Geology topics

Lisa A. Schulte

Publications and source records attributed to Lisa A. Schulte.

6 recordsLinked to original sources

USGS2024

The relative contributions of habitat area, configuration, and vegetative diversity on snake and lizard presence in agricultural landscapes

Nearly one in five reptile species is at risk of extinction. Changes in habitat area, its configuration, and vegetation diversity could affect habitat use, but their relative importance is understudied. We assessed how these factors affected reptile presence in agricultural landscapes figure in Iowa, United States, using 695 cover boards visited 16,441 times in 2015–2020. Species-wise encounter rates ranged 0.0001–0.012. Eight of 11 species and 54.2% of individuals were species of greatest conservation need. Habitat area, configuration, and vegetation diversity influenced reptile presence similarly. Mean patch occupancy was 0.18 for common garter snake (CG, Thamnophis sirtalis ) and 0.45 for all snakes (AS). Naïve presence was explained by effort (odds ratio [OR] AS = 1.83, OR CG = 1.79), vegetation diversity (OR AS = 1.28, OR CG = 1.28), woody cover (OR AS = 1.24, OR CG = 1.41), and patch size (OR AS = 1.30). Large patch prairies were more likely to contain snakes than other conservation practices ( 𝑟̂ encounter = 0.291), and more likely to contain CG (0.098) than prairie contour strips (0.031), waterways (0.018), grass contour strips (0.016), or terraces (0.015). While we documented low overall reptile presence, their higher presence in large prairie patches underscores the importance of core nature reserves for reptile conservation.

Iowa↗

USGS2024

Habitat amount and edge effects, not perch proximity, nest exposure, or vegetation diversity affect cowbird parasitism in agricultural landscapes

Context Prior research documented relationships between brown-headed cowbird ( Molothrus ater ) brood parasitism and edge effects, proximity of perches, and nest exposure. Those relationships have not been evaluated in agroecosystems containing extremes of fragmentation and vegetation diversity. Objectives We compared three existing hypotheses on how cowbirds locate host nests with two new hypotheses regarding habitat amount and vegetation diversity to determine how the configuration and location of agricultural conservation practices affect grassland bird nest parasitism rates and predicted rates for eight common conservation practices. Methods We assessed cowbird parasitism of grassland bird nests on corn and soybean farms in Iowa, USA, and measured perch proximity, nest exposure, edge effects, habitat amount, and vegetation diversity for each nest. We fit a global generalized linear mixed-effects model and compared importance of model parameters using odds ratios. We predicted parasitism likelihood for every subset model and averaged predictions to explore individual effects. Results The variables that most influenced parasitism rates included main effects for nest initiation day-of-season (OR = 0.71, CI 95 = 0.60–0.84) and the landscape variables of distance to nearest crop edge (0.63, 0.51–0.76) and proportion of grass land cover within 660 m (0.75, 0.57–1.00). We found little support that perch proximity, nest exposure, or native vegetation diversity affected parasitism. We also assessed parasitism likelihood by conservation practice and found no significant differences. Conclusions Our results provide evidence to support the edge effect and habitat amount hypotheses, but not the nest exposure, vegetation diversity, or perch proximity hypotheses.

Iowa↗

USGS2024

Bird community response to field-level integration of prairie strips

Grassland birds are under threat worldwide due to loss of habitat to agriculture. Prairie strips are a new agricultural conservation practice composed of linear strips of reconstructed diverse, native, herbaceous, perennial vegetation designed to promote land sharing among agriculture and biodiversity, while also addressing soil and water conservation goals. We evaluated bird community response to establishment of prairie strips on commercial row-crop fields (corn [( Zea mays ] and soybean [ Glycine max ]) in Iowa, USA compared to controls fields without prairie strips, from 2015 to 2020. We found a 2.94-fold higher density of grassland birds on fields with prairie strips compared to control fields, and a 1.87-fold higher density of birds overall. Time since prairie strip establishment was a significant predictor of grassland bird density, with significant increases between years 1 and 2 and years 3 and 4. Species with the strongest positive response to prairie strips were Red-winged Blackbird ( Agelaius phoeniceus ), Common Yellowthroat ( Geothlypis trichas ), Western Meadowlark ( Sturnella neglecta ) and two species of greatest conservation need: Dickcissel ( Spiza americana ) and Eastern Meadowlark ( Sturnella magna ). Diversity measures (e.g., Shannon’s and Simpson’s indices) did not differ between fields with prairie strips versus those without. Prairie strips provide quality breeding habitat for a suite of species, including grassland species and those of conservation concern. While improving several bird community measures, prairie strips do not provide habitat for area-sensitive grassland birds. Larger grassland patches are needed, potentially managed as land-sparing reserves, to achieve overall biodiversity goals in agricultural landscapes.

