Drought trigger thresholds for different levels of vegetation loss in China and their dynamics

Guo, Wenwen; Huang, Shengzhi; Huang, Qiang; Leng, Guoyong; Mu, Zhenxia; Han, Zhenyu; Wei, Xuesong; She, Dunxian; Wang, Hanye; Wang, Zhixia; Peng, Jian

doi:10.1016/j.agrformet.2023.109349

Cited by 34 publications

(5 citation statements)

References 80 publications

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“…Although we attempt to reveal the spatiotemporal pattern and dominant factors of flash drought recovery, it is important to acknowledge some limitations. Various drought trigger thresholds may lead to varying degrees of vegetation productivity loss (Guo et al 2023). If the threshold of vegetation tolerance is exceeded, the impact becomes irreversible, potentially preventing the recovery of vegetation from droughts (Sun et al 2023).…”

Section: Discussionmentioning

confidence: 99%

Heterogeneity in vegetation recovery rates post-flash droughts across different ecosystems

Lu,

Sun,

Cheng

et al. 2024

Environ. Res. Lett.

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Flash droughts, as sub-seasonal phenomenon, are characterized by their rapid onset and significant impact on terrestrial ecosystems. However, understanding how vegetation responds to flash droughts and mechanisms governing vegetation recovery remains elusive. Here, we analyzed the response of vegetation productivity to flash droughts and the most relevant drivers in post-flash drought vegetation recovery during the growing season using two soil moisture datasets (ERA5-land and GLDAS) and two satellite-based vegetation productivity proxies (Gross Primary Productivity, GPP and Solar-induced chlorophyll fluorescence, SIF). Our results show that South China and Northeastern China stand out as hotspots for flash droughts, with higher frequency and speed. Notably, although the frequency of flash droughts in cropland is relatively low, its speed is very high, with a median of 10.9% per pentad. Most ecosystems can recover to their normal state within 25 days. Vegetation with shallow roots, such as cropland and grassland, responds rapidly to flash droughts. Ecosystems generally exhibit extended response time with increasing plant rooting depth. The recovery rate of vegetation productivity from flash droughts is mainly controlled by vegetation physiology (decline rate of productivity upon exposure to flash drought) and modulated by flash drought characteristics, especially severity for forests and speed for cropland and grassland. This study provided valuable insights into the mechanisms underlying vegetation responses to flash droughts.

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Section: Discussionmentioning

confidence: 99%

Heterogeneity in vegetation recovery rates post-flash droughts across different ecosystems

Lu,

Sun,

Cheng

et al. 2024

Environ. Res. Lett.

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“…However, stressors other than climate extremes could also be studied using our approach, provided the stressor affects vegetation NDVI (e.g., seasonal insect outbreaks). Examples of other possible study systems include savanna grass specialists of El-Niño affected South Africa [82], or environments in China where vegetation loss in drought is substantial 13 [83]. Such systems could feature generalist herbivores because the NDVI is responsive to productivity in most plants [34,84]; however, analyses may be more complicated if diets are diverse.…”

Section: Further Applications In Other Systems and In Managementmentioning

confidence: 99%

Identifying Habitat Productivity Thresholds to Assess the Effects of Drought on a Specialist Folivore

Kotzur,

Moore,

Meakin

et al. 2024

Preprint

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Climate change has altered the frequency and severity of extreme weather, which can affect vegetation condition and habitat quality for wildlife. Declines in vegetation productivity during droughts and heatwaves can negatively impact animals that depend on vegetation for water and nutrition. The ability to detect such effects on habitat suitability can reveal refugia, which can be prioritised for protection to improve threatened species conservation. We used the normalised difference vegetation index (NDVI) to look at relationships between vegetation productivity and the presence of koalas (Phascolarctos cinereus) in potential habitat throughout much of their range. Using a large, long-term koala presence dataset, we tested the hypothesis that locations where koalas had been observed would exhibit higher NDVI values than a random, representative sample from the same vegetation group (i.e. woodlands, open forests or tall open forests). We also identified the minimum NDVI threshold at which koalas occurred across time for each vegetation group and compared these to the minimum NDVI values observed across potential koala habitat before and during the millennium drought; one of the worst recorded in Australia. Additionally, we investigated whether vegetation above the minimum NDVI thresholds was significantly closer to perennial water than unsuitable vegetation. We found that koalas tend to occur at locations exhibiting higher NDVI than average for all vegetation groups. We also found that 49% of all vegetation groups maintained a minimum NDVI above the koalas’ NDVI threshold before drought, equating to 190,227 km2, which declined to 166,746 km2 during drought (a 12% reduction). We also found that unsuitable vegetation tended to occur farther from perennial water than suitable vegetation for some vegetation groups. Areas that remained above the NDVI thresholds during the drought should be considered potential refugia for populations during an event of similar magnitude and could indicate future core habitat extent.

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“…In general, drought can be divided into four types: meteorological drought, hydrological drought, agricultural drought, and socio-economic drought (Van Loon 2015. Meteorological drought is usually the primary driver of other types of droughts, and it is also the basis for forecasting other types of droughts (Mishra et al 2010, Liu et al 2016a, Han et al 2021, Bas ¸agaoglu et al 2023, Guo et al 2023. Therefore, it is essential to evaluate the relationships between meteorological drought and other types of droughts.…”

Section: Introductionmentioning

confidence: 99%

A new perspective for assessing hydro-meteorological drought relationships at large scale based on causality analysis

Zhou,

Ding,

Zhao

et al. 2023

Environ. Res. Lett.

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Correlation analysis is the common method to evaluate the relationship between two variables; however, it may sometimes cause spurious correlations. Specifically, in the field of hydrometeorology, with the impacts of climate change and human activities, correlation analysis is difficult to identify the true relationship between variables, and thus, causality analysis should be adopted instead. This study analyzed the causal relationship between meteorological drought and hydrological drought in different climatic regions of China by using convergent cross mapping (CCM). We improved the identification of CCM convergence by using the coefficient of variation and applied it in the field of large-scale hydrometeorology. The results of correlation analysis were compared, and the applicability of causality analysis was explored. The results revealed that: In Southeast China, the correlation and causality between meteorological drought and hydrological drought were both large. In Northeast China and central Qinghai–Tibet Plateau, the correlation between meteorological drought and hydrological drought was small, but the causality was large. In view of the spurious correlation, introducing causality analysis can better explain the relationship between meteorological drought and hydrological drought, especially in areas with snowmelt runoff. Overall, CCM can provide valuable causal information from common time series in the field of large-scale hydrometeorology and has a wide range of application values. However, causality analysis cannot explain the positive or negative relationship between variables. Therefore, when analyzing the relationship between variables, the advantages of the two methods should be given full play.

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Drought trigger thresholds for different levels of vegetation loss in China and their dynamics

Cited by 34 publications

References 80 publications

Heterogeneity in vegetation recovery rates post-flash droughts across different ecosystems

Heterogeneity in vegetation recovery rates post-flash droughts across different ecosystems

Identifying Habitat Productivity Thresholds to Assess the Effects of Drought on a Specialist Folivore

A new perspective for assessing hydro-meteorological drought relationships at large scale based on causality analysis

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