scholarly journals The commonness of rarity: Global and future distribution of rarity across land plants

2019 ◽  
Vol 5 (11) ◽  
pp. eaaz0414 ◽  
Author(s):  
Brian J. Enquist ◽  
Xiao Feng ◽  
Brad Boyle ◽  
Brian Maitner ◽  
Erica A. Newman ◽  
...  
Keyword(s):  
Plant Species ◽  
Conservation Planning ◽  
Rare Species ◽  
Extinction Risk ◽  
Large Fraction ◽  
Neutral Theory ◽  
Species Abundance ◽  
Risk Assessments ◽  
Human Land Use ◽  
Species Abundance Distributions

A key feature of life’s diversity is that some species are common but many more are rare. Nonetheless, at global scales, we do not know what fraction of biodiversity consists of rare species. Here, we present the largest compilation of global plant diversity to quantify the fraction of Earth’s plant biodiversity that are rare. A large fraction, ~36.5% of Earth’s ~435,000 plant species, are exceedingly rare. Sampling biases and prominent models, such as neutral theory and the k-niche model, cannot account for the observed prevalence of rarity. Our results indicate that (i) climatically more stable regions have harbored rare species and hence a large fraction of Earth’s plant species via reduced extinction risk but that (ii) climate change and human land use are now disproportionately impacting rare species. Estimates of global species abundance distributions have important implications for risk assessments and conservation planning in this era of rapid global change.

scholarly journals The commonness of rarity: Global and future distribution of rarity across land plants

2019 ◽  
Author(s):  
Brian Joseph Enquist ◽  
Xiao Feng ◽  
Bradley Boyle ◽  
Brian Maitner ◽  
Erica A. Newman ◽  
...  
Keyword(s):  
Plant Species ◽  
Rare Species ◽  
Large Fraction ◽  
Neutral Theory ◽  
Species Abundance ◽  
Land Plant ◽  
Observation Data ◽  
Heavy Tailed Distributions ◽  
Species Abundance Distributions ◽  
Heavy Tailed

A key feature of life’s diversity is that some species are common but many more are rare. Nonetheless, at global scales, we do not know what fraction of biodiversity consists of rare species. Here, we present the largest compilation of global plant species observation data in order to quantify the fraction of Earth’s extant land plant biodiversity that is common versus rare. Tests of different hypotheses for the origin of species commonness and rarity indicates that sampling biases and prominent models such as niche theory and neutral theory cannot account for the observed prevalence of rare species. Instead, the distribution of commonness is best approximated by heavy-tailed distributions like the Pareto or Poisson-lognormal distributions. As a result, a large fraction, ~36.5% of an estimated ~435k total plant species, are exceedingly rare. We also show that rare species tend to cluster in a small number of ‘hotspots’ mainly characterized by being in tropical and subtropical mountains and areas that have experienced greater climate stability. Our results indicate that (i) non-neutral processes, likely associated with reduced risk of extinction, have maintained a large fraction of Earth’s plant species but that (ii) climate change and human impact appear to now and will disproportionately impact rare species. Together, these results point to a large fraction of Earth’s plant species are faced with increased chances of extinction. Our results indicate that global species abundance distributions have important implications for conservation planning in this era of rapid global change.

Explaining the excess of rare species in natural species abundance distributions

Nature ◽  
2003 ◽  
Vol 422 (6933) ◽  
pp. 714-716 ◽  
Author(s):  
Anne E. Magurran ◽  
Peter A. Henderson
Keyword(s):  
Rare Species ◽  
Species Abundance ◽  
Species Abundance Distributions

scholarly journals Towards a unification of niche and neutral models of community ecology

2018 ◽  
Author(s):  
Andres Laan ◽  
Gonzalo G. de Polavieja
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Community Dynamics ◽  
Neutral Theory ◽  
Species Abundance ◽  
Theory Model ◽  
Niche Theory ◽  
Species Abundance Distributions ◽  
Restoring Forces ◽  
Neutral Models

