Center for Global Change and Sustainability

BACKGROUND: Ecological niche modeling is a set of analytical tools with applications in diverse disciplines, yet creating these models rigorously is now a challenging task. The calibration phase of these models is critical, but despite recent attempts at providing tools for performing this step, adequate detail is still missing. Here, we present the kuenm R package, a new set of tools for performing detailed development of ecological niche models using the platform Maxent in a reproducible way. RESULTS: This package takes advantage of the versatility of R and Maxent to enable detailed model calibration and selection, final model creation and evaluation, and extrapolation risk analysis. Best parameters for modeling are selected considering (1) statistical significance, (2) predictive power, and (3) model complexity. For final models, we enable multiple parameter sets and model transfers, making processing simpler. Users can also evaluate extrapolation risk in model transfers via mobility-oriented parity (MOP) metric. DISCUSSION: Use of this package allows robust processes of model calibration, facilitating creation of final models based on model significance, performance, and simplicity. Model transfers to multiple scenarios, also facilitated in this package, significantly reduce time invested in performing these tasks. Finally, efficient assessments of strict-extrapolation risks in model transfers via the MOP and MESS metrics help to prevent overinterpretation in model outcomes.

Tropical forests disappear rapidly because of deforestation, yet they have the potential to regrow naturally on abandoned lands. We analyze how 12 forest attributes recover during secondary succession and how their recovery is interrelated using 77 sites across the tropics. Tropical forests are highly resilient to low-intensity land use; after 20 years, forest attributes attain 78% (33 to 100%) of their old-growth values. Recovery to 90% of old-growth values is fastest for soil (<1 decade) and plant functioning (<2.5 decades), intermediate for structure and species diversity (2.5 to 6 decades), and slowest for biomass and species composition (>12 decades). Network analysis shows three independent clusters of attribute recovery, related to structure, species diversity, and species composition. Secondary forests should be embraced as a low-cost, natural solution for ecosystem restoration, climate change mitigation, and biodiversity conservation.

Abstract Biodiversity studies rely heavily on estimates of species' distributions often obtained through ecological niche modelling. Numerous software packages exist that allow users to model ecological niches using machine learning and statistical methods. However, no existing package with a graphical user interface allows users to perform model calibration and selection based on convex forms such as ellipsoids, which may match fundamental ecological niche shapes better, incorporating tools for exploring, modelling, and evaluating niches and distributions that are intuitive for both novice and proficient users. Here we describe an r package, N iche T ool B ox ( ntbox ), that allows users to conduct all processing steps involved in ecological niche modelling: downloading and curating occurrence data, obtaining and transforming environmental data layers, selecting environmental variables, exploring relationships between geographic and environmental spaces, calibrating and selecting ellipsoid models, evaluating models using binomial and partial ROC tests, assessing extrapolation risk, and performing geographic information system operations via a graphical user interface. A summary of the entire workflow is produced for use as a stand‐alone algorithm or as part of research reports. The method is explained in detail and tested via modelling the threatened feline species Leopardus wiedii . Georeferenced occurrence data for this species are queried to display both point occurrences and the IUCN extent of occurrence polygon (IUCN, 2007). This information is used to illustrate tools available for accessing, processing and exploring biodiversity data (e.g. number of occurrences and chronology of collecting) and transforming environmental data (e.g. a summary PCA for 19 bioclimatic layers). Visualizations of three‐dimensional ecological niches modelled as minimum volume ellipsoids are developed with ancillary statistics. This niche model is then projected to geographic space, to represent a corresponding potential suitability map. Using ntbox allows a fast and straightforward means by which to retrieve and manipulate occurrence and environmental data, which can then be implemented in model calibration, projection and evaluation for assessing distributions of species in geographic space and their corresponding environmental combinations.

Correlational ecological niche models have seen intensive use and exploration as a means of estimating the limits of actual and potential geographic distributions of species, yet their application to explaining geographic abundance patterns has been debated. We developed a detailed test of this latter possibility based on the North American Breeding Bird Survey. Correlations between abundances and niche-centroid distances were mostly negative, as per expectations of niche theory and the abundant niche-centre relationship. The negative relationships were not distributed randomly among species: terrestrial, non-migratory, small-bodied, small-niche-breadth and restricted-range species had the strongest negative associations. Distances to niche centroids as estimated from correlational analyses of presence-only data thus offer a unique means by which to infer geographic abundance patterns, which otherwise are enormously difficult to characterise.

