Walter Jacob Eyerdam

Background: The genus Pinguicula harbors 110 species, of which 53 are distributed in Mexico. The formation of the Mexican mountains has favored the Pinguicula diversification. Pinguicula specimens collected in the State of México, along the Trans-Mexican Volcanic Belt (TMVB) do not correspond with any known species. Questions: Do the collected specimens belong to a new species? What is its conservation status? How many Pinguicula species are there along the TMVB and how do they differentiate? How is the Pinguicula species richness distributed? Studied species: Pinguicula. Study site and dates: TMVB, 2005-2023. Methods: Based on herbarium specimens and recently collected material, a morphological analysis and description were made. Conservation status was assessed following IUCN Red List Categories and Criteria. Herbarium specimens and digital records of Pinguicula from the TMVB were examined to generate a list and key. We analyzed the richness distribution of Pinguicula by states, vegetation types, elevation ranges, and grid cells. Results: Pinguicula tlahuica is proposed as a new species. It is distinguished by the linear-spatulate summer leaves. The new species falls into the Endangered (EN) category. Along the TMVB, 16 species of Pinguicula are distributed. The State of México, Hidalgo and Michoacán, and the pine-oak forest were the richest. Pinguicula appeared between 759-3,427 m asl. The grid cell analyses revealed different areas with high richness. Conclusions: Along the TMVB, the Pinguicula species richness centered on the Eastern and Western sectors. Pinguicula crassifolia, P. michoacana, P. tlahuica, and P. zamudioana are endemic to the TMVB.

Species are often expected to shift their distributions either poleward or upslope to evade warming climates and colonise new suitable climatic niches. However, from 18‐years of fixed transect monitoring data on 88 species of butterfly in the midwestern United States, we show that butterflies are shifting their centroids in all directions, except towards regions that are warming the fastest (southeast).Butterflies shifted their centroids at a mean rate of 4.87 km year−1. The rate of centroid shift was significantly associated with local climate change velocity (temperature by precipitation interaction), but not with mean climate change velocity throughout the species' ranges.Species tended to shift their centroids at a faster rate towards regions that are warming at slower velocities but increasing in precipitation velocity.Surprisingly, species' thermal niche breadth (range of climates butterflies experience throughout their distribution) and wingspan (often used as metric for dispersal capability) were not correlated with the rate at which species shifted their ranges.We observed high phylogenetic signal in the direction species shifted their centroids. However, we found no phylogenetic signal in the rate species shifted their centroids, suggesting less conserved processes determine the rate of range shift than the direction species shift their ranges.This research shows important signatures of multidirectional range shifts (latitudinal and longitudinal) and uniquely shows that local climate change velocities are more important in driving range shifts than the mean climate change velocity throughout a species' entire range.

Biological invasions are among the threats to global biodiversity and social sustainability, especially on islands. Identifying the threshold of area at which non-native species begin to increase abruptly is crucial for early prevention strategies. The small-island effect (SIE) was proposed to quantify the nonlinear relationship between native species richness and area but has not yet been applied to non-native species and thus to predict the key breakpoints at which established non-native species start to increase rapidly. Based on an extensive global dataset, including 769 species of non-native birds, mammals, amphibians and reptiles established on 4277 islands across 54 archipelagos, we detected a high prevalence of SIEs across 66.7% of archipelagos. Approximately 50% of islands have reached the threshold area and thus may be undergoing a rapid increase in biological invasions. SIEs were more likely to occur in those archipelagos with more non-native species introduction events, more established historical non-native species, lower habitat diversity and larger archipelago area range. Our findings may have important implications not only for targeted surveillance of biological invasions on global islands but also for predicting the responses of both non-native and native species to ongoing habitat fragmentation under sustained land-use modification and climate change.

AbstractAbstract. neighboring countries. Recently, an increase in biological surveys and access to natural preserves has led to a better understanding of species distributions in Nicaragua and across Central America. Here, we provide new departmental records for three species of didelphid, 18 chiropterans (Phyllostomidae, Molossidae, Vespertilionidae), one geomyid, and one mustelid from 21 sites across the country. This work underscores the need for additional sampling across Nicaragua to fill gaps in the known distribution of many species. This information can facilitate or inform conservation actions in established and proposed preserves in Nicaragua.

