Eric R. Larson
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ericrlarson.bsky.social
Eric R. Larson
@ericrlarson.bsky.social
2.6K followers 4.8K following 150 posts
Associate professor in freshwater ecology, University of Illinois at Urbana-Champaign. Crayfish, invasive species, environmental DNA, and more. https://publish.illinois.edu/erlarson/
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ericrlarson.bsky.social
Do precipitation events have opposing effects on aquatic versus terrestrial environmental DNA (eDNA) recovered from streams and rivers? New from the lab at Ecological Applications: doi.org/10.1002/eap....
Linear mixed model predictions for aquatic (blue solid) and terrestrial taxa richness (brown dotted) in response to (A) rainfall (in centimeters) and (B) water temperature (in degrees Celsius) with 95% CIs.
January 12, 2026 at 4:48 PM
Reposted by Eric R. Larson
oldenfish.bsky.social
National assessment of river protection in the U.S.

Article: doi.org/10.1038/s418...
Policy Brief: doi.org/10.1038/s418...
Rivers Explorer: map.myriver.americanrivers.org

Collaboration b/t American Rivers, Conservation Science Partners, Univ WA @americanrivers.bsky.social

Thread 👇 | DM for PDF
Image of river protection status in the United States
January 9, 2026 at 6:18 PM
ericrlarson.bsky.social
Excited that our newly described Okanagan Crayfish makes an appearance on the CBC's cool species of 2025 list: www.cbc.ca/news/science...
Tarantula with XXL genitalia, 'death ball' sponge among cool species of 2025 | CBC News
A spider with extraordinary genitalia, a carnivorous caterpillar that wears its prey's body parts, and a tiny opossum are among the cool new species described by science in 2025.
www.cbc.ca
January 7, 2026 at 6:46 PM
Reposted by Eric R. Larson
jcorush.bsky.social
I'm recruiting a Ph.D. student for Fall 2026.

Interested in comparative studies and trait evolution in fishes?

Send me an email with a CV and research interests. Please take a look at my website (jcorush.github.io ) for more information about my research.

