Livestock Disturbance Research Articles

Impacts of livestock grazing on blue‐eared pheasants (Crossoptilon auritum) survival in subalpine forests of Southwest China

AbstractThe degradation and fragmentation of natural habitats, driven largely by anthropogenic activities such as grazing, represent growing concerns in environmental conservation. We examined the impact of grazing activities on the survival of the blue‐eared pheasant Crossoptilon auritum, a ground‐nesting bird endemic to subalpine forests. Using camera‐trapping and artificial nest experiments, we compared two sites in Sichuan, China: Wanglang (high grazing intensity) and Jiuzhaigou (no grazing) national nature reserves. The study, conducted from 2017 to 2021, evaluated habitat suitability changes for these pheasants and examined the impact of grazing on nesting success by conducting a nest predation experiment. The results of our study showed that (1) since the significant increase of free‐ranging livestock post‐2014, the area of most suitable and moderately suitable habitats for blue‐eared pheasants in Wanglang decreased by 14.28% (net loss 15.12 km2); (2) predominant natural predators of the pheasant, such as yellow‐throated martens (Martes flavigula) and leopard cats (Prionailurus bengalensis), were mostly observed to be spatially distant from livestock; (3) the pheasant's nesting failure rate was 2.18 times higher in Wanglang than in Jiuzhaigou; (4) high‐intensity livestock disturbance correlated with decreased food resources for pheasants, yet resulted in an increased abundance of Coleopteran insects. These results illustrate a complex dynamic: Although forest pheasants, such as the blue‐eared pheasant, may initially benefit from the presence of livestock through increased predator refuge and access to specific food resources, they ultimately face greater risks. These include a significant increase in nest failure rates and remarkable habitat loss and degradation. In light of these results, we advocate for strict control and management of grazing activities inside reserves. Additionally, we recommend the implementation of a systematic monitoring program that focuses on the population dynamics and habitat use of endangered pheasants in Southwest China.

Fine-Scale Interactions between Leopard Cats and Their Potential Prey with Contrasting Diel Activities in a Livestock-Dominated Nature Reserve.

Habitat use and the temporal activities of wildlife can be largely modified by livestock encroachment. Therefore, identifying the potential impacts of livestock on the predator-prey interactions could provide essential information for wildlife conservation and management. From May to October 2017, we used camera trapping technology to investigate fine-scale spatiotemporal interactions in a predator-prey system with the leopard cat (Prionailurus bengalensis) as a common mesopredator, and its prey with contrasting activity patterns (i.e., nocturnal rats and diurnal squirrels) in a livestock-dominated nature reserve in Northern China. We found that the prey species showed different habitat preferences with the leopard cats. The nocturnal rats had strong positive effects on the site-use of the leopard cats, while the influence of livestock on the diurnal squirrels' site-use changed from strong positive effects to weak effects as the livestock disturbance increased. The temporal overlap between the leopard cats and the nocturnal rats was almost four times that of the leopard cats and the diurnal squirrels, regardless of the livestock disturbance. Our study demonstrated that the fine-scale spatiotemporal use patterns of the leopard cats were consistent and highly correlated with the nocturnal rats under livestock disturbance. We suggest that appropriate restrictions on livestock disturbance should be implemented by reserve managers to reduce the threat to wildlife and achieve multi-species coexistence.

Free-ranging livestock altered the spatiotemporal behavior of the endangered North Chinese leopard (Panthera pardus japonensis) and its prey and intensified human-leopard conflicts.

Widespread distribution of livestock in the natural habitats of large carnivores may negatively impact carnivore populations by reducing wild prey availability and increasing human-carnivore conflicts. In this study, we used camera-trapping data collected in the temperate forests of the Taihang Mountains in North China during 2016-2019 to examine whether and how free-ranging cattle affected habitat use and Diel activity patterns of the endangered North Chinese leopard (Panthera pardus japonensis) and its 2 wild prey species, Siberian roe deer (Capreolus pygargus), and wild boar (Sus scrofa). Residents were also interviewed to record livestock depredation events by leopards during 2015-2019. We found that roe deer spatially avoided sites frequented by cattle, but wild boar did not. In the growing seasons, leopards shared habitats with cattle and tended to increase their diurnal activities where cattle were present. All 3 study species exhibited fine-scale spatial-temporal segregation to cattle. Leopards selectively preyed on calves over adult cattle and livestock depredation frequency was positively correlated with the detection rates of cattle and wild prey, but not that of leopard. These findings not only show that through behavioral adaption large carnivores and their ungulate prey may persist under livestock disturbance, but also highlight how important proper livestock management is for conserving North Chinese leopards in this region. To enhance livestock management and mitigate human-leopard conflicts, we recommend specific actions, such as better guarding of free-ranging cattle or adoption of a captive farming system.

