Forests with an old-growth Pinus strobus (white pine) component are rare in the Upper Midwest. I established 9.5 ha of permanent plots at five sites in mature mixed forests of northern Wisconsin and Upper Michigan to study late-successional dynamics, with emphasis on P. strobus demography and reproduction. This manuscript includes the first description of this network of permanent plots, the data of which are archived for potential use by forest managers and ecologists. Pinus strobus exhibited a variety of size distributions within 13 plots, indicative of its versatile role in stand composition and succession. Three plots exemplified a “classic” unimodal P. strobus size distribution of large emergent trees within an old-growth mixed stand. However, most plots contained an atypical bimodal distribution of P. strobus, consisting of saplings and large trees. Other plots approximated a negative exponential curve of continual recruitment or exhibited an influx of P. strobus saplings into hardwood-dominated stands. The recent P. strobus reproduction may indicate a reversing successional trajectory from hardwoods to P. strobus, which is opposite to reported regional trends of mesophication or mapleization in these mixed mesic forests. Differential deer browsing that inhibits hardwood regeneration is hypothesized as a driver for this counter trend. Overall, the 13 plots illustrate the ecological breadth of P. strobus and suggest a complexity of successional patterns.

Globally, savanna trees experience bottlenecks to recruitment. Likelihoods are low that juveniles, especially of nonclonal, reseeder species, will survive and reach sizes that survive recurrent fires. We hypothesized if ground layer vegetation within savannas contained patches with reduced fire effects, likelihoods of juvenile trees surviving fires would be increased. We refined our general hypothesis based on a field study in an old-growth southeastern pine savanna of North America, in which longleaf pine (Pinus palustris Mill.) is the most abundant tree. We hypothesized that recruitment of pines into the fire-resistant ‘grass stage’ may be more likely in three ground layer microhabitats (inside crowns of fallen pines, around pine tree stumps, and inside patches of oak/hardwood stems) than in surrounding groundcover located away from overstory pines. We measured the composition and abundance of ground layer vegetation and censused juvenile grass stages (< 1.5 m height) of longleaf pine in plots in replicated patches of these three microhabitats and in the surrounding ground layer matrix, all located away from large trees. Ground layer vegetation was less abundant inside than outside the three microhabitats and abundances of grasses and shrubs differed among microhabitats. A zero-inflated Poisson model indicated that occurrence of grass stage longleaf pines was >5 times more likely inside the three microhabitats than in the surrounding ground layer matrix. Recruitment was also more likely in pine than oak/hardwood microhabitats. We propose that altered microhabitats, especially those generated by death of large longleaf pines, likely facilitate recruitment into populations of this reseeding savanna tree.

The small white lady's-slipper, Cypripedium candidum, is a rare perennial orchid with a limited distribution in Canada, occurring as isolated populations in remnant tallgrass prairie in southern Manitoba and Ontario. The species is listed as endangered in both provinces and as threatened federally. Despite its status, information on how environmental conditions and land management affect population size and persistence of this species is limited. We used 20 y of monitoring data collected for a subset of the largest population in Canada to evaluate the response of small white lady's-slipper to land management and weather. Long-term monitoring suggests the population is in decline and may not persist under the current climate and management regime. Temperature appears to regulate vegetative growth and flowering proximately. Warm temperatures early in the spring, when shoots are emerging, appear favored, but high temperatures during anthesis appear detrimental, reducing both vegetative growth and flowering. In contrast, precipitation appears to have a lag effect on growth and flowering. However, snow depth was identified as a positive influence on vegetative growth, suggesting precipitation in early spring, when shoots are emerging, is also important for above-ground growth. Some grazing appears to benefit the species presumably by reducing competition and shading, but frequent grazing may increase the risk of direct damage to individuals from cattle consumption and trampling and does not provide sufficient time for individuals to recover following grazing events. Our findings add to the knowledge of orchid conservation and management, highlighting the importance of long-term monitoring in detecting population trends in species with erratic life cycles and fluctuating populations, such as the small white lady's-slipper.

