Science Enabled by Specimen Data

Bürger, M., and J. Chory. 2024. A potential role of heat‐moisture couplings in the range expansion of Striga asiatica. Ecology and Evolution 14. https://doi.org/10.1002/ece3.11332

Parasitic weeds in the genera Orobanche, Phelipanche (broomrapes) and Striga (witchweeds) have a devastating impact on food security across much of Africa, Asia and the Mediterranean Basin. Yet, how climatic factors might affect the range expansion of these weeds in the context of global environmental change remains unexplored. We examined satellite‐based environmental variables such as surface temperature, root zone soil moisture, and elevation, in relation to parasitic weed distribution and environmental conditions over time, in combination with observational data from the Global Biodiversity Information Facility (GBIF). Our analysis reveals contrasting environmental and altitude preferences in the genera Striga and Orobanche. Asiatic witchweed (Striga asiatica), which infests corn, rice, sorghum, and sugar cane crops, appears to be expanding its range in high elevation habitats. It also shows a significant association with heat‐moisture coupling events, the frequency of which is rising in such environments. These results point to geographical shifts in distribution and abundance in parasitic weeds due to climate change.

Köhler, M., M. Romeiro‐Brito, and M. Telhe. 2024. The Cerrado through cacti. Journal of Biogeography. https://doi.org/10.1111/jbi.14846

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.

Dantas, V. L., L. C. S. Oliveira, C. R. Marcati, and J. Sonsin‐Oliveira. 2024. Coordination of bark and wood traits underlies forest‐to‐savanna evolutionary transitions. Journal of Biogeography. https://doi.org/10.1111/jbi.14850

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.

Peralta, P. A., M. J. Nores, H. G. Bach, and F. O. Robbiati. 2024. Facing climate change: Range dynamics and chromosome diversity in Hedeoma multiflora Benth., a South American aromatic-medicinal plant at risk. Flora 315: 152519. https://doi.org/10.1016/j.flora.2024.152519

Climate change could significantly affect the geographic distribution of plant species. Hedeoma multiflora is a vulnerable medicinal and aromatic herb that distributes in the Pampa, Espinal and Chaco biogeographic provinces in austral South America. This integrated approach combines ecological models and cytogenetic evidence to assess the effects of climate change on this species. Species distribution modelling using the Maxent model was implemented under current climatic conditions and three future climate change scenarios, integrating data from three Global Climate Models. The most suitable areas span 68,557 km2, encompassing the Sierras Pampeanas in San Luis and Córdoba provinces, and the Tandilia and Ventania systems in Buenos Aires, Argentina. The primary variables influencing the models include elevation (500 to 2000 m.a.s.l.), annual mean temperature (10 to 17 °C), annual precipitation (500 to 900 mm) and precipitation seasonality (50 to 75%). While the results project an expansion in the potential distribution of the species, heterogeneous patterns of range shifts are predicted across the three mountain systems: expansion in Sierras Pampeanas, march in Ventania and retraction in the Tandilia system. Variations in chromosome numbers within four distinct localities were reported, indicating the presence of polyploidy. This could potentially provide adaptive advantages in response to changing climates. This plant lives in habitats that face human-induced alterations and insufficient area protected coverage, then we propose strategies for both in situ and ex situ conservation of this medicinal species in each area.

Minghetti, E., P. M. Dellapé, and S. I. Montemayor. 2024. Orsillus depressus (Heteroptera: Lygaeidae), an invasive circum-mediterranean species recently reported from America. Are the endemic and already endangered Cupressaceae trees from the Andean Region facing a new challenge? Biological Invasions. https://doi.org/10.1007/s10530-024-03313-6

Orsillus depressus , a circum-mediterranean species of seed bug that lives on several genera and species of Cupressaceae is considered a pest of these trees, has recently been recorded for the first time in America, in Argentina. As the western records of O. depressus are close to endemic Cupressaceae forests from the Andean Region, our attention is drawn to the possible risk of colonization and establishment of O. depressus on these forests, where three endemic monotipic genera are found: Austrocedrus chilensis , Fitzroya cupressoides and Pilgerodendron uviferum . Maxent Models for present and future scenarios, and Minimum Volume Ellipsoids were used, and natural pathways were explored. Orsillus depressus has shown a high adaptive capacity to environments with different climates, and considering the models predictions, there are large suitable areas for its establishment in southern Argentina and Chile. Also, the climatic space O. depressus occupies is small and in part new, and an expansion should be expected. Moreover, multiple natural pathways were recognized that would allow its ingression in areas highly suitable with endemic Cupressaceae forests.

