and (3) product form and transformation. We propose a framework to provide a structured approach to defining the complexities of the wildlife trade, based on Rabinowitz’s seven forms of rarity. We demonstrate the complexities and how they apply to our framework using two contrasting examples: the trade in elephant ivory, and the horticultural orchid trade. Further we use the framework to map different traceability solutions. To be as efficient as possible, efforts to tackle the illegal and unsustainable utilisation of wildlife should take a more structured approach. This framework identifies challenges that current initiatives may face, how they may interact and provides a structure for designing future interventions.

Anthropogenic landscapes support fewer rare bee species

The response of rare species to human land use is poorly known because rarity is difficult to study; however, it is also important because rare species compose most of biodiversity, and are disproportionately vulnerable. Regional bee pollinator faunas have not been assessed for rarity outside of Europe. Therefore, we do not know to what extent anthropogenic landscapes support rare North American bee biodiversity. We ask how richness and abundance of bee species respond to land use, within quartiles of species defined by their numerical, phenological, and geographical rarity. We conducted a field study to sample bee communities in forested, agricultural, and urban landscapes replicated across a large spatial extent of the northeastern United States. We used large independent data sets to classify observed bee species according to three forms of rarity: their numerical rarity (low regional frequency in a museum-based data set), phenological rarity (short flight season length) and geographical rarity (small range size). For all three forms of rarity, we found half as many rare bee species in agricultural landscapes compared to forest. We found half as many phenologically rare species in urban landscapes. Bees that had both shorter flight seasons and smaller range sizes were between one-third and one-half as rich in both types of anthropogenic landscapes, regardless of regional frequency. Although a minority of rare bee species were found in anthropogenic landscapes, our overall conclusion is that the native vegetation of our region, forest, is critical for supporting rare bee biodiversity.

Rarity as an indicator of endangerment in neotropical frogs

Anurans are endangered worldwide and declining populations are in need of urgent conservation management. Optimal conservation actions ideally rely on basic ecological and natural history data, such as population size, habitat requirements and availability, or biotic interactions. Unfortunately, we lack basic natural history information for most frogs, making it difficult to determine species vulnerability in nature. Our goal in this study was to apply a ‘rarity’ index to assess whether rarity and other endangerment assessment criteria can serve complementary roles in conservation prioritization. We applied Rabinowitz’ “eight forms of rarity” classification, which is based on geographic range, habitat specificity, and local population size, to evaluate its value as an indicator of species vulnerability in the anuran assemblage endemic to the Atlantic Coastal Forest of Brazil. We compared patterns of rarity in anurans to IUCN endangerment status, and investigated possible relationships between spatial traits (topographic complexity, elevation, and latitudinal variation) and groups of species with different forms of rarity. We found similar patterns of rarity across taxonomic groups and among local anuran communities, indicating that these patterns are consistent across taxa and geographic scales. We provide evidence that rarity rankings increase in areas of higher elevation and topographic complexity. Our results also indicate that the majority of rare species are classified as threatened according to IUCN; however, 32 species ranked as rare are still considered ‘least concern’ or ‘data deficient’ by the current Brazilian red list of threatened species. We propose that including rarity categories in endangerment assessment for anurans can improve our ability to prioritize conservation efforts for threatened amphibian taxa.

Risks to birds traded for African traditional medicine: a quantitative assessment.

Few regional or continent-wide assessments of bird use for traditional medicine have been attempted anywhere in the world. Africa has the highest known diversity of bird species used for this purpose. This study assesses the vulnerability of 354 bird species used for traditional medicine in 25 African countries, from 205 genera, 70 families, and 25 orders. The orders most represented were Passeriformes (107 species), Falconiformes (45 species), and Coraciiformes (24 species), and the families Accipitridae (37 species), Ardeidae (15 species), and Bucerotidae (12 species). The Barn owl (Tyto alba) was the most widely sold species (seven countries). The similarity of avifaunal orders traded is high (analogous to “morphospecies”, and using Sørensen's index), which suggests opportunities for a common understanding of cultural factors driving demand. The highest similarity was between bird orders sold in markets of Benin vs. Burkina Faso (90%), but even bird orders sold in two geographically separated countries (Benin vs. South Africa and Nigeria vs. South Africa) were 87% and 81% similar, respectively. Rabinowitz's “7 forms of rarity” model, used to group species according to commonness or rarity, indicated that 24% of traded bird species are very common, locally abundant in several habitats, and occur over a large geographical area, but 10% are rare, occur in low numbers in specific habitats, and over a small geographical area. The order with the highest proportion of rare species was the Musophagiformes. An analysis of species mass (as a proxy for size) indicated that large and/or conspicuous species tend to be targeted by harvesters for the traditional medicine trade. Furthermore, based on cluster analyses for species groups of similar risk, vultures, hornbills, and other large avifauna, such as bustards, are most threatened by selective harvesting and should be prioritised for conservation action.

