Red List Assessments Research Articles

Begonia littoralis (Begoniaceae), a new species from North Coast of São Paulo State, Brazil

Field research in Submontane Ombrophilous Atlantic Forest in the extreme North Coast of São Paulo State, bordering Rio de Janeiro, has brought us the knowledge of a new species of Begonia (Begoniaceae). The new species is here compared with Begonia erythrobracteata and Begonia fluminensis, by having similar leaf blades which are glabrous adaxially. Description, taxonomic comments, map, photographic plates, illustrations and a provisional IUCN Red List Assessment are provided.

Notes on cauliflory, sexual dimorphism and biogeography in Drypetes (Putranjivaceae, Malpighiales) and a taxonomic treatment for D. gabonensis and two new cauliflorous threatened species from Central Africa, D. aphanes sp. nov. and D. cauta sp. nov.

We present a preliminary discussion about cauliflory, sexual dimorphism and biogeographic patterns in Drypetes Vahl (Putranjivaceae Endl.), focused on Africa. We also present a taxonomic treatment for two new species of cauliflorous trees of this genus from the rainforests of western Central Africa, one endemic to Gabon and known from six gatherings, D. aphanes Quintanar, D.J.Harris & Barberá sp. nov., and the other distributed in Gabon and the Republic of the Congo, D. cauta D.J.Harris, Barberá & Quintanar sp. nov., also known from another six gatherings. They are presented along with D. gabonensis Pierre ex Hutch., known from 25 gatherings made throughout western Central Africa, a species with markedly dimorphic flowers between sexes compared to the rest of the species in the genus. Specimens of these two new species have been confused with D. gabonensis due to some morphological resemblances. This treatment includes the detailed descriptions of these three species, the typification of their names, a comparative table summarizing their main morphological differences, an identification key, an illustration and information about their habitat and distribution. A provisional IUCN Red List assessment shows that D. gabonensis and D. cauta sp. nov. are ‘Vulnerable’ species, and D. aphanes sp. nov. is ‘Endangered’. After the publication of these new species, Drypetes consists of 86 species in continental Africa and the Malagasy Region and 219 species for the whole world.

Assessment of recovery potential for the American horseshoe crab (Limulus polyphemus): An application of the IUCN green status process

Abstract According to an International Union for Conservation of Nature (IUCN) Red List assessment (RLA), the American horseshoe crab (Limulus polyphemus), an iconic coastal species, is at risk of extirpation in some regions within its range where small and vulnerable populations occur. However, the RLA does not consider future status beyond viability and does not attempt to identify the conservation necessary to effectively mitigate threats and recover the species to full ecological functionality. To aid in conservation planning for vulnerable species, the IUCN developed the Green Status of Species assessment (GSA) process to complement the RLA. This paper describes the application of the GSA process to assess the recovery potential of the American horseshoe crab. First, specific Limulus populations within spatial units for conservation were delineated, and their statuses were defined based on viability and ecological functionality. Then conservation actions were identified that would promote recovery and affect their near‐ and long‐term population status under different conservation scenarios. Horseshoe crab conservation has relied on, and will continue to depend on, effective harvest regulation. However, as currently conceived, conservation is not expected to mitigate habitat loss at the scale required to restore range‐wide ecological functionality, primarily because habitat loss is widespread and affected by climate change. Thus, the GSA results, while indicating that there is potential for near‐term recovery gains, reveal that long‐term recovery is in doubt owing to expected loss of habitat. To conserve critical habitats for spawning and early life stages and achieve ecological functionality, it is imperative to identify and develop conservation plans at appropriate spatial scales. Unfortunately, such plans do not currently exist and need to be established. The GSA Green Score can then serve as a metric for monitoring recovery and gauging the effectiveness of conservation implementation.

Red List for British seaweeds: evaluating the IUCN methodology for non-standard marine organisms

The IUCN Red List of Threatened Species is an authoritative tool in biodiversity conservation. Whilst IUCN criteria have been applied successfully to groups such as birds and mammals, a Red List assessment of British seaweeds in 2021 revealed that the categories to which seaweed species were assigned were dependent on how the criteria were applied. Here, this seaweed assessment is used as a case study with which to evaluate the IUCN methodology for use with ‘non-standard’ groups of organisms. A data-driven assessment of red (Rhodophyta), green (Chlorophyta) and brown (Phaeophyceae) seaweeds, which applied three (A, B and D) of the five IUCN criteria (A–E), categorized 13% of 617 British species as threatened. Following peer review, only 7% of species were categorized as threatened (1% Critically Endangered—CR, 3% Endangered—EN, 3% Vulnerable—VU), and 55% as Data Deficient. This reduction in species categorized as threatened suggests that strict application of the IUCN criteria may, at least for the seaweeds, over-estimate threat. As a result of this assessment, recommendations include the need for a more unified monitoring system and a review of the suitability for/application of the IUCN assessment criteria to some types of organisms. For example, in clonal populations, it is not possible to count individuals, and complex life histories cause additional complications. IUCN criteria must be applicable to a wide range of organisms, including seaweeds.

