Thursday, June 1, 2017

June journal article summary


I did a lot more writing than reading last month so this review is a more reasonable length than the last one. I don't want to always highlight one paper in these but if you have time for only one, read Bastin both because of the significance of having more accurate dryland forest maps, but also because it's short and the methods are interesting (the photo above of logging in Indonesia is more appropriate for the Gaveau paper).

Also, this isn't an article, but if you publish in science journals, please take a moment to check out and consider submitting reviews for the journals you have published in. The site is intended to show both how long the review and publication process takes at different journals, as well as how well the process went. Currently I have one paper about to be published in IJRS which was fast and provided extremely insightful and helpful review, and a few others where the process has been slow and unhelpful. This site can help us figure out which journals to target so we waste less time with bad editorial process. Please spread the word!

Bastin et al 2017 is a really cool new paper mapping global dryland forests. Think of it as an update to the Hansen global forest paper, but focusing on drylands (aridity index<0.65) and incorporating very high resolution imagery (<1m in 82% of the 214k plots, using >10m in only 7%) and ground photos to improve accuracy (although the higher resolution data necessitated measuring sample plots rather than directly processing all imagert) . They found 40-47% more dryland forest than previously reported, adding 9% to estimates of global forest cover (and potentially 2-20% to global carbon stocks). This is a good example of how in some cases higher resolution data can tell a different story, although there are several accompanying challenges as well to consider. The data is public and will be useful for other research, as will the methodology (be sure to check out the supplement if you're into remote sensing, especially figures S1 and S2 which visually explain the approach).

Ahrends et al 2017 also used remote sensing to look at forests, but they focused on tree planting in China. They found that from 2000-2010, China gained almost half a million square km of forest using the FAO's definition, but that is generally sparse low plantations, and denser forests have grown <10% of that figure. China's investment in reforestation (while a good thing) is focusing in areas marginal for forest growth (e.g. mountain slopes which are steep, high, dry, and cold) which means they are unlikely to lead to what most people think of as "forest." A key caveat is that one of the study's criteria for forest (height over 5m) makes sense for established stands, but it seems to me that it is misleading to argue that trees planted in the last ten years not growing past 5m necessarily represents failure of those efforts. However, the points about afforestation being concentrated on unsuitable lands is important, as is the prevalence of single species plantations. This really highlights the importance of good definitions, good measurements, and careful interpretation of the measurements. You can read a blog about this one at

Gaveau et al 2016 looks at deforestation and expansion of plantations in Borneo between 1973 and 2015, in order to detemine how much plantations were replacing already degraded forest or driving new deforestation. They found that most new plantations were established within 5 years of deforestation, especially in Malaysia (indicating that they are likely the cause, although attribution isn't certain). While Indonesia's deforestation over the last 40 years appears to have been much less driven by plantations, since 2005 it has sharply increased and is the leading cause of rapid net forest conversion. It's an interesting read, and if you plan to use their data be sure to check out the caveats section.

My latest paper (Ayana et al. 2017, the first author Essayas was a NatureNet fellow) describes a method we used to map drainage ditches and furrows on farms in Kenya using high-resolution satellite imagery, and has a rough analysis showing that these features could be reducing sediment export in the study area by about 80%. The technical aspect which is the core of the paper will not be of interest to many people reading this. But the key point is that it's important to have this information to build a reasonable water quality model of the area, and this method makes acquiring that information possible (it would be too expensive to map via field work alone). Feel free to share this one, you can download it from and if I use up my 50 free eprints I'll put a copy on my personal web site.

Vollmer-Sanders et al 2016 is a TNC-led article about efforts to get farmers in the Western Lake Erie Basin to get voluntarily certified in the 4Rs (to reduce nutrient pollution). They were able to reach 35% of farmland in the Basin within two years, and this paper describes how the certification program was developed by a broad group of stakeholders. They don't yet have outcome measures on water quality, crop yield, etc. but should have data by July 2019, by which point they hope to have continued to get more farms on board.

Tomer and Locke 2011 is a synthesis from CEAP (Conservation Effects Assessment Project) about the efficacy of various ag practices in improving water quality. Similar to other studies, they found improving water quality in large watershed very challenging both to achieve and to measure. They identified a few key barriers to success: 1) conservation practices were insufficiently targeted, 2) stream sediment was predominantly from channel & bank erosion rather than soil erosion from fields, 3) timing lags and legacy issues can mask improvements for several years, and 4) focusing on single contaminants prevented optimizing across them (e.g. focusing on P rather than P / N / sediment).

Amel et al 2017 is a review of the need for applying research in psychology about how to shift human behavior in order to meet conservation goals (something Sheila Reddy at TNC has been focusing on for some time). They argue that most people feel disconnected from nature and since they don't see short-term threats to them from environmental degradation they are unmotivated to act (they call these and other causes "dragons of inaction"). There's a good brief review of how to design interventions to overcome these barriers to action. Since moving beyond individual action to public advocacy is more challenging they focus on the need to foster collective action and  to instill an ecologically grounded worldview in leaders. They conclude with the need to improve the ability of city dwellers to connect with nature. Folks interested in this topic may also be interested in a recent paper Sheila wrote on how to pick the right approach for a given context:

It's not a journal article, but "The Undoing Project" by Michael Lewis is both a highly entertaining read, as well as a great way to get up to speed in learning about some of the ways our minds systematically make errors due to biases we are generally unaware of. It's told through stories about Daniel Kahneman and Amos Tversky, so while the author does get into the science it's in a very accessible way. As you read, you will likely be shocked and annoyed to see that you are not immune to these biases and errors, but the reason the book is so fascinating is that they are fairly universal even among statisticians. This research changed science and medicine in significant ways, and I think virtually anyone would find it interesting for one reason or another.

Ahrends, A., Hollingsworth, P. M., Beckschäfer, P., Chen, H., Zomer, R. J., Zhang, L., … Xu, J. (2017). China’s fight to halt tree cover loss. Proceedings of the Royal Society of London B: Biological Sciences, 284(1854), 1–10. Retrieved from

Amel, E., Manning, C., Scott, B., & Koger, S. (2017). Beyond the roots of human inaction: Fostering collective effort toward ecosystem conservation. Science, 356(6335), 275–279.

Ayana, E. K., Fisher, J. R. B., Hamel, P., & Boucher, T. M. (2017). Identification of ditches and furrows using remote sensing: application to sediment modelling in the Tana watershed, Kenya. International Journal of Remote Sensing, 38(16), 4611–4630.

Bastin, J.-F., Berrahmouni, N., Grainger, A., Maniatis, D., Mollicone, D., Moore, R., … Castro, R. (2017). The extent of forest in dryland biomes. Science, 356(6338), 635–638.

Gaveau, D. L. A., Sheil, D., Husnayaen, Salim, M. A., Arjasakusuma, S., Ancrenaz, M., … Meijaard, E. (2016). Rapid conversions and avoided deforestation: examining four decades of industrial plantation expansion in Borneo. Scientific Reports, 6(October 2015), 32017.

Lewis, M. (2017). The undoing project. A Friendship that changed our Minds” New York: WW Norton & Company.

Tomer, M. D., & Locke, M. A. (2011). The challenge of documenting water quality benefits of conservation practices: A review of USDA-ARS’s conservation effects assessment project watershed studies. Water Science and Technology, 64(1), 300–310.

Vollmer-Sanders, C., Allman, A., Busdeker, D., Moody, L. B., & Stanley, W. G. (2016). Building partnerships to scale up conservation : 4R Nutrient Stewardship Certification Program in the Lake Erie watershed. Journal of Great Lakes Research, 42(6), 1395–1402.