Sedimentary DNA and molecular evidence for early human occupation of the Faroe Islands

The Faroe Islands, a North Atlantic archipelago between Norway and Iceland, were settled by Viking explorers in the mid-9th century CE. However, several indirect lines of evidence suggest earlier occupation of the Faroes by people from the British Isles. Here, we present sedimentary ancient DNA and molecular fecal biomarker evidence from a lake sediment core proximal to a prominent archaeological site in the Faroe Islands to establish the earliest date for the arrival of people in the watershed. Our results reveal an increase in fecal biomarker concentrations and the first appearance of sheep DNA at 500 CE (95% confidence interval 370-610 CE), pre-dating Norse settlements by 300 years. Sedimentary plant DNA indicates an increase in grasses and the disappearance of woody plants, likely due to livestock grazing. This provides unequivocal evidence for human arrival and livestock disturbance in the Faroe Islands centuries before Viking settlement in the 9th century.

Responses of forest structure, functions, and biodiversity to livestock disturbances: A global meta-analysis.

Habitat degradation and land-use change driven by the livestock sector are among the major causes of global biodiversity loss. Forests are crucial in maintaining biodiversity and mitigating climate change. Apart from continuing deforestation, forests also face increasing pressure from livestock grazing in the system, which is less understood compared to grasslands. Through a meta-analysis of 156 articles with 1936 data entries, this study assesses the effect of livestock on forest biodiversity, structure, and functions, varying with livestock types, livestock density, grazing history, and climatic factors. Our results show that livestock overall had a negative impact on the forest structure and functions, reduced species abundance but increased richness. Medium and large mammals, plant communities, and soil were more negatively affected compared to other groups such as birds and invertebrates. Livestock also influenced the role of forests in mitigating climate change. They changed forest carbon stock by reducing plant biomass; however, they did not significantly impact the soil carbon stock or soil greenhouse gas emissions. Ecosystem attributes were more affected in warmer and drier regions and by single species grazing than the mixed grazing. Past livestock grazing history moderates the impacts of livestock, with the strongest negative effect occurred with a history of 1-5years. Nonetheless, livestock activities also had a positive impact on forest management, such as reducing forest flammability. Our results also indicate the lack of studies on how higher trophic levels respond to livestock disturbances and how grazing intensity moderates the effect, which includes grazing duration and livestock density. The complex responses of forests to livestock in different conditions call for more adaptive management depending on the conservation targets and evolution history.

Importance of Phytobiomass and Ungulates to Hydrologic Function in a Temperate Grassland

Hydrologic dysfunction associated with desertification of grazing lands likely depends on two opposing biophysical drivers, compaction by livestock and bioturbation by plant roots and soil biota. To understand which is most important, we conducted a long-term field experiment. We tested the effects of phytobiomass (control vs. herbicide treated) and three ungulate disturbance treatments (none, once, and twice disturbed) on soil water transport in northern mixed-grass prairie. Field-saturated hydraulic conductivity (i.e., infiltration) was primarily reduced by the most severe (twice disturbed) ungulate disturbance treatment. To a lesser degree, ungulate disturbance and phytobiomass interacted, and similar levels of hydrologic dysfunction were detected for plots annually treated with herbicide and disturbed by a single livestock disturbance event (and while soils were dry and resistant to compaction) and naturally vegetated plots that had been twice disturbed (including while soils were wet and susceptible to compaction). Our findings suggest hydrologic dysfunction in grazing lands is mainly due to compaction by ungulates, especially when grazing at high stocking rates and while areas are vulnerable to compaction (e.g., fine soils, wet soils, not well vegetated).

