# Drought: A Common Environmental Disaster
## 6 Ecosystem Services and Drought  
Drought has a variety of effects on the environment. Plants and animals, like humans, rely on water. When there is a drought, their food source may be reduced, and their habitat may be harmed. Reduced food and water supplies have resulted in an increase in sickness in wild animals [108]. Ecosystem services play a critical role in environmental management and policy development. The Millennium Ecosystem Assessment [109] defines ecosystem services as the benefits humans derive from ecosystems and includes providing, regulating, cultural and supporting services [110]. The availability of freshwater is critical to human well being and a healthy economy. Freshwater supply is a vital provisioning service that describes the ecological alteration of water utilised for a variety of uses, including drinking, irrigation, hydropower production, recreation and fisheries [111]. In addition to freshwater, food supply is another important provisioning service and is tightly linked with freshwater provisioning [110]. Drought occurrences become more intense and frequent as a result of climate change and variability, with severe effects on freshwater and food availability. During droughs, the water deficit propagates through the hydrological cycle, diminishing stream flow, lake levels and groundwater levels, and is sometimes referred to as hydrological drought. During drought periods, stream water quality may degrade due to prolonged low-flow conditions and high water temperatures [110; 112; 113]. Droughs that affect water availability and quality can have a significant impact on freshwater supplies. Drought, in addition to freshwater, may reduce plant growth and crop productivity due to precipitation and soil moisture shortages, potentially affecting food-provisioning services [114; 115]. The relevance of freshwater and food supply in ensuring food security and economic growth necessitates an assessment of the effects of drought on these ecosystem services. The number of studies on the idea and valuation of ecosystem services has risen dramatically in recent years. The relevance of considering ecosystem services when making land-use and management decisions is now widely acknowledged [110; 111]. Studies on quantitative estimates of ecological services, on the other hand, are still scarce [111; 116]. Even fewer studies have been carried out to quantify ecosystem services in response to extreme climate events, such as drought [117; 118]. Using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST)--an ecosystem service tool--[PERSON] et al. [119] assessed changes in the supply of freshwater provision and erosion control services in a Mediterranean river basin during exceptional dry and rainy years. Under future scenarios with a higher frequency of floods and droughts, the scientists reported that drinking water provisioning services decreased by 3 to 49 percent, while erosion management decreased by 5 to 43 percent. When compared to typical years, drinking water and electricity output were about 100 percent lower, while water purification services gave greater benefits in dry years [119]. In the last two decades, there has been a significant increase in the number of studies on the effects of drought on hydrology and water quality [120; 121]. Summer thoughts had a negative influence on water quality in the Meuse River, according to [PERSON] and [PERSON] [122]. Droughts had a negative impact on water quality in terms of water temperature, eutrophication, and some heavy metals and metalloids, while droughts had a favorable impact on nitrate. Similarly, multiple studies on the effects of drought on crop production have recently been published [10; 123]. For example, [PERSON] et al. [85] calculated the effects of climate variability on crop productivity and found that drought stress lowered the total yield by 8.1 to 17.5 percent at their four study locations in the Midwest United States.