May 2025 science summary

Merry May,

This month I've got four articles on freshwater, plus one on whether climate mitigation can be harmful to wildlife if done wrong (spoiler: yup).

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

FRESHWATER:
Petry et al. 2025 has predictions of changing streamflow and flooding across South America by 2100 under a moderate climate change scenario. Figure 4 has the key findings about how much more or less frequent floods may be. Note that “RP” means “return period” as in a “5 year flood” or “100 year flood” (the magnitude of flooding you’d expect on that frequency / rarity, so higher numbers mean more severe flooding). RPCF means how much more or less frequent those floods would be (with negative sign indicating less frequent flooding, e.g. the -2 on the Paraguay river in the Pantanal means half as often). But much more flooding is expected in Peru, Ecuador, Colombia, and Southern Brazil, and parts of the Amazon will see 1/10 as much flooding as they historically have. They find Pantanal floods (in the Paraguay River and some tributaries like Cuiaba and Negro) will be roughly half as frequent and half as severe, they don’t have a clear trend in the Chaco, and in Chile the area from roughly Santiago to Valdivia has some rivers where flooding will be ~2-3 times less frequent while the northern part of Chile will only see slightly less flooding.

Lehner et al. 2024 is a summary of a new "Global Dam Watch (GDW)" open dataset of 41,000 river barriers and 35,000 reservoirs (see Fig 1 for a map). While national and regional datasets are more complete (e.g., NID has 90k points in the US, AMBER has 630k in Europe), this is the most comprehensive free global dataset (see Table 2) and it includes estimated reservoir volumes mostly for reservoirs >10 km2.

Cho et al. 2023 did a ton of modeling (Fig 7) to estimate how conservation (mostly reforestation along streams) could have affected the water supply of São Paulo. They found the increased habitat could serve as an "invisible reservoir" for water in soil, and in a highly idealized scenario (lots of new forest in all the right places among others) streamflow could be boosted by 33% (and drought costs reduced by 28%). They don't report numeric results for their less ideal scenarios, and all scenarios exclude the water consumption of growing trees. In a conversation with one of the study's authors, they mentioned that it likely took about 30 years (I think) for the "water savings" of nature (fog capture plus slowing down runoff during high rain events) to outweigh the water consumption of growing trees. In other words, in this case in the short term adding trees could result in lower streamflow even though in the long run it would increase streamflow. Understanding the timeline and tradeoffs is key so people who live there know what to expect. From chatting w/ other hydrologists about this, it's clear that results like this vary a lot depending on things like soil type, weather and climate, type of forest, and much more. There's an article about this one at https://www.nature.org/en-us/about-us/where-we-work/latin-america/brazil/stories-in-brazil/invisible-reservoir/

Pompeu 2025 quantitatively models how different drivers have impacted total water surface area (as a decent proxy for total flow / water quantity) in the Pantanal. The paper found the biggest driver of water level was 1) the presence or absence of having natural vegetation at least 50m around springs, followed by 2) natural veg riparian buffers along rivers (buffer width increasing w/ river width as per the Forest Code), followed by 3) replacing conventional monoculture ag w/ something w/ deeper root systems (agroforestry, permaculture, full restoration if feasible, etc.), followed by 4) preventing more dams.


CLIMATE MITIGATION AND WILDLIFE:
Smith et al. 2025 asks what the net impact of climate mitigation on land (including bioenergy crops, reforestation, and afforestation) is on the total habitat area for 14,000 vertebrate species. Fig 1 summarizes the idea well - climate change can reduce suitable habitat, but climate mitigation can also either add or remove habitat directly. Fig 4 has their global recommendations - basically leave most ecosystems alone, reforest several areas (SE Asia, Eastern US, Mexico, and much of Europe) and in a few tiny places grow bioenergy crops. In other words, typically planting trees on grasslands or other habitat types destroys more habitat than it saves through climate mitigation. But planting trees in cleared forests is a win-win.


REFERENCES:
Cho, S. J., Klemz, C., Barreto, S., Raepple, J., Bracale, H., Acosta, E. A., Rogéliz-Prada, C. A., & Ciasca, B. S. (2023). Collaborative Watershed Modeling as Stakeholder Engagement Tool for Science-Based Water Policy Assessment in São Paulo, Brazil. Water, 15(3), 401. https://doi.org/10.3390/w15030401

Lehner, B., Beames, P., Mulligan, M., Zarfl, C., De Felice, L., van Soesbergen, A., Thieme, M., Garcia de Leaniz, C., Anand, M., Belletti, B., Brauman, K. A., Januchowski-Hartley, S. R., Lyon, K., Mandle, L., Mazany-Wright, N., Messager, M. L., Pavelsky, T., Pekel, J.-F., Wang, J., … Higgins, J. (2024). The Global Dam Watch database of river barrier and reservoir information for large-scale applications. Scientific Data, 11(1), 1069. https://doi.org/10.1038/s41597-024-03752-9

Petry, I., Miranda, P. T., Paiva, R. C. D., Collischonn, W., Fan, F. M., Fagundes, H. O., Araujo, A. A., & Souza, S. (2025). Changes in Flood Magnitude and Frequency Projected for Vulnerable Regions and Major Wetlands of South America. Geophysical Research Letters, 52(5). https://doi.org/10.1029/2024GL112436

Pompeu, J. (2025). Cross-Boundary Drivers of Water Cover Reduction in the Pantanal Wetland and Implications for its Conservation. Wetlands, 45(3), 32. https://doi.org/10.1007/s13157-025-01916-w

Smith, J. R., Beaury, E. M., Cook-Patton, S. C., & Levine, J. M. (2025). Variable impacts of land-based climate mitigation on habitat area for vertebrate diversity. Science, 387(6732), 420–425. https://doi.org/10.1126/science.adm9485


Sincerely,
 
Jon

p.s. This is a sea lion lazing about in Valdivia who happened to yawn as I was watching them.

April 2025 science summary

Hello,

This month I thought people might be interested in a short overview I pulled together about some of the fires in recent years and the impact they've had (instead of only detailed summaries of each paper). Let me know what you think! I do have normal summaries of four papers on fire (two mentioned in the overview) as well.

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

FIRE OVERVIEW:
Earlier this year in and around one of the largest cities in the US, almost 50,000 acres burned (https://www.fire.ca.gov/incidents/2025), destroying >16,000 buildings, displacing tens of thousands of people, and causing an estimated damage of >$250 billion dollars (https://www.nbcnews.com/news/us-news/california-wildfires-what-we-know-palisades-eaton-los-angeles-rcna188239).  This follows an exceptional fire season across North and South America in 2024 (https://earth.org/north-and-south-america-endured-exceptional-wildfire-season-in-2024/). 

Experts estimate that there has been a “ten‑fold increase in the frequency of fire regime change during the last 250 years,” (Sayedi et al. 2024) and wildland fuels have almost universally been getting dryer over the last 40 years (Ellis et al. 2022). While fire is normal in many ecosystems (and essential in some), we also have many recent examples of fires which devastated nature due to unusual severity, scale, speed, and return intervals. For example, in 2019-20, after severe drought in Australia a fire burned over 25 million acres (>100,000 km2) and “killed or displaced an estimated 3 billion mammals, birds, frogs, and reptiles” (Legge et al. 2023). The Pantanal has had increasingly common severe fires, e.g., in 2020 almost half of the ~10 million acres that burned hadn’t burned before in the last 20 years (Garcua et al. 2021), killing roughly 17 million vertebrates (Tomas et al. 2021). 

In some cases severe fire can also lead to high greenhouse gas emissions, especially for peatlands. For example, in 1997-8 Indonesian peat fires emitted a gigaton of carbon (~15% of global fossil fuel emissions, Turetsky et al. 2015). 

There is hope: our ability to remotely detect forest fires early is improving (Barmpoutis et al. 2020), and Indigenous fire brigades have shown promise as a low-cost way to dramatically reduce harmful wildfire (Ribeiro et al. 2023). 


SUMMARIES OF SPECIFIC FIRE PAPERS:
GLOBAL FIRE:
Ellis et al. 2022 is a global analysis of fire risk over the past 41 years, using estimated moisture trends in fuel (surface litter and dead plant debris) as the key metric. Fig 2a shows the % of days during the fire season where fuel moisture is expected to be below 10% (and thus at high fire risk), while 2b shows the total # of fire season days at high fire risk and Fig 4 shows the trend in high fire risk over time (36% of ecoregions are drying vs. only 4% getting wetter). They note that days w/ dry fuel isn't the only key driver of risk; consistent dry conditions limit fuel accumulation and thus the risk of severe fire. So surprisingly historically wet forests which accumulate lots of plant matter in wet years between fires may be the most at risk (as other research has shown).


