Tree-of-heaven (Ailanthus altissima) is an invasive species in North America that is becoming widespread in the eastern part of the continent. In the drier, western interior of North America, however, the spread of tree-of-heaven appears to be limited to areas where supplemental water is available such as in urban areas or in riparian environments. To explore the effect of summer drought on tree-of-heaven seedlings and to look for genetic variation for drought tolerance among half-sibling families, we collected samaras from 12 open-pollinated mother trees growing in Utah County, Utah, and measured the samaras' area, maximum width, length, and weight. We then planted 10 samaras per mother tree into 10-cm pots in the greenhouse, measured the height of each resulting seedling, and randomly assigned them to a watering treatment (well-watered or droughted) that lasted for 20 wk. We examined the relationship between tree-of-heaven samara size parameters and seedling height before we started our drought treatment and for additional growth parameters after our drought treatment. Several growth parameters (relative growth, final height, final dry mass, final stem dry mass, final dry root mass, and root-to-shoot ratios) were reduced significantly by drought but differed among seedlings from different mothers only for relative growth. There was no genetic variation for drought tolerance observed for any of the growth parameters. These results suggest that tree-of-heaven seedlings from this part of western North America are uniformly and negatively affected by drought and may explain the relative dearth of tree-of-heaven in the interior West.

Publicly owned lands designated as parks can be important tools for biodiversity conservation. In the U.S., state parks are afforded direct protection from localized development pressures, which may help to protect small, ecologically significant ecosystems such as isolated and ephemeral wetlands and headwater streams. We used the South Carolina State Park system as a case study to examine the structural and functional differences between small wetlands located inside vs. outside of parks in the Piedmont and Blue Ridge ecoregions in order to evaluate the efficacy of a small-scale conservation framework for protecting small, under-protected freshwater ecosystems. We evaluated data relating to water quality, wetland structure, and biodiversity parameters collected between January 2010 and June 2011. Our results indicated marked differences between park and non-park wetlands, with park wetlands having shallower depths, higher abundances of sensitive benthic macroinvertebrate taxa, and lower average tolerance values consistent with more sensitive macroinvertebrate species and higher water quality. These findings demonstrate that state parks can serve to protect freshwater ecosystems and biodiversity. State parks, thus, represent a preexisting network of protected areas to aid in the protection of localized habitats, such as small isolated and ephemeral wetlands, that may not otherwise receive the conservation protection warranted by their ecological function.

Due to grassland and prairie conversion for agriculture, milkweed species (Asclepias spp.) are now confined to small natural areas, agricultural fields, and marginal ecosystems (e.g., ditches and field margins). Monarch butterflies (Danaus plexippus) rely exclusively on milkweed and are in decline in part due to declining milkweed populations. We conducted a species distribution modeling exercise using MaxEnt to model milkweed species and common milkweed (Asclepias syriaca) presence in natural areas and ditches throughout northwest Ohio in order to identify which local or regional landscape attributes most strongly influence milkweed presence. We found that while natural areas and ditches have similar presence probability ranges (milkweed: natural areas 3–98% and ditches 1–98%; common milkweed: natural areas and ditches 0–98%), natural areas have a higher average probability of presence than ditches (milkweed: natural areas = 30 ± 26% and ditches = 7 ± 7%; common milkweed: natural areas = 22 ± 26% and ditches = 5 ± 6%). However, due to the large area covered by ditches and field margins in our study system, ditches and field margins with a probability of milkweed occurrence greater than the average probability of occurrence in natural areas encompass a larger total area than natural areas. We also observed that the presence of milkweed is positively correlated with the presence of shrub and C₄ grasses. We conclude that marginal ecosystems in ditches and field margins are an important component of regional milkweed and, thusly, monarch conservation by providing potential habitat across a diffuse network.

The horticultural trade is a well-known source of nonnative invasive plant species, yet urban and suburban developments are routinely planted with these species, creating high invasion pressure on adjacent natural areas. Understanding the spread of nonnative species and predicting invasions is critical for the management of natural habitats. Here, we examine the similarities in nonnative plant community composition between a remnant natural habitat at Fire Island National Seashore and the surrounding residential communities to assess the impact of nonnative invasive horticultural species on the natural area. In the natural area, we identified 16 locally listed invasive plant species. In residential areas we identified 21 locally listed invasive species. Of 162 properties surveyed, 144 appeared to be occupied and maintained by residents; 18 appeared unmaintained or abandoned. Unmaintained properties had significantly more invasive species than maintained properties. Nonnative species composition between the natural and residential areas was not significantly different. In the natural area, distance from suburban edge, native species richness, and soil moisture were important drivers of invasion. We show that in this particular natural area, invasive plants have not invaded farther than 25 m into the forest, indicating the strong role of edge effects in invasions. Additionally, we show that unmaintained properties in the residential areas may be the primary source of invasives to natural area. Homeowner education on the impacts of invasive species and active management of the nonnative invasive species in the unmaintained properties may be important for preventing further invasions to the forest.

