September 2025 science summary

Hi there,

This month I've got three articles on water scarcity, and two on fire and human health in South America. But before I get to the science, here are a couple of very old blog posts and more pictures...

In case you want more pics like the one above, here's an album full of similar pics of snowy mountains and clouds I took on the flight from Punta Arenas (Chile) to Santiago. This was the most beautiful plane flight I've ever taken.

Also, way back in 2013 I wrote an article about how I came to appreciate house centipedes (along w/ nematodes) for their ecological role in pest control, and recently was tickled to see people are still reading and commenting on it 12 years later! Here it is if anyone is curious: https://blog.nature.org/2013/02/08/everyday-nature-how-i-came-to-love-house-centipedes

Finally, the Washington Post and New York Times recently did their own taste tests about real sugar / high fructose corn syrup (including Mexican vs. American Coke) BUT neither was double-blind and neither involved multiple samples of each to improve statistical confidence in the results. Here's one way to do a more rigorous test if you're interested: https://sciencejon.blogspot.com/2012/10/does-real-sugar-make-mexican-coke-taste.html

If you know someone who wants to sign up to receive these summaries, they can do so at http://subscribe.sciencejon.com (no need to email me). OK, with that, here are the science summaries (finally):

FIRE AND HUMAN HEALTH:
dos Santos et al. 2025 found that the smoke plumes from the 2020 Pantanal fire combined with heatwaves, lack of rain to wash smoke particles from the air, and COVID to drive an increase of 21% in premature non-COVID deaths in São Paulo state (see Fig 5) – not counting nonlethal hospitalizations. In other words, improved fire management in the Pantanal could benefit even city dwellers far away. Fig 2 shows the smoke plume trajectories, Fig 3 shows the resulting PM2.5 (small particulate matter air pollution) levels, and Fig 7 is a nice schematic of how the different hazards combine to drive excess mortality. The authors call for more widespread integrated fire management, and continued reductions in sugarcane burning.

Palmeiro-Silva et al. 2025 is an opinion piece arguing that with wildfires increasing across South America, we need to do more to consider human health impacts of fire prevention and management. Using the 2024 wildfires in the Pantanal and the Amazon as a case study, they note that in addition to impacts on the environment and obvious human health impacts like death and air pollution, economic and mental health impacts are also important. They call for better and faster communication to affected communities, co-development of fire plans with local residents, and coordination across multiple sectors to address wildfires via a comprehensive fire risk reduction strategy.


WATER SCARCITY:
Womble et al. 2025 covers several potential ways to address water scarcity (via mandatory cutbacks, several types of water markets focused just on water consumption, and strategically considering impact on fish habitat when selecting places to buy water from). Fig 3 shows the room for improvement from the perspective of fish, often with relatively little extra cost. But an interesting twist is that depending on how the market is structured, the cost and incentives to consider fish habitat varies a lot. The default least cost "authorized market" authorized by the 2019 legislation is not great for fish (the "strategic portfolio" would cost 55% more) but for other markets the extra cost is from <1% to 8% higher to improve fish habitat. Specifically: "strategically investing <1% more funding than a least-cost plan nearly doubles fish habitat improved to intermediate status in an authorized water market with aggressive water-use reductions" and "investing 8% more than a least-cost plan ... nearly triples restored intermediate habitat in an expanded water market with aggressive water-use reductions, more water-user participation and more protections for restored flows". Finally - just 10 transactions yield 1/4 of that potential tripled habitat benefit at 1% of the cost. My overall take-aways are that there could be a lot of secondary effects of market structure, and that a little bit of focused spending to improve fish habitat can have a huge impact!

Given the outsize impact of alfalfa in the SW states, Waring et al. 2025 has some potentially useful ideas about how IF you had a well-designed water market, alfalfa irrigation could be reduced to save water (compensating farmers for reduced yield). Essentially they would cut and sell alfalfa fewer times each year b/c it goes dormant under low water, which they estimate could reduce 16-50% of alfalfa’s water use. See Table 3 for why that’s a big range – it depends on how many fields participate, how many cuttings participating fields have under BAU, and assumptions of irrigation efficiency. Almost half the fields have a short season (3-4 cuttings), which is why in Table 3 you see that scenarios like 3 and 5 that reduce participation by short-season fields result in a lot of missed opportunity. Fig 2d shows the % of total water consumption in each state due to alfalfa from Jul-Oct (note consumption is the amount of water evaporated and transpired from both rain and irrigation, unlike withdrawal which is the volume of irrigation water applied). 

