Tuesday, July 2, 2024

July 2024 science summary

Baby bunny nibbling a weed


I've just got two science articles this month, but also wanted a plug a book I found really interesting: The Culture Code by Daniel Coyle. There's not a lot of brand new content - he draws heavily on concepts of psychological safety and vulnerability (see Amy Edmondson), learning from failure, how to give effective feedback, ways to generate candor and tough love, making space for feedback, etc.

The reason this one stuck w/ me is that he has pretty compelling real world examples of organizations and leaders that embody some of the recommendations. One of his suggestions was also new to me and really resonates: "resist the temptation to reflexively add value." I've thought before about 1) whether or not my review or input can make something better and how much, and 2) whether I'd add enough value for it to be worth my time. But he notes that 3) every time you weigh in on something, you're missing a chance to express trust in the author and build their confidence that they don't NEED your input for it to be good enough. I'm still grappling with how to put this into practice, but the book is a fast read and I recommend it.

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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

Junk and da Cunha 2012 argue that when ranchers clear trees and shrubs from grazing lands, that should not be equated with deforestation. They note that from the perspective of ranchers, all trees and shrubs within pastures (whether native or not) are "invasive species." It's unusual to use that language to describe the regeneration of trees in what used to be forest (as of ~250 years ago before cattle were introduced) but makes sense from the perspective of someone trying to keep land suitable for cattle (and they note the land was managed for thousands of years to promote other wild game species, making parts of the Pantanal a cultural landscape). Table 1 lists their recommended methods to clear some of the more common woody species. They also discuss how starting in the 1980s, money from a gold rush was used to drive higher-density cattle ranching using African grass species.

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


  • 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

Junk, W. J., & Nunes da Cunha, C. (2012). Pasture clearing from invasive woody plants in the Pantanal: a tool for sustainable management or environmental destruction? Wetlands Ecology and Management, 20(2), 111–122. https://doi.org/10.1007/s11273-011-9246-y

p.s. This is a baby rabbit nibbling a weed in my garden. We had a nest of even tinier ones born more recently, but this guy was the cutest of them all.

Monday, June 3, 2024

June 2024 science summary

Long-horned bee (Melissodes) on sunflower


While I have heard that most of you want me to keep focusing on research articles (and I do have four this month, three on fire and one on pollinators), I also wanted to highlight two great books I've read.

First is "Eve: How the Female Body Drove 200 Million Years of Human Evolution" by Cat Bohannon. The intro has a really incisive indictment of how much biology research has centered on men, and how harmful that's been to both science and women in particular. It then delves into how and why various female traits evolved. I found it both fascinating and useful, and was shocked at how recent and limited efforts to better represent women in clinical trials have been. Here's a NYtimes review:

The other is About Us (https://goodreads.com/book/show/43726545-about-us), which is a collection of articles about many different forms of disability, each written by a person with lived experience (with one exception for people who are mostly unable to communicate, written by an ally). It seems like it would be a slog or a downer, but the articles are short, well-written, and really diverse in style which makes it a pretty quick and fun read (plus super educational). Some are funny, some made me cry (including some funny / sad mixes), but all were worth reading. If you are a New York Times subscriber all the component articles are free, but I liked having it in book form. If you're in DC and want to borrow a copy let me know!

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).

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 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.

I added some tips for improving pollinator habitat in your own garden here.

Parks et al. 2023 looks at severity and frequency of fire in dry conifer forests in the Western US (see Fig 1), comparing the last 40 years to pre-colonial times. They found that forests that kill most or all trees ("stand-replacing fires") are from 3 to 14 times more common now (varying by ecoregion). By looking at areas with varying logging pressures and fire suppression, they show that logging is not reducing stand-replacing fires, but places w/ more prescribed fire and the least fire suppression have much less of these severe fires. For example, in the Gila Wilderness (where many fires are not suppressed) the % of fires that were stand-replacing was 3 times lower than the ecoregion it's in. Prescribed fires consistently led to the lowest stand-replacement, at similar rates to pre-colonial times. Fig 4 and 5 have some great aerial images of forests before and after fire and changes over decades.