With the substantial losses of native prairie habitat over the last century, research focusing on the restoration of prairies has become imperative in order to conserve these imperiled ecosystems and the biodiversity they support. On the Clatsop Plains in northwestern Oregon, there are only a few remnant patches of coastal prairie, which are vital for many species including the federally threatened Oregon silverspot butterfly (Speyeria zerene hippolyta). Building upon previous work done on the Clatsop Plains, we implemented a study to develop techniques to improve coastal prairie restoration in this region. The objective of this study was to identify an effective site preparation/treatment that resulted in the greatest success of seeded forb and graminoid establishment, while also limiting introduced graminoid and forb species. We examined the effectiveness of four treatments (untreated control, herbicide, soil inversion, and soil removal) at three sites on the Clatsop Plains. After three seasons, the soil removal treatment enhanced native species abundance while maintaining low cover of introduced forbs and graminoids. However, cost of these methods is also an important consideration for land managers. Soil removal was the most effective treatment we tested, but it would be more expensive to implement on a large scale compared to the other treatments.

Fens are rare and not well-studied within the Prairie Pothole Region (PPR) of North Dakota. PPR wetlands (including fens) are vulnerable to land use alterations, particularly conversion to agricultural production. In this study, we described a 48-ha natural fen complex with five distinct wetland plant communities (denoted cattail [Typha L. spp.], floating mat [areas at higher elevation with an upward groundwater gradient], herbaceous, tree, and wet meadow). Our goal was to describe the wetland plant communities and determine possible factors driving the formation of several distinct wetland plant communities in close proximity to one another. We identified 148 plant species, six of which are considered priorities for conservation by the North Dakota Natural Heritage Program. We compared the composition of wetland plant communities using multi-response permutation procedure (MRPP) and examined individual attributes (e.g., species richness, evenness, diversity, Floristic Quality Index, percent introduced species, percent soil organic matter, pH, and electrical conductivity) of the wetland plant communities using ANOVA and Tukey's (HSD) test. We found the highest species richness, evenness, and diversity in herbaceous and tree communities and the lowest percent introduced species in floating mat communities. There were no significant differences in the soil properties tested among the five plant communities.

Wildfires on public lands in the United States are increasing in size and frequency over time. Government agency post-fire treatments often include seeding of native and nonnative plant species; however, the effectiveness of post-fire seeding has been questioned, and while the importance of using native species has been emphasized, more research on the effects of native seeding post-fire is needed. We sought to understand what characteristics of vegetation communities distinguished burned and unburned areas, and if environmental characteristics of sites would predictably alter community composition. We collected vegetation, ground cover, and environmental data during the summer of 2015 from public lands that burned in wildfires between 2005 and 2012 and were seeded with a native seed mix. We also collected data from unburned comparison areas that were not seeded. We found that biological soil crusts distinguished unburned areas while native forbs, nonnative forbs, and seeded native species distinguished burned areas. Surprisingly, Bromus tectorum (cheatgrass) was not important in distinguishing burned from unburned areas. Precipitation the year after fire influenced vegetation communities.

In Chile, most protected areas are located in the southern Andes, in mountainous landscapes at mid or high altitudes. Despite the increasing proportion of protected areas, few have detailed inventories of their biodiversity. This information is essential to define threats and develop long-term integrated conservation programs to face the effects of global change. Consequently, the objectives of this study were to (1) describe the richness, conservation status, and species composition of the vascular flora found in Bosque Pehuén Park; and (2) analyze the relationships among altitude, species richness, and growth forms. Bosque Pehuén is one of the largest privately protected areas located within the Araucarias Biosphere Reserve, in southern Chile (39°S). The park is dominated by secondary forests that grew after intensive exploitation in the 1970s, with some remnant old-growth forests. Fifteen regularly distributed plots, 150 m in radius, were sampled. At each plot, all vascular plant species were recorded; 101 species were found, of which 79% are endemic, 10% are introduced, and 13% are currently listed in IUCN conservation categories. The highest richness was concentrated within the plots associated with riparian zones. The total richness tended to decrease with altitude. Epiphytes and climbers were only recorded at lower altitudes, making them the growth forms most influenced by altitude. The background information reported here is essential for effective park management and conservation of the vascular flora species found within this Andean montane forest.