Geographic discrepancies between global and local rarity richness patterns and the implications for conservation

The emerging interest in the biological and conservation significance of locally rare species prompts a number of questions about their correspondence with other categories of biodiversity, especially global rarity. Here we present an analysis of the correspondence between the distributions of globally and locally rare plants. Using biological hotspots of rarity as our framework, we evaluate the extent to which conservation of globally rare plants will act as a surrogate for conservation of locally rare taxa. Subsequently, we aim to identify gaps between rarity hotspots and protected land to guide conservation planning. We compiled distribution data for globally and locally rare plants from botanically diverse Napa County, California into a geographic information system. We then generated richness maps highlighting hotspots of global and local rarity. Following this, we overlaid the distribution of these hotspots with the distribution of protected lands to identify conservation gaps. Based on occupancy of 1 km² grid cells, we found that over half of Napa County is occupied by at least one globally or locally rare plant. Hotspots of global and local rarity occurred in a substantially smaller portion of the county. Of these hotspots, less than 5% were classified as multi-scale hotspots, i.e. they were hotspots of global and local rarity. Although, several hotspots corresponded with the 483 km² of protected lands in Napa County, some of the richest areas did not. Thus, our results show that there are important conservation gaps in Napa County. Furthermore, if only hotspots of global rarity are preserved, only a subset of locally rare plants will be protected. Therefore, conservation of global, local, and multi-scale hotspots needs serious consideration if the goals are to protect a larger variety of biological attributes, prevent extinction, and limit extirpation in Napa County.     

Forms of rarity of tree species in the southern Brazilian Atlantic rainforest

The assessment of species rarity considers local abundance (scarce or abundant population), habitat affinity (stenoecious or euryecious species), and geographic distribution (stenotopic or eurytopic species). When analyzed together these variables classify species into eight categories, from common species to those having small populations, unique habitats, and restricted geographic distribution (form 7), as proposed by Rabinowitz in 1981. Based on these categories, it is possible to calculate the frequency of the different forms of rarity of the species present in a given site. The Brazilian Atlantic rainforest is considered a hotspot of the world biodiversity harboring many endemic species, which have restricted geographic distribution. Our objective was to identify the forms of rarity of tree species and their proportions in the southern portion of the Brazilian Atlantic rainforest using Rabinowitz’s forms of rarity. All the seven forms of rarity are present in the 846 tree species we analyzed: 46% eurytopic and 54% stenotopic, 73% euryecious and 27% stenoecious, 76% locally abundant and 24% locally scarce species. Eurytopic, euryecious locally abundant species accounted for 41.1%, whereas 58.9% were somehow rare: 4.5% eurytopic, euryecious locally scarce, 0.2% eurytopic, stenoecious locally abundant, 0.1% eurytopic, stenoecious locally scarce, 19.5% stenotopic, euryecious locally abundant, 8.0% stenotopic, euryecious locally scarce, 15.6% stenotopic, stenoecious locally abundant, and 11.0% stenotopic, stenoecious locally scarce. Considering that the most restrictive forms of rarity precedes extinction, the application of Rabinowitz’s system demonstrated that most tree species of the southern Brazilian Atlantic rainforest are threatened due to their restricted geographic distribution, restriction to a single habitat, reduced local abundance, or even to a combination of these variables.     

Multiple measures are necessary to assess rarity in macro-molluscs: a case study from southeastern Australia

Our knowledge of suitable criteria to determine rarity in most marine invertebrates is lacking, thus hindering targeted impact studies, long-term monitoring programs, and associated conservation strategies. Standardized definitions of rarity are required to enable comparisons of different assemblages and taxa. Gaston (Rarity, Chapman and Hall, Melbourne, 1994) has recommended that rare species are defined as the lowest quartile of species in the assemblage. In this study, the 25% ‘cut-off’ was applied to intertidal macro-molluscs along the Illawarra Coast, Australia from 200 surveys of 13 reefs, using three measures of population structure; (1) local abundance (numerical rarity); (2) number of locations (spatial rarity) and; (3) percent of surveys (temporal rarity). Rare species were consequently defined as those species with no more than; (1) a local abundance of two individuals; (2) a regional occurrence at two reefs and/or; (3) a temporal occurrence in 2% of all surveys. These cut-off values increased when only intertidal specialists were analysed. Using a combination of all three measures, 62 species (42%) were classified as regionally rare, but only four of these were true intertidal specialists. Most species were rare by only one or two definitions of rarity; illustrating the importance of considering multiple measures of rarity and the need to design specifically targeted survey methods for future monitoring. Many species that are rare by all three definitions are likely to be temporary immigrants, as subtidal species were significantly more likely to be classified as rare. Clearly many factors can influence the rarity of marine invertebrates on intertidal reefs, and these must all be considered to set appropriate conservation priorities.     

