Science Enabled by Specimen Data

Hodgson, R. J., C. Liddicoat, C. Cando-Dumancela, N. W. Fickling, S. D. Peddle, S. Ramesh, and M. F. Breed. 2024. Increasing aridity strengthens the core bacterial rhizosphere associations in the pan-palaeotropical C4 grass, Themeda triandra. Applied Soil Ecology 201: 105514. https://doi.org/10.1016/j.apsoil.2024.105514

Understanding belowground plant-microbial interactions is fundamental to predicting how plant species respond to climate change, particularly in global drylands. However, these interactions are poorly understood, especially for keystone grass species like the pan-palaeotropical Themeda triandra. Here, we used 16S rRNA amplicon sequencing to characterise microbiota in rhizospheres and bulk soils associated with T. triandra. We applied this method to eight native sites across a 3-fold aridity gradient (aridity index range = 0.318 to 0.903 = 87 % global aridity distribution) in southern Australia. By examining the relative contributions of climatic, edaphic, ecological, and host specific phenotypic traits, we identified the ecological drivers of core T. triandra-associated microbiota. We show that aridity had the strongest effect on shaping these core microbiotas, and report that a greater proportion of bacterial taxa that were from the core rhizosphere microbiomes were also differentially abundant in more arid T. triandra regions. These results suggest that T. triandra naturally growing in soils under more arid conditions have greater reliance on rhizosphere core taxa than plants growing under wetter conditions. Our study underscores the likely importance of targeted recruitment of bacteria into the rhizosphere by grassland keystone species, such as T. triandra, when growing in arid conditions. This bacterial soil recruitment is expected to become even more important under climate change.

Maharaj, S., B. W. Cowie, M. J. Byrne, and N. Venter. 2024. Insights into the invasion of the moth catcher vine, Araujia sericifera (Apocynaceae), in South Africa. South African Journal of Botany 171: 517–528. https://doi.org/10.1016/j.sajb.2024.06.034

The moth catcher vine, Araujia sericifera Brotero (Apocynaceae), is a prevalent invader in many countries worldwide, where it has been reported to be a significant threat to biodiversity and agriculture. However, limited knowledge exists surrounding the ecology, invasion and impacts of A. sericifera in South Africa, challenging the implementation of management efforts. Therefore, this study sought to understand the vine's invasion within a South African context. To determine the density of A. sericifera in response to ecological and socio-economic predictors, its abundance along roads in 42 Johannesburg suburbs was measured. Additionally, A. sericifera abundance was recorded on foot within two nature reserves in Johannesburg, where density estimates were found to be 29 times higher than those obtained via roadside surveys. At a local scale, there was no evidence to indicate that vegetation, urban cover, and median household income influence A. sericifera density, suggesting that the vine establishes indiscriminately across Johannesburg. To determine whether this opportunistic behaviour was reflected in the vine's recruitment, its emergence rates in response to shaded and full-sun conditions were investigated. Seedling emergence was higher under shaded conditions (47.8%) than under full-sun (11%). Using MaxEnt models, environmental variables affecting the plant's distribution in South Africa were identified. Human disturbance had a permutation importance of 85.6%, indicating that A. sericifera's establishment is largely driven by disturbance. While A. sericifera appears to be in its lag phase of invasion and is unlikely to invade natural ecosystems in the short term, its abundance in the two nature reserves suggests that management should be prioritised during this lag phase, prior to its potential expansion into less-disturbed areas.