FIRE IN SOUTH AMERICA:
Feron et al. 2024 analyzes how fire risk in South America has increased in the last 52 years (especially in the North Amazon). They estimate fire risk by combining the increasing number of warm days, dry days, and flammable days (combined in Fig 3). El Niño worsens risk in the Nothern Amazon, but lessens it in the Gran Chaco (where La Niña worsens the risk). The northeast part of the Gran Chaco has seen the most increase in fire risk (Fig 1a). The authors note that where humans set fires is also a key driver of wildfires spreading. In the Amazon severe fire has caused local warming (from black carbon) and decreasing rainfall.

Barros-Rosa et al. 2025 is a complex analysis of water and fire in the Pantanal and Planalto in Brazil. They looked at changes in land use and water and fire from 1985 to 2022. They found 1) open water in the Pantanal dropped from 20% to 5% (this analysis has a very high rate of error and variance so the precise numbers are likely wrong but the overall drying trend is valid), 2) forest and savanna were cleared for cattle (replacing them with exotic grass - doubling in the Planalto and tripling in the Pantanal), although 3) native grasslands also doubled in the Pantanal. They also find areas that have dried out are the most affected by wildfires. The authors also highlight existing policies allowing massive conversion of habitat to exotic grass, and allowing artificial drainage in wetlands outside the Pantanal.

Oliveira et al. 2025 argues that rigid "burn windows" when prescribed fire should be done works poorly in wetlands like the Pantanal (where the government limits prescribed fire to the beginning of the dry season (BDS), a ~5 month period as shown in Fig. 2). Burn windows remain important: prescribed fire requires considering both fuel loads and how wet or dry it is to ensure fire can burn but remains contained, as well as things like wind direction that could affect human health. But flooding combines w/ rainfall to determine actual fuel loads, limiting the utility of prescribed fire when rain is low but flooding remains. Considering river height as a proxy for flooding they find the end of the BDS is typically ideal for prescribed fire (although varying year to year, Fig. 6) even though rainfall is much lower than the beginning of BDS when flooding limits the use of prescribed fire (Fig. 4b and 4c). But they note that in the Northern Pantanal where rain and flood are more aligned than the Southern Pantanal the burn window is longer and more predictable (Fig. 5). The conclude that in wetlands like the Pantanal burn windows should be dynamic year to year and consider flooding as well as rainfall. One key point: prescribed burning is more important in high flood years, b/c while the window is shorter, flooding allows more vegetation to accumulate which raises the risk of fire once floods recede (we've often see severe fires in the Pantanal the year after a very wet year).


REFERENCES FOR PAPERS SUMMARIZED INDIVIDUALLY:
Ellis, T. M., Bowman, D. M. J. S., Jain, P., Flannigan, M. D., & Williamson, G. J. (2022). Global increase in wildfire risk due to climate‐driven declines in fuel moisture. Global Change Biology, 28(4), 1544–1559. https://doi.org/10.1111/gcb.16006

Feron, S., Cordero, R. R., Damiani, A., MacDonell, S., Pizarro, J., Goubanova, K., Valenzuela, R., Wang, C., Rester, L., & Beaulieu, A. (2024). South America is becoming warmer, drier, and more flammable. Communications Earth & Environment, 5(1), 501. https://doi.org/10.1038/s43247-024-01654-7

Barros-Rosa, L., Moura Peluso, L., Lemes, P., Johnson, M. S., Dalmagro, H. J., Nunes da Cunha, C., Zanella de Arruda, P. H., Mateus, L., & Penha, J. (2025). The ineffectiveness of current environmental and fire policies in the world’s largest wetland. Environmental Research Letters, 20(3), 034039. https://doi.org/10.1088/1748-9326/adb7f5

Oliveira, M. da R., Pereira, A. de M. M., Bao, F., Ferreira, B. H. dos S., Fernando, A. E., Roque, F. de O., Pott, A., Damasceno-Junior, G. A., & Neves, D. R. M. (2025). Designing Burn Windows for Integrated Fire Management in Wetlands: Why Should Flooding Not Be Overlooked? Wetlands, 45(4), 35. https://doi.org/10.1007/s13157-025-01919-7


REFERENCES FOR OTHER PAPERS IN OVERVIEW:
Barmpoutis, P., Papaioannou, P., Dimitropoulos, K., & Grammalidis, N. (2020). A Review on Early Forest Fire Detection Systems Using Optical Remote Sensing. Sensors, 20(22), 6442. https://doi.org/10.3390/s20226442

Garcia, L. C., Szabo, J. K., de Oliveira Roque, F., de Matos Martins Pereira, A., Nunes da Cunha, C., Damasceno-Júnior, G. A., Morato, R. G., Tomas, W. M., Libonati, R., & Ribeiro, D. B. (2021). Record-breaking wildfires in the world’s largest continuous tropical wetland: Integrative fire management is urgently needed for both biodiversity and humans. Journal of Environmental Management, 293(April), 112870. https://doi.org/10.1016/j.jenvman.2021.112870

Legge, S., Rumpff, L., Garnett, S. T., & Woinarski, J. C. Z. (2023). Loss of terrestrial biodiversity in Australia: Magnitude, causation, and response. Science, 381(6658), 622–631. https://doi.org/10.1126/science.adg7870

Ribeiro, D. B., & Pereira, A. M. M. (2023). Solving the problem of wildfires in the Pantanal Wetlands. Perspectives in Ecology and Conservation, 21(4), 271–273. https://doi.org/10.1016/j.pecon.2023.10.004

Sayedi, S. S., Abbott, B. W., Vannière, B., Leys, B., Colombaroli, D., Romera, G. G., Słowiński, M., Aleman, J. C., Blarquez, O., Feurdean, A., Brown, K., Aakala, T., Alenius, T., Allen, K., Andric, M., Bergeron, Y., Biagioni, S., Bradshaw, R., Bremond, L., … Daniau, A.-L. (2024). Assessing changes in global fire regimes. Fire Ecology, 20(1), 18. https://doi.org/10.1186/s42408-023-00237-9

Tomas, W. M., Berlinck, C. N., Chiaravalloti, R. M., Faggioni, G. P., Strüssmann, C., Libonati, R., Abrahão, C. R., do Valle Alvarenga, G., de Faria Bacellar, A. E., de Queiroz Batista, F. R., Bornato, T. S., Camilo, A. R., Castedo, J., Fernando, A. M. E., de Freitas, G. O., Garcia, C. M., Gonçalves, H. S., de Freitas Guilherme, M. B., Layme, V. M. G., … Morato, R. (2021). Distance sampling surveys reveal 17 million vertebrates directly killed by the 2020’s wildfires in the Pantanal, Brazil. Scientific Reports, 11(1), 23547. https://doi.org/10.1038/s41598-021-02844-5

Turetsky, M. R., Benscoter, B., Page, S., Rein, G., Van Der Werf, G. R., & Watts, A. (2015). Global vulnerability of peatlands to fire and carbon loss. Nature Geoscience, 8(1), 11–14. https://doi.org/10.1038/ngeo2325

Sincerely,
 
Jon
 
p.s. The picture is of the first drum circle I ever attended, which was at work during  a "learning week" event for my department!

p.p.s. Nothing in this post is an April Fool's joke or untrue in any way as far as I know :)

March 2025 science summary

Greetings,

Work has been pretty hectic so I've been reading less public science papers lately but have two good ones to share on "old and wise animals" and freshwater prioritization.

Like many others, I've also been struggling with the chaos and hurtful policy and people suffering from the recent political changes in the US.

I don't have answers, but have been finding that connection, community, being vulnerable, and supporting each other is helpful. As is finding joy wherever we can. In that spirit, here's a video of a song my chorus sang last December where I had a solo - I find it painful to watch all the mistakes but it was a joy to sing in the real world, and hope it may distract a few of you from everything going on in the world for a moment or two.

I've also found this document of things to say and not say to someone grieving can still be helpful in comforting people going through other tough situations. The main point is to resist the impulse to cheer them up and instead validate their feelings and be willing to just sit with the discomfort.

