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05 March 2012, Volume 4 Issue 1 Previous Issue    Next Issue
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Journal of Arid Land. 2012, 4 (1): 1-2.  
Abstract ( 1714 )     PDF (132KB) ( 1920 )  
Research Articles
Impact of nitrogen addition on plant community in a semi-arid temperate steppe in China
Ling SONG, XueMei BAO, XueJun LIU, FuSuo ZHANG
Journal of Arid Land. 2012, 4 (1): 3-10.   DOI: 10.3724/SP.J.1227.2012.00003
Abstract ( 3412 )     PDF (372KB) ( 3050 )  
 Increased nitrogen (N) deposition will often lead to a decline in species richness in grassland ecosystems but the shifts in functional groups and plant traits are still poorly understood in China. A field experiment was conducted at Duolun, Inner Mongolia, China, to investigate the effects of N addition on a temperate steppe ecosystem. Six N levels (0, 3, 6, 12, 24, and 48 g N/(m2×a)) were added as three applications per year from 2005 to 2010. Enhanced N deposition, even as little as 3 g N/(m2×a) above ambient N deposition (1.2 g N/(m2×a)), led to a decline in species richness of the whole community. Increasing N addition can significantly stimulate aboveground biomass of perennial bunchgrasses (PB) but decrease perennial forbs (PF), and induce a slight change in the biomass of shrubs and semi-shrubs (SS). The biomass of annuals (AS) and perennial rhizome grasses (PR) accounts for only a small part of the total biomass. Species richness of PF decreased significantly with increasing N addition rate but there was a little change in the other functional groups. PB, as the dominant functional group, has a relatively higher height than others. Differences in the response of each functional group to N addition have site-specific and species-specific characteristics. We initially infer that N enrichment stimulated the growth of PB, which further suppressed the growth of other functional groups.
Relationship between dew presence and Bassia dasyphylla plant growth
YanLi ZHUANG, Sophia RATCLIFFE
Journal of Arid Land. 2012, 4 (1): 11-18.   DOI: 10.3724/SP.J.1227.2012.00011
Abstract ( 2833 )     PDF (657KB) ( 2506 )  
Dew has been recognized for its ecological significance and has also been identified as an additional source of water in arid zones. We used factorial control experiment, under dew presence in the field, to explore photosynthetic performance, water status and growth response of desert annual herbage. Bassia dasyphylla seedlings were grown in contrasting dew treatments (dew-absent and dew-present) and different watering regimes (normal and deficient). The effects of dew on the water status and photosynthetic performance of Bassia dasyphylla, grown in a desert area of the Hexi Corridor in Northwestern China, were evaluated. The results indicated the presence of dew significantly increased relative water content (RWC) of shoots and total biomass of plants in both water regimes, and enhanced the diurnal shoot water potential and stomatal conductance in the early morning, as well as photosynthetic rate, which reached its maximum only in the water-stressed regime. The presence of dew increased aboveground growth of plants and photosynthate accumulation in leaves, but decreased the root-to-shoot ratio in both water regimes. Dew may have an important role in improving plant water status and ameliorating the adverse effects of plants exposed to prolonged drought.
Reproduction of Hedysarum scoparium (Fabaceae) in patched habitat is pollen limited, but not just pollinator limited
ChengChen PAN, LinDe LIU, HaLin ZHAO, JiLiang LIU, YueLi HOU, Li ZHANG
Journal of Arid Land. 2012, 4 (1): 19-28.   DOI: 10.3724/SP.J.1227.2012.00019
Abstract ( 2728 )     PDF (530KB) ( 2477 )  
Pollen limitation of plant reproduction occurs across Angiosperms, particularly those in patched habitats. We investigated the relationship between pollen limitation and patch variables (patch size, visitation frequency) in the desert plant Hedysarum scoparium (Fabaceae), which is an important xerophyte in the arid and semi-arid regions of Northwest China and can grow well as a pioneer plant in shifting sand dunes. We observed insect visitation to H. scoparium over two flowering seasons and estimated pollen limitation using fruit set and seed production. Our results indicate that fruit set and seed production increased significantly with pollen supplementation compared with open pollination. Hedysarum scoparium was pollinated by over 8 species of bees, with 88.4% of visits made by introduced honeybees (Apis mellifera). Bee visitation varied significantly among the patches of habitats, but not associated with patch size of habitat. In general, pollen limitation occurred more strongly during fruit set than during seed production. The patches that received higher rates of pollinator visits were less pollen limited for fruit set. Pollen limitation for seed production, however, was not associated with pollinator visitation frequency. We conclude that pollen limitation in H. scoparium was caused by more than one reason, not just pollinator visits.
