The Chinese Grouse (Tetrastes sewerzowi) is a rare, endemic bird in China, inhabiting conifer-dominated mountain forests. Both the natural fragmentation and heavy cutting of mature forests have resulted in patchy grou...The Chinese Grouse (Tetrastes sewerzowi) is a rare, endemic bird in China, inhabiting conifer-dominated mountain forests. Both the natural fragmentation and heavy cutting of mature forests have resulted in patchy grouse habitats. We used SPOT (XS-sensor) satellite imagery to discriminate between open land and conifer or broadleaf forests. The area analyzed is about 120000 ha in size and includes the Lianhuashan Nature Reserve and the Yeliguan Forestry Park. We identiifed 4111 ha of mature coniferous forests in 229 patches (maximum 332 ha, mean 18 ha) as the habitat used by Chinese Grouse throughout the year. We examined 31 forest islands of different sizes and degrees of isolation for the presence of Chinese Grouse. We used generalized linear models (GLM) with binomial error structure and logit link function to estimate the probability of Chinese Grouse occupancy in a forest fragment. Habitat patch size (hs) and distance to the next occupied fragment (doc) were used as predictor variables, important for occupancy. Small habitat islands were disproportionately less likely to be occupied than large, nearby habitats. There was a clear speciifc habitat size of about 40 ha, above which habitat fragments were occupied more often. Suitable habitat fragments isolated by more than 2 km appeared to be inaccessible to Chinese Grouse. The results have been used in reforestation projects to establish linking corridors in the study area.展开更多
The problem of habitat fragmentation is recently an important issue in ecological research as well as in the practical approach of nature conservation. According to the most popular approaches, habitats are considered...The problem of habitat fragmentation is recently an important issue in ecological research as well as in the practical approach of nature conservation. According to the most popular approaches, habitats are considered as the homogenous parts of the landscape. Also the metapopulation concept problem of the inert habitat heterogenity is considered quite seldom. These approaches have some weak points resulting from the assumption that the border between habitat patches and the metapopulation matrix is fairly sharp. This paper presents a resource-based concept of habitats, based on mathematical theory of point processes, which can be easily applied to analysing the problem of uneven distribution of resources. The basic assumption is that the random distribution of resources may be mathematically described as the realisation of a certain point process. According to our method, it is possible to calculate the expected quantities of available resources as well as the minimum area of habitat that includes the expected abundance of the resource. This approach may be very useful to understand some crucial phenomena in landscape ecology, such as the patch size effect and its connection to habitat loss and fragmentation.展开更多
Forest disturbances have been altering the ecological properties of ecosystems;meanwhile,disturbance events of varying sizes create different structures and functions for a forest landscape.Therefore,size and frequenc...Forest disturbances have been altering the ecological properties of ecosystems;meanwhile,disturbance events of varying sizes create different structures and functions for a forest landscape.Therefore,size and frequency are important attributes of disturbances,and their relationship should be studied.We present a hierarchical method through the modeling of the overall trend of the size–frequency distribution and the characterization of the non-constant variances of disturbance sizes at each frequency level.This method was demonstrated to accurately model the sizes as well as the corresponding frequencies;thus,the total disturbed area and number of disturbance patches were both accurately estimated.By applying the method to 13 provinces in China,consistent patterns were revealed by the modeling results and remote-sensing-based product,showing that between 2000 and 2005,forests in most provinces were dominated by moderate disturbances(10 ha<size<100 ha).Southeastern provinces contain the largest proportion of small disturbances(size<10 ha),whereas most of the very large disturbances(size>1000 ha)occurred in the northeastern and northwestern provinces.This study concludes that the proposed method can improve the representation of the size–frequency distribution of forest disturbances.展开更多
