Monday, August 3, 2020

August 2020 science article summary

Passion flower


I'm on vacation in the woods with no phone or internet access, but sending this via the magic of delayed delivery. Getting away from people doesn't have as much allure these days, but getting away from the news does!

I've been looking at a lot of papers lately around big global conservation goals (which should be interesting to most), as well as more technical papers around metrics and indicators (with less broad appeal). There's also a very cool paper just out in Science on plastic pollution (and how to reduce it), and a paper from Chile finding that subsidies to plant trees had the side-effect of increasing forest cover loss (while dramatically expanding plantations).

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Lau et al. 2020 is an important analysis of the scope of plastic pollution and how to reduce it. The paper found 29 Mt of plastic enters the environment each year (as of 2016, with ~1/3 going to the ocean), and plastic pollution to the ocean could triple by 2040 without immediate and sustained action. Current commitments by government and industry will only reduce the amount of plastic pollution to the ocean by 7% by 2040, but the report lays out eight measures that could reduce it by 80% by 2040 instead. There is a far better (and more thorough) summary of the paper at

Bhola et al. 2020 sums up four different philosophies or perspectives for setting global conservation goals. 1) extending Aichi biodiversity target #11 (protecting & managing 17% of land and inland water, plus 10% coastal and marine, while considering biodiversity, equity, ecosystem services, and connectivity) to 2030 and ensuring the qualitative piece is achieved. 2) Big area-based goals like 'half earth' or protecting 30% of the earth by 2030 (still ensuring that the right places get protected). 3) ‘New conservation’ (broadening the tent for conservation via ecosystem services, ecotourism, and the private sector). 4) ‘Whole earth’ conservation which attacks root causes of habitat loss like inequality and economic growth (while arguing against separating people from nature). It's a quick read but start w/ Table 1 for a summary of the four perspectives, and Figure 1 which shows how the choice of goal (in this case, biodiversity vs. ecosystem service production) affects which areas you’d want to protect. 

Allan et al 2019 is a preprint (not peer reviewed yet) but has some weight behind it via the author list. Their approach was to start with the union of all Key Biodiversity Areas (KBAs), all wilderness areas, and all current protected areas, then see how much extra land was needed to capture enough of the range of ~29k spp. to enable their persistence. Their answer is that we need 44% of the land on earth for conservation. Note that they do NOT say 44% should be legally protected, but rather than it should be managed via a range of strategies. While there's no one single "right answer" to how much land we need (since it depends on your values, and on the assumptions and data you use), this is one of many defensible ways to approach this.

Gownaris et al. 2019 reviews 10 global analyses (from the UN and NGOs) of which parts of the ocean are the most important for conservation (see Table 1 for a list of criteria used to define importance in each). See Figure 2 for the key results; they found 49% of the ocean was both unprotected and identified as important by at least one analysis. 45% of the ocean wasn't listed as important by any analysis, 40% was important in only 1 analysis, 14% was important in 2-4 analyses (of which 88% was unprotected: not covered by an MPA of any level of protection), and <1% was important in 5 or more (of which 5% was unprotected). Virtually all important area was in blocks larger than 100 km2, and 97% of the area listed by at least two analyses was within exclusive economic zones (EEZs). They note that they couldn't get at efficacy or strength of protection, but this is a useful high level overview of some likely candidates for both new protection and improved management and/or protection in existing MPAs.

Fraser et al. 2006 discusses three case studies where communities were involved in choosing sustainability indicators (both environmental and human), along with external experts. Each case talks about the process they used to choose indicators, and shares example indicators. They found participatory indicator development is complex and slow (sometimes preventing use by policy makers), but empowers communities. Table 1 has some human wellbeing indicators (including some flagged as unmeasurable but representing important gaps in knowledge). Table 3 shows environmental indicators seen as providing early warning of pastoral degradation. Table 4 has a broad suite of categories of metrics (w/o detail on how to measure them) for both human and environmental issues.

Tucker et al. 2017 is an overview of metrics of phylogenetic diversity (which they break into richness, divergence / relatedness, and regularity). There is a highly technical review of 70 specific metrics, followed by a note on other key considerations like abundance, how to weight rare vs common species, and how to deal with correlations related to species richness. This could be a useful reference to someone at a project scale who really wanted to think hard about how to measure biodiversity.

Heilmayr et al. 2020 found that subsidies in Chile to increase tree cover actually led to expansion of exotic plantations (doubling in size from 1986-2011), but decreased native forests (by 13%). They estimate that biodiversity probably declined as well, while aboveground carbon only increased by 2% despite the expansion of plantations.


Allan, J. R., Possingham, H. P., Atkinson, S. C., Waldron, A., Marco, M. Di, Adams, V. M., … Watson, J. E. M. (2019). Conservation attention necessary across at least 44% of Earth’s terrestrial area to safeguard biodiversity. BioRxiv, (November), 839977.

Bhola, N., Klimmek, H., Kingston, N., Burgess, N. D., Soesbergen, A., Corrigan, C., … Kok, M. T. J. (2020). Perspectives on area‐based conservation and its meaning for future biodiversity policy. Conservation Biology, 00(0), cobi.13509.

Fraser, E. D. G., Dougill, A. J., Mabee, W. E., Reed, M., & McAlpine, P. (2006). Bottom up and top down: Analysis of participatory processes for sustainability indicator identification as a pathway to community empowerment and sustainable environmental management. Journal of Environmental Management, 78(2), 114–127.

Gownaris, N. J., Santora, C. M., Davis, J. B., & Pikitch, E. K. (2019). Gaps in Protection of Important Ocean Areas: A Spatial Meta-Analysis of Ten Global Mapping Initiatives. Frontiers in Marine Science, 6(October 2019), 1–15.

Heilmayr, R., Echeverría, C., & Lambin, E. F. (2020). Impacts of Chilean forest subsidies on forest cover, carbon and biodiversity. Nature Sustainability.

Lau, W. W. Y., Shiran, Y., Bailey, R. M., Cook, E., Stuchtey, M. R., Koskella, J., … Palardy, J. E. (2020). Evaluating scenarios toward zero plastic pollution. Science, 21(1), eaba9475.

Tucker, C. M., Cadotte, M. W., Carvalho, S. B., Jonathan Davies, T., Ferrier, S., Fritz, S. A., … Mazel, F. (2017). A guide to phylogenetic metrics for conservation, community ecology and macroecology. Biological Reviews, 92(2), 698–715.