[Critical influencing factors on vegetation productivity in sandy land of the Northwestern Liaoning Province,China]. / è¾½è¥¿åŒ—æ²™åŒ–åœŸåœ°æ¤è¢«ç”Ÿäº§åŠ›å ³é”®å½±å“å› ç´ .

To reveal the key factors influencing vegetation productivity in sandy lands, we conducted a comprehensive analysis of vegetation productivity on regional scale, pixel scale, and plot scale of the sandy lands in northwes-tern Liaoning Province, based on soil physicochemical data, topographical data, climate data, and the intrinsic characteristics of vegetation. On the regional scale, we established a random forest model to explore the impact of topographical factors, climate factors, and vegetation characteristics on vegetation productivity. On the pixel scale, we performed a correlation analysis between vegetation cover and climate factors. On the plot scale, we combined the physicochemical properties of 234 soil samples with topographical factors and vegetation characteristics, and utilized the random forest model to calculate the importance values of each factor. The results showed that soil nutrients could explain 24.8% of the spatial variation in net primary productivity when other factors were excluded. When introducing topographical factors into the model, the model could explain 40% variation of net primary productivity. When further incorporating fractional vegetation coverage and leaf area index into the model, the model could explain 72.8% variation of net primary productivity. Our findings suggested that fractional vegetation coverage and leaf area index were the most influential factors affecting vegetation productivity in this area. Topographical factors ranked second, followed by climate factors, which had a relatively small impact.

[Latitudinal variations of seed functional traits of Phragmites australis in Chinese coastal marsh]. / 中国滨海沼泽湿地芦苇种子功能性状的纬度梯度变异.

Functional traits of seeds reflect plant reproductive strategies adapting to environmental changes, which is an evolutionary behavior in natural selection and genetics. Study on seed functional traits is of great significance to deeply understand the long-term adaptive evolution of plants and seeds. We measured seed functional traits of a main indigenous species Phragmites australis, including seed size, seed weight, seed set, and seed production, in nine coastal marshes of the six provinces/cities along the coastal zone of China (21°29'-40°57' N), and analyzed latitudinal variations of functional traits. The results showed that seed functional traits of P. australis in Chinese coastal marshes varied significantly with latitude and that there were significant correlations among different traits. Seed size (including seed length, seed width, seed shape index, aspect ratio, and seed surface area), and 100-seed weight showed significant quadratic function relation with latitude, which firstly decreased and then increased with the increases of latitude, while seed setting rate firstly increased and then reduced. There was a trade-off between the number and size of P. australis seeds. Seed production per unit area significantly increased with latitude. Results of stepwise regression analysis showed that climatic factors were the main driver resulting in the difference of seed functional traits of P. australis between latitudes, followed by pH and salinity of soil porewater.

[Effects of forest ownership regime on landscape pattern and animal habitat: a review].

In some European and North American countries where forestry is highly developed, both public and private forest ownership regimes have being existed for a long time. Currently, the researches about both the dynamics of forest landscape and habitat pattern and the relationship between habitat pattern and biological conservation in multi-ownership forest landscape are increasingly becoming important. This paper reviewed the effects of multi-ownership regime on forest landscape pattern and animal habitat and emphasized on the ecological consequences of forest parcelization and land divestiture, including the provision of diverse habitats and fragmentation of the existing large-area habitat. This paper also summarized two ways (changing the ownership pattern and integrating the multi-ownership management by cross boundary coordination) for handling the conflicts between small-scaled multi-ownership management and biological conservation at large scale in forestry-developed countries and analyzed the reasons that those countries prefer to adopt the latter one. Furthermore, the methodological limitations in simulating ownership pattern were pointed out. Finally, the present status, challenges and opportunities in the above-mentioned research issues in China were discussed, and the suggestions for further researches were provided.

[Effects of spatial heterogeneity on spatial extrapolation of sampling plot data].

By using model combination method, this paper simulated the changes of response variable (tree species distribution area at landscape level under climate change) under three scenarios of environmental spatial heterogeneous level, analyzed the differentiation of simulated results under different scenarios, and discussed the effects of environmental spatial heterogeneity on the larger spatial extrapolation of the tree species responses to climate change observed in sampling plots. For most tree species, spatial heterogeneity had little effects on the extrapolation from plot scale to class scale; for the tree species insensitive to climate warming and the azonal species, spatial heterogeneity also had little effects on the extrapolation from plot-scale to zonal scale. By contrast, for the tree species sensitive to climate warming, spatial heterogeneity had effects on the extrapolation from plot scale to zonal scale, and the effects could be varied under different scenarios.

[Simulation of timber-harvesting area in Xiao Xing' anling Mountains under climate change].