One-third of all Neotropical forests are secondary forests that regrow naturally after agricultural use through secondary succession. We need to understand better how and why succession varies across environmental gradients and broad geographic scales. Here, we analyze functional recovery using community data on seven plant characteristics (traits) of 1,016 forest plots from 30 chronosequence sites across the Neotropics. By analyzing communities in terms of their traits, we enhance understanding of the mechanisms of succession, assess ecosystem recovery, and use these insights to propose successful forest restoration strategies. Wet and dry forests diverged markedly for several traits that increase growth rate in wet forests but come at the expense of reduced drought tolerance, delay, or avoidance, which is important in seasonally dry forests. Dry and wet forests showed different successional pathways for several traits. In dry forests, species turnover is driven by drought tolerance traits that are important early in succession and in wet forests by shade tolerance traits that are important later in succession. In both forests, deciduous and compound-leaved trees decreased with forest age, probably because microclimatic conditions became less hot and dry. Our results suggest that climatic water availability drives functional recovery by influencing the start and trajectory of succession, resulting in a convergence of community trait values with forest age when vegetation cover builds up. Within plots, the range in functional trait values increased with age. Based on the observed successional trait changes, we indicate the consequences for carbon and nutrient cycling and propose an ecologically sound strategy to improve forest restoration success.

Recent published evidence indicates a negative correlation between density of populations and the distance of their environments to a suitably defined ‘niche centroid’. This empirical observation lacks theoretical grounds. We provide a theoretical underpinning for the empirical relationship between population density and position in niche space, and use this framework to understand the circumstances under which the relationship will fail. We propose a metapopulation model for the area of distribution, as a system of ordinary differential equations coupled with a dispersal kernel. We present an analytical approximation to the solution of the system as well as R code to solve the full model numerically. We use this tool to analyze various scenarios and assumptions. General and realistic demographic assumptions imply a good correlation between position in niche space and population abundance. Factors that modify this correlation are: transitory states, a heterogeneous spatial structure of suitability, and Allee effects. We also explain why the raw output of the niche modeling algorithm MaxEnt is not a good predictor of environmental suitability. Our results elucidate the empirical results for spatial patterns of population size in niche terms, and provide a theoretical basis for a structured theory of the niche.

Artificial intelligence (AI) has demonstrated its potential to transform numerous fields and education is no exception. In today’s digital age, AI has emerged as a powerful tool that is revolutionizing teaching and learning. In this article, we will explore the impact of artificial intelligence in education and how it is transforming the educational landscape at all levels. From personalizing learning to improving feedback and developing interactive resources, we will examine how AI is changing how we acquire knowledge and skills.

Abstract Environmental flows (e‐flows) are powerful tools for sustaining freshwater biodiversity and ecosystem services, but their widespread implementation faces numerous social, political, and economic barriers. These barriers are amplified in water‐limited systems where strong trade‐offs exist between human water needs and freshwater ecosystem protection. We synthesize the complex, multidisciplinary challenges that exist in these systems to help identify targeted solutions to accelerate the adoption and implementation of environmental flows initiatives. We present case studies from three water‐limited systems in North America and synthesize the major barriers to implementing environmental flows. We identify four common barriers: (a) lack of authority to implement e‐flows in water governance structures, (b) fragmented water governance in transboundary water systems, (c) declining water availability and increasing variability under climate change, and (d) lack of consideration of non‐biophysical factors. We then formulate actionable recommendations for decision makers facing these barriers when working towards implementing environmental flows: (a) modify or establish a water governance framework to recognize or allow e‐flows, (b) strive for collaboration across political jurisdictions and social, economic, and environmental sectors, and (c) manage adaptively for climate change in e‐flows planning and recommendations. This article is categorized under: Water and Life &gt; Conservation, Management, and Awareness Human Water &gt; Water Governance Engineering Water &gt; Planning Water

