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4,274 result(s) for "ecoregions"
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Climate drives shifts in grass reproductive phenology across the western USA
The capacity of grass species to alter their reproductive timing across space and through time can indicate their ability to cope with environmental variability and help predict their future performance under climate change. We determined the long-term (1895–2013) relationship between flowering times of grass species and climate in space and time using herbarium records across ecoregions of the western USA. There was widespread concordance of C3 grasses accelerating flowering time and general delays for C4 grasses with increasing mean annual temperature, with the largest changes for annuals and individuals occurring in more northerly, wetter ecoregions. Flowering time was delayed for most grass species with increasing mean annual precipitation across space, while phenology–precipitation relationships through time were more mixed. Our results suggest that the phenology of most grass species has the capacity to respond to increases in temperature and altered precipitation expected with climate change, but weak relationships for some species in time suggest that climate tracking via migration or adaptation may be required. Divergence in phenological responses among grass functional types, species, and ecoregions suggests that climate change will have unequal effects across the western USA.
Global trade-offs of functional redundancy and functional dispersion for birds and mammals
Aim The diversity of birds and mammals is typically described in separate analyses, but species may play similar roles. Here, we develop a comparative trait framework for birds and mammals to provide a global quantification of the similarity of species roles (functional redundancy) and the breadth of roles across taxa (functional dispersion). We predict different contributions of birds and mammals to redundancy and dispersion, and unique geographical patterns of redundancy and dispersion by including both taxa. Location Global. Time period Contemporary. Major taxa studied Birds and mammals. Methods We systematically select, compile and impute the same six traits (i.e., a common currency of traits) across 15,485 bird and mammal species from multiple databases. We use these six traits to compute functional redundancy and functional dispersion for birds and mammals across all 825 terrestrial ecoregions. We then calculate the standardized effect size (SES) of these observed values compared with null expectations, based on a randomization of species composition (i.e., independent of differences in species richness). Results We find that species‐rich regions, such as the Neotropics, have high functional redundancy coupled with low functional dispersion, characterizing a global trade‐off. Thus, in general, as species richness increases, the similarity in species functional roles also increases. We therefore suggest that different processes generate species richness/functional redundancy and functional dispersion, leading to a novel, and generally non‐tropical, distribution of hotspots of high functional dispersion across Madagascar, Eastern Asia and Western USA. Main conclusions We recommend consideration of both the similarity and the breadth of functional roles across species pools, including taxa that may play similar roles. We therefore suggest that functional redundancy, as a means of insurance, and functional dispersion, as an indicator of response diversity, should be evaluated further as conservation objectives.
An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm
We assess progress toward the protection of 50% of the terrestrial biosphere to address the species-extinction crisis and conserve a global ecological heritage for future generations. Using a map of Earth’s 846 terrestrial ecoregions, we show that 98 ecoregions (12%) exceed Half Protected; 313 ecoregions (37%) fall short of Half Protected but have sufficient unaltered habitat remaining to reach the target; and 207 ecoregions (24%) are in peril, where an average of only 4% of natural habitat remains. We propose a Global Deal for Nature—a companion to the Paris Climate Deal—to promote increased habitat protection and restoration, national- and ecoregion-scale conservation strategies, and the empowerment of indigenous peoples to protect their sovereign lands. The goal of such an accord would be to protect half the terrestrial 2050 to halt the extinction crisis while sustaining human livelihoods.
Updated distribution map and notes on the cranial morphometry of Dasyprocta azarae Lichtenstein, 1823, Azara rsquo;s Agouti (Mammalia, Rodentia, Dasyproctidae), in South America
Dasyprocta azarae Lichtenstein, 1823 is currently distributed in Argentina, Brazil, and Paraguay, with controversial records in Bolivia. Recent records using trail cameras have expanded its distribution in the Chaco region of Paraguay, but its distribution remains unclear because of its morphological similarity to species in Bolivia and northwestern Argentina. We present an updated map of distribution of D. azarae based on the review of specimens in biological collections and literature. Our results show that D. azarae is distributed in four biomes, across 11 ecoregions, and has an extent of occurrence of 2,512,985 km2.
