Upslope Movement Research Articles

Evolution characteristic of soil water in loess slopes with different slope angles

BackgroundIn the Loess Plateau region, significant engineering activities have led to many exposed loess slopes. These slopes have undergone a series of shallow failures under rainfall, significantly affecting their stability. Vegetation can somewhat restore the ecological damage to the slope surfaces and enhance their stability. Thus, studying the spatiotemporal evolution of soil moisture migration under vegetation protection on loess slopes is crucial.MethodsEmploying experimental designs with slope gradients of 45° and 60°, this investigation is structured around a trio of core objectives: to delineate the processes of rainfall infiltration and its redistribution within the slope, to chart the evolution of soil water within the loess soil matrix, and to discern the impacts of slope inclination on soil water dynamics. Critical to this study are the monitoring of volumetric moisture content, matric suction, and the external variables of rainfall and temperature, alongside an analysis of soil water potential and moisture movement as observed in laboratory setups and simulated through Hydrus-2D.ResultsThe study revealed that slope angle significantly affects soil moisture infiltration and redistribution. The steeper slope (60°) exhibited more pronounced fluctuations in soil water potential, particularly during the rainy season, reflecting the dynamic nature of water movement. This slope also demonstrated sharper transitions in soil moisture during drying periods, indicating a greater sensitivity to weather changes. Water movement parallel to the slope surface was faster on steeper slopes, especially under drying conditions, with more pronounced lateral downslope flow at the surface layer. In contrast, the gentler slope (45°) showed more consistent moisture retention during wet periods, with slower and more uniform soil moisture movement, leading to a steadier moisture gradient and prolonged upslope movement. Vegetation plays a crucial role in modulating soil moisture dynamics, with grass growth being more effective on the steeper 60° slope. The extensive root network on this slope enhanced water retention, increased soil permeability, and reduced erosion. During the drying phase, deeper root systems significantly reduced volumetric water content at shallower depths, promoting higher moisture content in the middle sections of the slope.

Shifts in elevational distributions of montane birds in an arid ecosystem

Montane species are generally predicted to respond to climate change via upslope movement. Elevational range shifts of birds rarely have been examined in arid regions. Here, we examine shifts in the elevational distributions of breeding birds from two regions of the Great Basin, a desert in the western USA, over 10 to 20 years. We collected data annually from 2001 to 2020, a relatively long and consistent time series that is uncommon in research on distributional shifts. We used single‐species occupancy models of 32 bird species to examine shifts along the full elevational gradient (1650–3200 m a.s.l.) and within the lowest and highest edges (25%) of the gradient. We then conducted simulations to test whether population stochasticity could confound inferences about shifts. We examined whether temperature, precipitation, and primary productivity (normalized difference vegetation index) were associated with occupancy and shifts. The elevational distributions of 23 species shifted, and simulations indicated that shifts in the distributions of 18 species were unlikely to be stochastic. The majority of shifts in the western Great Basin were downslope, whereas those in the central Great Basin were upslope. More shifts occurred at the edges of the elevational gradient than along the full gradient. Elevational shifts lacked a consistent climate‐response signal, but those of some species appeared to follow changes in primary productivity. We found regional differences in elevational shifts and climate associations, and our work suggests that these desert bird populations may be relatively resilient to climate change.

Reciprocal transplants reveal asymmetric local adaptation of Himalayan Rhododendron approaching elevational range limit