Forti, L. R., J. L. C. da Silva, E. A. Ferreira, and J. K. Szabo. 2024. The implications of estimating rarity in Brazilian reptiles from GBIF data based on contributions from citizen science versus research institutions. Integrative Conservation 3: 112–126. https://doi.org/10.1002/inc3.53

Understanding the distribution of rare species is important for conservation prioritisation. Traditionally, museums and other research institutions have served as depositories for specimens and biodiversity information. However, estimating abundance from these sources is challenging due to spatiotemporally biased collection methods. For instance, large‐bodied reptiles that are found near research institutions or in popular, easily accessible sites tend to be overrepresented in collections compared to smaller species found in remote areas. Recently, a substantial number of observations have been amassed through citizen (or community) science initiatives, which are invaluable for monitoring purposes. Given the unstructured nature of this sampling, these datasets are often affected by biases, such as taxonomic, spatial and temporal preferences. Therefore, analysing data from these two sources can lead to different abundance estimates. This study compiled data on Brazilian reptile species from the Global Information Biodiversity Facility (GBIF). It employed a community‐ecology approach to analyse data from research institutions and citizen science initiatives, separately and collectively, to assess taxonomic and spatial species coverage and predict species rarity. Using a 1‐degree hexagonal grid, we analysed the spatial distribution of reptile communities and calculated rarity indices for 754 reptile species. Our findings reveal that 87 species were exclusively recorded in the citizen science subset, while 212 were recorded only by research institutions. The number of observations per species in the citizen science data followed a Gambin distribution, which aligns with the expected pattern of abundance in natural communities, unlike the data from research institutions. This suggests that citizen science data may be a more accurate source for estimating species abundance and rarity. The discrepancies in rarity classifications between the datasets were likely due to differences in sample size and potentially other sampling parameters. Nevertheless, combining data collected by both research institutions and citizen science initiatives can help to fill knowledge gaps in reptile species occurrence, thus enhancing the foundation for conservation efforts on a national scale.

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.

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.

Kenar, N. 2024. Predicting the effect of climate change on the geographic range of the Mediterranean relict tree Liquidambar orientalis Mill. Nordic Journal of Botany. https://doi.org/10.1111/njb.04250

Climate change is anticipated to pose a significant danger to the habitats and spatial distribution of species in the Mediterranean region throughout the present century. The primary objective of this study was to predict the future geographic range of Liquidambar orientalis, commonly known as the oriental sweetgum under different climate change scenarios. This species is a relict riparian Mediterranean plant originating from the southwestern Anatolia region and Rhodos Island in Greece. To gain insights into the potential effects of climate change on the range of L. orientalis in the future, I used an ensemble modeling approach of species distribution models based on the shared socioeconomic pathways (SSP1‐2.6 and SSP5‐8.5 for the years 2035, 2055 and 2070). The models suggested that the level of precipitation during the wettest month has a crucial role in determining the occurrence of the oriental sweetgum tree. Future projections indicate that the oriental sweetgum will significantly contract its native distribution range due to warming and declining precipitation levels. The population of L. orientalis has previously undergone a decrease as a result of anthropogenic activity. Therefore, it is imperative to augment the degree of urgency in conservation endeavors for the oriental sweetgum species against the ramifications of human‐induced actions and the persistent effects of climate change.

Louw, G. J., L. J. Potgieter, and D. M. Richardson. 2024. Myoporum (Scrophulariaceae): Introduction, naturalization, and invasion of an enigmatic tree genus in South Africa. South African Journal of Botany 168: 529–541. https://doi.org/10.1016/j.sajb.2024.03.022

Myoporum is a genus of trees and shrubs native to the Northern Hemisphere that has been introduced to many parts of the world, mainly for ornamental purposes. We assessed the introduction history, distribution, and extent of naturalization/invasion for Myoporum species in South Africa.Information was collated to determine key events associated with the introduction, establishment, and naturalization of Myoporum in South Africa. Data were collated to determine the current distribution of the genus in South Africa. Twenty sites in the Western Cape were sampled to determine correlates of naturalization. Myoporum was first recorded in South Africa in 1934. Three species were confirmed to be present in South Africa: M. insulare, M. laetum and M. montanum (37 %, 25 % and 24 % of all iNaturalist records respectively). Most records are from the Western Cape (91 %) and small parts of the Eastern Cape; isolated populations occur in Gauteng and the Northern Cape. We could not confirm the presence M. petiolatum, M. tenuifolium or M. tetrandrum. Field surveys revealed widespread naturalization of M. insulare (46 % of all Research Grade observations in iNaturalist); this species was categorized code D1 in the introduction-naturalization-invasion continuum. Myoporum laetum (C3) and M. montanum (C2) are also widely naturalized but over smaller areas. Naturalized populations comprised predominantly juvenile M. insulare plants occurring in highly disturbed (transformed) habitats. Formal risk analyses for all Myoporum species in South Africa are needed as the basis for re-evaluation of their status in national legislation.