Impacts of livestock grazing on a savanna grassland in Kenya
John KIOKO, John Warui KIRINGE, Simon Ole SENO
Journal of Arid Land. 2012, 4 (1): 29-35.   DOI: 10.3724/SP.J.1227.2012.00029
Abstract ( 4165 )     PDF (662KB) ( 7442 )  
The dynamics of most rangelands in Kenya remain to be poorly understood. This paper provides baseline information on the response of a semiarid rangeland under different livestock grazing regimes on land inhabited by the Massai people in the east side of Amboseli National Park in Kenya. The data were collected from grasslands designated into four types: (1) grassland from previous Massai settlements that had been abandoned for over twenty years; (2) grassland excluded from livestock grazing for eight years; (3) a dry season grazing area; and (4) a continuous grazing area where grazing occurred throughout all seasons. Collected data included grass species composition, grass height, inter-tuft distance, standing grass biomass and soil characteristics. The results indicated that continuous grazing area in semiarid rangelands exhibited loss of vegetation with negative, long-term effects on grass functional qualities and forage production, whereas grassland that used traditional Maasai grazing methods showed efficiency and desirable effects on the rangelands. The results also showed that abandoned homestead sites, though degraded, were important nutrient reservoirs.
Comparison of seed germination of four Artemisia species (Asteraceae) in northeastern Inner Mongolia, China
XueHua LI, DeMing JIANG, Alamusa, QuanLai ZHOU, Toshio OSHIDA
Journal of Arid Land. 2012, 4 (1): 36-42.   DOI: 10.3724/SP.J.1227.2012.00036
Abstract ( 2906 )     PDF (505KB) ( 3933 )  
Two psammophile-dominated Artemisia semi-shrubs (A. wudanica and A. halodendron) and two annual Artemisia forbs (A. sieversiana and A. scoparia) bear significant ecological functions in Horqin Sandy Land, but systematical information on their achenes’ germination is very limited. A set of studies were conducted to evaluate seed germination responses to storage periods and methods, different temperatures, lights conditions and sand burial depths, in order to determine inter-specific germination variation in the same genus and to explain how the species adapt to its microhabitat. Fresh achenes of A. wudanica, A. halodendron and A. sieversiana showed high germination capacities, but those of A. scoparia had obvious innate dormancy, which could be broken by chilling and dry storage, especially long-term dry storage. Achene germination of the two semi-shrubs preferred lower temperature fluctuation (10 to 22ºC) and was not sensitive to light. But the two annuals preferred higher temperature fluctuation (34 to 22ºC) and strong light for their achene germination. These four Artemisia species showed similar responses to sand burial, i.e. soil surface was most favorable for seedling emergence, and the deeper the sand burial, the fewer the seedling emergence. For the two semi-shrubs, their microhabitats are sand dunes with high temperature and intense light, which are not favorable for germination and seedling survival. Only rainfall contributes to temporary decrease of temperature and then triggers germination. We deduced that germination is not the main but a supplementary reproductive mode for the two semi-shrubs in sand dunes. For the two annuals, achene germination is the only reproductive mode, but different responses have been developed for microhabitat adaptation. For A. sieversiana, high germination capacities in wide temperature ranges and all light conditions could improve its competition and advancement in the wettest microhabitats. For A. scoparia, obvious innate dormancy of fresh achenes and germination inhabitation under unfavorable conditions are important adaptation to environmental disturbances.