AbstractAs plant species expand their upper limits of distribution under current warming, some retain both traditional climate space and biotic environment while others encounter novel conditions. The latter is the case for Rhododendron campanulatum, a woody shrub that grows both above and below treeline at our study site in the Eastern Himalayas where a very conspicuous, stable treeline was defined by a nearly contiguous canopy of tall Abies spectabilis trees, many of which are over a century old. Prior work showed that treeline had remained static in this region while R. campanulatum expanded its elevational range limit. We tested local adaptation of R. campanulatum by performing reciprocal transplants between the species' current elevational range limit (4023 m above sea level [asl]) and just above treeline (3876 m asl). Contrary to expectation, the coldest temperatures of late winter and early mid‐spring were experienced by plants at the lower elevation: R. campanulatum at species' limit (upper site) were covered by snow for a longer period (40 more days) and escaped the coldest temperatures suffered by conspecifics at treeline (lower site). The harsher spring conditions at treeline likely explain why leaves were smaller at treeline (15.3 cm2) than at species limit (21.3 cm2). Contrary to results from equivalent studies in other regions, survival was reduced more by downslope than by upslope movement, again potentially due to extreme cold temperatures observed at treeline in spring. Upslope transplantation had no effect on mortality, but mortality of species limit saplings transplanted downslope was three times higher than that of residents at both sites. A general expectation is that locals should survive better than foreign transplants, but survival of locals and immigrants at our species limit site was identical. However, those species limit saplings that survived the transplant to treeline grew faster than both locals at treeline and the transplants at species limit. Overall, we found asymmetric adaptation: Compared with treeline saplings, those at species limit (147 m above treeline) were more tolerant of extremes in the growing season but less tolerant of extremes in winter and early mid‐spring, displaying local adaptation in a more complex manner than simply home advantage, and complicating predictions about impacts of future regional climate change.

Wildfire facilitates upslope advance in a shade-intolerant but not a shade-tolerant conifer.

Wildfires may facilitate climate tracking of forest species moving upslope or north in latitude. For subalpine tree species, for which higher elevation habitat is limited, accelerated replacement by lower elevation montane tree species following fire may hasten extinction risk. We used a dataset of postfire tree regeneration spanning a broad geographic range to ask whether the fire facilitated upslope movement of montane tree species at the montane-to-subalpine ecotone. We sampled tree seedling occurrence in 248 plots across a fire severity gradient (unburned to >90% basal area mortality) and spanning ~500 km of latitude in Mediterranean-type subalpine forest in California, USA. We used logistic regression to quantify differences in postfire regeneration between resident subalpine species and the seedling-only range (interpreted as climate-induced range extension) of montane species. We tested our assumption of increasing climatic suitability for montane species in subalpine forest using the predicted difference in habitat suitability at study plots between 1990 and 2030. We found that postfire regeneration of resident subalpine species was uncorrelated or weakly positively correlated with fire severity. Regeneration of montane species, however, was roughly four times greater in unburned relative to burned subalpine forest. Although our overall results contrast with theoretical predictions of disturbance-facilitated range shifts, we found opposing postfire regeneration responses for montane species with distinct regeneration niches. Recruitment of shade-tolerant red fir declined with fire severity and recruitment of shade-intolerant Jeffrey pine increased with fire severity. Predicted climatic suitability increased by 5% for red fir and 34% for Jeffrey pine. Differing postfire responses in newly climatically available habitats indicate that wildfire disturbance may only facilitate range extensions for species whose preferred regeneration conditions align with increased light and/or other postfire landscape characteristics.

Elevational pattern, structure, and regeneration status of woody taxa along a semi-disturbed timberline ecotone in northwestern Himalayas

The composition, structure, and patterns of vegetation undergo a noticeable shift along the elevational gradient, and this is regulated by various abiotic variables, primarily the elevation and edaphic characteristics. The present study investigated the change in community characteristics of woody vegetation along a vertical gradient from 2800 m till 4000 m in parts of upper Bani Wildlife Sanctuary in Jammu and Kashmir. In all, 40 woody species were recorded including 11 trees and 29 shrubs with a distinctive hump shaped pattern that becomes steeper with the rising elevation. Quercus semecarpifolia Sm. and Betula utilis D.Don. exhibited a wide elevational range (3000–3500 m asl), eventually forming the climatic climax along southern and northern aspects. The diversity and phytosociological attributes peaked at intermediate elevation with H¯=1.74 recorded for trees and H¯=2.48 observed for shrubs. The average density and basal cover for trees and shrubs ranged between 75.50 Nha−1 & 20.09 m2ha−1 and 69.31 Nha−1 & 4.50 m2ha−1, respectively. The species turnover rate was recorded high in case of trees (0.11–0.77) and low for shrubs (0.17–0.29). A modest density of 114 seedlings ha−1 and 249 saplings ha−1 was recorded across the forest types. The low seedling (0.22) and sapling (0.48) per tree ratio indicated a low regeneration performance anticipating a very slow upslope movement of the tree line. This may result in population decline of a few select species in future, necessitating effective monitoring and management intervention for which these findings will be helpful.

