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Purpose: Land use is a main driver of global biodiversity loss and its environmental relevance is widely recognized in research on life cycle assessment (LCA). The inherent spatial heterogeneity of biodiversity and its non-uniform response to land use requires a regionalized assessment, whereas many LCA applications with globally distributed value chains require a global scale. This paper presents a first approach to quantif land use impacts on biodiversity across different world regions and highlights uncertainties and research needs.

Methods: The study is based on the United Nations Environment Programme (UNEP)/Society of Environmental Toxicology and Chemistry (SETAC) land use assessment framework and focuses on occupation impacts, quantified as a biodiversity damage potential (BDP). Species richness of different land use types was compared to a (semi-)natural regional reference situation to calculate relative changes in species richness. Data on multiple species groups were derived from a global quantitative literature review and national biodiversity monitoring data from Switzerland. Differences across land use types, biogeographic regions (i.e., biomes), species groups and data source were statistically analyzed. For a data subset from the biome (sub-)tropical moist broadleaf forest, different species-based biodiversity indicators were calculated and the results compared.

Results and discussion: An overall negative land use impact was found for all analyzed land use types, but results varied considerably. Different land use impacts across biogeographic regions and taxonomic groups explained some of the variability. The choice of indicator also strongly influenced the results. Relative species richness was less sensitive to land use than indicators that considered similarity of species of the reference and the land use situation. Possible sources of uncertainty, such as choice of indicators and taxonomic groups, land use classification and regionalization are critically discussed and further improvements are suggested. Data on land use impacts were very unevenly distributed across the globe and considerable knowledge gaps on cause–effect chains remain.

Conclusions: The presented approach allows for a first rough quantification of land use impact on biodiversity in LCA on a global scale. As biodiversity is inherently heterogeneous and data availability is limited, uncertainty of the results is considerable. The presented characterization factors for BDP can approximate land use impacts on biodiversity in LCA studies that are not intended to directly support decision-making on land management practices. For such studies, more detailed and site-dependent assessments are required. To assess overall land use impacts, transformation impacts should additionally be quantified. Therefore, more accurate and regionalized data on regeneration times of ecosystems are needed.

de Baan, L., Alkemade, R., & Koellner, T. (2013). Land use impacts on biodiversity in LCA: A global approach. The International Journal of Life Cycle Assessment, 18(6), 1216–1230. https://doi.org/10.1007/s11367-012-0412-0

As a consequence of climate warming, species usually shift their distribution towards higher latitudes or altitudes. Yet, it is unclear how different taxonomic groups may respond to climate warming over larger altitudinal ranges. Here, we used data from the national biodiversity monitoring program of Switzerland, collected over an altitudinal range of 2500 m. Within the short period of eight years (2003–2010), we found significant shifts in communities of vascular plants, butterflies and birds. At low altitudes, communities of all species groups changed towards warm-dwelling species, corresponding to an average uphill shift of 8 m, 38 m and 42 m in plant, butterfly and bird communities, respectively. However, rates of community changes decreased with altitude in plants and butterflies, while bird communities changed towards warm-dwelling species at all altitudes. We found no decrease in community variation with respect to temperature niches of species, suggesting that climate warming has not led to more homogenous communities. The different community changes depending on altitude could not be explained by different changes of air temperatures, since during the 16 years between 1995 and 2010, summer temperatures in Switzerland rose by about 0.07uC per year at all altitudes. We discuss that land-use changes or increased disturbances may have prevented alpine plant and butterfly communities from changing towards warm-dwelling species. However, the findings are also consistent with the hypothesis that unlike birds, many alpine plant species in a warming climate could find suitable habitats within just a few metres, due to the highly varied surface of alpine landscapes. Our results may thus support the idea that for plants and butterflies and on a short temporal scale, alpine landscapes are safer places than lowlands in a warming world.