Freshwater biodiversity is under great threat across the globe as evidenced by more severe declines relative to other types of ecosystems. Some of the main stressors responsible for these concerning trends is habitat fragmentation, degradation, and loss stemming from anthropogenic activities, including energy production, urbanization, agriculture, and resource extraction. Habitat protection and restoration both play an integral role in efforts to save freshwater biodiversity and associated ecosystem services from further decline. In this paper, we summarize the sources of threats associated with habitat fragmentation, degradation, and loss and then outline response options to protect and restore freshwater habitats. Specific response options are to legislate the protection of healthy and productive freshwater ecosystems, prioritize habitats for protection and restoration, enact durable protections, conserve habitat in a coordinated and integrated manner, engage in evidence-based restoration using an adaptive management approach, ensure that potential freshwater habitat alterations are mitigated or off-set, and future-proof protection and restoration actions. Such work should be done through a lens that engages and involves local community members. We identify three broad categories of obstacles that could arise during the implementation of the response options outlined: (a) scientific (e.g., inaccessible data or uncertainties), (b) institutional and management (e.g., capacity issues or differing goals across agencies), and (c) social and political (e.g., prioritizing economic development over conservation initiatives). The protection and restoration of habitats is key to Bend the Curve for freshwater biodiversity, with a comprehensive, connected, and coordinated effort of response options needed to protect intact habitats and restore fragmented, degraded, and lost habitats and the biodiversity and ecosystem services that they support.

Sex in crocodilians is not determined by chromosomes, but by egg incubation temperature, where different temperatures produce different clutch sex ratios. Two patterns have been proposed to describe these changes in sex ratios: a 100% female proportion at low and high temperatures with male predominance at intermediate ones (FMF) or a simpler pattern with a single female-to-male transition (FM). Over the last three decades, researchers have provided empirical information to support either of these two patterns in different species; however, no consensus has been reached partly because data have not been analysed as a whole. Here, we aimed at gathering the existing data on these patterns to provide models of temperature-dependent sex determination in those crocodilians studied so far. Potentially relevant publications were searched on Web of Knowledge, Scopus, Scielo and Science Direct. Studies that reported results on the sexual identity of crocodilian hatchlings obtained from constant temperature incubation treatments were considered. Using statistical models varying in their underlying assumptions, we evaluated which sex-determination pattern was best supported for the studied crocodilians and constructed species-specific and latitude-specific models. Based on the 8,458 sexed hatchlings studied throughout 31 studies, we show that the evidence supports a shared FMF pattern in all the crocodilian species for which enough data are available. We find that such pattern changes between species and at different latitudes. These results suggest a lability of the FMF crocodilian sex-determination pattern, a key feature under the present climate change scenario.

Abstract The Neotropical otter Lontra longicaudis is a widespread semiaquatic carnivore living in a wide variety of environments in both fresh‐water and salt‐water ecosystems. We summarise the current knowledge on distribution, ecology, behaviour, evolution and conservation status of the species, and highlight the main threats that have been affecting it as well as priority actions for securing its survival. The current geographical range of Lontra longicaudis is discussed, as well as several efforts that have been made to update knowledge of the range. Throughout its known distribution area, the Neotropical otter has high genetic diversity, and recent molecular research suggests that variations in genetic diversity are related to geography. Taxonomic issues regarding the existence of subspecies persist, mainly due to limited sampling in key portions of the species’ range. Although the Neotropical otter is widely distributed in Latin America and has flexible behaviour, it is subjected to a variety of threats, which lead this otter to be officially considered Threatened in several countries within its geographical range. The species still faces an uncertain future due to the impact of human activities, thus justifying its classification as Near Threatened in the International Union for Conservation of Nature's Red List. The real level of human‐otter conflicts and the impact of modified environments on Neotropical otter populations are still unclear, and must be a priority focus of future studies. There is an urgent need to increase our knowledge on aspects of the Neotropical otter's biology, such as reproduction, generation time, behaviour, physiology, distribution limits, sanitary aspects, evolution and taxonomy. Understanding these topics is vital to ensure the long‐term survival of the species, both at the local and at the regional scale, as well as to provide the basis for environmental education actions involving local riverside human communities .