Livestock and Small-Scale Irrigation Scheme Interactions as a Key Source for Sedimentation during the Irrigation Season: Four Case Studies from South-West Shoa, Ethiopia

Small-scale irrigation (SSI) development can play a major role in Ethiopia’s economic development, but sedimentation is a major threat to its sustainability. The focus of the dominant discourse around the sedimentation of SSI schemes lies in upstream catchment protection during the rainy season, neglecting both protection against erosion through overland flow along the margins of the canal network and sedimentation caused by livestock disturbances. Remedies against the latter causes of sedimentation during the irrigation season have been ineffective due to erroneous assumptions regarding its cause. This study aimed to identify the sources and extent of sedimentation in SSI schemes. The accumulated sediment in the canal pre-irrigation season was measured from four SSI schemes and suspended sediment samples during irrigation season were collected from one SSI scheme. The accumulated sediment in the canal pre-irrigation season was measured from four SSI and suspended sediment samples during irrigation season were collected from one SSI scheme. The extent of sedimentation in the canals during the pre-irrigation season in relation to canal capacity was 100% of lined and unlined canals in abandoned, 68% in a lined, and 84% unlined canals in heavily sedimented and 38% in a lined and 46% of unlined canals lightly sedimented schemes. Livestock interactions with the SSI schemes were found to be the major sediment source before and during the irrigation, hence, attention should be given to integrating livestock as a part of the system.

Effects of free-ranging livestock on sympatric herbivores at fine spatiotemporal scales

Livestock grazing is one of the most widespread types of anthropogenic land use, even occurs in many protected areas and has become a threat to wildlife worldwide. Understanding livestock-wildlife interactions is crucial for rare large carnivores conservation. In China, free-ranging cattle within forests degrade the habitat of the tigers (Panthera tigris) and leopards (Panthera pardus), but quantitative assessments of how livestock affect the spatial and temporal use by the major ungulate prey of the two endangered felids are very limited. This study aimed to examine the interactions of several sympatric wildlife species with livestock at a fine spatiotemporal scale in a human-dominated forest landscape. Based on a large-scale camera-trapping data across the China-Russia border, we used N-mixture models, two-species occupancy models and activity pattern overlap to understand the effects of cattle grazing on three ungulate species (sika deer Cervus nippon, wild boars Sus scrofa and roe deer Capreolus pygargus). Spatially, with cattle activity increasing, wild boar and roe deer had different degrees of decline in the intensity of habitat use. Sika deer were displaced as more cattle encroached on forest habitat. Temporally, in the presence of cattle, wild boar and sika deer decreased their activities in the day. In addition, three wild ungulates trend to exhibit lower spatiotemporal overlap with cattle at shared camera sites. Our study shows that wildlife species may reduce the probability of habitat use by spatial avoidance and changing the daily activity patterns. We underscore that fine-scale (i.e. camera-site level) spatiotemporal avoidance is likely a key component of co-occurrence between livestock and the sympatry of competing ungulates inhabiting forest ecosystems. Given prey were depressed, efforts to minimize the livestock disturbance on these species need to be considered to ensure their sustained recoveries.

How Cattle and Wild Ungulate Use of Riparian Areas Effects Measures of Streambank Disturbance

Improper management of cattle near streams can negatively affect the processes that support stream and riparian ecosystems. To judge the success of riparian management strategies, public land management agencies often evaluate two metrics of livestock disturbance, stubble height and streambank alteration. There are concerns associated with how well these disturbance metrics reflect livestock use and incorporate additional effects due to wild ungulates. We sought to address these questions in 39 riparian areas by using time-lapse cameras to estimate ungulate use and then measuring near stream ungulate disturbance in these same reaches. We found daytime measures of livestock use were related to stubble height and streambank alteration. Explaining the variation in the relationship between stubble height and livestock use was improved by incorporating covariates, whereas covariates did little to improve our understanding of streambank alteration. This suggests greater flexibility in how different stream reaches are managed when stubble height is the guideline. As streambank alteration was explained solely by ungulate use, the simplest way to reduce disturbance was to reduce use. In most stream reaches, the additive presence of wild ungulates was minimal but sufficient to be included in the best models describing the effects of ungulate disturbance. On most days, no cattle were seen in the evaluated riparian reaches. Although large groups of cattle (> 20 individuals) were occasionally observed within riparian areas, they generally occurred in small groups of one to four individuals. Across the riparian reaches we evaluated, cattle presence and density were generally low enough that metrics of livestock disturbance suggested little risk to stream conditions important to aquatic biota. However, there were some riparian areas where cattle stayed too long or occurred in large enough numbers that their use along the streambanks could negatively affect stream habitat conditions.

