High Elevation Research Articles

Evaluating Distributed Snow Model Resolution and Meteorology Parameterizations Against Streamflow Observations: Finer Is Not Always Better

AbstractEstimating snow conditions is often done using numerical snowpack evolution models at spatial resolutions of 500 m and greater; however, snow depth in complex terrain often varies on sub‐meter scales. This study investigated how the spatial distribution of simulated snow conditions varied across seven model spatial resolutions from 30 to 1,000 m and over two meteorological data sets, coarser (≈12 km) and finer (4 km). Simulated snow covered area (SCA) was compared to remotely sensed SCA and simulated watershed mean peak snow water equivalent (SWE) was compared to four streamflow statistics representing different water management‐relevant aspects of the hydrograph using non‐parametric correlations. April 1 SWE tended to increase with model resolution, particularly below 4,000 masl. Finer meteorology simulations produced deeper April 1 SWE than coarser meteorology simulations. Finer resolution snow simulations tended to produce longer snowmelt durations and slower snowmelt rates than coarser resolution simulations. Finer resolution simulations had better agreement with SCA for both meteorology data sets, particularly at high and low elevations. However, finer resolution simulations did not generally outperform coarser simulations in snow versus streamflow statistic correlations. Snow versus streamflow correlations were most sensitive to meteorology, watershed properties, and then resolution. Watershed physiographic properties such as wetness index may increase snow versus streamflow metric correlations while elevation and slope may decrease correlations. At watershed scales, these results suggest that simulation resolution and choice of meteorology is less important than the physiographic properties of the watershed; however, if resolving snow distribution across the landscape is important, finer‐resolution simulations are useful.

Insufficient and biased representation of species geographic responses to climate change.

The geographic redistributions of species due to a rapidly changing climate are poised to perturb ecological communities and significantly impact ecosystems and human livelihoods. Effectively managing these biological impacts requires a thorough understanding of the patterns and processes of species geographic range shifts. While substantial recent redistributions have been identified and recognized to vary by taxon, region, and range geometry, there are large gaps and biases in the available evidence. Here, we use the largest compilation of geographic range change observations to date, comprised of 33,016 potential redistributions across 12,009 species, to formally assess within- and cross-species coverage and biases and to motivate future data collection. We find that species coverage varies strongly by taxon and underrepresents species at high and low latitudes. Within species, assessments of potential redistributions came from parts of their geographic range that were highly uneven and non-representative. For most species and taxa, studies were strongly biased toward the colder parts of species' distributions and thus significantly underrepresented populations that might get pushed beyond their maximum temperature limits. Coverage of potential leading and trailing geographic range edges under a changing climate was similarly uneven. Only 8% of studied species were assessed at both high and low latitude and elevation range edges, with most only covered at one edge. This suggests that substantial within-species biases exacerbate the considerable geographic and taxonomic among-species unevenness in evidence. Our results open the door for a more quantitative accounting for existing knowledge biases in climate change ecology and a more informed management and conservation. Our findings offer guidance for future data collection that better addresses information gaps and provides a more effective foundation for managing the biological impacts of climate change.

The axial biomechanics of Trigonosaurus pricei (Neosauropoda: Titanosauria) and the importance of the cervical–dorsal region to sauropod high-browser feeding strategy

Abstract Trigonosaurus pricei is a small to medium-sized sauropod dinosaur (Sauropoda: Titanosauria) from the Late Cretaceous Bauru Group of Brazil that is known from a significant amount of recovered axial elements [four cervical vertebrae, 10 dorsal vertebrae, sacrum (MCT 1488-R), and 10 caudal vertebrae (MCT 1719-R)]. In this biomechanical work, we approach the hypothesis of the cartilaginous neutral pose and the range of motion of the axial series of Trigonosaurus. The results show that this sauropod could be capable of high elevation of the neck resulting from morphological adaptations of the cervicodorsal region on dorsal (D) vertebrae D2 and D3 (e.g. postzygapophyses of D2 positioned over the vertebral centrum and prezygapophyses of D3 over the anterior vertebral centrum). This implies that D2 articulates (cartilaginous neutral posture) with D3 only at a strong dorsally directed angle, resulting in a shift in the direction of the neck to a more elevated posture. Furthermore, the tail attributed to Trigonosaurus as a paratype could be oriented in the horizontal ‘direction’ and presented a sigmoidal ‘shape’. This work contributes generally to the understanding of variation in the body plan of sauropods and, more specifically, to the feeding strategy of small and medium-sized titanosaurs from semi-arid regions of Gondwana.

