We surveyed high quality, remnant black oak sand savannas across four sites in northeastern Illinois to compare characteristics of stand structure and tree vigor with fire history. Dendrochronological methods were applied to 289 dated fire scars identified on 60 Quercus velutina trees. Stand structure was characterized using 30 circular plots (0.04 ha each) per stand during summer 2007. Tree recruitment dynamics differed among the four stands, suggesting that canopy decline dynamics among them is likely to differ in coming decades. Frequent fire intervals (less than two years) were associated with canopy openness, but also a paucity of future canopy trees. Under these frequent fire regimes, we predict a loss of canopy cover, as no smaller trees were present to assume dominance. Fire intervals longer than two years were associated with transition to closed canopy forests. These results suggest that savanna managers should consider other disturbances, such as selective cutting and or grazing, along with fire to sustain both herbaceous and canopy tree components.

Non-native earthworm invasions in north-temperate North America cause substantial adverse effects to hardwood forest ecosystems. Quantification of invasions is necessary for understanding impacts and identifying remnant earthworm-free areas, but existing sampling techniques are effort-intensive and/or environmentally damaging. We: (1) developed and applied a protocol that allows rapid classification of earthworm invasion into five stages based primarily on visual assessment of the forest floor, (2) sampled earthworms to test whether the protocol's stages can predict invasion by different species, and (3) assessed relationships between individual forest floor characteristics and presence of different earthworm species. Based on differences in biomass among points assigned to different stages, the 5-stage classification protocol accurately identified the onset of invasion by Lumbricus rubellus and Lumbricus terrestris, the species of greatest management concern in the northern Midwest. Except for middens as a predictor of L. terrestris presence, no forest floor variable was useful by itself for assessing invasions. The 5-stage protocol provides an efficient approach for assessing earthworm invasions in hardwood forests of the U.S. northern Midwest, can be implemented with minimal training, and serves as a blueprint for similar protocols in other regions experiencing earthworm invasions.

The goal of this study was to evaluate the efficacy of four herbicides for controlling invasive Kentucky bluegrass (Poa pratensis L.) and tall fescue (Festuca arundinacea Schreb.) in idle grasslands by monitoring post-treatment plant communities. Experiments were conducted in two remnant savannas in central Kentucky. With the exception of domestic grazing, these sites were chosen because they were undisturbed by agriculture and development. Single treatments of 0.2 kg ai/ha imazapic, 0.2 kg ai/ha clethodim, 0.2 kg ai/ha imazapic 1.1 kg ai/ha glyphosate, 0.03 kg ai/ha sulfosulfuron, and an untreated control were implemented in fall 2004 and spring and summer 2005 at each site in a randomized complete block design. Plant communities were monitored 3, 10, 12, 14, and 15 months after the final treatments were implemented. At 15 months post-treatment, tall fescue cover was reduced in all treatment plots relative to the untreated control, with the greatest reduction in tall fescue cover occurring in the summer treatment plots. Spring applications of each herbicide were more effective for Kentucky bluegrass control than summer or fall treatments. All herbicide treatments reduced Kentucky bluegrass compared to untreated plots. The most effective herbicide treatment was imazapic glyphosate, which reduced Kentucky bluegrass cover to less than 7%. However, the resulting bare ground facilitated invasions by other aggressive exotic species, notably musk thistle (Carduus nutans L.). Spring applications of clethodim reduced Kentucky bluegrass cover relative to the untreated plots, and resulted in the highest number of native plant species compared to all other plots. This conservation of forb cover provided by clethodim may be of importance in managing areas impaired by this aggressive, invasive grass.

Nomenclature: Carduus nutans L., Clethodim, glyphosate, imazapic, Kentucky bluegrass, musk thistle, Poa pratensis L., sulfosulfuron, tall fescue

Due in large part to fire exclusion, many oak-dominated (Quercus spp.) forests, woodlands, and savannas throughout eastern North America are being replaced by less diverse forest ecosystems. In the interior coastal plain of the southern United States, these forests are dominated in the mid- and understory by mesophytic species such as Acer rubrum L. and Liquidambar styraciflua L., which may eventually displace overstory oaks. Oak regeneration has been shown to respond positively to open canopies and prescribed burning. In 2008, a severe tornado damaged previously established study plots in a xeric oak and pine (Pinus spp.) forest in northern Mississippi. Some damaged and undamaged plots were treated with prescribed fire in 2010. Additional plots were established in damaged areas, and these plots were salvage-logged. Species composition and growth of saplings were measured to assess the impact of tornado damage and the treatments on oak regeneration. Tornado damage increased overall sapling densities, especially oaks, resulting in increased representation by upland oak species. In burned plots, oak saplings resisted damage and recovered from prescribed fire better than mesophytic saplings. Sapling densities, especially those of oaks, were lower in salvage-logged areas than in damaged areas that were not logged, resulting in greater dominance by saplings of mesophytic species. Results suggest that, on poor soils, oak regeneration requires damaged or thinned canopies and benefits from prescribed burning two years after canopy disturbance. In contrast, natural regeneration of oaks may be incompatible with salvage-logging, especially in areas that receive severe damage from wind.

