3. Results
In 2020, the potential GEP for Miyun County was 254.32 billion yuan.
Among all kinds of ecosystem products, the water retention service
contributed the highest (119.5 billion yuan), accounting for 47% of the
potential GEP in Miyun County, followed by natural landscape (52.16
billion yuan). Wetland ecosystems were the main contributors to water
retention services. The value of ecosystem products provided by wetlands
was almost 4.5 times that provided by the other areas (per unit area)
combined.
In 2020, the actual GEP in Miyun County was 53.28 billion yuan. Among
all kinds of ecosystem products, the contribution of climate regulation
service was the highest (17.46 billion yuan), accounting for 32.8% of
the actual GEP in Miyun County, followed by water retention service
(11.86 billion yuan). Forest ecosystems contributed the most to climate
regulation. The value of ecosystem products contributed by wetlands per
unit area was the highest at 96 yuan/m2.
In 2020, among all types of ecosystems in Miyun County, wetlands
contributed the highest potential GEP (141.92 billion yuan), followed by
forests (61.19 billion yuan) and urban ecosystems (0.4 million yuan).
Forests contributed the highest actual GEP (20.49 billion yuan),
followed by wetlands (14.47 billion yuan). The contribution of the urban
ecosystem was the same as its contribution to potential GEP (0.4 billion
yuan). Although the demand in urban ecosystems was theoretically high,
owing to its low supply capacity, the ecosystem products provided by the
urban ecosystem were utilised by residents and contributed to the actual
GEP. The actual GEP accounted for approximately 21% of the potential
GEP, indicating that the overall use intensity of ecosystem products in
Miyun County remained low relative to the service supply capacity. The
difference between the potential and actual GEPs shows the scope for
vast exploitable space for water retention and natural landscape
services in Miyun County and that the local government can further
rationally promote local water resource utilisation and tourism
development.
The spatial distribution patterns of potential GEP in Miyun exhibited
apparent spatial heterogeneity. The potential GEP was high in the
Northwestern region and the surrounding areas of the Miyun Reservoir,
mainly distributed in PLT, SC, HWC, and MCY town. Areas with high values
of ecosystem products were affected mainly by the Miyun Reservoir and
Chaobai River systems, with rich vegetation, high water retention and
climate regulation service values, and relatively complete ecological
functions. Therefore, the supply potential was high. The potential GEP
was low in the Southwest region, mainly distributed in KLC, KYC, and MYT
town, and the low-value area is mainly distributed around the economic
centre of Miyun County. Water and vegetation areas were small because of
the extensive distribution of construction land. Therefore, the supply
potential of ecosystem products was low.
The distribution pattern of the actual GEP in the Miyun area also
exhibited obvious spatial heterogeneity. High actual GEP was primarily
associated with the southwest region, such as KLC, KYC, and MYT town,
with rapid economic and social development, high levels of regional
economic development, dense populations, and high intensities of
ecosystem product use. Areas with low actual GEP, such as HCT and PC
towns, were mainly distributed in the Northeast. Owing to their low
degree of development and utilisation, poor regional accessibility, and
low population, the intensity of the use of ecosystem products was low.
The difference between the potential and actual GEPs in Miyun tended to
be lower in the Southern region and higher in the Central and Northern
regions, indicating some imbalance. From the perspective of spatial
distribution, GEP surplus areas were mainly distributed in PLT and SC
towns and other Northwestern regions. In the Southwest regions,
including KLC, KYC, TY, and MYT towns, the regional economic development
speed is fast, the construction land area is large, and the ecological
resource utilisation intensity is high. Consequently, the potential
supply of ecosystem products could not meet the needs of residents, as
reflected in the GEP deficit. In addition, there is a trend of spatial
expansion from the economic centre in the Southwest to the surrounding
SLP, HNC, HTK towns, and other regions. The GEP surplus was high in the
Northwestern region, with an excellent ecological environment and
relatively low population density. The areas centred around the Miyun
Reservoir, such as HWC, MCY, and TCT town, are close to the reservoir,
rich in water resources and fishery products, and have strong climate
regulation ability, which brings high tourism and cultural value. As a
result, the potential GEP of the reservoir around the bank and the
supply potential were high, differing substantially from the
high-deficit areas outside the bank.
For natural ecosystems (forests, shrubs, grasslands, and wetlands), the
potential GEP was positively correlated with the actual GEP
(R2 = 0.61). It follows that, within the scope of
natural ecosystems in a region, the greater the supply intensity of
ecosystem products, the higher the use intensity. However, due to human
interference’s intensity, farmlands, towns, and bare lands did not show
apparent correlations. Correlation analysis of the driving factors with
potential and actual GEP showed that the natural ecosystem area
(R2 = 0.88) and vegetation coverage
(R2 = 0.73) were the main driving factors affecting
potential GEP in Miyun County. The GDP (R2 = 0.84) and
population (R2 = 0.82) were the main driving factors
affecting GEP in Miyun County.