Ziegler, C., E. J. Martínez, A. I. Honfi, and A. V. Reutemann. 2024. Discovery of natural Paspalum L. (Poaceae) triploid hybrids near sympatric populations of Paspalum urvillei Steud. and species of Paniculata group in northeastern Argentina. Euphytica 220. https://doi.org/10.1007/s10681-024-03317-2

Hybridization and polyploidy are currently known as exponential factors for biodiversity. Some Paspalum species can hybridize and originate viable allopolyploids with possible agronomic use. We collected a frost resistance hybrid in north–western Misiones and determined its ploidy level, meiotic behavior, pollen viability, cytoembryology, and seed production in open and self-pollination. To elucidate its origin, we conducted a phenotypic and geographical analysis using herbarium specimens to establish its putative parental species. The hybrid was triploid, exhibiting irregular meiosis with the formation of non-viable pollen and undeveloped embryo sacs, resulting in very low seed production under both pollination conditions. Through morphological analysis, we identified Paspalum urvillei Steud. and the Paniculata group, i.e. Paspalum juergensii Hack., Paspalum umbrosum Trin., and Paspalum paniculatum L., as the putative parental species. Geographic distribution patterns suggested a possible hybridization event between P. urvillei and P. umbrosum , though further investigation is needed to precisely identify which species from the Paniculata group hybridized with P. urvillei. Future studies will help to unravel the complex genetic interactions underlying hybridization in Paspalum species and contribute to our understanding of biodiversity dynamics.

Estrada-Sánchez, I., A. Espejo-Serna, J. García-Cruz, and A. R. López-Ferrari. 2024. Richness, distribution, and endemism of neotropical subtribe Ponerinae (Orchidaceae, Epidendreae). Brazilian Journal of Botany 47: 501–517. https://doi.org/10.1007/s40415-024-01005-y

The subtribe Ponerinae (Orchidaceae) includes the genera Helleriella A. D. Hawkes, Isochilus R. Brown, Nemaconia Knowles & Westc., and Ponera Lindl. Most of its species are epiphytes and usually grow on trees of the genus Quercus L. in cloud forests and temperate coniferous and broad-leaved forests; some taxa are rarely lithophytes or less frequently terrestrial. The aim of this study was to estimate the distribution of the species of the subtribe Ponerinae using ecological niche models (ENM), determine areas with highest richness and endemism rates with the occurrence data and the models obtained, and determine if the areas with highest richness and endemism recognized in this work are located within any of the conservation areas (ANPs) and/or Regiones Terrestres Prioritarias (RTPs). We reviewed 1 044 herbarium specimens from ten institutional collections, corresponding to two species of Helleriella , eleven of Isochilus , six of Nemaconia , and two of Ponera , and a geographic and taxonomic database was generated. ENM were constructed with MaxEnt 3.3; and we determine areas with highest species richness and endemism with Biodiverse 4.3. Mexico is the richest country with 21 species, followed by Guatemala with nine. The more widely distributed species are: Isochilus linearis (Jacq.) R.Br, and Nemaconia striata (Lindl.) Van den Berg, Salazar & Soto Arenas; I . oaxacanus Salazar & Soto Arenas is endemic to Mexican state of Oaxaca and N . dressleriana (Soto Arenas) van den Berg, Salazar & Soto Arenas of Morelos. The cells with higher occurrence richness and occurrence weighted endemism were located in Chiapas Highlands, and the higher occurrence of corrected weighted endemism is located in Transmexican Volcanic Belt, considered the nucleus of the Mexican Transition Zone. On the other hand, the cells with greater ENM richness and ENM weighted endemism were located in Sierra Madre del Sur, and the higher ENM corrected weighted endemism in Sierra Madre Oriental. It is suggested to change the status of the regions Cañón del Zopilote and El Tlacuache from RTPs to ANPs.

