Search

ABSTRACT Aim A great deal of information on distribution and diversity can be extracted from presence-absence matrices (PAMs), the basic analytical tool of many biogeographic studies. This paper presents numerical procedures that allow the analysis of such information by taking advantage of mathematical relationships within PAMs. In particular, we show how range-diversity (RD) plots summarize much of the information contained in the matrices by the simultaneous depiction of data on distribution and diversity. Innovation We use matrix algebra to extract and process data from PAMs. Information on the distribution of species and on species richness of sites is computed using the traditional R (by rows) and Q (by columns) procedures, as well as the new Rq (by rows, considering the structure of columns) and Qr (by columns, considering the structure by rows) methods. Matrix notation is particularly suitable for summarizing complex calculations using PAMs, and the associated algebra allows the implementation of efficient computational programs. We show how information on distribution and species richness can be depicted simultaneously in RD plots, allowing a direct examination of the relationship between those two aspects of diversity. We explore the properties of RD plots with a simple example, and use null models to show that while parameters of central tendency are not affected by randomization, the dispersion of points in RD plots does change, showing the significance of patterns of co-occurrence of species and of similarity among sites. Main conclusion Species richness and range size are both valid measures of diversity that can be analysed simultaneously with RD plots. A full analysis of a system requires measures of central tendency and dispersion for both distribution and species richness. [ABSTRACT FROM AUTHOR]

We describe a spatially explicit simulation experiment designed to assess relative impacts of macroecological traits on patterns of biological diversification under changing environmental conditions. Using a simulation framework, we assessed impacts of species' niche breadth (i.e., the range of their abiotic tolerances) and dispersal ability on resulting patterns of speciation and extinction and evaluated how these traits, in conjunction with environmental change, shape biological diversification. Simulation results supported both niche breadth and dispersal ability as important drivers of diversification in the face of environmental change, and suggested that the rate of environmental change influences how species interact with the extrinsic environment to generate diversity. Niche breadth had greater effects on speciation and extinction than dispersal ability when climate changed rapidly, whereas dispersal ability effects were elevated when climate changed slowly. Our simulations provide a bottom-up perspective on the generation and maintenance of diversity under climate change, offering a better understanding of potential interactions between species' intrinsic macroecological characteristics and a dynamic extrinsic environment in the process of biological diversification. [ABSTRACT FROM AUTHOR]

We sought to determine if the global distribution of sea anemones (cnidarian order Actiniaria) conforms to the classic pattern of biogeography--taxon richness at the equator with attenuation toward the poles--a pattern that is derived almost entirely from data on terrestrial plants and animals. We plotted the empirical distribution of species occurrences in 10° bands of latitude based on published information, then, using the Chao2 statistic, inferred the completeness of that inventory. We found the greatest species richness of sea anemones at 30-40° N and S, with lower numbers at tropical latitudes and the fewest species in polar areas. The Chao2 statistic allowed us to infer that the richness pattern we found is not due to particularly poor knowledge of tropical sea anemones. No 10° band of latitude has less than 60% of the theoretical number of species known, but for only about half of them could we reject the null hypothesis (P = 0.05) that information is complete; anemone diversity is best documented at high latitudes. We infer that the 1089 valid species currently known constitute about 70% of the theoretical total of about 1500 species of Actiniaria. The distribution pattern of sea anemone species resembles that of planktonic foraminiferans and benthic marine algae, although planktonic bacteria, marine bivalves, and shallow and deep scleractinian corals show the terrestrial pattern of equatorial richness attenuating with latitude. Sea anemone species richness is complementary to that of scleractinian corals at many scales; our findings affirm it at the global scale. [ABSTRACT FROM AUTHOR]

We present a global conservation analysis for an entire "flagship"taxon, land mammals. A combination of rarity, anthropogenic impacts, andpolitical endemism has put about a quarter of terrestrial mammalspecies, and a larger fraction of their populations, at risk ofextinction. A new global database and complementarity analysis forselecting priority areas for conservation shows that ∼11% of Earth'sland surface should be managed for conservation to preserve at least 10%of terrestrial mammal geographic ranges. Different approaches, fromprotection (or establishment) of reserves to countryside biogeographicenhancement of human-dominated landscapes, will be required to approachthis minimal goal. [ABSTRACT FROM AUTHOR]