Using Stubble Height to Monitor Livestock Disturbance Near Streams: How a Recent Critique is Relevant to the Protection of Cold-water Salmonids

On the Ground • The measurement of utilization and residual vegetation (stubble height) is a valuable tool in managing livestock disturbance but it is often improperly measured, and results misinterpreted. A common situation for these concerns is when stubble height protocols and rationales used for terrestrial areas are applied to riparian zones and the protection of fish habitat. • Protocols used to assess stubble height near streams and serve as a surrogate for fish habitat may differ from approaches used to protect upland plant vigor. Measurements of stubble height designed to protect fish habitat can include the measurement of all herbaceous vegetation along the greenline and should be evaluated following the removal of livestock and after the growing season ends. • In allotments with threatened salmonids or other at-risk aquatic species, stubble heights necessary to protect fish habitat may exceed what is necessary to maintain forage production for livestock. Properly determined and applied near stream stubble height standards can protect important fish habitats while providing accountability for grazing management. Consistent livestock management above standards will improve salmonid habitats and undermine arguments used by organizations that would like to limit livestock grazing on public lands. • If range conservationists and fisheries biologists work together to develop monitoring protocols for stubble height or other metrics that can be used to improve fish habitat, the application of proper standards to manage livestock disturbance near streams should benefit the fish, the land management agencies, and the ranchers that rely on grazing public lands.

Tiger and leopard co-occurrence: intraguild interactions in response to human and livestock disturbance

Intraguild interactions have important implications for carnivore demography and conservation. Differences in how predators respond to different forms of disturbance might alter their interaction patterns. We sought to understand how human and livestock disturbance impact co-occurrence of sympatric large carnivores such as tiger (Panthera tigris) and leopard (P. pardus) and thereby mediate the intraguild interaction pattern to enable coexistence of the species in a human-dominated landscape. We surveyed 361 locations in Chitwan National Park, Nepal, to examine how prey abundance and disturbance factors such as human and livestock presence might influence habitat use by tigers and leopards independently and when co-occurring. Single-species single-season models and two-species single-season models were developed to examine hypotheses on unconditional detection and occupancy and species interaction respectively. Pervasive human use of the park had negative impacts on tiger occupancy while the abundance of prey had a positive influence. Despite significant prey overlap between tigers and leopards, none of the native prey species predicted leopard habitat occupancy. However, habitats used extensively by livestock were also used by leopards. Further, we found strong evidence of intraguild competition. For instance tiger occupancy was higher in prey-rich areas and leopard occupancy was low in the sites where tigers were present. These findings, and a species interaction factor of < 1 clearly indicate that leopards avoid tigers, but their use of areas of disturbance enables them to persist in fringe habitats. We provide empirical evidence of how intraguild interaction may result in habitat segregation between competing carnivores, while also showing that human and livestock use of the landscape create disturbance patterns that facilitate co-occurrence of the predators. Thus, because large carnivores compete, some disturbance may mediate coexistence in small protected areas. Understanding such interactions can help address important conservation challenges associated with maintaining diverse carnivore communities in small or disturbed landscapes.

Landscape controls on the distribution and ecohydrology of central Oregon springs

AbstractSmall springs in semiarid landscapes are essential for maintaining aquatic biodiversity and supporting livestock grazing operations. However, little is known about controls on the distribution and physical characteristics of small springs, the aquatic species they support, or their sensitivity to disturbance. We address this information gap in the Crooked River subbasin, a tributary of the Deschutes River in Oregon. We conducted spatial analyses on 2,519 mapped springs to investigate the influence of landscape controls (precipitation and bedrock permeability) on spring density in the Crooked River subbasin and the adjacent Upper Deschutes subbasin. Spring density was highest in areas of low bedrock permeability (P &lt; 0.0001) and high annual precipitation (P &lt; 0.0001). We suggest that the high density of small springs on low‐permeability bedrock indicates that these springs generally have short, shallow flow paths and thus may be susceptible to forecasted climate changes. A survey of 137 springs in the Crooked River subbasin revealed the hydrogeologic setting affects spring discharge type (P = 0.017), temperature (P = 0.011), and pH (P = 0.026). We found a high frequency of anthropogenic impacts on springs: 95% of diffuse‐discharge springs and 79% of discrete‐discharge springs were disturbed by livestock grazing. Species inventories at 10 of the most intact surveyed springs confirm that small springs are biologically diverse, with 151 total species of plants and 135 total taxa of macroinvertebrates. Springs in the Crooked River subbasin are ecologically important habitats but require careful management to protect against livestock disturbance and development.

