Science Enabled by Specimen Data
Brock, J. M. R., A. M. Bellvé, and B. R. Burns. 2025. Marcescence and prostrate growth in tree ferns are adaptations to cold tolerance. Ecography. https://doi.org/10.1111/ecog.07362
Cold tolerance strategies in plants vary from structural to biochemical permitting many plants to survive and grow on sites that experience freezing conditions intermittently. Although tree ferns occur predominantly across the tropics, they also occur in temperate zones and occasionally in areas that experience sub‐zero temperatures, and how these large ferns survive freezing conditions is unknown. Many temperate tree fern taxa are marcescent – retaining whorls of dead fronds encircling the upper trunk – or develop short or prostrate trunks, possibly to insulate against frost damage to their trunks and growing crowns. We asked the following questions: 1) do global growth patterns and traits of tree ferns respond to freezing conditions associated with latitude and elevation, 2) do growth patterns of tree ferns in New Zealand vary along a temperature‐related gradient, and 3) do marcescent tree fern skirts insulate the growing crown from sub‐zero temperatures? To establish what morphological adaptations permitted the Cyatheales to occur in biomes that experience intermittent sub‐zero temperatures and frost, we 1) reviewed the global distributions of these structural and morphological traits within the tree ferns (Cyatheales); 2) assessed the patterns of tree fern marcescence, and other traits potentially associated with cold tolerance (no trunk, prostrate, short‐trunked) of nine taxa of the Cyatheales along environmental gradients across New Zealand; and 3) conducted a field experiment to assess the thermal insulation properties of tree fern marcescent skirts. We identified significant trends among growth forms, marcescence, and environmental gradients consistent with our hypothesis that these are adaptations to tolerate cold. Our field experiments provide quantitative evidence that marcescent skirts have a strong insulating effect on tree fern trunks. The Cyatheales have evolved several strategies to protect the pith cores of their trunks from extreme cold temperatures in temperate forests allowing them to capture niche space in environments beyond the tropics.
Wogan, G. O. U., G. Voelker, T. Jain, P. Kaliba, and R. C. K. Bowie. 2024. Niche dynamics modulate population connectivity between disjunct ranges of the Cape Robin-chat (Cossypha caffra) supporting an aridlands species pump. Frontiers of Biogeography 17. https://doi.org/10.21425/fob.17.132679
Southern Africa boasts an extraordinary diversity of birds, posited to have at least in part been driven by a “species pump” model, facilitated by an intermittent arid corridor connecting it with northeast Africa. This arid corridor arose and disappeared in concert with Plio-Pleistocene climate fluctuations, providing a means for northern, primarily arid-adapted lineages, to disperse to and subsequently colonize Southern Africa. Here, we test this “species pump” at the intra-specific level. We focus on Cape Robin-chats (Cossypha caffra) which have disjunct resident populations in the forested mountains of East Africa and in the aridlands of Southern Africa. We use multi-locus data to estimate gene flow between these populations, model spatial connectivity across this region contemporaneously and over the past 120 thousand years, and test niche differentiation. We found evidence for highly asymmetric gene flow (north to south) among Cape Robin-chat populations, and niche differentiation coupled with an inferred niche-based environmental filter limiting gene flow from southern to northern populations. Habitat suitability supports the presence of an intermittent corridor stretching from the Horn of Africa to Southern Africa. We propose that a modified species pump incorporating niche divergence and subsequent dispersal limitation driven by environmental filters has contributed to population differentiation among northern and southern populations of Cape Robin-chats, and that this same mechanism over time may have contributed to the rich avifaunal diversity of Southern Africa. Southern Africa has rich avifauna with high endemicity driven in part by in situ speciation. Using a combination of genetic analyses, niche models, and dispersal models, we find support for an intermittent aridlands corridor between disjunct populations of Cape Robin-chats modulated by Plio-Pleistocene climatic oscillations. This study shows niche divergence and asymmetric gene flow between southern and northern populations, providing a mechanism for population divergence. This supports the existence of an aridlands species pump that drives population divergence and may have contributed to species diversification in the Southern Africa avifauna.
