Nonlinear characteristics of the vegetation change and its response to climate change in the karst region of southwest China

Author(s):  
Mingyang Zhang ◽  
Zhenhua Deng ◽  
Yuemin Yue ◽  
Kelin Wang ◽  
Huiyu Liu ◽  
...  

The vegetation is known to be sensitive to both climate change and anthropogenic disturbance. However, the relationship between changes in vegetation and climate is unclear in karst regions. The nonlinear characteristics of vegetation change and its possible relationships with driving factors in the karst region of southwest China are revealed, using methods of Ensemble Empirical Mode Decomposition, Mann-Kendall, and Partial Least Squares Regression. The results show that: (1) vegetation changes demonstrate an increasing trend with an abrupt change in 2002. Multiple time scales of 3, 6, 10, and 25-year are observed in vegetation variations, dominated by long-term trend and the short time scale of 3-year with variance contributions of 58.10% and 28.63%. (2) The relationship of climate indexes with vegetation changes shows r2 = 0.78 ( p < 0.01) based on the reconstruction of characteristic scales, indicating significant great relationship. In space, the area percentage with relationship of climate to vegetation is more than 50%, and the impact is much greater after the abrupt change of vegetation in 2002 ( r2 are 0.24–0.91 and 0.42–0.99, respectively). In addition, the correlation between vegetation change and ecological engineering is 0.15 ( p < 0.01). The results indicate that climate change is the main impact factor of vegetation change, ecological engineering has positive influences in improving vegetation condition, and methods of scales decomposition and abrupt detection could reveal some hidden information for better understanding ecosystems in karst regions.

2019 ◽  
Vol 11 (13) ◽  
pp. 1564 ◽  
Author(s):  
Xiaojuan Xu ◽  
Huiyu Liu ◽  
Zhenshan Lin ◽  
Fusheng Jiao ◽  
Haibo Gong

Vegetation is known to be sensitive to both climate change and anthropogenic disturbance in the karst region. However, the relationship between an abrupt change in vegetation and its driving factors is unclear at multiple timescales. Based on the non-parametric Mann-Kendall test and the ensemble empirical mode decomposition (EEMD) method, the abrupt changes in vegetation and its possible relationships with the driving factors in the karst region of southwest China during 1982–2015 are revealed at multiple timescales. The results showed that: (1) the Normalized Difference Vegetation Index (NDVI) showed an overall increasing trend and had an abrupt change in 2001. After the abrupt change, the greening trend of the NDVI in the east and the browning trend in the west, both changed from insignificant to significant. (2) After the abrupt change, at the 2.5-year time scale, the correlation between the NDVI and temperature changed from insignificantly negative to significantly negative in the west. Over the long-term trend, it changed from significantly negative to significantly positive in the east, but changed from significantly positive to significantly negative in the west. The abrupt change primarily occurred on the long-term trend. (3) After the abrupt change, 1143.32 km2 farmland was converted to forests in the east, and the forest area had significantly increased. (4) At the 2.5-year time scale, the abrupt change in the relationships between the NDVI and climate factors was primarily driven by climate change in the west, especially rising temperatures. Over the long-term trend, it was caused by ecological protection projects in the east, but by rising temperatures in the west. The integration of the abrupt change analysis and multiple timescale analysis help assess the relationship of vegetation changes with climate changes and human activities accurately and comprehensively, and deepen our understanding of the driving mechanism of vegetation changes, which will further provide scientific references for the protection of fragile ecosystems in the karst region.


2009 ◽  
Vol 45 (No. 4) ◽  
pp. 155-159 ◽  
Author(s):  
X.Z. Liu ◽  
C.S. He ◽  
Y.M. Yang ◽  
H.Y. Zhang

AFLP analyses were used to assess the genetic similarity among selected accessions at the South China Tobacco Breeding Research Centre (Yunnan province, Southwest China). 154 AFLP polymorphic fragments out of 561 fragments were used to assess the genetic diversity among 28 tobacco accessions. The average number of polymorphic bands per AFLP primer pair was 15.4. AFLPs seemed to be an effective classification tools for germplasm conservation and breeding. Limited genetic variation was detected within this group of accessions. The relationship of cultivars was estimated by cluster analysis based on AFLP data.