#hybridization #minnows #mudskippers
Corush Lab
jcorush.github.io
December 4, 2025 at 12:38 AM
ericrlarson.bsky.social
The Sangamon River of Illinois through the seasons. We visited this site every few weeks in 2025 to track changing stream communities with environmental DNA.
A red covered bridge over a river in winter with shallow snow on both banks and thin, clear ice covering most of the surface of the water A red covered bridge seen from a river bank in early spring, with silver maple trees beginning to leaf out. The river is turbid, with sycamores visible on the far bank. A red covered bridge seen from mid-channel of a turbid river in mid-summer, with forest on both banks A red covered bridge in late fall with drifts of slush on its roof, seen from mid-channel of a wadeable river. Most trees have lost their leaves.
December 6, 2025 at 2:51 PM
ericrlarson.bsky.social
New OA study led by Dr. Caitlin Bloomer of U. Illinois: can you predict good habitat for burrowing crayfish even if your model is trained on data from different burrowing crayfish species (doi.org/10.1111/fwb....)? Highly relevant to these hard-to-detect and identify animals.
Two crayfish burrows seen from above or plan view Two crayfish burrows seen from the side at an angle, where one burrow is about three times taller than its neighbor. The burrows are in surprisingly coarse or sandy substrate, with some fine, gray to orange pebble noticeable in the taller burrow.
December 4, 2025 at 5:02 PM
ericrlarson.bsky.social
Riparian buffers help more than just streams and rivers in agricultural landscapes. Lab Masters student Olivia Reves used environmental DNA (eDNA) to quantify the benefit of riparian buffers to terrestrial wildlife in downstate Illinois; open access at doi.org/10.1111/1365...
A figure showing a stream without a forested riparian buffer in the top panel and a stream with a forested riparian buffer in the bottom panel. A cartoon water bottle with a DNA symbol in each water bottle directs to adjacent insets with silouttes of representative wildlife at each stream, with the forested stream having more species and including amphibians, reptiles, bats, and flying squirrels.
December 3, 2025 at 3:06 PM
Reposted by Eric R. Larson
tomewing.bsky.social
Handshake meme - "Me doing a CAPTCHA" and "THE THIRD POLICEMAN by Flann O'Brien" uniting over "Is the guy riding the bicycle part of the bicycle?"
November 23, 2025 at 9:34 PM
ericrlarson.bsky.social
New invasion note from southern Idaho, where we've rediscovered the non-native red swamp crayfish after a half century without detection (doi.org/10.3391/bir....). Intensive burrowing by red swamp crayfish could be a risk to canals and other irrigation infrastructure.
An irrigation ditch centered in the image that has dried to a single, isolated pool in the foreground. There are grassy banks on either side of the ditch, with two men standing on the right bank in an orange sweatshirt and blue shirt.
November 10, 2025 at 5:04 PM
ericrlarson.bsky.social
New faculty position in the University of Illinois Department of Natural Resources and Environmental Sciences for an assistant or associate professor of agroecology: illinois.csod.com/ux/ats/caree.... Position closes October 31st. Happy to answer questions about the dept / university / town.
A prairie with a wetland in the middle distance and a tree line on the horizon under low, scattered clouds
September 24, 2025 at 9:29 PM
Reposted by Eric R. Larson
corriemoreau.bsky.social
UPDATE: The 2025-2026 list of faculty and postdoc positions in ecology and evolutionary biology is out! Be sure to check out this active and helpful community run resources! docs.google.com/spreadsheets...
ecoevojobs.net 2025-26
docs.google.com
September 19, 2025 at 9:47 PM
Reposted by Eric R. Larson
beetlemoses.bsky.social
September 12, 2025 at 3:34 PM
ericrlarson.bsky.social
Completed my annual trip to northern Wisconsin, continuing population monitoring of invasive rusty crayfish (Faxonius rusticus) that extends back to the 1970s. Populations remain down, at only ~25% of past peak abundances, with surprising catches of large native snails in our traps.
A slightly out of focus rusty crayfish (Faxonius rusticus) held between a thumb and forefinger with the calm surface of a lake in the background Two boats docked in the foreground of a large lake with a yellow floating platform in the middle distance and a forested shoreline ~2 miles back on the horizon Sunset on a large, calm lake as a band of orange below emerging stars A square white bucket with ~16-20 rusty crayfish (Faxonius rusticus) waiting to be counted and measured
September 6, 2025 at 3:00 PM
Reposted by Eric R. Larson
oldenfish.bsky.social
It was a real pleasure to participate in the Mazama Newt Workshop at Crater Lake hosted by the @oregonzoo.bsky.social and the National Park Service. Discussions focused on a recovery plan for the Mazama newt in light of an exploding invasive signal crayfish. Great to see @ericrlarson.bsky.social!
August 26, 2025 at 11:39 PM
Reposted by Eric R. Larson
chicagotribune.com
The RELIX catalogues every plant species in 353 prairie remnants — parts of the native grasslands of the Midwest that were not converted to farmland during colonization.
New database catalogs plant species in latest effort to restore prairies
The RELIX catalogues every plant species in 353 prairie remnants — parts of the native grasslands of the midwest that were not converted to farmland during colonization.
www.chicagotribune.com
August 23, 2025 at 9:00 PM
ericrlarson.bsky.social
Our search for invasive crayfish barriers includes more than just dams or irrigation diversions. Because the virile crayfish is intolerant of stream drying (doi.org/10.1086/725318), intermittent reaches could present barriers to upstream spread to permanent streams in the mountains.