Peeler et al. 2023 is an analysis of the best places in 11 US Western states for coniferous forest management (removing small trees and brush, and/or prescribed fire) to reduce the risk of wildfire leading to carbon loss (and/or to protect human communities). Skip to Fig 5 for the key results (the highest ranked places they found) and Fig 3 for more detail. Note that they excluded forests which historically burned rarely b/c ecologically these kinds of forests are supposed to be dense and thinning would alter that ecology (but they still see a role for prescribed fire and tree planting there). They also flag the need for cross-boundary collaboration (including w/ local & Indigenous knowledge and values).

Vidal-Riveros et al. 2023 looks at wildfire history and impacts across the Gran Chaco region (see Fig 1 - it's mostly in Argentina and Paraguay with some in Bolivia and a tiny bit in Brazil, and includes two ecoregions). It's a good review, but they note that the literature has some big gaps. It is mostly focused in Argentina (69% of papers they assessed) with only 10% in Bolivia and 3% in Paraguay. 68% of the papers were on remote sensing of fire frequency, most of which lacked field calibration and validation (which is really important). Unsurprisingly cattle ranching is the main source of wildfire, and in many cases is frequent enough to make it hard for vegetation to recover. For example, in Bolivia 4 yr burning cycles don't allow for forest and soil regeneration, while leaving land fallow for 14-20 years after fire (in Argentina) promotes plant diversity and weed control. The paper has some good info on how different plant species and communities respond to fire. It notes there's limited info on how fire affects invasive non-native plants, but one study in Argentina found prescribed fire killed native and non-native species at similar levels (and some highly flammable non-native spp promote flame spreading). Fig 3 has a nice model of how fire and grazing interact to shape whether grass or trees or shrubs dominate in a given place.

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

Parks, S. A., Holsinger, L. M., Blankenship, K., Dillon, G. K., Goeking, S. A., & Swaty, R. (2023). Contemporary wildfires are more severe compared to the historical reference period in western US dry conifer forests. Forest Ecology and Management, 544(June), 121232. https://doi.org/10.1016/j.foreco.2023.121232

Peeler, J. L., McCauley, L., Metlen, K. L., Woolley, T., Davis, K. T., Robles, M. D., Haugo, R. D., Riley, K. L., Higuera, P. E., Fargione, J. E., Addington, R. N., Bassett, S., Blankenship, K., Case, M. J., Chapman, T. B., Smith, E., Swaty, R., & Welch, N. (2023). Identifying opportunity hot spots for reducing the risk of wildfire-caused carbon loss in western US conifer forests. Environmental Research Letters, 18(9), 094040. https://doi.org/10.1088/1748-9326/acf05a

Vidal-Riveros, C., Souza-Alonso, P., Bravo, S., Laino, R., & Ngo Bieng, M. A. (2023). A review of wildfires effects across the Gran Chaco region. Forest Ecology and Management, 549(September), 121432. https://doi.org/10.1016/j.foreco.2023.121432

p.s. This is a photo of a long-horned bee (Melissodes spp.) which I only ever saw in my garden the one year I grew a couple sunflowers. They look even cooler close up: photo 1photo 2, photo 3

Monday, May 20, 2024

Pollinators - new paper and tips for your garden

Bumblebee on blueberry flowers

I wanted to announce a new paper I've been kindly included as an author on (despite minimal contributions) - Li et al. 2024. It's a methods paper about using land cover data to predict floral resource availability for pollinators. 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 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. https://oneecosystem.pensoft.net/article/118634/

I was asked "How can we use these insights in NYC if at all for urban pollinator husbandry?" which made me realize I should have been more clear about tips for people who want their gardens to better support pollinators.

The actual results are specific to upstate New York and wouldn't apply elsewhere. To make this work one of the authors had to visit many places to see what plants were blooming in what kinds of habitat at different times, then use remote sensing to make a land cover map, then do the math to see when floral resources are scarce.BUT here's how I have been using the very rough concept it in my own garden!

