Fire history studies are important tools for understanding past fire regimes and the roles humans played in those regimes. Beginning in 2010, we conducted a fire history study in the Pine Creek Gorge area of north-central Pennsylvania to ascertain the number of fires and fire-free intervals, their variability through time, and the role of human influences. We collected 93 cross sections from fire-scarred red pine (Pinus resinosa) snags, stumps, and living trees at three separate sites along the western rim of Pine Creek Gorge. From these, we found 79 fire years and 11 multidecadal fire-free intervals between 1600 and 2010. The three fire histories were quite synchronous; their fire years and fire-free periods mirrored one another despite being 12 to 14 km apart. Before 1791, fires were rare, suggesting a low population of American Indians and (or) little woodland burning by the tribes. A prolonged fire-free interval from 1650 to 1735 coincided with the Beaver Wars and the introduction of European diseases. Another fire-free period coincided with the American Revolutionary War. After that, fires became quite common with nearly all of them occurring within the next 125 years while Pine Creek Gorge was intensively logged. Since logging ended and fire control started in the 1910s, fires have been virtually absent from the three sites. Based on the fire and human histories, we conclude that human activities and culture are the driving forces behind the fire regimes of Pine Creek Gorge.

Ecological disturbances structure plant communities. In areas where reintroducing natural disturbances is unfeasible, land managers use artificial disturbances, such as fire and mowing, to simulate natural disturbances. However, prescribed fire and mowing can promote or inhibit seedling survival in plant populations. Lupinus perennis (the wild blue lupine) is a potentially threatened species commonly subjected to rotations of burning and mowing treatments to restore habitat for endangered butterflies (e.g., Karner blue, Lycaeides melissa sameulis). While L. perennis adults respond favorably to these management techniques, it is unknown how these variable management programs affect natural seedling recruitment and establishment. We quantified natural L. perennis seedling survival in seven managed remnant oak savannas in Northwest Ohio in 2007 and 2008. To evaluate the roles of management history and environmental factors on recruitment, we obtained burning and mowing management records for each savanna, measured environmental variables at each seedling, and assessed their relationships with seedling mortality. Seedling survival varied among the savannas and increased with greater fern and grass stems, moss cover, soil moisture, and initial size, but was reduced by increased oak saplings, light levels, and topographic wetness. Site elevation and initial seedling size affected the sizes of the juvenile plants. Management activities did not directly influence seedling survival or density, but the number of fires and total management activities at a site were positively correlated with oak saplings, suggesting current management practices may indirectly reduce lupine survival. Future management strategies may increase recruitment by focusing on the restoration of multiple species that are important components of the lupine regeneration niche.

A decline in Lake Erie water levels in 2000 from historic high levels of the 1990s has facilitated a shift in coastal wetland vegetation from open-water floating-leaf plant communities to emergent communities often dominated by the invasive perennial grass, Phragmites australis. Dense, near monotypic stands of this grass may lead to the loss of native plants and reduce suitable habitat for waterfowl and other wetland birds. To assess avian response to this shift in plant community structure, we conducted bird surveys (June–August, 2007) across four vegetation types in two coastal wetlands in the western basin of Lake Erie. Phragmites habitat had higher overall bird abundance but contained the lowest species diversity (H' = 0.71) of the four habitat types. Of the 35 species observed across habitat types, 4 species: (1) red-winged blackbird (Agelaius phoeniceus); (2) tree swallow (Tachycineta bicolor); (3) barn swallow (Hirundo rustica); and (4) bank swallow (Riparia riparia), accounted for 94% of total bird abundance. Ninety-four percent of all birds observed in sampled plots of Phragmites were red-winged blackbirds, and 73% of the total bird abundance (all species) across habitats occurred in Phragmites. This was mostly attributed to the large roosts (>500 birds/50-m radius plot) of red-winged blackbirds in sampled plots of Phragmites. Phragmites community overlap (R_o), represented by Horn's index, varied from a low of 0.30 with floating-leaved vegetation to a high of 0.69 within the Typha (cattail) community. Our results suggest that Phragmites does influence bird abundance and species diversity, but caution is warranted without additional data on nest success and survival.