AbstractEcological models of community dynamics fall into two main categories. The neutral theory of biodiversity correctly predicts various large-scale ecosystem characteristics such as the species abundance distributions. On a smaller scale, the niche theory of species competition explains population dynamics and interactions between two to a dozen species. Despite the successes of the two theories, they rely on two contradictory assumptions. In the neutral theory each species is competitively equivalent while in the niche theory every species is specialized to exploit a specific part of its environment. Here we propose a resolution to this contradiction using a game theory model of competition with an attractor hyperplane as its equilibrium solution. When the population dynamics shifts within the hyperplane, it is selectively neutral. However, any movement perpendicular to the hyperplane is subject to restoring forces similar to what is predicted by the niche theory. We show that this model correctly reproduces empirical species abundance distributions and is also compatible with species removal experiments.

scholarly journals The Dynamic Hypercube as a Niche Community Model

2021 ◽  
Vol 9 ◽  
Author(s):  
John M. Halley ◽  
Stuart L. Pimm
Keyword(s):  
Community Dynamics ◽  
Neutral Theory ◽  
Species Abundance ◽  
Ecological Communities ◽  
Evolutionary Time ◽  
Community Model ◽  
Theory Of Island Biogeography ◽  
Species Abundance Distributions ◽  
Hypercube Model ◽  
Zero Sum

Different models of community dynamics, such as the MacArthur–Wilson theory of island biogeography and Hubbell’s neutral theory, have given us useful insights into the workings of ecological communities. Here, we develop the niche-hypervolume concept of the community into a powerful model of community dynamics. We describe the community’s size through the volume of the hypercube and the dynamics of the populations in it through the fluctuations of the axes of the niche hypercube on different timescales. While the community’s size remains constant, the relative volumes of the niches within it change continuously, thus allowing the populations of different species to rise and fall in a zero-sum fashion. This dynamic hypercube model reproduces several key patterns in communities: lognormal species abundance distributions, 1/f-noise population abundance, multiscale patterns of extinction debt and logarithmic species-time curves. It also provides a powerful framework to explore significant ideas in ecology, such as the drift of ecological communities into evolutionary time.

scholarly journals Understanding how biodiversity unfolds through time under neutral theory

2016 ◽  
Vol 371 (1691) ◽  
pp. 20150226 ◽  
Author(s):  
Olivier Missa ◽  
Calvin Dytham ◽  
Hélène Morlon
Keyword(s):  
Species Richness ◽  
Dynamic Equilibrium ◽  
Neutral Theory ◽  
Species Abundance ◽  
Ecological Systems ◽  
Biodiversity Patterns ◽  
Species Abundance Distributions ◽  
Species Area ◽  
The Difference ◽  
Time Required

Theoretical predictions for biodiversity patterns are typically derived under the assumption that ecological systems have reached a dynamic equilibrium. Yet, there is increasing evidence that various aspects of ecological systems, including (but not limited to) species richness, are not at equilibrium. Here, we use simulations to analyse how biodiversity patterns unfold through time. In particular, we focus on the relative time required for various biodiversity patterns (macroecological or phylogenetic) to reach equilibrium. We simulate spatially explicit metacommunities according to the Neutral Theory of Biodiversity (NTB) under three modes of speciation, which differ in how evenly a parent species is split between its two daughter species. We find that species richness stabilizes first, followed by species area relationships (SAR) and finally species abundance distributions (SAD). The difference in timing of equilibrium between these different macroecological patterns is the largest when the split of individuals between sibling species at speciation is the most uneven. Phylogenetic patterns of biodiversity take even longer to stabilize (tens to hundreds of times longer than species richness) so that equilibrium predictions from neutral theory for these patterns are unlikely to be relevant. Our results suggest that it may be unwise to assume that biodiversity patterns are at equilibrium and provide a first step in studying how these patterns unfold through time.

scholarly journals Global shortfalls in extinction risk assessments for endemic flora

