Three metrics of species diversity – species richness, the Shannon index and the Simpson index – are still widely used in ecology, despite decades of valid critiques leveled against them. Developing ...a robust diversity metric has been challenging because, unlike many variables ecologists measure, the diversity of a community often cannot be estimated in an unbiased way based on a random sample from that community. Over the past decade, ecologists have begun to incorporate two important tools for estimating diversity: coverage and Hill diversity. Coverage is a method for equalizing samples that is, on theoretical grounds, preferable to other commonly used methods such as equal‐effort sampling, or rarefying datasets to equal sample size. Hill diversity comprises a spectrum of diversity metrics and is based on three key insights. First, species richness and variants of the Shannon and Simpson indices are all special cases of one general equation. Second, richness, Shannon and Simpson can be expressed on the same scale and in units of species. Third, there is no way to eliminate the effect of relative abundance from estimates of any of these diversity metrics, including species richness. Rather, a researcher must choose the relative sensitivity of the metric towards rare and common species, a concept which we describe as ‘leverage.' In this paper we explain coverage and Hill diversity, provide guidelines for how to use them together to measure species diversity, and demonstrate their use with examples from our own data. We show why researchers will obtain more robust results when they estimate the Hill diversity of equal‐coverage samples, rather than using other methods such as equal‐effort sampling or traditional sample rarefaction.
We report the rediscovery of two species of rare snake in Espírito Santo state, Brazil: Aposto­lepis longicaudata Gomes, 1921 (also rare elsewhere in Brazil) and Drymoluber brazili (Gomes, ...1918). Apostolepis longicaudata has gone undetected in Espírito Santo for 66 years and Drymoluber brazili for 46 years. Espírito Santo state has only 10% of its forests remaining, and so the rediscovery of these forest‑dwelling species emphasizes the importance of small forest remnants for the conservation. These species have been assessed as Critically Endangered and Endangered in Espírito Santo state.
Managing and restoring tallgrass prairie ecosystem is an important form of pollinator conservation in the Midwestern United States. Prairie reconstruction has been found to enhance native bee ...diversity and abundance, but it is less clear if prairie reconstruction conserves species thought to be at-risk. We reanalyze a previously published dataset on the bee communities of reconstructed and remnant prairie in the US state of Minnesota to investigate how the abundance of at-risk species respond to local factors, such as floral diversity and prairie type (reconstructed or remnant), and landscape factors, in the form of surrounding agricultural production. We defined at-risk species in two ways. For bumble bees, we used the IUCN red list of bumble bees for North America. As other species in the bee community have not been systematically evaluated, we used an independent data set to calculate a community-level measure of rarity as a proxy for species risk. We calculated community rarity metrics using a Species Weighted Mean (SWM) approach, with species level rarity (relative abundance and site occurrence) derived from a regional dataset comprised of over 30,000 specimens from across the US state of Minnesota. We found that the declining bumble bee Bombus fervidus had higher abundances in remnant rather than reconstructed prairies. Floral richness was associated with rarer bee communities (lower SWM values) across remnant and reconstructed prairies. We show that planting and managing prairies for floral diversity promotes bee communities with rarer species, but that remnants better support some at-risk species such as Bombus fervidus.
Continental‐ and regional‐scale assessments of gaps in protected area networks typically use relatively coarse range maps for well documented species groups, creating uncertainty about the fate of ...unexamined biodiversity and providing insufficient guidance for land managers. By building habitat suitability models for a taxonomically diverse group of 2216 imperiled plants and animals, we revealed comprehensive and detailed protection opportunities in the conterminous United States. Summing protection‐weighted range‐size rarity (PWRSR, the product of the percent of modeled habitat outside of protected areas and the inverse of modeled habitat extent) uncovered novel patterns of biodiversity importance. Concentrations of unprotected imperiled species in places such as the northern Sierra Nevada, central and northern Arizona, the Rocky Mountains of Utah and Colorado, southeastern Texas, southwestern Arkansas, and Florida's Lake Wales Ridge have rarely if ever been featured in continental‐ and regional‐scale analyses. Inclusion of diverse taxa (vertebrates, freshwater mussels, crayfishes, bumble bees, butterflies, skippers, and vascular plants) partially drove these new patterns. When analyses were restricted to groups typically included in previous studies (birds, mammals, and amphibians), up to 53% of imperiled species in other groups were left out. The finer resolution of modeled inputs (990 m) also resulted in a more geographically dispersed pattern. For example, 90% of the human population of the conterminous United States lives within 50 km of modeled habitat for one or more species with high PWRSR scores. Over one‐half of the habitat for 818 species occurs within federally lands managed for biodiversity protection; an additional 360 species have over one‐half of their modeled habitat on federal multiple use land. Freshwater animals occur in places with poorer landscape condition but with less exposure to climate change than other groups, suggesting that habitat restoration is an important conservation strategy for these species. The results provide fine‐scale, taxonomically diverse inputs for local and regional priority‐setting and show that although protection efforts are still widely needed on private lands, notable gains can be achieved by increasing protection status on selected federal lands.
