NEON tick drag data (2014–2024) show no common density trend: lone star ticks increased at one Kansas site and decreased at four eastern sites, and Asian longhorned ticks increased in Virginia
Question: did the density of questing ticks change at National Ecological Observatory Network (NEON) sites from 2014 to 2024? NEON drags a cloth along fixed 160 m plot edges at all sites, and it records zero catches. Approach: we used the public NEON tick Darwin Core Archive (published 2026-09-15; 13,748 sampled plot visits at 46 sites after we removed 208 visits with missing identification). For each site and species-stage, we fitted Poisson log-linear models with plot effects, a day-of-year spline, a dragged-length offset and a linear year term, with year-clustered and year-jackknife errors. Then we pooled the site trends with random-effects meta-analysis and did 7 sensitivity variants. Results: pooled trends were near zero (lone star nymphs -3.8%/yr, 95% CI -15.0 to +8.9; blacklegged nymphs +2.3%/yr, -12.4 to +19.5; American dog tick adults +4.6%/yr, -8.1 to +19.0). The between-site SD of the trends was about 13 to 19%/yr. Lone star nymphs increased at the University of Kansas site UKFS by 26.7%/yr (15.4 to 39.1; all plots and all variants). They decreased at LENO, TALL and SCBI, and lone star adults decreased at ORNL. The west-minus-east difference was +24%/yr for adults (p = 0.033) and +22%/yr for nymphs (p = 0.12), but it depends mainly on one site. Blacklegged nymphs decreased at SERC (-16%/yr) and increased at MLBS. NEON samples contain the invasive Asian longhorned tick at SCBI and BLAN (Virginia) from April and June 2017. At SCBI, the nymph catch increased from 7 in 2017 to 265 in 2023, and at BLAN it was 180 in 2024. Native ticks did not decrease more at these two sites than at other eastern sites. Borrelia burgdorferi s.l. prevalence in tested blacklegged nymphs had no pooled trend (OR 0.97 per year). Main limitation: with 7-11 sites and 10-11 years, only pooled trends of about 20%/yr or more are detectable, and single-site trends can come from local habitat or host change.
ticks · Amblyomma americanum · Ixodes scapularis · Haemaphysalis longicornis · Dermacentor variabilis · NEON · drag sampling · population trends · invasive species · Borrelia burgdorferi · meta-analysis · vector ecology
References
4- usesdoi:10.15468/b52b9z
NEON ticks sampled using drag cloths and tick pathogen status, Darwin Core Archive (version published 2026-09-15); the only input data.
- usesdoi:10.48443/5e20-3763
NEON DP1.10093.001 RELEASE-2026, the source data product of the Darwin Core Archive.
- doi:10.46471/gigabyte.56
Data paper that describes the NEON tick abundance, diversity and pathogen data and protocol.
- doi:10.1093/jme/tjy006
First reported US field detection of Haemaphysalis longicornis (New Jersey, 2017), compared with the NEON first-detection dates.
Cited by
5 publicationsPublic catalog entries on Sciscape.
- In NEON tick drags 2014–2024, blacklegged nymph counts were lower and lone star adult counts higher on dry sampling days, and a dry summer did not lower next-year counts
[Legacy relation: reproduces] Our independent trend method reproduces its site trends (r = 0.997 over 41 site x species-stage pairs) and near-zero network means; we use one of its CC BY 4.0 result tables for the comparison.
- usesThe latitude change in NEON blacklegged nymph catches reversed when the early period changed from 2016–2018 to 2017–2019
Reuses the retained source archive and unchanged MIT visit-building code. Extends site-trend work with a latitude-center audit.
- usesThe matched lone star to blacklegged nymph ratio rose from May–June to July–August across four NEON sites (2016–2023)
We reuse its retained source archive and follow its missing-taxonomy and partial-identification cleaning rules. We test a seasonal contrast rather than an annual density trend.
- In NEON collection events in 2014–2024, Borrelia burgdorferi-positive Ixodes scapularis nymphs had 3–6 times higher odds of Babesia microti, Ehrlichia muris and Anaplasma, but not of B. miyamotoi
[Legacy relation: reproduces] Our independent implementation reproduces its 41 site density trends (r = 0.997); for 6 series the significance depends on the standard-error method.
- NEON ticks, 2014–2024: site density trends did not follow site temperature, lone star ticks stayed absent at five northern sites, and dog ticks but not blacklegged ticks followed prior-year rodents
[Legacy relation: reproduces] We reproduce its pooled and site density trends with an independent pipeline (neonDivData, allocation of unidentified ticks, negative binomial models): pooled values within 1 percentage point per year, site trends r = 0.965. We reuse its site trend table only for the comparison.