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


WILDLIFE:
Kopf et al 2024 really made me think. They summarize some of the important contributions of old (and often "wise"!) animals, and proposes "longevity conservation" as a strategy to retain them. Old animals are especially important for species who rely on cultural transmission (like migratory species) and those who reproduce more as they age and grow, and the article goes into detail with examples of both. The article also covers some of the impacts of losing large and old animals, like changing ecosystem structure and function, pack instability, and even infanticide. The ability of older animals to help their group adapt to drought or food shortages maybe increasingly important as climate changes (although the individual resilience of older animals is likely to lower to some stresses like disease). With trophy hunting and fishing selecting for larger (typically older) animals, they argue for the importance of better population modeling, setting age class targets for fisheries, restricting hunting of larger and older animals, and going beyond tracking biomass or abundance to watch for "longevity depletion."


FRESHWATER:
Sayer et al. 2025's headline is that 1/4 of freshwater animals are threatened with extinction. But that's similar to other estimates; to me the new thing here is guidance on how to prioritize sites to conserve with limited data. They found that 1) prioritizing with just threatened freshwater tetrapod data (animals with four legs like some amphibians, reptiles, birds, and mammals) does well for overall freshwater biodiversity (range-size rarity) but 2) prioritizing on abiotic factors alone (low flow / water stress, nitrogen as a proxy for water pollution) does worse than random! Also from Fig 2b permanent rivers are home to almost all of the threatened FW species, while species in other fresh wetlands fare much better.


REFERENCES:
Kopf, R. K., Banks, S., Brent, L. J. N., Humphries, P., Jolly, C. J., Lee, P. C., Luiz, O. J., Nimmo, D., & Winemiller, K. O. (2024). Loss of Earth’s old, wise, and large animals. Science, 2705, 1–19. https://doi.org/10.1126/science.ado2705

Sayer, C. A., Fernando, E., Jimenez, R. R., Macfarlane, N. B. W., Rapacciuolo, G., Böhm, M., Brooks, T. M., Contreras-MacBeath, T., Cox, N. A., Harrison, I., Hoffmann, M., Jenkins, R., Smith, K. G., Vié, J.-C., Abbott, J. C., Allen, D. J., Allen, G. R., Barrios, V., Boudot, J.-P., … Darwall, W. R. T. (2025). One-quarter of freshwater fauna threatened with extinction. Nature, 3(December 2023). https://doi.org/10.1038/s41586-024-08375-z


Sincerely,
 
Jon
 
p.s. This is a photo of a whitewater rafting trip in Chile w/ colleagues. It was beautiful and a great time albeit painful as my knee is still healing (hence the grimace)!

February 2025 science summary

 Good day,

I have a mixture of papers as usual this week, covering using AI to do lit review (on natural climate solutions), more on seaweed to reduce cattle emissions, one on fire management, and one bad study on return-to-office mandates.

Also, I have no idea how the cost and complexity of this new AI monitoring tool (SPARROW, https://blogs.microsoft.com/on-the-issues/2024/12/18/announcing-sparrow-a-breakthrough-ai-tool-to-measure-and-protect-earths-biodiversity-in-the-most-remote-places/) compares to simpler camera trap setups but I’m especially curious if the acoustic component might be able to detect amphibians or birds unlikely to be visible in a camera trap (thanks to Tara Schnaible for passing this on). If any of you are using camera traps and/or microphones for biomonitoring I'd love to hear your thoughts!

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


CLIMATE CHANGE AND AI METHODS:
Chang et al., 2024 uses specialized large language models to assess evidence for 11 co-impacts (positive or negative) of natural climate solutions (NCS). They extracted data from 257,266 studies (after screening 2.3 million)! Most (87%) focused on management, ~30% covered protection and/or restoration, but <2% mentioned cost or equity or Indigenous peoples or local communities. Fig 2 has a nice breakdown of NCS pathways, biome, co-impacts, etc., and Fig 4b maps countries by both evidence and mitigation potential. Paraguay and Republic of the Congo pop as highest carbon w/ lowest evidence (needing research), while the Americas and E/SE Asia have high evidence and high carbon (needing implementation). Fig 3 shows the volume of evidence for how 22 NCS pathways intersect with the 11 co-impacts (9 of which relate to human well-being). They argue that West and Central Africa deserves special research attention as evidence and human development index are relatively low while NCS potential and threatened species are high. One key caveat: evidence volume does not mean evidence quality. For example, there are many papers on sowing legumes in pasture to reduce enteric methane, but I'm not aware of any that are both accurate and precise enough for implementation (since putting them in the wrong places would lead to increased emissions). But this is still a great example of using AI to review a much larger body of evidence than would be possible manually.


CATTLE AND CLIMATE CHANGE:
Meo-Filho et al. 2024 is an important study (part of a special issue of papers around the sustainability of animal foods and plant alternatives, https://www.pnas.org/topic/561). There's been lots of research with hyperbolic claims about red algae reducing methane production in cattle (mostly in vitro, or tests in a petri dish). I believe this is the first paper to measure methane reductions not only 1) in vivo (a test of what happens in real animals) but 2) in the grazing phase of their life cycle. Most American cattle graze for very roughly 15 months before spending 3 months in a feedlot, and they emit more methane per day when grazing. Only 15% of total cattle production GHGs come from the feedlot phase, so even big reductions then can't touch cattle's high carbon footprint. But this paper found supplementing with the seaweed reduced GHGs relative to control animals by 38% over 90 days with no side effects! That is great news and this is work worth following up, BUT a few key caveats: 1) this was a study of only 24 animals, 2) the animals began at 15 months when they would typically go to a feedlot, to show how much this could really reduce the total carbon footprint of cattle (and if any side effects crop up eventually) it would need to be tested on calves from when they are weaned off of milk to when they go to slaughter, and 3) variations in cattle breed, the dominant type of grass they're eating, and climate could all affect the results. So it's very good news, but does not yet mean it's possible to produce a burger w/ 1/3 less carbon. Also, while the numbers are hotly contested, remember that the carbon footprint of beef is very roughly 10* that of pork or chicken (~50* the GHG of beans), so even if the reduction IS scalable, beef will still be a high carbon food.

Cowley et al. 2024 is a paper with very exiting results about reducing the carbon footprint of beef. They fed Australian Angus cows in a feedlot red seaweed (Asparagopsis) infused into vegetable oil, and added it to their diet at three concentrations of CHBr3 from the sewaweed, plus a control w/ no seaweed (5 cows for each of the four treatments). The medium and high doses reduced enteric methane (CH4) by 98% and 99%, with no significant reported side effects. Other studies have seen less impressive reductions in live cattle (e.g. George et al. 2024 found ~50% reduction), although in petri dishes 99% reductions have been achieved before. The discussion covers potential factors influencing the CH4 reduction, including dose, how much of the feedlot diet is grain vs grass, and cattle breed. Caveat - one high dose cow (20% of the sample) got acidosis and had to be removed, all groups had some health problems, and the medium and high doses did increase neutrophil and platelet count. Overall - at medium and high doses the methane was almost eliminated without affecting meat taste or safety, and without clear cattle health impacts. So the study is very promising, but needs to be replicated with larger groups and different contexts (including eventually a study using Asparagopsis during both the entire grazing phase and feedlot phase).


FIRE MANAGEMENT:
Lacey et al. 2024 highlights opportunities for prescribed fire and/or thinning (removing trees and/or brush) to proactively reduce risk for vulnerable communities and areas of high ecological value. Socially vulnerable communities are less likely to get this preventive fire management, but the authors find there are "win-win" opportunities for places high in: ecological value (specifically biodiversity, connectivity, and climate resilience), ecosystem services (carbon and drinking water), social vulnerability (see Table 1 for indicators), and the potential for wildfire mitigation to be effective (the last is based on fire hazard and vegetative cover). Fig 2c has their top priority areas, including big chunks in the Appalachians, Ozarks, and Rocky Mountains (esp. CO and ID), and Fig 4 shows in yellow where those overlap with the USFS top 10 firesheds. Fig 3 shows how much better their priority areas perform against several indicators than a focus solely in fire mitigation potential; as you'd expect optimizing for social vulnerability, ecosystem services, and ecological value results in sites that score a lot better on those indicators! That may seem obvious, but to reframe: in conservation we OFTEN don't include certain objectives in our planning but still expect to have great stories about all the co-benefits we got anyway. This paper is a great pitch for the value of inclusion; planning for what you care about up front will help you focus work on the places where you can have the most impact.


