Diagnosing the variability in prospective inter-specific interactions informs both our understanding of particular species as well as how the ecological complex of which they can be a part are altered by their presence. This study uses empirical field descriptions, complemented by published floras and the resources at centers for species conservation, to explore macro-ecological patterns in interactions between plants and ants. I describe on-plant foraging by ants on 70 plant species (11 families, 29 genera) in the Sonoran Desert region, highlighting particular combinations of plant species, ontogenetic stages, and season where forager visitation is disproportionately high or low. Through my plant-ant association surveys, I find species-specific descriptions of on-plant foraging: (1) are qualitatively similar among sites (an arboretum and a wilder location), (2) can predict the activities of ground foraging ants at the patch scale (plant neighborhoods of 12 m²), (3) show plant community types within the warm North American deserts have diverging likelihoods of on-plant foraging, and (4) brief inspections can describe among-plant variation in likelihoods of visitation by ants as well as herbivores that can be deterred by ants.

Nonnative invasive species are a threat to biodiversity worldwide. One common method for invasive species management is biological control (biocontrol). However, biocontrol can have unanticipated nontarget effects on native species. Cirsium pitcheri (Pitcher's thistle) is a federally threatened plant endemic to the Great Lakes dunes. Unfortunately, a formerly-recommended biocontrol weevil (Larinus carlinae, used in an effort to control Cirsium arvense and previously referred to as Larinus planus within the biocontrol literature) impacts Ci. pitcheri seed production in large portions of its range and is contributing to population declines. Two congeneric species of weevil (L. minutus and L. obtusus), introduced to control spotted knapweed (Centaurea stoebe subsp. micranthos), may pose a similar risk of nontarget interactions with Ci. pitcheri. All three weevil species have been known to use both Cirsium and Centaurea species in their European range. To understand weevil preferences, we performed a set of choice and nonchoice trials under laboratory conditions in order to test whether the three weevil species are more flexible in their host preferences than previously known, using adult weevils and substituting Ci. arvense for Ci. pitcheri in the case of L. carlinae, due to limited availability of the latter, endangered thistle. All three weevil species spent more time feeding on their intended/known hosts but also fed on the nontarget species, and in some cases the differences were not significant. All three weevil species always oviposited on their known hosts, with no ovipositions on the other test species. Based on our results, neither L. minutus nor L. obtusus is likely to be a major threat to Ci. pitcheri, and L. carlinae is unlikely to use Ce. stoebe as a host.

Over the last century, nonnative earthworms have invaded forests of the Great Lakes region of North America. Although a growing body of scientific research has documented short-term changes associated with invasive earthworms, there is little research describing the effects of invasive earthworms over multiple decades. To investigate the long-term effects of invasive earthworms on forests, sites sampled in the past need to be classified as wormed or unwormed when originally sampled. However, this is often difficult to accomplish because field methods for sampling earthworms have only recently been developed, and the few historical permanent sites available for resampling largely do not have past information about earthworm presence or absence. Although historic sites lack data on invasive earthworm presence, many of these sites do have information about soil horizon thickness. Therefore, soil horizons can potentially be used as an indicator of the presence or absence of invasive earthworms. In this paper we developed a logistic regression generalized linear model to classify 40 sugar maple-basswood sites in the Chippewa National Forest of Northern Minnesota as wormed or unwormed (i.e., presence or relative absence of earthworms, respectively). A model using the thickness of the O horizon as a predictor variable correctly classified 93% of sites resampled in 2017 as wormed or unwormed. This result suggests we can predict which sugar maple-basswood stands in the Chippewa National Forest were wormed in the past. By comparing historic conditions to those present today, we can then analyze the long-term effects of invasive earthworms.

We conducted a 2 y study of survival and cause-specific mortality of elk (Cervus elaphus) calves to determine the current status of elk occupying the southwestern region of the Black Hills National Forest, South Dakota and eastern Wyoming. We captured and fit 71 calves ≤10 d of age with expandable radiocollars during summer 2012 (n = 37) and 2013 (n = 34). We used known-fate analysis in Program MARK to estimate summer (15 May–25 Sep.) and annual (12 mo) survival for elk calves. The top model for summer survival was {S_{1–2wk,3–20wk}} indicating mortality during 1–2 wk of age and 3–20 wk of age best explained survival; overall probability of surviving 20 wk was 0.79 (95% CI = 0.68–0.88). For annual (12 mo) survival, model {S_birthweight} had the lowest AIC_c value indicating birth weight of elk calves best explained survival as heavier born calves had a higher probability of survival. The overall probability a calf survived to 12 mo of age was 0.75 (95% CI = 0.61–0.84). Cougar (Puma concolor) predation accounted for 81% of mortalities; remaining mortalities were from starvation (6.3%, n = 1) and unknown causes (6.3%, n = 1). Our results document high survival for calves likely due to productive habitats, an ecosystem-specific predator guild, and high alternative prey.