Aim: Migratory species depend on various habitats and resources along their migration routes. Characteristics such as dependence on distinct habitats and the presence of multiple threats along their migratory routes make these species vulnerable, and gaps in knowledge about their ecology and migration processes make them difficult to conserve. Urania boisduvalii is a diurnal moth endemic to Cuba that feeds on plants of Omphalea spp. during its larval phases. These plants produce secondary metabolites as a defence against the moth's larvae, which then are forced to migrate. Although some ecological aspects of Urania boisduvalii are known, its migration routes remain largely unknown. This research proposes potential migratory routes of Urania boisduvalii among populations of its host plant. Location: Cuba. Methods: We developed ecological niche models of the moth and its hosts based on environmental, anthropic, biotic and biogeographic factors to obtain potential distributional areas that include zones where positive interactions are found but exclude those where negative factors are present. These areas were overlapped to hypothesize potential breeding areas for the moths. Potential migratory corridors were proposed based on environmental connectivity. Results: The moth and its hosts have broad potential distributions; however, limiting factors have substantially reduced these areas, especially for plants. The potential migratory routes of Urania boisduvalii are complex and mostly involve the western and eastern regions of Cuba. Most records outside potential breeding areas were close to these migratory corridors. Main conclusions: We offer initial hypotheses of the migratory routes of U. boisduvalii, which may be useful to guiding monitoring projects that can provide more definitive views of the seasonal distribution of this species across the Cuban archipelago. [ABSTRACT FROM AUTHOR]

Pollinators are currently the focus of international concern, as numerous studies have documented declines in their diversity and abundance. Pollinator conservation has therefore become an international priority. We selected 815 pollinator species (including bats, bees, hummingbirds, and hawkmoths) inhabiting the southern United States, Mexico and part of Central America to assess the overlap between their distributions and land-use changes. We also analyzed the representativeness values of species contained within current protected areas (PAs). Then, we considered three important pressures —habitat loss, population density and infrastructure, and crop-specific pesticides— to determine high-priority and complementary conservation areas to optimize the long-term protection of these species. We found strong overlap (74.5 %) between the distributions of pollinator species and areas with a moderate or high degree of human modification. Furthermore, current PAs are both insufficient and inefficient: they cover only 14.3 % of the study area and represent on average 14.6 ± 8.6 % of the species' total distribution area. For 62.7 % of the species, <15 % of their distribution occurred within PAs. This picture is particularly alarming for the most range-restricted and threatened species. If our prioritization were implemented, the protection coverage would increase to 30 % (in line with the post-2020 Global Biodiversity Framework), substantially increase representativeness values, and cover over 25 % of the ranges of all species. In the context of the current biodiversity crisis, we provide insights about where transboundary efforts should focus to design a PA network that is effective for the conservation of whole biodiversity, including important ecosystem processes. • There is an important degree of overlap between pollinators' distribution and current human-modified areas. • Existing protected areas in North America only cover ~15% of species ranges. • For over half of pollinator species, less than 15% of their whole distribution area falls within protected areas. • We identified important opportunities to improve species representativeness values based on the post-2020 Global Biodiversity • It is imperative that policymakers promote policies to reduce pesticide uses and protect the high-priority areas identified here. [ABSTRACT FROM AUTHOR]

