Do Extreme Climate Events Cause the Degradation of Malus sieversii Forests in China?

Frequent extreme climate events have attracted considerable attention around the world. Malus sieversii in Xinjiang is the ancestor of cultivated apple, and it is mainly distributed in the Ili river valley at end of the Tianshan Mountains. Wild fruit forests have been degraded, but the cause remains unclear. In order to identify whether extreme climate events caused this degradation reanalysis data and atmospheric circulation indices were used to determine the trends and the reasons for extreme climate changes. Subsequently, we further investigated the effect of extreme climate events on wild fruit forest using characteristics of extreme climate indices and tree-ring chronology. We found increasing trends in both extreme precipitation and warm indices, and decreasing trends in cool indices. Extreme climate events were mainly associated with the Atlantic Multidecadal Oscillation (AMO). Analysis of data of wind and geopotential height field at 500 hPa showed that strengthening wind, increasing geopotential height, cyclone and anti-cyclone circulation drivers contributed to extreme climate events. In the non-degraded region, there were significant positive correlations between tree-ring chronology and both extreme precipitation and extreme warm indices (except for warm spell duration indicator). The other extreme indices (except for heavy rain days) had a large correlation range with tree-rings in a 4–8-year period. These results indicated that extreme precipitation and extreme warm indices intensified M. sieversii growth of the non-degraded region on multi-time scales. In contrast, the degraded region showed insignificant negative relationship between tree-ring chronology and both extreme precipitation and extreme warm indices [except for warm spell duration index (WSDI)], and significant negative correlations in a 4–8-year period were detected between tree-ring chronology and most of the extreme precipitation indices, including heavy rain days, very wet days, cold spell duration indicator, simple precipitation intensity index (SDII), and annual total precipitation. Under the long disturbance of inappropriate anthropic activities, extreme climate has caused the outbreak of pests and diseases resulting in the degeneration of wild fruit forest. Our study provides scientific guidance for the ecosystem conservation in wild fruit forest in China, and also across the region.

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Extreme precipitation increases plant biomass through altering nitrogen acquisition by grasses and soil microorganisms

10.5194/egusphere-egu2020-3243 ◽

2020 ◽

Author(s):

Yuqiang Tian

Keyword(s):

Extreme Precipitation ◽

N Uptake ◽

N Recovery ◽

Precipitation Frequency ◽

Extreme Climate Events ◽

Extreme Climate ◽

Extreme Precipitation Events ◽

N Form ◽

Climate Events ◽

N Acquisition

Extreme precipitation events resulting from climate change have strong impact on structure and functions of grassland ecosystems. The extreme climate events may shift plant productivity and nutrient acquisition preferences by roots and microorganisms.We conducted an extreme precipitation simulation experiment and used in-situ 15N labeling of the three N forms to investigate N acquisition (N uptake rate, 15N recovery and preference for N form) by the dominant plant species Stipa grandis and soil microorganisms.Increased rain frequency raised the growth and N acquisition of S. grandis, while microbial N uptake remains unaffected. Microorganisms strongly outcompeted S. grandis for total 15N acquisition, however such superiority decreased in higher extreme precipitation frequency. Plant and microorganisms converged their N demands from distinct to similar preferences for N forms with high precipitation frequency. Such chemical niche partitioning by extreme precipitation effectively reduced root and microbial competition for each N form. Overall, important mechanistical insights into chemical niche differentiation by the effects of extreme climate events and their effects on structure, functions and plant-microbial interactions in temperate grasslands were explained.

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Assessing the Impacts of Extreme Precipitation Change on Vegetation Activity

Agriculture ◽

10.3390/agriculture11060487 ◽

2021 ◽

Vol 11 (6) ◽

pp. 487

Author(s):

Fengsong Pei ◽

Yi Zhou ◽

Yan Xia

Keyword(s):

Return Period ◽

Potential Risk ◽

Extreme Precipitation ◽

Period Analysis ◽

Extreme Climate Events ◽

Extreme Climate ◽

Extreme Precipitation Events ◽

Vegetation Activity ◽

Climate Events ◽

Precipitation Events

Extreme climate events frequently have more severe effects on terrestrial vegetation activity than long-term changes in climate averages. However, changes in extreme climate events as well as their potential risk on vegetation activity are still poorly understood. By using the Middle and Lower Reaches of the Yangtze River (MLR-YR) in China as an example, this paper aims to understand the vegetation response to changes in extreme precipitation events from 1982 to 2012 using the maximum normalized difference vegetation index (NDVI) as an indicator. By applying extreme value theory (EVT), the potential risks of extreme precipitation events on vegetation activity were analyzed by conducting return period analysis. Results indicated that vegetation activity could be affected by extreme precipitation events, especially the combined effects of the frequency and intensity of precipitation extremes. For instance, vegetation activity could be enhanced in the regions with weakened intensity but increased occurrence of extreme precipitation events. In addition, we found potential risk of extreme precipitation events on vegetation activity from the results of precipitation extreme trend and return period analysis. These phenomena can be associated with the local occurrence of extreme precipitation events, different land cover types, and soil moisture cumulative effect on vegetation growth. This study stresses the importance of considering both current changes in and the potential risk of extreme precipitation events to understand their effects on vegetation activity.

