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1

A new model for hazard evaluation of vegetation degradation using DPSIR framework, a case study: Sadra Region, Iran

100%
Masoudi M., Amiri E.
Polish Journal of Ecology
|
2015
|
tom 63
|
nr 1
Vegetation degradation causes reduction in the available biomass, and decline in the vegetative cover. The Sadra watershed which covers the upper reaches of Marharlu basin, in southern Iran, has been chosen for a test hazard assessment of this type of degradation. The different kinds of data for indicators of vegetation degradation were gathered from collecting of field data like percent canopy and biomass and also records and published reports of the governmental offices of Iran. A new model has been developed for assessing the hazard of vegetation degradation using DPSIR (Driving forces, Pressures, State, Impacts and Responses) framework. The approach is based on the use of indicators, which may be direct or indirect, ecological, technical, socioeconomic or cultural causes of environmental hazard. Taking into consideration fourteen indicators of vegetation degradation the model identifies areas with different hazard class. The preparation of hazard maps based on the Geographic Information System (GIS) analysis of these indicators will be helpful for prioritizing the areas to initiate remedial measures. By fixing the thresholds of severity classes of the fourteen indicators, a hazard map for each indicator was first prepared in GIS. The hazard classes were defined on the basis of hazard scores arrived at by assigning the appropriate attributes to the indicators and the final hazard map was prepared by intersecting fourteen hazard maps in five main hazard layers including anthropogenic, natural, current state of hazard, livestock pressure and trend of degradation in the GIS. Results show among the five main hazard maps used in the model, the most main effective indicator in vegetation degradation of the study area is ‘Current State of Hazard’. Also areas under severe hazard class have been found to be widespread (58%) and areas under moderate hazard class have been found (42%) in the Sadra watershed.
2

Decomposition processes in coastal wetlands: the importance of Suaeda salsa community for soil cellulose decomposition

84%
Ping Y., Cui L., Pan X., Li W., Li Y., Kang X., Song T., He P.
Polish Journal of Ecology
|
2018
|
tom 66
|
nr 3
Coastal wetlands are ecologically important all over the world, and they are relatively unstable with dramatic changes in aboveground vegetation. However, it is still unclear how the aboveground vegetation changes will influence the functioning of coastal wetland ecosystems, especially the decomposition processes. Here, we carried out a cotton strip experiment to examine the effects of Suaeda salsa community on the soil properties and the associated cellulose decomposition rates in the coastal wetlands of Liao River delta (NE China). Our results showed that S. salsa community significantly affected the contents of soil C, N, P, base cations, organic matter and the soil electrical conductivity (EC), and such effects might vary among different types or densities of aboveground vegetation. The soil cellulose decomposition rate (in terms of cotton strip tensile strength loss, CTSL) was slowed down when aboveground S. salsa communities are experiencing degradation or have been totally replaced by Phragmites australis communities. Moreover, there were positive partial correlations between soil N and CTSL, and between soil EC and CTSL, but a negative partial correlation between soil C and CTSL. Our results emphasized the importance of S. salsa community in determining the soil cellulose decomposition rate in this coastal region. The results suggest that vegetation degradation in coastal wetlands might lead to various changes in soil properties and hence affect other aspects of ecosystem functioning and services, especially nutrient cycling.
3

Ramet recruitment from different bud types along a grassland degradation gradient in Inner Mongolia, China