To protect threatened species, iNaturalist, one of the most important repositories of geographic information on species' geographic distributions, deliberately adds uncertainty to otherwise precise occurrence records of threatened species. This "clouded" or "cloaked" information is shared with other biodiversity repositories, such as the Global Biodiversity Information Facility (GBIF). Although a mechanism exists by which users can obtain unbiased information, it requires the user to ask each data owner for the exact location of the record, which is difficult as many data providers may have participated in assembling the currently available data. To test for effects of adding uncertainty in estimation of the ecological niche and the potential distribution, we modeled the climatic requirements of three amphibian species using five sets of records: (i) a set of records at full accuracy and precision, and (ii) the same records but with 25 %, 50 %, 75 % and 100 % of biased occurrences induced by applying the iNaturalist protocol for introducing biases into biodiversity records. The three species present contrasting distribution sizes (from micro-endemic to widely distributed in the Sierras Pampeanas Centrales in Argentina). By employing ecological niche models, we showed that inducing bias generates misleading estimates of geographic distributions and ecological requirements even in situations in which the percentage of biased information is "low." We also evaluated the percentage of occurrence records of IUCN-threatened vertebrates in GBIF provided by iNaturalist, and found that, for 2011 to present, the majority of GBIF records comes from this citizen science repository. These results could have relevant implications for conservation strategies. This effect accentuates the Wallacean and Hutchinsonian shortfalls, which are already some of the most significant impediments to developing effective conservation strategies. The iNaturalist data-cloaking initiative certainly will aid in protecting some threatened species, but could prove harmful to others. We encourage researchers to consider the precision and accuracy of the occurrence data used in their analyses, and we urge iNaturalist to simplify procedures by which credible researchers can access the full-accuracy data. • iNaturalist adds uncertainty to otherwise precise occurrence records of IUCN Red List of threatened species. • Using niche models, we assessed the effects of the iNaturalist protocol for introducing biases to occurrence records. • From 2011 to the present most of the GBIF available occurrences of IUCN-threatened vertebrates are provided by iNaturalist. • iNaturalist manipulations change the range of the species significantly in both geographic and environmental spaces. • Researchers should consider the precision and accuracy of the occurrence data used in their analyses. [ABSTRACT FROM AUTHOR]

Species invasions represent a significant dimension of global change yet the dynamics of invasions remain poorly understood and are considered rather unpredictable. We explored interannual dynamics of the invasion process in the Eurasian collared dove (Streptopelia decaocto) and tested whether the advance of the invasion front of the species in North America relates to centrality (versus peripherality) within its estimated fundamental ecological niche. We used ecological niche modelling approaches to estimate the dimensions of the fundamental ecological niche on the Old World distribution of the species, and then transferred that model to the New World as measures of centrality versus peripherality within the niche for the species. Although our hypothesis was that the invasion front would advance faster over more favourable (i.e. more central) conditions, the reverse was the case: the invasion expanded faster in areas presenting less favourable (i.e. more peripheral) conditions for the species as it advanced across North America. This result offers a first view of a predictive approach to the dynamics of species' invasions, and thereby has relevant implications for the management of invasive species, as such a predictive understanding would allow better anticipation of coming steps and advances in the progress of invasions, important to designing and guiding effective remediation and mitigation efforts. [ABSTRACT FROM AUTHOR]

Blonder et al. (, Global Ecology and Biogeography, 23, 595-609) introduced a new multivariate kernel density estimation (KDE) method to infer Hutchinsonian hypervolumes in the modelling of ecological niches. The authors argued that their KDE method matches or outperforms several methods for estimating hypervolume geometries and for conducting species distribution modelling. Further clarification, however, is appropriate with respect to the assumptions and limitations of KDE as a method for species distribution modelling. Using virtual species and controlled environmental scenarios, we show that KDE both under- and overestimates niche volumes depending on the dimensionality of the dataset and the number of occurrence records considered. We suggest that KDE may be a viable approach when dealing with large sample sizes, limited sampling bias and only a few environmental dimensions. [ABSTRACT FROM AUTHOR]