EFSA's 19th Scientific Colloquium on Biodiversity as protection goal in environmental risk assessment for EU agro‐ecosystems

EFSA Supporting PublicationsVolume 11, Issue 4 583E Event reportOpen Access EFSA's 19th Scientific Colloquium on Biodiversity as protection goal in environmental risk assessment for EU agro-ecosystems European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author First published: 14 April 2014 https://doi.org/10.2903/sp.efsa.2014.EN-583 Published date: 14 April 2014 Question number: EFSA-Q-2013-00912 AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat VII. References AMIGA http://www.amigaproject.eu/project/objectives/. EFSA, 2010. Report on the PPR stakeholder workshop Protection goals for environmental risk assessment of pesticide: What and where to protect? EFSA Journal 2010; 8(7):1672, 46 pp. doi:10.2903/j.efsa.2010.1672. EFSA, 2011; Review of current practices of environmental risk assessment within EFSA. Supporting Publication: 2011:116. 39 p. EFSA GMO Panel (EFSA Panel on Genetically Modifed Organisms), 2010. Guidance on the environmental risk assessment of genetically modifed plants. EFSA Journal 2010; 8(11):1879. 111 pp. doi:10.2903/j.efsa.2010.1879. EFSA GMO Panel (EFSA Panel on Genetically Modifed Organisms), 2013. Guidance on the environmental risk assessment of genetically modifed animals. EFSA Journal 2013; 11(5):3200, 190 pp. doi:10.2903/j.efsa.2013.3200. EFSA PLH Panel (EFSA Panel on Plant Health), 2010. Guidance on a harmonised framework for pest risk assessment and the identifcation and evaluation of pest risk management options by EFSA. EFSA Journal 2010; 8(2):1495, 66 pp. doi:10.2093/j.efsa.2010.1495. EFSA PLH Panel (EFSA Panel on Plant Health), 2011. Guidance on the environmental risk assessment of plant pests. EFSA Journal 2011; 9(12):2460, 121 pp. doi:10.2093/j. efsa.2011.2460. EFSA PPR Panel (EFSA Panel on Plant Protection Products and their Residues), 2009. Guidance Document on Risk Assessment for Birds & Mammals on request from EFSA. EFSA Journal 2009; 7(12): 1438. doi:10.2903/j.efsa.2009.1438. EFSA PPR Panel (EFSA Panel on Plant Protection Products and their Residues), 2010. Scientifc Opinion on the development of specifc protection goal options for environmental risk assessment of pesticides, in particular in relation to the revision of the Guidance Documents on Aquatic and Terrestrial Ecotoxicology (SANCO/3268/2001 and SANCO/10329/2002). EFSA Journal 2010; 8(10):1821. 55 pp. doi:10.2903/j.efsa.2010.1821. EFSA PPR Panel (EFSA Panel on Plant Protection Products and their Residues), 2013. Guidance on tiered risk assessment for plant protection products for aquatic organisms in edge-of-feld surface waters. EFSA Journal 2013; 11(7):3290, 268 pp. doi:10.2903/j. efsa.2013.3290. Hommen U, Baveco JMH, Galic N and van den Brink PJ, 2010. Potential application of ecological models in the European environmental risk assessment of chemicals. I. Review of protection goals in EU directives and regulations. Integrated Environmental Assessment and Management, 6, 325– 337. Nienstedt KM, Brock TCM, van Wensem J, Montforts M, Hart A, Aagaard A, Alix A, Boesten J, Bopp SK, Brown C, Capri E, Forbes V, Koepp H, Liess M, Luttik R, Maltby L, Sousa J P, Streissl F and Hardy AR, 2012. Development of a framework based on an ecosystem services approach for deriving specifc protection goals for environmental risk assessment of pesticides. Sci Total Environ, 415, 31– 38. Rabinowitz D, 1981. Seven forms of rarity. Pages 205– 217 in H. Synge, editor. The biological aspects of rare plant conservation. Wiley, New York. Topping CJ, Kjær LJ, Hommen U, Høye TT, Preuss TG, Sibly RM and van Vliet P. 2014 in press. Recovery based on plot experiments is a poor predictor of landscape-level population impacts of agricultural pesticides. Environmental Toxicology and Chemistry. Accepted manuscript online: 5 Sep 2013, DOI: 10.1002/etc.2388. Volume11, Issue4April 2014583E This article also appears in:Scientific colloquia ReferencesRelatedInformation

