Shrub Canopy Cover Research Articles

A multiscale analysis of factors influencing Setophaga striata (Blackpoll Warbler) occupancy and abundance during the nonbreeding season in eastern Colombia

ABSTRACT Setophaga striata (Blackpoll Warbler), one of the few boreal-breeding migratory birds that migrates to the Orinoco and Amazon regions, is experiencing steep population declines. However, knowledge of the species’ distribution and habitat use during the nonbreeding season is limited. Here, we explore how stationary nonbreeding season (December to April) occupancy probabilities vary across regional and landscape scales, and with vegetation structure for S. striata in eastern Colombia. By running single-species, single-season hierarchical occupancy models and N-mixture models, we evaluated how regional (annual precipitation, nonbreeding season precipitation, driest month, elevation, and net primary productivity), landscape (habitat type and % forest in the landscape), and vegetation structure variables influenced occupancy by S. striata. In the regional analysis, occupancy was positively influenced by stationary nonbreeding precipitation and net primary productivity, and was predicted to peak at elevations between 500 and 1,000 m. At the landscape scale, occupancy and abundance were higher in agroforestry systems (in order of magnitude: shade-grown cacao, citrus plantations and silvopastures) than in forested habitats. In relation to vegetation structure, occupancy was negatively correlated with a principal component containing shrub density, canopy height, and canopy cover. Within the Orinoco region, a spatial prediction based on our results supported high occupancy rates in moister areas along and close to the Andean foothills and where the Orinoco grasslands transition into Amazonian forests. Our results highlight the importance of landscapes containing agroforestry systems as stationary nonbreeding habitats for S. striata in Colombia’s Orinoco region and the importance of promoting agroforestry systems, like shade-grown cacao, in areas with higher nonbreeding season precipitation and net primary productivity values in order to increase habitat availability for the species.

Thinning relationships of woody encroachers in a US southwestern shrubland

Woody plant encroachment degrades the economic and environmental potential of drylands by altering processes such as nutrient fluxes, ecohydrology, and ecosystem services. Though past research has investigated the encroachment process, relatively little is known about post-encroachment shrub community ecology. To better quantify dynamics within post-woody encroachment shrub communities, we combined USGS lidar height data and multispectral imagery to estimate shrub density, shrub height, shrub cover, and shrub volume across the Jornada Basin Long Term Ecological Research (JRN-LTER) site in southern New Mexico, USA. Structural estimates were analyzed in search of telltale signs of community competition, specifically, the presence of thinning relationships. Results demonstrated density-dependent thinning relationships in shrub communities of creosote and mesquite, indicating a large role for competition in arid shrub communities even at relatively low shrub densities and cover (∼35% cover). In addition, shrub volume estimates better modeled the expected thinning dynamics of shrub communities than shrub canopy cover measurements. Overall, our results indicate the utility of lidar data in extending two-dimensional descriptions of woody vegetation structure (i.e., woody canopy cover) into the critical third dimension (i.e., woody plant volume), as well as the relative importance of competition and demographic bottlenecks to vegetation structure in drylands.

Carboxylation capacity is the main limitation of carbon assimilation in High Arctic shrubs.

Increases in shrub height, biomass and canopy cover are key whole-plant features of warming-induced vegetation change in tundra. We investigated leaf functional traits underlying photosynthetic capacity of Arctic shrub species, particularly its main limiting processes such as mesophyll conductance. In this nutrient-limited ecosystem, we expect leaf nitrogen concentration to be the main limiting factor for photosynthesis. We measured the net photosynthetic rate at saturated light (Asat) in three Salix species throughout a glacial valley in High-Arctic tundra and used a causal approach to test relationships between leaf stomatal and mesophyll conductances (gsc, gm), carboxylation capacity (Vcmax), nitrogen and phosphorus concentration (Narea, Parea) and leaf mass ratio (LMA). Arctic Salix species showed no difference in Asat compared to a global data set, while being characterized by higher Narea, Parea and LMA. Vcmax, gsc and gm independently increased Asat, with Vcmax as its main limitation. We highlighted a nitrogen-influenced pathway for increasing photosynthesis in the two prostrate mesic habitat species. In contrast, the erect wetland habitat Salix richardsonii mainly increased Asat with increasing gsc. Overall, our study revealed high photosynthetic capacities of Arctic Salix species but contrasting regulatory pathways that may influence shrub ability to respond to environmental changes in High Arctic tundra.

