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 (, 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!

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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.

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.

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.

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.

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