Barman, M., A. Barman, and S. Ray. 2024. Clerodendrum inerme (L.) Gaertn.: a critical review on current progress in traditional uses, phytochemistry, pharmacological aspects and toxicity. Phytochemistry Reviews. https://doi.org/10.1007/s11101-024-09934-y

Clerodendrum inerme (L.) Gaertn., commonly known as garden quinine, is a perennial shrub that belongs to the Lamiaceae family. It has been extensively used in various traditional medicinal practices to treat ailments such as rheumatic pain, arthritis, scrofulous, venereal disease, skin diseases, wounds, fever, cough, dysentery, and more. This review aims to critically examine a comprehensive compilation of recent research on C. inerme , encompassing its botanical characteristics, ethnomedical applications, phytochemicals, pharmacological activity, and toxicological data, in order to provide insights and inspiration for future research, promote further development, and facilitate the rational application of C. inerme. Nearly 95 chemical constituents belonging to different classes have been isolated from C. inerme , including diterpenoids, triterpenoids, steroids, flavonoids, phenolic glycosides, lignans, iridoid and megastigmane glycosides. Notably, diterpenoids, triterpenoids, steroids, and flavonoids are the main bioactive substances that have been extensively studied and demonstrated the most significant bioactivity. Pharmacological studies demonstrated that the extract of C. inerme exhibits a wide range of biological activities, such as antioxidant, antimicrobial, anticancer, antiinflammatory, insecticidal, antifeedant, neuroprotective, anti-motor tic, and so on, which are closely connected to its numerous ethnomedicinal applications. Nevertheless, some literature have reported the toxicity of C. inerme . Therefore, it is imperative to conduct further in-depth studies encompassing toxicology, as well as preclinical and clinical research, to ascertain the safety and efficacy of C. inerme for medicinal purposes. Graphical abstract

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.

Anest, A., Y. Bouchenak-Khelladi, T. Charles-Dominique, F. Forest, Y. Caraglio, G. P. Hempson, O. Maurin, and K. W. Tomlinson. 2024. Blocking then stinging as a case of two-step evolution of defensive cage architectures in herbivore-driven ecosystems. Nature Plants. https://doi.org/10.1038/s41477-024-01649-4

Dense branching and spines are common features of plant species in ecosystems with high mammalian herbivory pressure. While dense branching and spines can inhibit herbivory independently, when combined, they form a powerful defensive cage architecture. However, how cage architecture evolved under mammalian pressure has remained unexplored. Here we show how dense branching and spines emerged during the age of mammalian radiation in the Combretaceae family and diversified in herbivore-driven ecosystems in the tropics. Phylogenetic comparative methods revealed that modern plant architectural strategies defending against large mammals evolved via a stepwise process. First, dense branching emerged under intermediate herbivory pressure, followed by the acquisition of spines that supported higher speciation rates under high herbivory pressure. Our study highlights the adaptive value of dense branching as part of a herbivore defence strategy and identifies large mammal herbivory as a major selective force shaping the whole plant architecture of woody plants. This study explores the evolution of two traits, branching density and spine presence, in the globally distributed plant family Combretaceae. These traits were found to have appeared in a two-step process in response to mammalian herbivory pressure, revealing the importance of large mammals in the evolution of plant architecture diversity.