Herbaceous Ground Cover Research Articles

Herbicide control of swamp titi (Cyrilla racemiflora) in restoration of ephemeral wetlands

Swamp titi (Cyrilla racemiflora L.) is a vigorous native shrub or small tree found in poorly drained areas of the southeastern U.S. Coastal Plain. In the absence of fire, it creates dense thickets that prevent herbaceous groundcover in ephemeral wetlands, degrading habitat for uncommon and endangered amphibians and other genera. In our study, aquatic herbicides and methods of application were examined at two forests in north Florida for restoration of ephemeral wetland habitat to benefit wetland‐breeding amphibians. Glyphosate, imazapyr, and combinations of glyphosate and imazapyr were tested in four study protocols that included an operational standard (triclopyr), treatment method control, and untreated control where appropriate. Results of foliar protocols (targeting rootstocks less than 1.5 m tall) demonstrated that glyphosate provided better titi control than imazapyr (average of 79% vs. 12% mortality), there was no strong improvement with the addition of imazapyr to glyphosate (84% mortality), glyphosate treatments had titi mortality as high or higher than the triclopyr operational treatment (57% mortality), and that methylated seed oil surfactant improved glyphosate efficacy but might have been antagonistic for combination treatments. Glyphosate and imazapyr cut stump treatments did not provide higher efficacy than the triclopyr standard treatment (60% mortality). Cut stem treatments (targeting rootstocks greater than 1.5 m tall) provided the highest level of control averaging 97, 90, 97, and 80% mortality for glyphosate, imazapyr, combination treatments, and triclopyr standard, respectively. Only directed foliar sprays reduced total groundcover and graminoid cover, with triclopyr treatment giving the least reduction of desired herbaceous groundcover.

Territory establishment and microhabitat selection of Bachman's sparrows in a Mississippi pine forest

AbstractBachman's sparrows (Peucaea aestivalis) are an obligate southern open pine forest species linked to disturbance regimes (e.g., fire, windthrow) that reduce canopy cover and promote herbaceous groundcover needed for nesting, foraging, and concealment from predators. Early successional groundstory characteristics suitable for Bachman's sparrows are ephemeral in nature, raising questions about the perceived visual cues created by vegetation structural characteristics and how these characteristics influence multi‐scale habitat selection. We quantified habitat selection for 40 breeding and post‐breeding male Bachman's sparrows within 5 separately managed open pine management sub‐units at Sam D. Hamilton Noxubee National Wildlife Refuge in east‐central Mississippi, USA, from 2020–2021. We captured and color‐banded 20 individuals each year and used weekly resight locations and resource selection function models to assess factors influencing territory establishment (i.e., second‐order selection) within our study area, and microhabitat selection (i.e., third‐order selection) within territories. Bachman's sparrow territory establishment was positively influenced by evergreen cover and fire disturbance, and negatively influenced by tree canopy cover, and distance to unpaved roads. Within territories, sparrows selected areas with a greater basal area of pine (18 m2/ha), more available perching options (>9), and an abundance of native herbaceous groundcover (>36%). They also selected recently burned areas (1–3 yr) with low visual obstruction (<40 cm), and a low percent coverage of leaf litter (<33%). A better understanding of territory establishment and microhabitat selection of the Bachman's sparrow underscores the importance of frequent fire and is helpful in guiding conservation and management efforts for this declining species.

VEGETASI TAMAN URBAN SEBAGAI PENYEDIA PAKAN BAGI BEBERAPA TROPHIC GUILD BURUNG HERBIVORA: STUDI TAMAN LAPANGAN BANTENG, JAKARTA PUSAT