A decision tool for listing species for protection on different geographic scales and administrative levels

An important task in conservation biology is to assess the spatial scale pertinent for species protection since some species may require protection throughout their distribution, others in only part of their range. Once this is done, species can be correctly identified for listing at different administrative levels (e.g. continental, national, and local). Here, we propose an objective method to list taxa at nested administrative levels based on three criteria (responsibility, rarity and vulnerability). We tested the method using quantitative data on the distribution, abundance and decline of orchids in France. The proposed method enables increased protection status in regions where species’ abundance and diversity are higher, gives priority to species for which an individual administrative unit has high responsibility and allows objective integration of species decline at different administrative levels. The method also enables the integration of locally rare species at their distribution limits and avoids repetition of species listing across second-level administrative units. The use of an objective method such as this could contribute to a standardised system of priority setting that integrates the geographic scale of rarity in relation to different administrative levels for protection.     

Taxon size predicts rates of rarity in vascular plants

We surveyed rarity in the vascular plants of the continental U.S.A. and Canada and the vascular plants of Hawaii to test the hypothesis that rates of rarity are independent of taxonomic group size. We demonstrated that taxonomic groups of plants with few species consistently contained fewer than the expected numbers of rare species. This pattern was apparent at the levels of genus, family, order and class. We also found that the pattern remained when we examined rates of rarity by comparing sister taxa that share a common ancestor. This pattern may arise from either differential speciation and extinction patterns or taxonomic bias in species designations (lumping and splitting). The pattern of lineages with few species demonstrating reduced rates of rarity is opposite to that previously observed in mammals and birds. If the protection of representatives from a diversity of lineages is a conservation objective, plant conservation is facilitated by the fact that relatively few species-poor lineages contain rare species.     

Patterns of rare fish and aquatic insects in a southwestern French river catchment in relation to simple physical variables

Most of our current understanding of rarity has come from studies of terrestrial plants and animals, whereas freshwater habitats remain poorly documented under this topic. Here we considered the spatial distribution patterns of rarity at the river catchment scale, for five freshwater taxa (fish, Ephemeroptera, Plecoptera, Trichoptera and Coleoptera) in southwestern France. The data were collected at 554 and 155 sampling sites for fish and aquatic insects, respectively. General Linear Modelling was used to assess the influence of some typological variables (elevation, stream order, distance from source, and reach slope) on local numbers of rare species (restricted range). The relative numbers of rare species per taxa varied from 16% (Plecoptera) to 59% (Trichoptera). GLM chiefly yielded highly significant correlations between rarity and distance from the source and/or elevation for all taxa, showing that numbers of rare stream species increase towards downstream areas within the stream system. The spatial patterns in rarity for the different study taxa were rather concordant, probably as a result of similar responses to environmental conditions. By focusing on integrative variables, we emphasized the influence of river typology on the rarity of aquatic animals. Areas which carry rare species may concentrate an important fraction of the regional biodiversity. If end-users need geographic models (i.e. maps) to design river management frameworks, numerical patterning is needed to provide theoretical backgrounds: by predicting what the rarity should be like in a given area, we can provide explicit spatial schemes that may be useful to target further research, and to implement management options.     

Defining plant functional groups to guide rare plant management

To effectively manage plant populations for conservation, there is a need to provide reliable information on the conditions required for maintaining viable populations. This is particularly true for the management of populations of rare plant taxa. Western Australia contains over 45% of Australia’s gazetted rare or threatened flora, 80% of which are found within the highly fragmented southwest region. Resources do not exist to undertake comprehensive studies on the population dynamics and demographics for every rare plant of this diverse region. Here, we describe a method of classifying rare plant taxa into functional groups as a basis for guiding rare flora conservation and management. Data on four floral and two life-history traits were collected for each of the 351 declared rare flora taxa of Western Australia. A hierarchical, agglomerative clustering method was applied to the resulting taxa by traits matrix to extract emergent groupings of plant taxa. The resulting polythetic groups were analysed to determine the variation in traits, including response to disturbance and recorded flower visitors, and how these may affect population persistence in a fragmented landscape. Multivariate methods were used to define emergent groups based on a combination of floral structure and life-history traits of the declared rare flora of Western Australia. Seven emergent functional groups were identified and were largely differentiated by flower shape and life form. These seven functional groupings varied significantly in their response to disturbance. By deriving these functional groups, we plan to develop models for each group on how rates of pollination, seed production and seed fitness are affected by population size and landscape context. The rationale would be to use these profiles to determine whether there are thresholds in population size or position in the landscape at which reproductive rates severely decline. General management guidelines could then be developed for each functional group. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Nomenclature Paczkowska and Chapman (2000).     

