The purpose of this study was to examine the characteristics of riparian plant communities along a gradient of livestock exclusion in the Lower Columbia River Basin (LCRB) located in the Pacific Northwest region of the United States. Livestock exclusion from riparian wetlands is a common passive restoration technique. Few studies, however, have focused on the effects of livestock grazing or the exclusion of livestock grazing on these ecosystems. Vegetation community composition was examined in two passive restoration sites, three and 13 years since livestock exclusion, and in a reference site with continued livestock grazing. We hypothesized native plant species richness would be lower in the excluded wetlands than in the grazed wetland due to the competitive exclusion from an increase in non-native plant dominance in the absence of grazing. The grazed wetland had significantly (P < 0.02) greater mean total species richness (23.3 ± 1.6; mean ± 1 standard error), native (10.2 ± 0.5), and non-native (12 ± 1.5) species richness than both the excluded wetlands. Mean total species richness did not differ significantly (P = 0.088) between the three-year (12 ± 1.4) and 13-year (5.5 ± 2.3) excluded wetlands. Mean native and non-native species richness also did not differ significantly (native P = 0.088. non-native P = 0.064) between the three-year (native 6.3 ± 0.6, non-native 5 ± 2.3) and 13-year (native 2.8 ± 1.3, non-native 2.7 ± 1.1) excluded wetlands. However, native species abundance as indicated by percent cover was significantly (P < 0.02) lower in the 13-year excluded wetland (4.2 ± 2.0%) than both the three-year excluded (51.5 ± 3.9%) and grazed (23.2 ± 3.3%) wetlands. The invasive grass, Phalaris arundinacea (reed canarygrass), was found to be the dominant vegetation cover in all three wetlands, with average relative cover ranging from 95.2 ± 2.0% at the 13-year exclusion site to 52.8 ± 4.1% at the grazing site, and 43.0 ± 4.0% cover at the three-year exclusion site. These observations suggest that livestock exclusion alone may be an ineffective strategy for restoring riparian plant communities in regions such as LCRB where invasive species like reed canarygrass are abundant. More effective management alternatives might include short-term livestock exclusion and reintroduced targeted grazing to both reduce livestock impacts and control reed canarygrass dominance.

The proximity of urban green spaces to anthropogenic food sources can promote high densities of predators that may negatively affect breeding birds. Not only can high numbers of predators depress reproduction and survival, but birds may behaviorally respond by avoiding those patches, thereby diminishing the value of urban habitats. During 2010 and 2011, we examined relationships between avian territory density and activity of nest predators in 36 2-ha plots within six urban grassland and early successional parks (sites) near Chicago, Illinois. At the plot (i.e., local) scale, densities of common yellowthroats (Geothlypis trichas), field sparrows (Spizella pusilla), and savannah sparrows (Passerculus sandwichensis) were more strongly linked to habitat characteristics than predators. Song sparrow (Melospiza melodia) and eastern meadowlark (Sturnella magna) densities were not associated with habitat at the plot scale, but together were negatively related to activity of avian predators. Surprisingly, densities of song sparrows were positively associated with snake activity at both plot and site (i.e., landscape) scales, and densities of savannah sparrows increased moderately with activity of mesopredators at the site scale. Our results suggest that although habitat structure is a strong predictor of grassland bird densities in this urban matrix, activity of predators also may contribute to patterns of territory selection of certain bird species. With this in mind, managers encouraging settlement of grassland birds within urban preserves may consider (a) increasing dense groundcover that provides protective cover for songbirds, and (b) discouraging activities that promote activity of avian predators, particularly corvids.

Cross Timbers forests of south-central North America contain large expanses of relatively undisturbed old-growth forest where gap-phase regeneration is the main mode of canopy replacement. These forests are threatened by fire suppression, overgrazing, invasive species, global climate change, and urban development. To characterize dynamics of stand development and learn whether canopy trees lost in tree-fall gaps were being replaced by trees of the same species, we conducted a study of tree-fall gaps and their regeneration in three widely separated Oklahoma Cross Timbers forests. Eleven species were found in the forest canopy and three species dominated: post oak (Quercus stellata) (76%), blackjack oak (Q. marilandica) (7%), and black hickory (Carya texana) (10%). Although gaps were small (13–30 m²) resulting from the death of one to two trees, regeneration did not appear to depend on gap size. There was abundant regeneration even in the understory of the closed canopy; most likely much of it was sprouts of dominant species stimulated by burning. Regeneration was very slow, apparently due to drought, which may have been so limiting as to reduce the benefit of gaps. There was no evidence that canopy species composition was on track to change, as the most common canopy tree species whose deaths resulted in a gap, were also the most common tree species regeneration to fill the canopy gap.