Focal plants are considerably affected by their neighbouring plants,especially when growing in heterogeneous soils.A previous study on grasses demonstrated that soil heterogeneity and species composition affected plan...Focal plants are considerably affected by their neighbouring plants,especially when growing in heterogeneous soils.A previous study on grasses demonstrated that soil heterogeneity and species composition affected plant biomass and above-and belowground allocation patterns.We now tested whether these findings were similar for forbs.Three forb species(i.e.Spartina anglica,Limonium bicolor and Suaeda glauca)were grown in pots with three levels of soil heterogeneity,created by alternatively filling resource-rich and resource-poor substrates using small,medium or large patch sizes.Species compositions were created by growing these forbs either in monocultures or in mixtures.Results showed that patch size×species composition significantly impacted shoot biomass,root biomass and total biomass of forbs at different scales.Specifically,at the pot scale,shoot biomass,root biomass and total biomass increased with increasing patch size.At the substrate scale,shoot biomass and total biomass were higher at the large patch size than at the medium patch size,both in resource-rich and resource-poor substrates.Finally,at the community scale,monocultures had more shoot biomass,root biomass and total biomass than those in the two-or three-species mixtures.These results differ from earlier findings on the responses of grasses,where shoot biomass and total biomass decreased with patch size,and more shoot biomass and total biomass were found in resource-rich than resource-poor substrates.To further elucidate the effects of soil heterogeneity on the interactions between neighbour plants,we advise to conduct longer-term experiments featuring a variety of functional groups.展开更多
Aims Soil heterogeneity is common in natural habitats.It may trigger for-aging responses(placing more ramets and/or roots in nutrient-rich patches than in nutrient-poor patches)and further affect the growth of plants....Aims Soil heterogeneity is common in natural habitats.It may trigger for-aging responses(placing more ramets and/or roots in nutrient-rich patches than in nutrient-poor patches)and further affect the growth of plants.However,the impact of soil heterogeneity on competitive interactions has been little tested.Methods We conducted a greenhouse experiment to investigate the effects of soil heterogeneity on intraspecific competition with a stolonif-erous herb Hydrocotyle vulgaris.We grew one(without com-petition)or nine ramets(with competition)of H.vulgaris under a homogeneous environment and two heterogeneous environ-ments differing in patch size(large or small patches).In the het-erogeneous treatment,the soil consisted of the same number of nutrient-rich and nutrient-poor patches arranged in a chessboard manner,and in the homogeneous treatment,the soil was an even mixture of the same amount of the nutrient-rich and the nutrient-poor soil.Important Findings Irrespective of intraspecific competition,H.vulgaris showed for-aging responses to soil heterogeneity in the large patch treatment,e.g.it produced significantly more biomass,ramets,aboveground mass and root mass in the nutrient-rich patches than in the nutrient-poor patches.In the small patch treatment,foraging responses were observed when intraspecific competition was present,but responses were not observed when there was no competition.However,we find a significant effect of soil heterogeneity on neither overall growth nor competitive intensity of H.vulgaris.Our results suggest that foraging responses to soil heterogeneity may not necessarily be adaptive and intraspecific competition may not be influenced by soil heterogeneity.展开更多
In this study, we compared ground-dwelling beetle assemblages （Coleoptera） from a range of different oak fragments and surrounding conifer plantations to evaluate effects of forest size and surrounding matrix habita...In this study, we compared ground-dwelling beetle assemblages （Coleoptera） from a range of different oak fragments and surrounding conifer plantations to evaluate effects of forest size and surrounding matrix habitat in a temperate forest of north China. During 2000, beetles were sampled via pitfall traps within two large oak fragments （ca. 2.0-4.0 ha）, two small oak fragments （ca. 0.2-0.4 ha） and two surrounding matrices dom- inated by pine plantations （〉4 ha） in two sites of different aspects. Overall, no significantly negative effects from forest patch size and the