A Biological‐Parameter‐Optimized Modeling Study of Physical Drivers Controlling Seasonal Chlorophyll Blooms off the Southern Coast of Java Island

AbstractA physical‐biogeochemical model consists of many key parameters; theoretically, 10,000 or more numerical experiments are required to obtain a set of optimal biological parameters. The corresponding computing resources are too expensive when running a three‐dimensional and high‐resolution physical‐biogeochemical model. In this study, we improve the performance of a three‐dimensional physical‐biogeochemical model via the conditional nonlinear optimal perturbation method for southern Java Island, where chlorophyll blooms occur seasonally. Based on the improved model results, we calculated the mixed‐layer nutrient budget, thereby characterizing how each physical process transports nutrients into the surface oligotrophic layer and then stimulates the chlorophyll blooms during the southeast monsoon season. Nutrients that upwell along the submarine slope are found in narrow regions along the coast and spread into most of the study area by local wind‐induced offshore transport. The contribution of nonlinearity (advection) is essential to modulating the upslope movement of nutrients off the coast. If local winds are neglected in the model, onshore transport induced by the pressure gradient force in the zonal direction (alongshore) and subsequent downwelling would be dominant, and chlorophyll blooms would diminish in most regions. The role of the South Java Coastal Current varies under the joint influence of remote and local wind forcings. The Indonesian Throughflow from the Lombok Strait also contributes to surface phytoplankton growth along its path off the south of Java Island.

Drivers of forest change in the Greater Yellowstone Ecosystem

AbstractQuestionsGlobal climate change is predicted to cause widespread shifts in the distribution and composition of forests, particularly in mountain environments where climate exerts strong controls on tree community arrangement. The upslope movement of vegetation has been observed in association with warming temperatures and is especially evident in ecotones—the transition zones between vegetation types. We explored the role of drought and tree mortality on recent changes in high‐elevation forests.LocationGreater Yellowstone Ecosystem, USA.MethodsWe established 19 forest demography plots along an elevational gradient spanning dominant high‐elevation vegetation types.ResultsTree establishment dates indicated the upslope movement of Pinus albicaulis (whitebark pine) treeline and ecotone shift from meadow to forest starting in the 1950s. An expansion of the growing season likely contributed to the upward expansion of the treeline. Comparisons between overstory and understory tree composition suggested ongoing succession in the absence of fire at lower elevations, namely the replacement of Pinus contorta (lodgepole pine) by Abies lasiocarpa (subalpine fir). P. contorta seedlings were distributed at higher elevations than overstory trees of the same species, suggesting some potential for upslope movement with warming conditions; P. albicaulis seedlings, conversely, were distributed throughout all elevations of the transect. Significant tree mortality occurred in Pinus spp. and disproportionately affected P. albicaulis, as a result of a regional Dendroctonus ponderosae (mountain pine beetle) outbreak (2008–2012). Mortality events were strongly associated with drier than average conditions 2–3 years prior to tree death.ConclusionRising sensitivity to arid conditions in the mid‐20th century amid already dense, aging forests appears to have increased susceptibility to beetle‐induced mortality during the most recent drought. Tree species in the study area responded individually to global change stressors, which acted on these forests in complex ways and led to both ecotone shifts and stability. This work highlights the interplay between succession, forest disturbances and climate‐related growth responses in driving forest compositional change in subalpine and treeline environments.