Iowa↗

USGS2021

Miniature temperature data loggers increase precision and reduce bias when estimating the daily survival rate for bird nests

Demographic studies of many bird species are challenging because their nests are cryptic, resulting in few nests being found. To maximize statistical power, methods are needed that minimize disturbance while yielding as much information per nest as possible. One way to meet these objectives is to use miniature thermal data loggers to precisely date nest fates. Our objectives, therefore, were to (1) examine the possible effect of thermal data loggers on nest success through hatching by grass- and shrub-nesting songbirds that differed in their parasite egg-accepting and -rejecting behavior, (2) examine the effect of using daily temperature data versus less frequent nest-visit data on statistical power, bias, and precision when estimating the daily survival rate (DSR) for nests, and (3) compare these two approaches using a simulation study and field data. We monitored the survival of nests located in agricultural landscapes and used a binomial logistic regression with main effects for data-loggers and parasite-accepting or -rejecting status and their interaction. We also compared maximum likelihood–derived DSR for differences in estimated rates, precision, and sample sizes with both data collected in the field and simulated with varying sample sizes and visit frequencies. We found no evidence that thermal data loggers had any effect on hatching rates either for all species or for parasite egg-accepting and -rejecting species, separately. Both our simulation and analysis of real nest data indicated that use of data loggers increased the statistical power from each nest studied by increasing effective sample sizes and precision of DSR estimates compared to in-person visits. We also found a negative bias in DSR estimates with longer visit intervals, which use of data-loggers removed. Both the results of simulated- and field-data analyses suggest that future studies of nest survival can be improved by automated nest monitoring by removing a source of bias and providing more time to find additional nests.

Iowa↗

USGS2019

Quantifying thermal-imager effectiveness for detecting bird nests on farms

We conducted a designed experiment to test whether having a thermal-imaging camera available affected researchers' nest detection rates when searching for bird nests in cropland and grassland habitat in an agricultural landscape of Iowa, USA, in 2016. With known active nests present, naïve observers searched for nests with and without a thermal imager available. We did not find a difference in detection probabilities, although only a large difference would have been detectable with our sample size. Extraneous heat signatures from reflected solar radiation and dense vegetation were key factors limiting the usefulness of thermal imagers for locating nests.

Iowa↗

USGS2017

Neonicotinoid insecticide removal by prairie strips in row-cropped watersheds with historical seed coating use

Neonicotinoids are a widely used class of insecticides that are commonly applied as seed coatings for agricultural crops. Such neonicotinoid use may pose a risk to non-target insects, including pollinators and natural enemies of crop pests, and ecosystems. This study assessed neonicotinoid residues in groundwater, surface runoff water, soil, and native plants adjacent to corn and soybean crop fields with a history of being planted with neonicotinoid-treated seeds from 2008-2013. Data from six sites with the same crop management history, three with and three without in-field prairie strips, were collected in 2015-2016, 2-3 years after neonicotinoid (clothianidin and imidacloprid) seed treatments were last used. Three of the six neonicotinoids analyzed were detected in at least one environmental matrix: the two applied as seed coatings on the fields (clothianidin and imidacloprid) and another widely used neonicotinoid (thiamethoxam). Sites with prairie strips generally had lower concentrations of neonicotinoids: groundwater and footslope soil neonicotinoid concentrations were significantly lower in the sites with prairie strips than those without; mean concentrations for groundwater were 11 and 20 ng/L (p = 0.048) and <1 and 6 ng/g (p = 0.0004) for soil, respectively. Surface runoff water concentrations were not significantly (p = 0.38) different for control sites (44 ng/L) or sites with prairie strips (140 ng/L). Consistent with the decreased inputs of neonicotinoids, concentrations tended to decrease over the sampling timeframe. Two sites recorded concentration increases, however, potentially due to disturbance of previous applications or influence from nearby fields where use of seed treatments continued. There were no detections (limit of detection: 1 ng/g) of neonicotinoids in the foliage or roots of plants comprising prairie strips, indicating a low likelihood of exposure to pollinators and other insects visiting these plants following the cessation of seed coating use. Offsite transport of neonicotinoids to aquatic systems through the groundwater and surface water were furthermore reduced with prairie strips. This study demonstrates the potential for prairie strips comprising 10% of an agricultural catchment to mitigate the non-target impacts of neonicotinoids.

Agriculture, Ecosystems and Environment↗