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Dandan Zhao
School of Tourism and Geography Science, Jilin Normal University, Siping 136000, China

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Journal article
Published: 26 January 2020 in Sustainability
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Climate change and human activities are important factors driving changes in wetland ecosystems. It is therefore crucial to quantitatively characterize the relative importance of these stressors in wetlands. Previous such analyses have generally not distinguished between wetland types, or have focused on individual wetland types. In this study, three representative wetland areas of the upper, middle and lower reaches of the Heilongjiang River Basin (HRB) were selected as the study area. An object-based classification was used with Landsat TM data to extract the spatial distribution of wetland in 1990, 2000 and 2010. We then quantified the relative importance of climate change and human activities on the wetlands by using the R package “relaimpo” package. The results indicated that: (1) the effects of human activities on wetland changes were greater (contribution rate of 63.57%) than climate change in the HRB. Specifically, there were differences in the relative importance of climate change and human activities for wetlands in different regions. Wetlands of the upper reaches were more affected by climate change, while wetlands in the middle and lower reaches were more affected by human activities; (2) climate change had a greater impact (contribution rate of 65.72%) on low intensity wetland loss, while human activities had a greater impact on moderate and severe intensity wetland loss, with respective contribution rates of 57.22% and 70.35%; (3) climate change had a larger effect on the shrub and forested wetland changes, with respective contribution rates of 58.33% and 52.58%. However, human activities had a larger effect on herbaceous wetland changes, with a contribution rate of 72.28%. Our study provides a useful framework for wetland assessment and management, and could be a useful tool for developing wetland utilization and protection approaches, particularly in sensitive environments in mid- and high-latitude areas.

ACS Style

Yongcai Dang; Hongshi He; Dandan Zhao; Michael Sunde; Haibo Du. Quantifying the Relative Importance of Climate Change and Human Activities on Selected Wetland Ecosystems in China. Sustainability 2020, 12, 912 .

AMA Style

Yongcai Dang, Hongshi He, Dandan Zhao, Michael Sunde, Haibo Du. Quantifying the Relative Importance of Climate Change and Human Activities on Selected Wetland Ecosystems in China. Sustainability. 2020; 12 (3):912.

Chicago/Turabian Style

Yongcai Dang; Hongshi He; Dandan Zhao; Michael Sunde; Haibo Du. 2020. "Quantifying the Relative Importance of Climate Change and Human Activities on Selected Wetland Ecosystems in China." Sustainability 12, no. 3: 912.

Journal article
Published: 16 February 2019 in Forests
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Alpine plant communities are highly sensitive to global warming. One of the consequences of the warming is encroachment by herbaceous plants from forests at low elevations into alpine ecosystems. In the Changbai Mountains, narrowleaf small reed (Deyeuxia angustifolia (Kom.) Y. L. Chang) from mountain birch forests encroached upward into alpine tundra, gradually replacing native tundra shrubs such as Rhododendron (Rhododendron aureum Georgi). How encroaching plants affect native plant communities is not fully understood. In this study, we analyzed above- and belowground biomass of alpine plant communities at five encroachment levels to investigate how biomass allocation changed at species and community scales. Our research showed that native plants are forced to change their morphology to cope with competition, at both above- and belowground levels, from encroaching plants. We found that (1) R. aureum increased the shoot height and leaf area in order to compete with D. angustifolia; (2) above- and belowground biomass of D. angustifolia increased while above- and belowground biomass of R. aureum decreased with increasing levels of encroachment; and (3) D. angustifolia encroachment reduced the total biomass of alpine tundra. Encroachment by herbaceous plants has a long-term negative impact on the ability of tundra plants to sequester carbon in the alpine tundra of the Changbai Mountains.

ACS Style

Xinyuan Tan; Hong S. He; Shengwei Zong; Miaomiao Wu; Kai Liu; Dandan Zhao. Herbaceous Encroachment from Mountain Birch Forests to Alpine Tundra Plant Communities Through Above- and Belowground Competition. Forests 2019, 10, 170 .

AMA Style

Xinyuan Tan, Hong S. He, Shengwei Zong, Miaomiao Wu, Kai Liu, Dandan Zhao. Herbaceous Encroachment from Mountain Birch Forests to Alpine Tundra Plant Communities Through Above- and Belowground Competition. Forests. 2019; 10 (2):170.

