Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati, India.
Glob Chang Biol. 2018 Feb;24(2):e432-e441. doi: 10.1111/gcb.13874. Epub 2017 Sep 14.
Recent studies have shown an increasing trend in hydroclimatic disturbances like droughts, which are anticipated to become more frequent and intense under global warming and climate change. Droughts adversely affect the vegetation growth and crop yield, which enhances the risks to food security for a country like India with over 1.2 billion people to feed. Here, we compared the response of terrestrial net primary productivity (NPP) to hydroclimatic disturbances in India at different scales (i.e., at river basins, land covers, and climate types) to examine the ecosystems' resilience to such adverse conditions. The ecosystem water use efficiency (WUE : NPP/Evapotranspiration) is an effective indicator of ecosystem productivity, linking carbon (C) and water cycles. We found a significant difference (p < .05) in WUE across India at different scales. The ecosystem resilience analysis indicated that most of the river basins were not resilient enough to hydroclimatic disturbances. Drastic reduction in WUE under dry conditions was observed for some basins, which highlighted the cross-biome incapability to withstand such conditions. The ecosystem resilience at land cover and climate type scale did not completely relate to the basin-scale ecosystem resilience, which indicated that ecosystem resilience at basin scale is controlled by some other ecohydrological processes. Our results facilitate the identification of the most sensitive regions in the country for ecosystem management and climate policy making, and highlight the need for taking sufficient adaptation measures to ensure sustainability of ecosystems.
最近的研究表明，干旱等水文气候干扰呈上升趋势，预计在全球变暖与气候变化的背景下，此类干扰将更加频繁和剧烈。干旱会对植被生长和作物产量产生不利影响，从而加剧了印度这样一个拥有超过 12 亿人口的国家的粮食安全风险。在这里，我们比较了印度不同尺度（即河流流域、土地覆盖和气候类型）陆地净初级生产力（NPP）对水文气候干扰的响应，以检验生态系统对这些不利条件的恢复力。生态系统水分利用效率（WUE：NPP/蒸散量）是连接碳（C）和水循环的生态系统生产力的有效指标。我们发现，不同尺度的印度 WUE 存在显著差异（p<0.05）。生态系统恢复力分析表明，大多数流域对水文气候干扰的恢复力不足。一些流域在干旱条件下 WUE 急剧下降，这突出表明了跨生物群落无法承受这种情况。土地覆盖和气候类型尺度的生态系统恢复力与流域尺度的生态系统恢复力不完全相关，这表明流域尺度的生态系统恢复力受到其他一些生态水文学过程的控制。我们的研究结果有助于确定该国对生态系统管理和气候政策制定最敏感的区域，并强调需要采取充分的适应措施以确保生态系统的可持续性。