Vegetal food is the most important resource for herbivores. The study of food consumed by bird community in Indonesia, especially in urban environments is needed to provide an overview of the ability of City Parks to support bird communities. The aim was to determine the urban park vegetation in the Lapangan Banteng park as a potential food source for urban birds, especially frugivores, nectarivores and granivores. The study was conducted in September until December 2018 . Data were analyzed using Rstudio and ImageJ. The results showed that there were 7 species of birds consisting: four species of granivores (Passer montanus, Streptopelia chinensis, Lonchura punctulata, and Pycnonotus aurigaster) and three species of frugivores (Psittacula alexandri, Dicaeum trochileum, Treron vernans) which were observed to use plants as food resource Lapangan Banteng park. Birds used 30% of trees (Syzygium polyanthum, Melaleuca leucadendra, Ficus benjamina) and 70% of herbaceous ground cover (Arachis pintoi., Phoenix sp., Pennisetum purpureum, Axonopus compressus, Cynodon dactylon, Cyperus rotundus, and Eleusine indica). The availability of sufficient natural food in nature will have an impact on both bird conservation and the environment. The availability of natural food will improve bird conservation and ensure the sustainability of urban biodiversity.

Biological control of the invasive plant Tradescantia fluminensis with the fungus Kordyana brasiliensis in Australia: Host range and initial releases

The herbaceous groundcover plant Tradescantia fluminensis (wandering trad) has become a significant invader of temperate and subtropical forest ecosystems in Australia. Classical biological control (biocontrol) offers a sustainable and broad-scale management strategy to reduce wandering trad populations. The leaf-smut fungus Kordyana brasiliensis from Brazil, investigated as part of the New Zealand biocontrol program for wandering trad, was identified as a promising option for biocontrol in Australia. Additional research, however, was required to investigate further the host range of K. brasiliensis and fully assess risks since several native species in the family Commelinaceae are present in Australia. Kordyana brasiliensis only developed lesions on the 14 different accessions of wandering trad tested. Of the 28 non-target plant taxa tested, 5 developed flecks following inoculation with K. brasiliensis. In 2019, initial releases were performed in two regions, the Shoalhaven in New South Wales and Dandenong Ranges in Victoria, to obtain contrasting information on the development of the fungus post-release. Kordyana brasiliensis lesions were detected on wandering trad at the 4 plots in the Shoalhaven within a couple of months of the release. In contrast, a few lesions were detected only 5 months after the release at a few of the 9 plots in the Dandenong Ranges. Cooler temperatures in the Dandenong Ranges may have hampered development of the fungus. After 26–32 months of those initial releases, wandering trad foliage cover had declined substantially in 3 of the 4 plots in the Shoalhaven but had remained stable in the Dandenong Ranges plots. While the reduction in wandering trad cover may have resulted from recurrent disease caused by K. brasiliensis at the Shoalhaven plots, a longer post-release monitoring period is required to support this conjecture with greater certainty.

Rapid assessment of mine rehabilitation areas with airborne LiDAR and deep learning: bauxite strip mining in Queensland, Australia

Rehabilitation of disturbed sites is a complex process requiring constant monitoring and assessment, with current methods being somewhat obsolete, manual, and rather fraught with risk in terms of beneficial outcomes of the evaluation. This study challenges the status quo of manual assessments and build a new methodology to recognise a clear need for a quasi-automated and reliable remote sensing method to achieve rapid mine rehabilitation monitoring. The aim of this study was to innovate and develop an ensemble analytic methodology for the use of airborne LiDAR, in conjunction with deep learning, to rapidly evaluate the rehabilitation status of post-mined areas. Airborne LiDAR datasets, obtained via an Optech ORION m/c 200 sensor, were collected over bauxite mining operations on the western coast of Cape York Peninsula, Queensland, Australia. These datasets were processed into a 3 D point cloud using the Esri ArcGIS Pro platform. An ensemble analytical approach was developed, leading with a Convolutional Neural Network (CNN) algorithm, which was trained to recognise, then classify images of the reference site (natural ecosystems) and active rehabilitation areas. The result of this classification was then leveraged, training in turn a support vector machine (SVM) algorithm which assessed the entire LiDAR collection, resulting in a predictive surface of rehabilitation status. This surface, as the final analytical product, was assessed for validity using ground-truth plot data and an ordinary least squares regression model, as well as comparison to subject matter expert evaluation through a Delphi expert panel assessment. The results indicate that the predictive surface, as the final analytical product, had statistically significant correlation coefficient with multiple attributes (or predictor) that correlated with the rehabilitation status interpretation. These predictor variables were primarily structural in nature and included the canopy height, sub-canopy height, key species as a proportion of canopy, herbaceous ground cover percentage, litter ground cover percentage, and distance from haul road (p < 0.05). A Delphi expert collaboration comprised of ten environmental science subject matter experts and 600 observations, indicated a high precision (r = 0.89 at p < 0.05) of the prediction surface when compared with a subject expert panels assessment, as well as a high Total Deviation Index (TDI) of 16% (p < 0.05). This indicated positive agreement between the panel’s assessment and the predictive surface. This study suggests that airborne LiDAR and deep learning ensemble analytics can be used as a rapid means to estimate the rehabilitation status of disturbed sites.