Coelho et al. 2025 shows the trend for overall streamflow and flooding in the Pantanal, and also shows how three upland basins (Jauru, Taquari, and Miranda) connect to their floodplains and the Upper Paraguay (UP) River. I find Fig 11 to be pretty compelling in showing the drying trend for the Pantanal, and Fig 3 shows how the three upland basins flow into their respective floodplains and then to the UP river channel.


REFERENCES:
Coelho, M. E. M. S., Chaves, H. M. L., & Fonseca, M. R. (2025). Trends, Patterns, and Persistence of Rainfall, Streamflow, and Flooded Area in the Upper Paraguay Basin (Brazil). Water, 17(10), 1549. https://doi.org/10.3390/w17101549

dos Santos, D. M., de Oliveira, A. M., Duarte, E. S. F., Rodrigues, J. A., Menezes, L. S., Albuquerque, R., Roque, F. de O., Peres, L. F., Hoelzemann, J. J., & Libonati, R. (2024). Compound dry-hot-fire events connecting Central and Southeastern South America: an unapparent and deadly ripple effect. Npj Natural Hazards, 1(1), 32. https://doi.org/10.1038/s44304-024-00031-w

Palmeiro-Silva, Y., Llerena-Cayo, C., Blanco-Villafuerte, L., Rojas-Rueda, D., Borchers Arriagada, N., Vela-Clavo, Z., de Camargo, T., Rusticucci, M., Valdes-Velasquez, A., & Hartinger, S. M. (2025). The 2024 South America ablaze: health impacts and policy imperatives for protecting population health in an era of wildfires. The Lancet Regional Health - Americas, 48, 101160. https://doi.org/10.1016/j.lana.2025.101160

Waring, E., Dahlke, H. E., Abatzoglou, J. T., Medellín-Azuara, J., Yost, M. A., Bali, K. M., Naughton, C. C., Putnam, D. H., Sabie, R., Kishore, S., Santos, N. R., & Viers, J. H. (2025). Reimagining alfalfa as a flexible crop for water security in the Southwestern USA. Science of The Total Environment, 990(June), 179851. https://doi.org/10.1016/j.scitotenv.2025.179851

Womble, P., Gorelick, S. M., Thompson, B. H., & Hernandez-Suarez, J. S. (2025). A strategic environmental water rights market for Colorado River reallocation. Nature Sustainability. https://doi.org/10.1038/s41893-025-01585-x


Sincerely,
 
Jon
 
p.s. The pic above is one of the many beautiful snow covered mountains I saw in Chile between Punta Arenas and Santiago (in June so during winter). More pics are here: https://www.flickr.com/photos/jaundicedferret/albums/72177720327724315/with/54674270850

July 2025 science summary

 Happy July,

In addition to the usual summaries, I have a request the non-scientists among you (or at least people doing policy or implementation and not JUST science). I have a one-question open-ended survey asking "What one piece of advice would you give scientists to be more effective? What should they do more or less of?" I'd welcome the input and will also share what I hear back in the next summary (and will split the results by advice from scientists and non-scientists if people self-identify). https://forms.cloud.microsoft/r/DXG1n76Q9V  Please reply by Friday July 25 to give me time to read and summarize everything.

The seven summaries cover conservation priorities for birds and people in the US, fire, how fire influences water quantity, and four covering various topics in the Pantanal.

If you know someone who wants to sign up to receive these summaries, they can do so at http://subscribe.sciencejon.com (no need to email me).

CONSERVATION PRIORITIES IN THE U.S. (BIRDS AND PEOPLE):
Neugarten et al. 2025 analyzes overlap of places in the US important to birds with places important for ecosystem services (ES, with climate mitigation broken out separately). They use the 37% of the US producing the most ES (as per Chaplin-Kramer et al. 2023, and from the same paper the 44% of the US storing 90% of vulnerable carbon as carbon priority areas) and bird abundance data form eBird. My TL;DR for this paper is that the natural places people need most help birds better than average, BUT they perform badly for wetland birds and generalists so we need to conserve places good for people AND places good for birds that people don't need as much. Longer take-aways 1) places good for ecosystem services are better than random places for a slight majority of bird species, 2) only 42% of species did better than random w/ carbon priority areas (mostly forest birds as you'd guess), 3) most of the 57 "tipping point" species (who lost 1/2 of their population size over 50 years and are on track to go extinct) don't do well with either ES or carbon priorities, 4) wetland birds and generalists (and to some degree aridland birds) are poorly represented by ES and carbon priorities, 5) "Regions with especially high co-benefits for birds, ES and carbon include the Appalachian Mountains, the southeastern U.S., New England, the Ozarks, and the Sierras and Cascade mountain ranges (Fig. 2a)". This news article has a good summary (although note that my quote about this research being useful to inform where and how conservationists work cut off the end of the sentence which was "along with other strategic considerations" since feasibility and other factors are key). https://news.mongabay.com/short-article/2025/05/study-identifies-us-regions-that-benefit-birds-people-climate-the-most/