Land use change from forests to grazing lands is one of the important sources of greenhouse gas emissions in many parts of the tropics. The objective of this study was to analyze the extent of soil organic carbon (SOC) loss from the conversion of native forests to pasturelands in Mexico. We analyzed 66 sets of published research data with simultaneous measurements of soil organic carbon stocks between native forests and pasturelands in Mexico. We used a generalized linear mixed effect model to evaluate the effect of land use change (forest versus pasture), soil depth, and original native forest types. The model showed that there was a significant reduction in SOC stocks due to the conversion of native forests to pasturelands. The median loss of SOC ranged from 31.6% to 52.0% depending upon the soil depth. The highest loss was observed in tropical mangrove forests followed by highland tropical forests and humid tropical forests. Higher loss was detected in upper soil horizon (0–30 cm) compared to deeper horizons. The emissions of CO2 from SOC loss ranged from 46.7 to 165.5 Mg CO2 eq. ha−1 depending upon the type of original native forests. In this paper, we also discuss the effect that agroforestry practices such as silvopastoral arrangements and other management practices like rotational grazing, soil erosion control, and soil nutrient management can have in enhancing SOC stocks in tropical grasslands. The results on the degree of carbon loss can have strong implications in adopting appropriate management decisions that recover or retain carbon stocks in biomass and soils of tropical livestock production systems.

Neotropical Dry Forests are important biodiversity hotspots characterized by intermediate to high levels of species richness and endemism. A possible explanation for these characteristics is that such forests have been less affected by drastic glacial impacts than other biomes. Using two approaches, geo-statistical phylogeography, based on two chloroplast markers, and multi-algorithm-based niche modelling, for the present and for the past, we explored if, during glacial periods, the geographical range of Bulnesia sarmientoi was stable or underwent expansions or retractions in space and time and if there is a relationship among past climatic refugia, the current climatic optimum and genetic diversity. We estimated that B. sarmientoi would have diverged from other Bulnesia at the beginning of the Pliocene (5 Mya), with diversification of the current lineages occurring in the Pleistocene (1.4-1.1 Mya). Our results suggest that Dry Forests underwent population expansion events during the glacial periods, whereas they would have undergone population stasis during interglacial periods. Furthermore, we identified a putative refugial area in the Dry Chaco that has been climatically stable through time, consistent with the area of highest genetic diversity and with the spatial location of the climatic optimum of the focal species.

Abstract Silvopastoral systems have great potential for storing carbon because of carbon assimilation in tree woody biomass, carbon input through litterfall and below‐ground carbon turnover. In this study, we quantified and compared the carbon stocks at livestock ranches in Tabasco, Mexico, containing either scattered trees in grazing pastures (STP) or grass monocultures. Sampling plots were randomly established at each ranch where the above‐ and below‐ground carbon stocks, carbon input from litterfall, grass production and arboreal biomass growth were measured. We found that silvopastoral systems stored an average of 257.45 Mg ha −1 of soil organic carbon (SOC) compared to 119.17 Mg SOC ha −1 at grass monoculture ranches (to 30 cm depth); silvopastoral systems also stored 44.64 Mg C ha −1 in wood biomass; and, grass monocultures had greater cumulative grass biomass production. Overall, it is concluded that livestock ranches in Tabasco, Mexico, with scattered trees in grazing pastures stored 58.8% more carbon than those grass monocultures, with carbon stocks of 327.01 Mg C ha −1 and 134.47 Mg C ha −1 , respectively. The results are useful for land management decision making for sustainable livestock systems framed in the Sustainable Development Goals (SDGs).

Bat acoustic libraries are important tools that assemble echolocation calls to allow the comparison and discrimination to confirm species identifications. The Sonozotz project represents the first nation-wide library of bat echolocation calls for a megadiverse country. It was assembled following a standardized recording protocol that aimed to cover different recording habitats, recording techniques, and call variation inherent to individuals. The Sonozotz project included 69 species of echolocating bats, a high species richness that represents 50% of bat species found in the country. We include recommendations on how the database can be used and how the sampling methods can be potentially replicated in countries with similar environmental and geographic conditions. To our knowledge, this represents the most exhaustive effort to date to document and compile the diversity of bat echolocation calls for a megadiverse country. This database will be useful to address a range of ecological questions including the effects of anthropogenic activities on bat communities through the analysis of bat sound.