Long-term differences in extinction risk among the seven forms of rarity

Rarity is widely used to predict the vulnerability of species to extinction. Species can be rare in markedly different ways, but the relative impacts of these different forms of rarity on extinction risk are poorly known and cannot be determined through observations of species that are not yet extinct. The fossil record provides a valuable archive with which we can directly determine which aspects of rarity lead to the greatest risk. Previous palaeontological analyses confirm that rarity is associated with extinction risk, but the relative contributions of different types of rarity to extinction risk remain unknown because their impacts have never been examined simultaneously. Here, we analyse a global database of fossil marine animals spanning the past 500 million years, examining differential extinction with respect to multiple rarity types within each geological stage. We observe systematic differences in extinction risk over time among marine genera classified according to their rarity. Geographic range played a primary role in determining extinction, and habitat breadth a secondary role, whereas local abundance had little effect. These results suggest that current reductions in geographic range size will lead to pronounced increases in long-term extinction risk even if local populations are relatively large at present.

Assessing rarity and threat in an arid-zone flora

An understanding of rarity and how it relates to extinction risk is a central concern of conservation biology. Classic conceptions of rarity revolve around spatial rarity, based on distribution and abundance, rather than temporal rarity, where species may be common following certain conditions but rare for most of the time. This form of rarity is likely to be especially prevalent in highly variable arid systems. Rarity in the arid zone is also characterised by poorly understood threats, such as grazing, and may also reflect low collection effort given the vast and inaccessible areas involved. This study explores rarity and threat in the arid zone, based on the flora of a large region of western Queensland. The status of all species known to occur in the study area was systematically assessed, and the current list of threatened species was examined for bias in forms of rarity, life forms and habitats. Five threat syndromes were identified, arising from the interaction of plant biology and threatening processes. Over 60 potentially threatened species have been overlooked in the listing process. The list is dominated by narrow endemics from residual and spring habitats and the species from springs at least are genuinely threatened. Widespread but sparsely occurring species are under-represented in the current list, as are grasses. With the exception of spring-dependent species, plant conservation in western Queensland is currently constrained by lack of basic data on distribution, abundance, population dynamics and realistic threat syndromes for nearly all species. Separating the influence of genuine rarity, temporal rarity and low collection effort, as well as a more detailed understanding of threatening processes are needed to address plant conservation in the arid zone.