Für welche Pflanzenarten hat die Schweiz eine internationale Verantwortung?

Eggenberg S. and Landolt E. 2006. For which plant species does Switzerland have an international responsibility? Bot. Helv. 116: 119 – 133. Priorities in plant species conservation are often based on national Red Lists. In an international context, however, the Red List status (threat) of a species within a limited territory may be misleading because the local disappearance of a species may or may not have serious implications for its global persistence. A second important aspect to consider in species conservation is therefore the responsibility of a country for the species, i.e. the importance of the conservation of local populations for the persistence of the species worldwide. In this contribution, we assess the responsibility of Switzerland for its vascular flora using three biogeographical criteria: (1) the Swiss portion of the species range (high responsibility for species with a large fraction of the range in Switzerland), (2) the degree of endemism (high responsibility for species with a small total range) and (3) the degree of isolation (high responsibility for isolated outposts, which may contain a large part of a species’ genetic variation). The three criteria were derived for each species from global and European distribution maps, and were then combined to an overall index of responsibility. On this basis, 397 taxa for which Switzerland has an intermediate to high international responsibility were identified. These are almost 15% of the whole vascular flora of Switzerland. Of the 397 taxa, 75% are endemic species of the Alps, and 48% are threatened taxa within Switzerland. The Responsibility List can be used together with the Red List to set priorities in plant conservation or to identify areas of particular floristic value. Manuskript angenommen am 11. September 2006     

Conservation of important plants from the Ionian Islands at the Balkan Botanic Garden of Kroussia,N Greece: using GIS to link the in situ collection data with plant propagation and <Emphasis Type="Italic">ex situ</Emphasis> cultivation

The Balkan Botanic Garden of Kroussia (BBGK) is dedicated to the ex situ conservation of native plants of Greece and the Balkans. The BBGK has formulated a conservation strategy for the collection of wild plant material for propagation, prioritizing mainly the endemic, rare, endangered, threatened and vulnerable plants of Europe found in different regions of Greece. Its aim is to contribute to the implementation of Target 8 of the Global and European Strategies for Plant Conservation at local, regional and international scales. In order to (i) define the ecological profile of the in situ requirements preferred and/or tolerated by each selected species, (ii) develop rapid and effective species-specific propagation protocols, and (iii) improve the cultivation of species of conservation concern in BBGK’s nurseries and ex situ conservation sections, geographical coordinates and in situ collection data obtained for each taxon were imported into a Geographic Information System environment (GIS). This information was then linked with several digital GIS thematic layers, including topographic, geological, edaphic, climatic, precipitation and temperature data derived from digital databases. Based on this approach, sexual and asexual propagation of plants from the Ionian Islands were conducted and rapid and effective baseline protocols were developed for 29 taxa (species and subspecies); four are presented here in detail and species-specific ex situ propagation and cultivation guidelines are given. Most of the taxa originating from the Ionian Islands were propagated by cuttings (55.2%) or seeds (34.5%), while the rest were propagated by root division at a rate from 1.7 to 2. The first round of propagation achieved a success rate ranging from 15 to 50% for 3 taxa, from 60 to 80% for 8 taxa and from more than 80 to 100% for 16 taxa, while the ex situ cultivation of the wild and propagated plant material has, so far, been successful. The application of GIS exemplified here presents a sensible and invaluable tool with a broad-scale potential in enhancing the prospects of the ex situ conservation of priority species collected from diverse environmental conditions in man-made habitats such as botanic gardens.     