RETURN TO OFFICE MANDATES:
I already put this on LinkedIn but also wanted to flag here that I thought the recent Ding & Ma 2024 study from University of Pittsburgh (which has had a lot of media attention w/o scrutiny) was misleading. They found that 1) return to office mandates don't improve employee or company performance and 2) these mandates are used more to blame employees and "grab power" than to try and improve performance. This doesn't appear to be peer-reviewed research, which makes me more skeptical by default (it could still be right, but there's no screen for bad methods or misleading results). The paper's tone and methods make it look like they set out to prove some preconceived notions rather than exploring what's going on with an open mind, and the way they assert attribution and causation to some findings they report appear unsupported by the data. Their interpretations of their data are plausible, but even if you trust the data there are other valid interpretations which are also plausible. 

The reason I posted this despite it seeming like a "bad" study is to flag the role of bias in reading science. I believe that if I was required to go to the office more often, it would negatively impact my performance and happiness. I can point to personal experience backing that up (I'm more willing to work longer hours when I don't have a commute or when I'm getting hungry but don't have food nearby to keep working). But in situations like this where I have an opinion and feel inclined to "right on!" what I read, that's exactly when I need to slow down and read carefully since I know I have bias leading me to accept certain results and interpretations as convincing. Also - read a news article about science and wondering if it's misleading? I generally first look for the press release from the host institution (to read a summary that the authors would have had a chance to review to reduce accidental misunderstanding, although they are still unreliable whether on accident or on purpose to hype it: https://business.pitt.edu/return-to-office-mandates-dont-improve-employee-or-company-performance/ ), then read the actual paper.

Don't assume the press release, or even my summary is accurate! Always check before you share or act on a research summary.


REFERENCES:
Chang, C. H., Erbaugh, J. T., Fajardo, P., Lu, L., Molnár, I., Papp, D., Robinson, B. E., Austin, K. G., Castro, M., Cheng, S. H., Cook-Patton, S., Ellis, P. W., Garg, T., Hochard, J. P., Kroeger, T., McDonald, R. I., Poor, E. E., Smart, L. S., Tilman, A. R., … Masuda, Y. J. (2024). Global evidence of human well-being and biodiversity impacts of natural climate solutions. Nature Sustainability. https://doi.org/10.1038/s41893-024-01454-z

Cowley, F. C., Kinley, R. D., Mackenzie, S. L., Fortes, M. R. S., Palmieri, C., Simanungkalit, G., Almeida, A. K., & Roque, B. M. (2024). Bioactive metabolites of Asparagopsis stabilized in canola oil completely suppress methane emissions in beef cattle fed a feedlot diet. Journal of Animal Science, 102(April). https://doi.org/10.1093/jas/skae109

Ding, Y., & Ma, M. (Shuai). (2024). Return-to-Office Mandates. In S&P Global Market Intelligence. https://doi.org/10.2139/ssrn.4675401

Lacey, L. M., Suraci, J. P., Littlefield, C. E., Busse, B. S., & Dickson, B. G. (2024). Informing proactive wildfire management that benefits vulnerable communities and ecological values. People and Nature, August, 1–15. https://doi.org/10.1002/pan3.10733

Meo-Filho, P., Ramirez-Agudelo, J. F., & Kebreab, E. (2024). Mitigating methane emissions in grazing beef cattle with a seaweed-based feed additive: Implications for climate-smart agriculture. Proceedings of the National Academy of Sciences, 121(50), 2–9. https://doi.org/10.1073/pnas.2410863121


Sincerely,
 
Jon
 
p.s. the photo is of a salt marsh at The Wetlands Institute in Stone Harbor, NJ

Best of 2024 science summaries

Happy New Year,

How better to celebrate the new year than with old science?!

As usual, here are my favorite 15 reruns (article summaries) from 2024, plus a few of my favorite bits about AI since I keep getting requests for more of that:

• Don’t put anything sensitive into AI! Enterprise licenses provide some protection for non-public but not highly sensitive info.
• I loved these tips for better AI prompts to help you get better results: https://www.oneusefulthing.org/p/getting-started-with-ai-good-enough  
• This is a great overview of some really good and really bad use cases for AI: https://www.oneusefulthing.org/p/15-times-to-use-ai-and-5-not-to
• Remember that AI is always changing. As of mid-December, Google Gemini’s NotebookLM not only turns a PDF you upload into an NPR-style podcast, it also now lets you interact w/ the “hosts”!  

Upset at the articles I missed? Please email me your own favorites from 2024 and I'll do what I can to include them in upcoming summaries.

As always people can sign up to receive these summaries at http://bit.ly/sciencejon (no need to email me). On with the reruns!


CLIMATE CHANGE
OK, for years people have been hyping the potential of a kind of seaweed (Asparagopsis) to reduce methane emissions in cattle. But the in vitro evidence was mixed - with potential toxicity and downsides a concern if the dose wasn't just right. George et al 2024 is a live trial with good news! They found methane emissions from cattle given an Asparagopsis additive were cut roughly in half compared to control, with 6.6% higher weight gain per unit of feed and no substantial impacts on quality or health (fat color maybe a bit better, tenderness maybe a bit worse). The methane reduction peaked at day 21 and declined afterwards, but since most cattle are in feedlots only ~3 months (ranging from 1.5-4) the decline after day 100 is pretty moot. That's a lot of potential! The only potential downsides were ~50% higher bromine residues in kidney and muscle (I couldn't quickly find guidance on safe levels). Caveats: 1) there were no conflicts declared but the authors appear to almost all work as feedlot consultants and it's single rather than double-blinded, 2) in the US the feedlot phase is only about 15% of the lifecycle emissions of a cow (and of that, some is from growing crops and nitrous oxide) so TOTAL impact on CO2e / kg beef is not as dramatic. Overall my take is 1) this should absolutely be tested and replicated more - anything that reduces the very high carbon of beef is worth pursuing. BUT 2) if this is marketed as "green beef" or license to avoid reductions, it could be net harmful for the climate. and 3) IF spraying this solution on grass worked similarly and didn't inhibit development of calves, the impact could be much higher (since ~80%ish of a cow's life is grazing prior to feedlot, and methane emissions are higher on grass than feed). So let's test that too (note: there’s a new study claiming a ~1/3 reduction in methane during grazing via seaweed supplements that I haven’t reviewed yet). There's a blog about this at https://www.theguardian.com/australia-news/article/2024/aug/18/feeding-seaweed-supplement-to-cattle-halved-methane-emissions-in-australian-feedlot-study-finds

Trencher et al, 2024 is an analysis of the quality of carbon credits on the voluntary market. They focus on the 20 companies retiring the most credits between 2020-2023 (134 million metric tons CO2e), which is 20% of all global retirements on the three registries (see Fig 1 for company list). They found 87% of credits have a high risk of not providing real additional reductions (6% were low risk, most of the rest was medium), and 97% of credits focused on avoiding emissions rather than removal. Note that they classified all REDD+ (reducing deforestation and/or degradation) as high risk given that they have often 1) overestimated additionality, 2) not stopped deforestation, and/or 3) displaced deforestation elsewhere (aka 'leakage'). They also classify large-scale renewable energy as high-risk, since the price of credits is not typically the decisive factor in those projects (they are often built w/ or w/o credits) and they are often build in countries w strong government support for renewable energy. They also found that companies strongly prefer the cheapest credits (which creates demand for lower-quality offsets) often from older projects, although some companies have paid a lot more for REDD projects. The authors call for more regulation of the voluntary market, and for companies not using voluntary credits to support claims of offsetting emissions.

 
CONSERVATION IMPACT:
Langhammer et al. 2024 is the big splashy new Science paper looking at the global impact of conservation. It's a meta-analysis of trials comparing interventions to counterfactuals (similar areas w/o action). They found conservation helps 2/3 of the time (45% of trials led to absolute improvement in biodiversity, 21% reduced biodiversity loss), but is harmful 1/3 of the time (in 21% of trials biodiversity declined more due to conservation, in 12% it improved less due to conservation), and only 2% of trials showed no difference). That's not a great track record - I'd hoped net harm would be rare (1/3 is very high!), and just over half the time we're losing biodiversity despite trying to stop it. Fig 2 helpfully shows how impact varies by type of intervention: protected areas show the smallest positive effect on average, and invasive species removal shows the largest positive effect. I'd ignore "sustainable use of species" b/c it's a weirdly broad category that somehow only included 4 papers on wildlife hunting and 1 on fishing, although a few fishing papers are included under protected areas (details in the supplement - this makes me think their sample is not representative of conservation broadly). While the authors conclude conservation is working and we should do more of it, I bet if this was a paper on medical efficacy we'd consider interventions that are 2/3 helpful and 1/3 harmful an urgent cry to improve efficacy BEFORE we try to scale work that is so often ineffective or harmful. Would you send your kids to a school where 1/3 of students learned less than kids not in school at all?