Dynamics of arbuscular mycorrhizal fungi associated with desert ephemeral plants in Gurbantunggut Desert
Tao ZHANG, ChangYan TIAN, Yu SUN, DengSha BAI, Gu FENG
Journal of Arid Land. 2012, 4 (1): 43-51.   DOI: 10.3724/SP.J.1227.2012.00042
Abstract ( 3942 )     PDF (596KB) ( 3686 )  
Previous studies documented that most desert plants can be colonized by arbuscular mycorrhizal (AM) fungi, however, little is known about how the dynamics of AM fungi are related to ephemerals in desert ecosystems. The dynamics of AM fungi with desert ephemerals were examined to determine the effects of host plant life stages on the development of AM fungi. Mean colonization of ephemeral annual plants was 45% lower than that of ephemeral perennial plants. The colonizations were much higher in the early part of the growing season than in later parts, peaking at flowering times. The phenology of AM fungi in root systems varied among different ephemerals. The density of AM fungal spores increased with the development of ephemeral annual plants, reached its maximum at flowering times, and then plateaued about 20 days after the aboveground senescence. A significant positive correlation was found between AM fungi spore density and biomass of ephemeral annual plants. The life cycles of AM fungi associated with desert ephemerals were very short, being about 60–70 days. Soil temperature and water content had no direct influence on the development of AM fungal spores. We concluded that the development of AM fungi was in response to desert ephemeral phenology and life history strategy.
Retrieval of leaf biochemical properties by inversed PROSPECT model and hyperspectral indices: an application to Populus euphratica polymorphic leaves
ZhongGuo MA, Xi CHEN, Quan WANG, PingHeng LI, Guli Jiapaer
Journal of Arid Land. 2012, 4 (1): 52-62.   DOI: 10.3724/SP.J.1227.2012.00052
Abstract ( 3967 )     PDF (1122KB) ( 3193 )  
Leaf biochemical properties have been widely assessed using hyperspectral reflectance information by inversion of PROSPECT model or by using hyperspectral indices, but few studies have focused on arid ecosystems. As a dominant species of riparian ecosystems in arid lands, Populus euphratica Oliv. is an unusual tree species with polymorphic leaves along the vertical profile of canopy corresponding to different growth stages. In this study, we evaluated both the inversed PROSPECT model and hyperspectral indices for estimating biochemical properties of P. euphratica leaves. Both the shapes and biochemical properties of P. euphratica leaves were found to change with the heights from ground surface. The results indicated that the model inversion calibrated for each leaf shape performed much better than the model calibrated for all leaf shapes, and also better than hyperspectral indices. Similar results were obtained for estimations of equivalent water thickness (EWT) and leaf mass per area (LMA). Hyperspectral indices identified in this study for estimating these leaf properties had root mean square error (RMSE) and R2 values between those obtained with the two calibration strategies using the inversed PROSPECT model. Hence, the inversed PROSPECT model can be applied to estimate leaf biochemical properties in arid ecosystems, but the calibration to the model requires special attention.
Correlation of soil properties and fruit size of Callgonum mongolicum and related species
Wei SHI, BoRong PAN, Habibullo SHOMURODOV
Journal of Arid Land. 2012, 4 (1): 63-70.   DOI: 10.3724/SP.J.1227.2012.00063
Abstract ( 2575 )     PDF (224KB) ( 1466 )  
Correlations of soil properties and fruit size of Calligonum mongolicum Turcz. and related species were analyzed. The results showed that the particle size characteristics of soils for growing Calligonum mongolicum and related species were similar, and the soils belonged to sandyones. The organic matter contents of soils were low (averaging 1.772 to 3.054 g/kg), and the total salt content of soils was low too (averaging 0.471 g/kg). The pH values indicated that the soils were alkaline, varying from pH 7.65 to 10.25. The results of Principal Component Analysis (PCA) and hierarchical cluster showed that 9 habitats could be divided into 6 types according to salt contents and pH values. Fruit sizes of different populations and the soil properties had significant linear correlations (P<0.000). It was concluded that the differences in fruit sizes among the populations of Calligonum mongolicum and related species were related to soil variability, especially the nutrient contents of soils, and fruit size can not be considered as a taxonomic index of Calligonum mongolicum and related species.
