Featured Journal Content
19 June 2020 Vol 368, Issue 6497
Landscape-scale forest loss as a catalyst of population and biodiversity change
By Gergana N. Daskalova, Isla H. Myers-Smith, Anne D. Bjorkman, Shane A. Blowes, Sarah R. Supp, Anne E. Magurran, Maria Dornelas
Science19 Jun 2020 : 1341-1347 Restricted Access
Declines in forest cover amplify both gains and losses in plant and animal population abundance and diversity over time.
Land-use change and forest biodiversity
Land-use change by humans, particularly forest loss, is influencing Earth’s biodiversity through time. To assess the influence of forest loss on population and biodiversity change, Daskalova et al. integrated data from more than 6000 time series of species’ abundance, richness, and composition in ecological assemblages around the world. Forest loss leads to both positive and negative responses of populations and biodiversity, and the temporal lags in population and biodiversity change after forest loss can extend up to half a century. Land-use change precipitates divergent population and biodiversity change. This analysis has consequences for projections of human impact, ongoing conservation, and assessments of biodiversity change.
Global biodiversity assessments have highlighted land-use change as a key driver of biodiversity change. However, there is little empirical evidence of how habitat transformations such as forest loss and gain are reshaping biodiversity over time. We quantified how change in forest cover has influenced temporal shifts in populations and ecological assemblages from 6090 globally distributed time series across six taxonomic groups. We found that local-scale increases and decreases in abundance, species richness, and temporal species replacement (turnover) were intensified by as much as 48% after forest loss. Temporal lags in population- and assemblage-level shifts after forest loss extended up to 50 years and increased with species’ generation time. Our findings that forest loss catalyzes population and biodiversity change emphasize the complex biotic consequences of land-use change.
Climate-driven risks to the climate mitigation potential of forests
By William R. L. Anderegg, Anna T. Trugman, Grayson Badgley, Christa M. Anderson, Ann Bartuska, Philippe Ciais, Danny Cullenward, Christopher B. Field, Jeremy Freeman, Scott J. Goetz, Jeffrey A. Hicke, Deborah Huntzinger, Robert B. Jackson, John Nickerson, Stephen Pacala, James T. Randerson
Science19 Jun 2020
Risks to mitigation potential of forests
Much recent attention has focused on the potential of trees and forests to mitigate ongoing climate change by acting as sinks for carbon. Anderegg et al. review the growing evidence that forests’ climate mitigation potential is increasingly at risk from a range of adversities that limit forest growth and health. These include physical factors such as drought and fire and biotic factors, including the depredations of insect herbivores and fungal pathogens. Full assessment and quantification of these risks, which themselves are influenced by climate, is key to achieving science-based policy outcomes for effective land and forest management.
Forests have considerable potential to help mitigate human-caused climate change and provide society with a broad range of cobenefits. Local, national, and international efforts have developed policies and economic incentives to protect and enhance forest carbon sinks—ranging from the Bonn Challenge to restore deforested areas to the development of forest carbon offset projects around the world. However, these policies do not always account for important ecological and climate-related risks and limits to forest stability (i.e., permanence). Widespread climate-induced forest die-off has been observed in forests globally and creates a dangerous carbon cycle feedback, both by releasing large amounts of carbon stored in forest ecosystems to the atmosphere and by reducing the size of the future forest carbon sink. Climate-driven risks may fundamentally compromise forest carbon stocks and sinks in the 21st century. Understanding and quantifying climate-driven risks to forest stability are crucial components needed to forecast the integrity of forest carbon sinks and the extent to which they can contribute toward the Paris Agreement goal to limit warming well below 2°C. Thus, rigorous scientific assessment of the risks and limitations to widespread deployment of forests as natural climate solutions is urgently needed…