The influence of age- and sex-specific labor demands on sleep in Namibian agropastoralists

ObjectiveTo understand the basics of sleep quality in a pastoralist population and to explore predictors of this variation. DesignCross-sectional. SettingNorthern Namibia, dry seasons of 2016 and 2017. ParticipantsThe Himba, a nonindustrial seminomadic agropastoralist population without access to the electrical grid. MeasurementsUsing Actiwatch-2 devices, 75 participants completed 721 days of wear. We calculated sleep duration, efficiency, and activity counts before and after sunset/sunrise and onset/offset. Participants were also interviewed about sleeping arrangements and nighttime disruptions. ResultsHimba show lower sleep duration and efficiency than other populations studied, and men had substantially lower duration and efficiency than women. Sex differences were not attenuated when napping was included with total sleep time. Age predicted longer sleep duration and lower evening and morning activity levels. Number of adult co-sleepers predicted increased sleep duration and efficiency in women. Livestock disturbance was not a commonly reported cause of nighttime waking. ConclusionsThese findings support predictions that pastoralist groups may have lower sleep quality than other subsistence populations, but this does not appear to be a consequence of noise from livestock. Instead, lower sleep quality appears to be the result of subsistence and social activities, particularly for men and young adults overall.

The Relationship Between Measures of Annual Livestock Disturbance in Western Riparian Areas and Stream Conditions Important to Trout, Salmon, and Char

Managing livestock disturbance in riparian zones in a manner that provides economic returns to ranchers while protecting streams is an important aspect of rangeland management on public lands in the western United States. Attempts to balance economic and ecologic outcomes have been made more difficult due to the presence of several salmonid species that are protected under the Endangered Species Act. One approach to proper management of livestock use near streams has been to define the allowable limits of disturbance using 2 metrics, streambank alteration and stubble height. We evaluated 153 stream reaches within the Interior Columbia Basin to determine if these 2 surrogates of livestock disturbance measured after the vegetative growing season were associated with stream conditions important to salmonids evaluated the following summer. We found that each stream habitat attribute that was evaluated (width-to-depth ratio, streambank angle, percent undercut banks, streambank stability, residual pool depth, percent pools, percent pool-tail fine sediments <2 mm, and wood frequency) trended toward lower-quality salmonid habitat as streambank alteration increased or as stubble height decreased. While the strength of these associations were variable, the slopes of the relationships suggest that managing the amount of streambank alteration or stubble height could influence stream conditions within the Interior Columbia Basin. Because improved stream conditions for salmonids corresponded to decreased livestock disturbance, the amount of disturbance allowed in a stream reach will need to reflect management expectations and the environmental setting within the allotment. As a starting point, we suggest the continued application of existing livestock disturbance standards in stream reaches with good habitat conditions, and the specification of more conservative disturbance standards in stream reaches that have degraded habitat conditions.

The Effect of Community-Based Soil and Water Conservation Practices on Abundance and Diversity of Soil Macroinvertebrates in the Northern Highlands of Ethiopia