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.
Viljoen, N., J. Weyer, J. Coertse, and W. Markotter. 2023. Evaluation of Taxonomic Characteristics of Matlo and Phala Bat Rabies-Related Lyssaviruses Identified in South Africa. Viruses 15: 2047. https://doi.org/10.3390/v15102047
We report the genetic characterization of two potentially novel rabies-related lyssaviruses identified from bats in Limpopo province, South Africa. Matlo bat lyssavirus (MBLV) was identified in two Miniopterus natalensis (Natal long-fingered) bats in 2015 and 2016, and Phala bat lyssavirus (PBLV) was identified in a Nycticeinops schlieffeni (Schlieffen’s) bat in 2021. The distribution of both of these bat species is largely confined to parts of Africa, with limited reports from the Arabian Peninsula. MBLV and PBLV were demonstrated to group with the unassigned and phylogroup I lyssaviruses, respectively. MBLV was most closely related to Lyssavirus caucasicus (WCBV), whereas PBLV was most closely related to Lyssavirus formosa (TWBLV-1) and Taiwan bat lyssavirus 2 (TWBLV-2), based on analysis of the N and G genes, the concatenated N + P + M + G + L coding sequence, and the complete genome sequence. Based on our analysis, MBLV and WCBV appeared to constitute a phylogroup separate from Lyssavirus lleida (LLEBV) and Lyssavirus ikoma (IKOV). Analysis of the antigenic sites suggests that PBLV will likely be serologically distinguishable from established lyssaviruses in virus-neutralization tests, whereas MBLV appeared to be antigenically highly similar to WCBV. Taken together, the findings suggested that, while PBLV is likely a new lyssavirus species, MBLV is likely related to WCBV.
Pahad, G., B. Jansen van Vuuren, and C. Montgelard. 2023. Palaeoclimatic niche modelling reveals the phylogeographic history of the South African shrew Myosorex varius and the colonisation route of the genus Myosorex (Mammalia, Soricidae) from East Africa. Mammalian Biology. https://doi.org/10.1007/s42991-023-00377-0
Myosorex varius is a South African generalist shrew, which has been found to consist of several genetic clades across its range. A northern clade inhabits the more mesic, summer-rainfall areas of grassland and savannah in the east of South Africa. A southern clade occupies areas of fynbos in the south, and can be further divided into a western subclade occupying winter-rainfall areas and an eastern subclade occupying areas with aseasonal rainfall. Non-South-African members of the African genus Myosorex primarily are limited to isolated montane habitats along the East African Rift System. Here, we used palaeoclimatic niche modelling to examine the effects of Pliocene and Pleistocene climate change on the distributions of M. varius , its clades and the genus as a whole. Results indicate that repeated cycles of range expansion during glacial periods and fragmentation during interglacials are responsible for current phylogeographic patterns within M. varius . Based on their close alignment with rainfall zones and lack of genetic mixing despite areas of contact, it is likely that these (sub)clades are locally adapted to their respective areas. Earlier climatic fluctuations allowed the genus to ‘island hop’ south from East Africa along the East African Rift System, expanding in range during cooler periods and retreating to montane refugia during warmer periods. Areas currently occupied by Myosorex species largely correspond with predicted montane refugia that have allowed them to survive previous warm periods.