New High Elevation Records for the Mesic Four-Striped Grass Rat Rhabdomys dilectus on Mount Kilimanjaro, Tanzania

New High Elevation Records for the Mesic Four-Striped Grass Rat Rhabdomys dilectus on Mount Kilimanjaro, Tanzania

PENANGANAN BANJIR DAERAH ALIRAN SUNGAI BABON KOTA SEMARANG

Floods are natural disasters that we often encounter during the rainy season. Apart from there are also tidal floods which are caused by global warming, this problem occurs in the city of Semarang, especially North Semarang, specifically the north coast of the Java Sea. Floods that occurred in 2021 in the city of Semarang include Starting from Genuk, Kaligawe, Satsiun Tawang, Tanjungmas, Karangayu, the flood disaster was caused by high rainfall, while tidal floods caused high tides and inundated roads and houses of residents on the north coast of Semarang city. To handle this problem, the government Currently we have made embankments, namely making embankments including the Sringin River which is equipped with a ponpa, Tenggang River, Babon River, Semarang River, Banger River, and others. These embankments are equipped with pumps so that when the water from upstream to downstream is high, the water is pumped. to the sea, the aim is to find out one of the annual discharges of the river, namely the Babon, and to find out the tamping capacity of the Babon River Longstorage. Apart from that, there is a method for handling tidal floods, namely using the Babon River Longstorage which is equipped with a pump, if there is high tide which inundates roads and houses. residents then the pump is turned on, whereas if the water recedes and does not inundate residential areas then the pump is turned off. Flood control analysis is calculated using the HEC-RAS program simulation using a return period of 50 years. Based on calculations using the HEC-HMS program. The flood discharge is 2,529 m3/sec. The high tide elevation is + 1.67 m, while the normal water level is -0.5 m.

Effects of Human Harvesting, Residences, and Forage Abundance on Deer Spatial Distribution.

It has been known that harvesting by humans strongly influences individual within-home range habitat selection of many deer species; however, little is known about the effect of harvesting on coarse-scale habitat selection (i.e., spatial distribution). We examined the summer spatial distribution of sika deer Cervus nippon in relation to human harvesting and other factors, such as human residences, forage abundance, and cover, using pellet group counts at Mount Fuji, central Japan, in 2018. In the study area, harvesting is conducted at medium elevation areas throughout the year, but not at high or low elevation areas where access is difficult or harvesting is prohibited. Spatial distribution of deer was significantly biased to non-harvesting areas and far from residential areas, suggesting that they avoid riskier spaces by establishing a landscape of fear. High-quality food resources (deciduous broad-leaved trees and forbs) were more abundant in harvesting areas than in non-harvesting areas, suggesting that foraging pressure by deer reduce them. However, there were no differences in abundances of more fibrous dwarf bamboo between harvesting and non-harvesting areas, and spatial distribution of deer was significantly biased to higher dwarf bamboo abundance areas, suggesting that the dwarf bamboo is an alternative food resource in non-harvesting areas where supplies of high-quality food were limited. Our results suggest that human harvesting pressure and residences shifted the spatial distribution of deer from the montane forests to subalpine/alpine zones, which may increase damage to vulnerable ecosystems due to severe foraging pressure.

Effects of climate change on plant-pollinator interactions and its multitrophic consequences