Fingerprints of Climate Change from the Indian Himalayan Environment: Need to Inculcate in Environment Education for Schools and Colleges

Himalayas are the youngest mountain range in the world that are experiencing the implications of climate change occurring at the local and regional levels. This does not only affect the ecologically diverse natural landscapes in the Himalayan region but also disrupts the natural habitats and distribution of species. The synthesis of the available literature indicates that abrupt changes in climate, especially at higher elevations are affecting the natural distribution of plant and animal taxa. The unpredictable movement of wildlife beyond their natural ranges underpin disturbances under micro climatic conditions and alteration of environmental niches. Though upslope movement of quite a few species has been observed, the extent to which these can be attributed to climate change is not clearly known. Considering the fingerprints of climate change in the Indian Himalaya, which has been considered as an ecological fragile landscape, there is a need to revisit and restructure our priorities for wildlife conservation. Moreover, monitoring species’ responses over time and documenting indigenous knowledge of local communities would strengthen our actions in addressing the impacts of climate change. Furthermore, by adding climate change education in the school system, considering it to be mandatory, can be remedied only by providing appropriate knowledge and through a structured training programme on climate change mitigation and adaptation process.

Are protected areas well-sited to support species in the future in a major climate refuge and corridor in the United States?

To help conserve biodiversity in coming decades, protected areas need to be located in places that will be important for species as their ranges shift to track suitable climatic conditions. Had past protected areas been optimally targeted to cover today's biodiversity, then we would expect future coverage to decline. However, past protected area siting was often biased towards higher elevations and, with upslope movements of many species predicted under climate change projections, perhaps future coverage may improve as a result. We examine present and future coverage of species potential ranges by protected areas in the Appalachian Mountains, a critical climate refuge and corridor for the biodiversity of the eastern United States. We parameterize climate niche models using the Maxent algorithm with occurrence records for 258 amphibian, bird, mammal, and reptile species of conservation policy concern that depend on forested habitat. We forecast future range shifts by integrating climate projections from six global circulation models and two representative concentration pathways while making contrasting assumptions about species dispersal. We then examine coverage of the estimated present and future ranges of species by existing protected areas. Most of these policy relevant species (93%) have less than 15% of their present estimated range in the region covered by protected areas. We found that species ranked as high conservation priority would be poorly protected under future climate scenarios. We predicted amphibian and mammal coverages by protected areas would worsen whereas coverages of birds and reptiles improve if species are able to disperse freely to future climatically suitable habitat. If species movements are more restricted, then we predict marked losses of species from protected areas, particularly amphibians and mammals. Our results identify obvious candidate locations for adding new protected areas in places that are currently under-protected and that harbor a high diversity of species across all future climate scenarios we consider.

Identifying Habitat Holdouts for High Elevation Tree Species Under Climate Change

High elevation tree species are at great risk of decline under climate change—particularly in ranges below tree line where upslope movement is not possible —as warmer temperatures reduce snowpack and increase evaporative demand. Forecasting future locations of persistence is key to the conservation of those species. In this study, we had two major objectives: 1) to determine the potential decline in the extent of three montane conifers in California, USA, and 2) to assess how model resolution affected our estimates of decline and whether this could inform identifying potential holdouts. To do so, we forecast forest dynamics, disturbances, and future distributions of three montane conifer species under a changing climate in the Klamath Mountains using the LANDIS-II forest simulation model. Simulations were run under two grain sizes, 0.81 ha and 7.29 ha cells, and four GCMs representing three relative concentration pathways. The area occupied by the three montane conifers declined by the end of the 21st century, with only a few areas where the species were able to persist. Higher levels of climate forcing resulted in greater declines. Moreover, higher temperatures reduced tree regeneration although adult populations persisted despite the climate disequilibrium. Model resolution but did not alter the overall trend of decline. These species were projected to remain in only a few limited areas by the end of the century, but because these species are widely dispersed on the larger landscape, managers must consider trade-offs between local and broader conservation efforts and consider the current and potential range of these conifers throughout the west.

Prediction of upslope movement of Rhododendron arboreum in Western Himalaya

Climate change poses significant challenges to distribution of plant species. Rhododendron arboreum is considered as a keystone species between subalpine and the alpine regions. In the present study, we predict its future distribution in the Indian part of Western Himalaya by employing two species distribution modelling techniques. We used five least correlated climate variables: mean diurnal temperature range, annual mean temperature, annual precipitation, precipitation of driest quarter and precipitation seasonality to predict the potential distribution of R. arboreum for the current condition. We subtracted the current distribution from projected maps of the Representative Concentration Pathways (RCP) 4.5 and RCP 6.0 scenarios for the year 2070 to quantify the magnitude and direction of range shift of the species in the future environment. Rhododendron arboreum is predicted to shift its distribution towards higher elevations more prominently in case of RCP 6.0. The species is likely to be influenced by annual precipitation for its distribution during current to future climate change scenarios. The study predicts upslope movement of R. arboreum in response to climate change impacts, where topography could play a significant role. Prediction of distribution pattern of R. arboreum highlights the need to take up future works focussing on development of a robust approach towards integrating genomic, environmental, climate and conservation information for predictive modelling of R. arboreum in its home range in the entire Indian Himalayas.