On the discovery of new sub-populations of <i>Bentinckia nicobarica</i> (Kurz) Becc. (Arecaceae) in Andaman Islands,India: Mapping and updated red list assessment

Bentinckia nicobarica (Kurz) Becc., a threatened palm is known to be strictly endemic to the Nicobar group of Islands as per IUCN Red list assessment 1998. It grows in the lowland rainforests close to the coastlines and fairly distributed all over in Nicobar group of Islands except Great Nicobar. Recently, new natural sub-populations of this species have been discovered from Alexandra Island, Boat Island, Hopeday Island, Redskin Island, Tarmugli Island and coast of Wandoor, South Andaman. The IUCN guideline has been used for the reassessment of its threat status which will help in prioritizing conservation.

Assessing the extinction risks of amphibians impacted by infectious diseases

Emerging infectious diseases (EIDs) are a major threat to amphibians worldwide. Determining the extinction risk of species susceptible to EIDs is challenging because of data limitations, especially in the initial stages of emergence and spread of disease. The fast rate of spread of many EIDs makes it necessary to assess the extinction risk of impacted host species before detailed mechanistic (epidemiological) or correlative (ecological niche) models can be developed. We present a simple method for identifying species that are at the highest risk of extinction due to an EID. Our method incorporates projections of the spatial spread of disease into IUCN Red List assessments under criteria A3 (based on future population reductions), D2 (plausible future threats), and E (probability of extinction). We apply this method to assess the extinction risk of salamander species in Europe susceptible to population declines caused by Batrachochytrium salamandrivorans (Bsal), the agent of the salamander plague. Our results indicate a high risk of extinction for European salamanders as a result of the spreading Bsal infection. Depending on the rate of spread from the current Bsal localities, and the emergence of new localities through human travel and transport, the number of species threatened by Bsal can range from a few to almost 30 of the 40 species that occur in Europe. Our method allows preliminary assessments of extinction risk based on limited information. For species at risk of extinction due to fast-spreading EIDs, it provides a pragmatic and precautionary solution until more realistic models can be developed.

Red list assessments of Chinese higher plants

ABSTRACT Based on the two most recent assessments of Chinese higher plants in 2013 and 2020, of 34,450 and 39,330 species, respectively, we analysed the threatened status of Chinese higher plants. In 2020, around 4,088 (10.39%) of the assessed species in China are threatened, 2,875 (7.31%) Near Threatened, 27,593 (70.16%) not currently threatened and categorised as Least Concern and 4,752 (12.08%) categorised as Data Deficient. While in 2013, 3,767 (10.93%) of the assessed higher plants in China are threatened, 2,723 (7.90%) Near Threatened, 24,296 (70.53%) Least Concern and 3,612 (10.48%) Data Deficient. Estimates of the Red List Index in the two years show different patterns when using different weighting methods with the equal steps weighting method showing a slight decrease (0.91675–0.91495) and the extinction risk weighting method showing a slight increase (0.98792–0.98797). We inferred that China’s threatened plant species were likely / relatively effectively protected. However, attention should also be given to the non-threatened species in the future as an additional strategy for their conservation, to maintain their non-threatened status.

The ocean sunfishes (family Molidea): Recommendations from the IUCN molidae review panel

The ocean sunfishes (family Molidae) include the largest and heaviest bony fishes in the world and species within the family are distributed from southern Chile to the Arctic Circle. The Molidae currently contains five species within three genera: Mola mola (Linnaeus, 1758), Mola alexandrini (Ranzani, 1839), Mola tecta (Nyegaard et al., 2017), Masturus lanceolatus (Liénard, 1840) and Ranzania laevis (Pennant, 1776). Recent conservation concerns led to a re-examination of the IUCN Red List classifications, where three species had previously ranged from Least Concern to Vulnerable, and two species had yet to be assessed. To better support conservation of these fishes on a global scale, the IUCN Molidae review panel was formed to update these listings. This panel, supported by experts from the IUCN Red List assessment process, included participants from the UK, Portugal, Taiwan, New Zealand, Japan and USA. The central objective was to consolidate recent research and policy expertise and assess urgent conservation issues facing the ocean sunfishes. A summary is presented here alongside key recommendations.