Chicago/Turabian Style

Xinyuan Tan; Hong S. He; Shengwei Zong; Miaomiao Wu; Kai Liu; Dandan Zhao. 2019. "Herbaceous Encroachment from Mountain Birch Forests to Alpine Tundra Plant Communities Through Above- and Belowground Competition." Forests 10, no. 2: 170.

Journal article
Published: 05 December 2018 in Forests
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The vegetation of alpine tundra is undergoing significant changes and topography has played a significant role in mediating such changes. The roles of topography varied at different scales. In this study, we intended to identify topographic controls on tundra vegetation changes within the Changbai Mountains of Northeast China and reveal the scale effects. We delineated the vegetation changes of the last three decades using the normalized difference vegetation index (NDVI) time series. We conducted a trend analysis for each pixel to reveal the spatial change and used binary logistic regression models to analyze the relationship between topographic controls at different scales and vegetation changes. Results showed that about 30% of tundra vegetation experienced a significant (p < 0.05) change in the NDVI, with 21.3% attributable to the encroachment of low-altitude plants resulting in a decrease in the NDVI, and 8.7% attributable to the expansion of tundra endemic plants resulting in an increase in the NDVI. Plant encroachment occurred more severely in low altitude than in high altitude, whereas plant expansion mostly occurred near volcanic ash fields at high altitude. We found that plant encroachment tended to occur in complex terrains and the broad-scale mountain aspect had a greater effect on plant encroachment than the fine-scale local aspect. Our results suggest that it is important to include the mountain aspect in mountain vegetation change studies, as most such studies only use the local aspect.

ACS Style

Miaomiao Wu; Hong S. He; Shengwei Zong; Xinyuan Tan; Haibo Du; Dandan Zhao; Kai Liu; Yu Liang. Topographic Controls on Vegetation Changes in Alpine Tundra of the Changbai Mountains. Forests 2018, 9, 756 .

AMA Style

Miaomiao Wu, Hong S. He, Shengwei Zong, Xinyuan Tan, Haibo Du, Dandan Zhao, Kai Liu, Yu Liang. Topographic Controls on Vegetation Changes in Alpine Tundra of the Changbai Mountains. Forests. 2018; 9 (12):756.

Chicago/Turabian Style

Miaomiao Wu; Hong S. He; Shengwei Zong; Xinyuan Tan; Haibo Du; Dandan Zhao; Kai Liu; Yu Liang. 2018. "Topographic Controls on Vegetation Changes in Alpine Tundra of the Changbai Mountains." Forests 9, no. 12: 756.

Journal article
Published: 25 September 2018 in International Journal of Environmental Research and Public Health
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Forest swamps are widely distributed in cold temperate regions, with important landscape and ecological functions. They are prone to conversion caused by complex factors. Forest swamp conversions involve forest swamping, meadow swamping, water body swamping, and conversion to farmland. An understanding of the landscape characteristics and primary environmental factors driving forest swamp conversions is imperative for exploring the mechanism of forest swamp conversions. We investigated the landscape characteristics of forest swamp conversions and quantified the relative importance of environmental factors driving these conversions for the period from 1990 to 2015 in the Great Xing’an Mountains of China. We found that forest swamping displayed high patch numbers (34,916) and density (8.51/100 ha), commonly occurring at the edge of large areas of forests. Meadow swamping was localized with low patch numbers (3613) and density (0.88/100 ha) due to lack of water recharge from ground water. Water body swamping had complex shapes (perimeter area ratio mean = 348.32) because of water table fluctuations and helophyte growth during this conversion process. Conversions to farmland presented fairly regular (perimeter area ratio mean = 289.91) and aggregated (aggregation index = 67.82) characteristics affected by agricultural irrigation and management. We found that climatic and geomorphic factors were relatively important compared to topographic factors for forest swamp conversions. Negative geomorphic conditions provided the waterlogging environment as a precondition of swamp formation. Sufficient precipitation was an important source of water recharge due to the existence of permafrost regions and long-term low temperature reduced the evaporation of swamps water and the decomposition rate of organisms. These wet and cold climatic conditions promoted forest swamp development in cold temperate regions. Humans exerted a relatively important role in forest swamping and conversions to farmland. Fire disturbance and logging accelerated the conversion from forest to swamp. This study provides scientific information necessary for the management and conservation of forest swamp resources in cold temperate regions.