Tracer Transport within Abyssal Mixing Layers

AbstractMixing layers near sloped topography in the abyss are thought to play a critical role in the global overturning circulation. Yet the behavior of passive tracers within sloping boundary layer systems has received little attention, despite the extensive use of tracer observations to understand abyssal circulation. Here, we investigate the behavior of a passive tracer released near a sloping boundary within a flow governed by one-dimensional boundary layer theory. The spreading rate of the tracer across isopycnals is influenced by factors such as the bottom-intensification of mixing, the dipole of upwelling (in the boundary layer) and downwelling (in the outer mixing layer), and along-isopycnal diffusion. For isolated near-boundary tracer releases, the bulk diffusivity, proportional to the rate of increase of the variance of the tracer distribution in buoyancy space, is much less than what would be expected from averaging the diapycnal diffusivity over the tracer patch. This stems from the presence of the bottom boundary that prevents tracer diffusion through it. Furthermore, when along-isopycnal diffusion is weak, the boundary tends to drive the tracer up the slope toward less dense fluid on average due to asymmetries between boundary layer and interior flows. With strong along-isopycnal diffusion this upslope movement is reduced, while at the same time the average diapycnal spreading rate is increased due to a reduced influence of the bottom boundary. These results have implications for what can be learned about the characteristics of mixing near sloping boundaries from past and future tracer-release experiments.

Land-use change interacts with climate to determine elevational species redistribution

Climate change is driving global species redistribution with profound social and economic impacts. However, species movement is largely constrained by habitat availability and connectivity, of which the interaction effects with climate change remain largely unknown. Here we examine published data on 1464 elevational range shifts from 43 study sites to assess the confounding effect of land-use change on climate-driven species redistribution. We show that baseline forest cover and recent forest cover change are critical predictors in determining the magnitude of elevational range shifts. Forest loss positively interacts with baseline temperature conditions, such that forest loss in warmer regions tends to accelerate species’ upslope movement. Consequently, not only climate but also habitat loss stressors and, importantly, their synergistic effects matter in forecasting species elevational redistribution, especially in the tropics where both stressors will increase the risk of net lowland biotic attrition.

Tracers Reveal Recharge Elevations, Groundwater Flow Paths and Travel Times on Mount Shasta, California

Mount Shasta (4322 m) is famous for its spring water. Water for municipal, domestic and industrial use is obtained from local springs and wells, fed by annual snow melt and sustained perennially by the groundwater flow system. We examined geochemical and isotopic tracers in samples from wells and springs on Mount Shasta, at the headwaters of the Sacramento River, in order to better understand the hydrologic system. The topographic relief in the study area imparts robust signatures of recharge elevation to both stable isotopes of the water molecule (δ18O and δD) and to dissolved noble gases, offering tools to identify recharge areas and delineate groundwater flow paths. Recharge elevations determined using stable isotopes and noble gas recharge temperatures are in close agreement and indicate that most snowmelt infiltrates at elevations between 2000 m and 2900 m, which coincides with areas of thin soils and barren land cover. Large springs in Mt Shasta City discharge at an elevation more than 1600 m lower. High elevation springs (>2000 m) yield very young water (<2 years) while lower elevation wells (1000–1500 m) produce water with a residence time ranging from 6 years to over 60 years, based on observed tritium activities. Upslope movement of the tree line in the identified recharge elevation range due to a warming climate is likely to decrease infiltration and recharge, which will decrease spring discharge and production at wells, albeit with a time lag dependent upon the length of groundwater flow paths.

Impacts of late Quaternary environmental change on the long-tailed ground squirrel (Urocitellus undulatus) in Mongolia.