Restoration Trajectories and Ecological Thresholds during Planted Urban Forest Successional Development

Successfully reconstructing functioning forest ecosystems from early-successional tree plantings is a long-term process that often lacks monitoring. Many projects lack observations of critical successional information, such as the restoration trajectory of key ecosystem attributes and ecological thresholds, which signal that management actions are needed. Here, we present results from a 65 ha urban temperate rainforest restoration project in Aotearoa New Zealand, where trees have been planted annually on public retired pasture land, forming a 14 years chronosequence. In 25 plots (100 m2 each), we measured key ecosystem attributes that typically change during forest succession: native tree basal area, canopy openness, non-native herbaceous ground cover, leaf litter cover, ground fern cover, dead trees, and native tree seedling abundance and richness. We also monitored for the appearance of physiologically-sensitive plant guilds (moss, ferns, and epiphytes) that may be considered ecological indicators of succession. Linear regression models identified relationships between all but one of the key ecosystem attributes and forest age (years since planting). Further, using breakpoint analysis, we found that ecological thresholds occurred in many ecosystem attributes during their restoration trajectories: reduced canopy openness (99.8% to 3.4%; 9.6 years threshold), non-native herbaceous ground cover (100% to 0; 10.9 years threshold), leaf litter cover (0 to 95%; 10.8 years threshold), and increased tree deaths (0 to 4; 11 years threshold). Further, juvenile native plant recruitment increased (tree seedling abundance 0 to ~150 per 4 m2), tree seedling species richness (0 to 13 per 100 m2) and epiphytes colonized (0 to 3 individuals per 100 m2). These and other physiologically-sensitive plant guilds appeared around the 11 years mark, confirming their utility as ecological indicators during monitoring. Our results indicate that measurable, ecological thresholds occur during the restoration trajectories of ecosystem attributes, and they are predictable. If detected, these thresholds can inform project timelines and, along with use of ecological indicators, inform management interventions.

Honeysuckle (Lonicera maackii) Presence is Associated with Reduced Diversity and Richness of Flowering Spring Flora in Central Kentucky

Invasive plant species can have significant, adverse effects on forest ecosystems. By outcompeting native species for resources, invasive species suppress the richness and diversity of many forest communities. This study focuses on the associations of Amur honeysuckle (Lonicera maackii Rupr.) with spring flora in Raven Run Nature Sanctuary in Lexington, Kentucky, where abundant L. maackii threatens native biodiversity. Plots were surveyed for percent herbaceous groundcover and abundance of flowering spring flora at three levels of L. maackii density (high, low, and no L. maackii). Results indicate that L. maackii abundance is associated with lower species richness, abundance, and early-season diversity of flowering native spring flora. Importantly, this study extends the existing robust literature evaluating the widespread effects of L. maackii to the Kentucky River Palisades, a sensitive and botanically important corridor in central Kentucky.

Identifying thresholds in the impacts of an invasive groundcover on native vegetation

