What Is the Impact of Accidentally Transporting Terrestrial Alien Species? A New Life Cycle Impact Assessment Model.

Alien species form one of the main threats to global biodiversity. Although Life Cycle Assessment attempts to holistically assess environmental impacts of products and services across value chains, ecological impacts of the introduction of alien species are so far not assessed in Life Cycle Impact Assessment. Here, we developed country-to-country-specific characterization factors, expressed as the time-integrated potentially disappeared fraction (PDF; regional and global) of native terrestrial species due to alien species introductions per unit of goods transported [kg] between two countries. The characterization factors were generated by analyzing global data on first records of alien species, native species distributions, and their threat status, as well as bilateral trade partnerships from 1870-2019. The resulting characterization factors vary over several orders of magnitude, indicating that impact greatly varies per transportation route and trading partner. We showcase the applicability and relevance of the characterization factors for transporting 1 metric ton of freight to France from China, South Africa, and Madagascar. The results suggest that the introduction of alien species can be more damaging for terrestrial biodiversity as climate change impacts during the international transport of commodities.

Land use diversification may mitigate on-site land use impacts on mammal populations and assemblages.

Land use is a major cause of biodiversity decline worldwide. Agricultural and forestry diversification measures, such as the inclusion of natural elements or diversified crop types, may reduce impacts on biodiversity. However, the extent to which such measures may compensate for the negative impacts of land use remains unknown. To fill that gap, we synthesised data from 99 studies that recorded mammal populations or assemblages in natural reference sites and in cropland and forest plantations, with or without diversification measures. We quantified the responses to diversification measures based on individual species abundance, species richness and assemblage intactness as quantified by the mean species abundance indicator. In cropland with natural elements, mammal species abundance and richness were, on average, similar to natural conditions, while in cropland without natural elements they were reduced by 28% and 34%, respectively. We found that mammal species richness was comparable between diversified forest plantations and natural reference sites, and 32% lower in plantations without natural elements. In both cropland and plantations, assemblage intactness was reduced compared with natural reference conditions, but the reduction was smaller if diversification measures were in place. In addition, we found that responses to land use were modified by species traits and environmental context. While habitat specialist populations were reduced in cropland without diversification and in forest plantations, habitat generalists benefited. Furthermore, assemblages were impacted more by land use in tropical regions and landscapes containing a larger share of (semi)natural habitat compared with temperate regions and more converted landscapes. Given that mammal assemblage intactness is reduced also when diversification measures are in place, special attention should be directed to species that suffer from land use impacts. That said, our results suggest potential for reconciling land use and mammal conservation, provided that the diversification measures do not compromise yield.

Biodiversity Impact Assessment Considering Land Use Intensities and Fragmentation.

Land use is a major threat to terrestrial biodiversity. Life cycle assessment is a tool that can assess such threats and thereby support environmental decision-making. Within the Global Guidance for Life Cycle Impact Assessment (GLAM) project, the Life Cycle Initiative hosted by UN Environment aims to create a life cycle impact assessment method across multiple impact categories, including land use impacts on ecosystem quality represented by regional and global species richness. A working group of the GLAM project focused on such land use impacts and developed new characterization factors to combine the strengths of two separate recent advancements in the field: the consideration of land use intensities and land fragmentation. The data sets to parametrize the underlying model are also updated from previous models. The new characterization factors cover five species groups (plants, amphibians, birds, mammals, and reptiles) and five broad land use types (cropland, pasture, plantations, managed forests, and urban land) at three intensity levels (minimal, light, and intense). They are available at the level of terrestrial ecoregions and countries. This paper documents the development of the characterization factors, provides practical guidance for their use, and critically assesses the strengths and remaining shortcomings.

Potential Consequences of Regional Species Loss for Global Species Richness: A Quantitative Approach for Estimating Global Extinction Probabilities.

Because the biosphere is highly heterogeneous, species diversity impacts are typically assessed at local or regional scales. Because regional species richness impact metrics refer to different species compositions, they cannot be easily compared or aggregated to global impacts. Translating regional species richness impacts into global impacts allows for comparisons between impacts and facilitates the estimation of global species extinctions. This requires a conversion (or weighting) factor that takes into account the characteristics of regionally specific species compositions. We developed a methodology for deriving such conversion factors based on species' habitat ranges, International Union for Conservation of Nature threat levels, and species richness. We call these conversion factors global extinction probabilities (GEPs) of the reference location or region. The proposed methodology allows for the calculation of GEPs for any spatial unit and species group for which data on spatial distribution are available and can be implemented in methodologies like life cycle impact assessment. Furthermore, the GEPs can be used for the identification of conservation hot spots. The results of the proposed GEPs (for various taxonomic groups) show that the risk that regional species loss may result in global species extinctions significantly differs per region and informs where irreversible biodiversity impacts are more likely to occur.

The potential of emerging bio-based products to reduce environmental impacts.