Ecological understanding of many arboreal and semi-arboreal species is limited because of difficulties associated with studying wildlife in canopies. As part of a multi-faceted Pinus strobus canopy research project, we used camera traps located in canopies to examine diel, seasonal, and spatial patterns of Peromyscus spp.'s arboreal habitat use. From 2014 to 2018, we documented 201 events of Peromyscus spp. using the canopy over the course of 8491 camera trap nights, at three separate sites spanning a 57 km north-south transect. We detected Peromyscus spp. at heights up to 24 m, the highest above-ground observation on record, for Peromyscus leucopus (white-footed mouse) or Peromyscus maniculatus (deer mouse), the two species of Peromyscus present within our study area. To determine species-specific canopy use, we live-trapped Peromyscus at the base of each research tree and applied differential markings; right ear tags for P. leucopus and left ear tags for P. maniculatus. Camera trap images revealed both species of Peromyscus climbed with peak activity between 2000 h and 0400 h. We found ∼90% of the camera trap events occurred in Aug., Sept., and Oct. which coincides with the maturing of P. strobus cones, suggesting Peromyscus spp. may seasonally exploit arboreal habitats to forage. Daily and monthly detection probabilities for Peromyscus spp. ranged from 0.15–0.70 and from 0.14–0.91, respectively. The probability of all three cameras failing to detect an individual Peromyscus spp., given it was present in the tree, on any given day or month, ranged from 0.15–0.19 and 0.01–0.06, respectively; indicating our examination of activity patterns was robust. Our observations challenge previous ideas of the arboreal tendencies of Peromyscus spp. and further expand our understanding of the natural history of these species within the arboreal realm.

Increasing activity levels permit greater food intake for use towards growth and reproduction, consequently increasing predation risk via increased detection. Larval anurans are models to examine activity level-predation risk tradeoffs, as they occupy a variety of lentic habitats that impose constraints on the distribution and abundance of species. Ephemeral ponds have a low abundance and diversity of predators and as a result tadpole species tend to have high foraging rates for rapid development. Permanent ponds generally possess a greater diversity and abundance of predators and tadpoles inhabiting these locations tend to have low activity rates or chemical defenses to minimize predation risk. The objective of this research was to examine how interspecific variation in activity level and response to predation risk, corresponds to the distributions of tadpole species along the hydroperiod gradient. Furthermore, we examined the intraspecific variation in activity level among the species. We conducted a series of laboratory experiments in which we quantified baseline activity patterns and the change in activity after the addition of a predator or exposure to alarm cues, for 12 species of larval anurans native to East Texas. Species that maintained a high activity level generally occupied ephemeral ponds and species that maintained low activity levels generally occupied permanent ponds. Only one species (Gastrophryne carolinensis) decreased their activity level in the presence of predator cues or conspecific alarm cues. These results highlight this tradeoff can have consequences on the life histories of multiple species, providing insight into how it affects the organization of ecological communities.

Limited survey data and numerous anecdotal accounts indicate the Common Nighthawk (Chordeiles minor) is experiencing population declines not only in Wisconsin, U.S.A., but across large parts of their range in North America. However, it is possible estimates from current avian monitoring efforts are not representative, because surveys are not necessarily conducted at dusk when C. minor are most active, nor do they specifically target urban areas where a portion of the C. minor population are known to nest on flat graveled rooftops. Therefore, urban crepuscular monitoring protocols are needed to address these issues, enhance current monitoring efforts, and gain a better understanding of C. minor demographics. In this study we used a citizen science-based methodology to survey 92 municipalities in southeastern Wisconsin in areas with varying degrees of urbanization to establish baseline data for this species that can then be compared to future counts. We investigated the influence of a range of environmental and ecological factors, as well as landscape features and land cover types in relation to C. minor occurrence. C. minor detection was positively correlated with Chimney Swift (Chaetura pelagica) counts, the number and area (m²) of flat graveled rooftops, and heavily developed land cover types. The surveys also revealed a negative correlation between agricultural land cover and C. minor occurrence. Overall, the use of citizen science to establish a baseline for C. minor was successful and may be adapted and applied to other crepuscular bird species at a broader geographic scale of similar landscape type.