Aim Determining which species are more prone to extinction is vital for conserving Earth's biodiversity and for providing insight into macroevolutionary processes. This paper utilizes the Pliocene to Recent fossil record of mollusks to identify determinants of species' extinction over the past three million years of Earth history. Location Western Atlantic. Methods We focus on 92 bivalve and gastropod species that lived during the mid-Pliocene Warm Period ( mPWP; ∼3.264-3.025 Ma) and have either since gone extinct or are still extant. We used ecological niche modeling ( ENM) to assess the vulnerability of these species to extinction as a function of both fundamental ( FN) and realized ( RN) niche breadth proxies, geographic range size, and amount of suitable area available to them during the Last Glacial Maximum ( LGM; ∼21 Ka). Results Geographic range size emerged as a key predictor of extinction for the studied mollusk species, with RN breadth and amount of suitable area available during the LGM as secondary predictors. By contrast, FN breadth was not a significant predictor of extinction risk. Main conclusions The failure to recover FN breadth as a predictor of extinction may suggest that extinction resistance is achieved when species are more successful in filling the geographic extent of their fundamental tolerances. That is, when it comes to species' survival, being a generalist or specialist sensu stricto may be secondary to the unique historical, dispersal, and biotic constraints that dictate a species' occupation of suitable environments, and consequently of geographic space, at a particular time. Identifying the factors that promote extinction is important because of the time-intensive nature of estimating extinction risk for individual species and populations, and because of the rising concerns about the future of marine ecosystems and biodiversity. [ABSTRACT FROM AUTHOR]

Decisionmakers need updated, scientifically sound and relevant information to implement appropriate policy measures and make innovative commitments to halt biodiversity loss and improve human well-being. Here, we present a recent science-based synthesis on the biodiversity and ecosystem services of Mexico, intended to be a tool for policymakers. We describe the methodological approach used to undertake such an assessment and highlight the major findings. Organized into five volumes and originally written in Spanish (Capital Natural de México), it summarizes the available knowledge on the components, structure, and functioning of the biodiversity of Mexico; the threats and trajectories of anthropogenic impact, together with its conservation status; and the policies, institutions, and instruments available for its sustainable management. We stress the lessons learned that can be useful for similar exercises in other megadiverse developing countries and identify major gaps and strategic actions to conserve the natural capital in light of the challenges of the Anthropocene. [ABSTRACT FROM AUTHOR]

Geographic distributions of species are constrained by several factors acting at different scales, with climate assumed to be a major determinant at broad extents. Recent studies, however, have challenged this statement and indicated that climate may not dominate among the factors governing geographic distributions of species. Here, we argue that these results are misleading due to the lack of consideration of the geographic area that has been accessible to the species. North America. We generated null distributions for 75 North American endemic and 19 non-endemic bird species. For each species, climatic envelopes of observed and null distributions were modelled using neural networks and generalized linear models, and seven climatic predictors. Values of the area under the receiver-operating characteristic curve (AUC) based on models of observed distributions were compared with corresponding AUC values for the null distributions. More than 82% of the endemic species showed AUC higher for the observed than for the null distributions, while 63% of the non-endemic species showed such a pattern. We demonstrate a dominant climatic signal in shaping North American bird distributions. Our results attest to the importance of climate in determining species distributions and support the use of climate-envelope models for estimating potential distributional areas at the appropriate spatial scales. [ABSTRACT FROM AUTHOR]

The diversity of sites and the distribution of species are fundamental pieces in the analysis of biogeographic and macroecological questions. A link between these two variables is the correlation between the species diversity of sites and the mean range size of species occurring there. Alternatively, one could correlate the range sizes of species and the mean species diversity within those ranges. Here we show that both approaches are mirror images of the same patterns, reflecting fundamental mathematical and biological relationships. We develop a theory and analyze data for North American mammals to interpret range-diversity plots in which the species diversity of sites and the geographic range of species can be depicted simultaneously. We show that such plots contain much more information than traditional correlative approaches do, and we demonstrate that the positions of points in the plots are determined to a large extent by the average, minimum, and maximum values of range and diversity but that the dispersion of points depends on the association among species and the similitude among sites. These generalizations can be applied to biogeographic studies of diversity and distribution and in the identification of hotspots of diversity and endemism. [ABSTRACT FROM AUTHOR]