2020 ◽  
Author(s):  
R. V. Gallagher ◽  
S. Allen ◽  
M. C. Rivers ◽  
A. P. Allen ◽  
N. Butt ◽  
...  
Keyword(s):  
Plant Species ◽  
Endemic Species ◽  
Extinction Risk ◽  
Plant Conservation ◽  
Well Being ◽  
Global Strategy ◽  
Risk Assessments ◽  
Face Threats ◽  
Extinction Risk Assessment ◽  
Endemic Flora

SUMMARYThe Global Strategy for Plant Conservation (GSPC) ambitiously calls for an assessment of extinction risk for all recognised plant taxa by 20201. It is now clear that this target will not be met in the short-term; only 21-26% of known plant species have been assessed2 – a monumental shortfall in anticipated knowledge. Yet the need for risk assessments has never been more urgent. Plants are rapidly going extinct3,4 and face threats such as climate change5 and permanent deforestation6. Extinction risk assessments continue to provide the critical foundation to inform protection, management and recovery of plant species7,8, the loss of which will have clear consequences for maintaining planetary systems and human well-being9. Here, we rank countries of the world based on progress towards assessing the extinction risk to their endemic flora. Overall, 67% of country-based endemic species do not have an extinction risk assessment completed (143,294 species). We show that some of the world’s wealthiest nations, which also have relatively strong species protections, are failing to protect their unique flora by not systematically assessing risks to their endemic species.

scholarly journals Brazilian efforts towards achieving a comprehensive extinction risk assessment for its known flora

Rodriguésia ◽  
2018 ◽  
Vol 69 (4) ◽  
pp. 1529-1537 ◽  
Author(s):  
Eline Martins ◽  
Gustavo Martinelli ◽  
Rafael Loyola
Keyword(s):  
Plant Species ◽  
Extinction Risk ◽  
Plant Conservation ◽  
Global Strategy ◽  
Risk Assessments ◽  
Huge Amount ◽  
Good Path ◽  
Reliable Assessment ◽  
Extinction Risk Assessment ◽  
Made In

Abstract Brazil houses nearly 36,400 native terrestrial plant species. The country is a signatory of the Global Strategy for Plant Conservation (GSPC) and has to develop tools to achieve GSPC targets. Target 2 states that countries must undertake risk assessments of its entire known plant species by 2020. Here, we offer a panorama on how far has Brazil gone towards achieving this target. We compiled data on all risk assessments for plant species ever made in the country and produced the first synthesis of results with respect to these assessments. We found that the Brazilian Red List Authority for plants has assessed the extinction risk of 5,646 species so far, which corresponds to 15.5% of all known flora in Brazil. Among these species, 2,738 (48%) are currently threatened. Those species are distributed across all Brazilian Biomes and states. Families with the highest number of threatened species are Asteraceae and Bromeliaceae. We conclude that Brazil is far from achieving GSPC target 2 by 2020. However, given the enormous flora of the country and the huge amount of effort and resources put into this particular task, Brazil is following a good path towards a reliable assessment of it entire flora.

scholarly journals To clean or not to clean: Cleaning open‐source data improves extinction risk assessments for threatened plant species

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Connor T. Panter ◽  
Rosemary L. Clegg ◽  
Justin Moat ◽  
Steven P. Bachman ◽  
Bente B. Klitgård ◽  
...  
Keyword(s):  
Open Source ◽  
Plant Species ◽  
Extinction Risk ◽  
Risk Assessments ◽  
Threatened Plant ◽  
Open Source Data ◽  
Threatened Plant Species ◽  
Source Data

scholarly journals Fuzzy Quantification of Common and Rare Species in Ecological Communities (FuzzyQ)

2020 ◽  
Author(s):  
Juan A. Balbuena ◽  
Clara Montlleó ◽  
Cristina Llopis-Belenguer ◽  
Isabel Blasco-Costa ◽  
Volodimir L. Sarabeev ◽  
...  
Keyword(s):  
Rare Species ◽  
Clustering Algorithm ◽  
Species Abundance ◽  
R Package ◽  
Ecological Communities ◽  
Wide Range ◽  
Species Abundance Distributions ◽  
The Common ◽  
Spatio Temporal ◽  
The Impact