FIRE:
Siquiera et al. 2025 has a helpful reminder that finer data isn't always better. They found free MODIS data (which is relatively fast and easy to process due to 500m resolution) actually did a little better at detecting areas that had burned in the Pantanal than Sentinel 2 data (also free but needs more babying and at 10m [2500* finer resolution] it takes a ton more processing time). LANDSAT (at 30m) did worse than either. The only caveat is that their validation for “burned areas” is fire foci which are partly derived from MODIS which likely biases the results somewhat. But anytime we can get away with using coarser data to save time and money it’s good news! One of my papers (https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1002/rse2.61) has a table about when coarser vs. finer data may be better, and that table is in a blog here: https://rsecjournal.blog/2017/08/25/how-much-data-is-enough-investigating-how-spatial-data-resolution-impacts-conservation-decision-making/


FIRE AND WATER QUANTITY:
Guzmán-Rojo et al. 2025 is an interesting model of how fires in the Bolivian Chiquitano dry forest affect water availability, focusing on soil changes (crusting, ash deposition, and reduced porosity which can decrease infiltration and increase runoff) rather than vegetation loss. They found ~40% lower recharge in the first year after a hypothetical very severe fire, returning to ~10% lower than pre-fire after two years. However, they note that field data showed that moderate to severe fires actually reduced soil porosity by 39%, while their hypothetical very severe fire assumed a 70% reduction which is probably an upper bound for how much soil permeability could be reduced. They also note that if they had accounted for vegetation loss in their model, the recharge may have been lower in some areas where dense vegetation transpires more water than it intercepts. While they had limited data to validate their model they used other studies and proxies where they could.


BIODIVERSITY OFFSETTING / PANTANAL:
While Lourival et al. 2025 ponders 10 questions for biodiversity offsetting in the Brazilian Pantanal and its watershed (listed at the top of the 3rd page), it's relevant to biodiversity offsets in general. I especially like Fig 4 with different ways to think about equivalence for offsets (area, economic value, ecosystem value, or a mix). So for example if you clear high-value land in the Cerrado, you could need to protect a much larger lower-value area in the Pantanal. They find 57% of properties in the highlands feeding the Pantanal are out of compliance with the Forest Code (Table 1, Fig 3). Properties WITHIN the Pantanal are only 22% out of compliance, so considering the whole river basin could offer opportunities BUT ecological equivalence may be low and state regulations restrict what is possible. One could argue that's a huge market for offset purchases OR evidence the law is toothless and demand will be low.


PANTANAL:
Guerra et al. 2025 looks at how ecosystem services in the Pantanal and its highlands will change by 2050 under three scenarios (S1 - business as usual (BAU), S2 - increased expansion of ag and industry, and S3 - sustainable intensification). The sustainable scenario could cut soil runoff into rivers almost in half (Figs 4 & 5) and reduce habitat loss by a third compared to BAU (Fig 3). The authors point to some promising new policies that could help the sustainable path, including the growth of the FPS system for ranching and payments for ecosystem services (PES) at national and state (Mato Grosso do Sul) levels, altough there are no PES programs in the Pantanal yet.

Tomasella et al. 2025 found that over recent decades (the time periods are weirdly overlapping and of different length, e.g., 1981-2000 vs 1991-2020) the Pantanal has seen a 4.8% drop in precipitation, 2.9% increase in potential evapotranspiration, and the aridity index (the ratio of those two – with a lower aridity index meaning drier conditions) decreased by 7.5% (brown areas in Fig 5 at right). Fig 3 shows that a chunk of the Pantanal (11,500 km) has dried out enough to change biome from humid to “dry sub-humid.”

