We examined the local community incentive programs to improve traditional forest management in three forested villages in Baneh city, Kurdistan province in the northern Zagros forests of western Iran. Zagros forests c...We examined the local community incentive programs to improve traditional forest management in three forested villages in Baneh city, Kurdistan province in the northern Zagros forests of western Iran. Zagros forests cover 6.07 million ha and support rich plant and animal diversity. Changes in local community social and economic sys-tems and the inefficiency of traditional forest management led to a criti-cal situation in the stability of forest regeneration in recent decades. Due to a shortage of productive and arable lands and resulting unemployment and poverty, people overexploited the Zagros forests. Outside interven-tion in traditional forest management creates conflicts between local peoples and forest management organizations. To achieve sustainable forest management, including forest resources conservation and im-provement of natural resource based livelihoods of communities, it is desirable to implement Forestry Incentive Programs （FIP） based on the important functions of forests. Detailed information on the so-cio-economics of communities, the effect of forests on local livelihoods, and lists of products extracted from the forest were obtained from a sur-vey of local communities though questionnaire, interview and observa-tion. We studied 276 households in three villages and completed 76 ques-tionnaires by householders in the quantitative analysis. Sampling was performed by simple random sampling （SRS）. The needs of rural com-munities, such as livestock husbandry, mainly arise from the characteris-tics and environmental features of villages. We identified the driving forces, pressures, status, impacts and responses （DPSIR） to design incen-tive programs, by DPSIR analysis and interaction analysis. Evaluation of local community benefits from forests showed that in order to improve forest management, 319 dollars per year would be needed by each family as an incentive in 2010 to prevent lopping and firewood collecting, the main causes of forest degradation.展开更多
In this study, for accuracy and cost an optimal inventory method was examined and introduced to obtain information about Zagros forests, Iran. For this purpose,three distance sampling methods(compound, order distance ...In this study, for accuracy and cost an optimal inventory method was examined and introduced to obtain information about Zagros forests, Iran. For this purpose,three distance sampling methods(compound, order distance and random-pairs) in 5 inventory networks(100 m × 100 m, 100 m × 150 m, 100 m × 200 m,150 m × 150 m, 200 m × 200 m) were implemented in GIS environment, and the related statistical analyses were carried out. Average tree density and canopy cover in hectare with 100% inventory were compared to each other.All the studied methods were implemented in 30 inventory points, and the implementation time of each was recorded.According to the results, the best inventory methods for estimating density and canopy cover were compound150 m × 150 m and 100 m × 100 m methods, respectively. The minimum amount of product inventory time per second(T), and(E%)2 square percent of inventory error of sampling for the compound 150 m × 150 m method regarding density in hectare was 691.8, and for the compound 100 m × 100 m method regarding canopy of 12,089 ha. It can be concluded that compound method is the best for estimating density and canopy features of the forests area.展开更多
Persian oak(Quercus brantii var.persica)is a dominant tree species of Zagros forests in a semi-arid area,western Iran.However,the capacity of biomass and carbon stocks of these forests is not well studied.We selected ...Persian oak(Quercus brantii var.persica)is a dominant tree species of Zagros forests in a semi-arid area,western Iran.However,the capacity of biomass and carbon stocks of these forests is not well studied.We selected three types of oak,i.e.,seed-originated oak,coppice oak and mixed(seed-originated and coppice)oak of Zagros forests in Dalab valley,Ilam Province,Iran to survey the capacity of biomass and carbon stocks in 2018.Thirty plots with an area of 1000 m2 were systematically and randomly assigned to each type of oak.Quantitative characteristics of trees,such as diameter at breast height(DBH),height,crown diameter and the number of sprouts in each plot were measured.Then,aboveground biomass(AGB),belowground biomass(BGB),aboveground carbon stock(AGCS)and belowground carbon stock(BGCS)of each tree in plots were calculated using allometric equations.The litterfall biomass(LFB)and litterfall carbon stock(LFCS)were measured in a quadrat with 1 m×1 m in each plot.One-way analysis of variance and Duncan's test were performed to detect the differences in biomass and carbon stocks among three types of oak.Results showed that AGB,BGB and BGCS were significantly different among three types of oak.The highest values of AGB,AGCS,BGB and BGCS in seed-originated oak were 76,043.25,14,725.55,36,737.79 and 7362.77 kg/hm2,respectively.Also,the highest values of LFB and LFCS in seed-originated oak were 3298.33 and 1520.48 kg/hm2,respectively,which were significantly higher than those of the other two types of oak.The results imply the significant role of seed-originated oak for the regeneration of Zagros forests.Further conservation strategy of seed-originated oak is an important step in the sustainable management of Zagros forests in Iran.展开更多
