Science Enabled by Specimen Data
Coulibaly, A., H. G. G. Avakoudjo, R. Idohou, E. J. Vodounnon, S. Diallo, and M. Cherif. 2022. Impact of climate change on the distribution of Bombax costatum Pellegr. & Vuillet in Mali, West Africa. Trees, Forests and People: 100359. https://doi.org/10.1016/j.tfp.2022.100359
Bombax costatum is one of the multipurpose indigenous species in Mali, found in the Sudanian and Sudano-Guinean climatic zones with an important socio-economic contribution. This study assessed the potential impact of climate change on the geographic distribution of B. costatum in Mali, using the 19 bioclimatic variables downloaded from Worldclim at a 2.5 arc-minute resolution and 2013 occurrence points across west-Africa gathered from GBIF and fieldwork. The future niche of species was predicted using three climate models (CanESM5, CNRM-CM6, MIROC6) and four climatic scenarios (Shared Socioeconomic Pathways: SSP126; SSP245; SSP370 and SSP585) at two time periods (2021-2040 and 2041-2060). The study shows that the current suitable habitats for B. costatum species represent 10.780% of Mali territory. According to the climatic scenarios, the species distribution range especially its highly suitable areas will increase by 2040 and 2060. Moreover, the species could be found in some parts of the Sudano-Sahelian zone in the future. Therefore, sustainable management measures are necessary for B. costatum and should be integrated in reforestation policies to ensure its availability for its multiple uses in the coming years in Mali.
Dimobe, K., K. Ouédraogo, P. Annighöfer, J. Kollmann, J. Bayala, C. Hof, M. Schmidt, et al. 2022. Climate change aggravates anthropogenic threats of the endangered savanna tree Pterocarpus erinaceus (Fabaceae) in Burkina Faso. Journal for Nature Conservation: 126299. https://doi.org/10.1016/j.jnc.2022.126299
Species distribution modelling is gaining popularity due to significant habitat shifts in many plant and animal species caused by climate change. This issue is particularly pressing for species that provide significant ecosystem goods and services. A prominent case is the valuable African rosewood tree (Pterocarpus erinaceus) that is threatened in sub-Saharan Africa, while its present distribution, habitat requirements and the impact of climate change are not fully understood. This native species naturally occurs in various savanna types, but anthropogenic interventions have considerably reduced its natural populations in the past decades. In this study, ensemble modelling was used to predict the current and future distribution potential of the species in Burkina Faso. Fifty-four environmental variables were selected to describe its distribution in the years 2050 and 2070 based on the greenhouse gas concentration trajectories RCP4.5 and 8.5, and the general circulation models CNRM-CM5 and HadGEM2-CC. A network of protected areas in Burkina Faso was also included to assess how many of the suitable habitats may contribute to the conservation of the species. The factors isothermality (31%), minimum temperature of coldest month (31%), pH in H2O at horizon 0–5 cm (11%), silt content at horizon 60–100 cm (9.2%) and precipitation of warmest quarter (8%) were the most influential distribution drivers for the species. Under current climate conditions, potentially highly suitable habitats cover an area of 129,695 km2, i.e. 47% of Burkina Faso. The projected distribution under RCP4.5 and 8.5 showed that this area will decrease, and that the decline of the species will be pronounced. The two models used in this study forecast a habitat loss of up to 61% for P. erinaceus. Hence, development and implementation of a conservation program are required to save the species in its native range. This study will help land managers prioritise areas for protection of the species and avoid introducing it to inappropriate areas unless suitable conditions are artificially created through the management options applied.
Ripley, B. S., S. L. Raubenheimer, L. Perumal, M. Anderson, E. Mostert, B. S. Kgope, G. F. Midgley, and K. J. Simpson. 2022. CO 2 ‐fertilisation enhances resilience to browsing in the recruitment phase of an encroaching savanna tree. Functional Ecology. https://doi.org/10.1111/1365-2435.14215
CO2‐fertilisation is implicated in the widespread and significant woody encroachment of savannas due to CO2‐stimulated increases in belowground reserves that enhance sapling regrowth after fire. However, the effect of CO2 concentration ([CO2]) on tree responses to the other major disturbance in savannas, herbivory, is poorly understood. Herbivory‐responses cannot be predicted from fire‐responses, as herbivore effects occur earlier during establishment and are moderated by plant palatability and defence rather than belowground carbon accumulation.
