Abstract Understanding the influence of environmental covariates on plants’ distribution is critical, especially for aquatic plant species. Climate change is likely to alter the distribution of aquatic species. However, knowledge of this change on the burden of aquatic macroorganisms is often fraught with difficulty. Ottelia Pers., a model genus for studying the evolution of the aquatic family Hydrocharitaceae, is mainly distributed in slow-flowing creeks, rivers or lakes throughout the world’s pantropical areas. Due to recent rapid climate changes, the natural Ottelia populations have declined significantly. In the present study, we use maximum entropy (MaxEnt) to explore the environmental drivers of seven Ottelia species distribution in African freshwater bodies. The models use known background points to determine how environmental covariates vary spatially and produce continental maps of these species’ distribution. We also estimate the possible influences of the optimistic and extreme pessimistic Intergovernmental Panel on Climate Change (IPCC) pathway scenarios and identify high suitability areas under these scenarios. Model performances were statistically significant than random expectations with Area Under Curve (AUC) values above 0.831, indicating the good performance of the models. We observe that our studied Ottelia species had distinct spatial patterns influenced by climate variations (e.g. Bio9- mean temperature of driest quarter, Bio12- annual precipitation, and Bio14- Precipitation of the driest month). While there is a lack of accord in defining the limiting factors for the distribution of the seven species, it is clear that water-temperature conditions have promising effects when kept within optimal ranges. Niche overlap analyses showed that most Ottelia species have similar but not equivalent climatic niches. In addition, considering the expected warming in the future, the persistence and survival of the Ottelia species in Africa could be compromised. The present findings provide a theoretical basis for the distribution of various Ottelia species in Africa.
Climate change poses a serious long-term threat to biodiversity. To effectively reduce biodiversity loss, conservationists need to have a thorough understanding of the preferred habitats of species and the variables that affect their distribution. Therefore, predicting the impact of climate change on species-appropriate habitats may help mitigate the potential threats to biodiversity distribution.
Globally, endemic species and natural habitats have been significantly impacted by climate change, and further considerable impacts are predicted. Therefore, understanding how endemic species are impacted by climate change can aid in advancing the necessary conservation initiatives. The use of niche modeling is becoming a popular topic in biological conservation to forecast changes in species distributions under various climate change scenarios. This study used the Australian Community Climate and Earth System Simulator version 1 (ACCESS-CM2) general circulation model of coupled model intercomparison project phase 6 (CMIP6) to model the current distribution of suitable habitat for the four threatened Annonaceae species endemic to East Africa (EA), to determine the impact of climate change on their suitable habitat in the years 2050 (average for 2041-2060) and 2070 (average for 2061-2080). Two shared socio-economic pathways (SSPs) SSP370 and SSP585 were used to project the contraction and expansion of suitable habitats for Uvariodendron kirkii, Uvaria kirkii, Uvariodendron dzomboense and Asteranthe asterias endemic to Kenya and Tanzania in EA. The current distribution for all four species is highly influenced by precipitation, temperature, and environmental factors (population, potential evapotranspiration, and aridity index). Although the loss of the original suitable habitat is anticipated to be significant, appropriate habitat expansion and contraction are projections for all species. More than 70% and 40% of the original habitats of Uvariodendron dzombense and Uvariodendron kirkii are predicted to be destroyed by climate change, respectively. Based on our research, we suggest that areas that are expected to shrink owing to climate change be classified as important protection zones for the preservation of Annonaceae species.
Abstract Global climate change is among the major anthropogenic factors impacting species distribution, with significant conservation implications. Yet, little is known about the effects of climate warming on the distributional shifts of East Asian species. In the current study, we used the maximum entropy model (MaxEnt) to determine present and possible future habitats for five Meehania species occurring in the East Asian region. Our objectives were to evaluate how climate change would influence the species' habitat under current and future climate scenarios (Representative Concentration Pathways 4.5 and 8.5). The mean area under the curve (AUC) ranged between 0.896 and 0.973, while the TSS values for all species varied between 0.811 and 0.891. The modelled current habitat of the species corresponded with the recorded distribution localities, confirming the model's robustness. Analysis of variable contribution demonstrated that the distribution of the species had differential environmental requirements; however, isothermality, precipitation of driest month, and elevation variables were among the main influential variables. Based on present climatic conditions, the projected habitat suitability maps showed a total of 662,846.0 to 2,039,180.1 km2 as suitable regions for the distribution of Meehania species. In addition, there was a substantial loss in habitat range under future climatic scenarios for all the species. While the East Asian region is rich in biodiversity, more attention should be given to its management conservation. The current findings provide a scientific foundation for the conservation of Meehania and other species' habitats in the region.
The International Panel on Climate Change (IPCC) projects a global temperature rise of 4.3 ± 0.7 °C by 2100 and an extinction of 8.5% in one out of every six species. Australia's aquatic ecosystem is no exception; habitat loss, fragmentation, and loss of biodiversity are being experienced. As the center for
Predicting the responses of threatened tropical plant species to global climate change has been considered to be critical for assessing changes in species distribution and evaluating their conservation status. In reflecting on the vast species richness, East Africa has long been recognised as a hotspot of biodiversity, but very little is known about the vulnerability of the endemic plant diversity to anthropogenic introduced climate changes. This study evaluated the potential impacts of global climate change on plant species ranges in coastal East Africa by predicting the extent and direction of projected changes in climatic suitability. Specifically, we employed species distribution modelling in MaxEnt to identify species experiencing the highest threat of range declines. To do so, we evaluated climatic suitability for eleven legume species using one global climate model and two greenhouse gas emissions scenarios for present and future climates. The findings indicated that the mean AUC and TSS values of the focal taxa ranged from 0.818 to 0.992 and from 0.780 to 0.851, respectively, indicating that the MaxEnt model's prediction accuracy was good or exceptional. Occupancy and abundance of nine species were positively associated with low elevations, high relative humidity, and warmer temperatures in the coastal regions. Regardless of species, precipitation of the warmest quarter and mean temperature of the wettest quarter exhibited a minor impact on the distribution. Furthermore, the probable distribution regions of these species ranged from 77,270 km2 to 282,297 km2. To our knowledge, this study is the first to appraise the distribution of threatened species within Fabaceae in coastal East Africa. The current findings provide a critical assessment framework for the conservation and management of Fabaceae in the region.
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