Impacts of invasive species are often difficult to quantify, meaning that many invaders are prioritised for management without robust, contextual evidence of impact. Most impact studies for invasive plants compare heavily invaded with non-invaded sites, revealing little about abundance–impact relationships. We examined effects of increasing cover and volume of the non-native herbaceous groundcover Tradescantia fluminensis on a temperate rainforest community of southern Australia. We hypothesised that there would be critical thresholds in T. fluminensis abundance, below which the native plant community would not be significantly impacted, but above which the community’s condition would degrade markedly. We modelled the abundance–impact relationship from 83 plots that varied in T. fluminensis abundance and landscape context and found the responses of almost all native plant indicators to invasion were non-linear. Native species richness, abundance and diversity exhibited negative exponential relationships with increasing T. fluminensis volume, but negative threshold relationships with increasing T. fluminensis cover. In the latter case, all metrics were relatively stable until cover reached between 20 and 30%, after which each decreased linearly, with a 50% decline occurring at 75–80% invader cover. Few growth forms (notably shrubs and climbers) exhibited such thresholds, with most exhibiting negative exponential relationships. Tradescantia fluminensis biomass increased dramatically at > 80% cover, with few native species able to persist at such high levels of invasion. Landscape context had almost no influence on native communities, or the abundance–impact relationships between T. fluminensis and the plant community metrics. Our results suggest that the diversity of native rainforest community can be maintained where T. fluminensis is present at moderate-to-low cover levels.

Seed Consumption by Gopher Tortoises (Gopherus polyphemus) in the Globally Imperiled Pine Rockland Ecosystem of Southern Florida, USA

Turtles have been identified as key dispersers of seeds in many ecosystems; however, seed dispersal by turtles (chelonochory) has received far less attention than seed dispersal by birds or mammals. We assessed the role of gopher tortoises (Gopherus polyphemus)—a keystone species—as potential seed dispersers by analyzing the seed composition of their diet in a globally imperiled ecosystem: the pine rockland ecosystem of South Florida. The pine rocklands contain high numbers of both endemic and invasive plant species that may be dispersed by tortoises. We collected scat samples from wild gopher tortoises living in the pine rockland habitats in the Richmond Tract (Miami-Dade County, Florida, USA) and examined the samples to identify seeds consumed. We extracted 2484 seeds from 53 samples from at least 10 individual tortoises. Of the 2484 individual seeds, we distinguished 33 morphospecies and identified 23 to the species taxonomic level. The 14 most abundant seed species in the scat constituted > 90% of all seeds eaten by the tortoises. Three of the 14 most abundant seeds were from nonnative plants, but none were among the most disruptive invasive species. Tortoises consumed mostly herbaceous ground cover and fibrous grasses. Given that the tortoises were consuming several ground cover plants and contained a high density of those seeds in their scats, they seemed to be consuming the seeds as bycatch rather than selectively feeding on them, therefore supporting Janzen's “foliage is the fruit” hypothesis. The prevalence of many seeds and a variety of seed species in the tortoise scat suggests that gopher tortoises may be serving the ecological role of a seed dispersal agent for some of the plants they consume within the pine rocklands.

Efficacy of Postemergence Herbicides for Control of Small-Leaf Spiderwort (Tradescantia fluminensis) in Florida

Tradescantia fluminensis (small-leaf spiderwort; SLSW) is a fast-growing herbaceous groundcover and one of the most problematic invasive plants in Florida. The objective of this research was to determine the efficacy of selected postemergence herbicides for SLSW control in greenhouse and field experiments in Florida. An additional objective was to determine if pre-cutting plants would increase herbicidal efficacy. In greenhouse experiments, cutting mature SLSW plants increased the control of most herbicides evaluated. Overall, triclopyr ester provided the highest level of control along with triclopyr amine, triclopyr choline, and glufosinate, all of which were similar. Few differences were observed between 2,4-D, aminopyralid, metsulfuron-methyl, sulfentrazone, and glyphosate and all provided ≤66% control as evidenced by shoot weight reduction. In field experiments, pre-cutting SLSW had no effect on herbicide efficacy. Triclopyr was again generally the most efficacious treatment, outperforming glyphosate, aminopyralid, glufosinate, and fluroxypyr on most evaluation dates, especially as trials progressed past 5 mo. Overall, data suggest that triclopyr would be the most effective option for SLSW management. However, as efficacy was noted with fluroxypyr, glyphosate, and glufosinate depending upon location, other options exist. Further research is needed to determine reapplication intervals and effects on nontarget native plants in order to develop comprehensive management plans.

Seeds and seedlings of oaks suffer from mammals and molluscs close to phylogenetically isolated, old adults.