AbstractThere is wide consensus that climate change will seriously impact flowering plants and their pollinators. Shifts in flowering phenology and insect emergence as well as changes in the functional traits involved can cause alterations in plant-pollinator interactions, pollination success and plant reproductive output. Effects of rising temperatures, advanced snowmelt and altered precipitation patterns are expected to be particularly severe in alpine habitats due to the constrained season and upper range margins. Yet, our understanding of the magnitude and consequences of such changes in life history events and functional diversity in high elevation environments is incomplete.This special issue collects novel insights into the effects of climate change on plant-pollinator interactions in individual plant species and on network structure of entire plant and pollinator communities in alpine ecosystems. Using simulated changes of earlier snowmelt, natural gradients of variation in temperature, precipitation and snowmelt, or a long-term monitoring approach, these studies illustrate how plant species, plant communities, and pollinators respond to variation in environmental conditions associated with scenarios of ongoing climate change.The collection of papers presented here clearly demonstrates how spatial or temporal variation in the environmental climatic context affects flower abundances and plant community composition, and the consequences of these changes for pollinator visitation, pollination network structure, pollen transfer dynamics, or seed production. As changes in the availability of flowers, fruits, and seeds are likely to impact on other trophic levels, the time is ripe and pressing for a holistic multitrophic view of the effects of climate change on biotic interactions in alpine ecological communities.

Groundwater seeps are hot spots of denitrification and N2O emissions in a restored wetland

Restorations of former cranberry farms (“bogs”) aim to re-establish native wetland vegetation, promote cold water habitat, and attenuate nitrogen (N) delivery to coastal waters. It is unclear, though, how elements of restoration design such as microtopography, groundwater interception, and plant communities affect N removal via denitrification. In a recently restored riparian cranberry bog with created microtopography, we compared denitrification potential, nitrous oxide (N2O) yield of denitrification (ratio of N2O:N2O + N2 gases), in situ N2O fluxes, soil chemistry, and plant communities at the highest and lowest elevations within 20 plots and at four side-channel groundwater seeps. Denitrification potential was > 2 × greater at low elevations, which had plant communities distinct from high elevations, and was positively correlated with plant species richness (Spearman’s rho = 0.43). Despite detecting high N2O yield (0.86 ± 0.16) from low elevation soils, we observed small N2O emissions in situ, suggesting minimal incomplete denitrification even in saturated depressions. Groundwater seeps had an order of magnitude higher denitrification potentials and 100–300 × greater soil NO3− concentrations than the typically saturated low elevation soils. Groundwater seeps also had high N2O yield (1.05 ± 0.15) and higher, but spatially variable, in situ N2O emissions. Our results indicate that N removal is concentrated where soils interact with NO3–rich groundwater, but other factors such as low soil carbon (C) also limit denitrification. Designing restoration features to increase groundwater residence time, particularly in low lying, species rich areas, may promote more N attenuation in restored cranberry bogs and other herbaceous riparian wetlands.

The deglacial history of 79N glacier and the Northeast Greenland Ice Stream

The Northeast Greenland Ice Stream (NEGIS) is the main artery for ice discharge from the northeast sector of the Greenland Ice Sheet (GrIS) to the North Atlantic. Understanding the past, present and future stability of the NEGIS with respect to atmospheric and oceanic forcing is of global importance as it drains around 17% of the GrIS and has a sea-level equivalent of 1.6 m. This paper reconstructs the deglacial and Holocene history of Nioghalvfjerdsbræ (or 79N Glacier); a major outlet of the NEGIS.At high elevation (>900 m asl) autochthonous blockfield, a lack of glacially moulded bedrock and pre LGM exposure ages point to a complex exposure/burial history extending back over half a million years. However, post Marine Isotope Stage 12, enhanced glacial erosion led to fjord incision and plateaux abandonment. Between 900 and 600 m asl the terrain is largely unmodified by glacial scour but post LGM erratics indicate the advection of cold-based ice through the fjord. In contrast, below ∼600 m asl Nioghalvfjerdsfjorden exhibits a geomorphological signal indicative of a warm-based ice stream operating during the last glacial cycle. Dated ice marginal landforms and terrain along the fjord walls show initial thinning rates were slow between ∼23 and 10 ka, but post-10 ka it is evident that Nioghalvfjerdsfjorden deglaciated extremely quickly with complete fjord deglaciation below ∼500 m asl between 10.0 and 8.5 ka.Both increasing air and ocean temperatures were pivotal in driving surface lowering and submarine melt during deglaciation, but the final withdrawal of ice through Nioghalvfjerdsfjorden was facilitated by the action of marine ice sheet instability. Our estimates show that thinning and retreat rates reached a maximum of 5.29 ma−1 and 613 ma−1, respectively, as the ice margin withdrew westwards. This would place the Early Holocene disintegration of this outlet of the NEGIS at the upper bounds of contemporary thinning and retreat rates seen both in Greenland and Antarctica. Combined with recent evidence of ice stream shutdown during the Holocene, as well as predictions of changing ice flow dynamics within downstream sections of the NEGIS catchment, this suggests that significant re-organisation of the terminal zone of the ice stream is imminent over the next century.