1. Take notes and photos throughout the year as you walk around your neighborhood. When do you first see bees (and/or other pollinators like flies and beetles), and what flowers are they visiting? If you're not seeing bees in your garden - try planting those early bloomers in your own yard.

2. What weeks do you notice the most and least flowers? This isn't a perfect proxy since some flowers have big petals but don't provide much food (like marigolds, geraniums, lilies, and tulips). But it's a start. Write down the weeks where you see the fewest flowers in the neighborhood. That tells you where your garden can have the most added value.

3. Are there certain plants absolutely mobbed with pollinators certain weeks (bees, flies, moths, etc.)? That's a good clue they may be offering food when it's scarce, and/or it's high quality, and you could plant more of them. If you want diverse pollinators, include some plants with small composite flowers (I find those are the most popular overall, especially for sweat bees and bomber flies, something like anise hyssop / Agastache or goldenrod) and some with bigger flowers larger bees like (Penstemon is a favorite of my bees, although the bees also love basil flowers).

4. Based on your notes, add perennial plants that flower when there are the fewest available flowers in the neighborhood. For me that was early spring, late fall, and mid to late summer. Consider also adding some plants that flower intermittently year round like rosemary - it's consistently a star performer in late winter / early spring for me, but also gets some love in the summer. For folks in the DC area my top performers are probably penstemon, anise hyssop, goldenrod, swamp milkweed, and obedient plant (for late fall / early winter)

5. Take notes and/or photos of what you see in your garden. It's fun to see how specific flowers will attract species that won't come otherwise. Use Google Lens or iNaturalist to identify at least the rough kinds of bees. Look for the metallic green or orange Agopostemon bees, get close photos of sweat bees, and whatever other ones surprise you. Here are my pics of pollinators in my garden.

6. Experiment! One year I planted sunflower and it was the only time I saw a long-horned bee in my garden (check out the pics: it's a pretty cool bee). I used to have some lambs ear which I got rid of b/c it wasn't native, but then I stopped seeing carder bees (which collected its fuzz).

7. Leave the dead flower stems through the winter; when new shoots and leaves form on the plant, break off the stems at different heights and toss them elsewhere in your garden (not compost). Many bees and other pollinators lay their eggs in the stems and you don't want to get rid of them before they hatch. See this guide from Xerces for more.

8. Have fun. It's really cool to see how much impact you can have on your garden and neighborhood.

9. Don't forget about habitat for other wildlife! My favorites: 

a) add a birdbath if you're able to commit to dumping and replacing the water daily (you can use rain barrel water like I do). Scrub it with a brush weekly. Get one w/ rough iron sides or leave in a stick so bugs can drink but escape if they fall in.

b) make sure you have some bushes for birds to hang out in. Mine love the swamp dogwood and viburnum more than the inkberries I planted specifically for birds.

c) if you're in the Mid-Atlantic, plant cut-leaf coneflowers. You get 7-8' tall plants that attract so many goldfinches that eat the seeds!

d) let some of your herbs flower. In addition to bees loving basil, cardinals love coriander seeds from cilantro!

e) pokeweed is a native aggressive perennial that provides so much free bird food, especially to catbirds but also robins and mockingbirds and sometimes other species. Cut it back or dig it up when it spreads too much.

e) if you have room, make a brush pile from any pokeweed stems and woody stems and bush trimmings. Several species appreciate them.

f) I used to think "certified wildlife friendly" signs were silly and bragging, but then I heard some neighbors walk by complaining about how unruly my garden was (they didn't see me on the porch). I ordered a sign, and a week or so after I put it up, I heard the same neighbors walk by, see the sign, and say "oh that's cool! it's a wildlife-friendly garden!" So it's worth looking into and the process has a few more tips.

Wednesday, May 1, 2024

May 2024 science summary

Blackwater River trail


This month I have a mixed bag of four unrelated articles: the efficacy of conservation globally, the state of wetlands in the US, the state of the world's migratory species, and one on how biodiversity relates to productivity in forests.

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).

Langhammer et al. 2024 is the big splashy new Science paper looking at the 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?

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.