Structure of a plant–flower-visitor network in the high-altitude sub-alpine desert of Tenerife, Canary Islands

Confined within a volcanic caldera at 2000 m a.s.l., the sub-alpine desert of Tenerife, Canary Islands, harbors a distinct biota. At this altitude the climate is harsh and the growing season short. Hence, plant and animal communities, constituting the sub-alpine plant–flower-visitor network, are clearly delimited, both spatially and temporally. We investigated species composition and interaction structure of this system. A total of 11 plant species (91% endemics) and 37 flower-visiting animal species (62% endemics) formed 108 interactions. Numbers of interactions among species varied ten-fold within both plant and animal communities. Generalization level of a species was positively correlated with its local abundance. Two separate network analyses revealed a significantly nested structure. In relation to a plant–flower-visitor system, nestedness implies that specialized species (animals or plants) interact with a subset of the species pool visiting (animals) or being visited (plants) by more generalized species. Therefore, specialized, locally rare plants tend to be visited by generalized, locally abundant animals, and specialized, locally rare animals tend to utilize generalized, locally abundant food plants. Such patterns could have implications for conservation of the sub-alpine network, and stress the importance of preserving not only rare species, but also the more abundant ones, which may be key food resources or pollinators in the plant–flower-visitor network.     

Functional groups of rare plants differ in levels of imperilment

Comparative examination of a large sample of plant species can reveal important aspects of life history that influence the ecology and distribution of taxa and their vulnerability to local extinction. We investigated whether functional groups of 71 rare plant species with contrasting life history traits differed in terms of population losses over time, regional range contraction, and range-wide levels of imperilment. Using town-level occurrence data from herbaria and Natural Heritage Program databases, we characterized species' extents of occurrence as α-hulls encompassing the centroids of New England towns that contained well-documented populations of these rare taxa. Family affiliation was used as a covariate in analyses to reduce phylogenetic bias. Disparate functional groups of plants differed both in proportions of populations lost and declines in range areas over time, with insect-pollinated taxa, upland (vs. wetland) taxa, species with localized seed dispersal modes, and taxa reaching their northern range boundary in New England significantly more imperiled than other functional groups. These techniques permit a broad comparative assessment of the distribution of large numbers of plant taxa, so that we can identify several functional groups that warrant more concerted conservation attention.     

Why are ferns regularly over‐represented on state and provincial rare plant lists?

Several recent studies have suggested that rare species are not randomly distributed throughout plant taxa. This would appear to apply to North American ferns, which are frequently over-represented on local lists of rare plant species. However, such lists often paint a skewed portrait of the true situation because of our tendency to recognize the rarity of well-known and charismatic species while ignoring that of lesser-known or less-appreciated species. In order to verify if this over-representation of ferns is a real and consistent trend throughout local floras in North America, we used data from what we consider to be the most complete and objective available database: NatureServe Explorer ( http://www.natureserve.org/explorer/ ). We compiled data on total vascular plant species, total fern species, as well as rare vascular plant species and rare fern species for each North American subnational (Canadian province or US state) flora. Rare species were defined as those belonging to one of NatureServe's 'at risk' categories. The null hypothesis that the contribution of rare ferns to total rare species did not differ from their contribution to the total vascular flora was assessed using χ². Out of 64 subnational floras, we obtained significantly higher values than expected in 28 cases, and significantly lower in only one case. Similar trends hold true for individual fern families. These tendencies could be related to several factors of anthropogenic, biological, climatological, evolutionary, and geographical origin. However, we believe that the main reason is related to scale, namely the geopolitical units at which rarity is often studied. Our results illustrate one of the problems of a parochial approach to conservation, where the perceived rarity of an entire taxon is exaggerated because of the scale at which rarity is addressed.     

Conservation challenges in a threatened hotspot: agriculture and plant biodiversity losses in Baja California,Mexico

Modern agricultural practices pose serious threats to biodiversity worldwide. Species losses from habitat conversion are well documented, but indirect impacts such as reduced water availability to adjacent ecosystems are less known. San Quintín is an important agricultural valley in the mediterranean climate region of Baja California, Mexico. The region is also a hotspot of plant species richness and endemism. Plant species in the region are here analyzed by comparison of the contemporary flora to historical botanical collections to identify extirpations. Historical collections indicate that habitat loss to agriculture has been a direct cause of species losses. As importantly, the unsustainable extraction of groundwater has apparently led to salt water intrusion, resulting in the loss of 22 native plant taxa, including 13 rare plants. Seventy-eight percent of all the vernal pool taxa have been lost from the flora (including 85 % of the rare taxa) and 11 % of plants of riparian and pond habitat (including 25 % of the rare taxa) are no longer found in the region. Unsustainable agricultural practices continue to threaten fragile coastal ecosystems and are a serious challenge to current and future conservation efforts. Ironically, these same practices frequently result in abandonment of cultivated areas. Owing to indirect impacts, conservation of biodiversity and large-scale agricultural operations are even less compatible on a regional scale than indicated by direct impacts. It is vital that sustainable agricultural practices be adopted locally and globally to avoid further losses of biodiversity.     