Predispersal seed predation can be detrimental for any plant, but especially for rare plants. In this study, we examined the relationship of predispersal seed predation to different habitat types (i.e. open, semi shaded, and shaded), population size, and population density for Synthyris bullii, a rare Midwestern US endemic plant. In 2009, 2010, and 2011, a total of 18 populations were sampled across the range of Synthyris bullii. Fruit damage and predispersal seed predation were determined from up to 20 randomly collected infrutescences from each population. Predispersal seed predation had an impact on reproductive output and varied by habitat type. In addition, predispersal seed predation varied by population size and population density. Understanding the effects of predispersal seed predation on rare plants can be crucial for maintaining stable populations and developing better conservation and management strategies.

Poor regeneration of some species of oaks (Quercus spp.) within undisturbed closedcanopy forests is common throughout much of the eastern United States. Oak regeneration failure is often inferred from negatively skewed size-class distributions, but evidence of replacement by non-oaks requires investigation of changes in composition and size distributions. I examined how tree species composition and the log-transformed diameter distributions of oaks and non-oaks changed between 1999 and 2013 in an old-growth forest on the University of Mississippi campus. There was a general weak trend towards replacement of oaks by non-oaks. Oaks showed nonskewed or negatively skewed diameter distributions in 1999 and 2013. Diameter distributions of southern red oak (Quercus falcata) became significantly more negatively skewed, and the abundance of this species declined. However, there was no significant change in skewness of diameter distributions of the more fire-tolerant but longer-lived post oak (Q. stellata) and no significant decline in its abundance. Diameter distributions of trees of mockernut hickory (Carya tomentosa) became significantly more positively skewed, as it increased in abundance due to high recruitment and survival. In contrast, there was no significant change in diameter distributions in sweetgum (Liquidambar styraciflua) despite high recruitment, due to significant mortality of medium-sized trees of sweetgum. In addition to differences in fire tolerance between oaks and non-oaks, this study shows that differences in survival and longevity are important predictors of future species composition and that fire tolerance is not synonymous with early-successional status.

An appreciation for the importance of structural complexity, combined with the acknowledgment that stands with complex structures are uncommon compared to pre-European settlement estimates, has led to a growing interest in restoring late-successional forests. The success of these projects is dependent upon our understanding of the variability of late-successional structure and the disturbance events that produced this structure. We quantified woody species composition, stand structure, canopy disturbance history, and Quercus establishment and canopy accession patterns to document processes that resulted in the structural conditions of an upland hardwood forest in Tennessee. The forest established in the mid-1800s and exhibited structural characteristics that were within the range of what has been reported from other late-successional forests in the region. The forest overstory was dominated by Quercus prinus, but Acer saccharum was the most abundant species. Quercus recruitment was continuous from stand initiation through the 1950s. The vast majority of Quercus trees that established prior to 1880 established in closed canopy conditions, whereas most Quercus trees that established after 1880 established in high light environments. Quercus establishment in canopy gaps resulted in multi-aged Quercus populations in the forest. We documented three forest-wide disturbances during development (1922, 1945, and 1973). The 1922 forest-wide disturbance coincided with an establishment pulse of largely understory taxa, and the broad-scale event of 1945 corresponded with an establishment pulse of A. saccharum. Our results provide benchmarks for a region that lacks other reference conditions and can be used to inform structure and process based restoration approaches.

Liriope spicata is a low-growing, grass-like perennial that is native to Southeast Asia. This and several similar Liriope species have been widely introduced into the United States for ornamental and groundcover purposes. Liriope spicata can spread aggressively via seed dispersal and creeping rhizomes and form dense, monotypic patches. Little information is currently available in the literature concerning creeping lilyturf control. We tested seven herbicides in 2011 and 2012 using container grown creeping lilyturf that had been established for approximately one year prior to treatment. Visual evaluations at 30 and 60 days after treatment indicated that no treatment provided rapid control of the foliage. However, above- and belowground biomass harvested at 90 and 180 days after treatment (DAT) indicated that metsulfuron and imazapyr were highly effective in controlling L. spicata. Both herbicides reduced belowground biomass by greater than 97%. Glyphosate and imazapic, which have been recommended for creeping lilyturf control, only reduced belowground biomass by 43 and 45%, respectively, at 180 DAT. The herbicides 2,4-D and dicamba, which have known efficacy on other members of the family Liliaceae, did not effectively control L. spicata. These results indicate that metsulfuron and imazapyr are more effective treatment options for creeping lilyturf control than currently recommended glyphosate and imazapic treatments. However, in hardwood forest systems where creeping lilyturf is primarily invasive, their utility may be limited due to potential nontarget damage.