An isolated stream pool above a culvert (not visible, where the photographer is standing) with a dry bed upstream. The pool is turbid and surrounded by dry steppe, with mountains visible in the distance under a mostly sunny sky.
August 19, 2025 at 3:46 PM
ericrlarson.bsky.social
Crayfishing.
Two researchers hold a seine downstream of them in a moderately wide, rocky river Two researchers check hand nets while overturning rocks on the shoreline of a reservoir Two researchers check dip nets along the shore of a stream impounded behind an irrigation diversion
August 12, 2025 at 10:50 AM
ericrlarson.bsky.social
The manager at this property noted they have problems with the invasive crayfish clogging irrigation infrastructure downstream of the diversion. Economic damages to agriculture from invasive crayfish are well-known on other continents, but I wonder if we've missed an impact in the arid western US.
ericrlarson.bsky.social Eric R. Larson @ericrlarson.bsky.social · Aug 7
This was another barrier where non-native crayfish passage was obvious before we started sampling. Here a small gate in one of the water control structures was clogged with carcasses from the upstream pool. I think this barrier is open to flow at times of the year when crayfish are moving around.
A cat door-sized panel in a water control structure or dam that is partially open but clogged with debris, letting out a small flow of water. A close-up of a small panel or gate in a water control structure that is clogged with both aquatic plant debris and noticeable crayfish carcasses, including visible walking legs and abdomens
August 8, 2025 at 5:11 PM
ericrlarson.bsky.social
This irrigation diversion looked promising as an invasive crayfish barrier. The diversion gates didn't appear to be climbable. Water is diverted into a buried pipe with screens to prevent fish entrainment. Concrete retaining walls extend into the riparian zone. Can crayfish get over or around this?
An irrigation diversion in an arid landscape backing up water behind it, with a shallow, rocky stream below. The diversion consists of a series of concrete retaining walls and metal water controls that can be raised or lowered.
August 6, 2025 at 2:08 PM
ericrlarson.bsky.social
A relief to add a new pilose crayfish site this week. This native species disappeared from the mainstem, low elevation Bear River in Wyoming between 1987 & 2007, replaced by the non-native virile crayfish (peerj.com/articles/5668/). Remnant populations are confined to higher elevation tributaries.
A pilose crayfish (Pacifastacus gambelii) held close to the camera with a five gallon bucket and clipboard out of focus in the background on a grassy river bank. The pilose crayfish is mottled olive brown and yellow, with distinctive strips of hair on the lateral, dorsal surface of its visible claw.
August 1, 2025 at 8:55 PM
ericrlarson.bsky.social
Freshwater invaders pose unique challenges to species distribution (or ecological niche) models used in risk analysis. New in Freshwater Science (doi.org/10.1086/737200), I identify strategies to improve predictions of suitable habitat for emerging, data-poor freshwater invaders using these tools.
The manuscript title "Predicting potential distributions of freshwater invasive species in novel environments" above the author Eric R. Larson and an affiliation at the University of Illinois, with a conceptual figure illustrating the transfer of invasion risk information from a widely distributed to an emerging, prospective invasive species. The figure's caption from the paper reads "Researchers might borrow information from supraspecific modeling units, sometimes termed avatar species or surrogate species, to make precautionary habitat suitability estimates for species under evaluation as prospective invaders that lack nonnative occurrence records. The simple example here uses BioClim bounding boxes (Busby 1991) on only 2 predictor variables to quantify underestimation of abiotic tolerances for a widely distributed invader when using only native-range occurrences relative to a total model that incorporates nonnative occurrences (A). The magnitude of this underestimation can be transferred to a species with only native-range occurrence data under evaluation as a prospective invasive species (B). Transferring this information may need to account for asymmetrical shifts in abiotic tolerances or changes in the direction of relationships between multiple predictor variables (Larson et al. 2014) and might also use the supraspecific modeling unit to identify total range-informed thresholds of habitat suitability for transfer (Liu et al. 2005)."
July 31, 2025 at 7:44 PM
Reposted by Eric R. Larson
uslter.bsky.social
The publications collected in this month's LTER Network News really demonstrated the wide range of impactful research the LTER does. Here's the list:

mailchi.mp/lternet/lter...
LTER Network News | July 2025
mailchi.mp
July 31, 2025 at 6:32 PM
ericrlarson.bsky.social
Here's another potential invasive crayfish barrier: a concrete structure extending across a river channel associated with a municipal water supply diversion. Can crayfish get over/around this, or not?
A view across a river channel centered on a small concrete dam or water control structure, which extends into the riparian zone and has a noticeable drop or plunge at its downstream end. The river is shallower and rocky below the dam and deeper above.
July 30, 2025 at 3:00 PM
ericrlarson.bsky.social
More hints that one of our study sites is a good place to catch crayfish
A latrine pile of crayfish fragments with a low gradient river in the background
July 29, 2025 at 7:33 PM