2008 ◽  
Vol 160 (1-4) ◽  
pp. 157-168 ◽  
Author(s):  
Yuemin Yue ◽  
Kelin Wang ◽  
Bing Zhang ◽  
Zhengchao Chen ◽  
Quanjun Jiao ◽  
...  

2020 ◽  
Author(s):  
Wei Yuan ◽  
Shuang-ye Wu ◽  
Shugui Hou

&lt;p&gt;This study aims to establish future vegetation changes in the east and central of northern China (ECNC), an ecologically sensitive region in the transition zonal from humid monsoonal to arid continental climate. The region has experienced significant greening in the past several decades. However, few studies exist on how vegetation will change with future climate change, and great uncertainties exist due to complex, and often spatially non-stationary, relationships between vegetation and climate. In this study, we first used historical NDVI and climate data to model this spatially variable relationship with Geographically Weighted Logit Regression. We found that temperature and precipitation could explain, on average, 43% of NDVI variance, and they could be used to&amp;#160;model NDVI fairly well. We then establish future climate change using the output of 11 CMIP6 models for the medium (SSP245) and high (SSP585) emission scenarios for the mid-century (2041-2070) and late-century (2071-2100). The results show that for this region, both temperature and precipitation will increase under both scenarios. By late-century under SSP585, precipitation is projected to increase by 25.12% and temperature is projected to increase 5.87&lt;sup&gt;o&lt;/sup&gt;C in ECNC. Finally, we used future climate conditions as input for the regression models to project future vegetation (indicated by NDVI). We found that NDVI will increase under climate change. By mid-century, the average NDVI in ECNC will increase by 0.024 and 0.021 under SSP245 and SSP585. By late-century, it will increase by 0.016 and 0.006 under SSP245 and SSP585&amp;#160;respectively. Although NDVI is projected to increase, the magnitude of increase is likely to diminish with higher emission scenarios, possibly due to the benefit of precipitation increase being gradually encroached by the detrimental effects of temperature increase. Moreover, despite the overall NDVI increase, the area likely to suffer vegetation degradation will also expands, particularly in the western part of ECNC. With higher emissions and later into the century, region with low NDVI is likely to shift and/or expand north-forward. Our results could provide important information on possible&amp;#160;vegetation changes, which could help to develop effective management strategies to ensure ecological and economic sustainability&amp;#160;in the future.&lt;/p&gt;


2013 ◽  
Vol 2013 (1) ◽  
pp. 4982
Author(s):  
Hwanjin Park ◽  
Jaechul Song ◽  
Jaeyoung Kim ◽  
Inah Kim ◽  
Clara Tammy Kim

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Sumi Na ◽  
Eunyoung Lee ◽  
Hyunjung Kim ◽  
Seiwoong Choi ◽  
Hoonbok Yi

Abstract Background Organism body size is a basic characteristic in ecology; it is related to temperature according to temperature-size rule. Butterflies are affected in various aspects by climate change because they are sensitive to temperature. Therefore, this study was conducted to understand the effect of an increase in temperature due to global warming on the wing of butterflies. Results A total of 671 butterflies belonging to 9 species were collected from 1990 to 2016 in Seoul (336 specimens) and Mokpo (335 specimens). Consequently, as the mean temperature increased, the wing length of the species increased. However, there are exceptions that the Parnassius stubbendorfii, Pieridae canidia, and Pieris rapae wing length of Seoul increased, but the butterfly wing length of Mokpo decreased. Conclusions The positive correlations between the butterfly wing length and mean temperature showed that the change of mean temperature for about 26 years affects the wing length of butterfly species. The exception is deemed to have been influenced by the limited research environment, and further studies are needed. We would expect that it can be provided as basic data for studying effect of climate change.


