August 2021 science summary

Hi,

This month is a grab bag of a few articles on different topics I've been meaning to read. Sorry for the lack of a theme!

If you know someone who wants to sign up to receive these summaries, they can do so at http://bit.ly/sciencejon

BIODIVERSITY / ECOLOGY:
Maron et al. 2021 offers seven guidelines to set robust biodiversity goals (aimed at the Global Biodiversity Framework [GBF] under CBD), summarized in a nice diagram in Fig 1. 1. recognize limits to "net outcome" approaches (determine which spp and ecosystems are irreplaceable), 2. use net outcomes where needed since some losses are unavoidable, 3. specify a timeline for net outcome goals (a reference year and a target year), 4. set goals for net gains (since a reference year like 2020 has some spp. and ecosystems which have experienced high historic loss, so net gaines are needed to persist), 5. capture key biodiversity (with distinct goals for ecosystems, spp., and genetic diversity), 6. avoid unintended substitutions by ensuring any losses to one species (or ecosystem) is balanced with gains to a different one only if the losses are to a relatively unthreatened component, and 7. set ambitious goals (achievable, but more than adequate). They note several changed needed to the post-2020 GBF to meet these criteria.

Lutz et al. 2018 asks how important the biggest trees in forests are across the world. My favorite figure is that the biggest 1% in diameter made up ~50% of the aboveground biomass (of trees bigger than 1 cm), although with lots of variation by forest. If you use a consistent threshold of trees >2' in diameter instead of the top 1%, they're ~40% of biomass on average. Forests where the biggest trees took up a bigger % of total biomass tended to have fewer species in that top size class. They point out that for carbon sequestration, these big trees are super important, which Bill Moomaw has also emphasized in advocating for 'proforestation' where we just leave forests alone for longer before logging them as the rate of sequestration goes up as they get really big.

Hall et al. 2021 is about Circuitscape (software to analyze wildlife connectivity at the landscape scale) and the advantages of having ported it over to Julie (a high-performance computing language). From figure 3 it looks like the new version is about 7 times as fast as the python version, and it runs as a standalone without needing to know Julia. They make the broader point that collaborating with computer scientists can reduce costs and improve efficiency, allowing more conservation to get done.


SOCIAL SCIENCE:
Dieckman et al. 2021 surveyed people about how important different social and cultural issues were to government decision makers vs. the general public. Respondents thought that government decision makers care the most about economic aspects, but that the public cares more about other social and cultural aspects. More tangible impacts (like water quality and physical safety) were perceived to be more important than intangible ones (like emotional health and local practices). Interestingly, biodiversity had the lowest perceived support second only to native culture.


REFERENCES:

Dieckmann, N. F., Gregory, R., Satterfield, T., Mayorga, M., & Slovic, P. (2021). Characterizing public perceptions of social and cultural impacts in policy decisions. Proceedings of the National Academy of Sciences, 118(24), e2020491118. https://doi.org/10.1073/pnas.2020491118

Hall, K. R., Anantharaman, R., Landau, V. A., Clark, M., Dickson, B. G., Jones, A., Platt, J., Edelman, A., & Shah, V. B. (2021). Circuitscape in Julia: Empowering Dynamic Approaches to Connectivity Assessment. Land, 10(3), 301. https://doi.org/10.3390/land10030301

Lutz, J. A., Furniss, T. J., Johnson, D. J., Davies, S. J., Allen, D., Alonso, A., Anderson-Teixeira, K. J., Andrade, A., Baltzer, J., Becker, K. M. L., Blomdahl, E. M., Bourg, N. A., Bunyavejchewin, S., Burslem, D. F. R. P., Cansler, C. A., Cao, K., Cao, M., Cárdenas, D., Chang, L.-W., … Zimmerman, J. K. (2018). Global importance of large-diameter trees. Global Ecology and Biogeography, 27(7), 849–864. https://doi.org/10.1111/geb.12747

Maron, M., Juffe-Bignoli, D., Krueger, L., Kiesecker, J., Kümpel, N. F., ten Kate, K., Milner-Gulland, E. J., Arlidge, W. N. S., Booth, H., Bull, J. W., Starkey, M., Ekstrom, J. M., Strassburg, B., Verburg, P. H., & Watson, J. E. M. (2021). Setting robust biodiversity goals. Conservation Letters, May, 1–8. https://doi.org/10.1111/conl.12816

Sincerely,
 
Jon