Impacts of Quaternary environmental changes on mammal faunas of central Asia remain poorly understood due to a lack of comprehensive phylogeographic sampling for most species. To help address this knowledge gap, we conducted the most extensive molecular analysis to date of the long-tailed ground squirrel (Urocitellus undulatus Pallas 1778) in Mongolia, a country that comprises the southern core of this species’ range. Drawing on material from recent collaborative field expeditions, we genotyped 128 individuals at two mitochondrial genes (cytochrome b and cytochrome oxidase I; 1 797 bp total). Phylogenetic inference supports the existence of two deeply divergent infraspecific lineages (corresponding to subspecies U. u. undulatus and U. u. eversmanni), a result in agreement with previous molecular investigations but discordant with patterns of range-wide craniometric and external phenotypic variation. In the widespread western eversmanni lineage, we recovered geographically-associated clades from the: (a) Khangai, (b) Mongolian Altai, and (c) Govi Altai mountain ranges. Phylogeographic structure in U. u. eversmanni is consistent with an isolation-by- distance model; however, genetic distances are significantly lower than among subspecies, and intra-clade relationships are largely unresolved. The latter patterns, as well as the relatively higher nucleotide polymorphism of populations from the Great Lakes Depression of northwestern Mongolia, suggest a history of range shifts into these lowland areas in response to Pleistocene glaciation and environmental change, followed by upslope movements and mitochondrial lineage sorting with Holocene aridification. Our study illuminates possible historical mechanisms responsible for U. undulatus genetic structure and contributes to a framework for ongoing exploration of mammalian response to past and present climate change in central Asia.

Postbreeding elevational movements of western songbirds in Northern California and Southern Oregon

Migratory species employ a variety of strategies to meet energetic demands of postbreeding molt. As such, at least a few species of western Neotropical migrants are known to undergo short‐distance upslope movements to locations where adults molt body and flight feathers (altitudinal molt migration). Given inherent difficulties in measuring subtle movements of birds occurring in western mountains, we believe that altitudinal molt migration may be a common yet poorly documented phenomenon. To examine prevalence of altitudinal molt migration, we used 29 years of bird capture data in a series of linear mixed‐effect models for nine commonly captured species that breed in northern California and southern Oregon. Candidate models were formulated a priori to examine whether elevation and distance from the coast can be used to predict abundance of breeding and molting birds. Our results suggest that long‐distance migrants such as Orange‐crowned Warbler (Oreothlypis celata) moved higher in elevation and Audubon's Warbler (Setophaga coronata) moved farther inland to molt after breeding. Conversely, for resident and short‐distance migrants, we found evidence that birds either remained on the breeding grounds until they finished molting, such as Song Sparrow (Melospiza melodia) or made small downslope movements, such as American Robin (Turdus migratorius). We conclude that altitudinal molt migration may be a common, variable, and complex behavior among western songbird communities and is related to other aspects of a species’ natural history, such as migratory strategy.

Habitat requirements and population estimate of the endangered Ecuadorian TapaculoScytalopus robbinsi

SummaryThe Chocó-Tumbesian region of western Ecuador is one of the 25 global biodiversity hotspots harbouring high numbers of endemic species, which are heavily threatened by habitat loss and fragmentation. Moreover, ongoing climate change in the tropics drives species uphill as lower-lying areas are becoming constantly drier. Such upslope movement can pose major challenges for less mobile species, such as understorey birds which are confined to mature forests and unable to cross habitat gaps. Consequently, these species are threatened by a combination of upslope range shifts and forest fragmentation. In our study, we investigated population numbers and habitat requirements of the Ecuadorian TapaculoScytalopus robbinsi, which is endemic to the premontane cloud forests of south-western Ecuador. Comparing the microhabitat structure within territories with control sites revealed that Ecuadorian Tapaculos prefer old secondary forests. Moreover, connectivity between forest fragments was the strongest predictor of the presence of territories within them. We estimated the mean upslope shift of the distribution range as 100 m per decade and developed a model of habitat availability for the revised range. Extrapolating the number of territories from the study area to the distributional range of the Ecuadorian Tapaculo showed that the global population size is smaller than previously assumed. Our results suggest that the Ecuadorian Tapaculo is strongly affected by forest loss and degradation. Therefore, to prevent a continuing decline in population numbers or even extinction, conservation measures focusing on restoring connectivity between fragments and increasing habitat quality and quantity for the remaining populations need to be prioritised.

