Climatic change and extinction risk of two globally threatened Ethiopian endemic bird species

Modeling impacts of climate change on the geographic distribution and abundances of Tamarindus indica in Tigray region, Ethiopia

Tamarindus indica is a multipurpose dry land species in sub-Saharan that is traditionally used to build resilience into the farming system. The species is highly threatened and listed on the IUCN Red List. However, information on how climatic condition locally influences its ecological distribution is limited. This study investigates the current and future suitable habitat for the species in the Tigray region, in northern Ethiopia. A total of 220 species presence points and the number of T. indica within a 50 m × 50 m plot were collected. In addition, 19 bioclimatic variables, 3 topographic variables and soil data were used to model the impact of future climate conditions under two Representative Concentration Path Ways (RCP4.5 and RCP 8.5). MaxEnt-v-3.3.3 k, Diva-GIS-7.5, and GIS10.6 were used to model the current and future distribution. SPSSv-26 was also utilized to analyze the relationship between the species' abundance and environmental variables. Results showed that the environmental variables determining most for the distribution of T. indica were mean diurnal range (Bio2 (56.9%)); temperature seasonality (Bio4 (10.3%)) and temperature annual range (Bio7 (9.2%)). The model suggested that the current distribution of T. indica covers an area of 9209 km² (14.04%). This would have increased to 29,363 km² (44.78%) and 11,046 km² (16.85%) by 2070 under RCP4.5 and RCP8.5, respectively. Compared to the high-impact areas, new gains of suitable areas (net 25,081 km²) for the future distribution of the species were predicted in 2070-RCP4.5. Altitude, rainfall, temperature, silt contents of soils and soil pH have significant contributions (P-value<0.05) to the abundance of T. indica. However, altitude has a negative relationship with the abundance of T. indica. Additional studies to understand population trends and other threats are recommended.

Current Conservation Regimes and the Road to Laws on Assisted Migration

The negative impact of climate change on biodiversity will continue to escalate rapidly. While some species will naturally migrate to more suitable areas or adapt to the new climatic environmental conditions in different fashions, for others doing so may prove to be problematic or impossible. Against this backdrop, scientists and environmentalists have proposed implementing plans for Assisted Migration (AM)-meaning the translocation of plants and animals to areas outside their natural habitats to conserve their species under the new emerging climatic conditions. This article seeks to identify legal approaches towards AM considering not only possible benefits from using this tool but also a necessity to minimize related risks. With regard to its stated purpose, this article also compares legal and policy documents relevant to AM issues from the United States, Australia, and the European Union. In conclusion, we have found, and this article shows, that while existing legal and policy documents leave room for manoeuvreing in regard to climate-related translocations and even sometimes explicitly mention AM as a possible tool for conservation, there exists a need for the further development of concrete legal mechanisms and their balancing with the predominant ideas and goals brought about by the necessity to protect native biota.

New Evidence on the Linkage of Population Trends and Species Traits to Long-Term Niche Changes

Despite the assessment of long-term niche dynamics could provide crucial information for investigating species responses to environmental changes, it is a poorly investigated topic in ecology. Here, we present a case study of multi-species niche analysis for 71 common breeding birds in Northern Italy, exploring long-term niche changes from 1992 to 2017 and their relationship with both population trends and species traits. We (i) quantified the realized Grinnellian niche in the environmental space, (ii) compared variations in niche breadth and centroid, (iii) tested niche divergence and conservatism through equivalency and similarity tests, (iv) calculated niche temporal overlap, expansion and unfilling indices, and (v) investigated their association with both population changes and species traits. Results supported niche divergence (equivalency test) for 32% of species, although two-thirds were not supported by the similarity test. We detected a general tendency to adjust the niche centroids towards warmer thermal conditions. Increasing populations were positively correlated with niche expansion, while negatively correlated with niche overlap, albeit at the limit of the significance threshold. We found moderate evidence for a non-random association between niche changes and species traits, especially for body size, clutch size, number of broods per year, inhabited landscape type, and migration strategy. We encourage studies correlating long-term population trends and niche changes with species traits’ information and a specific focus on cause-effect relationship at both the single and multiple-species level.