Hamer, M., M. Kgatla, and B. Petersen. 2023. An assessment of collection specimen data for South African mountain plants and invertebrates. Transactions of the Royal Society of South Africa: 1–19. https://doi.org/10.1080/0035919x.2023.2200742
South Africa is considered a megadiverse country, with exceptionally high plant and relatively high animal species richness and endemism. The country’s species have been surveyed and studied for over 200 years, resulting in extensive natural science collections and a vast number of scientific papers and books. This study assessed whether existing data portals provide access to occurrence data and investigated the extent of the data in Global Biodiversity Information Facility and its completeness for plants and selected invertebrate taxa. The main focus was preserved specimen data, but some observation data from iNaturalist were also considered for selected analyses. Records that include species-level identification and co-ordinates were mapped in QGIS to show the coverage of collection localities across the country. The records that fall within the mountain range spatial layer were then extracted and counted to identify density of records per mountain range for various taxa. Forty percent of plant records are from mountain localities, and the Atlantic Cape Fold Mountains had the highest density of records. Table Mountain has been extensively collected for plants and invertebrates. A large proportion of the records for invertebrates lacked species-level identification and co-ordinates, resulting in a low number of records for analyses. The accessible data are only a relatively small subset of existing collections, and digitisation and data upgrading is considered a high priority before collecting gaps can be addressed by targeted surveys.
Hausdorf, B. 2023. Rapid increase in knowledge about the distribution of introduced predatory Testacella species (Gastropoda: Stylommatophora) in North America by community scientists. Biological Invasions. https://doi.org/10.1007/s10530-023-03071-x
Testacellidae are a group of carnivorous semislugs with a vestigial ear-shaped shell near the posterior end of their elongate bodies. The single genus Testacella is native to the western Mediterranean and western Europe, but some species have been introduced into temperate countries worldwide. The species are subterranean and feed on earthworms. Due to their predominantly subterranean lifestyle, Testacella species are difficult to observe. Here, I review of the distribution of introduced Testacella species in North America and compare the knowledge based on literature references and museum specimens collected over more than a century with that observed by community scientists on the web platform iNaturalist in less than 10 years. Literature references and museum specimens indicate scattered occurrences of the introduced Testacella haliotidea in the eastern USA and a few more occurrences in the Pacific states of the USA and in British Columbia. Community scientists have nearly replicated a century of knowledge about the distribution of Testacella in North America. Their records even show a more continuous distribution of T. haliotidea in the Pacific states and confirm its presence in Tennessee, but not yet in Pennsylvania. They also provided the first records of T. haliotidea in Georgia and Mexico, and discovered a second introduced Testacella species, Testacella maugei , in California. The most distant occurrences of T. maugei in California are about 100 km apart, indicating that the species was probably introduced several years ago.
Clemente, K. J. E., and M. S. Thomsen. 2023. High temperature frequently increases facilitation between aquatic foundation species: a global meta‐analysis of interaction experiments between angiosperms, seaweeds, and bivalves. Journal of Ecology. https://doi.org/10.1111/1365-2745.14101
Many studies have quantified ecological impacts of individual foundation species (FS). However, emerging data suggest that FS often co‐occur, potentially inhibiting or facilitating one another, thereby causing indirect, cascading effects on surrounding communities. Furthermore, global warming is accelerating, but little is known about how interactions between co‐occurring FS vary with temperature.Shallow aquatic sedimentary systems are often dominated by three types of FS: slower‐growing clonal angiosperms, faster‐growing solitary seaweeds, and shell‐forming filter‐ and deposit‐feeding bivalves. Here, we tested the impacts of one FS on another by analyzing manipulative interaction experiments from 148 papers with a global meta‐analysis.We calculated 1,942 (non‐independent) Hedges’ g effect sizes, from 11,652 extracted values over performance responses, such as abundances, growths or survival of FS, and their associated standard deviations and replication levels. Standard aggregation procedures generated 511 independent Hedges’ g that was classified into six types of reciprocal impacts between FS.We found that (i) seaweeds had consistent negative impacts on angiosperms across performance responses, organismal sizes, experimental approaches, and ecosystem types; (ii) angiosperms and bivalves generally had positive impacts on each other (e.g., positive effects of angiosperms on bivalves were consistent across organismal sizes and experimental approaches, but angiosperm effect on bivalve growth and bivalve effect on angiosperm abundance were not significant); (iii) bivalves positively affected seaweeds (particularly on growth responses); (iv) there were generally no net effects of seaweeds on bivalves (except for positive effect on growth) or angiosperms on seaweeds (except for positive effect on ‘other processes’); and (v) bivalve interactions with other FS were typically more positive at higher temperatures, but angiosperm‐seaweed interactions were not moderated by temperature.Synthesis: Despite variations in experimental and spatiotemporal conditions, the stronger positive interactions at higher temperatures suggest that facilitation, particularly involving bivalves, may become more important in a future warmer world. Importantly, addressing research gaps, such as the scarcity of FS interaction experiments from tropical and freshwater systems and for less studied species, as well as testing for density‐dependent effects, could better inform aquatic ecosystem conservation and restoration efforts and broaden our knowledge of FS interactions in the Anthropocene.