Understanding the climatic and historical factors shaping species richness is a major goal of ecology and biogeography. Consensus on how climate affects species richness is still lacking, but four potential and non-exclusive explanations have emerged: water-energy, where diversity is determined by precipitation and/or temperature; seasonality, where diversity is determined by seasonal variation in climate; heterogeneity, where diversity is determined by spatial variability in climate; and historical climatic stability, where diversity is determined by changes in climate through evolutionary time. Climate–richness relationships are also mediated by historical processes such as phylogenetic niche conservatism and lineage diversification across regions. We evaluated the effect of climate on species richness gradients of Anolis lizards and tested the role of phylogenetic niche conservatism (PNC) and regional diversification (RD) in the origin and maintenance of climate-richness relationships. Climate had a strong non-stationary relationship with species richness with strong shared effects among several climate axes. Regional differences in climate–richness relationships suggest different assembly processes between regions. However, we did not find evidence for a role of evolutionary factors such as PNC or RD underlying these relationships. We suggest that evolutionary processes affecting climate-richness relationships in Anolis likely were obscured by high dispersal rates between regions.

For much of the twentieth century, many or most scholarly journals in biodiversity, ecology, biogeography and conservation were owned and published by scientific societies and made available to the broader scientific community at relatively low cost. However, the past several decades have seen a dominant process of commercialization of the publication process in this field, either by commercial publishing firms taking over publication of journals owned by a society (e.g., Evolution), or by commercial publishers starting new journals to fill “niches” that were until then empty in the scholarly publishing ecosystem. Diversity and Distributions is an example of this latter category of journals, having been created by Wiley Publishers in 1993 (as Biodiversity Letters). Being a journal owned by a commercial publisher, it has always been accessed by readers via subscription, but the publication process has been free to potential authors whose work has passed peer review. We are pleased to announce that Diversity and Distributions will join the Wiley Open Access portfolio as of 1st January 2019, when all articles (including the entire back catalogue) will become free to read, download and share for all. This exciting development will place the journal at the forefront of open science in the community. This change would appear to be positive, as it would remove the for-pay subscription barrier to reader access to the journal, and thus would appear to constitute an intriguing step in a series of advances in opening access to the scientific literature, in line with recent proposals as those of cOAlition S (https://www.scienceeurope.org/coalition-s/). However, the good news on the webpage is followed by a more ominous, “... all submissions received after 8th October 2018 will be subject to an Article Processing Charge (APC).” We have come to understand that these APCs will be US$2,200 per paper published, which is very expensive compared with the bulk of open access journals in the fields of ecology and conservation science (Van Noorden, 2013; Solomon & Björk, 2012a, 2012b). As authors (generators), reviewers and editors (evaluators), and readers (consumers) of papers published in this field, we write this commentary to express our strongest disagreement with the planned shift to APC-based open access for Diversity and Distributions. Whatever the business model, Diversity and Distributions has become a lead journal in the field thanks to the free-of-charge support of the scientific community as editors and reviewers and has long been a zero-cost publishing outlet. Of course, it has not been an easily accessible journal for the readers, as it has been behind a paywall (i.e., pay-for-view), but the work has indeed been published, and readers have accessed papers via author request, institutional subscriptions, Sci-Hub (Himmelstein et al., 2018), institutional repositories, preprint archives that conform to copyright restrictions, or other platforms. Wiley's “open access” solution changes the equation radically, making the journal accessible to readers, but effectively off-limits to many potential authors. The community of scholars in biodiversity, ecology, biogeography, and conservation has become and is continuing to be increasingly diverse and global, distributed across borders of countries, levels of economic potential, and institutional size. As a consequence, the community varies dramatically in its economic ability, for example, to pay US$2,200 to publish a paper. The Diversity and Distributions page states, “... automatic APC waivers and discounts will be given to authors from countries on the Waivers and Discounts List,” yet the list is quite short, including automatic waivers to only 69 countries worldwide and discounts to only 49 countries that have contributed few papers to Diversity and Distributions (7 with waivers and 7 with discounts in 2017, according to information provided by Wiley), and excluding countries with scarce economic resources for science such as Cuba and