surrounding matrix habitat were detected in total species number and abundance of ground-dwelling beetles. However, compared with small oak patches or pine plantations, more species were associated with an affinity for at least one large oak patch of the two aspects. Multivariate regression trees showed that the habitat type better determined the beetle assemblage structure than patch size and aspect, indicating a strong impact of the surrounding matrix. Linear mixed models indicated that species richness and abundance of all ground-dwelling beetles or beetle families showed different responses to the selected environmental variables. Our results suggest that more disturbed sites are significantly poorer in oak forest specialists, which are usually more abundant in large oak fragments and decrease in abundance or disappear in small fragments and surrounding matrix habitats. Thus, it is necessary to preserve a minimum size of forest patch to create conditions characteristic for forest interior, rather than the more difficult task of increasing habitat connectivity.展开更多
Aims Soil heterogeneity is ubiquitous in many ecosystems.We hypothesized that plant communities with higher species richness might be better adapted to soil heterogeneity and produce more biomass than those with lower...Aims Soil heterogeneity is ubiquitous in many ecosystems.We hypothesized that plant communities with higher species richness might be better adapted to soil heterogeneity and produce more biomass than those with lower richness.This is because there is niche differentiation among species and different species can complement each other and occupy a broader range of niches when plant species richness is high.However,no study has tested how soil particle heterogeneity affects the yield of plant communities,and whether such effects depend on the spatial scale of the heterogeneity and the species richness within the communities.Methods In a greenhouse experiment,we sowed seeds of four-species or eight-species mixtures in three heterogeneous treatments consisting of 32,8 or 2 patches of both small(1.5 mm)and large quartz(3.0 mm)particles arranged in a chessboard manner and one homogeneous treatment with an even mixture of small and large quartz particles.Important Findings Biomass production was significantly greater in the communities with high species richness than those with low species richness.However,soil particle heterogeneity or its interactions with patch scale or species richness did not significantly affect biomass production of the experimental communities.This work indicates that plant species richness may have a bigger impact on plant productivity than soil particle heterogeneity.Further studies should consider multiple sets of plant species during longer time periods to unravel the potential mechanisms of soil heterogeneity and its interactions with the impacts of species richness on community yield and species coexistence.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.31270468,30620130110)
文摘The Chinese Grouse (Tetrastes sewerzowi) is a rare, endemic bird in China, inhabiting conifer-dominated mountain forests. Both the natural fragmentation and heavy cutting of mature forests have resulted in patchy grouse habitats. We used SPOT (XS-sensor) satellite imagery to discriminate between open land and conifer or broadleaf forests. The area analyzed is about 120000 ha in size and includes the Lianhuashan Nature Reserve and the Yeliguan Forestry Park. We identiifed 4111 ha of mature coniferous forests in 229 patches (maximum 332 ha, mean 18 ha) as the habitat used by Chinese Grouse throughout the year. We examined 31 forest islands of different sizes and degrees of isolation for the presence of Chinese Grouse. We used generalized linear models (GLM) with binomial error structure and logit link function to estimate the probability of Chinese Grouse occupancy in a forest fragment. Habitat patch size (hs) and distance to the next occupied fragment (doc) were used as predictor variables, important for occupancy. Small habitat islands were disproportionately less likely to be occupied than large, nearby habitats. There was a clear speciifc habitat size of about 40 ha, above which habitat fragments were occupied more often. Suitable habitat fragments isolated by more than 2 km appeared to be inaccessible to Chinese Grouse. The results have been used in reforestation projects to establish linking corridors in the study area.
基金funded by Institute of Nature Conservation PASpartly by a Polish State Committee for Scientific Research/National Science Centre grant No.N N304 325836.