ACS Style

Dandan Zhao; Hong S. He; Wen J. Wang; Jiping Liu; Haibo Du; Miaomiao Wu; Xinyuan Tan. Distribution and Driving Factors of Forest Swamp Conversions in a Cold Temperate Region. International Journal of Environmental Research and Public Health 2018, 15, 2103 .

AMA Style

Dandan Zhao, Hong S. He, Wen J. Wang, Jiping Liu, Haibo Du, Miaomiao Wu, Xinyuan Tan. Distribution and Driving Factors of Forest Swamp Conversions in a Cold Temperate Region. International Journal of Environmental Research and Public Health. 2018; 15 (10):2103.

Chicago/Turabian Style

Dandan Zhao; Hong S. He; Wen J. Wang; Jiping Liu; Haibo Du; Miaomiao Wu; Xinyuan Tan. 2018. "Distribution and Driving Factors of Forest Swamp Conversions in a Cold Temperate Region." International Journal of Environmental Research and Public Health 15, no. 10: 2103.

Journal article
Published: 19 March 2018 in Sustainability
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Wetlands in the mid- and high-latitudes are particularly vulnerable to environmental changes and have declined dramatically in recent decades. Climate change and human activities are arguably the most important factors driving wetland distribution changes which will have important implications for wetland ecological functions and services. We analyzed the importance of driving variables for wetland distribution and investigated the relative importance of climatic factors and human activity factors in driving historical wetland distribution changes. We predicted wetland distribution changes under climate change and human activities over the 21st century using the Random Forest model in a mid- and high-latitude region of Northeast China. Climate change scenarios included three Representative Concentration Pathways (RCPs) based on five general circulation models (GCMs) downloaded from the Coupled Model Intercomparison Project, Phase 5 (CMIP5). The three scenarios (RCP 2.6, RCP 4.5, and RCP 8.5) predicted radiative forcing to peak at 2.6, 4.5, and 8.5 W/m2 by the 2100s, respectively. Our results showed that the variables with high importance scores were agricultural population proportion, warmness index, distance to water body, coldness index, and annual mean precipitation; climatic variables were given higher importance scores than human activity variables on average. Average predicted wetland area among three emission scenarios were 340,000 ha, 123,000 ha, and 113,000 ha for the 2040s, 2070s, and 2100s, respectively. Average change percent in predicted wetland area among three periods was greatest under the RCP 8.5 emission scenario followed by RCP 4.5 and RCP 2.6 emission scenarios, which were 78%, 64%, and 55%, respectively. Losses in predicted wetland distribution were generally around agricultural lands and expanded continually from the north to the whole region over time, while the gains were mostly associated with grasslands and water in the most southern region. In conclusion, climatic factors had larger effects than human activity factors on historical wetland distribution changes and wetland distributions were predicted to decline remarkably over time under climate change scenarios. Our findings have important implications for wetland resource management and restoration because predictions of future wetland changes are needed for wetlands management planning.

ACS Style

Dandan Zhao; Hong He; Wen Wang; Lei Wang; Haibo Du; Kai Liu; Shengwei Zong. Predicting Wetland Distribution Changes under Climate Change and Human Activities in a Mid- and High-Latitude Region. Sustainability 2018, 10, 863 .

AMA Style

Dandan Zhao, Hong He, Wen Wang, Lei Wang, Haibo Du, Kai Liu, Shengwei Zong. Predicting Wetland Distribution Changes under Climate Change and Human Activities in a Mid- and High-Latitude Region. Sustainability. 2018; 10 (3):863.

Chicago/Turabian Style

Dandan Zhao; Hong He; Wen Wang; Lei Wang; Haibo Du; Kai Liu; Shengwei Zong. 2018. "Predicting Wetland Distribution Changes under Climate Change and Human Activities in a Mid- and High-Latitude Region." Sustainability 10, no. 3: 863.