Evaluating potential routes of invasion of pathogens and vectors of sanitary importance is essential for planning and decision-making at multiple scales. An effective tool are process-explicit models that allow coupling environmental, demographic and dispersal information to evaluate population growth and range dynamics as a function of the abiotic conditions in a region. In this work we simulate multiple dispersal/invasion routes in Mexico that could be taken by ambrosia beetles and a specific symbiont, Harringtonia lauricola, responsible for a severe epiphytic of Lauraceae in North America. We used Xyleborus bispinatus Eichhoff 1868 as a study subject and estimated its demography in the laboratory in a temperature gradient (17, 20, 26, 29, 35 °C), which we then used to parameterize a process-based model to estimate its metapopulation dynamics. The maximum intrinsic growth rate of X. bispinatus is 0.13 with a thermal optimum of 26.2 °C. The models suggest important regions for the establishment and dispersal the states of Veracruz, Chiapas and Oaxaca (high host and secondary vectors diversity), the Isthmus of Tehuantepec (connectivity region), and Michoacán and Jalisco (important avocado plantations). The use of hybrid process-based models is a promising tool to refine the predictions applied to the study of biological invasions and species distributions., (© 2024. The Author(s).)

In this work, Grinnellian niche theory (a body of theory about geographic distributions of species in terms of noninteracting niche variables) is used to demonstrate that species-area relationships emerge with both size of environmental space and size of geographic area. As environmental space increases, more species' fundamental niches are included, thus increasing the number of species capable of living in the corresponding region. This idea is made operational by proposing a size measure for multidimensional environmental space and approximating fundamental niches with minimum volume ellipsoids. This framework allows estimating a presence-absence matrix based on the distribution of fundamental niches in environmental space, from which many biodiversity measures can be calculated, such as beta diversity. I establish that Whittaker's equation for beta diversity is equivalent to MacArthur's formula relating species numbers and niche breadth; this latter equation provides a mechanism for the species-niche space relationship. I illustrate the theoretical results via exploration of niches of the terrestrial mammals of North America (north of Panama). Each world region has a unique structure of its environmental space, and the position of fundamental niches in niche space is different for different clades; therefore, species-area relationships depend on the clades involved and the region of focus, mostly as a function of MacArthur's niche beta diversity. Analyzing species-area relationships from the perspective of niche position in environmental space is novel, shifting emphasis from demographic processes to historical, geographic, and climatic factors; moreover, the Grinnellian approach is based on available data and is computationally feasible.

The latitudinal diversity gradient (LDG), where the number of species increases from the poles to the Equator, ranks among the broadest and most notable biodiversity patterns on Earth. The pattern of species-rich tropics relative to species-poor temperate areas has been recognized for well over a century, but the generative mechanisms are still debated vigorously. We use simulations to test whether spatio-temporal climatic changes could generate large-scale patterns of biodiversity as a function of only three biological processes-speciation, extinction and dispersal-omitting adaptive niche evolution, diversity-dependence and coexistence limits. In our simulations, speciation resulted from range disjunctions, whereas extinction occurred when no suitable sites were accessible to species. Simulations generated clear LDGs that closely match empirical LDGs for three major vertebrate groups. Higher tropical diversity primarily resulted from higher low-latitude speciation, driven by spatio-temporal variation in precipitation rather than in temperature. This suggests that spatio-temporal changes in low-latitude precipitation prompted geographical range disjunctions over Earth's history, leading to high rates of allopatric speciation that contributed to LDGs. Overall, we show that major global biodiversity patterns can derive from interactions of species' niches (fixed a priori in our simulations) with dynamic climate across complex, existing landscapes, without invoking biotic interactions or niche-related adaptations.

The Convention on the Conservation of Migratory Species of Wild Animals (CMS) is a Multilateral Environmental Agreement (MEA) focused on species that regularly travel across international borders. Despite covering an important group of species, CMS is under-utilized compared to other conservation-focused MEAs. CMS suffers from a lack of participation across North America and most of Asia. Our goal is to illustrate differences in species richness and average range-size across signatory and nonsignatory nation-states using range-diversity plots. We also show differences in the cost of CMS membership relative to species patterns to highlight which countries may be discouraged from becoming CMS signatories. Despite containing many CMS species, large economies such as the United States, Russia, and China are not members of the convention. To facilitate migratory species conservation into the future, CMS should seek to fill gaps in participation, potentially directing recruitment efforts toward nonsignatory states that would receive the largest benefit at the lowest relative cost.