Combining trends from disparate monitoring programs to inform Red List assessments: The case of the Cape Vulture (Gyps coprotheres)

Conservation decisions are often informed by Red List assessments, which are substantially influenced by estimated population trends. Population trend estimates used by Red List assessments should therefore be as quantitative, comprehensive, and transparent as possible. We combine counts of breeding pairs of the Cape Vulture (Gyps coprotheres) that occur at separate breeding colonies and span differing time periods. The methodological concept is simple: transform time series into interannual rates of change, put those rates into a year-by-series matrix, then average that matrix to estimate the interannual population wide rate of change. Our analysis uses state-space models and basic arithmetic to estimate interannual rates of change per time series. Analyses are performed under a Bayesian framework to ensure that uncertainty is propagated into a composite index that estimates the percent global population reduction over three generations. Our results indicate that the global Cape Vulture population declined by 25 % (95 % CRI = 0.5 %–44 %) from 1977 to 2019. Such a decline suggests the species should be listed as Near Threatened under Criterion A2, instead of Vulnerable, as the species is currently listed. However, we performed a sensitivity analysis that suggested the species might indeed be Vulnerable if unmonitored colonies are in decline. Although the analysis for each species and time series should be customized, we suggest that the general practice of averaging the interannual rates of change for all available time series could improve qualitative estimates of population reduction used in many Red List assessments.

Plantago tunetana (Plantaginaceae) in Tunisia: notes on its morphology, distribution, and ecology

A review of the available knowledge for the Tunisian-Algerian endemic Plantago tunetana is proposed in the present work. This narrowly endemic species was hitherto known from Tunisia within a very restricted area. Field surveys of its occurrence during the last few years, within its locus classicus, allow to find only one population in Gouraïa locality in north-western Tunisia. IUCN Red List assessment shows that the species could be considered as Critically Endangered and requires the implementation of immediate appropriate measurements to ensure its conservation. Besides, an identification key to subgenera, sections, series and species of the genus Plantago in Tunisia is provided.

Camera Traps Uncover the Behavioral Ecology of an Endemic, Cryptic Monkey Species in the Congo Basin.

Guenons are the most diverse clade of African primates, and many species living within the core of the Congo Basin rainforest are still understudied. The recently described guenon species, Cercopithecus lomamiensis, known as lesula, is a cryptic, semi-terrestrial species endemic to the central Congo Basin in the Democratic Republic of the Congo. The recent IUCN Red List Assessment recognizes lesula's risk of extinction in the wild as Vulnerable. The objective of our study was to use camera traps to expand knowledge on the behavioral ecology of lesula. We conducted three systematic, terrestrial camera trap (CT) surveys within Lomami National Park and buffer zone (Okulu: 2013; Losekola: 2014; E15: 2015). We accumulated 598 independent events of lesula over 5960 CT days from 92 CTs. Typical of Cercopithecus species, camera trap videos reveal that lesula has a diurnal activity pattern, birth seasonality, a group size of up to 32 individuals, and social organization with female philopatry and male dispersal. Results also suggest that lesula are highly terrestrial, distinguishing them from other Cercopithecus species, which are mostly arboreal. Our study provides new information about the behavioral ecology of this little-studied primate, generating species-specific knowledge of a threatened species for successful conservation planning.

The rediscovery of Impatiens sigmoidea Hook. f. (Balsaminaceae) in Guizhou, China after more than 100 years

Impatiens sigmoidea was described in 1908 by the eminent British plant taxonomist J. D. Hooker based on specimens collected by the French missionaries E. M. Bodinier et al. from Guizhou, China. However, there has been no other records since then. After years of concern, we rediscovered I. sigmoidea in one of its type localities, Gao-po Town, in 2018. A revised description, colour photographs and a provisional IUCN Red List assessment of this species are provided, along with discussions of its geographical distribution, ecology and morphological comparison with I. lasiophyton. The lectotype of I. sigmoidea is also designated here. The rediscovery provides an essential basis for enriching the botanical resources of the genus Impatiens.

