• Energy Research

Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation. This work was funded by the MAVA Foundation trough the MAVA Safe Flyways Energy project, specifically the M7 Birds – Reducing mortality of migratory birds and vultures in the Mediterranean 2016–2022.

Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation. This work was funded by the MAVA Foundation trough the MAVA Safe Flyways Energy project, specifically the M7 Birds – Reducing mortality of migratory birds and vultures in the Mediterranean 2016–2022.

Saltwater intrusion can dramatically transform coastal ecosystems, changing vegetation and impacting wildlife and human communities who rely on these natural resources. This phenomenon is difficult to measure over large and remote areas but can be inferred from changes in the distribution of salt-tolerant vegetation, such as mangroves, observable from satellite imagery. The northern coast of Brazil has the largest continuous mangrove forest in the world and very low human occupation. Even so, saltwater intrusion and changes to the coastline have been reported in this region, with potential consequences for mangrove carbon storage and for local livelihoods, but this has not been quantified due to the remoteness of the area. This study measured changes in mangrove distribution along the Northern Brazil coast in the state of Amapá, covering ca. 15,000 km2, over the last 38 years using Landsat satellite imagery. We found that mangrove area in this region is highly dynamic, with significant gains and losses occurring over the study period, but with an overall net gain of 157 km2. Mangroves have been systematically expanding inland and this growth has accelerated close to the shoreline and at the head of tidal channels in the last two decades, indicating rapid and large-scale saltwater intrusion in this region. This phenomenon is likely driven by sea level rise, which also accelerated in this region in recent decades, but anthropogenic impacts such as buffalo grazing may also play an important role.

Saltwater intrusion can dramatically transform coastal ecosystems, changing vegetation and impacting wildlife and human communities who rely on these natural resources. This phenomenon is difficult to measure over large and remote areas but can be inferred from changes in the distribution of salt-tolerant vegetation, such as mangroves, observable from satellite imagery. The northern coast of Brazil has the largest continuous mangrove forest in the world and very low human occupation. Even so, saltwater intrusion and changes to the coastline have been reported in this region, with potential consequences for mangrove carbon storage and for local livelihoods, but this has not been quantified due to the remoteness of the area. This study measured changes in mangrove distribution along the Northern Brazil coast in the state of Amapá, covering ca. 15,000 km2, over the last 38 years using Landsat satellite imagery. We found that mangrove area in this region is highly dynamic, with significant gains and losses occurring over the study period, but with an overall net gain of 157 km2. Mangroves have been systematically expanding inland and this growth has accelerated close to the shoreline and at the head of tidal channels in the last two decades, indicating rapid and large-scale saltwater intrusion in this region. This phenomenon is likely driven by sea level rise, which also accelerated in this region in recent decades, but anthropogenic impacts such as buffalo grazing may also play an important role.

AbstractPartial migration—wherein migratory and non‐migratory individuals exist within the same population—represents a behavioural dimorphism; for it to persist over time, both strategies should yield equal individual fitness. This balance may be maintained through trade‐offs where migrants gain survival benefits by avoiding unfavourable conditions, while residents gain breeding benefits from early access to resources.There has been little overarching quantitative analysis of the evidence for this fitness balance. As migrants—especially long‐distance migrants—may be particularly vulnerable to environmental change, it is possible that recent anthropogenic impacts could drive shifts in fitness balances within these populations.We tested these predictions using a multi‐taxa meta‐analysis. Of 2,939 reviewed studies, 23 contained suitable information for meta‐analysis, yielding 129 effect sizes.Of these, 73% (n = 94) reported higher resident fitness, 22% (n = 28) reported higher migrant fitness, and 5% (n = 7) reported equal fitness. Once weighted for precision, we found balanced fitness benefits across the entire dataset, but a consistently higher fitness of residents over migrants in birds and herpetofauna (the best‐sampled groups). Residency benefits were generally associated with survival, not breeding success, and increased with the number of years of data over which effect sizes were calculated, suggesting deviations from fitness parity are not due to sampling artefacts.A pervasive survival benefit to residency documented in recent literature could indicate that increased exposure to threats associated with anthropogenic change faced by migrating individuals may be shifting the relative fitness balance between strategies.