Arbuscular mycorrhizal fungi(AMF)play a vital role in plant productivity and ecosystem functions.However,their responses to abiotic factors(i.e.,climate,physiography,and soil properties)are unknown,especially across c...Arbuscular mycorrhizal fungi(AMF)play a vital role in plant productivity and ecosystem functions.However,their responses to abiotic factors(i.e.,climate,physiography,and soil properties)are unknown,especially across climatic gradients and slope aspects in arid and semi-arid ecosys-tems.In this study,using 60 composite soil samples,direct and indirect effects of climate factors and slope aspects on AMF diversity,composition and spore density were studied.The findings indicate that climate has a more direct influ-ence on soil properties(P<0.001)in comparison to slope aspect(P=0.449).In contrast,climate significantly affected AMF diversity and composition,with the highest diversity in dryer areas.Soil pH had the highest correlation with different facets of AMF diversity.Structural equation modeling(SEM)indicated that only a small part of the variation in AMF diversity and spore density could be explained by climate characteristics,slope aspect and soil properties.Based on SEM results,climate was the most important determinant of AMF diversity and spore density;slope aspect had a less critical role.The outputs suggest that variations in AMF diversity are derived by the direct effects of climate and the indirect effect of soil chemical properties.In addition,with increasing dryness,sporulation and AMF diversity increased.展开更多
Zagros forests are mainly covered byQuercus brantii L. coppices and oak sprout clumps occupy the forest area like patches. We investigated post-fire herbaceous diversity in the first growing season after fire. For thi...Zagros forests are mainly covered byQuercus brantii L. coppices and oak sprout clumps occupy the forest area like patches. We investigated post-fire herbaceous diversity in the first growing season after fire. For this purpose neighboring burned and unburned areas were selected with the same plant species and ecological conditions. The data were collected from areas subjected to different fire severities. Overall 6 treatments were considered with respect to fire severity and the mi-crosites of inside and outside of oak sprout clumps including： unburned inside and outside of sprout clumps （Ni and No）, inside of sprout clumps that burned with high fire severity （H）, inside of sprout clumps that burned with moderate fire severity （M）, outside of sprout clumps that burned with low fire severity （OH and OM）. Different herbaceous com-position was observed in the unburned inside and outside of oak sprout clumps. The species diversity and richness were increased in treatments burned with low and moderate fire severity. However, in treatment burned with high fire severity （H）, herbaceous cover was reduced, even-ness was increased, and richness and diversity were not significantly changed. We concluded that besides the microsites conditions in forest, fire severity is an inseparable part of the ecological effect of fire on her-baceous composition.展开更多
The response of diversity and biomass of herbaceous functional groups along an altitudinal gradient in mountainous forests of southern Zagros,Khuzestan Province,Iran was studied by sampling vegetation in 30 circular 1...The response of diversity and biomass of herbaceous functional groups along an altitudinal gradient in mountainous forests of southern Zagros,Khuzestan Province,Iran was studied by sampling vegetation in 30 circular 1000-m^2 plots in herb layer of the forest floor within 646–2447 m asl(lowland:<1000 m asl,midland:1000–2000 m asl,highland:>2000 m asl).The most important herbaceous functional groups were classified based on two aspects of growth form:annuals–perennials,grasses–forbs.Then the relationship between the diversity,richness,evenness,biomass and elevation was analyzed.The results showed that the annual functional group in the low-and midland classes,and perennial functional group in the lowland class had the highest species diversity and evenness in annual and perennial functional groups,respectively(p<0.01).The perennials in the highland class had the maximum total,above-and belowground dry biomass(p<0.01).On the other hand,the forb functional group in the lowland class had the greatest species diversity,richness,and evenness(p<0.01)and in the highland class had the maximum total dry,above-and belowground dry biomass in the grass and forb functional groups(p<0.01).Increasing the diversity,richness,and species evenness resulted in a decrease in the plant dry biomass.展开更多