A matter of warts: a taxonomic treatment for Drypetes verrucosa (Putranjivaceae, Malpighiales) and a new cauliflorous species from Cameroon and Nigeria, D. stevartii

Background and aims – Specimens of a new tree species in the genus Drypetes (Putranjivaceae) distributed in Cameroon and eastern Nigeria, D. stevartii, were associated with D. verrucosa, another tree species endemic to Gabon, due to its warty fruits and to the overall morphological resemblances of both species. Material and methods – The present study is based on the study of 20 gatherings of D. verrucosa and 26 gatherings of D. stevartii. Morphological observations on herbarium specimens belonging to the new species and D. verrucosa were carried out in order to describe them. Key results – This treatment includes the detailed descriptions of these two species, the typification of their names, a comparative table summarizing their main morphological differences, an identification key, photographs of both, as well as information about their distribution, habitat, and phenology. Preliminary IUCN Red List assessments show that both D. verrucosa and D. stevartii are ‘Near Threatened’ species.

Amphibians of Rwanda: Diversity, Community Features, and Conservation Status

The diversity and distribution of the amphibians in Rwanda was critically reviewed to provide a reliable species inventory for informed conservation management. The checklist of the amphibian species of Rwanda is based on results of our own fieldwork, historical records compiled from the literature, and examination of voucher specimens in museum collections. A total of 62 species are recorded, and 22 further species listed in field guides and open-access data bases are discussed, identified as erroneous records, and consequently not included in the country list. We provide diagnostic characters of external morphology and the advertisement call for each validated species, and a short synopsis of geographic distribution, altitudinal range, occurrence in the provinces of Rwanda, and habitat preference. We provide keys to all genera, and all taxonomically described species based on morphological characters and additional keys based on features of the advertisement calls. We discuss features of amphibian communities including local community structure and delimitation of altitudinal metacommunities. Based on the IUCN red list assessment and our field surveys, we propose for the first time a national red list of amphibians in Rwanda.

Modeling mammal response to fire based on species' traits.

Fire has shaped ecological communities worldwide for millennia, but impacts of fire on individual species are often poorly understood. We performed a meta-analysis to predict which traits, habitat, or study variables and fire characteristics affect how mammal species respond to fire. We modeled effect sizes of measures of population abundance or occupancy as a function of various combinations of these traits and variables with phylogenetic least squares regression. Nine of 115 modeled species (7.83%) returned statistically significant effect sizes, suggesting most mammals are resilient to fire. The top-ranked model predicted a negative impact of fire on species with lower reproductive rates, regardless of fire type (estimate = -0.68), a positive impact of burrowing in prescribed fires (estimate = 1.46) but not wildfires, and a positive impact of average fire return interval for wildfires (estimate = 0.93) but not prescribed fires. If a species' International Union for Conservation of Nature Red List assessment includes fire as a known or possible threat, the species was predicted to respond negatively to wildfire relative to prescribed fire (estimate = -2.84). These findings provide evidence of experts' abilities to predict whether fire is a threat to a mammal species and the ability of managers to meet the needs of fire-threatened species through prescribed fire. Where empirical data are lacking, our methods provide a basis for predicting mammal responses to fire and thus can guide conservation actions or interventions in species or communities.

The effect of sampling effort and methodology on range size estimates of poorly-recorded species for IUCN Red List assessments

Geographic range size is the most commonly implemented criterion of species’ extinction risk used in IUCN Red List assessments, especially for poorly-recorded species. IUCN applies two contrasting range size measures to capture different facets of a species’ distribution: Extent of Occurrence (EOO; Criterion B1) is the area bounding all known occurrences and is a proxy for the spatial autocorrelation of risk, while the Area of Occupancy (AOO; Criterion B2) is the area occupied within this boundary and is related to population size at finer grains. Various methods have been proposed to measure both EOO and AOO. We evaluate the impact of applying four methods for each of Criterion B1 and of B2, as well as key parameter choices, on the Red List status of 227 poorly-recorded neotropical pteridophyte species. Between 2 and 100% of species would be considered threatened depending on methodology. The minimum convex polygon method of estimating EOO was relatively robust to sampling effort for all but the least-recorded species. The IUCN-recommended method for estimating AOO of summing occupied 2 × 2 km grid cells was very strongly correlated with the total number of records. It is likely that only a small fraction of species can be adequately assessed using this method, and we recommend caution applying the method to poorly-recorded species in particular, where models predicting occupancy in unsampled areas (e.g. species distribution models) may provide more accurate assessments. It is vital that methodological information is retained with assessments, and comparisons should only be made between assessments utilising equivalent methods.