Rarity and decline in palaeoendemic Martino's vole Dinaromys bogdanovi

ABSTRACT Martino's vole Dinaromys bogdanovi is the only living member of the Tertiary genus Dinaromys, and probably also the only surviving member of the Pliomys lineage. The range of the genus Dinaromys has historically been small and its rate of evolution has been low. Martino's vole shows all three attributes of rarity in accordance with Rabinowitz's ‘seven forms of rarity’ model: (i) its range is estimated at 43 545 km2 but the area of occupancy is <5200 km2; (ii) its habitat requirements are narrow and the species is strictly tied to exposed, karstified bedrock; and (iii) current populations are invariably small and frequently isolated. The Pleistocene range of Martino's vole exceeded the recent one, at least in the north‐western part of the Balkans, and its shrinkage continued into the Holocene. Martino's vole may be in competition with the European snow vole Chionomys nivalis, which has a very similar morphology and presumably identical habitat requirements, but is shifted towards an r‐selected life‐history strategy. Long‐term sympatry of these voles has probably resulted in competitive exclusion of the relatively K‐selected Martino's vole by the relatively r‐selected European snow vole. Martino's vole consists of two deeply divergent (about one million years ago) phylogeographical lineages, which may represent distinct cryptic species. Rarity is particularly pronounced in the north‐western lineage to the west of the Neretva River, where rocky habitats are largely occupied by the European snow vole. In the IUCN Red List of Threatened Animals, Martino's vole is classified as ‘near threatened’. However, the north‐western lineage, which is phylogeographically most divergent and has the greatest genetic diversity, is classed as a ‘vulnerable’ evolutionary significant unit on the basis of its small area of occupancy (<2000 km2). Long‐term population monitoring is an essential step in evaluating the conservation needs of Martino's vole.

Mining with rarity

Rare objects are often of great interest and great value. Until recently, however, rarity has not received much attention in the context of data mining. Now, as increasingly complex real-world problems are addressed, rarity, and the related problem of imbalanced data, are taking center stage. This article discusses the role that rare classes and rare cases play in data mining. The problems that can result from these two forms of rarity are described in detail, as are methods for addressing these problems. These descriptions utilize examples from existing research. So that this article provides a good survey of the literature on rarity in data mining. This article also demonstrates that rare classes and rare cases are very similar phenomena---both forms of rarity are shown to cause similar problems during data mining and benefit from the same remediation methods.

Tree species distribution in forests of the Albertine Rift, western Uganda

AbstractThe distribution of trees of diameter ≥ 10 cm was assessed in twelve 1‐ha (20 × 500 m) plots of Bwindi Impenetrable National Park (BINP), Kasyoha‐Kitomi Forest Reserve (KKFR), Kibale National Park (KNP) and Budongo Forest Reserve (BFR) in the Albertine Rift, western Uganda. Distribution was analysed at three spatial scales: local (1 ha plots), within individual forests (>300 km2 each) and regional (>56,000 km2). The aim was to classify tree species into Rabinowitz's seven forms of rarity. We recorded 5747 trees in 53 families, 159 genera, and 212 species. Twenty‐two families had one species each while the rest had between two and 25 species. Number of species was highest in the family Euphorbiaceae (25 species) followed by Meliaceae and Rubiaceae with sixteen species each. Based on Rabinowitz's forms of rarity, 93% of the species were geographically widespread, 47% were restricted to a single forest type, while 41% occurred at densities of <1 individual ha−1. Ubiquitous common species with high frequency and high local abundance occurred in the Meliaceae, Flacourtiaceae, Moraceae and Apocynaceae families. Conservation of geographically widespread species should focus on landscape rather than site specific approaches. The rarest species would benefit from species‐specific strategies.

Beyond eight forms of rarity: which species are threatened and which will be next?

AbstractWe tabulate three measures of rarity: local abundance, breeding range size and elevational extent for the passerine birds of the New World. We determine what fraction of species is threatened with extinction within the combinations of these three measures. Species with smaller ranges, lower abundances and narrower elevational bands suffer higher levels of threat across lowland, montane and island species. For a given range size, lowland species suffer higher levels of threat than island or montane species. (This is counter to the intuition that island species — and those isolated on mountain tops — might be ecologically naïve.) When all three factors are considered together, there is only a slight tendency for lowland species to be disproportionately more threatened. Simply, island and montane species tend to be relatively common within their restricted ranges and their increased abundance reduces their likelihood of being threatened. Elevation is a consistent but relatively unimportant factor in determining threat; abundance and range size are much more important, and have an interactive effect on threatened status. We calculate the number of humans with which each species shares its breeding range, and find that this number does not aid in predicting threat status.