Abstract1. Most species in ecological communities are rare whereas only a few are common. This distributional paradox has intrigued ecologists for decades but the interpretation of species abundance distributions remains elusive.2. We present Fuzzy Quantification of Common and Rare Species in Ecological Communities (FuzzyQ) as an R package. FuzzyQ shifts the focus from the prevailing species-categorization approach to develop a quantitative framework that seeks to place each species along a rare-commonness gradient. Given a community surveyed over a number of sites, quadrats, or any other convenient sampling unit, FuzzyQ uses a fuzzy clustering algorithm that estimates a probability for each species to be common or rare based on abundance-occupancy information. Such as probability can be interpreted as a commonness index ranging from 0 to 1. FuzzyQ also provides community-level metrics about the coherence of the allocation of species into the common and rare clusters that are informative of the nature of the community under study.3. The functionality of FuzzyQ is shown with two real datasets. We demonstrate how FuzzyQ can effectively be used to monitor and model spatio-temporal changes in species commonness, and assess the impact of species introductions on ecological communities. We also show that the approach works satisfactorily with a wide range of communities varying in species richness, dispersion and abundance currencies.4. FuzzyQ produces ecological indicators easy to measure and interpret that can give both clear, actionable insights into the nature of ecological communities and provides a powerful way to monitor environmental change on ecosystems. Comparison among communities is greatly facilitated by the fact that the method is relatively independent of the number of sites or sampling units considered. Thus, we consider FuzzyQ as a potentially valuable analytical tool in community ecology and conservation biology.

scholarly journals Emergent neutrality in consumer-resource dynamics

2019 ◽  
Author(s):  
Rafael D’Andrea ◽  
Theo Gibbs ◽  
James P. O’Dwyer
Keyword(s):  
Community Dynamics ◽  
Neutral Theory ◽  
Species Abundance ◽  
Natural World ◽  
Biodiversity Patterns ◽  
Interspecific Differences ◽  
Community Turnover ◽  
Species Abundance Distributions ◽  
Resource Dynamics ◽  
Taxonomic Groups

AbstractNeutral theory assumes all species and individuals in a community are ecologically equivalent. This controversial hypothesis has been tested across many taxonomic groups and environmental contexts, and successfully predicts species abundance distributions across multiple high-diversity communities. However, it has been critiqued for its failure to predict a broader range of community properties, particularly regarding community dynamics from generational to geological timescales. Moreover, it is unclear whether neutrality can ever be a true description of a community given the ubiquity of interspecific differences, which presumably lead to ecological inequivalences. Here we derive analytical predictions for when and why non-neutral communities of consumers and resources may present neutral-like outcomes, which we verify using numerical simulations. Our results, which span both static and dynamical community properties, demonstrate the limitations of summarizing distributions to detect non-neutrality, and provide a potential explanation for the successes of neutral theory as a description of macroecological pattern.Author SummaryThe neutral theory of biodiversity assumes that species are ecologically equivalent. Given the natural history observation of ubiquitous phenotypic differences between species, it is surprising that neutral theory has successfully predicted a broad range of biodiversity patterns, and simultaneously unsurprising that these results have not convinced ecologists that the natural world is neutral. However, we have lacked a description of how neutrality can emerge in a natural way from ecological mechanisms and species differences. Our study sheds light on this question, providing a theoretical backdrop for the success of neutral theory as a description of macroecological pattern. We derive a prediction for the degree to which consumers must differ in preferences for different resources before the resulting biodiversity patterns become distinguishable from neutrality. These predictions, which we confirm using simulations, show that neutral-like outcomes are possible even when resource requirements across consumers are very far from neutral. Our results can be tested in experimental microbial communities, where, equipped with an inferred consumption network, our analysis can yield predictions for biodiversity patterns and community turnover at different taxonomic levels.

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