Chinese tallow tree (Triadica sebifera) is arguably one of the most deleterious exotic invasive plants in the southern United States, where it alters ecosystem structure and function, especially near the Gulf Coast. Chinese tallow continues to expand into riparian floodplain forests, which likely facilitate regional invasion by dispersing seeds during seasonal flooding and providing corridors of favorable habitat. We attempted to estimate existing Chinese tallow soil seedbank presence and density in a bottomland hardwood forest located at Old Sabine Bottom Wildlife Management Area (OSBWMA) in northeastern Texas, where heavy infestation has not occurred to date, though mature seed-bearing trees are present regionally. No Chinese tallow seeds were detected across the study area, despite the occurrence of mature, seed-bearing plants on adjacent properties. Based on this lack of detected seeds, combined with the lack of observed Chinese tallow plants at OSBWMA, it appears the species continues to occur at low densities within apparently suitable habitats in northeastern Texas, perhaps reflecting a lack of en masse water-mediated dispersal into the region due to its upstream location in relation to heavily infested areas further south.

Japanese stiltgrass (Microstegium vimineum) is an annual grass native to parts of Asia that has invaded many areas around the world. We conducted a study in Catoctin Mountain Park in Thurmont, Maryland, to determine if low rates of the grass-specific herbicide Sethoxydim were as effective as the label rate for spot treatment (1.5–2.25%) against M. vimineum. Sethoxydim E Pro was applied at 0.75%, 1.0%, and 1.5%. Treatments occurred in July 2011, 2012, and 2013. In September of 2011, 2012, and 2013 all treatments had reduced the cover of M. vimineum relative to the controls and there was no significant difference between the three treatments or the three groups of plots and no significant effect on other species. In July 2014, M. vimineum cover had rebounded substantially and by September 2014, cover of M. vimineum in treated plots was not significantly different from the controls.

The conservation and management of wildlife species is contingent on estimating distribution and abundance. Sampling of wildlife requires repeated visits to accurately determine species occurrence and to quantify abundance across temporal and spatial scales. The use of trails to sample wildlife populations is increasing and offers opportunities to potentially sample more frequently, with increased ease of access, and less disturbance to habitats, which can be important in sensitive natural areas. We examined capture data of terrestrial salamanders within Great Smoky Mountains National Park to determine if detection and abundance estimates from trail and non-trail transects were significantly different. Across two, 3-week periods during June and July 2012, we sampled 195 transects (70 along trails and 125 within non-trail habitat) on multiple occasions. We found that most microhabitat variables associated with salamander detection and abundance did not differ between trail and non-trail transects. Further, our models indicate detection and abundance of terrestrial salamanders were not significantly different on trail and non-trail transects. These results suggest trails can be used to accurately estimate abundance of terrestrial salamanders and may reduce the need to sample for plethodontid salamanders in sensitive habitat.

In 2012, cleared floral organs of Mead's milkweed, a federally threatened species, were found to contain fungal hyphae. All fresh flowers (n = 10) collected and analyzed from Rockhill Prairie (Missouri) contained Metschnikowia spp., Cladosporium cladosporiodes, Alternaria spp., Thanatephorus sp., Aspergillus sp., and Cryptococcus sp. Of the ten fresh flowers collected from the Anderson County Prairie Preserve (Kansas), 90% (n = 10) of the flowers contained fungi, including C. cladosporiodes, Alternaria spp., and Metschnikowia spp. A dried stem collected from the Anderson County Prairie Preserve revealed the presence of Fusarium spp., Alternaria spp., Metschnikowia sp., Lewia infectoria, Stemphylum solani, and Filobasidium floriforme. In addition, we analyzed pinned insects (n = 13) captured previously over a three-year period. These insects were all caught while they foraged on flowers of A. meadii. The fungal genus, Alternaria, was the only fungal taxa isolated at least once from our samples of flowers, dried stems, and some anthophilous insects.

The thermal wetland on The Nature Conservancy's River Fork Ranch in northwestern Nevada hosts 51 seeps and springs on 0.81 ha and lies atop a fault line at the base of the Sierra Nevada Mountain Range. In this note, we report on floral and faunal surveys and make recommendations for the restoration and management of this site as part of the larger preserve.