The effects of climate and land use on British bumblebees:Findings from a decade of citizen-science observations

Bumblebees are important pollinators but are suffering from population declines due to land use intensification and climate change. In-depth knowledge of species' relationships with different land use and climate variables is invaluable to guide conservation efforts, as well as enable predictions to be made about the impacts of future changes in these variables. Here we use 10 years of bumblebee abundance data from the UK, collected by citizen scientists as part of the BeeWalk scheme, to investigate associations between 14 bumblebee species and various land use, habitat and climate variables. National-scale land cover and climate data were complemented with observer-collected habitat data. Bumblebee presence and abundance showed strong relationships with environmental variables. However, interspecific variation was far stronger than commonalities, which suggests that targeted conservation work is required to effectively safeguard particular species. Within species, we found evidence of different habitat associations between reproductive and worker castes. The results also showed that wetland and riparian habitats had consistently positive associations with a number of species, while semi-natural, arable and urban areas had strongly species-specific associations. Synthesis and applications. This study reveals strong effects of specific habitats occurring within broad land cover types on the presence and abundance of bumblebees, with several distinct habitats having importance for different species and castes. Consequently, conservation efforts need to be carefully tailored to particular species. Nevertheless, reversing the loss of semi-natural areas such as wetlands may be the single most generally effective action for bumblebee conservation while improving habitats in urban and arable areas could benefit particular (rare) species. Our results also suggest that the combination of long-term, detailed monitoring data of both species and habitats, here collected by citizen scientists, with remotely sensed landcover and climate data is essential to extend knowledge of species' habitat requirements and to support future research and conservation.</p

The effects of climate and land use on British bumblebees: Findings from a decade of citizen‐science observations

Bumblebees are important pollinators but are suffering from population declines due to land use intensification and climate change. In-depth knowledge of species' relationships with different land use and climate variables is invaluable to guide conservation efforts, as well as enable predictions to be made about the impacts of future changes in these variables. Here we use 10 years of bumblebee abundance data from the UK, collected by citizen scientists as part of the BeeWalk scheme, to investigate associations between 14 bumblebee species and various land use, habitat and climate variables. National-scale land cover and climate data were complemented with observer-collected habitat data. Bumblebee presence and abundance showed strong relationships with environmental variables. However, interspecific variation was far stronger than commonalities, which suggests that targeted conservation work is required to effectively safeguard particular species. Within species, we found evidence of different habitat associations between reproductive and worker castes. The results also showed that wetland and riparian habitats had consistently positive associations with a number of species, while semi-natural, arable and urban areas had strongly species-specific associations. Synthesis and applications. This study reveals strong effects of specific habitats occurring within broad land cover types on the presence and abundance of bumblebees, with several distinct habitats having importance for different species and castes. Consequently, conservation efforts need to be carefully tailored to particular species. Nevertheless, reversing the loss of semi-natural areas such as wetlands may be the single most generally effective action for bumblebee conservation while improving habitats in urban and arable areas could benefit particular (rare) species. Our results also suggest that the combination of long-term, detailed monitoring data of both species and habitats, here collected by citizen scientists, with remotely sensed landcover and climate data is essential to extend knowledge of species' habitat requirements and to support future research and conservation.</p

Effects of climate-induced changes in isoprene emissions after the eruption of Mount Pinatubo

In the 1990s the rates of increase of greenhouse gas concentrations, most notably of methane, were observed to change, for reasons that have yet to be fully determined. This period included the eruption of Mt. Pinatubo and an El Nino warm event, both of which affect biogeochemical processes, by changes in temperature, precipitation and radiation. We examine the impact of these changes in climate on global isoprene emissions and the effect these climate dependent emissions have on the hydroxy radical, OH, the dominant sink for methane. We model a reduction of isoprene emissions in the early 1990s, with a maximum decrease of 40 Tg(C)/yr in late 1992 and early 1993, a change of 9%. This reduction is caused by the cooler, drier conditions following the eruption of Mt. Pinatubo. Isoprene emissions are reduced both directly, by changes in temperature and a soil moisture dependent suppression factor, and indirectly, through reductions in the total biomass. The reduction in isoprene emissions causes increases of tropospheric OH which lead to an increased sink for methane of up to 5 Tg(CH4)/year, comparable to estimated source changes over the time period studied. There remain many uncertainties in the emission and oxidation of isoprene which may affect the exact size of this effect, but its magnitude is large enough that it should remain important

Making protected areas effective for biodiversity, climate and food

The spatial extent of marine and terrestrial protected areas (PAs) was among the most intensely debated issues prior to the decision about the post-2020 Global Biodiversity Framework (GBF) of the Convention on Biological Diversity. Positive impacts of PAs on habitats, species diversity and abundance are well documented. Yet, biodiversity loss continues unabated despite efforts to protect 17% of land and 10% of the oceans by 2020. This casts doubt on whether extending PAs to 30%, the agreed target in the Kunming-Montreal GBF, will indeed achieve meaningful biodiversity benefits. Critically, the focus on area coverage obscures the importance of PA effectiveness and overlooks concerns about the impact of PAs on other sustainability objectives. We propose a simple means of assessing and visualising the complex relationships between PA area coverage and effectiveness and their effects on biodiversity conservation, nature-based climate mitigation and food production. Our analysis illustrates how achieving a 30% PA global target could be beneficial for biodiversity and climate. It also highlights important caveats: (i) achieving lofty area coverage objectives alone will be of little benefit without concomitant improvements in effectiveness, (ii) trade-offs with food production particularly for high levels of coverage and effectiveness are likely and (iii) important differences in terrestrial and marine systems need to be recognized when setting and implementing PA targets. The CBD's call for a significant increase in PA will need to be accompanied by clear PA effectiveness goals to reduce and revert dangerous anthropogenic impacts on socio-ecological systems and biodiversity

Modelling population structure in the context of urban land use change in Europe

Population structure and dynamics are important drivers of land use. In this article, we present the methods and outcomes of integrating population projections across multiple spatial scales with an urban growth model. By linking shared socioeconomic pathway (SSP)-specific national population projections to present-day population distributions at a sub-national scale, we describe a downscaling approach that provides input into a regional urban growth (RUG) model for Europe. The allocation of population acts as a key driver for residential urban demand especially in the SSP5-based scenario, and therefore regional (sub-national) urban growth. Sub-national population trends can deviate strongly from national averages stemming from current population age structures: this creates different urban land use patterns and demand for artificial surfaces. We see strong population dependence in the regional development of urban areas across Europe, and the effects caused by age structure and sub-national population dynamics