EVIDENCE ASSESSMENTS / SCIENTIFIC REPRODUCIBILITY:
Scientists often complain policy makers don't follow our recommendations (or even read them). But Brisco et al. 2023 finds that recommendations from meta-analyses tend to change over time as research continues. They looked at 79 papers (121 meta-analyses) and found that over time 93% of analyses either had a big change in effect size (+- 50% or more, see Fig 2 for examples) or change in statistical significance (see Fig 3). The key results are in Fig 5, which I find pretty confusing. Results staying consistently statistically significant w/ each study is rare, and ~25% of analyses showed a reversal in effect (from positive to negative or vice versa). Those reversals are the change we care the most about since it means action can backfire. BUT if you ignore the studies that were never statistically significant (seems safe) it's only 12% of analyses that flip, and if you also ignore the ones that lost significance (meaning the reversal is less meaningful) it goes down to 11%. That's still pretty bad though - 1 time out of 9 the scientific recommendation might lead to the opposite outcome we intend. They recommend scientists use cumulative meta-analyses to look for trends, and the reminder that we're often wrong reinforces the need for adaptive management and an empirical approach to seeing what works in a given context.
 
 
FIRE:
Pivello et al. 2021 is a good comprehensive overview of wildfire across Brazil. It's long and dense so hard to summarize! Natural fires are most common at the beginning of the wet season when lightning ignites accumulated dry vegetation. Fig 1 has an overview of fire by biome: the Amazon followed by Cerrado have the most fires; the Pantanal and Cerrado typically have the highest % burned (they are both fire-dependent, as is the Pampas, see Fig 2), and in 2020 the Pantanal had roughly triple the % burned and fire density as others. Pollen evidence (from a different study, Power et al. 2016) indicates fire activity in the Pantanal peaked about 12,000 years ago (people have only lived there for about 8,000 years, and grazed cattle for ~250). Introducing cattle has caused a shift from burning every 3-6 years (mostly in the beginning or sometimes end of the wet season) to burning every year or two during a relatively dry part of the wet season (see Fig 6). Conversely, fire suppression in the Cerrado has also driven woody encroachment of savannas. In the Amazon and Atlantic Forest, natural fire is rare and very infrequent, making fire especially harmful as species are not adapted to it. The combination of deforestation and drought make it much easier for fire to spread (and Amazonian deforestation means more drought in the Pantanal). 1/3 of the forest in the Amazon from 2003-2019 were associated w/ deforestation. Indigenous people mostly used fires in small areas, but since European colonization it's used at larger scales to clear land permanently (or alternately suppressed, see Fig 7 for a nice timeline of fire landmarks). Integrated fire management (IFM) is uncommon (except a few federal protected areas, mostly in the Cerrado). Only Minas Gerais and Roraima states have IFM laws. The authors recommend: 1) fire management policy should include climate mitigation and poverty reduction to reduce fire risk; 2) better fire monitoring and management systems; 3) filling knowledge gaps around drivers of fire, how fire impacts wetlands, human dimensions of fire, impacts of different fire regimes on grazing productivity and carbon; 4) better enforcement of illegal fire use (including more resources); 5) including local communities in developing fire management plans, and 6) national and state level fire policies with adequate resources for implementation (including data collection and sharing, and clear and simple rules about fire use).
 
Balch et al. 2024 found that over the last 20 years fires in the US have been spreading faster. In the Western US over 20 years the average peak daily growth rate (the average of the fastest each fire grew on a given day) increased 2.5 times (in California they increased by 4 times). The fastest 3% of fires nationally (spreading more than 1,620 ha in a day) destroyed between 78-89% of the buildings lost to fire (the paper lists each number in different section for the same stat). I’ve heard a lot more about severity and frequency and extent of fire, but thinking about speed is also important as faster fires are harder to respond do, and may make really smooth coordination increasingly important. Increases in drought conditions and potential increases in high winds could make this worse over time. 


FRESHWATER:
Flitcroft et al. 2023 notes that counting effective freshwater protection globally is really hard (as is getting effective protection to happen). Fig 1 has a nice summary of how restrictive different protection mechanisms are. They also call for both better management of existing protected areas (PAs) to include freshwater conservation needs, and protections for freshwater in new places. While issues around data resolution and data availability continue to pose challenges to freshwater conservation, they argue that more explicit consideration of both freshwater and terrestrial objectives in any area-based protection is a good start.
 
Jasechko et al. 2024 is a global assessment of groundwater levels since 2000 (using 170,000 wells and 1,700 aquifers) and comparing them to earlier trends for ~1/3 of those aquifers. They found 36% of aquifers were drying up (water level dropping deeper by 0.1 m / yr or more), and 6% of aquifers were improving (water level rising 0.1 m / yr or more), w/ 58% of aquifers not changing quickly in this century. 30% of the aquifers where they had 40 years of data declined faster in the 21st century than the 20 years prior (see Fig 3), but in 49% of those aquifers declines slowed or reversed. Unsurprisingly the trend is worst in drylands w/ farmland, and groundwater deepening is globally correlated w/ low precipitation, high evapotranspiration, and extent of agriculture. See Fig 1 and 2 for global map of trends, highlighting hotspots of decline in CA, the US high plains, Iran, India, central Chile, and a few others. There's a news article about the study at https://www.cnn.com/2024/01/24/climate/groundwater-global-study-scn/index.html

Wang et al. 2024 looks at how climate change has changed the seasonality of river flow (how much it varies month to month, including frequency of droughts and floods). They found that ~14% of long-term river gauges show changes in seasonality over the last 50 years that isn't driven by changing annual precipitation. The surprise is that seasonality is mostly DECREASING counter to the narrative of more floods and droughts (see Fig 1 for a map of results, and Fig 2 which adds detail). In their figures brown means less seasonality (more even flow): "L+" means low flows become higher flows (NOT higher frequency of drought) while "H-" means floods see lower flood volume (again NOT lower frequency of flood events). You'll see most of North America, most of Europe, and some of Russia have seen reduced seasonality in recent decades. Blue means MORE seasonality, focused in: SE Brazil, some European countries, and in the US the SE and some of the Rocky Mountains. The explanation is worth reading in full, but in brief: 1) snow melting earlier means less runoff from snow at the same time as spring rains, 2) early spring greening means more water gets transpired, 3) it's more complicated in places not dominated by snowmelt.
 

HORIZON SCANNING / EMERGING ISSUES:
I realized I've only rarely reviewed Bill Sutherland's annual "horizon scan" article listing 15 emerging conservation issues that potentially deserve to be better-known. Last year (I just read the 2024 version a year late) they used artificial intelligence to generate some of the ideas but none made the cut. Here's the final list so you can decide if any are worth looking up (and here’s the brand new 2025 paper if you want to catch up):
1. New sources of hydrogen for energy (mining or electrolysis instead of natural gas),
2. Decarbonized ammonia (making fertilizer w/ lower carbon emissions but could increase fertilizer wasted),
3. Feeding people and/or animals w/ cultivated bacteria,
4. Light-free artificial photosynthesis (yes, it's as weird as it sounds) for indoor ag,
5. Enhanced rock weathering at scale (putting rock dust on croplands to sequester carbon),
6. Potential global declines in earthworm populations (more data is needed to see if UK decline is representative),
7. Ecoacoustics to monitor soil ecology (testing how meaningful soil sounds are for estimating things like biodiversity and water flow),
8. Wildfire affecting El Niño and La Niña phase (aerosols leading to the La Niña phase),
9. Benchtop DNA printers (potential to eventually allow guerilla genetic engineering),
10. Better predicting chemical toxicity from early data,
11. a skyscraper city planned in Saudi Arabia that birds could crash into when migrating from Europe to Africa.,
12. Sea urchin die-offs (possibly from disease) leading to algal overgrowth on corals and other marine ecosystems,
13. Ocean-based carbon removal (from the air or dissolved in water to stable forms),
14. Warming "twilight zones" (200-1000m below sea surface) affecting global nutrient and carbon cycles, and
15. Melting Antarctic ice changing deep sea currents.