The current debate on the sustainability of bio-based products questions the environmental benefits of replacing fossil- by bio-resources. Here, we analyze the environmental trade-offs of 98 emerging bio-based materials compared to their fossil counterparts, reported in 130 studies. Although greenhouse gas life cycle emissions for emerging bio-based products are on average 45% lower (-52 to -37%; 95% confidence interval), we found a large variation between individual bio-based products with none of them reaching net-zero emissions. Grouped in product categories, reductions in greenhouse gas emissions ranged from 19% (-52 to 35%) for bioadhesives to 73% (-84 to -54%) for biorefinery products. In terms of other environmental impacts, we found evidence for an increase in eutrophication (369%; 163 to 737%), indicating that environmental trade-offs should not be overlooked. Our findings imply that the environmental sustainability of bio-based products should be evaluated on an individual product basis and that more radical product developments are required to reach climate-neutral targets.

Extracellular vesicle-associated cholesterol supports the regenerative functions of macrophages in the brain.

Macrophages play major roles in the pathophysiology of various neurological disorders, being involved in seemingly opposing processes such as lesion progression and resolution. Yet, the molecular mechanisms that drive their harmful and benign effector functions remain poorly understood. Here, we demonstrate that extracellular vesicles (EVs) secreted by repair-associated macrophages (RAMs) enhance remyelination ex vivo and in vivo by promoting the differentiation of oligodendrocyte precursor cells (OPCs). Guided by lipidomic analysis and applying cholesterol depletion and enrichment strategies, we find that EVs released by RAMs show markedly elevated cholesterol levels and that cholesterol abundance controls their reparative impact on OPC maturation and remyelination. Mechanistically, EV-associated cholesterol was found to promote OPC differentiation predominantly through direct membrane fusion. Collectively, our findings highlight that EVs are essential for cholesterol trafficking in the brain and that changes in cholesterol abundance support the reparative impact of EVs released by macrophages in the brain, potentially having broad implications for therapeutic strategies aimed at promoting repair in neurodegenerative disorders.

Considering habitat conversion and fragmentation in characterisation factors for land-use impacts on vertebrate species richness.

Human land use is one of the primary threats to terrestrial species richness and is considered a priority for meeting global sustainability and biodiversity targets. Decision-support tools, such as life cycle assessment (LCA), are widely used for developing strategies to achieve such objectives. Currently available life cycle impact assessment (LCIA) methods apply the countryside species-area relationship (c-SAR) to quantify habitat conversion impacts on species richness. However, additional effects of habitat fragmentation are yet ignored in these assessments. We use the species-habitat relationship (SHR), an adaptation of the c-SAR that considers both habitat conversion and fragmentation effects, to develop a new set of land-use characterisation factors for 702 terrestrial ecoregions (in 238 countries), four land-use types (urban, cropland, pasture, and forestry), and four taxonomic groups (amphibians, birds, mammals, and reptiles; plus the aggregate of these vertebrate groups). The SHR generally predicts higher per-area impacts of land-use than the impacts estimated by the c-SAR (a median relative difference of +9%), indicating that land-use impacts may be systematically underestimated when ignoring fragmentation effects. Whereas per-area impacts of land-use on regional species richness are highest in temperate regions, reflecting the diminished extent of natural habitat, per-area impacts of land-use on global species richness are highest in the subtropics, reflecting the importance of tropical regions and islands to global vertebrate species diversity. The large variety in magnitude of land-use impacts across the world's regions emphasizes the importance of regionalised assessments. The set of characterisation factors proposed here can be readily used in environmental decision-making.

Global characterization factors for terrestrial biodiversity impacts of future land inundation in Life Cycle Assessment.

Life Cycle Assessment (LCA) is a tool for analyzing and comparing environmental impacts of products throughout their life cycles, facilitating shifts towards more environmentally friendly products. However, LCA does currently not address terrestrial biodiversity impacts related to the conversion of terrestrial habitat into aquatic habitat. This conversion can occur because of sea level rise, establishment of new land-based aquaculture, as well as reservoir expansion or creation. Here, we focus on land occupation and terrestrial biodiversity impacts, while transformation impacts, and habitat gain for aquatic species were beyond the scope of the study. To be able to estimate the regional and global terrestrial biodiversity impacts of future land occupation from terrestrial to aquatic habitat in LCA, we developed new characterization factors (CFs) for 781 terrestrial ecoregions, 5 land cover/use types, and 4 taxonomic groups. The basis for the development of the proposed CFs is the model concept of the currently recommended method for quantifying land use impacts on biodiversity in LCA by the Life Cycle Initiative hosted by United Nations Environmental Program. The global CFs vary between 7.44 E-20 PDF/m2 and 6.25 E-09 PDF/m2, showing that a highly variable terrestrial biodiversity impact of land inundation between land cover/use types, taxonomic groups and ecoregions exists.