Livestock tracks transform resource distribution on terracette landscapes of the Loess Plateau

AbstractStriking networks of livestock tracks, or terracettes, molded to the contours are a common feature on hilly rangelands of the semiarid Loess Plateau, one of the regions with the most severe soil erosion in the world. The formation of livestock tracks results in modified micro‐topography and ecological processes and leads to strong patterns in spatial distribution of vegetation, water, and nutrients. We investigated the spatial pattern of the topo‐edaphic, hydrological, biogeochemical, and biological attributes of these terracette landscapes and explored their potential implications to ecosystem functions. The results showed strong spatial heterogeneity in topo‐edaphic and biological structure of these landscapes, organized with three segments of a basic landscape unit—track, shoulder, and interslope. The above‐ and below‐ground biomass and soil nutrients concentrated in the shoulder segment forming a “band of fertility”. The network of livestock tracks likely reduced surface runoff and erosion by intercepting runoff and facilitate infiltration, while posing little risk of increasing shallow slope failures given the structure of loess soil. There appears a positive feedback loop for maintaining the structure of terracette landscapes. Trampling by goats maintains the tracks, which leads to spatial heterogeneity in biophysical structure and processes. The network of tracks enabled the goats to travel and graze in ways that reduce energy expenditure and increase foraging efficiency, which leads to strongly preferential use of the tracks by the goats. There are also evidence of a possible process resemble a slope parallel retreat at a micro‐scale, which may result in upslope movement of the terracettes. There may be important functional differences between landscapes with and without networks of livestock tracks, in regulating water runoff and soil erosion, forage production, and soil carbon storage. These functional differences may have significant implications to land use policies and practices aiming at soil and water conservation and socioecological sustainability of the Loess Plateau.

Alpine treeline and timberline dynamics during the Holocene in the Northern Romanian Carpathians

High altitude environments (treeline and alpine communities) are particularly sensitive to climate changes, disturbances and land-use changes due to their limited tolerance and adaptability range, habitat fragmentation and habitat restriction. The current and future climate warming is anticipated to shift the tree- and timberlines upwards thus affecting alpine plant communities and causing land-cover change and fragmentation of alpine habitats. An upslope movement of some trees, shrubs and cold adapted alpine herbs as a response to the current climate warming has already been noted in many montane and subalpine regions. Four Holocene peat and lacustrine sediment sequences located between 1670 and 1918 m a.s.l. (Fig.1), in the Rodna Mountains (Northern Romania, Eastern Carpathians) are used with the aim to determine: i) the sensitivity of high mountain habitats to climate, fire and land use changes; ii) tree- and timberline shifts: and iii) the influence of landscape topography on trees and shrubs.

Management, winter climate and plant–soil feedbacks on ski slopes: a synthesis

AbstractOwing to the increasing popularity of skiing and the upslope movement of the snow reliability line in mountain regions, more and more alpine environments are being turned into skiing areas, with strong impacts on ecosystem functions and biodiversity. Creation and management of ski slopes cause physical disturbance to soil and vegetation, while (artificial) snow supplements affect soil structure, chemistry, moisture and temperature regimes as well as shifts in snow season and growing season length. Vegetation–soil feedbacks may influence the outcome of these interactive effects on soil and vegetation, with possible consequences for soil erosion. Moreover, climate warming will lead to changing snow cover and duration, which will interact with ski slope management effects on soil and vegetation and its feedbacks. Based on a conceptual framework we review the main elements of these interactive effects on soil and vegetation on new and established ski slopes. We also set a research agenda with specific studies that could further advance our understanding of interacting ski slope management, winter climate, vegetation–soil feedbacks and ecosystem functioning. In such new investigations, alpine climate change ecology can probably learn much from the “experimental” disturbance and snow manipulations on ski slopes and vice versa.