Landoltia punctata is an invasive aquatic plant that has spread across the United States. Unlike native duckweeds, this species has developed herbicide resistance. As a result, invasion can lead to high management costs and the loss of recreational areas and natural habitats. The species has been recently found in Europe, and is also approaching the northern US border with Canada. We predicted the potential distribution of L. punctata in western Europe and Canada using presence-only data from the Global Biodiversity Information Facility as well as other literature records. We fit predictive models to this data using a Maxent approach. Since climate data based on surface lake water conditions are often more relevant to macrophytes than air temperature metrics, our models included both water and air temperature bioclimatic variables related to the life history of the species. Model comparisons confirmed a superior fit of lake temperatures to duckweed distribution records. The best fit model suggests a high habitat suitability for the species in most Western European countries and Western Canada. A moderate emission scenario suggests that in 2041 currently compatible areas will still be suitable, and that the Great Lakes region will become suitable. Preventive measures to avoid future spread of L. punctata are recommended in these locations to avoid impacts associated with this and similar duckweed species in Europe and the US.

Species range shifts due to changing ocean conditions are occurring around the world. As species move, they build new interaction networks as they shift from or into new ecological communities. Typically, species ranges are modeled individually, but biotic interactions have been shown to be important to creating more realistic modeling outputs for species. To understand the importance of consumer interactions in Eastern Pacific kelp forest species distributions, we used a Maxent framework to model a key foundation species, giant kelp (Macrocystis pyrifera), and a dominant herbivore, purple sea urchins (Strongylocentrotus purpuratus). With neither species having previously been modeled in the Eastern Pacific, we found evidence for M. pyrifera expansion in the northern section of its range, with no projected contraction at the southern range edge. Despite its known co-occurrence with M. pyrifera, models of S. purpuratus showed a non-concurrent southern range contraction and a co-occurring northern range expansion. While the co-occurring shifts may lead to increased spatial competition for suitable substrate, this non-concurrent contraction could result in community wide impacts such as herbivore release, tropicalization, or ecosystem restructuring.

Understanding and mitigating the effects of anthropogenic climate change on species distributions requires the ability to track range shifts over time. This is particularly true for species occupying high-latitude regions, which are experiencing more extreme climate change than the rest of the world. In North America, the geographic ranges of many mammals reach their northernmost extent in Alaska, positioning this region at the leading edge of climate-induced distribution change. Over a decade has elapsed since the publication of the last spatial assessments of terrestrial mammals in the state. We compared public occurrence records against commonly referenced range maps to evaluate potential extralimital records and develop repeatable baseline range maps. We compared occurrence records from the Global Biodiversity Information Facility for 61 terrestrial mammal species native to mainland Alaska against a variety of range estimates (International Union for Conservation of Nature, Alaska Gap Analysis Project, and the published literature). We mapped extralimital records and calculated proportions of occurrences encompassed by range extents, measured mean direction and distance to prior range margins, evaluated predictive accuracy of published species models, and highlighted observations on federal lands in Alaska. Range comparisons identified 6,848 extralimital records for 39 of 61 (63.9%) terrestrial mainland Alaskan species. On average, 95.5% of Alaska Gap Analysis Project occurrence records and ranges were deemed accurate (i.e., > 90.0% correct) for 31 of 37 species, but overestimated extents for 13 species. The International Union for Conservation of Nature range maps encompassed 68.1% of occurrence records and were > 90% accurate for 17 of 39 species. Extralimital records represent either improved sampling and digitization or actual geographic range expansions. Here we provide new data-driven range maps, update standards for the archiving of museum-quality locational records and offer recommendations for mapping range changes for monitoring and conservation.

