Nival Areas Research Articles

Effect of Glacial Retreat on Floral Distribution and/or Displacement in Khersan Glacier, Central Alborz Mountain range, Iran

During past few decades, worldwide various ecological alterations have beenexperienced after treatand decreasing of glaciers. Notable changes have been traced in Khersan glacier, Central Alborz of Iran by monitoring since 2013 to 2015. According to our studies, Khersan glacier surface reduced since 1991 and this signif icant reduction led to manyecological alterations. Specieseliminationclose to the glacier, displacement of various flora from sub-Alpine to Alpine and Nival area including changes in floral frequency are notable alterations taken during glacier retreat. A large number of studies in Khersan glacier area since last two centuries have evidenced complete elimination of 6 plant species. Displacement of 16 plant species during recent years revealed that such species after retreat either found a new location for the establishment or got eliminated. Besides natural changes, the glacierareawasalsoaffected by man-made developments. Perhaps new condition puts many plant species in conservation level which need proper care programs. In this study multidimensional scaling model (MDS) is used to show the Nival areas where species are under muchstress. Properevidence has been tried toput forward fordescribing suchchanges. Abstract

Recent climatic events controlling the hydrological and the aquifer dynamics at arid areas: The case of Huasco River watershed, northern Chile

The investigation assesses the influence of recent climatic events in the water resources and the aquifer dynamics in the Huasco watershed by means of the analysis of precipitation, streamflow and piezometric levels during the last 50years. These hydrological and hydrogeological parameters were evaluated by an exploratory geostatistical analysis (semivariogram) and a spectral analysis (periodogram). Specifically, the hydrological and hydrogeological data analyses are organized according to three sub-basins, the Del Carmen River (Section I), the El Tránsito River (Section II), and the Huasco River (Section III). Data ranges for rainfall are from 1961 to 2015, for streamflow from 1964 to 2015, and for groundwater levels from 1969 to 2014, available from Water Authority of Chile. The analyses allowed the identification of cycles in the hydrological and hydrogeological records. The study area is located in a transient climatic fringe where the convergence of several climatic systems can be identified in the hydrological and hydrogeological records. Results indicate that the nival areas and the small glaciers are especially important to the recharge processes in the Huasco watershed during the spring-summer snowmelting. Water reservoirs in the main aquifer (Section III) and in the Santa Juana dam are highly sensitive to ENSO oscillation climatic patterns. The main climatic events that control this record are the El Niño and La Niña events. In addition, the climatic influence of the westerlies and the SE extratropical moisture were also identified. Spectral analysis identified the presence of a 22.9-yearcycle in piezometric levels of the alluvial aquifer of the Huasco River. This cycle is consistent with the 22-year Hale solar cycle, suggesting the existence of a solar forcing controlling the ENSO oscillations. Moreover, semivariogram and spectral analysis identified a 10.65-yearcycle and a 9.2-yearcycle in groundwater, respectively, which were attributed to the strong mode of ENSO oscillations.

Scenarios of land cover in Karst area of Southwestern China

The method of surface modeling of land cover scenarios (SMLCS) has been improved to simulate the scenarios of land cover in the karst areas of southwestern China. On the basis of the observation monthly climatic data collected from 782 weather stations of China during the period from 1981 to 2010, the climatic scenarios data of RCP26, RCP45 and RCP85 scenarios released by CMIP5, and the land cover current data of China in 2010, the land cover scenarios of southwestern China were respectively simulated. The average total accuracy and Kappa index of SMLCS are 90.25 and 87.96 %, respectively. The results show that there would be a very apparent similar variety on the spatial distribution pattern of land cover in the karst areas of southwestern China under all the three scenarios during the period from 2010 to 2100, but there would have the different change rate. In general, the change rate of land cover type under RCP85 scenario would be the fastest, then under RCP45 scenario, and under RCP26 would be the slowest. From 2010 to 2100, deciduous coniferous forest, deciduous broadleaf forest, grassland, cropland, nival area, and desert and bare rock would have a gradual decrease trend, while evergreen coniferous forest, evergreen broadleaf forests, mixed forest, scrublands, wetlands, construction built-up land, and water bodies body would gradually increase in karst areas of southwestern China, in which wetland would have the fastest increase rate (5.28 % per decade on average), and desert and bare rock would decrease with the fastest rate (2.34 % per decade on average).