Seven forms of rarity in mammals

AbstractConservation biologists have identified threats to the survival of about a quarter of the mammalian species; to identify patterns of rarity and commonness of mammals, we studied a global sample of 1212 species (about 28% of the mammals) using the ‘7 forms of rarity’ model (in which species are roughly divided into above and below the median for local population density, species’ range area, and number of habitat types).From a niche‐based hypothesis of abundance and distribution, we predicted that mammals would exhibit a bimodal pattern of rarity and commonness, with an overabundance of species in the relatively rarest and most common categories; and just such a significant bimodal pattern emerged, with over a quarter of the species classified as exceedingly rare and a further quarter very common, supporting the niche‐based hypothesis.Orders that include large mammals, including perissodactyls, primates, diprotodonts, and carnivores, exhibited significantly high proportions of relatively rare species; and tropical zoogeographic regions, especially Indomalaya, had relatively high proportions of species in the rarest category.Significant biases in the available data on mammals included under‐sampling of small species like rodents and bats, and a relative paucity of data on zoogeographic regions outside of North America and Australia.Mammalian species listed as of conservation concern by the IUCN occurred in all cells of the model, indicating that even relatively common species can be listed as threatened under some conditions; but we also found that sixty‐three species were relatively rare in all three criteria of the 7‐forms model but were not listed as threatened, indicating potential candidates for further study.Mammals may be a group of animals where rarity or commonness is a natural aspect of species biology, both confirming and perhaps partly explaining the large proportion of mammals assigned threatened status.

Why is the Cape Peninsula so rich in plant species? An analysis of the independent diversity components

With 2285 species of higher plants crammed into 471 km2, the flora of South Africa's Cape Peninsula is exceptionally rich. Similar sized areas in other Mediterranean-climate region biodiversity hot-spots support between 4.7 and 2.7 times fewer species. The high plant species richness of the Cape Peninsula is due to the exceptionally high turnover between moderately species-rich sites in different habitats (beta diversity) and between sites in similar habitats along geographical gradients (gamma diversity). Highest beta diversity, encompassing almost complete turnover, was recorded along soil fertility gradients. Although similar patterns for these independent components explain the richness of other regions in the Cape Floristic Region, it is the very long and steep habitat gradients of the Cape Peninsula that makes this region exceptionally rich. Furthermore, the flora is characterized by a high degree of rarity, a phenomenon that undoubtedly influences the turnover. Future research should focus on developing a biological and ecological understanding of the different forms of rarity and integrating this into management plans for the maintenance of biodiversity.

Ecological Aspects of the Geographical Distribution and Diversity of Mammalian Species

Using the comprehensive collection of range maps compiled for 679 species of North American mammals by Hall, we compute the distribution in the sizes of the geographical ranges of these mammalian species. The distribution is roughly lognormal. This corresponds to high skewing on a linear scale toward small geographical ranges, with a median geographical range of around 1% of the area of North America; only about 2% of the species have ranges exceeding 50% of this area. There are differences among taxa; skewing is high for bats, rodents, insectivores, and lagomorphs and less pronounced for carnivores and artiodactyls. In contrast to Rabinowitz et al.'s study of "seven forms of rarity," which found most of the British flora in the study to be widely distributed throughout Britain, we find that most mammalian species in North America have relatively restricted geographical ranges. This difference may derive from systematic differences between plants and animals, or from the small size and relative homogeneity of Britain, or from other causes. The fact that half or more of North American mammals have ranges smaller than the combined size of Nicaragua and Honduras has implications for conservation biology, especially because such restricted patterns are more pronounced in the tropics, where deforestation is currently most severe. As mentioned by earlier authors, there are both latitudinal and longitudinal gradients in range size, with average ranges increasing to the North and to the East. At any one latitude, however, there is wide variability in range size. Corresponding to these gradients in range size are latitudinal and longitudinal gradients in species density, with density increasing as average range size decreases. These latitudinal gradients have long been appreciated, but we think that the longitudinal gradients may ultimately prove more illuminating because they are less confounded by the kinds of systematic changes (in temperature, etc.) that accompany latitudinal change. Following Aldrich and Loftas, we identify 23 distinct habitat types in North America and show that patterns both in geographical range and in species density are correlated with the number of different habitats a species range includes: high density of species and small geographical range sizes occur in areas of high habitat diversity. Correlations between the number of habitats (and the average geographical range of habitats) versus latitude and longitude explain some, but not all, of the geographic variation in species' range patterns noted in this article. Finally, we show that species are more habitat specific (having ranges embracing fewer distinct habitat types) toward more southern latitudes and toward more western longitudes.