Variability and divergence in horsegram (Dolichos uniflorus)
Kanaka K DURGA
Journal of Arid Land. 2012, 4 (1): 71-76.   DOI: 10.3724/SP.J.1227.2012.00071
Abstract ( 2626 )     PDF (442KB) ( 3666 )  
 Horsegram is an important and unexploited tropic and sub-tropic legume crop grown mostly in dry land agriculture. The study involving 23 cultivars of horsegram (Dolichos uniflorus) was conducted at the Seed Research & Technology Centre in Rajendranagar, Hyderabad, India during the early spring seasons of 2008 and 2009 to assess the nature and magnitude of variability in the existing species and also to identify diverse parents for use in further breeding programmes. The results indicated significant differences among the 23 cultivars for all characters studied, indicating the presence of sufficient genetic variation. High variability and heritability coupled with high genetic advance were reported for seed yield per plant and pod hulm per plant, indicating additive gene action and a possible scope for the improvement of these characters. Mahalanobis D2 statistics grouped all the 23 cultivars of horsegram into six clusters. The maximum inter cluster distance (62.39) was noticed between cluster IV (HG 50) and cluster V (HG 11). The maximum intra cluster distance ranged from 0 (clusters III, IV, V and VI) to 15.17 (cluster ?), indicating that the genotypes in these clusters were relatively more diverse than the genotypes within other clusters. Seed yield per plant contributed the maximum (33.20%) to the genetic divergence.
Range extension of four highland agamid lizards in Shimshal Pamir, Pakistan
Babar KHAN, Waseem AHMED, Abdukadir Ablimit, Shamim FAKHRI, Hassan ALI
Journal of Arid Land. 2012, 4 (1): 77-84.   DOI: 10.3724/SP.J.1227.2012.00077
Abstract ( 2756 )     PDF (5825KB) ( 3586 )  
As part of the Sino-Pak trans-boundary cooperation for conservation and sustainable development in Pamir border region, World Wild Fund (WWF)-Pakistan conducted a preliminary social, economic and ecological survey in the Shimshal-Pamir Lakes area in July 2009. The purpose of the study was to explore potentials and opportunities for future collaborative conservation of some species, habitats and high altitude ecosystems in the border region between China and Pakistan. The two-week herpetological study in the Shimshal Pamir area of Khunjerab National Park (KNP) along Pakistan-China border was an integral part of the survey, conducted exclusively to document reptilian fauna with a special emphasis on investigating their occurrence, distribution and status in the study area. Field investigations were performed during daytime when it was hot enough and reptiles were active, basking or feeding. A total of 15 specimens belonging to four species of the Agamidae family were captured by striking stones and beating bushes with sticks. Collected specimens were preserved using 10% formalin solution, tagged with field information and stored in Zoological Survey Department, Karachi for future reference. Laboratory investigations were carried out for pholidosic counts and morphometric measurements. A detailed review of relevant literature, habitat characteristics and laboratory investigations revealed the occurrence of Laudakia himalayana, L. pakistanica, L. tuberculata and L. badakhshana at 4,082 m, 4,172 m, 4,005 m and 4,240 m asl, respectively, which are much higher altitudes as compared to the previously reported heights of 3,353 m, 3,200 m, 2,500 m and 2,400 m asl. The terrain offers a variety of ecological barriers, in the form of fast and freezing running waters and massive glaciers with peculiar harsh climatic conditions prevailing for nine months of the year, which restricts species migration and thus increases endemism. Although one of the four species recorded from the study area, i.e. L. pakistanica is endemic to Pakistan, L. tuberculata and L. badakhshana are new records from Shimshal, Pakistan, so a detailed investigation is suggested for further herpetological records from the study area.
The migration of total dissolved solids during natural freezing process in Ulansuhai Lake
Yan ZHANG, ChangYou LI, XiaoHong SHI, Chao LI
Journal of Arid Land. 2012, 4 (1): 85-94.   DOI: 10.3724/SP.J.1227.2012.00085
Abstract ( 3899 )     PDF (833KB) ( 2641 )  
High total dissolved solids (TDS) content is one of the most important pollution contributors in lakes in arid and semiarid areas. Ulansuhai Lake, located in Urad Qianqi, Inner Mongolia, China, was selected as the object of study. Temperatures and TDS contents of both ice and under-ice water were collected together with corresponding ice thickness. TDS profiles were drawn to show the distribution of TDS and to describe TDS migration. The results showed that about 80% (that is 3.602×108 kg) of TDS migrated from ice to water during the whole growth period of ice. Within ice layer, TDS migration only occurred during initial ice-on period, and then per-ished. The TDS in ice decreased with increasing ice thickness, following a negative exponential-like trend. Within under-ice water, the TDS migrated from ice-water interface to the entire water column under the effect of concentration gradient until the water TDS content was uniform. In winter, 6.044×107 kg (16.78% of total TDS) TDS migrated from water to sediment, which indicated that winter is the best time for dredging sediment. The migration effect gives rise to TDS concentration in under-ice water and sediment that is likely to affect ecosystem and water quality of the Yellow River. The trend of transfer flux of ice-water and water-sediment interfaces is similar to that of ice growth rate, which reveals that ice growth rate is one of the determinants of TDS migration. The process and mechanism of TDS migration can be referenced by research on other lakes with similar TDS content in cold and arid areas.