Species vulnerable to climate change face increased extinction risk, but many sensitive species may be overlooked due to limited data and exclusion from vulnerability assessments. Intrinsic ...sensitivity, or the inherent risk of species to environmental change due to biological factors, can be assessed with widely available data and may address gaps in multispecies vulnerability assessments. Species that exist in few places (geographically rare) and in fewer climates (smaller realized climate niche breadth) have high intrinsic sensitivity to environmental change. Using point occurrences, we systematically evaluated intrinsic sensitivity based on geographic rarity and realized climate niche breadth for 90 species of frogs and toads native to the United States using over 140,000 occurrence records. To relate sensitivity to perceived extinction risk, we compared intrinsic sensitivity to conservation status at state, federal, and international levels. We found no relationship between intrinsic sensitivity and federal or state conservation status, and some intrinsically sensitive species (i.e., those with small areas of occurrence and narrow climate specificity) were not listed as at risk at any level. Intrinsic sensitivity analysis can serve as an early warning system for species that may be currently at risk and overlooked.
To pursue growth, luxury brands are expanding their markets, but such expansion puts their exclusivity at risk. To offset this threat, leading luxury brands systematically increase their average ...prices, such that their profitability depends on luxury consumers’ sustained acceptance of high prices. This pricing strategy requires luxury brands to determine why some luxury consumers believe luxury must be expensive, as well as assess the relative weights of their motivations to adopt this belief. A cross-country, covariance-based, causal analysis of the antecedents of the belief reveals the same hierarchy of motivations. Overall, extrinsic motivations dominate intrinsic motivations in both Western and Asian cultures and in mature and emerging countries. Unexpectedly, the pursuit of high quality is not a driver. This result creates a dilemma for luxury brand communications, which tend to emphasize high quality and craftsmanship, because of the concerns associated with a strong reliance on extrinsic motivations.
The global market for luxury brands has witnessed sustained growth in the last two decades, driven by purchases from emerging economies such as China and rising upper middle classes. Because luxury ...is associated with rarity and exclusivity, fears arise about whether continued growth might dilute the leading luxury brands' desirability. Prior studies offer conflicting results about the effect of greater market penetration on luxury brands' desirability; it appeared negative in the USA but not in Asia, today's highest growth luxury markets. The present research analyzes 3200 luxury consumers' perceptions of 60 major brands across six Eastern and Western countries, both emerging and mature. The overall effect of increased market penetration on luxury desirability remains negative, while the impact of awareness remains always positive. This confirmation of the rarity principle has notable implications for marketing luxury brands that seek to sustain their dream value.
Aim
Geodiversity underpins biodiversity, but the contribution of specific geofeatures or landforms has rarely been explored. In this study, we use multiple vascular plant species diversity measures ...on alpha, beta and gamma levels to explore the linkage between biodiversity and co‐located landforms (e.g. gullies, dunes and lake shores). We hypothesize that biodiversity will be positively related to geodiversity, which is founded on distinct landforms. Additionally, we propose that different landforms will sustain different amounts of biodiversity and that high alpha and gamma diversity values are related to landform‐driven moisture availability whereas high beta diversity relates especially to landform‐specific microtopographic variation.
Location
Rokua UNESCO Global Geopark area, Finland.
Taxon
Vascular plants.
Methods
We compare vascular plant species richness measures, Shannon's and Simpson's diversity indices, rarity‐weighted richness and local contribution to beta diversity at altogether three levels of biodiversity (alpha, beta and gamma) for different landforms. Landform information is compiled from aerial photos, spatial data layers and targeted field surveys. We compare results to control habitat (i.e. sites without any distinct landforms) within the study area.
