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Genetic diversity of Mansonia altissima A. Chev. under different regimes of human impact in the Akure Forest Reserve,Nigeria

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Forestry Studies in China 2010年第4期12卷 193-200页

作者： Akindele AKINNAGBE Oliver GAILING Reiner FINKELDEY Department of Forest Genetics and Forest Tree Breeding Georg August University

Mansonia altissima is an important West African timber tree species. For the purpose of examining the effect of human impact on its genetic diversity, genetic diversity and spatial genetic structure of the species under different regimes of human impact were investigated in the Akure Forest Reserve, Nigeria, using 504 amplified fragment length polymorphism （AFLP） markers. The results indicate a very low genetic diversity in M. altissima within the forest reserve （He = 0.045; PPL = 16.75%; Br = 1.162）. The highest genetic diversity was observed in the primary forest （H e= 0.062; PPL - 21.00%; Br = 1.204）, with the lowest genetic diversity in the isolated forest patch （He = 0.032; PPL = 9.00%; B r= 1.089）. A significant and pronounced spatial genetic structure was found in the logged forest and in the isolated forest patch. In contrast, the primary forest exhibited very weak spatial genetic structuring. As expected, no spatial genetic structure was found in the planted stands of M. altissima. From a conservation point of view, our results suggest that genetic diversity ofM. altissima is at risk in the forest reserve. The scale of human impact in the study area could pose a serious threat to the maintenance of genetic diversity of the species. These results would offer practical applications in the conservation of other tropical tree species.

关键词： AFLP Mansonia altissima human impact genetic diversity spatial genetic structure tropical rainforests

Landscape pattern and its effect on ecosystem functions in Seoul Metropolitan area:Urban ecology on distribution of the naturalized plant species

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Journal of Environmental Sciences 2003年第2期15卷 199-204页

作者： Sun-Kee Hong In-Ju Song Hyun-Ok Kim Eung-Kyong Lee Environmental Planning Institute Seoul National UniversitySeoul Development InstituteTechnical University BerlinEnvironmental Planning Institute Seoul National University Seoul 151-742 Korea Seoul 100-250 KoreaGermanySeoul 151-742 Korea

During land transformation process in the human history, naturalized plants were introduced to several land use patterns by the different ways of plant itself. Including some naturalized plants that had been contribute to land restoration, many naturalized plants have been invaded to original habitat or landscape for native plants. Once the plants were colonized, they extend their area and population size. Urban developed areas often give an important role of source habitat for naturalized plants and expanding their population size. In recent, this situation is appearing as one of environmental problems about the urban landscape management controlling the naturalized plants that invaded in the developed area and conserving the native vegetation. This paper is focusing on relationships between distribution of habitat of naturalized plants and landscape patch in urban area in Seoul. Gangdong-Gu, one of the administrative areas in Seoul was selected for this study. We examined the recent land use change using LANDSAT TM data and spreading of the representative naturalized plants (Robinia pseudoacacia and Eupatorium rugosum) by Seoul Biotope Mapping Project and field survey in 1999. As a result, these two species were often occurred in the same habitat and distributed in forest edge disturbed by man. Their distribution patterns were related to landscape indices (patch size and shape) in the forest edge.

关键词： biotope mapping ecosystem management human impact landscape pattern naturalized plants urban ecology

Denaturing gradient gel electrophoresis fingerprinting of soil bacteria in the vicinity of the Chinese Great Wall Station, King George Island, Antarctica

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Journal of Environmental Sciences 2013年第8期25卷 1649-1655页

作者： Qi Pan Feng Wang Yang Zhang Minghong Cai Jianfeng He Haizhen Yang Key Laboratory of Yangtze River Water Environment Ministry of Education College of Environmental Science and Engineering Tongji University Jinan Municipal Engineering Design and Research Institute Co. Ltd. Key Laboratory for Polar Science of State Ocean Administration Polar Research Institute of China