MAMMALS:
Greenspoon et. al 2023 is an attempt to estimate the biomass of all wild mammals on earth (combined), arriving at 60 Mt total: 20 Mt (million metric tons) on land (half from "even-hoofed" mammals, see FIg 2), and 40 Mt in oceans (23 Mt of which comes from baleen whales). But the kicker is that they estimate human biomass at 390 Mt, and livestock biomass at 630 Mt (420 Mt from cattle: which is more than all humans plus all wild land mammals). Fig 4 awkwardly tries to compare all mammal biomass on earth, showing how wild species have been squeezed. The wild mammal estimates mostly come from the IUCN red list which skews towards expert assessments of more threatened spp., and the numbers won't be "right" for several reasons (these estimates are hard, and the data are highly limiting). But it seems solid that humans and livestock substantially outweigh wild mammals.
There's a good critique of the paper (arguing that Greenspoon et al. underestimate biomass by a factor of 5.5) by Santini et al. here https://www.pnas.org/doi/10.1073/pnas.2308958121 and a reply from the Greenspoon authors pointing out why the methods used in the critique are also (differently) flawed: https://www.pnas.org/doi/10.1073/pnas.2316314121
 

MIGRATORY SPECIES / WILDLIFE CONNECTIVITY:
The new State of the World's Migratory Species report (UNEP-WCMC 2024) has an update on how the 1,189 migratory species in CMS are doing. Almost half (44%) are in decline (with 22% at risk of extinction, including 97% of listed fish spp), 1/3 are stable, and the rest are split between improving and unknown. The report also notes that 399 spp not even listed in CMS (including ~200 fish spp, ~150 bird spp, and ) are at risk (from critically endangered to near threatened). See Fig 2.10b for an overview of which migratory species CMS leaves out (including horseshoe crabs!) and 2.10c for the subset at risk. Unsurprisingly the main threats are habitat loss (along w/ degradation and fragmentation) and overexploitation (hunting and fishing). Recommendations on page ix-xi are familiar and unsurprising (albeit important). There's a blog about this paper with key highlights at: https://www.unep.org/news-and-stories/press-release/landmark-un-report-worlds-migratory-species-animals-are-decline-and
 
Littlefield et al. 2024 (I'm a minor author) examines how wildlife road crossings can be beneficial to help species adapt to climate change. We recommend that when siting crossings we should consider a) current wildlife movements, AND expected short-term and long-term shifts in species range and migrations due to b) climate change AND c) human land use change (expansion of housing, ag, etc.). We show how doing this was accomplished for elk in Colorado.
For this to work well, diversion fencing is important to channel wildlife to crossings, and avoiding future fragmentation is key. The paper is open access. There's a press release for the paper here: https://fish.freeshell.org/publications/Littlefield2024-PressRelease.pdf


POLLINATORS:
Li et al. 2024 is a methods paper about using land cover data to predict floral resource availability for pollinators. I'm an author despite minimal input; the lead author based this on work by the last author, who I provided some guidance to when he was a postdoc. There are a few potentially interesting things in here. 1) Most pollinators don't make much honey, so their populations are limited by the time of year w/ the least food available (pollen and nectar). The methods here help you figure out those bottlenecks if you want to target habitat restoration to boost pollinator populations. 2) Plants vary a lot in how much nectar and pollen they make. Not every crop makes flowers that feed pollinators (likely obvious, but some crops and cover crops are harvested or terminated before flowering, and wind-pollinated plants don't have nectar). Trees produce a ton of nectar and pollen. 3) The paper looked at two different ways to map land cover, and surprisingly the simpler approach worked as well (similar error levels)! It's a good reminder to always question whether you need more complexity and accuracy. If you just have a garden and want more bees and other pollinators, this blog post I wrote may help: https://sciencejon.blogspot.com/2024/05/new-paper-on-mapping-pollinator.html
 

WETLANDS:
The latest report on the status of wetlands in the US (excluding AK and HI) is a bummer but has some useful info. Key summaries are in Fig 9 and Table 2, but in short on net 221,000 acres of wetlands were converted, mostly to ag and tree plantations followed by housing developments. But that net change hides that fact that we actually lost 670,000 acres of vegetated wetlands, with non-vegetated wetlands like ponds, sandbars, and mudflats increasing (but NOT providing nearly as much ecological value). The report calls for more coordination to achieve no net loss of wetlands, to update and improve the National Wetlands Inventory, develop and implement better wetland conservation and management (duh), and commit to long-term monitoring and adaptive management.


REFERENCES:

Balch, J. K., Iglesias, V., Mahood, A. L., Cook, M. C., Amaral, C., DeCastro, A., Leyk, S., McIntosh, T. L., Nagy, R. C., St. Denis, L., Tuff, T., Verleye, E., Williams, A. P., & Kolden, C. A. (2024). The fastest-growing and most destructive fires in the US (2001 to 2020). Science, 386(6720), 425–431. https://doi.org/10.1126/science.adk5737
 
Brisco, E., Kulinskaya, E., & Koricheva, J. (2023). Assessment of temporal instability in the applied ecology and conservation evidence base. Research Synthesis Methods, November, 1–15. https://doi.org/10.1002/jrsm.1691
 
Flitcroft, R. L., Abell, R., Harrison, I., Arismendi, I., & Penaluna, B. E. (2023). Making global targets local for freshwater protection. Nature Sustainability. https://doi.org/10.1038/s41893-023-01193-7
 
George, M. M., Platts, S. V., Berry, B. A., Miller, M. F., Carlock, A. M., Horton, T. M., & George, M. H. (2024). Effect of SeaFeed, a canola oil infused with Asparagopsis armata , on methane emissions, animal health, performance, and carcass characteristics of Angus feedlot cattle. Translational Animal Science, 8(August). https://doi.org/10.1093/tas/txae116
 
Greenspoon, L., Krieger, E., Sender, R., Rosenberg, Y., Bar-On, Y. M., Moran, U., Antman, T., Meiri, S., Roll, U., Noor, E., & Milo, R. (2023). The global biomass of wild mammals. Proceedings of the National Academy of Sciences, 120(10), 2017. https://doi.org/10.1073/pnas.2204892120

REPLY AND COUNTER-REPLY TO GREENSPOON:

• Santini, L., Berzaghi, F., & Benítez-López, A. (2024). Total population reports are ill-suited for global biomass estimation of wild animals. Proceedings of the National Academy of Sciences, 121(4), 1–3. https://doi.org/10.1073/pnas.2308958121   
• Greenspoon, L., Rosenberg, Y., Meiri, S., Roll, U., Noor, E., & Milo, R. (2024). Reply to Santini et al.: Total population reports are necessary for global biomass estimation of wild mammals. Proceedings of the National Academy of Sciences of the United States of America, 121(4), 1–2. https://doi.org/10.1073/pnas.2316314121

Jasechko, S., Seybold, H., Perrone, D., Fan, Y., Shamsudduha, M., Taylor, R. G., Fallatah, O., & Kirchner, J. W. (2024). Rapid groundwater decline and some cases of recovery in aquifers globally. Nature, 625(7996), 715–721. https://doi.org/10.1038/s41586-023-06879-8
 
Lang, M. W., Ingebritsen, J. C., & Griffin, R. K. (2024). Status and Trends of Wetlands in the Conterminous United States 2009 to 2019. U.S. Department of the Interior; Fish and Wildlife Service, Washington, D.C. 43 pp. https://www.fws.gov/project/2019-wetlands-status-and-trends-report

Langhammer, P. F., Bull, J. W., Bicknell, J. E., Oakley, J. L., Brown, M. H., Bruford, M. W., Butchart, S. H. M., Carr, J. A., Church, D., Cooney, R., Cutajar, S., Foden, W., Foster, M. N., Gascon, C., Geldmann, J., Genovesi, P., Hoffmann, M., Howard-McCombe, J., Lewis, T., … Brooks, T. M. (2024). The positive impact of conservation action. Science, 384(6694), 453–458. https://doi.org/10.1126/science.adj6598

Li, K., Fisher, J., Power, A., & Iverson, A. (2024). A map of pollinator floral resource habitats in the agricultural landscape of Central New York. One Ecosystem, 9. https://doi.org/10.3897/oneeco.9.e118634
 
Littlefield, C. E., Suraci, J. P., Kintsch, J., Callahan, R., Cramer, P., Cross, M. S., Dickson, B. G., Duncan, L. A., Fisher, J. R., Freeman, P. T., Seidler, R., Wearn, A., Andrews, K. M., Brocki, M., Dodd, N., Gagnon, J., Johnson, A., Krosby, M., Skroch, M., & Sutherland, R. (2024). Evaluating and elevating the role of wildlife road crossings in climate adaptation. Frontiers in Ecology and the Environment, 1–10. https://doi.org/10.1002/fee.2816
 