文摘The problem of habitat fragmentation is recently an important issue in ecological research as well as in the practical approach of nature conservation. According to the most popular approaches, habitats are considered as the homogenous parts of the landscape. Also the metapopulation concept problem of the inert habitat heterogenity is considered quite seldom. These approaches have some weak points resulting from the assumption that the border between habitat patches and the metapopulation matrix is fairly sharp. This paper presents a resource-based concept of habitats, based on mathematical theory of point processes, which can be easily applied to analysing the problem of uneven distribution of resources. The basic assumption is that the random distribution of resources may be mathematically described as the realisation of a certain point process. According to our method, it is possible to calculate the expected quantities of available resources as well as the minimum area of habitat that includes the expected abundance of the resource. This approach may be very useful to understand some crucial phenomena in landscape ecology, such as the patch size effect and its connection to habitat loss and fragmentation.
基金supported by the Natural Science Foundation of China[grant number 41901300]the Fundamental Research Funds for the Central Universities[grant number CCNU19TD002]the Scientific Research Project of Department of Natural Resources of Hubei Province[grant number ZRZY2020KJ01].
文摘Forest disturbances have been altering the ecological properties of ecosystems;meanwhile,disturbance events of varying sizes create different structures and functions for a forest landscape.Therefore,size and frequency are important attributes of disturbances,and their relationship should be studied.We present a hierarchical method through the modeling of the overall trend of the size–frequency distribution and the characterization of the non-constant variances of disturbance sizes at each frequency level.This method was demonstrated to accurately model the sizes as well as the corresponding frequencies;thus,the total disturbed area and number of disturbance patches were both accurately estimated.By applying the method to 13 provinces in China,consistent patterns were revealed by the modeling results and remote-sensing-based product,showing that between 2000 and 2005,forests in most provinces were dominated by moderate disturbances(10 ha<size<100 ha).Southeastern provinces contain the largest proportion of small disturbances(size<10 ha),whereas most of the very large disturbances(size>1000 ha)occurred in the northeastern and northwestern provinces.This study concludes that the proposed method can improve the representation of the size–frequency distribution of forest disturbances.
基金supported by the Open Fund of Key Laboratory of Biodiversity and Environment on the Qinghai-Tibet Plateau,Ministry of Education(KLBE2024002)a start-up fund from Lanzhou University(508000-561119213).
文摘Focal plants are considerably affected by their neighbouring plants,especially when growing in heterogeneous soils.A previous study on grasses demonstrated that soil heterogeneity and species composition affected plant biomass and above-and belowground allocation patterns.We now tested whether these findings were similar for forbs.Three forb species(i.e.Spartina anglica,Limonium bicolor and Suaeda glauca)were grown in pots with three levels of soil heterogeneity,created by alternatively filling resource-rich and resource-poor substrates using small,medium or large patch sizes.Species compositions were created by growing these forbs either in monocultures or in mixtures.Results showed that patch size×species composition significantly impacted shoot biomass,root biomass and total biomass of forbs at different scales.Specifically,at the pot scale,shoot biomass,root biomass and total biomass increased with increasing patch size.At the substrate scale,shoot biomass and total biomass were higher at the large patch size than at the medium patch size,both in resource-rich and resource-poor substrates.Finally,at the community scale,monocultures had more shoot biomass,root biomass and total biomass than those in the two-or three-species mixtures.These results differ from earlier findings on the responses of grasses,where shoot biomass and total biomass decreased with patch size,and more shoot biomass and total biomass were found in resource-rich than resource-poor substrates.To further elucidate the effects of soil heterogeneity on the interactions between neighbour plants,we advise to conduct longer-term experiments featuring a variety of functional groups.
基金Specific Programs in Graduate Science and Technology Innovation of Beijing Forestry University(BLYJ201204)the Fundamental Research Funds for the Central Universities(TD-JC-2013-1)+1 种基金the Program for New Century Excellent Talents in University(NECT-10-0234)the National Natural Science Foundation of China(31200314).