Bacterial diversity was investigated in soil samples collected from 13 sites around the Great Wall Station, Fildes Peninsula, King George Island, Antarctica, using denaturing gradient gel electrophoresis （DGGE） of 16S rRNA genes. The classes α-, β-, and γ-Proteobacteria, as well as the phylum Actinobacteria, were found to be the dominant bacteria in the soils around the Great Wall Station. Although the selected samples were not contaminated by oil, a relationship between soil parameters, microbial biodiversity, and human impact was still seen. Sample sites in human impacted areas showed lower bacterial biodiversity （average H′= 2.65） when compared to nonimpacted sites （average H′= 3.05）. There was no statistically significant correlation between soil bacterial diversity and total organic carbon （TOC）, total nitrogen, or total phosphorus contents of the soil. Canonical correlation analysis showed that TOC content was the most important factor determining bacterial community profiles among the measured soil parameters. In conclusion, microbial biodiversity and community characteristics within relatively small scales （1.5 km） were determined as a function of local environment parameters and anthropogenic impact.

关键词： Antarctica 16S rRNA gene denaturing gradient gel electrophoresis human impact

Forest fragmentation and human population varies logarithmically along elevation gradient in Hindu Kush Himalaya-utility of geospatial tools and free data set

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Journal of Mountain Science 2017年第12期14卷 2432-2447页

作者： DAS Pulakesh BEHERA Mukunda Dev MURTHY Manchiraju Sri Ramachandra Centre for Ocean River Atmosphere and Land Sciences Indian Institute of Technology Kharagpur International Centre for Integrated Mountain Development (ICIMOD)

Hindu Kush Himalaya(HKH) is the largest and the most diverse mountain region in the world that provides ecosystem services to one fifth of the total world population. The forests are fragmented to different degrees due to expansion and intensification of human land use. However, the quantitative relationship between fragmentation and demography has not been established before for HKH vis-à-vis along elevation gradient. We used the globally available tree canopy cover data derived from Landsat-TM satellite to find out the decadal forest cover change over 2000 to 2010 and their corresponding fragmentation levels. Using SRTMderived DEM, we observed high forest cover loss up to2400 m that highly corroborated with the population distribution pattern as derived from satellite observation. In general, forest cover loss was found to be higher in south-eastern part of HKH. Forest fragmentation obtained using ‘area-weighted mean radius of gyration' as indicator, was found to be very high up to 2400 m that also corroborated with high human population for the year 2000 and 2010. We observed logarithmic decrease in fragmentation change(area-weighted mean radius of gyration value),forest cover loss and population growth during 2000-2010 along the elevation gradient with very high R^2 values(i.e., 0.889, 0.895, 0.944 respectively). Our finding on the pattern of forest fragmentation and human population across the elevation gradient in HKH region will have policy level implication for different nations and would help in characterizing hotspots of change. Availability of free satellite derived data products on forest cover and DEM, griddata on demography, and utility of geospatial tools helped in quick evaluation of the forest fragmentation vis-a-vis human impact pattern along the elevation gradient in HKH.

关键词： Tree canopy cover Topography Diachronic analysis Biogeography human impact

Petrography of alluvial sands as a past and present environmental indicator:Case of the Loire River(France)

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International Journal of Sediment Research 2013年第3期28卷 285-303页

作者： Jean-Jacques MACAIRE Isabelle GAY-OVEJERO Michel BACCHI Constantin COCIRTA Luc PATRYL Stéphane RODRIGUES University Franqois-Rabelais of Tours University Francois-Rabelais of Tours SARL RIVE 4. Commissariat a l'Energie Atomique-CEA DAMDIF

Four sample sets of the Upper and Middle Loire river sands were analyzed in order to study the impact of natural and anthropogenic factors on their petrographic composition in space(on an 800 km stretch) and *** was determined by modal analysis of three sand-size fractions using a polarizing optical microscope and calculated for each sample("standard sand" = Sst).The watershed is composed mainly of endogenic(Massif Central) and sedimentary(southern Parisian Basin) rocks.B-set sands collected in channels for different water flows in 1996 show that Sst compositions vary by only 5%.Present-day sands in the Upper Loire and Middle Loire have very high petrographic immaturity comparing to others worldwide fluvial sands,although bio-climatic conditions favor sand maturation by source-rock weathering in the *** shows the strong impact of the Massif Central on sediment yield due to relief rejuvenation as a consequence of the formation of the Alps during the *** sands stored during the Weichselian and the Holocene in the Middle Loire floodplain,although partly weathered since their deposition,show higher inputs from the endogenic rocks of the Massif Central than present-day *** can be explained by Weichselian periglacial conditions and the development of crop farming since the Neolithic,which favored mechanical erosion,particularly in the Massif Central which is characterized by a cold,humid climate and steep *** upstream-downstream change in the composition of presently deposited sand is low in the diked *** shows however that basalt and some heavy mineral grains are vulnerable to abrasion during transport and indicates a marked sediment yield from ancient sediment stored in the *** is in line with the high incision of the river bed over the last 150 years partly due to dam construction and aggregate mining.

