October 2023 science summary

Greetings,

This month I have just two articles - one on conservation priorities (a longer than usual review) and one on how mining affects tropical rivers. I also forgot to post on this site for a few weeks, sorry!

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CONSERVATION PRIORITIES:
Mair et al. 2021 proposes the use of a "species threat abatement and restoration (STAR)" metric with two scores. The threat abatement one for a location (START) sums up each threatened species present, with higher threat like Critically Endangered scoring higher, favoring locations with more species that are more threatened. The idea is to estimate effort to abate all threats (which seems unreasonable). The restoration score (STARR) divides 'restorable habitat' for all threatened species in a given pixel by global habitat for that species, and sums across species.

The paper calculates both for threatened terrestrial vertebrates. START results look pretty similar to range-size rarity scores for threatened species or a few other existing metrics, and suffer from the same issues (bias to data-rich places, lack of accurate info in many places). STARR seems more conceptually interesting but I'm pretty suspicious that the projected range maps are valid (given issues w/ current range maps) and since they didn't screen out any low-feasibility areas (like highly productive ag) it doesn't seem too useful. I also struggle to understand how they could have come up with the map in Fig 2b using the methods they describe. But that could be me being slow rather than a problem with the analysis.

FRESHWATER:
Dethier et al 2023 (briefly summarized in Walmsley 2023) finds that mining in tropical countries is dramatically increasing sediment in rivers. 80% of the 173 rivers affected by mining that they studied had sediment concentrations more than double what they were prior to mining. This is a pretty coarse estimate using satellite data, so the actual sediment estimates are very rough, but the general pattern should be valid.


REFERENCES:
Dethier, E. N., Silman, M., Leiva, J. D., Alqahtani, S., Fernandez, L. E., Pauca, P., Çamalan, S., Tomhave, P., Magilligan, F. J., Renshaw, C. E., & Lutz, D. A. (2023). A global rise in alluvial mining increases sediment load in tropical rivers. Nature, 620(7975), 787–793. https://doi.org/10.1038/s41586-023-06309-9

Mair, L., Bennun, L. A., Brooks, T. M., Butchart, S. H. M., Bolam, F. C., Burgess, N. D., Ekstrom, J. M. M., Milner-Gulland, E. J., Hoffmann, M., Ma, K., Macfarlane, N. B. W., Raimondo, D. C., Rodrigues, A. S. L., Shen, X., Strassburg, B. B. N., Beatty, C. R., Gómez-Creutzberg, C., Iribarrem, A., Irmadhiany, M., … McGowan, P. J. K. (2021). A metric for spatially explicit contributions to science-based species targets. Nature Ecology & Evolution, 5(6), 836–844. https://doi.org/10.1038/s41559-021-01432-0

Walmsley, B. (2023). Satellite images show the widespread impact of mining on tropical rivers. Nature, 620(7975), 729–730. https://doi.org/10.1038/d41586-023-02349-3

Sincerely,
 
Jon
 
p.s. This is a photo of a giant anteater that I saw on a recent trip to the Pantanal in Brazil. If you're curious I have more Pantanal photos and Pantanal videos.