Effects of different land-use planning instruments on urban shrub and tree canopy cover in Zurich, Switzerland

Sustainable urban development requires not only dense and land-saving construction, but also a large share of urban vegetation. A planned unit development (PUD) is a land-use planning instrument that is often used to improve urban quality in urban renewal and densification worldwide. In this study, we analyse the influence of PUDs on urban vegetation in the Canton of Zurich, Switzerland, by contrasting them with conventional zoning. We modelled the share of shrub and tree canopy cover per neighbourhood block using generalized linear mixed effect models (GLMM), with the type of planning instrument as the focal predictor amongst other control variables known from the literature to be influential on urban vegetation. Results show that PUDs are associated with significantly less urban vegetation cover than conventional zoning. This is unexpected and raises concerns. Given how important PUDs are as levers for improving urban quality, their observed inability to promote valuable shrub and tree structures leads us to recommend that good landscape planning and long-term management of (existing and new) urban vegetation be included as an additional standard criterion of high priority in the assessment of future PUDs.

Forest canopy and mistletoe infestation alter the facilitative effects of Juniperus oxycedrus s.l. on woody seedlings on Mount Lebanon (Lebanon)

AbstractQuestionsIn this study we investigated the direct effect of the shrub Juniperus oxycedrus s.l. on Mediterranean woody species regeneration, and how this interaction can be modified by the juniper habit, the forest canopy and/or infestation of the juniper by the plant parasite Arceuthobium oxycedri. We also aimed at identifying species response groups in relation to their ecological requirements and successional strategies.LocationNorth of Mount Lebanon, in Horsch Ehden natural reserve, a humid montane Mediterranean forest.MethodsWe compared the regeneration of all occurring woody species below and outside 111 Juniperus oxycedrus canopies using the random pair sampling method. We calculated eight relative interaction intensity indexes (RIIJuniper) corresponding to the eight treatment combinations of the three factors: forest canopy (forest/gap), mistletoe infestation (with/without) and juniper habit (spreading/erect). We analyzed the RII values at three different levels: community (all species grouped), species group and species.ResultsOverall, the regeneration of the woody community was facilitated by Juniperus oxycedrus. However, the forest cover significantly reduced the facilitative effect of Juniperus oxycedrus when the latter was not infested by Arceuthobium oxycedri. We identified three species response groups (A: highly facilitated; B: slightly facilitated to neutral; and C: neutral) determined by their response to both Juniperus oxycedrus canopy and forest cover. The most facilitated species were shade‐tolerant/drought‐intolerant late‐successional species.ConclusionsThe results suggest the importance of shade tolerance in the complex mechanism of forest regeneration that is also affected by a parasite plant (Arceuthobium oxycedri), which boosts regeneration dynamics under forest cover by reducing shrub canopy cover.

The influence of grass competition and soil moisture on the growth and phenology of Karoo shrubs in the Eastern Upper Karoo

Rainfall in the Nama-Karoo is sporadic and a plant’s ability to access and utilise available soil moisture will determine its ability to persist in the system and to successfully recruit. When summer rainfall in the Eastern Karoo increases, grassiness increases at the expense of shrub canopy cover. This may drive a transition from shrubland toward grassland. The effect of grass–shrub competition on shrub growth and phenology in the Eastern Karoo is not adequately explained by the root–niche separation hypothesis or the succession hypothesis. In an experiment, we measured shrub growth and phenology in the absence (clipping treatment) and presence (control treatment) of grass over the 2017/2018 rainfall season. Grass clipping changed grass species composition over this period, but grass clipping did not benefit shrubs. We found no competitive effect of grasses on shrubs. However, shrub canopy cover showed a strong linear response to soil moisture, as did canopy cover to temperature. Similarly, soil moisture and temperature were important for stem growth and shrub phenology. Patterns of shrub growth and phenology in response to summer and winter rainfall provide important insight for land managers for optimising production while enabling phenological processes that allow recruitment to take place.

Invasive Urban Mammalian Predators: Distribution and Multi-Scale Habitat Selection.