Boeschoten, L. E., U. Sass-Klaassen, M. Vlam, R. N. J. Comans, G. F. Koopmans, B. R. V. Meyer-Sand, S. N. Tassiamba, et al. 2022. Clay and soil organic matter drive wood multi-elemental composition of a tropical tree species: Implications for timber tracing. Science of The Total Environment 849: 157877. https://doi.org/10.1016/j.scitotenv.2022.157877
Forensic methods to independently trace timber origin are essential to combat illegal timber trade. Tracing product origin by analysing their multi-element composition has been successfully applied in several commodities, but its potential for timber is not yet known. To evaluate this potential the drivers of wood multi-elemental composition need to be studied. Here we report on the first study relating wood multi-elemental composition of forest trees to soil chemical and physical properties.We studied the reactive soil element pools and the multi-elemental composition in sapwood and heartwood for 37 Azobé (Lophira alata) trees at two forest sites in Cameroon. A total of 46 elements were measured using ICP-MS. We also measured three potential drivers of soil and wood elemental composition: clay content, soil organic matter and pH. We tested associations between soil and wood using multiple regressions and multivariate analyses (Mantel test, db-RDA). Finally, we performed a Random Forest analysis of heartwood elemental composition to check site assignment accuracy.We found elemental compositions of soil, sapwood and heartwood to be significantly associated. Soil clay content and organic matter positively influenced individual element concentrations (for 13 and 9 elements out of 46 respectively) as well as the multi-elemental composition in wood. However, associations between wood and topsoil elemental concentrations were only significant for one element. We found close associations between element concentrations and composition in sapwood and heartwood. Lastly, the Random Forest assignment success was 97.3 %.Our findings indicate that wood elemental composition is associated with that in the topsoil and its variation is related to soil clay and organic matter content. These associations suggests that the multi-elemental composition of wood can yield chemical fingerprints obtained from sites that differ in soil properties. This finding in addition to the high assignment accuracy shows potential of multi-element analysis for tracing wood origin.
Vieira Araújo, F. H., A. Ferreira da Silva, R. S. Ramos, S. R. Ferreira, J. Barbosa dos Santos, R. Siqueira da Silva, and F. Shabani. 2022. Modelling climate suitability for Striga asiatica, a potential invasive weed of cereal crops. Crop Protection 160: 106050. https://doi.org/10.1016/j.cropro.2022.106050
Striga asiatica (Lamiales: Orobanchaceae), a hemi-parasitic plant native to sub-Saharan Africa and tropical Asia, is particularly problematic to rice, corn, and sorghum cultivation in Africa. Striga asiatica produces a large number of small sized (<0.5 mm) seeds, thereby facilitating easy dispersion by commercial exchange of contaminated grains. The distribution of this species in Africa is regulated by climate, which is the main factor determining local suitability. Modelling is a useful tool to analyse climate suitability for species. This study aimed to determine the areas more vulnerable to S. asiatica invasion both in the present and under the projected climate change model using two methods: MaxEnt (as a correlative approach) and CLIMEX (as a semi-mechanistic approach). The MIROC-H Global Climate Model and the A2 and RCP 8.5 scenarios (the most pessimistic one) were used. Our projections indicated areas suitable for S. asiatica invasion in all continents under both present and projected climate change, with high suitability areas in South America, Africa, and Europe. We found agreement and disagreement between CLIMEX and MaxEnt outputs and the extent of disagreement on the increases in climate suitability by 2050 and 2100 in North America, Europe, and eastern, southern, and western Australia. This study provides a useful tool to design strategies aimed at preventing the introduction and establishment of S. asiatica in South America, with considerable agreement between CLIMEX and MaxEnt outputs.