Helianthus eggertii is a rare perennial sunflower of barrens and open habitats in Kentucky, Tennessee, Alabama, and South Carolina in the United States (U.S.). Despite its delisting in the U.S. Endangered Species Act in 2005, little is known about the germination biology of H. eggertii other than seeds require cold stratification for optimal germination. Knowledge about the germination biology of rare species can aid in the management of natural populations and inform strategies for ex situ seed conservation and propagation. We examined how cold stratification, light, and temperature interact to affect seed germination in H. eggertii, and whether germination proportions varied among populations. At the time of maturity in October, seeds have primary physiological dormancy and require cold stratification or prolonged (> 8 wk) incubation in light at cool (15/6 C) temperatures to germinate. Seeds maintained a light requirement for germination when cold stratified in darkness, but not after cold stratification in light. However, seeds germinated to lower proportions after cold stratification in light relative to darkness, and when incubated at temperatures that mimic summer (35/20 C) compared to late spring (25/15 C). Germination varied widely among populations (23-58%), with plants from more open sites exhibiting lower germination proportions than those from partially shaded sites. Our results indicate seeds most likely germinate in early- to mid-spring, and light promotes germination of H. eggertii. Our results highlight the interactive role of light and temperature in determining seed dormancy break and germination in H. eggertii.

The regal fritillary, Speyeria idalia (Drury), was once a common inhabitant of North American grassland communities. Regal fritillary populations are commonly reported to have a male biased adult sex ratio (ASR) throughout their range. We assessed the observed ASR of regal fritillary throughout an annual flight period, investigated how the overall density of both sexes changed, and tested effects of prescribed fire, grazing and haying management treatments on male and female density. We found that regal fritillary exhibited an observed 2:1 male biased ASR across the entire emergence period. Our analysis also revealed that male density peaked earlier than female density in the flight period. Point estimates of density indicated sites that received prescribed burning at the moderate fire-return interval supported ≥1.3 times greater density of males and ≥5.6 times greater density of females versus sites burned with short and long fire-return intervals. Additionally, this effect was enhanced when combined with grazing which showed males were ≥1.9 times and females had ≥1.2 times greater point estimates of density in sites that were grazed and burned at a moderate fire-return interval versus other sites. The relatively stable status of regal fritillary within our study region suggests that a 2:1 male to female ASR may be considered the model composition of populations throughout their range. Likewise, the dynamic nature of the ASR throughout the flight period highlights the importance of conducting surveys across the flight period. Finally, these results corroborate an increasing number of research results that reveal common prairie management practices, such as prescribed fire can be applied within sites that contain regal fritillary and continue to support stable populations.

Population declines of birds affiliated with grasslands and grass-shrub habitats have been identified as a critical conservation concern. The effects of woody encroachment into grassland-dominated systems, which may contribute to species declines, has been examined mainly in upland systems. We examined occurrence of bird species across a gradient of graminoid- to shrub-dominated wetlands in the Upper Peninsula of Michigan and describe the habitat characteristics associated with their probability of occurrence at segment (100 × 100 m) and landscape (200 m buffer) scales. Because fire can suppress woody encroachment, we also examined the role of fire history, extending from <1 to >50 y on birds and habitat characteristics. We focused on seven species closely affiliated with grassland and grass-shrub habitats, but also found in wetlands: Sedge Wren (Asio flammeus), LeConte's Sparrow (Ammodramus leconteii), Savannah Sparrow (Passerculus sandwichensis), Bobolink (Dolichonyx oryzivorus), Common Yellowthroat (Geothlypis trichas), Swamp Sparrow (Melospiza georgiana), and Alder Flycatcher (Empidonax alnorum). We used nonparametric, multiplicative regression models to relate habitat variables and fire history to probability of species occurrence. Unlike studies in upland grasslands, none of the top models included measures of litter or graminoid height, and the highest probability of occurrence often was where graminoid cover was at intermediate rather than highest levels. Measures of woody cover or structure were important to all seven species modeled. We observed few clear differences in habitat metrics across fire history categories beyond the first year of burning. Years since last burned was in the best model for four of the seven species, despite high variability of habitat metrics within fire history categories; those species were more likely to occur in segments burned 15–19 y earlier. Infrequent light- to moderate-severity fires in fens had little effect on focal species occurrence beyond the first year after burning and little long-term effect to suppress woody cover.