Generalized provisional seed zones for native plants
Deploying well-adapted and ecologically appropriate plant materials is a core component of successful restoration projects. We have developed generalized provisional seed zones that can be applied to any plant species in the United States to help guide seed movement. These seed zones are based on the intersection of high-resolution climatic data for winter minimum temperature and aridity (as measured by annual heat : moisture index), each classified into discrete bands. This results in the delineation of 64 provisional seed zones for the continental United States. These zones represent areas of relative climatic similarity, and movement of seed within these zones should help to minimize maladaptation. Superimposing Omernik's level III ecoregions over these seed zones distinguishes areas that are similar climatically yet different ecologically. A quantitative comparison of provisional seed zones with level III ecoregions and provisional seed zones within ecoregions for three species showed that provisional seed zone within ecoregion often explained the greatest proportion of variation in a suite of traits potentially related to plant fitness. These provisional seed zones can be considered a starting point for guidelines for seed transfer, and should be utilized in conjunction with appropriate species-specific information as well as local knowledge of microsite differences.
Color, chlorophyll a, and suspended solids effects on Secchi depth in lakes
Secchi depth (SD), a primary metric to assess trophic state, is controlled in many lakes by algal densities, measured as chlorophyll-a (chl-a) concentration. Two other optically related water quality variables also directly affect SD: non-algal suspended solids (SSNA) and colored dissolved organic matter (CDOM, expressed as the absorption coefficient at 440 nm, a 440). Using a database of ~1,460 samples from ~625 inland lake basins in Minnesota and two other Upper Midwest states, Wisconsin and Michigan, we analyzed relationships among these variables, with special focus on CDOM levels that influence SD values and the Minnesota SD standards used to assess eutrophication impairment of lakes. Log-transformed chl-a, total suspended solids (TSS), and SD were strongly correlated with each other; log(a 440) had major effects on log(SD) but was only weakly correlated with log(chl-a) and log(TSS). Multiple regression models for log(SD) and 1/SD based on the three driving variables (chl-a, SSNA, and CDOM) explained ~80% of the variance in SD in the whole data set, but substantial differences in the form of the best-fit relationships were found between major ecoregions. High chl-a concentrations (< 50 μg/L) and TSS (< 20 mg/L) rarely occurred in lakes with high CDOM (a 440 > ~4 m−1), and all lakes with a 440 > 8 m−1 had SD ≤ 2.0 m despite low chl-a values (<10 μg/L) in most lakes. Further statistical analyses revealed that CDOM has significant effects on SD at a 440 values > ~4 m−1. Thus, SD is not an accurate trophic state metric in moderately to highly colored lakes, and Minnesota’s 2-m SD criterion should not be the sole metric to assess eutrophication impairment in warm/cool-water lakes of the Northern Lakes and Forest ecoregion. More generally, trophic state assessments using SD in regions with large landscape sources of CDOM need to account for effects of CDOM on SD.
Global biogeography of estuary-associated fishes
This study examines global zoogeographic patterns of estuary-associated fishes using meta-assemblages compiled at the marine ecoregion scale. The classification of biogeographic regions based on estuary-associated fish species is assessed in relation to marine and freshwater zoogeographic patterns. Historical (palaeobiogeographic) and contemporary environmental factors that contribute to the establishment and maintenance of these regions are also discussed. Global patterns in estuary-associated fish species richness demonstrated that tropical ecoregions are more diverse and richer in species than temperate ecoregions; the tropical Indo-Pacific and the tropical western Atlantic were two major centres of high global species richness. Multivariate analyses identified several ecoregion groupings that broadly corresponded with both freshwater and marine biogeographic regions. These groupings could also be related to global marine palaeobiogeographic processes such as the closure of the Tethys Sea linkage during the Cenozoic as well as contemporary factors such ocean currents, upwelling areas and climatic factors, particularly rainfall and runoff.