Roth, T., Plattner, M., & Amrhein, V. (2014). Plants, Birds and Butterflies: Short-Term Responses of Species Communities to Climate Warming Vary by Taxon and with Altitude. PLoS ONE, 9(1), e82490. https://doi.org/10.1371/journal.pone.0082490

Species ranges are shaped by both climatic factors and interactions with other species. The stress gradient hypothesis predicts that under physiologically stressful environmental conditions abiotic factors shape range edges while in less stressful environments negative biotic interactions are more important. Butterflies provide a suitable system to test this hypothesis since larvae of most species depend on biotic interactions with a specific set of host plants, which in turn can shape patterns of occurrence and distribution. Here we modelled the distribution of 92 butterfly and 136 host plant species with three different modelling algorithms, using distribution data from the Swiss biodiversity monitoring scheme at a 1 km² spatial resolution. By comparing the ensemble prediction for each butterfly species and the corresponding host plant(s), we assessed potential constraints imposed by host plant availability on distribution of butterflies at their distributional limits along the main environmental gradient, which closely parallels an elevational gradient. Our results indicate that host limitation does not play a role at the lower limit. At the upper limit 50% of butterfly species have a higher elevational limit than their primary host plant, and 33% have upper elevational limits that exceed the limits of both primary and secondary hosts. We conclude that host plant limitation was not relevant to butterfly distributional limits in less stressful environments and that distributions are more likely limited by climate, land use or antagonistic biotic interactions. Obligatory dependency of butterflies on their host plants, however, seems to represent an important limiting factor for the distribution of some species towards the cold, upper end of the environmental gradient, suggesting that biotic factors can shape ranges in stressful environments. Thus, predictions by the stress gradient hypothesis were not always applicable.

Hanspach, J., Schweiger, O., Kühn, I., Plattner, M., Pearman, P. B., Zimmermann, N. E., & Settele, J. (2014). Host plant availability potentially limits butterfly distributions under cold environmental conditions. Ecography, 37(3), 301–308. https://doi.org/10.1111/j.1600-0587.2013.00195.x

Purpose

Halting the loss of biodiversity while providing food security for a growing and prospering world population is a challenge. One possible solution to this dilemma is organic agriculture, which is expected to enhance biodiversity on the farmland. However, organic products often require larger areas. This study demonstrates how we can quantify and compare the direct land use impacts on biodiversity of organic and conventional food products such as milk.

Material and methods

This study assessed direct land use impacts of 1 l of milk leaving the farm gate. Inventory data on land occupation were extracted from a life cycle assessment study of 15 farms in southern Sweden. Direct land use change data were derived from the FAO statistical database. Spatially differentiated characterization factors of occupation (CF_Occ) and transformation (CF_Trans) were calculated based on the relative difference of plant species richness on agricultural land compared to a (semi) natural regional reference. Data on plant species richness and regeneration times of ecosystems (for calculating transformation impacts) were derived from a literature review. To account for differences in biodiversity value between regions, a weighting system based on absolute species richness, vulnerability and irreplaceability was applied.

Results and discussion

Organic milk had a lower direct land use impact than conventional milk, although it required about double the area. Occupation impacts dominated the results and were much smaller for organic than conventional milk, as CF_Occ of organic land uses were considerably smaller. For transformation impacts, differences between the two farming practices were even more pronounced. The highest impacts were caused by soymeal in concentrate feeds (conventional milk) due to large-scale deforestation in its country of cultivation (i.e. Brazil and Argentina). However, lack of reliable data posed a challenge in the assessment of transformation impacts. Overall, results were highly sensitive to differences in land occupation area between farms, the CF_Occ and assumptions concerning transformed area. Sensitivity and robustness of results were tested and are discussed.

Conclusions

Although organic milk required about twice as much land as conventional, it still had lower direct land use impacts on biodiversity. This highlights the importance of assessing land use impacts not only based on area but also considering the actual impacts on biodiversity. The presented approach allows to quantify and compare hot- and coldspots in the agricultural stage of milk production and could potentially also be applied to other agricultural products. However, more research is needed to allow quantification of indirect land use impacts.

Mueller, C., de Baan, L., & Koellner, T. (2014). Comparing direct land use impacts on biodiversity of conventional and organic milk—Based on a Swedish case study. The International Journal of Life Cycle Assessment, 19(1), 52–68. https://doi.org/10.1007/s11367-013-0638-5