Mammals and molluscs (MaM) are abundant herbivores of tree seeds and seedlings, but how the trees and their environment affect MaM herbivory has been little studied. MaM tend to move much larger distances during the feeding stage than the more frequently studied insect herbivores. We hypothesize that MaM (1) select and stay within the patches that promise to be relatively the richest in seeds and seedlings, i.e. patches around adult trees that are old and within a distantly related, less productive neighborhood; and (2) try to remain sheltered from predators while foraging, i.e. mammals remain close to adult trees or to cover by herbs while foraging, and might force their mollusc prey to show the opposite distribution. We exposed oak acorns and seedlings in a temperate forest along transects from adult conspecifics in different neighbourhoods. We followed acorn removal and leaf herbivory. We used exclusion experiments to separate acorn removal by ungulates vs. rodents and leaf herbivory by insects vs. molluscs. We measured the size of the closest conspecific adult tree, its phylogenetic isolation from the neighbourhood and the herbaceous ground cover. Consistent with our hypothesis, rodents removed seeds around adult trees surrounded by phylogenetically distant trees and by a dense herb cover. Molluscs grazed seedlings surrounding large conspecific adults and where herb cover is scarce. Contrary to our hypothesis, the impact of MaM did not change from 1 to 5 m distance from adult trees. We suggest that foraging decisions of MaM repulse seedlings from old adults, and mediate the negative effects of herbaceous vegetation on tree recruitment. Also, an increase in mammalian seed predation might prevent trees from establishing in the niches of phylogenetically distantly related species, contrary to what is known from insect enemies.

Abundance of montane salamanders over an elevational gradient.

Climate change is expected to systematically alter the distribution and population dynamics of species around the world. The effects are expected to be particularly strong at high latitudes and elevations, and for ectothermic species with small ranges and limited movement potential, such as salamanders in the southern Appalachian Mountains. In this study, we sought to establish baseline abundance estimates for plethodontid salamanders (family: Plethodontidae) over an elevational gradient in Great Smoky Mountains National Park. In addition to generating these baseline data for multiple species, we describe methods for surveying salamanders that allow for meaningful comparisons over time by separating observation and ecological processes generating the data. We found that Plethodon jordani had a mid‐elevation peak (1,500 m) in abundance and Desmognathus wrighti increased in abundance with elevation up to the highest areas of the park (2025 m), whereas Eurycea wilderae increased in abundance up to 1,600 m and then plateaued with increasing uncertainty. Litter depth, herbaceous ground cover, and proximity to stream were also important predictors of abundance (dependent upon species), whereas daily temperature, precipitation, ground cover, and humidity influenced detection rates. Our data provide some of the first minimally biased information for future studies to assess changes in the abundance and distribution of salamanders in this region. Understanding abundance patterns along with detailed baseline distributions will be critical for comparisons with future surveys to understand the population and community‐level effects of climate change on montane salamanders.

T0 Early Permian coal-forest preserved in situ in volcanic ash bed in the Wuda Coalfield, Inner Mongolia, China

An early Permian tuff bed between Coal 7 and Coal 6 of the Wuda Coalfield in Inner Mongolia bears T0 peat-forming vegetation preserved in situ. Documentation of the fossil record uncovered in an area of about 80 m2 shows 14 morphotaxa representing 11 whole-plant species with a wide variety of growth forms. The uncovered phytocoenosis is interpreted as a forest dominated by cordaites as the tallest trees, the remains of which covered over 50% of the excavated area. Marattialean tree ferns represent the lower canopy that was not taller than about 3 m. This storey fills gaps between cordaites and covers over 20% of the area. A rare element of lower canopy taxa was the cycadophyte genus Pterophyllum represented by a single plant. Poorly developed herbaceous groundcover includes Sphenophyllum oblongifolium, and four small fern species mostly with sphenopteroid type of foliage. Although members of the herbaceous layer covered only 7% of the excavated area, it was the most diverse storey of the peat-forming forest. Considering the small area excavated, along with the higher diversity known from the same tuff bed in the adjacent, former opencast mine, it appears that species richness in the forest was comparable to some of the less diverse Westphalian peat-forming floras in Euramerica.