By using the spatially explicit forest landscape model (LANDIS 6.0 PRO), the percentages of timber-harvesting area in Xiao Xing' anling Mountains under current harvesting scenario and under 11 harvesting scenarios with alternating harvesting intensities (alternating time was 10, 20 and 30 years, respectively) in 2000-2400 under climate change were simulated. Alternating harvesting intensity could increase the harvesting area. Comparing with current harvesting scenario, the simulated scenarios could increase the harvesting area by 3%-5% at short term (10-30 years), 2.5%-7% at medium term (40-60 years), and 3.5%-8% at long term (70-100 years). On the whole, the current total harvesting area was still high. Alternating harvesting-intensity could increase the harvesting area within a definite term, but the effect would be unsustainable. To have a sustainable development of forestry in the study area, it is necessary to reduce the harvesting intensity and change the forest management policy.

[Effects of eco-protection policy on land use/cover in upper reaches of Minjiang River].

By using CLUE-S model, a scenario analysis was made on the land use/cover change in the upper reaches of Minjiang River from 2000 to 2020, based on the historic development trend and the regulations of policies "natural forest protection" and "grain for green". In 2000-2020, according to the historic development trend, the forestland area (landscape matrix) in the study region would have a continual decrease while the shrub land and grassland areas would be increased, and the landscape pattern would be more fragmental. The implementation of the policies "natural forest protection" and "grain for green" would effectively increase forestland area, being able to reverse the trend of landscape fragmentation and more optimize the landscape pattern.

[Long-term effects of Dendrolimus superans Bulter disturbance on forest landscape in Huzhong Forest Bureau of Great xing' an Mountains: a simulation study].

A spatially explicit landscape model LANDIS was applied to simulate the long-term effects of Dendrolimus superans Bulter disturbance on the forest landscape in Huzhong Forest Bureau of Great Xing' an Mountains. The statistical software pakage APACK was used to calculate the distribution area of D. superans and representative tree species, the aggregation index reflecting the spatial pattern, and the average area of forest patchs. The dynamics of forest landscape in the study region was simulated under two scenarios, i.e., with and without D. superans disturbance for 300 years (from 1990 to 2290). In the region, the distribution area of D. superans showed a trend of increased first and decreased then. Under D. superans disturbance scenario, the distribution area and the average patch size of Larix gmelinii in 0-150 years and the aggregation index of L. gmelinii in 0-190 years, the distribution area and the average patch size of Betula platyphylla and its aggregation index in 80-190 years, as well as the distribution area, average patch size, and aggregation index of Pinus sylvestris var. mongolica were lower or slightly lower than those under no disturbance scenario. D. superans disturbance led to the fragmentation of forest landscape to some extent.

[Soil respiration of degraded Korean pine forest ecosystem in Changbai Mountains].

Taking the broad-leaved Korean pine forest area in Changbai Mountains, a typical eastern forest belt of Northeast China for global change as test object, and by using the approaches of trenching-plot and infrared gas exchange analyzer, this paper analyzed the soil respiration in a selected series of degraded Korean pine forest ecosystem, i.e., broad-leaved Korean pine forest (CK), poplar-birch forest (Y), hardwood forest (S), Mongolian oak forest (M), and bare land (L). In the growth season of the forests, soil respiration showed a clear single peak curve, with the maximum in July or August. The soil respiration decreased in the sequence of Y>M>CK>S>L. The amount of CO2 release in Y and M was about 0.4 and 0.3 times higher than that in CK; and that in S and L accounted for 88% and 78% of CK, respectively.

[Effect zone of forest road on plant species diversity in Great Hing 'an Mountains].

Forest road has far-reaching effects on plant species diversity across varying scales, and the estimation of its effect distance and effect zone is a key issue to integrate the road effect and ecological processes in forest area. In this paper, ten transects, 2 m wide and extending 50 m from varying grade roads including main road, main line for wood transportation, and secondary line for wood transportation in Huzhong forest area of Great Hing' an Mountains were set. The plant composition was investigated in twenty-five 2 m x 2 m plots of each transect. The road-effect distance on plant species diversity identified by moving window analysis in terms of the important value of each plot. The results showed that in study area, the effect distance reached up to 20-34 m, regardless of the roads grade. The plant species diversity of shrub stratum and herb stratum within the effect zone was greater than that in adjacent habitat, with the Shannon-Weiner index increased by 21% and 60%, respectively. The response of shrub stratum to the road effect was more stable than herb stratum, but no significant change was observed in tree stratum. Chamaenerion angustifolium was the indicative species of road-effect zone communities. Based on the estimation of road-effect distance, the road area in Huzhong Forestry Bureau and Great Hing' an Mountains occupied about 0.10%, and its effect zone on vegetation occupied 1.79% and 1.53%, respectively.

[Modeling of forest landscape change in Xiaoxinganling mountains under different planting proportions of coniferous and broadleaved species].

With spatially explicit landscape model (LANDIS), the dynamic change of forest landscape in Youhao Forest Bureau in Xiaoxinganling Mountains from 2001-2201 under 5 planting proportions of coniferous and broadleaved species, i.e., 100% broadleaved species, 70% broadleaved and 30% coniferous species, 50% broadleaved and 50% coniferous species, 30% broadleaved and 70% coniferous species, and 100% coniferous species, was studied, taking the forest under natural regeneration after harvesting as the control. The results showed that afforestation effectively promoted the recovery of forest resources, but single planting of coniferous species would lead to the area percent of broadleaved species lower than the control. When broadleaved species were planted only, the area percent of coniferous species was lower than the control. The area percent and aggregation index of Pinus koraiensis and Larix gmelini increased with increasing planting proportion of coniferous species, and those of Quercus mongolica increased with increasing planting proportion of broad-leaved species. Afforestation decreased the area percent of Betula phatyphylla, but had no significant effects on its aggregation index. Different afforestation strategies not only altered the species area percent, but also affected the species spatial pattern.