Higino, G. T., F. Banville, G. Dansereau, N. R. Forero Muñoz, F. Windsor, and T. Poisot. 2023. Mismatch between IUCN range maps and species interactions data illustrated using the Serengeti food web. PeerJ 11: e14620. https://doi.org/10.7717/peerj.14620
Background Range maps are a useful tool to describe the spatial distribution of species. However, they need to be used with caution, as they essentially represent a rough approximation of a species’ suitable habitats. When stacked together, the resulting communities in each grid cell may not always be realistic, especially when species interactions are taken into account. Here we show the extent of the mismatch between range maps, provided by the International Union for Conservation of Nature (IUCN), and species interactions data. More precisely, we show that local networks built from those stacked range maps often yield unrealistic communities, where species of higher trophic levels are completely disconnected from primary producers. Methodology We used the well-described Serengeti food web of mammals and plants as our case study, and identify areas of data mismatch within predators’ range maps by taking into account food web structure. We then used occurrence data from the Global Biodiversity Information Facility (GBIF) to investigate where data is most lacking. Results We found that most predator ranges comprised large areas without any overlapping distribution of their prey. However, many of these areas contained GBIF occurrences of the predator. Conclusions Our results suggest that the mismatch between both data sources could be due either to the lack of information about ecological interactions or the geographical occurrence of prey. We finally discuss general guidelines to help identify defective data among distributions and interactions data, and we recommend this method as a valuable way to assess whether the occurrence data that are being used, even if incomplete, are ecologically accurate.
Hausdorf, B. 2023. Distribution patterns of established alien land snail species in the Western Palaearctic Region. NeoBiota 81: 1–32. https://doi.org/10.3897/neobiota.81.96360
AbstractEstablished alien land snail species that were introduced into the Western Palaearctic Region from other regions and their spread in the Western Palaearctic are reviewed. Thirteen of the 22 species came from North America, three from Sub-Saharan Africa, two from the Australian region, three probably from the Oriental Region and one from South America. The establishment of outdoor populations of these species was usually first seen at the western or southern rims of the Western Palearctic. Within Europe, the alien species usually spread from south to north and from west to east. The latitudinal ranges of the alien species significantly increased with increasing time since the first record of introduction to the Western Palearctic. The latitudinal mid-points of the Western Palaearctic and native ranges of the species are significantly correlated when one outlier is omitted. There is a general trend of poleward shifts of the ranges of the species in the Western Palaearctic compared to their native ranges. There are three reasons for these shifts: (1) the northward expansion of some species in Western Europe facilitated by the oceanic climate, (2) the impediment to the colonisation of southern latitudes in the Western Palaearctic due to their aridity and (3) the establishment of tropical species in the Mediterranean and the Middle East. Most of the species are small, not carnivorous and unlikely to cause serious ecological or economic damage. In contrast, the recently introduced large veronicellid slugs from Sub-Saharan Africa and the giant African snail Lissachatinafulica could cause economic damage in irrigated agricultural areas or greenhouses in the Mediterranean and the Middle East.