The Experts below are selected from a list of 11304 Experts worldwide ranked by ideXlab platform
Yuanming Zhang - One of the best experts on this subject based on the ideXlab platform.
-
relationship of species diversity between Overstory trees and understory herbs along the environmental gradients in the tianshan wild fruit forests northwest china
Journal of Arid Land, 2020Co-Authors: Junhui Cheng, Xiaojun Shi, Pengrui Fan, Xiaobing Zhou, Jiandong Sheng, Yuanming ZhangAbstract:In forest ecosystems, interactions between Overstory trees and understory herbs play an important role in driving plant species diversity. However, reported links between Overstory tree and understory herb species diversity have been inconsistent, due to variations in forest types and environmental conditions. Here, we measured species richness (SR) and diversity (Shannon-Wiener (H') and Simpson's (D) indices) of Overstory trees and understory herbs in the protected Tianshan Wild Fruit Forest (TWFF), Northwest China, to explore their relationships along the latitudinal, longitudinal, elevational, and climatic (current climate and paleoclimate) gradients in 2018. We found that SR, and H' and D diversity indices of Overstory trees and understory herbs exhibited a unimodal pattern with increasing latitude and elevation (P<0.05) and negative associations with longitude (P<0.01). Along the climatic gradients, there were U-shaped patterns in SR, and H' and D diversity indices between trees and herbs (P<0.05). SR, and H' and D diversity indices for Overstory tree species were positively associated with those for understory herbs (P<0.01). These findings indicate that Overstory trees and understory herbs should be protected concurrently in the TWFF to increase effectiveness of species diversity conservation programs.
-
Relationship of species diversity between Overstory trees and understory herbs along the environmental gradients in the Tianshan Wild Fruit Forests, Northwest China
Journal of Arid Land, 2020Co-Authors: Junhui Cheng, Xiaojun Shi, Pengrui Fan, Xiaobing Zhou, Jiandong Sheng, Yuanming ZhangAbstract:In forest ecosystems, interactions between Overstory trees and understory herbs play an important role in driving plant species diversity. However, reported links between Overstory tree and understory herb species diversity have been inconsistent, due to variations in forest types and environmental conditions. Here, we measured species richness (SR) and diversity (Shannon-Wiener (H') and Simpson's (D) indices) of Overstory trees and understory herbs in the protected Tianshan Wild Fruit Forest (TWFF), Northwest China, to explore their relationships along the latitudinal, longitudinal, elevational, and climatic (current climate and paleoclimate) gradients in 2018. We found that SR, and H' and D diversity indices of Overstory trees and understory herbs exhibited a unimodal pattern with increasing latitude and elevation (P
Nils Rydberg - One of the best experts on this subject based on the ideXlab platform.
-
The influence of different Overstory removal on planted spruce and several broadleaved tree species: Survival, growth and pine weevil damage during three years
Annals of Forest Science, 2005Co-Authors: Robert Magnus Löf, Dan Paulsson, Nils RydbergAbstract:The influence of different Overstory removal on herbivory by the pine weevil to seedlings was studied in a field experiment. Four Overstory treatments with middle aged Norway spruce in combination with or without insecticide treatments were applied. Seedlings of the following seven tree species were planted in each of the four blocks: Acer platanoides L., Fagus sylvatica L., Fraxinus excelsior L., Picea abies L. (Karst.), Prunus avium L., Quercus robur L. and Tilia cordata Mill. The seedlings were monitored through the 2001-2003 growing seasons. Highest survival was found among seedlings planted in the Overstory treatments with 15 and 20% light in the understory, whereas best diameter growth in seedlings was found in the clearcut. Overstory trees of Norway spruce decreased herbivory from pine weevil considerably among underplanted seedlings, and the pine weevils fed significantly more on planted Norway spruce seedlings than on all broadleaved tree species. The following rough preference order was obtained: (1) Norway spruce >> (2) beech and oak > (3) ash, cherry, lime and maple. The influence from the insecticide treatment was minor. Therefore, during the conversion of Norway spruce monocultures into mixed species stands using overstories, the use of insecticides against pine weevil is not needed.
Katherine J. Elliott - One of the best experts on this subject based on the ideXlab platform.
