Impacts of land use change on carbon storage in the Guangxi Beibu Gulf Economic Zone based on the PLUS-InVEST model

Abstract

Under the vision of the 'dual-carbon' goal, land-use changes and their impact on carbon stocks are studied,to providing a reference for regional carbon balance. Taking the Beibu Gulf Economic Zone of Guangxi as an example, based on the data on land use and carbon density, the PLUS and InVEST models were applied to analyze the pattern of land use change from 1980 to 2020, simulate the spatial pattern of land use under three scenarios in 2030, and assess the carbon stock and its spatial and temporal change characteristics during the 50 years. The results show that: (1) From 1980 to 2020, the land use type of Guangxi Beibu Gulf Economic Zone was dominated by forest land, but the construction land continued to expand, and a large number of other land types were occupied. The formation of a changing trend of "one increase, many decreases" in which construction land increases and other land types decrease. (2) The carbon storage in the Guangxi Beibu Gulf Economic Zone is dominated by forest land, followed by cultivated land. (3) In 2030, there are differences in carbon storage under different development scenarios, and the transformation of land use types related to forest land and construction land dominates the change of carbon storage, and the carbon storage under the natural development scenario and cultivated land protection scenario will decrease to varying degrees, and only the carbon storage will increase under the ecological protection scenario. In 2030, the carbon storage in the ecological protection scenario will be 12.6916 × 108t, an increase of 0.0936 × 108t or 0.7429% compared with 2020. (4) In the past 50 years, the large expansion of construction land in the Guangxi Beibu Gulf Economic Zone has led to a downward trend in carbon storage, and the low-value areas of carbon storage in this area are mainly distributed in the urban areas of various cities and the coastal areas of "Qinbeifang". Hence, the carbon storage has obvious heterogeneity in spatial distribution, showing the characteristics of "low in the middle and high in the periphery".

Keywords: land use; Guangxi Beibu Gulf Economic Zone; InVEST model; PLUS model; carbon storage.

Fig.1

Research framework diagram.

Fig. 2

Location map of Guangxi Beibu Gulf Economic Zone.Note: Maps are based on standard map number GS (2019) 1823. It was downloaded from the website of the China Surveying, Mapping and Geographic Information Standard Map Service of the Map Technology Review Center of the Ministry of Natural Resources of China, and was made by ArcGIS 10.8 without modifying the bottom map boundary. (http:// bzdt. ch. mnr. gov. cn/) The following diagram is made in the same way.

Fig. 3

Drivers of land use change.

Fig. 4

Spatial distribution of land use from 1980 to 2020.

Fig. 5

Spatial distribution of land use by scenario in 2030.

Fig. 6

Statistical chart of carbon stocks from 1980 to 2030.Note: NS natural development scenarios, CS cultivated land protection scenario, ES ecological protection scenarios. The same applies hereinafter.

Fig.7

Spatial distribution of carbon stocks from 1980 to 2030.

Fig. 8

The pattern of carbon storage change from 1980 to 2030.