The consequence of land-use change from forest to agriculture and other uses has become one of the world’s greatest concerns.The soil,one of the most important components of forests and containing all the required pl...The consequence of land-use change from forest to agriculture and other uses has become one of the world’s greatest concerns.The soil,one of the most important components of forests and containing all the required plant nutrients as soluble ions,is highly impacted by these changes.Because vast areas of the Zagros forests in western Iran have changed in use during the last few decades,the present study investigated the effects of landuse changes of forest area to agriculture,orchard,and agroforestry on soil chemical and physical properties.Soil was sampled at four land-use areas:less-disturbed forest areas(control)and agricultural,orchard,and agroforestry areas.Among each of the two forest-use areas(agroforestry and orchard),we selected five trees with similar-sized crowns and sampled under each tree crown at 0-15 and>15-30 cm depths.Five soil samples also were taken in agriculture area at each depth.The findings indicated that during land-use changes,soil sand particles decreased,and clay and silt particles of soil increased,resulting in a fine soil texture.Moreover,the amount of nitrogen(N),phosphorus(P),organic carbon(OC),and electrical conductivity(EC)of soil decreased at both depths due to the decrease in organic matter.Soil pH and magnesium(Mg)level rose during land-use change at both depths except at agricultural sites.Soil potassium(K)content decreased during agricultural use due to the elimination of tree cover.The level of K decreased only at the depth of 0-15 cm because of K dependency on parent materials.Generally,most soil nutrients were affected by plant removal in the conversion.Forest and agricultural soil are distinguishable by their properties,while land-uses such as agroforestry-orchard separated from the others.Soil nutrients were severely affected by the decrease and elimination of tree cover,plowing,and continuous harvesting,resulting in a decline in soil quality and fertility.展开更多
The main aim of this study was to evaluate methods for fixed area and distance sampling in the Zagros open forest area in western Iran. Basic forest management and planning required appropriate quantitative and qualit...The main aim of this study was to evaluate methods for fixed area and distance sampling in the Zagros open forest area in western Iran. Basic forest management and planning required appropriate quantitative and qualitative information. Two sampling methods were compared on the basis of the actual means of characteristics derived from the 100 % survey. In total, 37 sampling plots were systematically installed with a grid of 100 m × 100 m in the study area. Density, crown canopy, and basal area of the stands were measured. The 100 % survey showed that tree density above 12.5 cm diameter at breast height was 68.04 stem ha-1, basal area was 15.16 m2 ha-1 and crown canopy percentage was 35.71% ha-1. The values for the traits determined by the two sampling methods differed significantly （P = 0.05）. When the time required for the methods was compared, transect sampling required less than systematic-random sampling. Therefore, the transect sampling method was the more economical method for the Zagros open forests. The transect sampling method was statistically defensible and practical for quantitating characteristics of the Zagros open forests.展开更多
The status of woody plants in dry-land systems is a fundamental determinant of key ecosystem processes. Monitoring of this status plays an important role in understanding the dynamics of woody plants in arid and semi-...The status of woody plants in dry-land systems is a fundamental determinant of key ecosystem processes. Monitoring of this status plays an important role in understanding the dynamics of woody plants in arid and semi-arid ecosystems. The present study determined the dynamism of the Zagros forests in Iran using Remote Sensing and Geographic Information System techniques and statistical science. The results show that the density of trees varied from 10 to 53 % according to the physio- graphic and climatic conditions of semi-arid regions. The best and lowest correlation between vegetation indices and forest density were obtained for the global environmental monitoring index （GEMI; R2 = 0.94） and soil adjust vegetation index （R2 = 0.81）, respectively. GEMI is used to monitor land use changes over a 10-year period. Results show that 2720 ha2 of forest have been destroyed by human interference and tillage on steep slopes during this period which also resulted in the loss of the fertile soil layer. GEMI determined the areas with a biomass of trees and could normally separate border regions with low bio- mass density of trees from regions without canopy cover. The results revealed that assessment of forest and vegetation cover in arid and semi-arid arduous forest regions using satellite digital numbers and ordinary sampling is subject to uncertainty. A stratified grouping procedure should be established to increase the accuracy of assessment.展开更多