[Effects of different forest management alternatives on Sciurus vulgaris habitat].

A spatially explicit landscape model LANDIS was applied to simulate the forest landscape changes under four management alternatives (no cutting, clear cutting, selective cutting I and II) in Youhao Forestry Bureau located in Small Xing' an Mountain from 2000 to 2200. The outcomes from LANDIS were combined with a landscape-level habitat suitability index (HSI) model in a GIS environment to assess Sciurus vulgaris habitat quality. The results showed that the increase of suitable habitat area and the decrease of marginally suitable area were the fastest under no cutting scenario, and the slowest under clear cutting scenario. Suitable habitat area increased faster while marginally suitable area decreased more slowly under selective cutting I scenario than under selective cutting II. Overall, the optimal management alternative of S. vulgaris habitat was in the sequence of no cutting, selective cutting I, selective cutting II, and clear cutting.

[Dynamics and influence width of dry valley landscape boundary in upper reaches of Minjiang River].

Based on RS and GIS techniques, the distribution extent of the dry valley in upper reaches of Minjiang River was determined, with the dynamics and influence width of its landscape boundary analyzed. The results indicated that the dry valley had a gradually expanded distribution, and the total length of its boundary was increased. The boundary complexity increased from 1974 to 1995 but decreased from 1995 to 2000, and the upper boundary of the dry valley ascended rapidly along mountain slope. The uppermost elevation of the dry valley boundary was 3128 m in 1974, 3167 m in 1995, and 3181 m in 2000. In the last 26 years, the upper boundary of the dry valley ascended 53 m in total, being about 2 m per year. The influence width of the dry valley boundary was 800 m, which could be regarded as a buffer zone to disturbances. The area between 800-1200 m from the dry valley boundary to exterior was a transition zone intensely influenced by the dry valley and its surrounding landscape, which should be addressed in the restoration of the dry valley.

[Landscape change and its spatial driving force of farmlands in Wenchuan County of Min-jiang River upper reach].

Based on remote sensing images and geographic information system, and by using landscape metrics and Kappa coefficient, this paper studied the farmland landscape change in Wenchuan County of Minjiang River upper reach. A logistic regression model was used to analyze the driving forces of this change, with elevation, gradient, aspect, and the distances to road, river and settlement as the affecting factors. The results showed that from 1974 to 2000, the farmland area in Wenchuan County kept increasing, with the greatest increment in 1974-1986. In 1986-2000, farmland area had no evident increase, but converted with other landscape types frequently and had an evident spatial position change, especially in the period from 1994 to 2000. Such a farmland change was mainly driven by policy, and the spatial driving forces differed in different periods.

[Spatiotemporal pattern and its driving forces of urban growth in Shenyang City].

By using time series Landsat TM satellite images and adopting GIS spatial analysis and landscape pattern analysis methods, this paper studied the spatiotemporal diversity of urban growth and the evolution of urban landscape pattern in Shenyang, and examined their driving forces. The results showed that in 1988-2004, the urban area in Shenyang increased persistently, and the growth intensity enhanced consistently, with the peaks occured in 2000-2004. The spatial differentiation of urban growth in the City was also distinct, with the southwest direction as the leading orientation, and the urban edges and different level economic development zones as the main growth areas. The urban landscape pattern became more and more complex, and the compactness index of urban development decreased. The evolution of urban landscape pattern was related to the characteristics of urban growth, which also showed spatiotemporal diversity. The urban growth and urban landscape pattern evolution in Shenyang were mainly attributed to the development of industrialization and the construction of different level economic development zones, the proper policies of local governments and the urban planning, as well as the development of traffic infrastructure.

Detecting forest landscape boundary between mountain birch and evergreen coniferous forest in the northern slope of Changbai Mountain.

Boundaries between different forest types in Changbai Mountain Eastern China are results from complex interactions between forest ecosystems, topography, and geomorphology. Detecting and quantifying the transitional zones are highly important since high environmental heterogeneity and biodiversity are often found within these zones. In this study, we used GIS and multivariate statistics techniques (PCA and MSWA) to analyze data from Landsat TM satellite imageries and quantitatively determined the positions and widths of the landscape boundary between mountain birch and evergreen coniferous forests in the northern slope of Changbai Mountain. The results showed that the widths of the landscape boundary ranges from 30-50 m while using the MSWA or/and PC method. Such detected widths are consistent with field transect data that suggests a 50 m transitional zone width. The results further suggest that TM data can be used in combination with GIS and statistical techniques in determining forest landscape boundaries; MSWA is more reliable than PCA, while PCA can also be used to determine the landscape boundary when transects are properly located.