Simple SummaryRestoration of biodiversity in urban green spaces frequently requires eradication or management of invasive species. We aimed to identify fine- and landscape-scale habitat features associated with the presence of five invasive urban mammals (Rattus species, European hedgehogs, mice, and brushtail possums) in three urban green space types (forest fragment, amenity park, residential garden) across three New Zealand cities, and across two seasons, to identify where management effort should be focused. All species were detected in all greenspace types; however, rodents were detected least in residential gardens, possums were detected most often in forest fragments, and hedgehogs least in forest fragments. Proximity of amenity parks to forest patches was positively associated with possum and hedgehog presence and negatively with rats. Conversely, proximity of residential gardens to forest patches was positively associated with rat presence. Management of rats should focus on sites with shrub and lower canopy cover and of mice on sites with herb layer cover, while micro-habitat features were not important for hedgehogs and possums. Rats were most likely to be found in residential gardens with compost heaps. The wide distributions of these species suggest that in order to be successful, ecological restoration must be coordinated, target all green space types, and engage urban residents.A barrier to successful ecological restoration of urban green spaces in many cities is invasive mammalian predators. We determined the fine- and landscape-scale habitat characteristics associated with the presence of five urban predators (black and brown rats, European hedgehogs, house mice, and brushtail possums) in three New Zealand cities, in spring and autumn, in three green space types: forest fragments, amenity parks, and residential gardens. Season contributed to variations in detections for all five taxa. Rodents were detected least in residential gardens; mice were detected more often in amenity parks. Hedgehogs were detected least in forest fragments. Possums were detected most often in forest fragments and least often in residential gardens. Some of this variation was explained by our models. Proximity of amenity parks to forest patches was strongly associated with presence of possums (positively), hedgehogs (positively), and rats (negatively). Conversely, proximity of residential gardens to forest patches was positively associated with rat presence. Rats were associated with shrub and lower canopy cover and mice with herb layer cover. In residential gardens, rat detection was associated with compost heaps. Successful restoration of biodiversity in these cities needs extensive, coordinated predator control programmes that engage urban residents.

Modeling habitat use and potential distribution of kit fox in the Trans‐Pecos, Texas

AbstractManagement of a species requires knowledge of their distribution and the environmental factors that influence their use of an area. The kit fox (Vulpes macrotis) is a small fox species endemic to the threatened desert grasslands of the western United States and northern Mexico. Little information exists on the status and distribution of kit fox in Texas, USA; however, researchers have documented population declines in the closely related swift fox (Vuples velox) in the Texas Panhandle. Therefore, our objectives were to survey areas of potential kit fox habitat using remote trail cameras to determine use and detection rates for kit fox, evaluate and quantify environmental effects on habitat use, and map potential distribution of kit fox habitat throughout the Trans‐Pecos using results from the preceding occupancy analysis. We conducted camera surveys at 732 baited sites from March 2018 to March 2020, with each survey lasting 14 days on average (~10,248 camera‐days). We detected kit fox at 99 of 732 camera survey sites. We divided surveys into 3‐day sampling occasions and fit single‐season occupancy models to test for an effect of sampling occasion and season on detection and for effects of slope, elevation, shrub height, shrub canopy cover, percent litter, percent herbaceous cover, and bare ground on habitat use. Overall detection was 0.31 ± 0.001 (SE) and was influenced by sampling occasion and season, with detection being highest during November to February and earlier in the survey. Mean probability of use for sites was 0.17 ± 0.01 (range = 0.00–0.85) and was influenced by 4 environmental covariates, with the greatest probability of use in areas with gentler slopes, lower elevations, shorter shrubs, and a greater percentage bare ground. We used the most supported model to make a map of predicted habitat use across the Trans‐Pecos region and showed evidence of model fit. Our work provides detailed baseline information on the distribution and environmental relationships of kit fox in the region and can be used to assist with future research and monitoring efforts.

Shading decreases and delays NDVI and flowering of prostrate Arctic shrubs

Increases in shrub growth and canopy cover are well documented community responses to climate warming in the Arctic. An important consequence of larger deciduous shrubs is shading of prostrate plant species, many of which are important sources of nectar and berries. Here, we present the impact of a shading experiment on two prostrate shrubs, Vaccinium vitis-idaea L. and Arctous alpina L., in northern Alaska over two growing seasons. We implemented three levels of shading (no shade, 40% shade, and 80% shade) in dry heath and moist acidic tundra. Plots were monitored for soil moisture content, surface temperature, normalized difference vegetation index (NDVI), and flowering. Shading was shown to, on average, lower surface temperature (0.7 °C to 5.3 °C) and increase soil moisture content (0.5% to 5.6%) in both communities. Both species- and plot-level NDVI values were delayed in timing of peak values (7 to 13 days) and decreased at the highest shading. Flower abundance of both species was lower in shaded plots and peak flowering was delayed (3 to 8 days) compared with controls. Changes in timing may result in phenological mismatches and can impact other trophic levels in the Arctic as both the flowers and resulting berries are important food sources for animals.