Hidalgo-Triana, N., F. Casimiro-Soriguer Solanas, A. Solakis Tena, A. V. Pérez-Latorre, and J. García-Sánchez. 2022. Melinis repens (Willd.) Zizka subsp. repens (Poaceae) in Europe: distribution, ecology and potential invasion. Botany Letters 169: 390–399. https://doi.org/10.1080/23818107.2022.2080111
Melinis repens subsp. repens is an annual herb native to Africa and southwestern Asia. In 2008, this species was detected growing in road verges and showing a reduced occupancy area of 6 km2 in a natural area of the southern Iberian Peninsula in the province of Malaga (Andalusia, Spain). The rest of the existing European records of this species comes from the Czech Republic, the Italian Peninsula, and Great Britain and can be considered casual. Furthermore, this species has become naturalised in Sardinia. The aim of this work is to study the invasion status, habitats, potential impacts, invasive behaviour, and pathways of introduction of Melinis repens subsp. repens in the southern Iberian Peninsula (Spain) to contribute to the control of this species. This species was most probably introduced into Europe for ornamental, fodder, or slope stabilization purposes. Our field work revealed this species has become naturalised in several habitats of Malaga and Granada provinces (Andalusia) occupying an area of 263 km2 in 2021. It behaves as a pioneer species that colonizes disturbed road margins and occurs in the same habitat as Cenchrus setaceus. Melinis repens subsp. repens can become dominant in natural EUNIS habitats and can also occupy cultivated areas. Because of the high occupancy area detected, and because the species has been assigned to the European Union List of Invasive Alien Plants based on the EPPO prioritization process, this plant should be considered the object of a control programme and its use should be legally prohibited in Spain, and more largely in European Mediterranean areas.
Catarino, S., D. Goyder, I. Darbyshire, E. Costa, R. Figueira, M. C. Duarte, and M. M. Romeiras. 2022. Species Diversity and Endemicity in the Angolan Leguminosae Flora. Frontiers in Ecology and Evolution 10. https://doi.org/10.3389/fevo.2022.871261
Angola has a great diversity of species and ecosystems and a high level of endemism. However, knowledge of the native flora remains very incomplete and outdated. Leguminosae is the largest family in the country, including many species which are of local or more regional economic importance. Based on an extensive review of bibliographic sources, natural history collections, and online databases, the checklist of Angolan Leguminosae plants was updated, including data on their native distribution, conservation status, and principal uses. The endemic taxa were the subject of additional investigation, including the main habitat, the number of collections preserved in herbaria, and the locality of the first collection. We identified 953 Leguminosae taxa occurring in Angola, of which 165 are endemic to the country. Among the 180 genera found, Crotalaria (136) and Indigofera (96) have the highest number of taxa. Almost half of the studied species have important applications, mainly in traditional medicine (385), forage (267), timber (188), and food (120). Nevertheless, only 27.7% have been assessed according to the IUCN Red List and 10 species are classified as threatened. Thirty-three endemics are known only from the type specimen, revealing the lack of knowledge on these species and the need for further field research. More than 30 type specimens were collected in the Serra da Chela, which highlights the importance of this region for biodiversity conservation.
Ramirez-Villegas, J., C. K. Khoury, H. A. Achicanoy, M. V. Diaz, A. C. Mendez, C. C. Sosa, Z. Kehel, et al. 2022. State of ex situ conservation of landrace groups of 25 major crops. Nature Plants 8: 491–499. https://doi.org/10.1038/s41477-022-01144-8
Crop landraces have unique local agroecological and societal functions and offer important genetic resources for plant breeding. Recognition of the value of landrace diversity and concern about its erosion on farms have led to sustained efforts to establish ex situ collections worldwide. The degree to which these efforts have succeeded in conserving landraces has not been comprehensively assessed. Here we modelled the potential distributions of eco-geographically distinguishable groups of landraces of 25 cereal, pulse and starchy root/tuber/fruit crops within their geographic regions of diversity. We then analysed the extent to which these landrace groups are represented in genebank collections, using geographic and ecological coverage metrics as a proxy for genetic diversity. We find that ex situ conservation of landrace groups is currently moderately comprehensive on average, with substantial variation among crops; a mean of 63% ± 12.6% of distributions is currently represented in genebanks. Breadfruit, bananas and plantains, lentils, common beans, chickpeas, barley and bread wheat landrace groups are among the most fully represented, whereas the largest conservation gaps persist for pearl millet, yams, finger millet, groundnut, potatoes and peas. Geographic regions prioritized for further collection of landrace groups for ex situ conservation include South Asia, the Mediterranean and West Asia, Mesoamerica, sub-Saharan Africa, the Andean mountains of South America and Central to East Asia. With further progress to fill these gaps, a high degree of representation of landrace group diversity in genebanks is feasible globally, thus fulfilling international targets for their ex situ conservation. By analysing the state of representation of traditional varieties of 25 major crops in ex situ repositories, this study demonstrates conservation progress made over more than a half-century and identifies the gaps remaining to be filled.