We analyze the invasive potential of two Asian ambrosia beetles, Xyleborus glabratus and Euwallacea sp., into Mexico and the southern United States. The fungal symbionts of these beetles have been responsible for damage to trees of the family Lauraceae, including Persea americana and other non-cultivated tree species on both coasts of the United States. We estimate their potential threat using ecological niche modeling and spatial multi-criteria evaluation protocols to incorporate plant and beetle suitabilities as well as forest stress factors across Mexico. Mexico contains higher climatic and habitat suitability for X. glabratus than for Euwallacea sp. Within this country, the neotropical region is most vulnerable to invasion by both of these species. We also identify a corridor of potential invasion for X. glabratus along the Gulf of Mexico coast where most Lauraceae and native Xyleborus species are present; dispersal of either X. glabratus or Euwallacea sp. into this region would likely lead to major disease spread. However, the overall potential damage that these beetles can cause may be a function of how many reproductive hosts and how many other ambrosia beetles are present, as well as of their capacity to disperse. This work can also alert relevant managers and authorities regarding this threat.

At a global level, the relationship between biodiversity importance and capacity to manage it is often assumed to be negative, without much differentiation among the more than 200 countries and territories of the world. We examine this relationship using a database including terrestrial biodiversity, wealth and governance indicators for most countries. From these, principal components analysis was used to construct aggregated indicators at global and regional scales. Wealth, governance, and scientific capacity represent different skills and abilities in relation to biodiversity importance. Our results show that the relationship between biodiversity and the different factors is not simple: in most regions wealth and capacity varies positively with biodiversity, while governance vary negatively with biodiversity. However, these trends, to a certain extent, are concentrated in certain groups of nations and outlier countries. We discuss our results in the context of collaboration and joint efforts among biodiversity-rich countries and foreign agencies.

Estimating actual and potential areas of distribution of species via ecological niche modeling has become a very active field of research, yet important conceptual issues in this field remain confused. We argue that conceptual clarity is enhanced by adopting restricted definitions of "niche" that enable operational definitions of basic concepts like fundamental, potential, and realized niches and potential and actual distributional areas. We apply these definitions to the question of niche conservatism, addressing what it is that is conserved and showing with a quantitative example how niche change can be measured. In this example, we display the extremely irregular structure of niche space, arguing that it is an important factor in understanding niche evolution. Many cases of apparently successful models of distributions ignore biotic factors: we suggest explanations to account for this paradox. Finally, relating the probability of observing a species to ecological factors, we address the issue of what objects are actually calculated by different niche modeling algorithms and stress the fact that methods that use only presence data calculate very different quantities than methods that use absence data. We conclude that the results of niche modeling exercises can be interpreted much better if the ecological and mathematical assumptions of the modeling process are made explicit.

To assess the completeness of a floristic or faunal inventory, one may use the ratio of the observed number of species to the "true number" of species (C). If the inventory is complete, C =1. The estimate of the true number can be obtained from accumulation curves, nonparametric methods, or other techniques. We devised a simple method for computing confidence intervals (CI) for C and for evaluating the null hypothesis that the inventory is complete. The method is based on the assumptions that an estimate of the variance of the true number of species is known and that the distribution of the estimator of the true number of species is approximately normal. We applied our method to bird inventories in the Balsas Basin of Mexico. The completeness index for subtransects were lower (84.0, 85.4, and 89.9%) than for the whole transect (91.6%) (all significantly different from 100%). Thus, these particular inventories were incomplete at 2 spatial resolutions. Our method of estimating CI for C can be used to estimate species richness obtained from databases of different sites or to test the null hypothesis that an inventory derived from a database is complete.

Recently, advances in information technology and an increased willingness to share primary biodiversity data are enabling unprecedented access to it. By combining presences of species data with electronic cartography via a number of algorithms, estimating niches of species and their areas of distribution becomes feasible at resolutions one to three orders of magnitude higher than it was possible a few years ago. Some examples of the power of that technique are presented. For the method to work, limitations such as lack of high-quality taxonomic determination, precise georeferencing of the data and availability of high-quality and updated taxonomic treatments of the groups must be overcome. These are discussed, together with comments on the potential of these biodiversity informatics techniques not only for fundamental studies but also as a way for developing countries to apply state of the art bioinformatic methods and large quantities of data, in practical ways, to tackle issues of biodiversity management.