Bidens wailele (Asteraceae: Coreopsideae): A New Critically Endangered Species from Kauai, Hawaiian Islands

Premise of research. The explosive diversification of Hawaiian Bidens is considered one of the premier examples of plant adaptive radiation in the native Hawaiian flora. Botanical exploration, especially in remote areas, continues and sometimes results in the discovery of new species. Most of these new discoveries are narrowly distributed endemics, and some are evaluated to be threatened or endangered, sometimes critically so, as is the case for Bidens wailele.Methodology. Bidens wailele K.R. Wood & Knope (Asteraceae/Compositae) is (1) described and illustrated from Kauai, Hawaiian Islands; we also (2) provide a diagnostic key distinguishing characters that separate B. wailele from all other native Kauai Bidens, (3) present a summary of its distribution, ecology, and threats; and (4) provide a formal Red List assessment utilizing the International Union for Conservation of Nature (IUCN) criteria for endangerment. This discovery is part of ongoing floristic research and exploration conducted by the National Tropical Botanical Garden Science and Conservation Department.Pivotal results. This new species occurs in extremely wet conditions around the waterfalls of Waialeale and Wainiha, central Kauai. Morphologically, it is most similar to Bidens valida, a Kauai endemic species naturally occurring around windswept ridges and cliffs of southeastern Kauai (as on Haupu, Hulua, and Kahili Mountains).Conclusions. This rare new species is presently known from only 700–800 individuals and restricted to three remote locations; B. wailele has been evaluated under the IUCN Red List criteria and proposed as critically endangered. A fourth population on a wet cliff where the new species historically occurred (i.e., Kamanu, Kauai) was destroyed by a landslide after its discovery in 2008, most likely caused by torrential rains and demonstrating the species’ vulnerability for extinction.

Cognitive biases can play a role in extinction assessments: The case of the Caspian tiger

The premature declaration of a species as extinct has been reported across different taxonomic groups and is commonly referred to as Romeo’s error or the Lazarus effect. In this study, based on a review of historical records and testimonies from local communities, we review the case of Caspian tiger (Panthera tigris virgata), a species we consider was prematurely declared globally extinct in 1950s. Considering that compelling evidence which suggests that Caspian tigers existed in Turkey perhaps up until early 1990s (some 40 years after international scientific community considered the species extinct) it is reasonable to posit that conservationists missed a historical opportunity to save the species. The case of the Caspian tiger demonstrates the cognitive bias of the Dunning-Kruger effect in action and the potential implications for conservation experts who are engaged in remotely evaluating contemporary species distributions. To mitigate these factors when assessing the global status of species threatened by extinction, we suggest that increased awareness of this type of cognitive bias could facilitate the introduction of additional measures in relevant conservation initiatives and in IUCN Red List assessments. For example, the formation of independent and specific teams to unearth implicit assumptions and weaknesses in assessments, and to question the group thinking of the species assessors. Against the backdrop of the current unprecedented rapid biodiversity decline, we recommend that researchers should be alert of the cognitive biases involved in species assessments and in conservation at large.

Red List of lichenized fungi in Bulgaria

The first Red List assessment of lichenized fungi reported from Bulgaria is presented. The IUCN Red List criteria were applied to 138 species to assess their current extinction risk and to highlight the main threats for them. Our results revealed that six species are Regionally Extinct (RE), 23 species are Critically Endangered (CR), 20 species are Endangered (EN), 13 species are Vulnerable (VU), 11 species are Near Threatened (NT), 58 species are Least Concern (LC), and seven species are Data Deficient (DD). The most important floristic regions for lichen conservation are the Pirin Mts (26 species), the Balkan Range (25), the Rila Mts (25), the Rhodopes (20), Mt. Vitosha (16), Mt. Strandzha (16), and the Black Sea coast (15). The main threats are development of tourism and recreation activities that destroy habitats (60 species affected), air pollution (55), climate change (53), development of tourism and recreation areas (41), harvesting trees and other woody vegetation (unintentional effects) (27), ecosystem modifications that convert or degrade habitats (18), and development of housing and urban areas (14). The information provided in this Red List will assist to further develop the national conservation strategy for Bulgaria.

Globba amicitia (Zingiberaceae: Globbeae), a new species from Phou Khao Khouay National Protected Area, Bolikhamxay Province, Laos

Globba amicitia (Zingiberaceae: Globbeae), a new species from Laos is described and illustrated. This species is morphologically most similar to G. larsenii, a species from Thailand, in having erect inflorescences and entirely yellow flowers without spots, but easily recognizable by its sessile cincinni and puberulent lateral staminodes. A proposed IUCN Red List assessment and notes on distinguishing characters are provided. A key to species of Globba subgenus Globba in the Indo-Chinese region is included.