Carbon Reduction Associated with Sediment Reworking through Burrows of the Thalassinid Mud Shrimp Laomedia sp. (Crustacea: Laomediidae) from Korean Intertidal Sediments

This study evaluated the biotic and abiotic factors influencing the sediment reworking rate (SRR) of Laomedia sp. through in situ measurements and assessed the organic carbon reduction by comparing carbon concentrations between particles collected from the water column and reworked sediments. The SRR was significantly correlated with the duration of submergence at high elevation, whereas it showed a stronger correlation with mound height than with the duration of submergence at low elevation. The organic carbon content of suspended particles was reduced by 68% by the sediment reworking of Laomedia sp., with a mean organic carbon reduction of 0.01 gC ind.−1 d−1. This reduction resulted from particle selection by the inhabitant and by accumulation along the burrow walls. The estimated annual organic carbon reduction associated with the sediment reworking was 12.8 gC m−2 yr−1. The transport of organic carbon from the burrows into the water column was comparatively high relative to other species. These findings suggest that Laomedia sp. plays a significant role in enhancing the carbon cycle as an important bioturbator, with its burrows acting as carbon sinks by trapping organic carbon in intertidal sediments. Therefore, bioturbation by macroinvertebrates should be considered when evaluating carbon sequestration in intertidal sediments.

Exploring the impact of surface lapse rate change scenarios on mountain permafrost distribution in four dissimilar valleys in Yukon, Canada

A scenario-based approach was used to test air and ground response to warming with and without changes to inverted surface lapse rates in four Yukon valleys. Generally, climate warming coupled with weakening of temperature inversions resulted in the greatest increase in air temperature at low elevations. However, ground temperatures at high elevations showed the greatest response to warming and variability between scenarios due to increased connectivity between air and ground. Low elevations showed less of a response to warming and permafrost was largely preserved in these locations. Local models also predicted higher permafrost occurrence compared to a regional permafrost probability model, due to the inclusion of differential surface and thermal offsets. Results show that the spatial warming patterns in these mountains may not follow those predicted in other mountain environments following elevation dependent warming (EDW). As a result, the concept of EDW should be expanded to become more inclusive of a wider range of possible spatial warming distributions. The purpose of this paper is not to provide exact estimations of warming, but rather to provide hypothetical spatial warming patterns, based on logical predictions of changes to temperature inversion strength, which may not directly follow the distribution projected through EDW.

Elevation Regulates the Response of Climate Heterogeneity to Climate Change

AbstractClimate change represents a profound threat to the diversity and stability of global climate zones. However, the complex interplay between climate change and elevation in shaping climate heterogeneity is not yet fully understood. Here, we combine Shannon's diversity index (SHDI) with the Köppen‐Geiger climate classification to explore the altitudinal distributions of global climate heterogeneity; and their responses to climate change. The study reveals a distinctive pattern: SHDI, a proxy for climate heterogeneity tends to slow down or decline at lower elevations with increasing temperatures, while at higher elevations, it continues to rise due to continuing cold conditions. Examination of climate simulations, both with and without anthropogenic forcing, confirms that observed changes in climate heterogeneity are primarily attributable to anthropogenic climate change within these high‐elevation regions. This study underscores the importance of high‐elevation regions as not only custodians of diverse climate types but also potential refuges for species fleeing warmer climates.