Cooper's Hawks (Accipiter cooperii) nest commonly in various habitats throughout North America, but there are few comparative studies of the ecology of urban vs. rural nesting birds, especially regarding 1 y olds whose inexperience is purported to place them under different selective pressures than more commonly nesting hawks ≥ 2 y of age. Notably, selective pressures of cities have prompted recent changes in the life histories and phenotypes of urban birds, and some of these pressures may be age dependent. We investigated select intrinsic properties of individuals and reproductive output of breeding yearling females and their mates for potential differences in the ecology of urban vs. rural birds in Wisconsin, 1980–2017. We found no differences in mean body mass of yearling females, their male mates, nesting phenology, nor in average clutch or brood counts in urban vs. rural Cooper's Hawks. Excluding one instance, yearling females were mated to older males, ≥ 2 y of age, and within 33 pairs birds mated by like sizes (small/small, etc.). Sums of masses for paired birds were not correlated with their brood sizes, in contrast to our earlier findings on the same study areas where brood size was positively and significantly correlated with summed masses of paired birds ≥ 2 y old who also mated by similar size. We call for more comparative studies of Cooper's Hawks in cities < 100,000 people as studied herein, as most research on urban nesting Cooper's Hawks stem from large, metropolitan cities with about 1 million people, which are less prevalent than smaller cities as we investigated. Indeed, there is growing evidence worldwide that the types and strength of selective pressures on urban wildlife is greater in larger cities, yet less is known about small cities.

The Yazoo Darter Etheostoma raneyi is a small imperiled snubnose darter endemic to Upper Gulf Coastal Plain streams in north-central Mississippi. Installation of rip-rap and wood is being considered in an effort to increase suitable habitat and spawning substrate for the species. In common with other snubnose darters, Yazoo Darters attach their eggs to appropriate spawning substrate. However, it is not known if Yazoo Darters, or other imperiled Coastal Plain snubnose darters, will use rock substrate for spawning given it is almost entirely absent from streams of occurrence. If Yazoo Darters show no preference between wood and rock (rip-rap) for spawning, management would have greater flexibility when designing stream habitat installations for imperiled Coastal Plain snubnose darters, because the installation of rip-rap is much less expensive and time consuming than installation of wood. We used a randomized block experiment in an outdoor mesocosm facility to test for spawning substrate preferences. We counted >7600 eggs and Yazoo Darters used both substrates but used wood more than twice as often as rip-rap. Though we cannot recommend habitat installations using only rip-rap, any installation using a mix of wood and rip-rap will enhance spawning habitat for the Yazoo Darter and at least four other imperiled Coastal Plain snubnose darters.

Banded Killifish Fundulus diaphanus are considered a nearshore species closely associated with emergent or submergent vegetation in shallow calm waters. This species is commonly collected in nearshore waters of the Laurentian Great Lakes, usually along margins of coastal wetlands, beaches, drowned river mouth lakes, and slow-moving streams. However, in recent years (2015–2018) Banded Killifish have commonly been collected along the exposed, industrialized nearshore waters of Lake Michigan around the Calumet Harbor area (Chicago, IL). Individual specimens have been collected up to 2.8 km from shore and in depths up to 9.8 m in open waters of Lake Michigan. Capture of this species along hardened shoreline habitat, including rip-rap and steep drop-offs is also highly unusual for this small, littoral species and is not documented in the available literature. These observations provide an extreme example of habitat use by this littoral species and broadens our understanding of their habitat in nearshore waters of the Laurentian Great Lakes.

Clasping Warea (Warea amplexifolia) is a critically endangered plant species endemic to Florida. It is threatened due to habitat loss through urban development and poor land management, resulting in habitat fragmentation and small population sizes. To aid recovery strategies, information is needed on the genetic diversity among and within populations. We identified fourteen microsatellite loci that were polymorphic in W. amplexifolia and in the related W. sessilifolia, and nine loci that were polymorphic in W. cuneifolia. In W. amplexifolia, the number of alleles per microsatellite locus varied between four and 15, with observed heterozygosity in the range of 0.10 to 0.73. These newly identified markers will be used to inform recovery efforts for W. amplexifolia and may also be useful for studies of the population genetics of closely related taxa.