84%
Qian J., Busso C. A., Wang Z., Liu Z.
Polish Journal of Ecology
|
2015
|
tom 63
|
nr 1
Since the contribution of total belowground bud bank and different bud types to community regeneration has rarely been explored, the vegetative offspring recruited from different belowground bud types was investigated in four plant communities along a grassland degradation gradient in northeastern China (Inner Mongolia). This gradient, between 1000 and 1500 m a.s.l., has been caused by overgrazing. It is a Leymus chinensis steppe which occupies about 3.0×10⁵ ha. Recruitment from tiller buds was dominant (>80%) in determining the total vegetative offspring density along the whole grassland degradation gradient. However, the proportional contribution of tiller-ramets to total ramet recruitment was significantly greater (P <0.05) during earlier than later stages of grassland degradation, while that of rhizome-ramets showed an opposite pattern. While the percentage contribution and density of root-derived ramets to total ramet density increased significantly (P <0.05) during the late stages of grassland degradation, those of bulb-ramets kept relatively constant along the whole grassland degradation gradient. The relative contribution of hemicryptophytes [i.e., Achnatherum sibiricum, Cleistogenes squarrosa, Festuca ovina, Koeoleria cristata, Poa annua, Stipa grandis] to total plant species richness decreased, while that of geophytes [i.e., Agropyron cristatum, Carex korshinskyi. Leymus chinensis, Allium anisopodium, A. bidentatum, A. tenuissimum, Astragalus galactites, Cymbaria dahurica, Iris tenuifolin, Potentilla acaulis, P. bifurca, Pulsatilla turczaninovii, Serratula chinensis, Thalictrum aquilegifolium] increased with the increases of grassland degradation. Our results showed that as grassland degradation increased, changes in the proportion of tiller-, rhizome- and root-derived ramets with respect to total ramet density determined in turn changes in the proportion of hemicryptophytes and geophytes in the study plant communities.
4

Irreversible microevolutionary changes in genotypic composition of sika deer Cervus nippon populations in response to vegetation degradation and food shortage

67%
Sheremetev I., Sheremeteva I.
Acta Theriologica
|
2010
|
tom 55
|
nr 1
9-26
The present study deals with changes in important skull characteristics of the sika deer Cervus nippon Temminck, 1838 in response to changes in food supply. Moderate food shortage results mainly in a linear reduction in skull size, while severe food shortage results in changes in skull shape. In the deer that returned to habitats with sufficient food supply, some skull parameters recovered to, or even exceeded, normal values, whereas other parameters remained stressed resulting in retention or enhancement of skull distortions. Differences in skull parameters among the populations studied were comparable to those between some cervid species, eg, the Siberian roe deer Capreolus pigargus Pallas, 1771 and European roe deer Capreolus capreolus Linnaeus, 1758 and other deer subspecies. In the introduced sika deer populations, skull distortions were apparently caused by interspecific hybridization. Descendants of the escaped deer have not reverted to the normal phenotype, even over several generations, providing a recent case of true evolutionary changes. This occurred by a change in the ratio of different morphotypical groups, probably due to their different responses to food shortage. Thus sufficient food supply may account for changes in a population’s genotypic composition through selection of characteristics that favour passing on genetic material when food is limited.
5

A new model for desertification assessment using Geographic Information System (GIS) − a case study, Runiz Basin, Iran

67%
Masoudi M., Jokar P.
Polish Journal of Ecology
|
2017
|
tom 65
|
nr 2
The present paper attempts to evolve a new model by considering various indicators of different types of land degradation or desertification, namely, water erosion, soil salinity, vegetation degradation, and lowering of ground water table for finding areas with higher rate of degradation. The Runiz basin, located in the southern Iran, has been selected as a study area to assess the hazard of desertification. The thresholds for the severity classes of indicators were established and then the hazard map for each indicator of types of desertification has been prepared in a GIS. The risk classes of different risk maps were calculated on the basis of classification of risk scores derived by cumulative effect of all the attributes of indicators after overlying them in the GIS. It was possible to distinguish the areas under ‘actual risk’ from areas under ‘potential risk’ of desertification types. Also areas under potential risk were classified to subclasses with different probability level to show a statistical picture of risk in future. The final map of risk of desertification was produced by overlaying all four maps of degradation types. Results show that potential risk areas and areas under actual risk are almost equal, indicating further threat of desertification in future in the half of the region. Also severe condition in the half of region shows environmentally bad situation in the study area. It is hoped that this attempt using GIS will be found applicable for other regions of the world.
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