Pivello, V. R., Vieira, I., Christianini, A. V., Ribeiro, D. B., da Silva Menezes, L., Berlinck, C. N., Melo, F. P. L., Marengo, J. A., Tornquist, C. G., Tomas, W. M., & Overbeck, G. E. (2021). Understanding Brazil’s catastrophic fires: Causes, consequences and policy needed to prevent future tragedies. Perspectives in Ecology and Conservation, 19(3), 233–255. https://doi.org/10.1016/j.pecon.2021.06.005
 
Sutherland, W. J., Bennett, C., Brotherton, P. N. M., Butchart, S. H. M., Butterworth, H. M., Clarke, S. J., Esmail, N., Fleishman, E., Gaston, K. J., Herbert-Read, J. E., Hughes, A. C., James, J., Kaartokallio, H., Le Roux, X., Lickorish, F. A., Newport, S., Palardy, J. E., Pearce-Higgins, J. W., Peck, L. S., … Thornton, A. (2024). A horizon scan of global biological conservation issues for 2024. Trends in Ecology & Evolution, 39(1), 89–100. https://doi.org/10.1016/j.tree.2023.11.001
 
Trencher, G., Nick, S., Carlson, J., & Johnson, M. (2024). Demand for low-quality offsets by major companies undermines climate integrity of the voluntary carbon market. Nature Communications, 15(1), 6863. https://doi.org/10.1038/s41467-024-51151-w
 
UNEP-WCMC, 2024. State of the World’s Migratory Species. UNEP-WCMC, Cambridge, United Kingdom.
https://www.cms.int/en/publication/state-worlds-migratory-species-report
 
Wang, H., Liu, J., Klaar, M., Chen, A., Gudmundsson, L., & Holden, J. (2024). Anthropogenic climate change has influenced global river flow seasonality. Science, 383(6686), 1009–1014. https://doi.org/10.1126/science.adi9501


Sincerely,
 
Jon
 
p.s. I inherited that Christmas sweater from my dad, and typically only pull it out once a year for a Christmas sing-along

December 2024 science summary

Congratulations,

If you're reading this you made it to December! I've got four unrelated reviews this month; the first is a new paper about wildlife road crossings to promote climate adaptation (I'm a minor author).

Also - this is a great piece on how to get better at using AI: https://www.oneusefulthing.org/p/getting-started-with-ai-good-enough The short version is: don't treat AI like a search engine! Give it more context and instructions and let it figure out precisely what you want through iteration. The author says it probably takes ~10 hrs of experimentation to get good enough at using AI for it to be working well.

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


WILDLIFE CONNECTIVITY & CLIMATE ADAPTATION:
Littlefield et al. 2024 (I'm a minor author) examines how wildlife road crossings can be beneficial to help species adapt to climate change. We recommend that when siting crossings we should consider a) current wildlife movements, AND expected short-term and long-term shifts in species range and migrations due to b) climate change AND c) human land use change (expansion of housing, ag, etc.). We show how doing this was accomplished for elk in Colorado.
For this to work well, diversion fencing is important to channel wildlife to crossings, and avoiding future fragmentation is key. The paper is open access. There's a press release for the paper here: https://fish.freeshell.org/publications/Littlefield2024-PressRelease.pdf


HORIZON SCANNING / EMERGING ISSUES:
I realized I've only rarely reviewed Bill Sutherland's annual "horizon scan" article listing 15 emerging conservation issues that potentially deserve to be better-known.This year they used artificial intelligence to generate some of the ideas but none made the cut. Here's the final list so you can decide if any are worth looking up:
1. New sources of hydrogen for energy (mining or electrolysis instead of natural gas),
2. Decarbonized ammonia (making fertilizer w/ lower carbon emissions but could increase fertilizer wasted),
3. Feeding people and/or animals w/ cultivated bacteria,
4. Light-free artificial photosynthesis (yes, it's as weird as it sounds) for indoor ag,
5. Enhanced rock weathering at scale (putting rock dust on croplands to sequester carbon),
6. Potential global declines in earthworm populations (more data is needed to see if UK decline is representative),
7. Ecoacoustics to monitor soil ecology (testing how meaningful soil sounds are for estimating things like biodiversity and water flow),
8. Wildfire affecting El Niño and La Niña phase (aerosols leading to the La Niña phase),
9. Benchtop DNA printers (potential to eventually allow guerilla genetic engineering),
10. Better predicting chemical toxicity from early data,
11. a skyscraper city planned in Saudi Arabia that birds could crash into when migrating from Europe to Africa.,
12. Sea urchin die-offs (possibly from disease) leading to algal overgrowth on corals and other marine ecosystems,
13. Ocean-based carbon removal (from the air or dissolved in water to stable forms),
14. Warming "twilight zones" (200-1000m below sea surface) affecting global nutrient and carbon cycles, and
15. Melting Antarctic ice changing deep sea currents.


RIVERS:
Brinkerhoff et al. 2024 (summarized by Harvey & Kampf 2024) asks how much rivers in the continental US originate from ephemeral streams (which rely on rain to flow, as they are always disconnected from groundwater, see Fig 1). The answer is 55% by total streamflow and 59% by total stream length- which may seem surprisingly high at first (and they have a few reasons it's likely an underestimate)! But it makes sense; streams have to start SOMEwhere, and that's either rain or groundwater or a mix. If it's rain those source headwater streams would dry out faster than bigger downstream reaches. Smaller streams and the West are more reliant on ephemeral streams (where they are dry more often), and the Great Lakes region and Florida are the least dependent on ephemeral flow. The paper notes that since they found the majority of river water comes from ephemeral streams, excluding those streams from the Clean Water Act (due to the Sackett ruling) makes it much harder to regulate water quality overall.


FIRE:
Balch et al. 2024 found that over the last 20 years fires in the US have been spreading faster. In the Western US over 20 years the average peak daily growth rate (the average of the fastest each fire grew on a given day) increased 2.5 times (in California they increased by 4 times). The fastest 3% of fires nationally (spreading more than 1,620 ha in a day) destroyed between 78-89% of the buildings lost to fire (the paper lists each number in different section for the same stat). I’ve heard a lot more about severity and frequency and extent of fire, but thinking about speed is also important as faster fires are harder to respond do, and may make really smooth coordination increasingly important. Increases in drought conditions and potential increases in high winds could make this worse over time. 


REFERENCES:
Balch, J. K., Iglesias, V., Mahood, A. L., Cook, M. C., Amaral, C., DeCastro, A., Leyk, S., McIntosh, T. L., Nagy, R. C., St. Denis, L., Tuff, T., Verleye, E., Williams, A. P., & Kolden, C. A. (2024). The fastest-growing and most destructive fires in the US (2001 to 2020). Science, 386(6720), 425–431. https://doi.org/10.1126/science.adk5737

Brinkerhoff, C. B., Gleason, C. J., Kotchen, M. J., Kysar, D. A., & Raymond, P. A. (2024). Ephemeral stream water contributions to United States drainage networks. Science, 384(6703), 1476–1482. https://doi.org/10.1126/science.adg9430

Harvey, J. W., & Kampf, S. K. (2024). The transitory origins of rivers. Science, 384(6703), 1402–1403. https://doi.org/10.1126/science.adq1714

Littlefield, C. E., Suraci, J. P., Kintsch, J., Callahan, R., Cramer, P., Cross, M. S., Dickson, B. G., Duncan, L. A., Fisher, J. R., Freeman, P. T., Seidler, R., Wearn, A., Andrews, K. M., Brocki, M., Dodd, N., Gagnon, J., Johnson, A., Krosby, M., Skroch, M., & Sutherland, R. (2024). Evaluating and elevating the role of wildlife road crossings in climate adaptation. Frontiers in Ecology and the Environment, 1–10. https://doi.org/10.1002/fee.2816

Sutherland, W. J., Bennett, C., Brotherton, P. N. M., Butchart, S. H. M., Butterworth, H. M., Clarke, S. J., Esmail, N., Fleishman, E., Gaston, K. J., Herbert-Read, J. E., Hughes, A. C., James, J., Kaartokallio, H., Le Roux, X., Lickorish, F. A., Newport, S., Palardy, J. E., Pearce-Higgins, J. W., Peck, L. S., … Thornton, A. (2024). A horizon scan of global biological conservation issues for 2024. Trends in Ecology & Evolution, 39(1), 89–100. https://doi.org/10.1016/j.tree.2023.11.001


Sincerely,
 
Jon
 
p.s. The photo is of my neighbor Buddy's old house; the new owners are adding more levels to it but so far have just removed the roof and back and people who walk by are always surprised to see it.