Litter to glitter: promoting herbaceous groundcover and diversity in mid-southern USA oak forests using canopy disturbance and fire

BackgroundIn oak-dominated communities throughout eastern North America, fire exclusion and subsequent woody encroachment has replaced the “glitter” of once robust and diverse wildflower and grass layers with leaf-litter dominance. Restoring the important herbaceous components of Eastern oak ecosystems could involve pairing heavy canopy disturbance with growing-season fire, but potential negative effects warrant research. Beginning with 20 ha replicates of closed-canopy forest at three sites across Tennessee and North Carolina, USA, we monitored groundcover response to combinations of thinning (none; light: 14 m2 ha−1 residual basal area; and heavy: 7 m2 ha−1) and seasonal fire (none; March: pre leaf expansion; and October: pre leaf abscission) from 2008 to 2016.ResultsBefore treatments, woody plants and leaf-litter-dominated groundcover and herbaceous plants were rare (<6% groundcover, 118 species). By 2016, herbaceous groundcover averaged 59% after heavy thinning and three biennial burns, and 359 herbaceous species were documented. Only 6% (23) of these species appeared negatively affected by applied disturbances. Across sites, thin-and-burn treatments increased graminoid groundcover 14-fold, forb groundcover 50-fold, herbaceous richness 9-fold, and herbaceous diversity 10-fold, relative to unmanaged stands. These increases were often greater where fire was repeatedly applied, and only after repeated fire was herbaceous response greater in heavily thinned stands relative to lightly thinned stands. Burn-only treatments rarely affected herbaceous metrics, and thin-and-burn treatments more than doubled woody groundcover. This suggests that canopy reduction, leaf-litter consumption, and pulses of bare ground were more related to positive herbaceous responses than to the control of woody competition in the understory. Fire season effects were not observed, but herbaceous response after less intense October fires was comparable to that following more intense March fires.ConclusionsOur results conflict with warnings concerning the potential negative effects of disturbance on herbaceous diversity east of the prairie–woodland transition zone. Canopy disturbance and repeated fire, regardless of season, widely restored herbaceous groundcover and diversity in Eastern oak ecosystems. Herbaceous components were resilient to extended periods of fire exclusion, but current conservation programs often prioritize existing, high-quality sites. Our results suggest that such policies may overlook the tremendous restoration potential present in otherwise inconspicuous understories of closed-canopy oak forests throughout eastern North America.

Growth control of herbaceous ground cover and egg quality from an integrated poultry-hazelnut orchard system

The present study was designed to assess the impact of hen grazing on plant biodiversity in the ground cover of hazelnut orchards, as well as the quality of eggs from hens grazing in the orchards. Two different sites of hazelnut orchards located in Basilicata region were selected to conduct this study. The results showed that hen grazing affected the composition of herbaceous stratum of the orchards. By using the quadrat method, a total of 99 (46 in site A and 53 in site B) plant species were identified at the beginning of the trial. After hen grazing, the number of identified plants dropped to 72 (30 in site A and 42 in site B). Amongst the most consumed species we found Lolium sp., Trifolium sp., Polygonum sp., Cichorium intybus, Cynodon dactylon. Alpha diversity analysis (species richness, diversity and evenness) as well as beta diversity analysis (Morisita-Horn and Sørensen indices) confirmed that hen grazing played a role in controlling vegetation growth. Concerning egg quality, most of the chemical parameters differed significantly when comparing the eggs from the sites with those from the control group, indicating that egg quality was influenced by the food resources available in each site. Overall, our results confirm that poultry may play a positive role in an orchard system. Highlights - The impact of an integrated poultry-hazelnut orchard system on herbaceous plant species diversity and on egg quality was evaluated. - Hen grazing may benefit herbaceous ground cover biodiversity of the orchards. - Egg quality may be affected by the food resources available in the orchards.

Dry conifer forest restoration benefits Colorado Front Range avian communities.