The ecological significance of cultural parks and protected areas, such as battlefields, has frequently been overlooked. Yet small cultural parks with rare populations can provide refugia and colonists for re-establishment elsewhere, and thus are likely to become increasingly important as climate change leads to range shifts and accelerated population declines. We estimated the abundance of the regional endemic plant Lemhi penstemon (Penstemon lemhiensis) in Big Hole National Battlefield in western Montana. We estimated during 2009 and 2010 that approximately 1500 adult plants occurred in two subpopulations clustered on steep south-facing slopes where down-slope soil movement is highest. Results from 2011 provided evidence for an increase to approximately 3000 adult plants. The battlefield contains the largest reported population of this geographically restricted species and is, therefore, a globally-significant reserve for Lemhi penstemon. However, inflorescence rates were lower and the mean number of basal rosettes per plant, a proxy for plant age, was greater than reported elsewhere. Lemhi penstemon requires open soil microsites for regeneration and appears vulnerable to land- use change, particularly when it involves disruption of fire regimes. Spotted knapweed (Centaurea stoebe) abundance is also increasing in the study area, presenting another threat. Managing Big Hole Battlefield to simultaneously reflect a fixed historic period and support Lemhi penstemon will be a persistent challenge that will require a more active, adaptive management strategy. Our study has helped to integrate cultural and natural resource management in the Battlefield and provides a model for conservation in other cultural parks.

Appropriate response to recent, widespread bark beetle (Dendroctonus spp.) outbreaks in the western United States has been the subject of much debate in scientific and policy circles. Among the proposed responses have been landscape-level mechanical treatments to prevent the further spread of outbreaks and to reduce the fire risk that is believed to be associated with insect-killed trees. We review the literature on the efficacy of silvicutural practices to control outbreaks and on fire risk following bark beetle outbreaks in several forest types. While research is ongoing and important questions remain unresolved, to date most available evidence indicates that bark beetle outbreaks do not substantially increase the risk of active crown fire in lodgepole pine (Pinus contorta) and spruce (Picea engelmannii)-fir (Abies spp.) forests under most conditions. Instead, active crown fires in these forest types are primarily contingent on dry conditions rather than variations in stand structure, such as those brought about by outbreaks. Preemptive thinning may reduce susceptibility to small outbreaks but is unlikely to reduce susceptibility to large, landscape-scale epidemics. Once beetle populations reach widespread epidemic levels, silvicultural strategies aimed at stopping them are not likely to reduce forest susceptibility to outbreaks. Furthermore, such silvicultural treatments could have substantial, unintended short— and long-term ecological costs associated with road access and an overall degradation of natural areas.

Isle Royale National Park (IRNP) is an archipelago in west central Lake Superior. In 2010, the National Park Service Great Lakes Inventory and Monitoring Network initiated a long-term monitoring program at IRNP with the goals being to: (1) determine the current forest structure, (2) assess how succession and climate change will impact species assemblages, and (3) develop realistic management targets related to climate change impacts on IRNP forests. Five forest types were identified, with three of these (sugar maple (Acer saccharum Marsh.)/birch, eastern white cedar (Thuja occidentalis L), and balsam fir (Abies balsamea (L.) Mill.)) being climax types with little likelihood of succeeding into any other type over the next two to three decades. Two forest types (white spruce (Picea glauca (Moench) Voss),/trembling aspen (Populus tremuloides Michx.), and paper birch (Betula papyrifera Marsh.)) were in a state of transition. The long-term (> 50 year) successional pathways of all five forest types will be influenced by climate change, species' migration abilities, and disease. Many dominant species currently on the island, including balsam fir, black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.), and white spruce, are expected to become extirpated, while the abundance of other common species, including paper birch and trembling aspen, is expected to decline. The 21 km distance between the mainland and the islands will prohibit timely immigration of new species onto the island in the face of climate change. Immigration will likely be led by avian-dispersed species (Prunus spp., exotic Lonicera spp., and Rhamnus cathartica, another exotic species) with dispersal of other taxa relying on stochastic events or human transport. Managers should consider assisted migration to ensure that species assemblages remain congruent; otherwise, stable ecosystems dominated by a few non-native taxa may result. This is especially relevant on the eastern side of the island where balsam fir forests dominate in shallow, bedrock-derived soils.

