The Impact of Land Use and Land Cover Changes on Ecosystem Services Value in Laos between 2000 and 2020

Abstract

Land use and land cover changes significantly affect the function and value of ecosystem services (ES). Exploring the spatial correspondence between changes in land cover and ES is conducive to optimizing the land use structure and increasing regional coordinated development. Thus, this study aimed to examine changes in land use and land cover (30 × 30 m) in Laos between 2000 and 2020 and their effects on ecosystem services value (ESV) using the Global Surface Cover Database land use data for 2000 to 2020, ArcGIS technology, and the table of Costanza’s value coefficients. The study results indicated that forest (79.5%), cultivated land (10.6%), and grassland (8.3%) were the dominant land use types in Laos over the past two decades. The forest area decreased significantly, while there were increases in other land types, and the forest was transformed into cultivated land and grassland. ES in Laos was valued at about USD 140–150 billion, with forest contributing the most, followed by cultivated land and grassland. ESV over the last two decades in Laos has increased by USD 3.94 million. Large values were assigned to regulating services (40%) and supporting services (14%). The ESV of food production, soil formation, and water supply increased, and the ESV of climate regulation, genetic resources, and erosion control decreased. In addition, the elasticity value of artificial surfaces was more prominent, with a more evident impact on ESV. For future development, Laos should rationally plan land resources, develop sustainable industries, maintain the dynamic balance of second-category ESV, and achieve sustainable economic and ecological development. This study provides a scientific basis for revealing changes in ESV in Laos over the past two decades, maintaining the stability and sustainable development of the environment in Laos, and realizing the sustainable use and efficient management of the local environmental resources.

1. Introduction

Ecosystem services refer to the benefits natural ecosystems provide, directly or indirectly, to people [1]. Since there are different terrestrial ecosystems, changes in land use and land cover (LULC) directly influence ecosystem structure and functioning [2,3,4] and are crucial for maintaining ecosystem functions [5,6,7]. Recently, as attention to changes in LULC and ES has grown, research hotspots have emerged in measuring potential ES and ecological benefits, assessing the effect of changes in LULC on the ESV, and quantitative ESV [8,9,10]. Daily [11] proposed improvements to the study of ES and its value. Then Costanza et al. [12] valued global ES for the first time, concluding that the annual service value of global terrestrial ecosystems was about USD 12 trillion, mainly in wetland and forest services, which accounted for 40% and 38%, respectively. Moreover, Brown [13] investigated the relationship between global changes in LULC and the socioeconomic ESV. Additionally, Lautenbach et al. [14] split the ES functions into four groups and conducted an expert-based examination of ESV in Germany. According to Dawson et al. [15], the effect of societal complexity on ESV must be considered to ascertain if the research on ESV can act as a rational basis for the management and allocation of the environment. Furthermore, Hassan et al. [16] proposed that ecosystems in various locations exhibit spatial heterogeneity. Consequently, the same ESV coefficients cannot be applied to evaluations of various study regions. The ecosystem service-equivalent value approach was utilized by Wang et al. [17], Srikanta et al. [18], and Jiang et al. [19] for determining the ecological service value for various LULC categories. However, these studies failed to consider ESV heterogeneity due to the uneven LULC distribution in the various locations and the inherent connection between ESV and changes in LULC. This made it impossible to distinguish between the subtle variations in ESV due to various LULC types. Laos is a global biodiversity hotspot with high biodiversity and conservation value [20]. However, as the poorest and least developed small, landlocked country in Southeast Asia [21], the economic development and population growth in recent years, have caused Laos to face many environmental and ecological challenges, such as severe land degradation, biodiversity loss, and reduced forest coverage. Significant changes have been made to the local LULC structure. The environment is sensitive, and the ecological damage has worsened in some regions [22]. Maintaining regional security of the ecosystem and sustainable socioeconomic growth is strongly tied to the changes in the Laotian ecology and its services. Thus, unreasonable LULC changes may lead to potential ecological and environmental risks. There have been limited studies on the ESV and LULC changes in Laos. Past studies on changes in LULC have mainly focused on specific areas (a single province) or a particular land type [23,24,25], and the evaluation of the ESV has mainly been concentrated on a specific type of ecosystem [26,27,28]. These research methods are singular, and the research foundation needs to be stronger, making it challenging to meet local development conditions. Since ESV has apparent scale effects, macro-level analysis of the study area cannot fully reflect the impact of local and regional land use changes on ESV [29].