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

At first I thought Liu et al. 2024 was saying that productivity (the rate at which biomass is created) is a great predictor of forest species richness / biodiversity. That's not right though! Look at Fig 2 - they're actually saying that to predict productivity there is a significant but weak positive correlation to tree species richness, which is about the same as the correlation w/ more compelx metrics (functional attribute diversity and phylogenetic diversity). But forest stands under 30 show lower productivity with higher richness, and wildlife richness is left out entirely. So this is less of a strong & clear relationship, and more of a "if you're going to compare the two you may as well use the simpler metric" result.


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

Liu, Y., Hogan, J. A., Lichstein, J. W., Guralnick, R. P., Soltis, D. E., Soltis, P. S., & Scheiner, S. M. (2024). Biodiversity and productivity in eastern US forests. Proceedings of the National Academy of Sciences, 121(14), 2017. https://doi.org/10.1073/pnas.2314231121

UNEP-WCMC, 2024. State of the World’s Migratory Species. UNEP-WCMC, Cambridge, United Kingdom.


p.s. This photo is on the Blackwater River Trail in the Canaan Valley Resort State Park, where we were treated to some April snow on vacation!

Monday, April 1, 2024

April 2024 Science Summary

Art at the Kennedy center


Just three articles this month: how wetland restoration affects climate mitigation, how climate change is affecting seasonality of river flow, and a summary of how people use plants around the world.

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).

Schuster et al. 2024 reviews the net climate impact of wetland restoration, considering carbon, methane, and nitrous oxide. Their headline is that it takes 525 years for restoring peat to result in net climate cooling (b/c short-term methane increases offset the carbon gains), and 141 years for non-peat wetlands (marshes, riparian wetlands, and swamps). They argue other more positive estimates have left out nitrous oxide. BUT they are looking just at the restoration over time NOT comparing restored wetlands to the baseline of degraded wetlands (since drained peat also emits methane and lots of CO2, the time would be a lot shorter to be net climate cooling. Some other papers I've read (e.g., Richardson et. al 2022 on pocosin) found minimal methane emissions making restoration a clear winner even in the short term. I asked a couple experts about this paper and they also flagged that while in the short term we should be worried about methane, it's also true that: the alkalinity export from peat could make them MORE cooling than we think, and that there are other ecosystem services to consider.

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.

Pironon et al. 2024 is a global analyis of plants used by humans (directly or indirectly - medicinal uses dominate but they look at nine other types of use, see Fig 2). See Fig 1a for a map of how many plant species are used around the world. They find 1) people use more plant species in places where most plant species exist, 2) Indigenous lands use slightly fewer species than neighboring non-Indigenous regions, and 3) protected lands use slightly fewer species than non-protected lands. These are correlations - they don't control for income or many other covariates. And from a conservation perspective we may not want all species to be used, especially rare ones!Note there are some problems with the data, e.g., Figure S1 shows how poor the sampling density is outside of the US, Central America, Europe, and Australia. Finally, they only found 971 species of plants that provide food to bugs we use (honeybees, silkworms, lac insects, and grubs) which seems really low. There's an article about this at: https://www.unep-wcmc.org/en/news/plants-and-their-contributions-to-people-are-insufficiently-protected-globally

Pironon, S., Ondo, I., Diazgranados, M., Allkin, R., Baquero, A. C., Cámara-Leret, R., Canteiro, C., Dennehy-Carr, Z., Govaerts, R., Hargreaves, S., Hudson, A. J., Lemmens, R., Milliken, W., Nesbitt, M., Patmore, K., Schmelzer, G., Turner, R. M., van Andel, T. R., Ulian, T., … Willis, K. J. (2024). The global distribution of plants used by humans. Science, 383(6680), 293–297. https://doi.org/10.1126/science.adg8028

Schuster, L., Taillardat, P., Macreadie, P. I., & Malerba, M. E. (2024). Freshwater wetland restoration and conservation are long-term natural climate solutions. Science of The Total Environment, 922(August 2023), 171218. https://doi.org/10.1016/j.scitotenv.2024.171218

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

p.s. This photo is of a sculpture at the Kennedy Center by ByeongDoo Moon called "I have been dreaming to be a tree"

Friday, March 1, 2024

March 2024 science summary



This month I have two articles on wildlife connectivity, one on global groundwater depletion, one on scientific reproducibility, and one on organizational behavior change.