Soil and water conservation (SWC) practices in the northern highlands of Ethiopia have important implications for land restoration and biodiversity recovery. The present study determined soil macroinvertebrate (SMI) abundance and diversity in response to spatial conditions i.e., generated by different conservation practices, soil depth, and temporal seasonality with the wet and dry season. The SWC practices considered were exclosure + terrace, exclosure alone, terraces, and non-conserved grazing lands. Each SWC measure was selected in three sites that were considered as replications due to low heterogeneity in terms of human and livestock disturbances and biophysical factors. Soil macroinvertebrates were collected using a monolith according to tropical soil biology and fertility (TSBF) method. The highest density (55%) of SMI was found in exclosures followed by terraces 26%. Non-conserved communal grazing lands account for only 19% of the total. Shannon diversity index was significantly (P &lt; 0.05) higher (1.21) in the exclosures supported with terraces and the lowest (0.9) was observed in the non-conserved communal grazing lands. Diversity was also significantly (P &lt; 0.05) higher (1.26) in wet than dry season (0.70). The highest (41%) Sorensen similarity index among SMI was found between exclosures with terraces and exclosures alone during the wet season. The lowest (20%) Sorensen similarity index was found between terraces alone and exclosures with terraces in dry season. Soil macroinvertebrate abundance was higher in upper (0–10 cm) than lower (10–20 and 20–30 cm) soil depth. Soil macroinvertebrate abundance was positively and strongly correlated with soil moisture (R2 = 0.85) and soil organic carbon stock (R2 = 0.95). However, it was negatively (R2 = −0.71) correlated with bulk density. Generally, the abundance and diversity of SMI increased as exclosures and communal grazing lands are supported with terraces.

Livestock disturbance in Brazilian grasslands influences avian species diversity via turnover

Managing ecological disturbances at different spatial scales is paramount for maintaining or restoring faunal diversity in grasslands. Whereas some studies have reported varying net effects of livestock disturbance intensity upon species richness in grasslands, most analysis reveal strong effects on beta-diversity. However, beta-diversity can be further partitioned into a nestedness and turnover components, which allows complementary insights on the effects of disturbance on biodiversity across spatial scales. Here we tested for differences in avian species richness and beta-diversity across three intensity levels of livestock disturbance in southern Brazilian grasslands under commercial livestock production. We also tested how disturbance influences the nestedness and turnover components of beta-diversity separately. We found no difference in rarified-extrapolated species richness between disturbance levels. In contrast, we found a significant difference in species composition between disturbance levels, which was attributable to the turnover, but not to the nestedness component. Specifically, livestock disturbance had a predictable effect upon beta-diversity, with turnover of species composition occurring along the gradient of vegetation height in pastures. Our study illustrates the importance of differentiating the turnover and nestedness components of beta-diversity to detect effects of disturbance gradients on biodiversity patterns. We argue that conservation strategies should focus on preserving the mosaic of short- and tall-grass physiognomies associated with the disturbance gradient imposed by livestock production.

Divergent responses of sympatric species to livestock encroachment at fine spatiotemporal scales

Livestock are a major human-induced threat to wildlife worldwide, especially in forest landscapes where livestock degrade the food and habitat of forest-dwelling wildlife. However, few empirical studies on this topic have been conducted at fine spatiotemporal scales that are crucial for wildlife-livestock interactions, in particular those involving multiple sympatric wildlife species under policy changes. Here, we demonstrate wildlife-livestock interactions through examining the interactions of several sympatric, threatened wildlife species with livestock in Wolong Nature Reserve, China, using data collected from infrared camera traps, DNA analysis of panda fecal samples and panda distribution predictive modeling along with habitat predictors. Camera trapping revealed an increase in livestock after the government implemented an incentive policy to encourage livestock production midway through the study. Three species (giant panda, red panda, and golden snub-nosed monkey) were displaced as more livestock encroached on forest habitat. In contrast, the detection rate of sambar deer was not affected by livestock encroachment, but sambar shifted the timing of visiting water sources (streams) to dusk (when livestock disturbance and other human activities were lower). The number of giant pandas detected via DNA testing of feces was relatively stable, but panda distribution modeling showed that pandas occurred across a wider area after disturbance. Our research shows that with increased livestock, different wildlife species may respond in different ways, which is likely associated with their biological traits (e.g., life history strategy and diet). Our study underscores the need for careful livestock policy making and planning.