Application of L-band SAR for mapping tundra shrub biomass, leaf area index, and rainfall interception

Rapid shrub expansion has been observed across the Arctic, driving a need for regional-scale estimates of shrub biomass and shrub-mediated ecosystem processes such as rainfall interception. Synthetic-Aperture Radar (SAR) data have been shown sensitive to vegetation canopy characteristics across many ecosystems, thereby potentially providing an accurate and cost-effective tool to quantify shrub canopy cover. This study evaluated the sensitivity of L-band Advanced Land Observing Satellite 2 (ALOS-2) data to the aboveground biomass and Leaf Area Index (LAI) of dwarf birch and alder in the Trail Valley Creek watershed, Northwest Territories, Canada. The σ°VH /σ°VV ratio showed strong sensitivity to both LAI (R2 = 0.72 with respect to in-situ measurements) and wet aboveground biomass (R2 = 0.63) of dwarf birch. Our ALOS-2-derived maps revealed high variability of birch shrub LAI and biomass across spatial scales. The LAI map was fed into the sparse Gash model to estimate shrub rainfall interception, an important but under-studied component of the Arctic water balance. Results suggest that on average across the watershed, 17 ± 3% of incoming rainfall was intercepted by dwarf birch (during summer 2018), highlighting the importance of shrub rainfall interception for the regional water balance. These findings demonstrate the unexploited potential of L-band SAR observations from satellites for quantifying the impact of shrub expansion on Arctic ecosystem processes.

Biological Soil Crust Bacterial Communities Vary Along Climatic and Shrub Cover Gradients Within a Sagebrush Steppe Ecosystem.

Numerous studies have examined bacterial communities in biological soil crusts (BSCs) associated with warm arid to semiarid ecosystems. Few, however, have examined bacterial communities in BSCs associated with cold steppe ecosystems, which often span a wide range of climate conditions and are sensitive to trends predicted by relevant climate models. Here, we utilized Illumina sequencing to examine BSC bacterial communities with respect to climatic gradients (elevation), land management practices (grazing vs. non-grazing), and shrub/intershrub patches in a cold sagebrush steppe ecosystem in southwestern Idaho, United States. Particular attention was paid to shifts in bacterial community structure and composition. BSC bacterial communities, including keystone N-fixing taxa, shifted dramatically with both elevation and shrub-canopy microclimates within elevational zones. BSC cover and BSC cyanobacteria abundance were much higher at lower elevation (warmer and drier) sites and in intershrub areas. Shrub-understory BSCs were significantly associated with several non-cyanobacteria diazotrophic genera, including Mesorhizobium and Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium. High elevation (wetter and colder) sites had distinct, highly diverse, but low-cover BSC communities that were significantly indicated by non-cyanobacterial diazotrophic taxa including families in the order Rhizobiales and the family Frankiaceae. Abiotic soil characteristics, especially pH and ammonium, varied with both elevation and shrub/intershrub level, and were strongly associated with BSC community composition. Functional inference using the PICRUSt pipeline identified shifts in putative N-fixing taxa with respect to both the elevational gradient and the presence/absence of shrub canopy cover. These results add to current understanding of biocrust microbial ecology in cold steppe, serving as a baseline for future mechanistic research.