Elevation map-based variable rate poultry litter application is a promising method in cotton production

Variable rate poultry litter (PL) application can potentially increase cotton yield and reduce environmental degradation risks associated with excess applications. The objective of this study was to determine whether applying PL in an inherently variable cotton field as variable-rate based on soil organic matter (SOM, VRo) or elevation (VRe) maps leads to greater yield and production efficiency than applying by the traditional uniform rate (UR). Poultry litter was applied by varying the rate within ±20 % of the target rates (7.9–11.2 Mg ha−1) where the highest elevation or lowest SOM regions received the highest rate, and the lowest elevation or highest SOM regions received the lowest rate. A treatment fertilized with conventional synthetic fertilizers served as the standard control (Std). Cotton fertilized with PL, regardless of the application method, provided greater K, S, and P nutrition and increased lint yield by as much as 30 % relative to the Std treatment. Applying the PL by the VRe method increased the production efficiency (yield per unit applied PL) by nearly 13 % over the UR. The VRo treatment resulted in a yield reduction of up to 11.8 % but the production efficiency was 14.2 % greater than the UR treatment. Variable rate application based on SOM was not as effective as that based on elevation. The results overall show that PL was superior to synthetic fertilizers in this soil and this superiority could further be enhanced by applying the PL as variable rate based on elevation maps.

Exploring high intertidal refugia as an approach for the restoration of an intertidal oyster

Marine organisms frequently inhabit intertidal zones that serve as refuges from predation and competition but are not optimal physiologically. Restoration practitioners working with intertidal species may similarly have to consider whether restoration success will be greater where conditions are more benign (usually lower in the intertidal) or where negative biotic interactions are reduced (usually higher in the intertidal). In cases where a target species has greater desiccation tolerance than its enemies, restoration may be more successful higher in the intertidal zone, despite potential performance trade-offs. In many US West Coast estuaries, non-native drill species can decimate native oyster populations, posing a challenge to restoration. Given that native Olympia oysters Ostrea lurida should be better able to withstand tidal emersion than the non-native Atlantic oyster drill Urosalpinx cinerea, we explored using the high intertidal as a refuge from predation as a potential restoration technique. Using surveys and a field experiment, we investigated the recruitment, growth, and survival of oysters as well as drill abundance and predation over 3 tidal elevations. Oysters recruited and survived equally well at +0.1, +0.5, and +0.8 m mean lower low water, but juvenile oyster growth decreased with increasing elevation. In our experiment, predation on oysters was lower at the highest elevation than at low and mid elevations, but in natural populations there was a near complete absence of O. lurida at any elevation where U. cinerea was present. This suggests that a higher tidal elevation refuge is not a viable approach for oyster restoration in our study area.

What controls structural variations along the Zagros Collision Zone? Insights from geophysical observations and thermo-mechanical modelling

The Zagros Collision Zone is a complex tectonic region formed as a consequence of the collision between Arabia and Eurasia after the subduction of the Neo-Tethys ocean. The NW-SE striking Zagros orogen consists of the following parallel tectonic units (from SW to NE): Zagros Fold and Thrust Belt (ZFTB), Sanandaj–Sirjan Metamorphic Zone (SSZ), and Urumieh–Dokhtar Magmatic Arc (UDMA). In this study, we perform a combined analysis of recent geophysical data, revealing pronounced differences in the crustal and lithospheric structure along the Zagros Mountains. The northwestern sector shows a fairly uniform crustal thickening across the broad symmetric orogen from the ZFTB to the UDMA. In contrast, in the central Zagros, the transition from a relatively narrow zone of high elevations and high-frequency relief in the ZFTB to a smoother surface topography of the SSZ and UDMA occurs with an abrupt increase in Moho depth below the SSZ. The last observation has recently been interpreted as a result of “relamination” process, where the felsic upper crust of the Arabian plate underthrust the mafic crust of the Iranian plate. We present geodynamic numerical models of crustal relamination during continental collision and compute static gravity field of the resulting structures. We show that oblique closure of the Neo-Tethys affects lateral variations in the style and extent of crustal relamination, which control the observed along-strike changes in crustal configuration and orogen altitude. In particular, a narrow and higher orogen (as in the central Zagros) develops in the experiments with a young and wide oceanic plate, whereas an old and narrow subducting plate tends to form a broad and lower topography (as in the northwestern Zagros). This is geometrically consistent with the progressive closure of the Neo-Tethys from NW to SE during the oblique continental collision between Arabia and Eurasia.

