3.2. Evaluation of regulation services
After a city enters the stable development stage, heat island effect,
environmental pollution, too high urban population density, and poor
social health, threatened safety and other social problems have
gradually emerged. Due to the destroyed urban natural environment, the
influences of the natural environment on human survival, life, and
production are widely concerned. Therefore, the benefits of urban water
bodies and green spaces have been extensively explored in order to
arouse public awareness of nature protection. Subsequently, relevant
evaluation index systems were established to evaluate the environmental
loss and develop a reasonable and targeted restoration plan based on the
key impact indices. Therefore, the targets of evaluation index systems
were gradually changed from ecosystem supply services to regulation
services (Table 3).
The regulation services of an urban ecosystem involve four aspects:
hydrology, ecology, environment, and society. The evaluation indices of
the regulation services of urban rivers and lakes involve the elements
of six aspects: hydrological characteristics, water environment quality,
structure and function of water ecosystems, waterfront spatial
structure, landscape effect, and stress factors (Zhang et al. ,
2005). The indices that fully reflect the pressure, state, and response
of river basins, such as population density, annual GDP growth rate,
water resources per capita, annual rainfall, forest coverage, and
industrial wastewater treatment rate, should be selected to evaluate the
health status of ecosystems (Yan et al. , 2008). In addition, the
wind environment, light environment, building and surrounding
environment can be selected to comprehensively evaluate the greening
development potential and quantitatively analyze the cooling
characteristics and cooling efficiency of vertical greening (Shi, 2018).
In Wetland Ecosystem Health Evaluation Index System proposed by the
Wetland Conservation and Management Center of the State Forestry
Administration, the health status of wetland ecosystems should be
evaluated in five aspects: water environment, soil, biology, landscape,
and society (Qian et al. , 2016).
These evaluation systems comprehensively consider the ecological service
functions of water bodies and green spaces in urban ecosystems for
regulating climate and preventing floods, and can analyze the factors
affecting the stability of urban ecosystems based on specific functional
indices and evaluation results. The comprehensive evaluation based on
water, soil, land, atmosphere reflects the interaction between various
natural elements, so that the environmental problems can be explored and
the health conditions of ecosystems can be judged by evaluation results
for ecosystem restoration. Due to the enhanced awareness of ecological
civilization and natural restoration in urban planning, the
comprehensive evaluation of water bodies and green spaces is
significant. In the comprehensive evaluation, some characteristic
indices are integrated together to reflect the interaction between them
and the characteristics of the urban blue-green space as a composite
ecosystem and improve the evaluation system.