Western prairie fringed orchid (Platanthera praeclara) populations may be highly variable over time. It is thought that soil moisture, and potentially disturbance, play important roles in determining abundance and flowering in this species. We present data for a P. praeclara population in southwestern Minnesota that has been monitored annually for 20 years. The number of flowering orchids varied over this period from 0 to 722. We provide an empirical test of an earlier model of precipitation effects during phenological life stages of the orchid, finding that the model was no better than a simple null model that ignored variability in precipitation. We re-examined the relationship between number of flowering orchids and precipitation during phenological life stages based on a modern information theoretic (AIC), multimodel inference approach, and a larger data set. The models indicate the importance of precipitation during three phases of orchid life history: (1) mature growth in the previous year; (2) postsenescence; and (3) emergence, explaining >70% of the variation in the number of flowering orchids. We also evaluated the effect of prescribed burns on this orchid population. Although we found no effect of fire on the number of flowering orchids, plants were shorter in burn years. This difference was not significant, however, once variation in precipitation was taken into account.

Research was conducted on control methods for Oriental bittersweet (Celastrus orbiculatus), pale swallow-wort (Cynanchum rossicum), and Morrow's honeysuckle (Lonicera morrowii) near Long Island Sound in Groton and East Lyme, Connecticut. These nonnative, invasive plants threaten the health of ecosystems at these sites and many other areas throughout the Northeast. For the Oriental bittersweet study, vines were treated at one of three timings (April, August, or November) in 2003 and evaluated in the summer of 2004. Treatments consisted of triclopyr ester formulations applied to the basal bark of uncut vines, or of triclopyr amine or glyphosate formulations applied to the stump surface of cut vines. The experiment was repeated with a different set of vines treated in 2004 and evaluated in 2005. Cut-stump herbicide treatments were generally more effective than basal-bark treatments at killing bittersweet vines. All cut-stump herbicide treatments were effective in reducing vine survival and number and length of sprouts. Pale swallow-wort plots were established in areas of high infestation near the shore. Treatments applied in July 2003, and again in August 2004, included hand pulling, cutting, application of glyphosate or triclopyr amine to cut stems, or foliar sprays of glyphosate or triclopyr amine. By July 2005, glyphosate foliar sprays and cut-stem treatments with glyphosate or triclopyr caused the greatest reduction in the amount of swallow-wort, and the glyphosate treatments were most effective in reducing swallow-wort vigor. Triclopyr foliar sprays injured swallow-wort, but long-term control was not better than that provided by annual hand pulling, cutting, or no treatment. For Morrow's honeysuckle, herbicide treatments were applied to freshly cut stumps in August 2005, and were evaluated in May 2006. Treatments consisted of glyphosate, triclopyr amine, or triclopyr ester, each applied at low or high doses. All triclopyr treatments reduced the number and length of sprouts, and both glyphosate treatments completely prevented sprouting from honeysuckle stumps. Our study provides land managers with effective control methods for three highly invasive plants.

Recreational trails are an agent of anthropogenic disturbance in nature reserves and other low human impact areas. Effective management must balance the desire of recreationists to use these natural areas with the need to maintain their ecological integrity. Environments with low productivity may be particularly susceptible due to low resistance and resilience to recreational impacts. Our study examined 28 all-terrain vehicle (ATV) trails within the Avalon Wilderness Reserve and the adjacent surrounding area on the island of Newfoundland, Canada. We found that different habitat types (boreal forest, heaths, and bogs) differ in resistance and resilience to both direct on-trail erosion and indirect off-trail vegetation impacts of ATV trails. Dry forested sites were more resistant to direct on-trail erosion but less resistant to indirect off-trail vegetation disturbance. Heath sites were less resistant to direct on-trail erosion but highly resistant to indirect off-trail disturbance. Bog sites had low resistance to both direct and indirect trail disturbance. There have been limited studies on ATV trail impacts in boreal environments, and our findings provide guidance for managers in such environments to manage recreational vehicle use.