Results
Vascular plant diversity was higher on landforms than in control habitat. There was also notable variation between species diversity of different landforms. Moisture‐rich gullies and river shores were especially diverse at all three levels, whereas aapa mires hosted most unique species composition (highest beta diversity). Beta diversity patterns were rather comparable with alpha and gamma diversity patterns, which contradict our hypothesis.
Main conclusions
This study quantitatively established a strong connection between terrestrial plant communities and multiple landforms. Our results highlighted the landform‐controlled variation in soil moisture, microclimate and microtopography in enhancing plant species diversity. Based on the results, we promote the inclusion of landform‐based geodiversity information in conservation management and in further biogeographical studies.
Understanding the interplay between rarity and vulnerability in the decline and extinction of species is a major challenge for modern conservation biology. In addition to traditional approaches, ...answering this question necessarily requires integrating new methodologies and information on species' life-history traits and responses to environmental stressors. Here we use data for over 4000 mammal species to: (1) assess which forms and levels of rarity are most represented across current IUCN threat categories; (2) test whether interspecific variation in vulnerability is more closely linked to intrinsic traits related to their rarity, or to extrinsic factors related to anthropogenic pressures; and (3) identify geographical areas where species with high potential vulnerability are particularly common and assess their overlap with forecasts of land cover change. To achieve these goals, we model the directional influence of life-history traits related with rarity and extrinsic correlates on vulnerability. Our results confirm the strong link between rarity and vulnerability within mammalian orders. A model encompassing the three main rarity traits (i.e. range size, population density, and habitat breadth) correlates with vulnerability, despite not being directly correlated with population density. Recent habitat changes (within the past 35 years) did not show a direct relationship with vulnerability, but the contractions in range size reveal a more complex long-term effect on species vulnerability. Given the current scenario of limited conservation resources, we anticipate that knowledge about the characteristics most associated with vulnerability, coupled with mapping species possessing these traits and facing potential future land changes, can facilitate the development of more precise and effective conservation strategies aimed at preventing species extinctions.
•Rarity and vulnerability are intertwined, posing a significant challenge for conservation biology.•Understanding traits linked to species vulnerability aids in creating effective conservation plans with limited resources.•Intrinsic traits related to rarity strongly influence interspecific variation in vulnerability in mammals.•Global areas with high potential vulnerability for mammals are identified, considering forecasts of land cover change.
Indigenous Peoples are long‐term custodians of their lands, but only recently are their contributions to conservation starting to be recognized in biodiversity policy and practice. Tropical forest ...loss and degradation are lower in Indigenous lands than unprotected areas, yet the role of Indigenous Peoples' Lands (IPL) in biodiversity conservation has not been properly assessed from regional to global scales. Using species distribution ranges of 11,872 tropical forest‐dependent vertebrates to create area of habitat maps, we identified the overlap of these species ranges with IPL and then compared values inside and outside of IPL for species richness, extinction vulnerability, and range‐size rarity. Of assessed vertebrates, at least 76.8% had range overlaps with IPL, on average overlapping ~25% of their ranges; at least 120 species were found only within IPL. Species richness within IPL was highest in South America, while IPL in Southeast Asia had highest extinction vulnerability, and IPL in Dominica and New Caledonia were important for range‐size rarity. Most countries in the Americas had higher species richness within IPL than outside, whereas most countries in Asia had lower extinction vulnerability scores inside IPL and more countries in Africa and Asia had slightly higher range‐size rarity in IPL. Our findings suggest that IPL provide critical support for tropical forest‐dependent vertebrates, highlighting the need for greater inclusion of Indigenous Peoples in conservation target‐setting and program implementation, and stronger upholding of Indigenous Peoples' rights in conservation policy.
We identified areas of habitat of tropical forest‐dependent mammals, amphibians, birds, and reptiles across the tropics and examine the extent of overlap with Indigenous Peoples' Lands (IPL). We also compared values inside and outside of IPL for species richness, extinction vulnerability, and range‐size rarity at the country level. We found that at least 76.8% of vertebrate species had ranges overlapping IPL, with 120 species found only within IPL. Compared to the 10 km buffer outside IPL, 51% of countries had higher species richness, 58% had lower extinction vulnerability, and 40% had higher range‐size rarity inside IPL.
PDF