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Changes of Extreme Climate Events in Latvia

Scientific Journal of Riga Technical University Environmental and Climate Technologies ◽

10.2478/v10145-012-0010-1 ◽

2012 ◽

Vol 9 (1) ◽

pp. 4-11 ◽

Cited By ~ 5

Author(s):

Zanita Avotniece ◽

Maris Klavins ◽

Valerijs Rodinovs

Keyword(s):

Spatial Heterogeneity ◽

Extreme Precipitation ◽

Negative Temperature ◽

Temperature Extremes ◽

Extreme Climate Events ◽

Extreme Climate ◽

Air Temperatures ◽

Long Term Changes ◽

Climate Events

Abstract Extreme climate events are increasingly recognized as a threat to human health, agriculture, forestry and other sectors. To assess the occurrence and impacts of extreme climate events, we have investigated the changes of indexes characterizing positive and negative temperature extremes and extreme precipitation as well as the spatial heterogeneity of extreme climate events in Latvia. Trend analysis of long-term changes in the frequency of extreme climate events demonstrated a significant increase in the number of days with extremely high air temperatures and extreme precipitation, and a decrease in the number extremely cold days.

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A 414-year tree-ring-based April–July minimum temperature reconstruction and its implications for the extreme climate events, northeast China

Climate of the Past ◽

10.5194/cp-12-1879-2016 ◽

2016 ◽

Vol 12 (9) ◽

pp. 1879-1888 ◽

Cited By ~ 8

Author(s):

Shanna Lyu ◽

Zongshan Li ◽

Yuandong Zhang ◽

Xiaochun Wang

Keyword(s):

Tree Ring ◽

Minimum Temperature ◽

Northeast China ◽

Pinus Koraiensis ◽

Climate Trend ◽

Extreme Climate Events ◽

The Past ◽

Extreme Climate ◽

Climate Events ◽

Standard Tree

Abstract. A ring-width series was used as a proxy to reconstruct the past 414-year record of April–July minimum temperature at Laobai Mountain, northeast China. The chronology was built using standard tree-ring procedures for providing comparable information in this area while preserving low-frequency signals. By analyzing the relationship between the tree-ring chronology of Korean pine (Pinus koraiensis) and meteorological data, we found that the standard chronology was significantly correlated with the April–July minimum temperature (r =  0.757, p < 0.01). Therefore, the April–July minimum temperature since 1600 (more than six trees, but the expressed population signal (EPS) is greater than 0.85 since 1660) was reconstructed by this tree-ring series. The reconstruction equation accounted for 57.3 % of temperature variation, and it was proved reliable by testing with several methods (e.g., sign test, product mean test, reduction of the error, and coefficient of efficiency). Reconstructed April–July minimum temperature on Laobai Mountain showed six major cold periods (1605–1616, 1645–1677, 1684–1691, 1911–1924, 1930–1942, and 1951–1969) and seven major warm periods (1767–1785, 1787–1793, 1795–1807, 1819–1826, 1838–1848, 1856–1873, and 1991–2008) during the past 414 years. The reconstructed low-temperature periods in the 17th and early 18th century were consistent with the Little Ice Age (LIA) in the Northern Hemisphere, and the rate of warming in the 19th century was significantly slower than that in the late 20th century. In addition, the reconstructed series was fairly consistent with the historical and natural disaster records of extreme climate events (e.g., cold damage and frost disaster) in this area. This temperature record provides new evidence of past climate variability, and can be used to predict the climate trend in the future in northeast China.

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A 413-year tree-ring based April-July minimum temperature reconstruction and its implications on the extreme climate events, northeast China

10.5194/cp-2016-38 ◽

2016 ◽

Author(s):

S. Lyu ◽

Z. Li ◽

Y. Zhang ◽

X. Wang

Keyword(s):

Tree Ring ◽

Minimum Temperature ◽

Ice Age ◽

Pinus Koraiensis ◽

Late 20Th Century ◽

Extreme Climate Events ◽

The Past ◽

Extreme Climate ◽

Climate Events ◽

Standard Tree

Abstract. A ring-width series was used as a proxy to reconstruct the past 413-year record of April-July minimum temperature at Laobai Mountain, northeastern China. Chronology was built using standard tree-ring procedures for providing comparable information in this area while preserving low-frequency signals. By analyzing the relationship between the tree-ring chronology of the Korean pine (Pinus koraiensis) and meteorological data, we found that the standard chronology was significantly correlated with the April-July minimum temperature (r = 0.76). Therefore, the April-July minimum temperature since 1600 was reconstructed by this tree-ring series. The reconstruction equation accounted for 57.3 % of temperature variation, and it proved reliable by testing with several methods (e.g., sign test, product mean test, reduction of error, and coefficient error). Reconstructed April-July minimum temperature in Laobai Mountains showed five cool periods (1605–1681, 1684–1690, 1747–1756, 1914–1922, and 1953–1966) and eight warm periods (1697–1704, 1767–1785, 1787–1793, 1795–1801, 1803–1808, 1816–1826, 1835–1878, and 1987–2008) during the past 413 years. The reconstructed low temperature periods in the 17th and early 18th century were consistent with the Little Ice Age in the Northern Hemisphere, and the rate of warming in the 19th century was significantly slower than that in late 20th century. In addition, the reconstructed series was fairly consistent with the historical and natural disaster records of extreme climate events (e.g., cold damage and frost disaster) in this area, and it exhibited 128-60-, 23-22-, 12-10-, 4.0-2.7-, and 2.4-year periods of warm-cool changes, which may be related to variations in sunspot activity or other large-scale interactions between the ocean and the atmosphere.

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