Determination of Mountain Equivalent Rainstorm (MER) in Qinba Maintain Area Based on TRMM

The study of extreme precipitation is a significant aspect for investigating rainstorms, flash floods, and unpredictable disasters. Qinba mountain, Shaanxi province, China, is sensitive to extreme climate and rainstorm events. It is crucial to investigate the feature of precipitation extremes in this region with satellite data. According to this, the paper using the 1Day extreme precipitation datasets of TRMM and rain-gauge to calculate the mountain rainstorm, then the statistical metrics (CC, MBE, RMSE) was used in validation as the performance measure. The 1Day, 3Day, 5Day, and 7Day extreme precipitation was identified by the 95<sup>th</sup> percentile method. Thus to determine the Mountain Equivalent Rainstorm (MER). As the results, (1) Based on the comparison, the TRMM satellite product can capture the extreme precipitation mostly at the station below 433m (R<sup>2 </sup>>0.5) for 5Day datasets, while 7Day datasets reveal contrast patterns. (2) By applying the MER concept, the TRMM-based and gauge-based ratio revealed a similar pattern of mountain rainstorms at higher elevations and slightly different in the middle region. The mountain rainstorm amount was double the extreme rainfall at a higher elevation. Therefore, the defined extreme precipitation characteristics can assist the disaster risk reduction and mitigation strategy in the Qinba mountain of Shaanxi Province, China, and also provide a reference for improving the satellite algorithm in extreme precipitation measurement.

Analysis of Drivers’ Workload States on Highways in High Elevation Regions

The low-pressure (and low-oxygen) environment in plateau regions affects drivers’ psychophysiological states and, thus, driving behavior and road safety. Six scenarios of expressway exit ramps were constructed based on the UC/win-road simulator to quantitatively analyze the effect of the plateau environment on workload state. A total of 50 participants in Nanjing (altitude 50 m) and 50 participants in Lhasa (altitude 3,650 m) were recruited for the simulation experiments. Based on the principal component analysis, a sample entropy index (SEI) was constructed to reflect the drivers’ psychophysiological levels by combining the sample entropy of electroencephalogram (EEG) signals β%, β/(α+θ), β/α, and heart rate (HR). Meanwhile, the pupil area change rate and the percentage of fixation time and duration within the region of interest were analyzed to characterize the drivers’ visual workload. Based on the psychophysiological and visual load, the differences in workload states among plain and plateau drivers were analyzed using a regression model and a one-way analysis of variance (ANOVA) test. At the same time, the changing trends of the drivers’ workload states in the curved section of the exit ramp under different scenarios were analyzed. The plateau drivers experienced a higher level of mental stress and greater psychological load. Furthermore, the higher radius of horizontal curves reduced the visual load level for drivers when traveling on the highway exit ramp sections. These findings should serve as a valuable reference for refining the design of plateau expressway exit ramps and providing a theoretical basis for improving driving safety in plateau areas.

Landscape Ecological Risk and Drivers of Land-Use Transition under the Perspective of Differences in Topographic Gradient

Human activities have caused different degrees of land-use change on different topographic gradients, with impacts on the landscape and ecosystem. Effectively preventing and addressing ecological risk (ER) and achieving harmonious coexistence between humans and nature are important aspects of sustainable development. In this study, we used Gansu Province as an example, adopted five periods of land-use data in 1980, 1990, 2000, 2010 and 2020, and used the geoinformatic Tupu method and the terrain distribution index to study land-use changes under different topographic gradients, and then constructed the landscape ecological risk assessment (LERA) model based on the landscape pattern index to analyze landscape ecological risk (LER) spatiotemporal changes under different topographic gradients, and finally explored the LER driving factors using the geodetector model. The results showed that (1) the dominant land-use types were unused land and grassland, accounting for approximately 74% of the land. The situation of transferring and changing each type was more drastic. The distribution and changes in cropland and built-up land were easily found in low topographic gradient areas with low elevations and small slopes; the distribution and changes in woodland, grassland and water areas were easily found in high topographic gradient areas with high elevations and large slopes. (2) The landscape ecological risk index (LERI) was 0.018, 0.019, 0.019, 0.019 and 0.020, respectively, with spatial expressions of high in the northwest and low in the southeast. Low LER was concentrated in high topographic gradient ecological reserves; high LER was concentrated in low topographic gradient human interference areas and high topographic gradient natural environmental complex areas. (3) Natural factors mainly acted on the LER on moderate and high topographic position gradients; socioeconomic factors mainly acted on the LER on low topographic position gradients. Human interference interacted with natural factors more than human interference alone on LER. This study can provide a scientific basis for ensuring ecological security and sustainable development in areas with complex topography and geomorphology.