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).

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.

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 hotpsots 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

Iverson et al. 2024 cautions against assuming that modeled wildlife corridors connecting habitat patches ('linkages') actually receive much heavier use by wildlife. They looked at five linkage models in CA (see Fig 1), and compared them to 1) wildlife-vehicle collisions and 2) modeled wildlife presence (from a large set of wildlife observations). While black bear and puma vehicle collisions were slightly more likely in linkages, racoon collisions were LESS likely in linkages, and the other five species assessed were mixed depending on model. Across all eight species no model did consistently well for either wildlife vehicle collisions nor modeled occupancy. The authors note that the linkage models were all built on human disturbance metrics, but that another study found those metrics only significantly drove away about 1/3 of mammal species studied (including big carnivores and omnivores). Since wildlife don't have apps to find optimal travel routes, it's not shocking that they're not heavily using linkages. But this study is a good reminder to be wary of relying on models for citing narrow corridors, and it's a safer bet to assume wildlife presence is not typically highly concentrated.

Thurman et al. 2024 argues that it's important to consider disease when doing conservation planning and wildlife management. One key point is that in some cases improving connectivity can be net harmful for some species. The case of prairie dogs and black-footed ferrets on the top of page 3 is fairly compelling (the impact of plague is high enough that mitigating its spread should be a priority). Overall, I think it's fair to say that species and ecosystems need climate-resilient connectivity options to adapt to climate change, even if increased disease transmission offsets the benefits somewhat. But thinking about disease and if/how to incorporate it in planning should always be a good idea. I like the orange questions in Figure 1, but found the longer list in Table 1 to be overwhelming (which could make it harder for planners to act). There's no silver bullet being offered here, but maybe they're warning us to watch out for 'friendly fire' (unintended negative impacts of promoting connectivity w/o thinking about disease).

Ferraro et al. 2019 is a non-peer-reviewed working paper that asks whether behavioral psychology nudges known to influence individuals work on organizations too. They looked at a national organization asking for voluntary membership does from 3,000 nonprofits, and tested 1) crafting a clear and salient ask to emphasize public benefits, 2) publicly sharing who contributed and by how much, and 3) showing quarterly progress towards a national goal. All had no effect (each treatment on average made contributions very slightly lower, but w/o statistical significance). The authors hypothesize (w/ evidence from other studies) that group decision making makes orgs less responsive than individuals to these kinds of interventions. An interesting follow-up study would be to target individuals with the individual authority to make decisions that affect the broader organization and see if that works.


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

Ferraro, P. J., Weigel, C., An, J., & MESSER, K. D. (2019). Nudging Organizations: Evidence from three large-scale field experiments (Vol. 21211). https://doi.org/10.1257/rct.4238-3.0

Iverson, A. R., Waetjen, D., & Shilling, F. (2024). Functional landscape connectivity for a select few: Linkages do not consistently predict wildlife movement or occupancy. Landscape and Urban Planning, 243(March 2023), 1–12. https://doi.org/10.1016/j.landurbplan.2023.104953

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

Thurman, L. L., Alger, K., LeDee, O., Thompson, L. M., Hofmeister, E., Hudson, J. M., Martin, A. M., Melvin, T. A., Olson, S. H., Pruvot, M., Rohr, J. R., Szymanksi, J. A., Aleuy, O. A., & Zuckerberg, B. (2024). Disease‐smart climate adaptation for wildlife management and conservation. Frontiers in Ecology and the Environment, 1–10. https://doi.org/10.1002/fee.2716

p.s. The photo is of a piece called "Shift" by Lisa Wood Studios, and it cycled between saying "Unconscious consumption" and "Conscious conservation" (presumably what we have now) and then as shown above "conscious consumption" and "unconscious conservation" (which makes less sense to me, but presumably means we're mindful of our choices and conservation happens automatically?