Williams, C. J. R., D. J. Lunt, U. Salzmann, T. Reichgelt, G. N. Inglis, D. R. Greenwood, W. Chan, et al. 2022. African Hydroclimate During the Early Eocene From the DeepMIP Simulations. Paleoceanography and Paleoclimatology 37. https://doi.org/10.1029/2022pa004419
The early Eocene (∼56‐48 million years ago) is characterised by high CO2 estimates (1200‐2500 ppmv) and elevated global temperatures (∼10 to 16°C higher than modern). However, the response of the hydrological cycle during the early Eocene is poorly constrained, especially in regions with sparse data coverage (e.g. Africa). Here we present a study of African hydroclimate during the early Eocene, as simulated by an ensemble of state‐of‐the‐art climate models in the Deep‐time Model Intercomparison Project (DeepMIP). A comparison between the DeepMIP pre‐industrial simulations and modern observations suggests that model biases are model‐ and geographically dependent, however these biases are reduced in the model ensemble mean. A comparison between the Eocene simulations and the pre‐industrial suggests that there is no obvious wetting or drying trend as the CO2 increases. The results suggest that changes to the land sea mask (relative to modern) in the models may be responsible for the simulated increases in precipitation to the north of Eocene Africa. There is an increase in precipitation over equatorial and West Africa and associated drying over northern Africa as CO2 rises. There are also important dynamical changes, with evidence that anticyclonic low‐level circulation is replaced by increased south‐westerly flow at high CO2 levels. Lastly, a model‐data comparison using newly‐compiled quantitative climate estimates from palaeobotanical proxy data suggests a marginally better fit with the reconstructions at lower levels of CO2.
Reichgelt, T., D. R. Greenwood, S. Steinig, J. G. Conran, D. K. Hutchinson, D. J. Lunt, L. J. Scriven, and J. Zhu. 2022. Plant Proxy Evidence for High Rainfall and Productivity in the Eocene of Australia. Paleoceanography and Paleoclimatology 37. https://doi.org/10.1029/2022pa004418
During the early to middle Eocene, a mid‐to‐high latitudinal position and enhanced hydrological cycle in Australia would have contributed to a wetter and “greener” Australian continent where today arid to semi‐arid climates dominate. Here, we revisit 12 southern Australian plant megafossil sites from the early to middle Eocene to generate temperature, precipitation and seasonality paleoclimate estimates, net primary productivity (NPP) and vegetation type, based on paleobotanical proxies and compare to early Eocene global climate models. Temperature reconstructions are uniformly subtropical (mean annual, summer, and winter mean temperatures 19–21 °C, 25–27 °C and 14–16 °C, respectively), indicating that southern Australia was ∼5 °C warmer than today, despite a >20° poleward shift from its modern geographic location. Precipitation was less homogeneous than temperature, with mean annual precipitation of ∼60 cm over inland sites and >100 cm over coastal sites. Precipitation may have been seasonal with the driest month receiving 2–7× less than mean monthly precipitation. Proxy‐model comparison is favorable with an 1680 ppm CO2 concentration. However, individual proxy reconstructions can disagree with models as well as with each other. In particular, seasonality reconstructions have systemic offsets. NPP estimates were higher than modern, implying a more homogenously “green” southern Australia in the early to middle Eocene, when this part of Australia was at 48–64 °S, and larger carbon fluxes to and from the Australian biosphere. The most similar modern vegetation type is modern‐day eastern Australian subtropical forest, although distance from coast and latitude may have led to vegetation heterogeneity.