Drivers and interrelationships among multiple dimensions of rarity for freshwater fishes

Species can be rare or common in three different dimensions: geographic range size, habitat breadth, and local abundance. Understanding drivers of rarity are not only fundamentally interesting; it is also pertinent for their conservation. We addressed this challenge by analyzing the rarity of 291 native freshwater fishes occurring in ca 3500 independent stream reaches that span a broad environmental gradient across continental USA. Using phylogenetic regression and path analysis, we examined the concordance among the three rarity dimensions, and identified possible mechanisms by which species life‐history, habitat affinities, and biogeography drive variation in rarity. Weak double extinction jeopardies were driven by weakly positive correlations between habitat breadth and local abundance, and between habitat breadth and geographic range size. However, a triple extinction jeopardy was averted as local abundance and range size were not positively linked in our study. This is because large‐river and lacustrine habitat use mediated a trade‐off between local abundance and range size. Large rivers and lacustrine habitats represent important dispersal pathways and refugia that enabled fishes to acquire wide ranges; however, species using these habitats are less abundant overall because they are less adapted to small lotic channels, which comprise the majority of stream habitats in the US. Life‐history traits were key in governing the relationship between abundance and range size as large‐river and lacustrine habitat use were driven by body size, egg size, and parental care. Our analysis contributes novel insights into mechanisms that underlie multiple dimensions of rarity in freshwater fish and informs the prioritization of multiply rare species for conservation.     

Assessing extinction risk in the absence of species-level data: quantitative criteria for terrestrial ecosystems

The conservation of individual plant and animal species has been advanced greatly by the World Conservation Union’s (IUCN) development of objective, repeatable, and transparent criteria for assessing extinction risk, which explicitly separate the process of risk assessment from priority-setting. Here we present an analogous procedure for assessing the extinction risk of terrestrial ecosystems, which may complement traditional species-specific risk assessments, or may provide an alternative when only landscape-level data are available. We developed four quantitative risk criteria, derived primarily from remotely sensed spatial data, information on one of which must be available to permit classification. Using a naming system analogous to the present IUCN species-specific system, our four criteria were: (A) reduction of land cover and continuing threat, (B) rapid rate of land cover change, (C) increased fragmentation, and (D) highly restricted geographical distribution. We applied these criteria to five ecosystems covering a range of spatial and temporal scales, regions of the world, and ecosystem types, and found that Indonesian Borneo’s lowland tropical forests and the Brazilian Atlantic rainforest were Critically Endangered, while South Africa’s grasslands and Brazil’s Mato Grosso were Vulnerable. Furthermore, at a finer grain of analysis, one region of Venezuela’s coastal dry forests (Margarita Island) qualified as Vulnerable, while another (the Guasare River watershed) was Critically Endangered. In northern Venezuela, deciduous forests were classified as Endangered, semi-deciduous forests Vulnerable, and evergreen forests of Least Concern. We conclude that adoption of such a standardized system will facilitate globally comparable, repeatable geographic analyses that clearly separate risk assessment (a fundamentally scientific process), from the definition of conservation priorities, which should take into account additional factors, such as ecological distinctiveness, costs, logistics, likelihood of success, and societal preferences. Jon Paul Rodríguez and Jennifer K. Balch are contributed equally to this work     

Relationship between geographic rarity and perception of threat in Iberian butterflies

Measuring threat and selecting ??flagship?? species for conservation planning should ideally rely on ??dynamic?? criteria (i.e.: decreasing range and population sizes) which may not be available for most taxa and geographic regions. We address the question of what features of the organisms or of their geographic distributions lie behind selections of potentially threatened species when there is insufficient information on temporal trends. Focusing on Iberian butterflies, we evaluate the support for past and present lists of target species from the most easily quantifiable features of the species?? ranges and conspicuousness (size and visual apparency). Among the features tested, geographic rarity has the highest weight in all the species lists. However, the explanation is rather modest statistically, especially when the species selection is of a supra-regional nature (in this case European). Among the rarest species, those with geographic ranges concentrated in the study area (a) are comparatively few and (b) on average, have less restricted ranges than those whose geographic rarity results from their marginal occurrence in the study area. Finally, the total geographic coverage of the EU-threatened butterflies is relatively large in Iberia. As a consequence species-oriented conservation planning in this region may be rather unrealistic if only geographic rarity is emphasized, or if the levels of threat determined at the supra-regional (European) level are directly translated to the regional legislations. Thus we support the regionally hierarchical approach to conservation proposed by former authors.     