文摘Aims Soil heterogeneity is common in natural habitats.It may trigger for-aging responses(placing more ramets and/or roots in nutrient-rich patches than in nutrient-poor patches)and further affect the growth of plants.However,the impact of soil heterogeneity on competitive interactions has been little tested.Methods We conducted a greenhouse experiment to investigate the effects of soil heterogeneity on intraspecific competition with a stolonif-erous herb Hydrocotyle vulgaris.We grew one(without com-petition)or nine ramets(with competition)of H.vulgaris under a homogeneous environment and two heterogeneous environ-ments differing in patch size(large or small patches).In the het-erogeneous treatment,the soil consisted of the same number of nutrient-rich and nutrient-poor patches arranged in a chessboard manner,and in the homogeneous treatment,the soil was an even mixture of the same amount of the nutrient-rich and the nutrient-poor soil.Important Findings Irrespective of intraspecific competition,H.vulgaris showed for-aging responses to soil heterogeneity in the large patch treatment,e.g.it produced significantly more biomass,ramets,aboveground mass and root mass in the nutrient-rich patches than in the nutrient-poor patches.In the small patch treatment,foraging responses were observed when intraspecific competition was present,but responses were not observed when there was no competition.However,we find a significant effect of soil heterogeneity on neither overall growth nor competitive intensity of H.vulgaris.Our results suggest that foraging responses to soil heterogeneity may not necessarily be adaptive and intraspecific competition may not be influenced by soil heterogeneity.
文摘In this study, we compared ground-dwelling beetle assemblages （Coleoptera） from a range of different oak fragments and surrounding conifer plantations to evaluate effects of forest size and surrounding matrix habitat in a temperate forest of north China. During 2000, beetles were sampled via pitfall traps within two large oak fragments （ca. 2.0-4.0 ha）, two small oak fragments （ca. 0.2-0.4 ha） and two surrounding matrices dom- inated by pine plantations （〉4 ha） in two sites of different aspects. Overall, no significantly negative effects from forest patch size and the surrounding matrix habitat were detected in total species number and abundance of ground-dwelling beetles. However, compared with small oak patches or pine plantations, more species were associated with an affinity for at least one large oak patch of the two aspects. Multivariate regression trees showed that the habitat type better determined the beetle assemblage structure than patch size and aspect, indicating a strong impact of the surrounding matrix. Linear mixed models indicated that species richness and abundance of all ground-dwelling beetles or beetle families showed different responses to the selected environmental variables. Our results suggest that more disturbed sites are significantly poorer in oak forest specialists, which are usually more abundant in large oak fragments and decrease in abundance or disappear in small fragments and surrounding matrix habitats. Thus, it is necessary to preserve a minimum size of forest patch to create conditions characteristic for forest interior, rather than the more difficult task of increasing habitat connectivity.
基金Fundamental Research Funds for the Central Universities(TD-JC-2013-1)NSFC(31570413).
文摘Aims Soil heterogeneity is ubiquitous in many ecosystems.We hypothesized that plant communities with higher species richness might be better adapted to soil heterogeneity and produce more biomass than those with lower richness.This is because there is niche differentiation among species and different species can complement each other and occupy a broader range of niches when plant species richness is high.However,no study has tested how soil particle heterogeneity affects the yield of plant communities,and whether such effects depend on the spatial scale of the heterogeneity and the species richness within the communities.Methods In a greenhouse experiment,we sowed seeds of four-species or eight-species mixtures in three heterogeneous treatments consisting of 32,8 or 2 patches of both small(1.5 mm)and large quartz(3.0 mm)particles arranged in a chessboard manner and one homogeneous treatment with an even mixture of small and large quartz particles.Important Findings Biomass production was significantly greater in the communities with high species richness than those with low species richness.However,soil particle heterogeneity or its interactions with patch scale or species richness did not significantly affect biomass production of the experimental communities.This work indicates that plant species richness may have a bigger impact on plant productivity than soil particle heterogeneity.Further studies should consider multiple sets of plant species during longer time periods to unravel the potential mechanisms of soil heterogeneity and its interactions with the impacts of species richness on community yield and species coexistence.