Venezuela. In addition to scientists in countries for which the discounts are not sufficient, researchers in many countries not on that list will also not be able to pay, with the planned APC exceeding a senior investigator's yearly income in some cases. In truth, authors at smaller institutions or working without grants at larger institutions even in the United States, Canada, Australia and Europe, will often find it difficult to come up with this sum. In response to initial protests, particularly from a large number of the Associate Editors of the journal, Wiley agreed to a broader waiver policy: “Ability to pay the APC should not be a barrier to the publication of important science. Authors without funding for publication charges will be provided with a waiver of the APC.” Although Wiley Publishers plans to offer waivers, we note that a substantial body of literature documents the fact that such fee-waiver requests carry a stigma, and frequently constitute a significant barrier to participation in a wide variety of activities (Berk & Moon, 2016; Challed, 1996). Also, Wiley Publishers has not made clear whether they will include university funds in the “ability to pay,” or what sort of documentation will be required to document authors’ inability to pay. Quite simply, given the global nature of the challenges of biodiversity conservation, excluding voices—and particularly voices from countries that frequently are those holding the richest biodiversity—does not seem to be a beneficial or equitable path to take, and we do not wish to see Diversity and Distributions make such a change. We think that this problem arises from an inappropriate choice of business model for scientific journals and for lack of consultation with the client community. Surely, Wiley Publishers is well aware of the increasing number of journal subscription cancellations by large research institutions (SPARC, 2018) and is presumably exploring and developing new future revenue streams for its massively profitable enterprise. That is to say, the traditional subscription model may be approaching the end of its profitability (Else, 2018); for publishers and scientists alike, another model is needed, and an open access model sounds good politically. However, any such change should be made considering the consequences for the community in question, and for the journal itself. Clearly, the Diversity and Distributions decision was not taken out of a deep, carefully considered concern for open participation in scholarly publishing, which would have taken into account the effects of high APC rates on full participation by the journal's constituency. The authors of this commentary are a large group of scientists based at institutions around the world, including 40 of the associate editors of Diversity and Distributions at the time of writing. All of us view Diversity and Distributions as an important element in our community's scholarly communications universe. The shift to an “author pays” publishing model damages the essential role of the journal deeply, as it will make publishing there expensive and potentially off-limits for us and many of our colleagues. Collectively, we have published numerous papers in Diversity and Distributions and have donated many hundreds of hours reviewing and editing papers for the journal as well, to the massive financial benefit of Wiley Publishers. We note that Wiley Publishers saw a net profit of $252,000,000 in 2017 (Matthews, 2018), which is enough net profit to cover the APCs for 114,545 articles costing $2,200! Hence, presumably, substantial room exists to reduce profit margins and increase participation for a journal in a field like that of Diversity and Distributions. We therefore tentatively applaud Wiley Publishers’ reconsideration of its initial author-pays plans for the journal Diversity and Distributions, and their offer of strong, equitable waivers and discounts. If Wiley Publishers indeed holds to its promise not to let APCs be a barrier to scholarly communication, we would see the new situation more positively; even better would be a “platinum” open access business model, in which external subsidy is used to avoid crippling APCs. Some platinum open access journals have close relationships with scientific societies or charitable foundations, are subsidized by a particular institution or entity, or charge much more modest APCs in exchange for membership dues; examples of journals using these different funding solutions include Perspectives in Ecology and Conservation, Current Science, Current Zoology, Emerging Infectious Diseases, European Journal of Ecology, Neotropical Biodiversity, and Revista Mexicana de Biodiversidad. If, however, Wiley Publishers does not hold to its “no APC barriers” policy (e.g., if they start withholding waivers to authors claiming lack of funds), we anticipate that Diversity and Distributions will see a rather rapid decline in submission rates of quality papers, out of both economic necessity and “protest” by the community. As members of the research community, we would likely send our manuscripts for publication elsewhere and reconsider our customary volunteer work as referees and editors for such a high-cost and low-participation journal. More generally, we urge that Wiley Publishers and other commercial publishers realize that the future of scholarly publishing is not just one of open access, but rather open participation, such that the fullest scholarly community can participate in all dimensions of scholarly communications.