November 2024 science summary

Howdy,

I've got summaries of articles on carbon credits, wetlands and climate mitigation, and the Pantanal (drought, fire, and habitat loss).

But first - two quick notes on the use of artificial intelligence (AI):

1. When I mention AI tools I should say this every time: a) assume that any information you put into an AI may be shared in ways you don't want, so never put in sensitive / non-public information. b) that also means be wary of putting in copyrighted materials! Some publishers like Elsevier and New York Times have a blanket ban on using their publications in AI tools, and others allow some uses but not others!
2. I'm continuing to find Elicit a really helpful tool to find and summarize or extract info from science papers. If you have questions or want to chat about it let me know. If you register for a free account I can send you links to my custom notebooks to show how some cool features work.

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

CARBON CREDITS
Trencher et al, 2024 is an analysis of the quality of credits on the voluntary carbon market. They focus on the 20 companies retiring the most credits between 2020-2023 (134 million metric tons CO2e), which is 20% of all global retirements on the three registries (see Fig 1 for company list). They found 87% of credits have a high risk of not providing real additional reductions (6% were low risk, most of the rest was medium), and 97% of credits focused on avoiding emissions rather than removal. Note that they classified all REDD+ (reducing deforestation and/or degradation) as high risk given that they have often 1) overestimated additionality, 2) not stopped deforestation, and/or 3) displaced deforestation elsewhere (aka 'leakage'). They also classify large-scale renewable energy as high-risk, since the price of credits is not typically the decisive factor in those projects (they are often built w/ or w/o credits) and they are often build in countries w strong government support for renewable energy. They also found that companies strongly prefer the cheapest credits (which creates demand for lower-quality offsets) often from older projects, although some companies have paid a lot more for REDD projects. The authors call for more regulation of the voluntary market, and for companies not using voluntary credits to support claims of offsetting emissions.

Blanchard et al. 2024 is a short opinion piece arguing that to fund nature conservation, we should pivot from an "offset" model (where companies buy credits to support assertions of lower net emissions and/or being carbon neutral) to a "contributions" model (where the financial contributions are recognized, but not taken as equivalent to reducing gross emissions). The authors say that 1) all entities should prioritize their own direct emissions reduction before seeking to pay others to do that, 2) we need to use the best science to pick what investments are most likely to lead to durable climate mitigation (considering reversibility, other GHGs, albedo, etc.), and 3) independent scientists should audit any quantitative claims made about the benefits of contributions to climate mitigation.


WETLANDS AND CLIMATE CHANGE MITIGATION
Arias-Ortiz et al. 2024 estimate how much methane different kinds of marshes in the U.S. emit each year. They found that warm freshwater marshes (>25.6C mean annual high temperature) produce the most methane by far (172 g CH4/m2/yr = 48.2 t CO2e / yr), followed by other freshwater marshes at low or medium elevation (producing ~1/3 that on average). Across all marshes the average is much lower (26 g CH4/m2/yr = 7.3 t CO2e / yr), and saltier marshes emit less methane. They report mangroves emit roughly twice as much methane flux as marshes, but seagrasses only emit 10% as much as marshes. Predicted methane was really close to measured methane (at least once they calibrated their estimates)


PANTANAL:
Marengo et al. 2021 is a review of the severe drought in the Pantanal in 2019 and 2020. The key direct cause was less warm humid air coming from Amazonia leading to much less rain across the Paraguay river basin, which in turn led to very low water levels in rivers and other wetlands, which reduced shipping goods by river (and economic losses) and enabled widespread fires. Previous studies looking at Pantanal rainfall trends have found only a small overall decrease but with a lot more variation each year. There are more days with no rain, the dry season has gotten drier, the Ládario river has been dropping ~3 cm / yr for 30 years, but the flooding in 2018 was unusually extensive. Part of the issue may be that the Pantanal has been relatively wet since roughly 1970, making a return to severe droughts that have not been seen for decades feel more unusual (see Fig 3). El Niño does not seem to be a driver of drought, nor do various climatic indices correlate well w/ drought years. But in 2019-2020 a strong South Atlantic Convergence Zone caused a shift in dominant winds to the Pantanal coming from drier and colder higher-latitude air.

Guerra et al. 2020 looked at the drivers of predicted habitat conversion in the Upper Paraguay River Basin (including the Pantanal, some of the Cerrado, and a bit of the Amazon) between 2008-2016 (broken into four 2-year periods). Key drivers in the Pantanal were unprotected status and existing land cover, with much weaker impact from elevation (higher means more loss), and in half the time periods there was also an influence of distance to roads (closer means more loss) and cattle (presence leading to more loss). Oddly there was LESS conversion near annual cropland which is very unusual except in dense fully converted ag landscapes. They only saw more habitat loss on land with good ag potential near rivers in the Pantanal from 2010-2012, which could be related to cropland moving closer to water due to the 2012 drought. Note that this model assumes deforestation expands from where it has already happened, rather than modeling other factors (economic, population modeling, commodity prices, planned roads, etc.) to look for what might change in the future.

Martins et al. 2024 recommend priority areas for fire prevention and/or restoration in the Upper Paraguay River Basin, based on the number of fire-sensitive species present (along w/ factors like fire frequency and intensity, dry biomass, and time since the last burn). The relatively few top priority areas for fire management are in red on Fig 2, and occur in a triangle roughly between Paiaguás, Aquidauana, and Bodoquena. There are many more areas flagged as a priority for restoration, but their top focus is 1,206 km2 of forest high in both resilience and sensitive species. But they also note ~6,000 km2 of potential restoration priorities that hadn't been burnt until recently (2019-2022, Fig 5). The supplement also maps the most important places for fire prevention (Supplementary Fig 15).


REFERENCES:

Arias-Ortiz, A., Wolfe, J., Bridgham, S. D., Knox, S., McNicol, G., Needelman, B. A., Shahan, J., Stuart-Haëntjens, E. J., Windham-Myers, L., Oikawa, P. Y., Baldocchi, D. D., Caplan, J. S., Capooci, M., Czapla, K. M., Derby, R. K., Diefenderfer, H. L., Forbrich, I., Groseclose, G., Keller, J. K., … Holmquist, J. R. (2024). Methane fluxes in tidal marshes of the conterminous United States. Global Change Biology, 30(9). https://doi.org/10.1111/gcb.17462

Blanchard, L., Haya, B. K., Anderson, C., Badgley, G., Cullenward, D., Gao, P., Goulden, M. L., Holm, J. A., Novick, K. A., Trugman, A. T., Wang, J. A., Williams, C. A., Wu, C., Yang, L., & Anderegg, W. R. L. (2024). Funding forests’ climate potential without carbon offsets. One Earth, 7(7), 1147–1150. https://doi.org/10.1016/j.oneear.2024.06.006

Guerra, A., Roque, F. de O., Garcia, L. C., Ochao-Quintero, J. M. O., Oliveira, P. T. S. de, Guariento, R. D., & Rosa, I. M. D. (2020). Drivers and projections of vegetation loss in the Pantanal and surrounding ecosystems. Land Use Policy, 91(April 2020). https://doi.org/10.1016/j.landusepol.2019.104388

Martins, P. I., Belém, L. B. C., Peluso, L. M., Szabo, J. K., Trindade, W. C. F., Pott, A., Junior, G. A. D., Jimenez, D., Marques, R., Peterson, A. T., Libonati, R., & Garcia, L. C. (2024). Fire-sensitive and threatened plants in the Upper Paraguay River Basin, Brazil: Identifying priority areas for Integrated Fire Management and ecological restoration. Ecological Engineering, 209(1), 107411. https://doi.org/10.1016/j.ecoleng.2024.107411

Marengo, J. A., Cunha, A. P., Cuartas, L. A., Deusdará Leal, K. R., Broedel, E., Seluchi, M. E., Michelin, C. M., De Praga Baião, C. F., Chuchón Angulo, E., Almeida, E. K., Kazmierczak, M. L., Mateus, N. P. A., Silva, R. C., & Bender, F. (2021). Extreme Drought in the Brazilian Pantanal in 2019–2020: Characterization, Causes, and Impacts. Frontiers in Water, 3(February). https://doi.org/10.3389/frwa.2021.639204

Trencher, G., Nick, S., Carlson, J., & Johnson, M. (2024). Demand for low-quality offsets by major companies undermines climate integrity of the voluntary carbon market. Nature Communications, 15(1), 6863. https://doi.org/10.1038/s41467-024-51151-w

Sincerely,
 
Jon
 
p.s. these are jack o' lantern vegan quesadillas from our Halloween party