The Zagros forests are a treasure of valuable oak forests, but they have been severely degraded from long-term misuse. Geographic information systems （GIS） and multi-criteria decision analysis （MCDA） have been inc...The Zagros forests are a treasure of valuable oak forests, but they have been severely degraded from long-term misuse. Geographic information systems （GIS） and multi-criteria decision analysis （MCDA） have been increasingly used to improve the management of vulnerable ecosystems to prevent further degradation and increase the sustainability of land use. This study presents a methodology to assess land suitability using remote sensing （RS） to obtain wall-to-wall data for the calculations, GIS to analyze the data, and MCDA to rank alternative land uses. The criteria and subcriteria affecting the suitability of land for different uses were identified and weighted using an analytic hierarchy process. Variables used as subcriteria were assessed using satellite data and other sources of information such as existing maps and field surveys. Numerical values for the subcriteria were classified, and each class was given a priority rating according to expert judgments. Based on the ratings and weights of the subcriteria, a priority map was created for each land use using the weighted linear combination method. The priority maps for different land uses were overlaid to obtain a preliminary land use map, which often indicated several simultaneous land uses for the same location. The preliminary map was further edited by removing unrealistic, mutually exclusive land-use combinations. The study tested and demonstrated the potential of integrating RS, G1S and MCDA techniques for solving complicated land allocation problems in forested regions using a scientifically sound and practical approach for efficient and sustainable allocation of forestland for different uses.展开更多
Forest edges have been well studied in temperate and tropical forests,but less so in open canopy forests.We investigated edge influence on plant species diversity and soil properties in sparse oak forest fragments.Dat...Forest edges have been well studied in temperate and tropical forests,but less so in open canopy forests.We investigated edge influence on plant species diversity and soil properties in sparse oak forest fragments.Data were collected along three transects from the edge to the interior of three small(under 10 ha)and three large(over 10 ha)oak forest fragments in Kermanshah Province,Iran.We measured herbaceous plants(<0.5 m in height)and soil attributes at 0(forest edge),25,50,100 and 150 m.We quantified species diversity using the Shannon index,used rarefaction to compare species richness between two different sizes of fragments and applied non-metric multidimensional scaling ordination to investigate the variation in species composition.We estimated the distance of edge influence using randomization tests.Generalized linear mixed models with post-hoc Tukey’s HSD tests were used to assess the effects of distance from edge and fragment size on diversity and soil properties.We found greater species richness,diversity and evenness at the edge of both small and large fragments and lower nitrogen and organic carbon at the edge compared to the interior of large fragments,with most changes within 50 m of the edge.Species composition,organic carbon and total nitrogen were significantly different between small and large fragments.Our findings of significant edge influence on herbaceous plants and soil properties in these sparse forests provide a significant contribution to the literature on edges,especially in relation to herbaceous plants.展开更多
文摘We examined the local community incentive programs to improve traditional forest management in three forested villages in Baneh city, Kurdistan province in the northern Zagros forests of western Iran. Zagros forests cover 6.07 million ha and support rich plant and animal diversity. Changes in local community social and economic sys-tems and the inefficiency of traditional forest management led to a criti-cal situation in the stability of forest regeneration in recent decades. Due to a shortage of productive and arable lands and resulting unemployment and poverty, people overexploited the Zagros forests. Outside interven-tion in traditional forest management creates conflicts between local peoples and forest management organizations. To achieve sustainable forest management, including forest resources conservation and im-provement of natural resource based livelihoods of communities, it is desirable to implement Forestry Incentive Programs （FIP） based on the important functions of forests. Detailed information on the so-cio-economics of communities, the effect of forests on local livelihoods, and lists of products extracted from the forest were obtained from a sur-vey of local communities though questionnaire, interview and observa-tion. We studied 276 households in three villages and completed 76 ques-tionnaires by householders in the quantitative analysis. Sampling was performed by simple random sampling （SRS）. The needs of rural com-munities, such as livestock husbandry, mainly arise from the characteris-tics and environmental features of villages. We identified the driving forces, pressures, status, impacts and responses （DPSIR） to design incen-tive programs, by DPSIR analysis and interaction analysis. Evaluation of local community benefits from forests showed that in order to improve forest management, 319 dollars per year would be needed by each family as an incentive in 2010 to prevent lopping and firewood collecting, the main causes of forest degradation.