Fire suppression has increased stand density and risk of severe, stand-replacing wildfire in lower elevation dry conifer forests of western North America, threatening ecological function. The U.S. Forest Service's Collaborative Forest Landscape Restoration Program (CFLRP) aims to mitigate impacts to ecological function, while mandating effectiveness monitoring to verify restoration success. Expected benefits include improved conditions for biodiversity, but relatively few empirical studies evaluate restoration effects on biodiversity. We applied the Integrated Monitoring in Bird Conservation Regions program to survey birds in relation to CFLRP treatments along the Colorado Front Range in 2015-2017. We employed hierarchical models to analyze species occupancy and richness at 1972 points nested within 141 1-km2 grid cells. Our objectives were to investigate (1) species occupancy relationships with treatments at local (point) and landscape (grid) spatial scales, (2) potential mechanisms for treatment relationships considering species and treatment relationships with forest structure and composition (i.e., habitat relationships), and (3) treatment and habitat relationships with species richness. The data supported positive and negative point-level treatment relationships, suggesting uneven species distributions between treated and untreated points. At the grid scale, however, we only found positive species relationships with percent area treated, and accordingly, grid-level species richness increased with treatment extent. Potential mechanisms for treatment relationships included treatments generating foraging opportunities for aerial insectivores by opening the canopy, improving conditions for ground-associated species by increasing herbaceous growth, and limiting opportunities for shrub-nesting species by reducing shrub cover. Landscape-scale patterns suggest CFLRP treatments can benefit avian communities by generating habitat for open-forest species without necessarily eliminating habitat for closed-forest species. Our results provide evidence for a commonly expected but rarely verified pattern of increased species richness with forest heterogeneity. We suggest restoration treatments will most benefit forest bird diversity by reducing canopy cover, encouraging herbaceous ground cover, limiting ladder fuel species, and encouraging shrub diversity in canopy openings, while maintaining some dense forest stands on the landscape.

Direct and indirect effects of pine silviculture on the larval occupancy and breeding of declining amphibian species

Abstract Plantation silviculture is increasing globally and is particularly intensive in temperate coniferous forests, where densely planting trees requires practices common to non‐conifer systems that can alter forest floor microhabitat, and potentially threaten amphibian persistence. Most declining amphibian species depend on specific forest microhabitats as terrestrial refugia, but amphibian extirpation associated with tree harvest alone appears unlikely, suggesting that impacts of planting forests on groundcover might better predict recent declines in amphibian occupancy. We repeatedly sampled larval presence or absence of 10 amphibian species native to temperate coniferous forest in the Southeastern United States for one year at 62 isolated wetlands, located in either naturally regenerating or planted forest (plantation). We assessed three direct ways that planted forests might reduce amphibian breeding site occupancy by: (a) increasing conifer densities, (b) decreasing groundcover, and (c) an indirect pathway, whereby increased tree densities at plantations might reduce groundcover and thus amphibian site occupancy. After controlling for wetland traits and accounting for differences in detection, breeding site occupancy for 8/10 amphibian species was dependent upon whether forests were planted surrounding wetlands (within 300 m). Herbaceous groundcover, not canopy, most commonly influenced occupancy and increased occupancy for declining surface active or fossorial amphibians. Path analyses showed that, by directly and indirectly reducing groundcover (via conifer densities), plantations had significantly lower occupancy of two declining surface active or fossorial frog species, whereas two common aquatic frog species were tolerant to planting conifers. Among declining species, salamanders showed a greater reduction in occupancy than anurans, likely because of greater vulnerability to the drier forest floor conditions of plantation than naturally regenerating forests. Synthesis and applications. Direct negative impacts of coniferous plantation on amphibians can be addressed by limiting groundcover and soil impacts, including switching from high intensity practices, such as mechanical chopping vegetation or bedding soil, to lower intensity site preparation treatments that are less likely to significantly disturb groundcover. Indirect negative effects of dense canopy cover at planted forests could be lowered by periodically thinning canopies prior to final harvest, thus increasing intact forest groundcover and the conservation of both common and declining amphibians.

Effects of forestry-driven changes to groundcover and soil moisture on amphibian desiccation, dispersal, and survival.