Siberian Pine and Larch Response to Warming-Drying Climate in the Southern Boundary of Their Range

Trees’ growth and areal responses to changing climate are primarily expected within the edges of the species range. Here, we compared the responses of Siberian pine (Pinus sibirica Du Tour), a moisture-sensitive species, and drought-resistant larch (Larix sibirica Ledeb.) at the southern part of their ranges in the Siberian Mountains (the Tannu-Ola Ridge). We study the species’ growth and proportion in the forests from forest-steppe to treeline ecotone along the elevation gradient. These studies are based on radial growth index (GI) analysis and GI dependence on the climate variables. We used satellite time series to detect the land cover changes (areas of larch and Siberian pine, as well as shrubs and birch). We compared trees’ GI before and after warming “restart” in the late 1990s. Generally, GI dependence on the air temperature was negative at elevations below c. 1600 m a.s.l., whereas GI dependence on the moisture variables (precipitation, vapor pressure deficit, and soil moisture) was positive for both species. Above 1600 m, increasing air temperatures stimulated species growth, whereas the influence of moisture variables was negative (for larch) or neutral (for Siberian pine). After the warming restart, the GI of both conifers increased in moisture-sufficient high elevations and treeline ecotone, whereas within low elevations (<1300 m), the GI was stagnant or suppressed. Both species’, especially Siberian pine, negative growth dependence on air temperature and positive dependence on the moisture variables strongly increased since the warming restart. We found a risen growth dependence of both species on the soil-stored water during the previous year (September–October), which smoothed moisture stress at the beginning of the growing season. Yet both species’ growth also suffered as a result of early spring warms. We found that larch is migrating in both uphill and downhill directions, while Siberian pine is migrating uphill only. Forests loss occurred at low elevations (<1300 m), whereas forest and shrub gain occurred at high (>2000 m) ones. The upper boundary of the forests and shrubs is migrating uphill at rates of about 0.8 and 0.3 m/y, respectively. We observed a decrease in Siberian pine proportion in the forests, whereas areas of larch and birch strongly increased (by 150% and 100%, respectively), which indicates the retreat of Siberian pine from its southern habitat. We suggested afforestation of the areas of Siberian pine mortality by the drought-tolerant larch species.

Investigating soil properties on the north and south slopes at different elevations in Al-Jabal Al-Akhdar, Libya

This scholarly study investigated the physicochemical characteristics of soil in the Al-Jabal Al-Akhdar forest, Libya, with a specific focus on the influence of elevation and slope aspects. Fifty-six sample plots were established across varying elevations, each subdivided into four subplots, totaling 224. Soil samples were collected from each subplot at 0-15 cm depth. Results demonstrate significant variations in clay, silt, and sand content with elevation, indicating lower clay and higher sand content at higher elevations. Available water capacity (AWC) increased with altitude on the northern slope, while consistently lower values were observed on the southern slope. Bulk density (BD) decreased with increasing altitude, suggesting less compacted soils at higher elevations. Available phosphorus (Pav), available potassium (Kav), and pH values decreased with increasing altitude on both slopes. Cation exchange capacity (CEC) values varied at altitudes on the northern slope, with higher values observed at mid to high altitudes. Calcium carbonate (CaCO3) decreased with increasing altitude on the northern slope while showing inconsistent trends on the southern slope. Soil organic matter (SOM) content increased with altitude on both slopes. Pearson's correlation and Principal Component Analysis (PCA) examined relationships among soil properties, elevations, and aspects. Elevation positively correlated with AWC and SOM and negatively correlated with clay content, Kav, BD, and pH. PCA identified elevation, aspect, silt content, CaCO3, and electrical conductivity (EC) as primary influencers. SOM exhibited positive correlations with AWC and negative correlations with BD. Soil pH showed a negative correlation with SOM and a positive correlation with CaCO3. Additionally, CaCO3 content was positively correlated with the cation exchange capacity (CEC). These findings contribute to understanding soil property relationships, elevation, and aspect, emphasizing their role in shaping soil ecosystems and nutrient dynamics. Further research is warranted to explore additional factors influencing soil properties and to develop effective nutrient management strategies.