Seasonal habitat utilisation and morphological characteristics of Chamaeleo dilepis on Telperion Nature Reserve, Mpumalanga, South Africa

ABSTRACT Limited information on the habitat utilisation and seasonal activity of flap-necked chameleons (Chamaeleo dilepis) is available. We investigated habitat utilisation, seasonal distribution, and sexual dimorphism of C. dilepis on Telperion Nature Reserve (a privately protected natural area) in South Africa. Seven broad plant habitat units were surveyed for one year, which included a wet and a dry season. Plant species richness and species diversity, woody plant densities and canopy cover were recorded and analysed in each of the habitat units. Location, sex, age class and morphological measurements were recorded for located chameleons. Gravid adult females were found to be significantly heavier and larger than adult males, but no differences were found in size or mass for subadults. The occurrence of hatchlings was significantly influenced by rainfall, whereas minimum temperature had a significant influence on the occurrence of adults and subadults. Hatchlings occurred from mid-December to March in habitats associated with high shrub and grass canopy cover and low plant species diversity. Subadults were located from mid-March to the end of May in woody habitats and adults were located from the end of October until the end of May. Subadult and adult chameleons preferred dense woodland with high tree canopy cover and rockiness with high plant species diversity. The results of this study suggest that C. dilepis on Telperion have seasonal habits influenced by rainfall, minimum temperature and habitat structure.

Direct and indirect relationships between logging intensity and regeneration of two timber species in the Dry Chaco of Argentina

Dry forests with a high abundance of hardwood tree species, such as the Dry Chaco, have a long history of logging practices. Logging intensity can directly affect forest structure, both in the canopy and in the understory, by extracting larger trees, and by damaging the understory. This in turn can impact the regeneration of timber species, showing an indirect effect of logging. However, little is known about these relationships in Neotropical dry forests. In this observational study across 13 sites with different logging histories, we analyze how understory structure (shrub basal area and shrub stem density) and canopy cover are modified by logging intensity (quantified by an index that combines logging selectivity, frequency, and time since the last harvest). In addition, using structural equation models, we evaluate if the regeneration (sapling density) of the two most valuable timber species (Schinopsis lorentzii and Aspidosperma quebracho-blanco) is indirectly related with logging intensity through the modification of the structure of the canopy and the understory. We found that canopy cover and shrub basal area decreased with logging intensity (P = 0.001 and P = 0.016, respectively), while shrub stem density showed no changes (P = 0.48). The density of A. quebracho-blanco saplings was positively related with shrub stem density (P = 0.0033), and tended to be negatively related with shrub basal area (P = 0.09). Therefore, the indirect effect of logging intensity on A. quebracho-blanco regeneration, by modifying the shrub basal area, tended to be positive, although the magnitude was quite low. None of the variables considered showed a relationship with regeneration of S. lorentzii. Our results indicate that logging intensity does not negatively affect regeneration of key tree species of the Dry Chaco, nor the density of shrubs. Moreover, shrub basal area and canopy cover may recuperate after a considerable rest period since the last logging event. Together, these results suggest that woody plants in the Dry Chaco forest might be resilient to forestry practices. We propose that logged dry forests must rest decades to recover their structure in canopy cover and shrub basal area. Including other attributes (e.g. soil, fauna and interactions) is necessary to better understand the possible influence of logging intensity on the ecological integrity and sustainability of dry woodlands like Chaco forests.

Building selection by the common brushtail possum (Trichosurus vulpecula)

Abstract ContextThe common brushtail possum (Trichosurus vulpecula) is a protected native species in Australia that can access buildings in urban areas and cause considerable damage or disruption to building occupants. Although several strategies to discourage this species from entering buildings have been recommended, few have been evaluated empirically. AimsOur study aims to analyse how landscaping and building construction influence occupancy of buildings by the common brushtail possum. MethodsWe collated reports of possums occupying 134 buildings over 12 years on the campus of The Australian National University (ANU), in the Australian Capital Territory (ACT). We used generalised linear modelling (GLM) to identify associations between the total number of reported possum-related incidents for buildings and a range of landscape and building characteristics. Key resultsControlling for the effect of building size, we found that the number of reported possum-related incidents in buildings was positively associated with the percentage of tree and shrub canopy cover within the calculated home-range buffer distance of 49m from buildings, length of canopy overhanging roofs and building age, and negatively associated with tree species richness and number of trees with natural hollows and nest boxes within 49m of buildings. There were likely to be more possum-related reports from buildings in areas where the dominant tree genus was native, buildings with parapets (walls extending above the roof), buildings with structures penetrating from the roof, buildings with tile roofs and gable roofs. ConclusionsA combination of suitable habitat surrounding buildings, suitable access to the roofs of buildings and weak points in building roofs (e.g. parapets, roof penetrations), makes them more vulnerable to occupancy by the common brushtail possum. Implications Our results provided clues for managing existing buildings, or designing new buildings, in a way that may reduce the likelihood of occupancy by the common brushtail possum. Our study also demonstrated how building-maintenance records can be used to address human–wildlife conflict over time.