Climate ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 148
Author(s):  
Mélanie Doyon ◽  
Juan-Luis Klein

The objective of this text is to present a reflection on the link between local initiatives to combat food insecurity and actions adapting to climate change. To this end, two case studies of ongoing experiments in the Canadian province of Quebec will be presented and compared. While these two cases are very different in terms of location, production and people involved, they share the objective of bringing fresh and healthy food, produced locally, to the population of their territory and of rethinking the relationship of the community to nature through food production. Despite their significant differences, each of these two cases features actions for responding to problems that have a common cause: an agro-industrial food system that, by decoupling the locations of production and consumption, in order to maximize the economic profitability of the capital invested, has compromised both the health of citizens and the ecological balance.


2020 ◽  
Vol 12 (24) ◽  
pp. 4035
Author(s):  
Xiaohui Zhai ◽  
Xiaolei Liang ◽  
Changzhen Yan ◽  
Xuegang Xing ◽  
Haowei Jia ◽  
...  

In recent decades, the vegetation of the Sanjiangyuan region has undergone a series of changes under the influence of climate change, and ecological restoration projects have been implemented. In this paper, we analyze the spatiotemporal dynamics of vegetation in this region using the satellite-retrieved normalized difference vegetation index (NDVI) from the global inventory modeling and mapping studies (GIMMS) and moderate resolution imaging and spectroradiometer (MODIS) datasets during the past 34 years. Specifically, the characteristics of vegetation changes were analyzed according to the stage of implementation of different ecological engineering programs. The results are as follows. (1) The vegetation in 65.6% of the study area exhibited an upward trend, and in 53.0% of the area, it displayed a large increase, which was mainly distributed in the eastern part of the study area. (2) The vegetation NDVI increased to differing degrees during stages of ecological engineering. (3) The NDVI in the western part of the Sanjiangyuan region is mainly affected by temperature, while in the northeastern part, the NDVI is affected more by precipitation. In the southern part, however, vegetation growth is affected neither by temperature nor by precipitation. On the whole region, vegetation growing is more affected by temperature than by precipitation. (4) The impacts of human activities on vegetation change are both positive and negative. In recent years, ecological engineering projects have had a positive impact on vegetation growth. This study can help us to correctly understand the impact of climate change on vegetation growth, so as to provide a scientific basis for the evaluation of regional ecological engineering effectiveness and the formulation of ecological protection policies.


2019 ◽  
Vol 11 (17) ◽  
pp. 2044 ◽  
Author(s):  
Jie Pei ◽  
Li Wang ◽  
Xiaoyue Wang ◽  
Zheng Niu ◽  
Maggi Kelly ◽  
...  

Since the implementation of China’s afforestation and conservation projects during recent decades, an increasing number of studies have reported greening trends in the karst regions of southwest China using coarse-resolution satellite imagery, but small-scale changes in the heterogenous landscapes remain largely unknown. Focusing on two typical karst regions in the Nandong and Xiaojiang watersheds in Yunnan province, we processed 2,497 Landsat scenes from 1988 to 2016 using the Google Earth Engine cloud platform and analyzed vegetation trends and associated drivers. We found that both watersheds experienced significant increasing trends in annual fractional vegetation cover, at a rate of 0.0027 year−1 and 0.0020 year−1, respectively. Notably, the greening trends have been intensifying during the conservation period (2001–2016) even under unfavorable climate conditions. Human-induced ecological engineering was the primary factor for the increased greenness. Moreover, vegetation change responded differently to variations in topographic gradients and lithological types. Relatively more vegetation recovery was found in regions with moderate slopes and elevation, and pure limestone, limestone and dolomite interbedded layer as well as impure carbonate rocks than non-karst rocks. Partial correlation analysis of vegetation trends and temperature and precipitation trends suggested that climate change played a minor role in vegetation recovery. Our findings contribute to an improved understanding of the mechanisms behind vegetation changes in karst areas and may provide scientific supports for local afforestation and conservation policies.


Author(s):  
Anna Burton ◽  
Oliver Fritz ◽  
Ulrike Pröbstl-Haider ◽  
Kathrin Ginner ◽  
Herbert Formayer

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