文摘In this study, for accuracy and cost an optimal inventory method was examined and introduced to obtain information about Zagros forests, Iran. For this purpose,three distance sampling methods(compound, order distance and random-pairs) in 5 inventory networks(100 m × 100 m, 100 m × 150 m, 100 m × 200 m,150 m × 150 m, 200 m × 200 m) were implemented in GIS environment, and the related statistical analyses were carried out. Average tree density and canopy cover in hectare with 100% inventory were compared to each other.All the studied methods were implemented in 30 inventory points, and the implementation time of each was recorded.According to the results, the best inventory methods for estimating density and canopy cover were compound150 m × 150 m and 100 m × 100 m methods, respectively. The minimum amount of product inventory time per second(T), and(E%)2 square percent of inventory error of sampling for the compound 150 m × 150 m method regarding density in hectare was 691.8, and for the compound 100 m × 100 m method regarding canopy of 12,089 ha. It can be concluded that compound method is the best for estimating density and canopy features of the forests area.
文摘Persian oak(Quercus brantii var.persica)is a dominant tree species of Zagros forests in a semi-arid area,western Iran.However,the capacity of biomass and carbon stocks of these forests is not well studied.We selected three types of oak,i.e.,seed-originated oak,coppice oak and mixed(seed-originated and coppice)oak of Zagros forests in Dalab valley,Ilam Province,Iran to survey the capacity of biomass and carbon stocks in 2018.Thirty plots with an area of 1000 m2 were systematically and randomly assigned to each type of oak.Quantitative characteristics of trees,such as diameter at breast height(DBH),height,crown diameter and the number of sprouts in each plot were measured.Then,aboveground biomass(AGB),belowground biomass(BGB),aboveground carbon stock(AGCS)and belowground carbon stock(BGCS)of each tree in plots were calculated using allometric equations.The litterfall biomass(LFB)and litterfall carbon stock(LFCS)were measured in a quadrat with 1 m×1 m in each plot.One-way analysis of variance and Duncan's test were performed to detect the differences in biomass and carbon stocks among three types of oak.Results showed that AGB,BGB and BGCS were significantly different among three types of oak.The highest values of AGB,AGCS,BGB and BGCS in seed-originated oak were 76,043.25,14,725.55,36,737.79 and 7362.77 kg/hm2,respectively.Also,the highest values of LFB and LFCS in seed-originated oak were 3298.33 and 1520.48 kg/hm2,respectively,which were significantly higher than those of the other two types of oak.The results imply the significant role of seed-originated oak for the regeneration of Zagros forests.Further conservation strategy of seed-originated oak is an important step in the sustainable management of Zagros forests in Iran.
文摘Arbuscular mycorrhizal fungi(AMF)play a vital role in plant productivity and ecosystem functions.However,their responses to abiotic factors(i.e.,climate,physiography,and soil properties)are unknown,especially across climatic gradients and slope aspects in arid and semi-arid ecosys-tems.In this study,using 60 composite soil samples,direct and indirect effects of climate factors and slope aspects on AMF diversity,composition and spore density were studied.The findings indicate that climate has a more direct influ-ence on soil properties(P<0.001)in comparison to slope aspect(P=0.449).In contrast,climate significantly affected AMF diversity and composition,with the highest diversity in dryer areas.Soil pH had the highest correlation with different facets of AMF diversity.Structural equation modeling(SEM)indicated that only a small part of the variation in AMF diversity and spore density could be explained by climate characteristics,slope aspect and soil properties.Based on SEM results,climate was the most important determinant of AMF diversity and spore density;slope aspect had a less critical role.The outputs suggest that variations in AMF diversity are derived by the direct effects of climate and the indirect effect of soil chemical properties.In addition,with increasing dryness,sporulation and AMF diversity increased.