Thursday, February 1, 2024

February 2024 science summary

Snowflake ornament illuminated by Christmas tree lights


This month is a bit of a grab bag again with an article on freshwater protection, another on koala-vehicle strikes, and two on soil carbon (both offering caution on the potential and flagging complexity).

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).

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.

Dexter et al. 2023 makes a point that seems obvious once you think about it, but which was new to me. Namely, hotspots of wildlife-vehicle collisions (they looked at koala strikes) are likely to be very dynamic over time as wildlife populations grow and shrink, as land use change drives shifts in their movement, and as roads and traffic change. They make the point that wildlife crossings are generally cited based on past collision data, and found that collision hotspots decline over time (as nearby populations decline and/or move). There was some unspecified 'road mitigation' which could have partially driven the reductions but the authors said the mitigation wasn't sufficient to explore the decline (pointing to unpublished data, unfortunately). They recommend instead taking a broader landscape approach considering habitat and trends as opposed to focusing crossings at local collision hotspots, and including crossings or other mitigation early when making infrastructure changes.

Ogle et al. 2023 looks at the soil carbon portion of U.S. plans to meet their contribution to the Paris agreement on climate mitigation. They review several well known challenges w/ soil carbon (C): changes are hard to predict and measure accurately, that additionality and permanence can be challenges, and that changing practices can have undesirable side-effects (increasing emissions from soil of strong GHGs like nitrous oxide or methane, shifting emissions to other farms, etc.). See Table 1 for a summary. They also provide an overview of policy options including mandates, subsidies and incentives, C taxes, and C offsets (see Table 2). They call for a suite of research to investigate these challenges and look for a path forward if one exists.

Wang et al. 2023 is a helpful review of the degree to which soil carbon sequestration can offset greenhouse gas (GHG) emissions from ruminants (mostly cattle, but also sheep, goats, and buffaloes). It's a nice example of fairly simple analysis revealing important insights. Their top level finding is that to offset ruminant emissions from manure and burping over a 100 year timeframe, we would need to roughly triple the current total global carbon stock in managed grasslands (adding 200% to existing stocks), with regional increases needed from ~25%-2000% (Fig 4b, and see 4c which is per ha). That large an increase is not feasible; while reducing net emissions on ranches is important, we shouldn't expect to get the global beef & other ruminant sector to help mitigate climate change on net. That's perhaps obvious, but fringe local cases of low-density ranches w/ lots of nature potentially being carbon negative are often cited as examples of something globally scalable, so it's a useful reminder that they are not unless we reduce the global supply of ruminants (farm and eat less of their meat and dairy). Fig 3 summarizes how cattle factor into this in a different way: depending on how a given grassland can sequester and how much methane each cow produces, the "offsettable" cattle density ranges from 0 to 1.2 (for the very best case scenario).

Dexter, C. E., Scott, J., Blacker, A. R. F., Appleby, R. G., Kerlin, D. H., & Jones, D. N. (2023). Koalas in space and time: Lessons from 20 years of vehicle‐strike trends and hot spots in South East Queensland. Austral Ecology, June 2021, 1–18. https://doi.org/10.1111/aec.13465

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

Ogle, S. M., Conant, R. T., Fischer, B., Haya, B. K., Manning, D. T., McCarl, B. A., & Zelikova, T. J. (2023). Policy challenges to enhance soil carbon sinks: the dirty part of making contributions to the Paris agreement by the United States. Carbon Management, 14(1). https://doi.org/10.1080/17583004.2023.2268071

Wang, Y., de Boer, I. J. M., Persson, U. M., Ripoll-Bosch, R., Cederberg, C., Gerber, P. J., Smith, P., & van Middelaar, C. E. (2023). Risk to rely on soil carbon sequestration to offset global ruminant emissions. Nature Communications, 14(1), 7625. https://doi.org/10.1038/s41467-023-43452-3
p.s. This is a photo of a handmade glass snowflake ornament reflecting and transmitting several colors of Christmas tree lights