Scenarios of changes in the spatial pattern of land use in China

Land use changes affect many aspects of Earth System functioning, for example in impacting global carbon cycle, contributing to climate change, or increasing soil erosion. The simulation of land use change is important in environmental impact assessment and land use planning. We assessed the land use scenarios of China in the next 100 years based on the SMLC (surface modelling of land cover change) model and Dyna-CLUE (dynamic conversion of land use and its effects) model. Three SRES scenarios were evaluated: Global Economy (A1FI): lean government, strong globalization; Continental Markets (A2a): lean government, regional culture and economic development; Regional communities (B2a): much government intervention, regional cultural and economic development. Ten land cover types were simulated, which are cultivated land, woodland, grassland, built-up land, water area, wetland, nival area, desert, bare rock and desertification land. The SMLC model was used to calculate changes in area for each land use types in the future at country level while the spatially explicit land use model Dyna-CLUE was used to simulate land use pattern at 2 km2 resolution based on the country level areas demands for each land cover type. The results show that the cultivated land would decrease in all of the three scenarios, while in the A2a scenario, the cultivated land would decrease with the lowest rate because of the high population growth, high level of market protection and low agricultural efficiency; in the B2a scenario, it would decrease with the highest rate caused by the decreased population numbers and increased crop productivity. The nival area would decrease with the highest rate in the A1FI scenario since the rapid introduce of new technology and the energy system is fossil intensive, which would discharge more greenhouse gas than other two scenarios. The area of natural ecosystems such as wood land, grassland, water area and wet land would increase significantly in the B2a scenario because this scenario puts more weight on environmental sustainability. The land use spatial pattern in China under the B2a scenario is simulated. The results are important to identify hotspots of land use change that need specific attention by the governments and the researchers.

Changes of Climate-Vegetation Ecosystem in Loess Plateau of China

Abstract The change of terrestrial ecosystem spatial distribution driven by climatic change is one of important factors leading to soil erosion in Loess Plateau. The quantitative analysis of climate change impacting on vegetation ecosystem will afford the efficient data to support the implement of reasonability ecological restoration project. HLZ ecosystem model is employed to simulate the changes of climate-vegetation ecosystem in Loess Plateau during the periods from 1964 to 1974 (C1), from 1975 to 1985 (C2), from 1986 to 1996 (C3), and from 1997 to 2007(C4) on spatial resolution of 1km×1 km. Combining the elevation data, the results show that there are 15 types of climate-vegetation ecosystem in which the cool temperate steppe, cool temperate moist forest and warm temperate are the major climate-vegetation types which respectively occupied the 82.73%, 83.19%, 82.86% during the periods from C1 to C4, and 79.77% of the sum area of Loess Plateau. The most types of moist climate-vegetation ecosystems have decreased since C1 period, especially the area of nival area, alpine wet tundra and alpine rain tundra have rapidly decreased during the four periods. Furthermore, the average distribution elevation of all climate-vegetation ecosystems distribution are on the increase except warm temperate thorn steppe, especially the average distribution elevation of alpine rain tundra, boreal wet forest, cool temperate scrub and warm temperate dry forest have continuously increased during the four periods.

The subnival–nival vascular plant species of Iran: a unique high-mountain flora and its threat from climate warming

This study provides a first country-wide overview of the vertical distribution patterns and the chorology of vascular plant species that occur in the uppermost elevation zones in Iran. The current distribution patterns are discussed with respect to potential warming-induced species losses. Iran’s subnival and nival vegetation zones are found at elevations above 3600–3900 m in a highly fragmented distribution across Alborz, Zagros, and NW-Iran. Based on literature research and on field observations, all vascular plant species living in the subnival–nival zone of Iranian mountains were identified (151 species) and classified into three altitudinal groups: Group A comprises species that occur mainly in subnival–nival habitats (51 species). Group B are species being common in subnival–nival areas but are equally present in the alpine zone (56 species). Group C are species that can reach to subnival areas but also grow in alpine, subalpine and sometimes lower altitudes (44 species). The chorological patterns differ among the three groups. The percentage of species being endemic to Iran decreases from group A, to B and C, with 68, 53 and 20%, respectively. A narrow altitudinal distribution at high elevations is clearly related to a small-scaled geographical distribution range. The outstanding rate of high-altitude endemism appears to result mainly from orographic isolation of the country’s highly scattered cold areas and by the absence of extensive Pleistocene glaciations. The narrow distribution of most of Iran’s cold-adapted mountain flora and the low potential of alternative cold habitats render it highly vulnerable to climate change.