The buckthorns Rhamnus cathartica and Frangula alnus are nonnative invasive species in North America whose seeds are primarily dispersed by birds. This paper presents the first major compilation of the bird species that eat R. cathartica and F. alnus in eastern North America, where these buckthorns are most invasive and have few common congeners. Using fecal samples, observations, and an extensive literature search, I document 46 bird species that consume R. cathartica and F. alnus, and discuss which are the most competent dispersers of the seeds. I also correct a frequently repeated belief that “blackbirds” are efficient dispersers of R. cathartica and F. alnus.

We assessed the status and richness of birds in a remote region of northwest Mexico and provided the first description of a bird community in foothills thornscrub vegetation across the full annual cycle of seasons. Our efforts were part of a broad program to describe biodiversity and conservation value of the Northern Jaguar Reserve. This large private reserve was recently proposed for federal protection, in part, because it supports the northernmost breeding population of jaguars (Panthera onca) and extensive riparian woodlands along the largest free-flowing river in western Mexico. The reserve and surrounding region are dominated by foothills thornscrub, which is a vegetation community that covers a vast transition zone between tropical forest and desert-scrub in northwest Mexico but is not represented in the federal system of Natural Protected Areas. Bird species richness was similar to that found in other protected areas in western Mexico. Over seven years, we observed 214 species of birds and estimate that 241 species are present (95% CI = 225–257). Community composition was temporally dynamic; 49% of species were winter residents or passage migrants, 31% were permanent residents, and 15% were summer residents. We observed 10 species that were breeding or wintering north of the previously described limits of their geographic ranges. We observed 13 species of conservation concern in Mexico, including the Bald Eagle (Haliaeetus leucocephalus) and Military Macaw (Ara militaris) that occur at the extreme southern and northern edges of their breeding ranges, respectively. High environmental variation and unique biogeographic and physiographic settings in this region promote high bird species richness and high conservation value.

The open canopy xeric forests of Cherrywood, Ganier, and Harris Ridges in Radnor Lake State Natural Area, Nashville, Tennessee, were sampled to determine species diversity and stems/ha of trees, saplings, and seedlings. Chestnut oak (Quercus prinus) was dominant in each forest, but tree, sapling, and seedling stems/ha means were significantly larger in Ganier than Cherrywood and Harris. Ganier has had heavy trail use but no hunting since 1973. Of the 12 tree species present on Ganier, only two species exceeded 5% of the total tree stems/ha. Harris had hunting but no hiking trail until 2013, and six of the 21 tree species exceeded 5% of the total tree stems/ha. At Harris, shagbark hickory (Carya ovata), common hackberry (Celtis occidentalis), and September elm (Ulmus serotina) had significantly more tree and seedling stems/ha than Cherrywood and Ganier. The larger populations of trees and seedlings are associated with reduced herbivory and seed consumption, which are an indirect result of hunting. For Cherrywood, five of the 19 tree species exceeded 5% of the total tree stems/ha. The intermediate position of Cherrywood, between Ganier and Harris, in relation to species diversity and the number of species that exceeded 5% of the total tree stems/ha, may be explained by no hiking and no hunting since 1973. In urban natural area ridge forests, trampling by hikers appears to be the origin of decreased species diversity and a dominant tree species population increase. Conversely, hunting is associated with greater species diversity and larger populations of subdominant species.

Rhamnus cathartica is a Eurasian shrub that has invaded woodland habitats of eastern North America. While historically known from more mesic habitats, it is often found in wetland habitats in Illinois, Minnesota, and Wisconsin, USA. This study assessed R. cathartica's growth, architecture, and biomass allocation across multiple flooding treatments representing a soil moisture gradient spanning upland (mesic soil moisture) to wetland habitats (saturated within 30 cm of the soil surface, periodic flooding, and permanently flooded conditions) for two age classes of saplings of R. cathartica. Our results on plant growth patterns under these treatments show that young R. cathartica saplings were able to tolerate saturated soil conditions, while old saplings were able to tolerate periodic flooding. Allocation of biomass to above- versus below-ground tissues showed that both young and old saplings have similar biomass allocation patterns in relation to soil moisture treatments. Collectively, our results suggest that R. cathartica exhibits tolerance to periodic flooding, and that this may partly explain its invasion of certain wetland habitats in North America.

