Hydrological effects of vegetation restoration in karst areas research: Progress and challenges

Abstract

Vegetation restoration is an important way to improve karst ecosystems. Currently, research on the hydrological effects of vegetation restoration in karst areas has made great progress. However, the results obtained from the relevant studies have some limitations and uncertainties. Thus, this paper summarizes the research progress on the effects of karst vegetation restoration on five aspects: soil moisture, evapotranspiration, surface and subsurface runoff, water use efficiency and utilization strategies, and runoff generation and sink processes. The research showed that the existing studies’ evidence of the influence of vegetation restoration on runoff is still contradictory, with some suggesting that vegetation restoration can reduce soil moisture and runoff value, and others saying it can increase it. Furthermore, the ability of different types of vegetation to recover from water deficits varies across time scales, so focusing on spatial and temporal variations in evapotranspiration in karst regions is important. This article investigates water use efficiency in karst areas, as it is mainly controlled by vegetation types, climatic conditions, human activities and geological conditions, meaning the hydrogeological structure of karst has a very fundamental influence on water use efficiency in that region, we also investigate the effects of subsurface conditions in karst areas on the runoff generation and sink process as well as the type and stage of vegetation restoration, and geological factors affect vegetation restoration. Studies on the hydrological effects of vegetation restoration, however, are based on the relationship with a single element, describing its spatial and temporal variability, and they do not sufficiently quantify the reaction principles. This article also analyzes the problems and challenges in current studies, and proposes a combination of geophysical detection, establishing a dynamic model of the co-evolution of karst ecohydrology and surface karst zone mean with fieldwork to further verify the scientific validity of the results.