Distribution mapping of world grassland types
AIM: National and international policy frameworks, such as the European Union's Renewable Energy Directive, increasingly seek to conserve and reference ‘highly biodiverse grasslands’. However, to date there is no systematic global characterization and distribution map for grassland types. To address this gap, we first propose a systematic definition of grassland. We then integrate International Vegetation Classification (IVC) grassland types with the map of Terrestrial Ecoregions of the World (TEOW). LOCATION: Global. METHODS: We developed a broad definition of grassland as a distinct biotic and ecological unit, noting its similarity to savanna and distinguishing it from woodland and wetland. A grassland is defined as a non‐wetland type with at least 10% vegetation cover, dominated or co‐dominated by graminoid and forb growth forms, and where the trees form a single‐layer canopy with either less than 10% cover and 5 m height (temperate) or less than 40% cover and 8 m height (tropical). We used the IVC division level to classify grasslands into major regional types. We developed an ecologically meaningful spatial catalogue of IVC grassland types by listing IVC grassland formations and divisions where grassland currently occupies, or historically occupied, at least 10% of an ecoregion in the TEOW framework. RESULTS: We created a global biogeographical characterization of the Earth's grassland types, describing approximately 75% of IVC grassland divisions with ecoregions. We mapped 49 IVC grassland divisions. Sixteen additional IVC grassland divisions are absent from the map because of the fine‐scale distribution of these grassland types. MAIN CONCLUSIONS: The framework provided by our geographical mapping effort provides a systematic overview of grasslands and sets the stage for more detailed classification and mapping at finer scales. Each regional grassland type can be characterized in terms of its range of biodiversity, thereby assisting in future policy initiatives.
DIVERSITY AND DISTRIBUTION OF LICHEN TAXA IN ARGENTINA
Lichens are symbiotic associations where a fungus forms a partnership with one or more photosynthetic organisms, like algae or cyanobacteria. They are capable of thriving in a wide range of environments, from desert regions to tropical forests, aquatic ecosystems to mountainous areas, and can grow on rocks, trunks, leaves, soil, and anthropogenic substrates. The aim of this study is to determine the lichen richens in Argentina and their diversity across each province. This study provides an updated assessment of lichen diversity and distribution in Argentina, documenting 1,864 taxa (species and infraspecific taxa), representing a 16% increase since the last catalog. Southern regions (Tierra del Fuego, Islas del Atlántico Sur, Río Negro) showed the highest richness, while northern and central-western region exhibited lower diversity, partly due to historical sampling biases. Three indices (taxonomic biodiversity, ecoregion-based diversity, and aridity-adjusted diversity) revealed that lichen distribution is shaped by climate, substrate availability, and uneven research effort rather than strict latitudinal gradients. The findings underscore the need for targeted fieldwork in underrepresented regions (arid northwest), molecular taxonomic revisions, and collaborative efforts to address knowledge gaps. Los líquenes son asociaciones simbióticas en las que un hongo interactúa con uno o más organismos fotosintéticos, como algas o cianobacterias. Ellos son capaces de prosperar en una amplia gama de ambientes, desde regiones desérticas hasta bosques tropicales, ecosistemas acuáticos hasta áreas montañosas, y pueden crecer en rocas, troncos, hojas, suelo y sustratos antropogénicos. El objetivo es determinar la riqueza de líquenes en Argentina y la diversidad en cada provincia. Este estudio proporciona una evaluación actualizada de la diversidad y distribución de líquenes en Argentina, documentando 1.867 taxones (especies y categorías infraespecíficas), lo que representa un aumento del 16% desde el último catálogo. Las regiones del sur (Tierra del Fuego, Islas del Atlántico Sur, Río Negro) mostraron la mayor riqueza, mientras que las provincias del norte y centro-oeste exhibieron una diversidad menor, en parte debido a sesgos de muestreo históricos. Tres índices (biodiversidad taxonómica, diversidad basada en ecorregiones y diversidad ajustada a la aridez) revelaron que la distribución de líquenes está determinada por el clima, la disponibilidad de sustrato y el esfuerzo de investigación desigual en lugar de gradientes latitudinales estrictos. Los hallazgos subrayan la necesidad de realizar trabajos de campo específicos en regiones subrepresentadas (noroeste árido), revisiones taxonómicas moleculares y esfuerzos de colaboración para abordar las lagunas de conocimiento.
Description of a new subgenus for Himalaea batanga and its new sister species from Xizang Autonomous Region, China (Lepidoptera, Noctuidae, Amphipyrinae, Psaphidini)
A new subgenus, Macrohimalaea subgen. nov. , in the genus Himalaea Hreblay & L. Ronkay, 1998, is established and described for Himalaea (Macrohimalaea) batanga Saldaitis, Benedek & Volynkin, 2022 and for a new species, Himalaea (Macrohimalaea) silvana sp. nov. This new species is the type of the new subgenus. The new subgenus is distinct from the nominotypical one in having antennal pectination and its forewing shape and male genitalia. All four known adult specimens of the genus and their genitalia are illustrated and compared. Their collection localities are mapped.