Surface modelling of global terrestrial ecosystems under three climate change scenarios

A high accuracy and speed method (HASM) of surface modelling is developed to find a solution for error problem and to improve computation speed. A digital elevation model (DEM) is established on spatial resolution of 13.5 km × 13.5 km. Regression formulations among temperature, elevation and latitude are simulated in terms of data from 2766 weather observation stations scattered over the world by using the 13.5 km × 13.5 km DEM as auxiliary data. Three climate scenarios of HadCM3 are refined from spatial resolution of 405 km × 270 km to 13.5 km × 13.5 km in terms of the regression formulations. HASM is employed to simulate surfaces of mean annual bio-temperature, mean annual precipitation and potential evapotranspiration ratio during the periods from 1961 to 1990 (T 1), from 2010 to 2039 (T 2), from 2040 to 2069 (T 3), and from 2070 to 2099 (T 4) on spatial resolution of 13.5 km × 13.5 km. Three scenarios of terrestrial ecosystems on global level are finally developed on the basis of the simulated climate surfaces. The scenarios show that all polar/nival, subpolar/alpine and cold ecosystem types would continuously shrink and all tropical types, except tropical rain forest in scenario A1Fi, would expand because of the climate warming. Especially at least 80% of moist tundra and 22% of nival area might disappear in period T 4 comparing with the ones in the period T 1. Tropical thorn woodland might increase by more than 97%. Subpolar/alpine moist tundra would be the most sensitive ecosystem type because its area would have the rapidest decreasing rate and its mean center would shift the longest distance towards west. Subpolar/alpine moist tundra might be able to serve as an indicator of climatic change. In general, climate change would lead to a continuous reduction of ecological diversity.

Scenarios of land cover in China

A method for surface modeling of land cover change (SMLC) is developed on the basis of establishing transition probability matrixes between land cover types and HLZ types. SMLC is used to simulate land cover scenarios of China for the years 2039, 2069 and 2099, for which HLZ scenarios are first simulated in terms of HadCM3 climatic scenarios that are downscaled in zonal model of spatial climate change in China. This paper also analyzes spatial distribution of land cover types, area change and mean center shift of each land cover type, ecotope diversity, and patch connectivity under the land cover scenarios. The results show that cultivated land would decrease and woodland would expand greatly with climatic change, which coincides with consequences expected by implementation of Grain-for-Green policy. Nival area would shrink, and desertification area would expand at a comparatively slow rate in future 100 years. Climate change would generally cause less ecotope diversity and more patch connectivity. Ecosystems in China would have a pattern of beneficial cycle after efficient ecological conservation and restoration. However, if human activities would exceed regulation capacity of ecosystems themselves, the ecosystems in China might deteriorate more seriously.

Scenarios of major terrestrial ecosystems in China

The spatial pattern and mean-center shift of major terrestrial ecosystems, termed Holdridge Life Zones (HLZ), during the periods from 1961 to 1990 (T1), from 2010 to 2039 (T2), from 2040 to 2069 (T3) and from 2070 to 2099 (T4) were analyzed by combining the zonal patterns of climatic change in China and the climatic change scenarios of HadCM2 and HadCM3. The results showed that nival area would decrease rapidly with temperature increase in the future. HadCM2 and HadCM3 predicted that the nival areas might disappear in 552 years and 204 years, respectively. Using both HadCM2 and HadCM3, the five HLZ types with the largest areal extent are nival zone, cool temperate moist forest, warm temperate moist forest, subtropical moist forest and boreal wet forest, which collectively account for more than 50% of China's land mass. Among these five HLZ types, nival zone, warm temperate moist forest and boreal wet forest would decrease continuously, whereas subtropical moist forest and cool temperate forest would increase continuously during the four periods. HLZ diversity and patch connectivity would increase continuously in the 21st century. The shift distances of mean centers of HLZ types simulated using HadCM3 were markedly greater than those simulated using HadCM2, in general. The results from both HadCM2 and HadCM3 showed that boreal wet forest, subtropical moist forest, tropical dry forest, warm temperate moist forest and subtropical wet forest had bigger shift ranges, indicating that these HLZ types are more sensitive to the climatic change scenarios of HadCM2 and HadCM3.