Fernandes et al. 2025 uses remote sensing to see how changing sediment loads affected river geomorphology (how the river channel moves over time) in the Cuiabá river in the Pantanal. Stream ecologists often focus on sediment as a pollutant coming from deforestation and agriculture, and that is an issue here (as it is in the nearby Taquari river). But in this case, the construction of the large Manso dam in 2002 has reduced sediment load more than land use change has increased it, perhaps below healthy sediment levels (see Fig 9) for 500km downstream of the dam.


REFERENCES:
Chaplin-Kramer, R., Neugarten, R. A., Sharp, R. P., Collins, P. M., Polasky, S., Hole, D., Schuster, R., Strimas-Mackey, M., Mulligan, M., Brandon, C., Diaz, S., Fluet-Chouinard, E., Gorenflo, L. J., Johnson, J. A., Kennedy, C. M., Keys, P. W., Longley-Wood, K., McIntyre, P. B., Noon, M., … Watson, R. A. (2022). Mapping the planet’s critical natural assets. Nature Ecology & Evolution, 7(1), 51–61. https://doi.org/10.1038/s41559-022-01934-5

Fernandes, B. S., de Oliveira, S. C., & Pupim, F. N. (2025). Anthropogenic disturbances drive the morphological and sedimentary changes of the Cuiabá River, Pantanal, Brazil: a remotely sensed approach. Earth Science, Systems and Society. https://doi.org/10.1144/esss2024-007

Guerra, A., Resende, F., Bergier, I., Fairbrass, A., Bernardino, C., Centurião, D. A. S., Bolzan, F., Marcel, G., Rosa, I. M. D., da Silva, J. C. S., Garcia, L. C., Larcher, L., de Oliveira, P. T. S., Chiaravalloti, R. M., Roscoe, R., Louzada, R., Santos, S., Tomas, W. M., Nunes, A. V., & de Oliveira Roque, F. (2025). Land use and regulating ecosystem services scenarios for the Brazilian Pantanal and its surroundings under different storylines of future regional development. Conservation Science and Practice, August 2024, 1–16. https://doi.org/10.1111/csp2.70012

Guzmán-Rojo, M., Silva de Freitas, L., Coritza Taquichiri, E., & Huysmans, M. (2025). Groundwater Vulnerability in the Aftermath of Wildfires at the El Sutó Spring Area: Model-Based Insights and the Proposal of a Post-Fire Vulnerability Index for Dry Tropical Forests. Fire, 8(3), 86. https://doi.org/10.3390/fire8030086

Lourival, R. F. F., de Roque, F. de O., Bolzan, F. P., Guerra, A., Nunes, A. P., Lacerda, A. C. R., Nunes, A. V., Alves, A., Filho, A. C. P., Ribeiro, D. B., Eaton, D. P., Brito, E. S., Fischer, E., Neto, F. V., Porfirio, G., Seixas, G. H. F., Pinto, J. O. P., Quintero, J. M. O., Sabino, J., … Tomas, W. M. (2025). Ten relevant questions for applying biodiversity offsetting in the Pantanal wetland. Conservation Science and Practice, July 2022, 1–21. https://doi.org/10.1111/csp2.13274

Neugarten, R. A., Davis, C. L., Duran, G., & Rodewald, A. D. (2025). Co-benefits of nature for birds, people, and climate in the United States. Ecosystem Services, 73(May), 101733. https://doi.org/10.1016/j.ecoser.2025.101733

Siqueira, R. G., Moquedace, C. M., Silva, L. V., de Oliveira, M. S., Cruz, G. D. B., Francelino, M. R., Schaefer, C. E. G. R., & Fernandes-Filho, E. I. (2025). Do finer-resolution sensors better discriminate burnt areas? A case study with MODIS, Landsat-8 and Sentinel-2 spectral indices for the Pantanal 2020 wildfire detection. International Journal of Remote Sensing, 00(00), 1–24. https://doi.org/10.1080/01431161.2025.2496000

Tomasella, J., do Amaral Cunha, A. M., Zeri, M., & Costa, L. C. O. (2025). Changes in the aridity index across Brazilian biomes. Science of The Total Environment, 989(March), 179869. https://doi.org/10.1016/j.scitotenv.2025.179869


Happy reading,
 
Jon
 
p.s. The photo above was an especially vivid winter sunset in Wildwood, NJ