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Forest patch dynamics initiated by disturbance: distribution pattern of Larix chinensis (Bessen) patches along the altitudinal gradient in relation to light and temperature conditions (Qinling Mts. China)

100%

Duan R.-Y. , Huang M.-Y. , Wang X.-A.

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tom 61

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nr 2

EN

According to the theory of forest growth cycle, forest communities are dynamic mosaic systems composed of patches in different development stages. On basis of measurement of the four patch types [gap phase (G), building phase (B), mature phase (M) and degenerate phase (D)], the distribution pattern of different patch types and heterogeneity of the light and temperature along an altitudinal gradient were analyzed. The study forests were located in Larix chinensis forests in the Taibai Natural Reserve, and the whole forest was divided into three transects, i.e. low altitude (2900–3000 m a.s.l.), middle altitude (3100–3200 m a.s.l.) and high altitude (3300–3400 m a.s.l.). The implications of environmental heterogeneity on species coexistence and maintenance of species diversity were discussed in this paper. Our results were as follows: (1) In different elevation gradient, the proportions of the four patch types were different. Compared with low elevation and high elevation, in middle elevation, the proportions of gap phase and building phase were obviously lower; while the proportions of mature phase and degenerate phase were noticeably higher. In different elevation gradient, the distribution pattern of the four patch types was changed to some extent. (2) The daily change patterns of light and temperature in different patch types in forest cycle were different. The light intensity was much greater in gap phase than in the other three phases. The light intensity and its amplitude of changes in different patch types followed the order of G>D>B≥M. Air temperature in different patch types followed the order of G>B>D≥M. The amplitude of diurnal temperature changes in air and soil surface followed the order of G>D>B>M. (3) With elevation increasing, light intensity, the biggest air temperature, biggest soil temperature and temperature difference in four patch phase increased significantly, and average air temperature and average soil temperature significantly decreased. The spatio-temporal heterogeneity of ecological factors in different patch types in forest cycle provided a basis to maintain the coexistence of different species with different characteristics within forest community.

2

Forest patch dynamics initiated by disturbance: distribution pattern of Larix chinensis (Bessen) patches along the altitudinal gradient in relation to light and temperature conditions (Qinling Mts. China)

100%

Duan R.-Y. , Huang M.-Y. , Wang X.-A.

Polish Journal of Ecology

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2013

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tom Vol. 61, nr 2

271--281

EN

According to the theory of forest growth cycle, forest communities are dynamic mosaic systems composed of patches in different development stages. On basis of measurement of the four patch types [gap phase (G), building phase (B), mature phase (M) and degenerate phase (D)], the distribution pattern of different patch types and heterogeneity of the light and temperature along an altitudinal gradient were analyzed. The study forests were located in Larix chinensis forests in the Taibai Natural Reserve, and the whole forest was divided into three transects, i.e. low altitude (2900–3000 m a.s.l.), middle altitude (3100–3200 m a.s.l.) and high altitude (3300–3400 m a.s.l.). The implications of environmental heterogeneity on species coexistence and maintenance of species diversity were discussed in this paper. Our results were as follows: (1) In different elevation gradient, the proportions of the four patch types were different. Compared with low elevation and high elevation, in middle elevation, the proportions of gap phase and building phase were obviously lower; while the proportions of mature phase and degenerate phase were noticeably higher. In different elevation gradient, the distribution pattern of the four patch types was changed to some extent. (2) The daily change patterns of light and temperature in different patch types in forest cycle were different. The light intensity was much greater in gap phase than in the other three phases. The light intensity and its amplitude of changes in different patch types followed the order of G>D>B≥M. Air temperature in different patch types followed the order of G>B>D≥M. The amplitude of diurnal temperature changes in air and soil surface followed the order of G>D>B>M. (3) With elevation increasing, light intensity, the biggest air temperature, biggest soil temperature and temperature difference in four patch phase increased significantly, and average air temperature and average soil temperature significantly decreased. The spatio-temporal heterogeneity of ecological factors in different patch types in forest cycle provided a basis to maintain the coexistence of different species with different characteristics within forest community.

3

Recruitment pattern of tree populations along an altitudinal gradient: Larix chinensis Beissn in Qinling Mountains [China]

75%

Duan R. Y. , Wang X.-A. , Tu Y.-B. , Huang M.-Y. , Wang C. , Zhu Z.-H. , Guo H.

Polish Journal of Ecology

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2009

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tom 57

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nr 3

451-459

EN

Larix chinensis Beissn is an endangered plant found only in the Qinling Mountains, Shaanxi, northwestern China. It is densely distributed in the alpine and subalpine belt on their highest peak Taibai Mountain. Age structure studies along a montane altitudinal gradient would be helpful in understanding the limiting factors on the regeneration of natural forests. The forest was divided into three transects, i.e., lower limit (2900–3000 m), mid-altitude (3100–3200 m) and upper limit (3300–3400 m). The age structures differed across altitude classes. The age structure in the low altitude transect was closed to bell-shaped and characterized by the dominance of adult trees. A reverse-J shape age structure was found in the mid-altitude transect. Multi-modal age distribution was found in the high altitude transect, and was caused by lack of young seedlings and saplings. This suggests that different limiting factors play important roles in shaping the age structure and forest regeneration at different altitudes. In the low altitude, light availability was probably the most important limiting factor. In the mid-altitudinal transect, density dependent intraspecific competition between trees likely controlled regeneration of L. chinensis. We suggest that limiting climatic factors, e.g. temperature, play an important role in determining the age structure of L. chinensis populations in highaltitude areas.