文摘Zagros forests are mainly covered byQuercus brantii L. coppices and oak sprout clumps occupy the forest area like patches. We investigated post-fire herbaceous diversity in the first growing season after fire. For this purpose neighboring burned and unburned areas were selected with the same plant species and ecological conditions. The data were collected from areas subjected to different fire severities. Overall 6 treatments were considered with respect to fire severity and the mi-crosites of inside and outside of oak sprout clumps including： unburned inside and outside of sprout clumps （Ni and No）, inside of sprout clumps that burned with high fire severity （H）, inside of sprout clumps that burned with moderate fire severity （M）, outside of sprout clumps that burned with low fire severity （OH and OM）. Different herbaceous com-position was observed in the unburned inside and outside of oak sprout clumps. The species diversity and richness were increased in treatments burned with low and moderate fire severity. However, in treatment burned with high fire severity （H）, herbaceous cover was reduced, even-ness was increased, and richness and diversity were not significantly changed. We concluded that besides the microsites conditions in forest, fire severity is an inseparable part of the ecological effect of fire on her-baceous composition.
基金funding of project is supported by Lorestan University,Iran。
文摘The response of diversity and biomass of herbaceous functional groups along an altitudinal gradient in mountainous forests of southern Zagros,Khuzestan Province,Iran was studied by sampling vegetation in 30 circular 1000-m^2 plots in herb layer of the forest floor within 646–2447 m asl(lowland:<1000 m asl,midland:1000–2000 m asl,highland:>2000 m asl).The most important herbaceous functional groups were classified based on two aspects of growth form:annuals–perennials,grasses–forbs.Then the relationship between the diversity,richness,evenness,biomass and elevation was analyzed.The results showed that the annual functional group in the low-and midland classes,and perennial functional group in the lowland class had the highest species diversity and evenness in annual and perennial functional groups,respectively(p<0.01).The perennials in the highland class had the maximum total,above-and belowground dry biomass(p<0.01).On the other hand,the forb functional group in the lowland class had the greatest species diversity,richness,and evenness(p<0.01)and in the highland class had the maximum total dry,above-and belowground dry biomass in the grass and forb functional groups(p<0.01).Increasing the diversity,richness,and species evenness resulted in a decrease in the plant dry biomass.
文摘The consequence of land-use change from forest to agriculture and other uses has become one of the world’s greatest concerns.The soil,one of the most important components of forests and containing all the required plant nutrients as soluble ions,is highly impacted by these changes.Because vast areas of the Zagros forests in western Iran have changed in use during the last few decades,the present study investigated the effects of landuse changes of forest area to agriculture,orchard,and agroforestry on soil chemical and physical properties.Soil was sampled at four land-use areas:less-disturbed forest areas(control)and agricultural,orchard,and agroforestry areas.Among each of the two forest-use areas(agroforestry and orchard),we selected five trees with similar-sized crowns and sampled under each tree crown at 0-15 and>15-30 cm depths.Five soil samples also were taken in agriculture area at each depth.The findings indicated that during land-use changes,soil sand particles decreased,and clay and silt particles of soil increased,resulting in a fine soil texture.Moreover,the amount of nitrogen(N),phosphorus(P),organic carbon(OC),and electrical conductivity(EC)of soil decreased at both depths due to the decrease in organic matter.Soil pH and magnesium(Mg)level rose during land-use change at both depths except at agricultural sites.Soil potassium(K)content decreased during agricultural use due to the elimination of tree cover.The level of K decreased only at the depth of 0-15 cm because of K dependency on parent materials.Generally,most soil nutrients were affected by plant removal in the conversion.Forest and agricultural soil are distinguishable by their properties,while land-uses such as agroforestry-orchard separated from the others.Soil nutrients were severely affected by the decrease and elimination of tree cover,plowing,and continuous harvesting,resulting in a decline in soil quality and fertility.