关键词： Fluvial sand Sand petrography Sediment source Tectonics impact human impact Loire river

Rainfall patterns of Algerian steppes and the impacts on natural vegetation in the 20^th century

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Journal of Arid Land 2018年第4期10卷 561-573页

作者： Fahima BELALA Azziz HIRCHE Serge D MULLER Mahmoud TOURKI Mostefa SALAMANI Mohamed GRANDI TaharAIT HAMOUDA Madjid BOUGHANI Laboratory of Plant Ecology Faculty of Biological SciencesUniversity of Sciences and Technology Houari BoumedieneWilaya 16000Algeria Scientific and Technical Research Center on Arid Regions Biskra 7000Algeria Institute of Evolutionary Sciences University of Montpellier-CNRSMontpellier 34095France Department of Hydraulics University of Badji MokhtarAnnaba 23000Algeria Faculty of Nature Sciences University of Saad DahlabBlida 9000Algeria Faculty of Sciences University of Yahia FaresWilaya 26000Algeria

Since 1960, the steppe regions of North Africa have been subject to an increasing desertification, including the degradation of traditional pastures. The initially dominant species （Artemisia herba-alba, Lygeum spartum and Slipa tenacissima） declined and were progressively replaced by other species （Atractylis serratuloides and Salsola vermiculata） that are more tolerant to the new conditions. It is not clear whether these changes are due to anthropogenic reasons or climatic determinism. We have carried out a statistical analysis of the climate to detect putative rainfall changes during the 20th century in the Algerian steppes based on data from 9 meteorological stations, including 2 Saharan stations （El Oued and Touggourt）, 3 pre-Saharan stations （Biskra, Laghouat and Ain Sefra） and 4 steppe stations （Djelfa, Saida, M6ch6ria and E1-Bayadh） located in the arid high plains, which represent the bioclimate diversities of the region. Previous studies suggested that significant rainfall changes for the 20th century only had records in the south of the Oran region. Most of the studies, however, looked at restricted territories over limited periods, and did not integrate the rainiest period 2004-2014. Our work is designed to integrate all the longest time series of meteorological data available for the steppe regions of Algeria. Our results confirm the spatial rainfall distribution （significant rainfall changes only recorded in the southwestern region） evidenced by previous studies, and reveal a decreasing rainfall gradient from northeastern to southwestern Algeria. Moreover, the results reveal a trend of significant decrease of rainfall in the southern Oran region, marked by two drought periods in 1980- 1985 and 1999-2003. However, with the exception of the southwestern region, rainfall overall has not declined since the beginning of the 20th century. While less marked in other regions, the drought appear to have affected all territories of the Algerian steppe. Consequent

关键词： climate arid and semi-arid regions drought rangeland degradation human impact North Africa

Age Structure and Growth of Degraded Populus euphratica Floodplain Forests in North-west China and Perspectives for Their Recovery

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Journal of Integrative Plant Biology 2008年第5期50卷 536-546页

作者： Janneke Westermann Stefan Zerbe Dieter Eckstein Technical University of Berlin Institute of EcologyRothenburgstraβe 12D-12165 BerlinGermany University of Greifswald Institute of Botany and Landscape EcologyGrimmer Straβe 88D-17487 GreifswaldGermany University of Hamburg Department of Wood ScienceDivision of Wood BiologyLeuschnerstraβe 91D-21031 HamburgGermany

The Populus euphratica floodplain forests along the lower reaches of the Tarim River in continental-arid Xinjiang （northwest China） have been declining in recent decades as a result of dam constructions and the withdrawal of water from the river. Since 2000, controlled flooding has been carried out to counteract this process of degradation. However, the consequences of a changing water regime for the floodplain ecosystem are not yet sufficiently investigated. In 2004 we sampled a total of 150 P. euphratica trees along two transects at the middle and lower reaches of the Tarim River to compare the age structure and growth of these two tree populations. The anthropogenic drawdown of the groundwater table had no effect on the average growth of the trees at the lower reaches. However, tree growth abruptly increased after controlled flooding, thus showing distinct signs of recovery.