Serra‐Diaz, J. M., J. Borderieux, B. Maitner, C. C. F. Boonman, D. Park, W. Guo, A. Callebaut, et al. 2024. occTest: An integrated approach for quality control of species occurrence data. Global Ecology and Biogeography. https://doi.org/10.1111/geb.13847

Aim Species occurrence data are valuable information that enables one to estimate geographical distributions, characterize niches and their evolution, and guide spatial conservation planning. Rapid increases in species occurrence data stem from increasing digitization and aggregation efforts, and citizen science initiatives. However, persistent quality issues in occurrence data can impact the accuracy of scientific findings, underscoring the importance of filtering erroneous occurrence records in biodiversity analyses.InnovationWe introduce an R package, occTest, that synthesizes a growing open‐source ecosystem of biodiversity cleaning workflows to prepare occurrence data for different modelling applications. It offers a structured set of algorithms to identify potential problems with species occurrence records by employing a hierarchical organization of multiple tests. The workflow has a hierarchical structure organized in testPhases (i.e. cleaning vs. testing) that encompass different testBlocks grouping different testTypes (e.g. environmental outlier detection), which may use different testMethods (e.g. Rosner test, jacknife,etc.). Four different testBlocks characterize potential problems in geographic, environmental, human influence and temporal dimensions. Filtering and plotting functions are incorporated to facilitate the interpretation of tests. We provide examples with different data sources, with default and user‐defined parameters. Compared to other available tools and workflows, occTest offers a comprehensive suite of integrated tests, and allows multiple methods associated with each test to explore consensus among data cleaning methods. It uniquely incorporates both coordinate accuracy analysis and environmental analysis of occurrence records. Furthermore, it provides a hierarchical structure to incorporate future tests yet to be developed.Main conclusionsoccTest will help users understand the quality and quantity of data available before the start of data analysis, while also enabling users to filter data using either predefined rules or custom‐built rules. As a result, occTest can better assess each record's appropriateness for its intended application.

Ramírez-Barahona, S. 2024. Incorporating fossils into the joint inference of phylogeny and biogeography of the tree fern order Cyatheales R. Warnock, and M. Zelditch [eds.],. Evolution. https://doi.org/10.1093/evolut/qpae034

Present-day geographic and phylogenetic patterns often reflect the geological and climatic history of the planet. Neontological distribution data are often sufficient to unravel a lineage’s biogeographic history, yet ancestral range inferences can be at odds with fossil evidence. Here, I use the fossilized birth–death process and the dispersal–extinction cladogenesis model to jointly infer the dated phylogeny and range evolution of the tree fern order Cyatheales. I use data for 101 fossil and 442 extant tree ferns to reconstruct the biogeographic history of the group over the last 220 million years. Fossil-aware reconstructions evince a prolonged occupancy of Laurasia over the Triassic–Cretaceous by Cyathealean tree ferns, which is evident in the fossil record but hidden from analyses relying on neontological data alone. Nonetheless, fossil-aware reconstructions are affected by uncertainty in fossils’ phylogenetic placement, taphonomic biases, and specimen sampling and are sensitive to interpretation of paleodistributions and how these are scored. The present results highlight the need and challenges of incorporating fossils into joint inferences of phylogeny and biogeography to improve the reliability of ancestral geographic range estimation.

Souto, C. P., L. P. Zalazar, M. Tadey, and A. C. Premoli. 2024. Modeling past, present and future: Species-specific responses to climate changes in three shrub congeners from south American drylands. Journal of Arid Environments 221: 105139. https://doi.org/10.1016/j.jaridenv.2024.105139

Drylands cover ca. 40% of the land global surface and deliver significant ecosystem services. These regions are the most sensitive, prone to suffer the effects of climate and distribution changes, so estimates on projected range shifts are crucial to complement traditional approaches to biodiversity conservation and sustainability. Shrubs of the Monte Desert dominate the largest temperate dryland in South America. Our goal is to assess the spatial distribution and niche overlap of three native shrubs (Larrea cuneifolia (LC), L. divaricata (LD), and L. nitida (LN)), under present climate conditions, to retrodict their potential past distribution, and anticipate their predicted range under future climate scenarios. We used ecological niche modeling that were projected to the past (LGM and Mid Holocene) and future (2050 and 2070) under two scenarios of greenhouse gas emissions and two model of global circulation. All species have high niche overlap (67–89%), but showed species-specific responses, highlighting the need to develop mitigation measures particularly for LD and LN in the face of climate change and land use pressures. Global South deserts are being highly degraded and information on future potential ranges of endemic species can support the development of sustainable conservation and management plans.