Over 80% of amphibian species that are declining are forest dependent. Forestry practices are a major cause of forest alterations globally, and it is well documented that clearcutting can contribute to amphibian declines. However, there might be adverse effects of forestry practices other than clearcutting. For example, planting overstory trees in rows (plantations) can change groundcover microhabitats and soil moisture levels, but the effects of this common practice on amphibian populations are not well studied. We compared the impacts of common intensive pine plantation operations to naturally regenerated pine forests on the desiccation, movement rates, behavior, and survival of >900 juvenile southern toads (Anaxyrus terrestris). Pine plantations had significantly more accumulation of conifer needles and less exposed soil, herbaceous groundcover, broadleaf litter, and soil moisture than natural pine forests despite the greater canopy cover at plantations. Litter cover explained 85% of groundcover microhabitat variance among forest types and predicted minimum soil moisture levels. When toads were held in small outdoor enclosures that constrained microhabitat selection, 24-h desiccation rates and 72-h mortality were significantly greater in pine plantation than in naturally regenerated pine forest because of lower soil moisture, especially during low rainfall periods. In large outdoor pens where juvenile amphibians could select microhabitats, movement was strongly directed down slope and increased with precipitation. However, initial speeds were positively associated with pine density, likely because toads were trying to evacuate from the drier high-pine-density areas. High-intensity silviculture practices that eliminate herbaceous or vegetative groundcover, such as roller chopping and scalping, increase amphibian desiccation because planted conifers dry the upper soil layer. Our study highlights the importance of prioritizing lower intensity silviculture practices or lower pine densities to retain groundcover microhabitat that serves as amphibian refugia from dry conditions that are predicted to increase in frequency with climate change.

Wildlife habitat condition in open pine woodlands: Field data to refine management targets

Open pine ecosystems of the southern United States are a conservation priority for many agencies, organizations, and private landowners. These woodlands, characterized by moderately-stocked overstories, low cover of midstory, and grass-dominated herbaceous groundcover, provide important habitat for a suite of rare and declining wildlife species. To provide guidance for land managers engaged in habitat restoration in open pine ecosystems, ranges of desired conditions for elements of vegetation structure have been developed using literature survey and expert opinion. We compared empirical data on habitat occupancy for 17 wildlife species from second-growth longleaf pine woodlands in southwestern Georgia with recommended ranges for basal area (BA) of all pine, BA of pine ≥ 35.5 cm dbh, percent canopy cover, percent herbaceous cover, and percent shrub cover. Vegetation data were taken from 864 monitoring plots and Mahalanobis distance models were used to develop habitat suitability indices from the wildlife data. Recommendations for shrub cover and BA of pines ≥ 35.5 cm fit well with model predictions for all wildlife species. However, mean BA of all pines at sites used by wildlife were at the low end of the recommended range. Herbaceous cover at sites used by wildlife was well below the recommended range, whereas canopy cover was well above recommendations, suggesting these ranges should be expanded. These modifications could provide managers of open pine ecosystems greater flexibility, allowing them to incorporate a broader suite of objectives in their management while still providing habitat for wildlife species of concern. Moreover, our models suggest that monitoring presence of open pine indicator bird species may be an efficient method to assess restoration or management progress of open canopy pine systems.

UAS-GEOBIA Approach to Sapling Identification in Jack Pine Barrens after Fire

Jack pine (pinus banksiana) forests are unique ecosystems controlled by wildfire. Understanding the traits of revegetation after wildfire is important for sustainable forest management, as these forests not only provide economic resources, but also are home to specialized species, like the Kirtland Warbler (Setophaga kirtlandii). Individual tree detection of jack pine saplings after fire events can provide information about an environment’s recovery. Traditional satellite and manned aerial sensors lack the flexibility and spatial resolution required for identifying saplings in early post-fire analysis. Here we evaluated the use of unmanned aerial systems and geographic object-based image analysis for jack pine sapling identification in a region burned during the 2012 Duck Lake Fire in the Upper Peninsula of Michigan. Results of this study indicate that sapling identification accuracies can top 90%, and that accuracy improves with the inclusion of red and near infrared spectral bands. Results also indicated that late season imagery performed best when discriminating between young (&lt;5 years) jack pines and herbaceous ground cover in these environments.