-
Functional Role of the Herbaceous Layer in Eastern Deciduous Forest Ecosystems
Ecosystems, 2015Co-Authors: Katherine J. Elliott, James M. Vose, Jennifer D. Knoepp, Barton D. Clinton, Brian D. KloeppelAbstract:The importance of the herbaceous layer in regulating ecosystem processes in deciduous forests is generally unknown. We use a manipulative study in a rich, mesophytic cove forest in the southern Appalachians to test the following hypotheses: (i) the herbaceous functional group (HFG) in mesophytic coves accelerates carbon and nutrient cycling, (ii) high litter quality input and rapid nutrient turnover associated with HFG will have a positive effect on Overstory tree growth, and (iii) the HFG regulates tree regeneration with negative effects on seedling establishment due to competition for resources. We established treatment plots in a mesic, cove-hardwoods forest and removed the herbaceous flora (HR, removed twice per year) or added herbaceous organic material (OMA, once per year) for comparison to a no removal (NR) reference for a total of 14 years. The OMA treatment stimulated soil N-mineralization and increased litterfall mass and N content. OMA N-mineralization rates were more than two times greater than both the NR and HR treatments; however, we did not detect significant differences in soil CO_2 efflux among treatments. Higher Overstory litterfall mass and N in the OMA treatment plots indicated that Overstory trees were benefiting from the enhanced soil N-mineralization. Higher Overstory leaf mass and N suggests an important linkage between HR and aboveground net primary production even though this did not translate into greater tree basal area increment. We found an increase in regeneration of all tree species with HFG removal, and the response was particularly evident for Acer rubrum seedlings.
-
Long-Term Effects of High Intensity Prescribed Fire on Vegetation Dynamics in the Wine Spring Creek Watershed, Western North Carolina, USA
Fire Ecology, 2009Co-Authors: Katherine J. Elliott, James M. Vose, Ronald L. HendrickAbstract:We examined the long-term effects of a prescribed fire in a southern Appalachian watershed in Nantahala National Forest, western North Carolina, USA. Fire was prescribed in 1995 on this site by forest managers to restore a degraded pine ( Pinus spp.)-hardwood community, specifically to stimulate forage production, promote pine and oak ( Quercus spp.) regeneration, and increase plant diversity. Before and after the prescribed fire, permanent plots were sampled across a south-facing hillslope, which corresponded to three community types: mesic, near-stream cove (riparian); dry, mixed-oak (mid-slope); and xeric, pine-hardwood (ridge). In an earlier paper, we reported the first two years of post-burn vegetation response from this prescribed burn. In our current study, we compared the pre-burn (1994) forest condition with 10 years post-burn (2005) vegetation measurements to determine the effects of fire on the mortality and regeneration of Overstory trees, understory shrubs, and herbaceous-layer species. Overstory mortality was high immediately after the burn at the ridge location and ten years after the fire. Mortality of pitch pine ( Pinus rigida Miller) (91.8 %) and hickory ( Carya spp.) (77.5 %) reduced Overstory basal area from 26.97 m^2 ha^−1 pre-burn to 18.86 m^2 ha^−1 post-burn in 1995 and to 9.13 m^2 ha^−1 in 2005. At the mid-slope and riparian locations, no significant Overstory mortality occurred over time. Understory density was significantly higher 10 years after the burn (2005) than pre-burn, and basal area had returned to pre-burn levels. Density of mountain laurel ( Kalmia latifolia L.), black huckleberry ( Gaylussacia baccata [Wang.] K. Koch), and blueberry ( Vaccinium spp.) had increased due to prolific sprouting. The prescribed fire had varying effects on diversity across the hillslope gradient over time. On the ridge, Overstory diversity declined following the fire (H’_basal area = 1.14 in 1994, H’_basal area = 0.75 in 1995, and H’_basal area = 0.80 in 2005). Diversity significantly increased in the herbaceous layer and remained higher than pre-burn conditions through 2005 (H’_cover = 1.02 in 1994, H’_cover = 1.97 in 1995, and H’_cover = 2.25 in 2005). For the mid-slope and riparian positions, no change in diversity was observed in the Overstory, understory or herbaceous layer.
-
vegetation dynamics after a prescribed fire in the southern appalachians
Forest Ecology and Management, 1999Co-Authors: Katherine J. Elliott, James M. Vose, Ronald L. Hendrick, Amy E Major, Wayne T SwankAbstract:Abstract In April 1995, the USDA Forest Service conducted a prescribed burn along with a south-facing slope of southern Appalachian watershed, Nantahala National Forest, western NC. Fire had been excluded for over 70 years and the purpose of the burn was to create a mosaic of fire intensities to restore a degraded pine/hardwood community and to stimulate forage production and promote oak regeneration along a hillslope gradient. Permanent plots were sampled at three locations along a gradient from 1500 to 1700 m. Plot locations corresponded to three community types: mesic, near-riparian cove (low slope); dry, mixed-oak (mid slope); and xeric, pine/hardwood (ridge). Before burning (1994–1995) and post-burn (summer, 1995 and summer, 1996) vegetation measurements were used to determine the effects of fire on the mortality and regeneration of Overstory trees, understory shrubs, and herbaceous species. After the burn, mortality was highest (31%) at the ridge location, substantially reducing Overstory (from 26.84 pre-burn to 19.05 m2 ha−1 post-burn) and understory shrub (from 6.52 pre-burn to 0.37 m2 ha−1 post-burn) basal area. At the mid-slope position, mortality was only 3%, and no mortality occurred at the low slope. Not surprisingly, percent mortality corresponded to the level of fire intensity. Basal area of Kalmia latifolia, Gaylussacia baccata, and Vaccinium spp. were substantially reduced after the fire, but density increased due to prolific sprouting. The prescribed fire had varying effects on species richness and diversity across the hillslope gradient. On the ridge, diversity was significantly increased in the understory and herb-layer, but decreased in the Overstory. On the mid slope, no change was observed in the Overstory, but diversity significantly decreased in the understory. On the low slope, no change was observed in the Overstory or understory.