Context Shifts in climate and land use have dramatically reshaped ecosystems, impacting the distribution and status of wildlife populations. For many species, data gaps limit inference regarding population trends and links to environmental change. This deficiency hinders our ability to enact meaningful conservation measures to protect at risk species. Objectives We investigated historical drivers of environmental niche change for three North American weasel species (American ermine, least weasel, and long-tailed weasel) to understand their response to environmental change. Methods Using species occurrence records and corresponding environmental data, we developed species-specific environmental niche models for the contiguous United States (1938–2021). We generated annual hindcasted predictions of the species’ environmental niche, assessing changes in distribution, area, and fragmentation in response to environmental change. Results We identified a 54% decline in suitable habitat alongside high levels of fragmentation for least weasels and region-specific trends for American ermine and long-tailed weasels; declines in the West and increased suitability in the East. Climate and land use were important predictors of the environmental niche for all species. Changes in habitat amount and distribution reflected widespread land use changes over the past century while declines in southern and low-elevation areas are consistent with impacts from climatic change. Conclusions Our models uncovered land use and climatic change as potential historic drivers of population change for North American weasels and provide a basis for management recommendations and targeted survey efforts. We identified potentially at-risk populations and a need for landscape-level planning to support weasel populations amid ongoing environmental changes.

Cerrado is a large and heterogeneous ecoregion in the Neotropics marked by the fire‐prone savanna vegetation, to which succulent lineages are usually not associated due to this adverse condition. However, recent studies have highlighted the importance of Cerrado as an ancestral range for the origin, dispersal and in situ diversification of remarkable lineages of South American cacti. In this perspective, we explore the implications of these occurrences in the Cerrado, shedding light on a frequently overlooked aspect of this ecoregion—the role of scattered rocky outcrop habitats acting as micro‐refuges for fire‐sensitive lineages. We show that most cacti occurrences are associated with patches of rock outcrops across the Cerrado. In contrast, when terricolous, a few disparate and not closely related species can develop underground structures or present a specialized habit that facilitates their presence as a putative response to fire—reinforcing the evolutionary lability of fire adaptation in Cerrado lineages. Despite some notable endemisms, several occurrences are from species with core distributions in adjacent ecoregions (e.g. Caatinga and Chaco), demonstrating the permeability of Cerrado, which can act concomitantly as a biogeographical barrier (especially due to its fire‐prone habitats) and as a corridor for biota interchange. Finally, we stress that Cerrado heterogeneity, often leading to different circumscriptions, is a relevant issue when studying and characterizing Neotropical biota, which must be further explored and considered to assess the evolutionary assembly of the biomes involved.

Aim To test the hypothesis that adaptive shifts leading to the assembly of tropical savannas involved coordination between bark and wood traits and to understand the underlying mechanisms.LocationTropical South America.TaxonAngiosperms (woody).MethodsWe compiled data on three bark traits (total, inner and outer relative bark thickness), wood density, maximum height, five secondary xylem traits and on species' habitat information (light environment, climate, soil and fire history) for Neotropical savanna, forest and generalist species (biome groups). We tested for pairwise and multivariate associations among traits across species and if biome group and habitat conditions explained species positions along the resulting strategy axes.ResultsTraits covaried along four different axes. The first axis was consistent with a trade‐off between fire (thick barks) and shade tolerance (low bark to diameter ratio, high vessel density) and contributed to differentiate the three biome groups according to the preference for shaded environments. Forest species also differed from savanna and generalist species in a separate axis by being more resource acquisitive. Maximum height and wood density did not strongly trade‐off with bark thickness, although maximum height was negatively covaried with relative outer bark thickness. Preference for shaded conditions was the main driver of variation in the two principal strategy axes, but temperature, fire and soil sand content also explained differences in plant stature between savanna and generalist species.Main ConclusionsAllocation to bark is constrained by trade‐offs with wood, opposing shade‐tolerant and acquisitive forest species to fire‐resistant and conservative savanna species. Rather than a single strategy axis, three axes are necessary to understand the functional differences among savanna, forest and generalist species. Because two of these axes are controlled by light availability, the associated traits tend to covary in space and time, but not across species.