关键词： arid land controlled flooding Euphrates poplar human impact Populus euphratica tree rings.

human-driven topographic effects on the distribution of forest in a flat, lowland agricultural region

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Journal of Geographical Sciences 2014年第1期24卷 76-92页

作者： Mette V. ODGAARD Peder K. BOCHER Tommy DALGAARD Jesper E. MOESLUND Jens-Christian SVENNING Department of Agroecology Aarhus University Blichers AIIe 20 DK-8830 Tjele Denmark Ecoinformatics & Biodiversity Group Department of Bioscience Aarhus University Ny Munkegade 114DK-8000 Aarhus C Denmark Department of Computer Science Aarhus University Abogade 34 DK-8200 Aarhus N Denmark

Complex topography buffers forests against deforestation in mountainous regions. However, it is unknown if terrain also shapes forest distribution in lowlands where human impacts are likely to be less constrained by terrain. In such regions, if important at all, to- pographic effects will depend on cultural-historical factors and thus be human-driven （an- thropogenic） rather than natural, except in regions where the general climate or extreme soils limit the occurrence of forests. We used spatial regression modeling to assess the extent to which topographic factors explain forest distribution （presence-absence at a 48x48 m resolu- tion） in a lowland agricultural region （Denmark, 43,075 km2） at regional and landscape scales （whole study area and 10x10 km grid cells, respectively）, how landscape-scale for- est-topography relationships vary geographically, and which potential drivers （topographic heterogeneity, forest cover, clay content, coastal/inland location） determine this geographic heterogeneity. Given a moist temperate climate and non-extreme soils all landscapes in Denmark would naturally be largely forest covered, and any topographic relationships will be totally or primarily human-driven. At regional scale, topographic predictors explained only 5% of the distribution of forest. In contrast, the explanatory power of topography varied from 0%-61% at landscape scale, with clear geographic patterning. Explanatory power of topog- raphy at landscape scale was moderately dependent on the potential drivers, with topog- raphic control being strongest in areas with high topographic heterogeneity and little forest cover. However, these conditioning effects were themselves geographically variable. Our findings show that topography by shaping human land-use can affect forest distribution even in flat, lowland regions, but especially via localized, geographically variable effects.

关键词： Europe forest cover geographically weighted regression human impact landscape development topography vegetation distribution.

human’s digital footprints on the Qinghai-Tibet Plateau:Variations during festivals and impacts on nature reserves

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Journal of Geographical Sciences 2021年第2期31卷 179-194页

作者： DU Yunyan TU Wenna LIANG Fuyuan YI Jiawei State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Department of Earth Atmosphericand Geographic Information SciencesWestern Illinois UniversityMacombIL61455USA

Mobile internet and wireless communication technologies have produced unprecedented location-aware *** big geospatial data can be used as a proxy measure of the‘digital footprints’left by us on the planet and provide a valuable opportunity to understand the dynamic and short-term human disturbance on the nature at fine *** study investigated the spatiotemporal variations of human’s digital footprints on the Qinghai-Tibet Plateau using smartphone-users-generated Tencent’s location request *** results showed that human’s digital footprints cover less than 5%of Qinghai and Tibet,exhibiting either a U-shaped or an N-shaped temporal change pattern during the major *** changes of the digital footprints manifested a transition process from dispersion to concentration in Xining and *** disturbance assessment of seven large nature reserves on the plateau showed that the Qinghai Lake is the most disturbed one as shown by 14.6%of its area is stained with human digital footprints and the areal average of footprint intensity is 1.59,and the disturbance was significantly escalated during the National Day *** contrast,the Qangtang and Hoh Xil are the least affected nature reserves with the two indices less than 1%and 0.1,respectively.

关键词： digital footprint space-time variations human impact nature reserve location request