Junhui Cheng - One of the best experts on this subject based on the ideXlab platform.
-
relationship of species diversity between Overstory trees and understory herbs along the environmental gradients in the tianshan wild fruit forests northwest china
Journal of Arid Land, 2020Co-Authors: Junhui Cheng, Xiaojun Shi, Pengrui Fan, Xiaobing Zhou, Jiandong Sheng, Yuanming ZhangAbstract:In forest ecosystems, interactions between Overstory trees and understory herbs play an important role in driving plant species diversity. However, reported links between Overstory tree and understory herb species diversity have been inconsistent, due to variations in forest types and environmental conditions. Here, we measured species richness (SR) and diversity (Shannon-Wiener (H') and Simpson's (D) indices) of Overstory trees and understory herbs in the protected Tianshan Wild Fruit Forest (TWFF), Northwest China, to explore their relationships along the latitudinal, longitudinal, elevational, and climatic (current climate and paleoclimate) gradients in 2018. We found that SR, and H' and D diversity indices of Overstory trees and understory herbs exhibited a unimodal pattern with increasing latitude and elevation (P<0.05) and negative associations with longitude (P<0.01). Along the climatic gradients, there were U-shaped patterns in SR, and H' and D diversity indices between trees and herbs (P<0.05). SR, and H' and D diversity indices for Overstory tree species were positively associated with those for understory herbs (P<0.01). These findings indicate that Overstory trees and understory herbs should be protected concurrently in the TWFF to increase effectiveness of species diversity conservation programs.
-
Relationship of species diversity between Overstory trees and understory herbs along the environmental gradients in the Tianshan Wild Fruit Forests, Northwest China
Journal of Arid Land, 2020Co-Authors: Junhui Cheng, Xiaojun Shi, Pengrui Fan, Xiaobing Zhou, Jiandong Sheng, Yuanming ZhangAbstract:In forest ecosystems, interactions between Overstory trees and understory herbs play an important role in driving plant species diversity. However, reported links between Overstory tree and understory herb species diversity have been inconsistent, due to variations in forest types and environmental conditions. Here, we measured species richness (SR) and diversity (Shannon-Wiener (H') and Simpson's (D) indices) of Overstory trees and understory herbs in the protected Tianshan Wild Fruit Forest (TWFF), Northwest China, to explore their relationships along the latitudinal, longitudinal, elevational, and climatic (current climate and paleoclimate) gradients in 2018. We found that SR, and H' and D diversity indices of Overstory trees and understory herbs exhibited a unimodal pattern with increasing latitude and elevation (P
Qing Zhou - One of the best experts on this subject based on the ideXlab platform.
-
response of foliar functional traits to experimental n and p addition among Overstory and understory species in a tropical secondary forest
Global Ecology and Conservation, 2020Co-Authors: Wenjuan Wang, Yiqun Chen, Zhongtong Peng, Qing ZhouAbstract:Abstract The plasticity of morphological, physiological and developmental traits can reflect the plant adaptation to diverse environmental changes. How the foliar morphological and physiological traits with different functional groups in response to N and P fertilization is still unclear in tropical forests. Here, we employed a nine-year manipulative field experiment with nitrogen (N) and phosphorus (P) addition to investigate the foliar morphological and physiological traits as well as the N and P stoichiometry within the Overstory and understory species in a tropical secondary forest of southern China. Our results showed that the N and P addition did not significantly change leaf morphological traits (leaf length, width, and ratios of length:width, leaf mass per area, LMA) in most of the studied species. The effects of N and/or P addition on leaf photosynthetic pigments were species-specific variation regardless of the Overstory and understory species. However, the leaf N:P ratios of two understory species were significantly influenced by P addition while leaf N:P ratios in all Overstory plants were not affected by P fertilization. Combined with the change of leaf N:P ratios under nine-year fertilization experiment, the understory plants were primarily limited by P availability, while the overstroy trees were co-limited by N and P availability in this tropical forest. Given that, we recommend that the constant leaf morphological traits of Overstory and understory species in response to exogenous long-term N and P addition may be an important mechanism for adapting to low-P availability soil.