Ecological migration effects on the Tianchi Scenic Area in Xinjiang: from the perspective of migrant farmer families
Hong TANG, DeGang YANG, XinHuan ZHANG, XinYi XIANG
Journal of Arid Land. 2012, 4 (1): 95-104.   DOI: 10.3724/SP.J.1227.2012.00095
Abstract ( 2944 )     PDF (1926KB) ( 2540 )  
As an important approach for relieving conflicts between ecosystems and human activities in the Tianchi Scenic Area, Xinjiang of China, an ecological migration policy was implemented, aiming to improve the regional ecological environment. The case of resettlement was closely related to the smooth implementation of the migration project. Based on the questionnaires and farmer family interviews, both changes in the ecological environment and the living conditions of migrant farmer families in the Tianchi Scenic Area were investigated in this study. The objectives were to assess the benefits of the ecological migration policy and to analyze the effects of ecological migration on migrant farmer families. The results showed that (1) awareness of the need for ecological environmental protection and the types of migrant families had a great influence on the willingness to migration; (2) since the implementation of the ecological migration project, the ecological environment in the Tianchi Scenic Area had improved significantly, particularly in terms of returning farmland to forestry, while pressures on grassland had also been relieved to some extent; (3) the major income sources and occupations of the migrant farmer families changed, the range of their income sources declined, and their per capita incomes decreased at different degrees; and (4) nearly half of the farmer families were not satisfied with the living environment of new settlements and the decline in the quality of life had significant influences on the attitudes of migrants. In order to ensure the successful implementation of an ecological migration project, it is essential to enhance farmer awareness of needs for ecological environmental protection, and to solve resettlement problems properly.
Spatio-temporal pattern and changes of evapotranspiration in arid Central Asia and Xinjiang of China
Xi CHEN, BaiLian LI, Qin LI, JunLi LI, Saparnov ABDULLA
Journal of Arid Land. 2012, 4 (1): 105-112.   DOI: 10.3724/SP.J.1227.2012.00105
Abstract ( 4431 )     PDF (8278KB) ( 3853 )  
Accurate inversion of land surface evapotranspiration (ET) in arid areas is of great significance for understanding global eco-hydrological process and exploring the spatio-temporal variation and ecological response of water resources. It is also important in the functional evaluation of regional water cycle and water balance, as well as the rational allocation and management of water resources. This study, based on model validation analysis at varied scales in five Central Asian countries and China’s Xinjiang, developed an appropriate approach for ET inversion in arid lands. The actual ET during growing seasons of the study area was defined, and the changes in water participating in evaporation in regional water cycle were then educed. The results show the simulation error of SEBS (Surface Energy Balance System) model under cloud amount consideration was 1.34% at 30-m spatial scale, 2.75% at 1-km spatial scale and 6.37% at 4-km spatial scale. ET inversion for 1980–2007 applying SEBS model in the study area indicates: (1) the evaporation depth (May–September) by land types descends in the order of waters (660.24 mm) > cultivated land (464.66 mm) > woodland (388.44 mm) > urbanized land (168.16 mm) > grassland (160.48 mm) > unused land (83.08 mm); and (2) ET during the 2005 growing season in Xinjiang and Central Asia was 2,168.68×108 m3 (with an evaporation/precipitation ratio of 1.05) and 9,741.03×108 m3 (with an evaporation/precipitation ratio of 1.4), respectively. The results unveiled the spatio-temporal variation rules of ET process in arid areas, providing a reference for further research on the water cycle and water balance in similar arid regions.