Wolverines (Gulo gulo) were nearly eliminated from the contiguous U.S. by the mid-1920s, when they began to naturally recolonize portions of their historical range. Currently, the Greater Yellowstone Ecosystem in Wyoming represents the southernmost distribution. Using remote cameras, we detected two female wolverines in 2016 and 2017 in Wyoming, originally captured as juveniles. At nearly 11 and 12 y old, both were documented in the same areas where they appeared to set up home ranges previously, suggesting continued residency. The presence of long-lived females near the southern boundary of recolonization is important to the persistence of residents as well as population expansion. However, nearest habitat to the south is ≥130 km across open land atypical of wolverine habitat. Connectivity between island-like patches of habitat will be critical to continued recolonization, although active restorations may still be needed in areas unlikely to receive females through natural dispersal.

Water management structures (WMS) are used to regulate water levels between large floodplain river backwaters and their adjacent river systems offering a balance between maintaining quality backwater habitat and providing benefits to the river systems. The design and operation of these WMS is dependent on unique management goals, and their impacts on the surrounding ecosystem are understudied. From 2016–2018 we quantified the response of the surrounding fish assemblages (i.e., backwater and river abundance and composition) to the WMS operation at the Emiquon Preserve, a 2723 ha restored floodplain lake located adjacent to the main channel of the Illinois River, U.S.A. Environmental conditions were recorded, and fish were collected using boat electrofishing on both sides of the WMS under three operational levels: closed and no flow, gravity flowing water, and mechanically pumping water to the river. Multivariate analyses determined that there was no difference in fish community composition within the Emiquon Preserve among operation levels. Within the river there were differences in community composition when the WMS was closed and mechanically pumping water. Environmental parameters varied seasonally and WMS operation level varied but indicated an increase in chlorophyll-a in the river when the WMS was mechanically pumping water, although the chlorophyll-a decreased within 200 m downstream of the WMS in the Illinois River. This study suggests that managed connections between restored backwater and habitats operated like this WMS have variable, spatially isolated impacts on fish communities despite supplying chlorophyll-a to large river ecosystems.

Birds in the family Caprimulgidae generally exhibit high nest site fidelity, but it is not known if fidelity extends to foraging sites, especially for Common Nighthawks (Chordeiles minor), which are otherwise one of the most studied species. Common Nighthawks are ecologically distinct from other caprimulgids, being one of the few true aerial hawking species and among the longest distance migrants in the group. We predicted these birds would exhibit fidelity between years to a foraging site in British Columbia, Canada, where they forage in large numbers on a nightly basis and the same individuals return nightly. We banded individuals and, for a subset of birds, attached transmitters programmed to activate upon return to the foraging area the next year. We estimate we marked approximately 10% of the birds foraging at the site, but did not recapture a single marked bird despite capturing potentially 50% of birds foraging at that site over the two subsequent years. Furthermore, we did not detect any of the subset of birds with radiotransmitters, indicating they did not return to the foraging site in the year following initial capture. Our data suggest low fidelity between years to a foraging site, in contrast with the published records for nesting by this species and with the general expectations for the group.

Baylisacaris procyonis is a roundworm that is tolerated by its primary host, raccoons (Procyon lotor). However, this roundworm can be fatal to intermediate mammalian hosts and may be a contributing factor to population declines of the endangered, Allegheny woodrat (Neotoma magister). We used fecal flotation to determine the prevalence of B. procyonis eggs in raccoon scat found in locations that overlap with where woodrats persist in the mid-Atlantic. We determined that B. procyonis was present at two extant woodrat colonies in Maryland and Pennsylvania. We expect woodrat populations at these sites to decline, if the roundworm and other factors (e.g., forest fragmentation) are not alleviated.