White-tailed deer (Odocoileus virginianus Zimmerman) are known to disperse seeds of a hybrid complex of invasive honeysuckle shrubs in northeastern United States. We investigated whether they also disperse seeds of Amur honeysuckle, Lonicera maackii, a problematic invasive shrub in the Midwestern and eastern U.S. We found that deer ingest ripe fruit and void intact seeds of L. maackii. Based on tetrazolium tests, most (68%) of these voided seeds are viable, but the proportion viable was significantly lower than that for seeds taken directly from ripe fruits. White-tailed deer are potentially important in the long-distance dispersal of this invasive shrub.

Native prairie sites within the Northern Great Plains are being invaded by cool season invasive grasses despite utilizing even the most conservation-oriented management. Native prairie sites of the Knife River Indian Villages National Historic Site, located near the confluence of the Knife and Missouri Rivers in central North Dakota, were reassessed 23 years after the first assessment. The native prairie sites were initially assessed the summer of 1984 utilizing a modified Daubenmire technique which entailed randomly placing twenty-five ¼ m2 quadrats along transects at each native prairie site. Prior to 1976, native prairie sites were grazed by livestock; and after the National Park Service took ownership, sites were not grazed by livestock and were essentially left idle. The same technique was repeated during the summer of 2007 on the same native prairie sites surveyed in 1984, and comparisons were made between species composition of those sites in 1984 and 2007. Species composition of several sites across the landscape changed from containing a high percentage of native graminoids and forbs to containing a high percentage of invasive species such as smooth brome (Bromus inermis Leyss.) and Kentucky bluegrass (Poa pratensis L.). A few of the more xeric native prairie sites maintained a high percentage of native graminoids and forbs with minor changes in coverage. This study illustrates the emergence of invasive species and species composition changes under historic land use and climatic conditions and the roles that disturbances, such as grazing processes and fire, may play in maintaining native plant communities.

Many attempts to restore grasslands after pipeline construction, including soil manipulation such as topsoil stripping and replacement, and revegetation methods such as seeding native species or non-native cover species, have been unsuccessful. Recent pipeline techniques have used minimum disturbance and revegetation via natural recovery. The goal of this research was to evaluate natural recovery in rough fescue (Festuca hallii (Vasey) Piper) grassland in central Alberta, Canada. Plant species cover was evaluated, comparing pipeline right-of-way disturbances to undisturbed controls. Pipeline construction methods were assessed to determine which would be most successful in returning native grassland species. Pipelines with the most intense disturbances were dominated by wheatgrasses, with abundant bare ground and sparse moss and lichen cover; whereas those with the least intense disturbances had cover similar to native grassland. Results confirmed the importance of minimum disturbance in grasslands. Retaining grassland sod through plow-in pipeline construction and keeping disturbance as narrow as possible is critical to successful recovery. Rough fescue appears to recover better with plow-in pipeline construction than with seeding, most likely from intact sod. Therefore, narrow trenching with plow-in techniques is recommended for grasslands.

This five-year study (2007–2011) investigated year-to-year variation in the oak (Quercus spp.) and hickory (Carya spp.) mast production in five different variations of mixed-oak-hickory forests at the Mashomack Preserve on Shelter Island, Long Island, New York. All seven species (six oaks and one hickory) had one to three mast years during the five year study, with black oak (Quercus velutina) having the highest number of mast years and producing the largest number of acorns. Pignut hickory (Carya glabra) had a similarly high overstory importance value to black oak in the study stands but had only one mast year and produced less than half of the nuts produced by black oak. White oak (Quercus alba) was the third ranking tree species in term of overstory importance and mast production, having two mast years during the study. There was a large amount of year-to-year and stand variation in mast production. The highest amount of mast was produced in 2009 and 2010, yet there was a 3–4 fold difference between the least and most productive stands in each year. The year 2011 was unique for having very low mast production and no mast year for any of the six tree species. This is attributed to a significant drought in 2010 that persisted through the summer of 2011. The 2010 drought did not reduce mast production in that year.

This Steward's Circle Note presents information we consider important in restoring and managing bunched arrowhead (Sagittaria fasciculata), a federally listed endangered plant species. We include observations on light and water depth, past relocation efforts, and suggestions on the need to develop genetic profiles for the plant before additional relocation efforts are undertaken.