Divergent vegetation growth responses to the 2003 heat wave in the Swiss Alps

In 2003, Europe experienced its hottest summer in >500 years. Satellite‐derived photosynthetic activity estimates across the Alps revealed a pattern of high elevation growth enhancement and low elevation growth suppression in response to these extreme summer temperatures. Surface weather‐derived effective growing season lengths were shorter in 2003 by an average of 9% and 5% for colline and montane areas respectively and were 2%, 12% and 64% longer for subalpine, alpine and nival areas respectively. In situ forest growth measurements of 244 trees at 15 sites across Switzerland verified this pattern and revealed that this divergent response was consistent between species. We suggest that warmer summer temperatures lengthened the snow‐free growing season at high elevations while they increased summertime evaporative demand at lower elevations. Our investigation demonstrates that climatic changes are affecting plants beyond simply shifting the elevation belts upwards.

Changes of major terrestrial ecosystems in China since 1960

Daily temperature and precipitation data since 1960 are selected from 735 weather stations that are scattered over China. After comparatively analyzing relative interpolation methods, gradient-plus-inverse distance squared (GIDS) is selected to create temperature surfaces and Kriging interpolation method is selected to create precipitation surfaces. Digital elevation model of China is combined into Holdridge Life Zone (HLZ) model on the basis of simulating relationships between temperature and elevation in different regions of China. HLZ model is operated on the created temperature and precipitation surfaces in ARC/INFO environment. Spatial pattern of major terrestrial ecosystems in China and its change in the four decades of 1960s, 1970s, 1980s and 1990s are analyzed in terms of results from operating HLZ model. The results show that HLZ spatial pattern in China has had a great change since 1960. For instance, nival area and subtropical thorn woodland had a rapid decrease on an average and they might disappear in 159 years and 96 years, respectively, if their areas would decrease at present rate. Alpine dry tundra and cool temperate scrub continuously increased in the four decades and the decadal increase rates are, respectively, 13.1% and 3.4%. HLZ patch connectivity has a continuous increase trend and HLZ diversity has a continuous decrease trend on the average. Warm temperate thorn steppe, subtropical wet forest and cool temperate wet forest shifted 1781.45 km, 1208.14 km and 977.43 km in the four decades, respectively. These HLZ types are more sensitive to climate change than other ones. These changes reflect the great effects of climate change on terrestrial ecosystems in China.

The conservation status of New Zealand's indigenous grasslands

The conservation status of New Zealand's indigenous grasslands was assessed against an 1840 baseline, immediately prior to European settlement, when they were of maximum extent. Five major types were recognised, four of them tussock grasslands. The assumed baseline extent of areas with at least some grassland dominance was mapped on the basis of the best available information. Their current extent was derived from the “tussock” category in Land Cover Data Base 1 map (typed as for the baseline map) and the areas formally protected (as at September 2002) from Department of Conservation records. Ecological region boundaries were added and the map information scanned and compiled using ArcGIS. North Island areas were also assessed as one unit while South Island was divided into three geographic regions based on general land use patterns: western wet non‐rangeland, rain‐shadow rangeland, and eastern lower altitude non‐rangeland regions. Of the total baseline extent of indigenous grasslands (82 432 km2 or c. 31% of the land area), about 13% was low‐alpine snow tussock grassland, 18% montane to subalpine snow tussock grassland, 23% montane to low‐alpine tall red/copper tussock grassland, 44% montane to subalpine short‐tussock grassland, and c. 2% lowland sward grassland. Most grassland (57%) was in the South Island rangeland region which also had the greatest extent of all four major tussock grassland types. Remaining areas of each grassland type vary largely with altitude and climate, the drier lower‐elevation grasslands showing the greatest reduction. Protection of the remaining indigenous grasslands, with various degrees of modification and/or degradation, is greatest in the South Island wet western region (89% of the 98% which remained as of September 2002), with less in the North Island (40% of the remaining 17%), and eastern South Island non‐rangeland region (11% of the remaining 3%). Grassland protection in the rangelands (12% of the remaining 76%) is currently increasing through tenure review of the Crown‐owned pastoral leases in this region. Indigenous temperate grasslands, claimed to be the world's most beleaguered biome (currently 4.59% protected), attain about 12.3% protection of the baseline area in New Zealand (or 28% of the 44% of remaining baseline extent), though biased towards the uplands. Data sets are available as ArcGIS shape files for indigenous grasslands at both 2002 and 1840, on an ecological region basis, as well as for high‐alpine and nival areas for the same periods and regions.