Hybridization-prone plant families do not generate more invasive species

Many plant taxa are both hybrid-derived and invasive, suggesting a causal connection. However, given that hybridization is not rare in plants, we should expect some fraction of invasive taxa to be hybrids, even in the absence of an underlying causal relationship. Here, we test the hypothesis that hybridization leads to invasiveness by asking whether the number of hybrids and the numbers of naturalized, weedy, and invasive taxa are correlated across 256 vascular plant families. Data were derived from six regional floras and three global databases listing weeds and invasives. To account for phylogenetic nonindependence, we combined a supertree analysis with phylogenetically independent contrasts. After correcting for family size and phylogeny, we conclude that vascular plant families with a higher propensity for hybridization are not more likely to produce more naturalized, weedy, or invasive species than families less prone to hybridization. Instead, hybridization-prone families were in some cases associated with fewer naturalized species and invaders. We present two hypotheses for these patterns, one based on Levin’s (Syst Bot 31:8–12, 2006) ideas on reproductive interference and another based on Darwin’s naturalization hypothesis. While these results do not preclude the possibility that hybridization generates weedy and invasive taxa with some frequency, they do suggest that the signal from the hybridization-invasion process may be relatively weak and easily obscured by other processes governing plant invasions.     

Prioritizing regionally rare plant species for conservation using herbarium data

Because the conservation of biodiversity occurs under time and resource constraints, it is necessary to prioritize species most deserving of attention. Natural history collections have been identified as a valuable source of information in applied conservation practice, particularly for species-rich taxa like plants. Here, online herbarium information was combined with a novel, straightforward priority setting approach to screen a large list of rare vascular plant species (n = 418) in Saskatchewan, Canada. Data was quantified to develop priority scores (for a given species) using three key criteria: (1) provincial responsibility in species survival, (2) species local population characteristics, and (3) the anthropogenic threats causing species to be rare. The use of a hierarchy of the three criteria, wherein provincial responsibility was assigned the most weight, resulted in the highest ranking for 13 species that exist only in Saskatchewan and no other Canadian province or territory. The list is a first step in identifying species deserving of conservation attention and/or further study, while the method itself was deemed to be highly relevant to conservation managers and decision makers due to its scale adaptability and fairly minimal resource requirements.     

Integrating the Rabinowitz rarity framework with a National Plant Inventory in South Korea

Increasingly large presence‐only survey datasets are becoming available for use in conservation assessments. Potentially, these records could be used to determine spatial patterns of plant species rarity and endemism. We test the integration of a large South Korean species record database with Rabinowitz rarity classes. Rabinowitz proposed seven classes of species rarity using three variables: geographic range, habitat specificity, and local population size. We estimated the range size and local abundance of 2,215 plant species from species occurrence records and habitat specificity as the number of landcover types each species’ records were found in. We classified each species into a rarity class or as common, compared species composition by class to national lists, and mapped the spatial pattern of species richness for each rarity class. Species were classed to narrow or wide geographic ranges using 315 km, the average from a range size index of all species (D_max), based on maximum distance between observations. There were four classes each within the narrow and wide range groups, sorted using cutoffs of local abundance and habitat specificity. Nationally listed endangered species only appeared in the narrow‐range classes, while nationally listed endemic species appeared in almost all classes. Species richness in most rarity classes was high in northeastern South Korea especially for species with narrow ranges. Policy implications. Large presence‐only surveys may be able to estimate some classes of rarity better than others, but modification to include estimates of local abundance and habitat types, could greatly increase their utility. Application of the Rabinowitz rarity framework to such surveys can extend their utility beyond species distribution models and can identify areas that need further surveys and for conservation priority. Future studies should be aware of the subjectivity of the rarity classification and that regional scale implementations of the framework may differ.