文摘The main aim of this study was to evaluate methods for fixed area and distance sampling in the Zagros open forest area in western Iran. Basic forest management and planning required appropriate quantitative and qualitative information. Two sampling methods were compared on the basis of the actual means of characteristics derived from the 100 % survey. In total, 37 sampling plots were systematically installed with a grid of 100 m × 100 m in the study area. Density, crown canopy, and basal area of the stands were measured. The 100 % survey showed that tree density above 12.5 cm diameter at breast height was 68.04 stem ha-1, basal area was 15.16 m2 ha-1 and crown canopy percentage was 35.71% ha-1. The values for the traits determined by the two sampling methods differed significantly （P = 0.05）. When the time required for the methods was compared, transect sampling required less than systematic-random sampling. Therefore, the transect sampling method was the more economical method for the Zagros open forests. The transect sampling method was statistically defensible and practical for quantitating characteristics of the Zagros open forests.
文摘The status of woody plants in dry-land systems is a fundamental determinant of key ecosystem processes. Monitoring of this status plays an important role in understanding the dynamics of woody plants in arid and semi-arid ecosystems. The present study determined the dynamism of the Zagros forests in Iran using Remote Sensing and Geographic Information System techniques and statistical science. The results show that the density of trees varied from 10 to 53 % according to the physio- graphic and climatic conditions of semi-arid regions. The best and lowest correlation between vegetation indices and forest density were obtained for the global environmental monitoring index （GEMI; R2 = 0.94） and soil adjust vegetation index （R2 = 0.81）, respectively. GEMI is used to monitor land use changes over a 10-year period. Results show that 2720 ha2 of forest have been destroyed by human interference and tillage on steep slopes during this period which also resulted in the loss of the fertile soil layer. GEMI determined the areas with a biomass of trees and could normally separate border regions with low bio- mass density of trees from regions without canopy cover. The results revealed that assessment of forest and vegetation cover in arid and semi-arid arduous forest regions using satellite digital numbers and ordinary sampling is subject to uncertainty. A stratified grouping procedure should be established to increase the accuracy of assessment.
文摘The Zagros forests are a treasure of valuable oak forests, but they have been severely degraded from long-term misuse. Geographic information systems （GIS） and multi-criteria decision analysis （MCDA） have been increasingly used to improve the management of vulnerable ecosystems to prevent further degradation and increase the sustainability of land use. This study presents a methodology to assess land suitability using remote sensing （RS） to obtain wall-to-wall data for the calculations, GIS to analyze the data, and MCDA to rank alternative land uses. The criteria and subcriteria affecting the suitability of land for different uses were identified and weighted using an analytic hierarchy process. Variables used as subcriteria were assessed using satellite data and other sources of information such as existing maps and field surveys. Numerical values for the subcriteria were classified, and each class was given a priority rating according to expert judgments. Based on the ratings and weights of the subcriteria, a priority map was created for each land use using the weighted linear combination method. The priority maps for different land uses were overlaid to obtain a preliminary land use map, which often indicated several simultaneous land uses for the same location. The preliminary map was further edited by removing unrealistic, mutually exclusive land-use combinations. The study tested and demonstrated the potential of integrating RS, G1S and MCDA techniques for solving complicated land allocation problems in forested regions using a scientifically sound and practical approach for efficient and sustainable allocation of forestland for different uses.
基金financially supported by the vice chancellor for research and technology of Urmia University and received no external funding.
文摘Forest edges have been well studied in temperate and tropical forests,but less so in open canopy forests.We investigated edge influence on plant species diversity and soil properties in sparse oak forest fragments.Data were collected along three transects from the edge to the interior of three small(under 10 ha)and three large(over 10 ha)oak forest fragments in Kermanshah Province,Iran.We measured herbaceous plants(<0.5 m in height)and soil attributes at 0(forest edge),25,50,100 and 150 m.We quantified species diversity using the Shannon index,used rarefaction to compare species richness between two different sizes of fragments and applied non-metric multidimensional scaling ordination to investigate the variation in species composition.We estimated the distance of edge influence using randomization tests.Generalized linear mixed models with post-hoc Tukey’s HSD tests were used to assess the effects of distance from edge and fragment size on diversity and soil properties.We found greater species richness,diversity and evenness at the edge of both small and large fragments and lower nitrogen and organic carbon at the edge compared to the interior of large fragments,with most changes within 50 m of the edge.Species composition,organic carbon and total nitrogen were significantly different between small and large fragments.Our findings of significant edge influence on herbaceous plants and soil properties in these sparse forests provide a significant contribution to the literature on edges,especially in relation to herbaceous plants.