Application of Ground-Based Lidar and Gap Intercept Measurements to Quantify a Shrub Configuration Metric within Greater Sage-Grouse Nesting Habitat

Vegetation composition (i.e., relative proportion of species) and configuration (i.e., horizontal and vertical arrangement of the plant components) in sagebrush-steppe ecosystems are fundamental determinants of the suitability of nesting habitat for Greater Sage-Grouse (Centrocercus urophasianus). The spatial arrangement of shrub and herbaceous canopy cover conceals Greater Sage-Grouse from predators and protects the nest from natural hazards, and gaps in vegetative cover provide escape routes for hens. Most sage-grouse habitat studies quantify vegetation composition, but few quantify habitat configuration at fine scales. We used ground-based lidar (light detection and ranging) data from Greater Sage-Grouse nesting habitat to test the applicability of a metric calculated from the traditional canopy gap intercept measurements to quantify shrub canopy configuration (shrub patchiness). Vegetation surveys were conducted on 30 randomly selected nest and non-nest sites (15 of each); we acquired high-resolution ground-based lidar data for 12 plots at 3 nest locations. Variation in canopy gap size was used as a metric to represent shrub configuration characteristics. We measured the variability in gap size among shrubs within lidar point cloud data sets using a lacunarity index at multiple scales. We measured variability of gaps from line transects by calculating the variance to mean-square ratio of gap size. Correlations (r) between measures of gap size variation from the 2 techniques ranged from 0.76 to 0.83 (r2 = 0.58–0.69). Our results support the use of canopy gap intercept measures to quantify configuration (patchiness) of shrub cover and thus complement vegetative composition metrics. Gap sizes were more variable at nest sites than at non-nest sites, suggesting that gap size variability may be a useful vegetative configuration metric to characterize sage-grouse nesting habitat. The fine-scale habitat metrics we evaluated provide a more refined tool for land managers to characterize local variation in wildlife habitat within shrubland ecosystems and can be derived from the existing gap intercept data.

Response of Polygonatum Multiflorum and P. Odoratum morphological Characteristics and Population Structure to Variation in Environmental Factors

AbstractThe morphological variation and population structure were studied in seven populations of Polygonatum multiflorum and 19 populations of P. odoratum. The mean number of flowers per shoot and per inflorescence as well as inflorescence number per shoot in both species correlated negatively with total tree and shrub canopy cover, while the mean number of flowers per inflorescence in P. odoratum correlated positively with the soil pH. The shoot density and life stage composition in P. odoratum populations depended on total tree and shrub canopy cover, which negatively correlated with the density of generative shoots in populations of both species. The results of this study revealed the crucial effect of light availability expressed via total tree and shrub canopy cover in the habitats of Polygonatum species to their flowering intensity and population structure.

Non‐native grasses reduce scaled quail habitat

ABSTRACTNon‐native grasses are frequently sown in the southwestern United States for livestock forage and erosion control. These grasses often spread from areas where they are planted and replace native grasses and forbs. We tested the hypothesis that chestnut‐bellied scaled quail (Callipepla squamata castanogastris) avoid locations dominated by non‐native grasses. We trapped scaled quail at 5 different sites in southern Texas, USA, and located quail fitted with necklace‐style transmitters 3 times/week during 2013–2014. We manually delineated plant communities using aerial maps and on‐the‐ground knowledge of the study sites. We examined second‐order (home‐range scale) selection by comparing proportion of the areas of plant communities within 62 scaled quail home ranges (used) paired with random home ranges (available). We examined third‐order (within‐home‐range scale) selection by comparing the composition of bird location (used) and random (available) points based on proportion of points within plant communities. For both home‐range scale and within‐home‐range scale analyses, we used non‐parametric multivariate analysis of variance with 9,999 random permutations. We examined fourth‐order (organism‐centered) selection by measuring vegetation variables at used and available locations and then estimating the relative probability of use of vegetation variables and by estimating continuous selection functions for variables that were influential in determining relative probability of use. Buffelgrass (Pennisetum ciliare) and Old World bluestems (Bothriochloa spp., Dichanthium annulatum and other Dichanthium spp.) comprised 99% (95% CI = 98–100%, n = 143 sites where non‐native plants occurred) of the non‐native grasses in our study areas. Scaled quail avoided non‐native and riparian plant communities at the home‐range and within‐home‐range scales of selection. At the organism‐centered scale of selection, odds of use by scaled quail decreased 28% for every 10% increase in non‐native grass cover and increased 12% for every 10% increase in shrub canopy cover. Scaled quail avoided locations with >10% canopy cover of non‐native grasses. Based on avoidance at 3 scales of selection, dominance of buffelgrass and Old World bluestems degrades habitat for scaled quail. Spread and sowing of non‐native grasses and brush clearing may be partly responsible for declines in scaled quail populations. © 2019 The Wildlife Society.