We analyzed the food habits of the jaguar (Panthera onca) and puma (Puma concolor) in a protected area surrounded by a fragmented landscape in northeastern Mexico. We estimated relative biomass of each prey species consumed; by analysis of 43 and 22 scat samples of jaguar and puma collected during 2010–2012. The diet of both felids was comprised mainly of wild artiodactyls; the collared peccary contributed 35.2% to the biomass of jaguar diets and white-tailed deer contributed 51.9% to puma diets. Diet composition of both felids showed moderate overlap (Pianka index = 0.57; Morisita index = 0.58), but use of the primary prey differed between species (P < 0.001). The diet of both felids included almost exclusively wild species, suggesting the presence of a good prey base that allows the coexistence of jaguars and pumas. Despite its small size and surrounding fragmentation, the Biosphere Reserve Sierra del Abra-Tanchipa is still an important refuge for large felids and their prey in northeastern Mexico.

The effect of 23 years of low intensity prescribed burning on soil and litter invertebrates was studied over 18 months. Samples were collected from 40 plots distributed among annually burned, periodically burned (every 3–4 yrs), and unburned areas of an oak woodland. A total of 26,416 invertebrates representing 21 classes and orders were extracted from soil core and litter layer samples using Berlese-Tullgren funnels. Invertebrates were 25 times more abundant in litter than soil, and Acari and Collembola were the most prevalent taxa, accounting for 76% and 17%, respectively, of the total collection. Statistical analyses of the Shannon entropy index for diversity and associated values of class and order richness, evenness, and abundance indicated that burning was not associated with significant changes in the broad invertebrate community. Average Shannon entropy indices (H) ranged from 0.73 to 0.78 across burn treatments for soil samples and from 0.43 to 0.46 for litter samples. However, within Acari, diversity indices were significantly lower (P < 0.0005) in annually burned plots (H = 0.72) versus unburned controls (H = 0.85), and periodic burn plots had an intermediate H value of 0.79. Taxa evenness was similar in all treatments (J = 0.40–0.57), reflecting the widespread distribution of Acari and Collembola and rare occurrence of several orders from which 20 or fewer individuals were collected. Fall sample dates had more diverse (soil and litter) and abundant (soil) invertebrate assemblages than the spring date (P ≤ 0.001). reflecting large seasonal shifts in Acari. The average depth of the litter layer was similar, at 2.8–3.1 cm, in all three burn treatments, and was most varied in unburned plots. Collectively, the findings suggest that long term burning of the woodland for the purpose of vegetation management has not altered significantly the broadly classified invertebrate community. Possible influences of postfire recovery interval, low fire intensity, and remnant litter refugia are considered.

In many European Union countries there is little scientific work to assess the need to conserve ultramafic areas for their biodiversity attributes. Recognition of serpentine landscapes in the Habitat Directive of the European Union has been poor. Furthermore, there is little scientific literature assessing the need to conserve ultramafic areas for their biodiversity attributes in many European Union countries. This situation is critical in Spain: the largest serpentine outcrop in the Iberian Peninsula, called the Sierra Bermeja, supports a distinctive flora and fauna with numerous uncommon or rare endemic species. These species are at risk from high levels of disturbance and habitat destruction, and have unequal levels of protection. We review the biodiversity attributes of the Sierra Bermeja, and examine the need for conservation implementation from a policy perspective. This study provides the background and a framework for characterizing the biodiversity of Sierra Bermeja, highlighting 39 endemic species. Proposals for the declaration of this mountain as a national park are reinforced, and the policy and implementation shortcomings to creating a park are examined.

The January 2015 issue of Natural Areas Journal included the article, “Using Two Climate Change Vulnerability Assessment Methods to Prioritize and Manage Rare Plants: A Case Study” by Shannon M. Still, Anne L. Frances, Amanda C. Treher, and Leah Oliver (Vol. 35, no. 1, pp. 106–121). The authors would like to make the following correction to photo credits for Figure 2 (p. 115):

Original photo credits: (A) Barry C. Johnston and the US Forest Service, (B, C) Shannon Still and Nick Jensen, (D) © Rick York and California Native Plant Society.

Corrected photo credits: (A, B) Shannon Still and Nick Jensen, (C) Barry C. Johnston and the US Forest Service, (D) © Rick York and California Native Plant Society.