We assess a body of work that has attempted to use co-occurrence networks to infer the existence and type of biotic interactions between species. Although we see considerable interest in the approach as an exploratory tool for understanding patterns of co-occurrence of species, we note and describe numerous problems in the step of inferring biotic interactions from the co-occurrence patterns. These problems are both theoretical and empirical in nature, and limit confidence in inferences about interactions rather severely. We examine a series of examples that demonstrates striking discords between interactions inferred from co-occurrence patterns and previous experimental results and known life-history details.

Antecedentes y Objetivos: Se presenta el primer listado florístico de las playas y dunas costeras de México, actualizado y respaldado por ejemplares de herbario.Métodos: Se revisaron 14 herbarios nacionales y extranjeros. Se sobrepuso una retícula de 2 × 2 km al mapa de la costa y de las dunas costeras de México para referir todos los registros que corresponden a 2180 sitios con 12,419 ejemplares de plantas. Se calcularon índices de diversidad, similitud, diversidad taxonómica y redundancia.Resultados clave: La flora registrada consta de 153 familias, 897 géneros y 2075 especies de plantas vasculares, las cuales representan 9.5% de la flora vascular de México. Las cinco colecciones con índices de redundancia altos IR≥0.7 son los herbarios de la Universidad Nacional Autónoma de México (MEXU, IR=0.9), del Centro de Investigación Científicas de Yucatán (CICY, IR=0.8), y los del Centro de Investigaciones Biológicas del Noroeste (HCIB), el Instituto de Ecología, A.C. (XAL) y el del Museo de Historia Natural de San Diego (SD), cada uno con un IR de 0.7. Se reconocen cinco regiones florísticas que corresponden a los mares de México. El Pacífico Norte tiene mayor diversidad taxonómica y el Pacífico Sur menor diversidad taxonómica. El Golfo de California, Golfo de México y Mar Caribe tienen diversidades taxonómicas similares. Las especies con más registros son Trianthema portulacastrum (165), Croton punctatus (107), Echites umbelllatus (106) e Ipomoea pes-caprae (90). Por el carácter de ecotono de las dunas costeras, la mayoría de las especies se comparten con los tipos de vegetación vecinos (selvas, matorrales, y humedales como las marismas y manglares).Conclusiones: Esta primera lista de la flora en playas y dunas de México es la base para múltiples estudios florísticos regionales y locales, biogeográficos, y ecológicos; además, que será importante para su uso en temas de impacto ambiental y manejo costero.

The loss and degradation of forests in tropical regions have modified tree cover, creating deforested landscapes. It has been suggested that there are thresholds in these landscapes beyond which the diversity, distribution, abundance, and fitness of different biological groups can be affected. In this study, the ecological habitat thresholds were detected for eight populations of phyllostomid bats along an environmental gradient of forest loss in the Huasteca region, Mexico. At a local scale, we analyzed canopy loss, and we also detected these thresholds at the landscape level, as a function of forest remnant area at three scales with radii of 1, 3 and 5 km. The data were analyzed using the Threshold Indicator Taxa ANalysis (TITAN) method for detecting indicator species along gradients. The bats exhibited three different types of response to habitat loss: 1) Leptonycteris yerbabuenae, Chiroderma salvini, Sturnira hondurensis, and Artibeus lituratus were more abundant where canopy cover was present at the local site, even though the landscape had been deforested; 2) Sturnira parvidens and Artibeus jamaicensis required tree cover at all spatial scales; and 3) Glossophaga soricina and Desmodus rotundus are species that might be locally abundant in habitats with little canopy, but both species need landscapes that have not been deforested. In conclusion, these populations of phyllostomid bats were sensitive to deforestation in different ways, their response to the habitat loss gradient varying among species and with spatial scale.