Linking White‐Tailed Deer Density, Nutrition, and Vegetation in a Stochastic Environment

Linking White‐Tailed Deer Density, Nutrition, and Vegetation in a Stochastic Environment

Browsing evidence of the native and near-threatened Pudu puda deer in restoration plantings on Chiloé Island, Chile

Few studies have focused on the actual extent and spatial patterns of browsing in relation to forest restoration, especially when browsing is done by deer with conservation status. Here, we present data from three forest restoration experiments located in priority forests for restoration in Chiloe Island in Chile. The aim of this study is to report evidence of browsing of the southern pudu (Pudu puda), a native and Near Threatened deer species. We visually assessed browsing for all individual seedlings and calculated the average browsing extent per plot and treatment. Since pudus as well as other deer species are known to preferably feed in open spaces, we hypothesized that Pilgerodendron uviferum planted seedlings will present higher browsing rates in places with lower shrub cover (bogs) and canopy cover (upland areas) (H1). In the case of degraded North-Patagonian forests we hypothesized that Nothofagus nitida planted seedlings will present higher browsing rates in places with higher %PPFD (Photosynthetic Photon Flux Density) and/or lower residual basal area (H2). Our results indicate that browsing ranged from 9.3% up to 84.0% depending on tree species and site condition. In burned forests, browsing was significantly higher (p < 0.01) when shrubs were removed (84.0% ± 9.9) than by retaining them (68.9% ± 11.6). In degraded old-growth forests, we found significantly higher browsing in places with higher degradation (p < 0.05). Furthermore, %PPFD was significantly correlated with browsing (rho: 0.535; p < 0.01). Based on our results, forest restoration efforts in Chiloe Island will face a great challenge in balancing the protection of Near Threatened wildlife and the restoration of tree species with conservation problems, especially in open/disturbed areas, where higher browsing was found.

Soil characteristics are associated with gradients of big sagebrush canopy structure after disturbance

AbstractReestablishing shrub canopy cover after disturbance in semi‐arid ecosystems, such as sagebrush steppe, is essential to provide wildlife habitat and restore ecosystem functioning. While several studies have explored the effects of landscape and climate factors on the success or failure of sagebrush seeding, the influence of soil properties on gradients of shrub canopy structure in successfully seeded areas remains largely unexplored. In this study, we evaluated associations between soil properties and gradients in sagebrush canopy structure in stands that had successfully reestablished after fire and subsequent seeding treatments. Using a dataset collected across the Great Basin, USA, of sagebrush stands that had burned and reestablished between 1986 and 2013, we tested soil depth and texture, soil surface classification, biological soil crusts plus mean historical precipitation, solar heatload, and fire history as modeling variables to explore gradients in sagebrush canopy structure growth in terms of cover, height, and density. Deeper soils were associated with greater sagebrush canopy structure development in terms of plant density and percent cover, coarser textured soils were associated with greater sagebrush cover and density, and more clayey soils were typically associated with greater height. Biological crust presence was also positively associated with enhanced sagebrush canopy growth, but adding more demographically or morphologically explicit descriptions of biocrust communities did not improve explanatory power. Increasing heatload had a negative effect on sagebrush canopy structure growth, and increased mean annual precipitation was only associated with greater sagebrush height. Given that conservation and restoration of the sagebrush steppe ecosystems has become a priority for land managers, the associations we identify between gradients in post‐fire sagebrush canopy structure growth and field‐identifiable soil characteristics may improve planning of land treatments for sagebrush restoration and the understanding of semi‐arid ecosystem functioning and post‐disturbance dynamics.