Invasive spread dynamics of Anthriscus caucalis at an ecosystem scale: propagule pressure, grazing disturbance and plant community susceptibility in canyon grasslands

Several factors may influence invasive spread dynamics once a species becomes naturalized. Propagule pressure generated from established populations is likely mediated by local scale factors such as plant community characteristics and disturbance regimes as well as ecosystem scale factors such as landscape features that shape dispersal patterns and propagule availability. Using a multi-scale observational approach, we explore how propagule pressure generated from naturalized populations of Anthriscus caucalis (M.-Bier) influences invasive spread dynamics in the Snake River canyon grassland ecosystem of the Intermountain Pacific Northwest, USA. In this study, we utilize demographic insights into A. caucalis naturalization across plant communities and a companion ecosystem scale distribution survey to elucidate invasive spread dynamics using spatially-explicit SDMs. We modeled A. caucalis occurrence as a function of plant community type, grazing disturbance, and propagule pressure generated from high-shrub communities. A. caucalis was almost uniformly present in low- and high-shrub (>90 %) communities. Within bunchgrass communities, A. caucalis occurrence was significantly lower within grazed paddocks (3 %) compared to ungrazed paddocks (52 %). The probability of A. caucalis occurrence in bunchgrass communities within ungrazed paddocks also increased at a faster rate as the relative area of high-shrub communities increased. These results suggest propagule pressure generated from high-shrub communities strongly influence invasive spread into bunchgrass communities. Our results also suggest that livestock disturbance slows invasive spread by decreasing propagule supply from high-shrub communities. Plant community composition also contributed to A. caucalis occurrence patterns within bunchgrass communities. A. caucalis occurrence declined as native bunchgrass cover increased, whereas occurrence increased with increasing cover of exotic annual species. As native bunchgrass cover declined, A. caucalis occurrence increased in locations with greater relative area of high-shrub communities. These results suggest that undisturbed bunchgrass communities are resistant to A. caucalis invasion regardless of propagule supply. In disturbed bunchgrass communities dominated by exotic annuals, A. caucalis invasion levels were positively associated with increased propagule pressure generated from high-shrub communities. In conclusion, the coupling of comparative demographic observations with spatially-explicit SDMs yielded significant insights into invasive spread dynamics. This approach should be applicable for elucidating invasive spread dynamics of other invading plant species and ecosystems.

Spatiotemporal dynamics of natural tree regeneration in unmanaged subalpine conifer forests with high wild ungulate densities

Increasing wild ungulate populations in the northern hemisphere led to extensive research on their influence on forest regeneration. According to the results of different studies, high ungulate densities may alter forest structure and composition, as well as inhibit forest regeneration. However, little is known about the long-term impact of large herbivores on forest dynamics at the landscape scale. Therefore, we studied forest regeneration in conifer forests of the highly protected Swiss National Park. We assessed sapling densities and apical shoot loss by repeated systematic sampling in 2003 and in 2011–2012 in two valleys featuring exceptionally high densities of wild ungulates of up to 86 individuals per vegetation-covered square kilometre during summer and 28 individuals per vegetation-covered square kilometre during winter. Mean apical shoot loss ranged between 2.9% and 10.6% depending on study site and assessment year. In addition to the increasing sapling densities, these results suggest that ungulates had little impact on tree establishment in the studied subalpine conifer forests. Additionally, sapling diversity was higher on plots repeatedly influenced by ungulates (apical shoot loss), suggesting rather positive effects of ungulates on sapling diversity. Habitat containing a mixture of forest and grassland without livestock or human disturbance provides a high-quality environment for ungulates, which likely explains the low impact of ungulates on forest regeneration in our study area.

Spatial Patterns and Diversity of Alpine Vegetation across Langer-Shandur Valley, Hindukush Himalayas

While study of regional diversity and spatial distribution of species bears great relevance for conservation and management, Hindukush Himalayan (HKH) alpine zone lacks such information. The present study, through a rapid quantitative assessment of regional flora along Kukush Lake in Langar-Shandoor Valley, provides a better scientific understanding of diversity and distribution of alpine vegetation. Vegetation data were collected from eight sites using stratified random sampling. A total of 51 species (28 plant families) were recorded with an average species richness in the area of 2.14; Simpson's diversity, 0.75; evenness, 0.79 and average degree of community maturity index of 44%. Detrended correspondence analysis (DCA), regression analyses and factor analyses were used to identify vegetation associations. DCA clearly separated the associations along the first two axes. Altitude and moisture contents appeared to be key environmental factors governing the diversity and distribution of alpine vegetation. A negative correlation of altitude with diversity and richness was revealed. Vegetation exhibited significant variations in the diversity and distribution along the sampled sites. These variations may be attributed to the prevalent anthropogenic and livestock disturbances. The implications of the results have been discussed to highlight the conservation needs for protection of endemic floral elements in HKH alpine region.