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Soberon, J.

Publications and source records attributed to Soberon, J..

6 recordsLinked to original sources

Pollinators in Mexico. Spatial patterns show exceptions to global trends

Pollinators are declining globally, yet their biodiversity patterns in megadiverse regions remain unclear. We analyzed four major pollinator groups across one of the worlds most diverse regions -Mexico and adjacent areas. Using species distribution models, we generated presence- absence matrices (1,135 species in 165,078 grid cells) and applied range-diversity plots with a new randomization approach, to explore richness and endemism. Results reveal sharp contrasts: hummingbirds, bats, hawkmoths, and some bee families show the expected tropical richness peak, whereas other bees peak in arid lands of northern Mexico and the southwestern US. Endemism also diverges, with vertebrates concentrated in the tropics and bees in deserts. These findings challenge assumptions of uniform pollinator diversity patterns and demonstrate that conservation cannot rely on one-size-fits-all solutions. Our framework offers spatial tools to identify biodiversity structure and inform conservation and policy in the face of land-use change, agrochemicals, invasive species, and climate pressures.

ecology↗

Land-cover change in Cuba may favor biodiversity: An example using Omphalea (Angiosperma: Euphorbiaceae) and Urania boisduvalii (Lepidoptera: Uraniidae)

Changes in land cover directly affect biodiversity. Here we assessed land-cover change in Cuba in the past 35 years and analyzed how this change may affect the distribution of Omphalea plants and Urania boisduvalii moths. We analyzed the vegetation cover of the Cuban archipelago between 1985 and 2020. We used Google Earth Engine to classify two satellite image compositions into seven cover types: forest and shrubs, mangrove, soil without vegetation cover, wetlands, pine forest, agriculture, and water bodies. We considered three different areas for quantifications of land-cover change: (1) protected areas, (2) areas of potential distribution of Omphalea, and (3) areas of potential distribution of the plant within the protected areas. We found that the category of "forest and shrubs" have increased significantly in Cuba in the past 35 years and that most of the gained forest and shrub areas were agricultural land in the past. This same pattern was observed in the areas of potential distribution of Omphalea; whereas almost all cover types were mostly stables inside the protected areas. The transformation of agricultural areas into forest and shrubs could represent an interesting opportunity for biodiversity conservation in Cuba. Other detailed studies about biodiversity composition in areas of forest and shrubs gain would greatly benefit our understanding on the value of such areas for conservation.

ecology↗

Estimating the fundamental niche: accounting for the uneven1availability of existing climates

Studies that question important conceptual and methodological aspects of the field of ecological niche modeling (and species distribution modeling) have cast doubts on whether it is possible to estimate the fundamental niche of a species using presence-only data. The main limitation in niche estimation is that presence data come from the realized niche, which is only a subset of the fundamental niche. Most of the existing methods lack the ability to overcome this limitation and therefore fit niches that resemble the realized niche. To obtain a more accurate estimate of the fundamental niche, we propose using the geographic region that is accessible to a species (based on its dispersal ability) to determine a sampling distribution, in environmental space, from which we can quantify the likelihood of observing a particular environmental combination in a sample of presence points. We incorporate this sampling distribution into a multivariate normal model (i.e., a Mahalanobis distance model) by creating a weight function that modifies the probabilities of observing different environmental combinations in a sample of presences. This modification accounts for the uneven availability of environmental conditions. We show that the parameters of this weighted-normal model can be approximated with a maximum likelihood estimation approach; and then used to draw ellipsoids (confidence regions) that represent the fundamental niche of the species. We illustrate the application of our model with two worked examples. First, we use presence data for an invasive species and an accessible area that includes only its native range to evaluate whether the fitted model predicts confirmed establishments of the species outside its native range. Second, we use presence data for closely related species with known accessible areas to demonstrate how the different dispersal abilities of the species constrain a classic Mahalanobis distance model. Overall, we show that accounting for the distribution of environmental conditions that are accessible to a species indeed affects the estimation of the ellipsoids used to model its fundamental niche.

ecology↗

Geographic potential of the world largest hornet, Vespa mandarinia Smith (Hymenoptera: Vespidae), worldwide and particularly in North America

The Asian giant hornet (AGH, Vespa mandarinia) is the worlds largest hornet, occurring naturally in the Indomalayan region, where it is a voracious predator of pollinating insects including honey bees. In September 2019, a nest of Asian giant hornets was detected outside of Vancouver, British Columbia and in May 2020 an individual was detected nearby in Washington state, indicating that the AGH successfully overwintered in North America. Because hornets tend to spread rapidly and become pests, reliable estimates of the potential invasive range of V. mandarinia in North America are needed to assess likely human and economic impacts, and to guide future eradication attempts. Here, we assess climatic suitability for AGH in North America, and suggest that, without control, this species could establish populations across the Pacific Northwest and much of eastern North America. Predicted suitable areas for AGH in North America overlap broadly with areas where honey production is highest, as well as with species-rich areas for native bumble bees and stingless bees of the genus Melipona in Mexico, highlighting the economic and environmental necessity of controlling this nascent invasion.

ecology↗

On Some Problems of Estimating Fundamental Niche from Physiological Data

Hutchinson proposed the idea of the fundamental niche, determined by physiological properties of a species, more than 50 years ago. The idea remains both central to ecological thinking and largely unexplored experimentally. In this note, we describe some problems of using physiological experiments databases to estimate fundamental niches, show some solutions, and the apply our solution to testing the prediction that fundamental niches contain realized niches, for some species of marine fishes and terrestrial beetles. Our results were concordant with Hutchinsons predictions.

ecology↗