The Millennium Ecosystem Assessment initiated by the United Nations classifies the ecosystem services value (ESV) into four first categories [1]: (1) provisioning services; (2) supporting services; (3) regulating services; and (4) cultural services [30]. Costanza et al. divided ecosystem services into 17 second categories based on the 4 first categories, including only renewable services but excluding non-renewable fuels and minerals [31]. Based on the ESV model and ecosystem value coefficient, and concerning the equivalent factor method based on unit area value proposed by Xie et al. [32], and combined with the actual land use situation in Laos, we locally corrected the equivalent of various ecosystem service functions. An ESV equivalent table suitable for Laos was constructed and optimized for usability, interpretability, and suitability. Compared with the standard conditional value method [17], shadow engineering method [33], market opportunity method, and asset value method [34], our research method has the advantages of ease of use, lower data requirements, high comparability of results, and comprehensive evaluation. This study is the first to use the entire country of Laos and its 17 provinces and one particular region as the study area to analyze the impact of land use changes on the ESV from a global and local perspective. This study fills in the Laos land in the impact of utilization changes on ESV, which can provide a reference for optimal LULC allocation, ecological security management, and control decisions in Laos.

2. Study Area and Data Resources

2.1. Description of the Study Area

Laos is the only landlocked country in Southeast Asia, and it is located between 13°56–22°27′ N and 100°02–107°38′ E (Figure 1). Laos is bordered by Myanmar, Thailand, Cambodia, Vietnam, and Yunnan Province, China in the northwest, southwest, south, east, and north. It has a land area of about 23.01 × 10⁴ km², which is dominated by forest (about 53.3% of the land area) and shrubland (about 32.4% of the land area). Laos represents a critical area of high species biodiversity globally, and it is rich in animal and plant species [20]. One-fifth of the land area of Laos is plains, and four-fifths are mountains and plateaus. The landscape is typically flat, high, and low in the west, east, and south. Additionally, the country has long northern and southern borders and narrow eastern and western borders. The Mekong River flows through Laos and is among the country’s many abundant water resources. Most of the Mekong River’s Laos segment is through mountains and plains, with productive land along the alluvial plain. Laos is also a significant agricultural region and falls into a tropical and humid subtropical climate zone with high temperatures. The dry season occurs between November and April of the following year, whereas the rainy season occurs between May and October. The mean yearly temperature is 20 to 30 °C, and the typical yearly rainfall is between 1250 and 3750 mm. Due to the acceleration of human activity and the effects of climate change, Laos has experienced recent rapid changes in LULC, which has likely affected the ESV. Therefore, exploring the relationship between the two is essential for land planning and ecological protection.

2.2. Data Sources

Two LULC datasets for 2000 to 2020 were provided by the GlobeLand30 Global Surface Cover Database, https://www.un-spider.org/ (4 June 2023) at a resolution of 30 × 30 m. These data have ten first categories: forest, shrubland, wetland, grassland, cultivated land, tundra, bare land, artificial surface, water bodies, perennial snow, and ice. This dataset has a long time span and high accuracy, which met the research needs. The other data source was the table of Costanza’s value coefficients [12]. According to the actual LULC in Laos, the present study combined the ten LULC categories into eight categories: artificial surfaces, bare land, cultivated land, forest, grassland, shrubland, water, and wetland. The vector data on Laos’s primary geographic and administrative divisions were derived from the Food and Agriculture Organization, https://data.apps.fao.org/ (4 June 2023).

3. Methods

3.1. Analysis of the Transitions in Land Use and Land Cover

3.1.1. Calculation of the Land Use and Land Cover Transfer Matrix

The Markov model lists the area of LULC transfer changes in matrix form to determine the spatiotemporal evolution of the LULC pattern [35]. The matrix of LULC transfer is primarily used to statistically investigate the degree and trends in mutual LULC transformation across different types of LULC to accurately depict the structural properties of LULC change and the relationship between different types of LULC [35,36]. Therefore, this study used this method to define the vectors in the LULC transfer matrix as land use type areas and to analyze the change in area occupied by each LULC type in Laos between 2000 and 2020 to other types of LULC (transferred out) and the change in area occupied by other LULC types to that LULC type (transferred in) from both quantitative and spatial aspects.

$$S_{ij}=\left[\begin{array}{ccccc}{S}_{11}& S_{12}& S_{13}& \cdots & S_{1n}\\ S_{21}& S_{22}& S_{23}& \cdots & S_{2n}\\ \cdots & \cdots & \cdots & \cdots & \cdots \\ S_{n1}& S_{n2}& S_{n3}& \cdots & S_{nn}\end{array}\right]$$

(1)

where, $S$ represents area, $n$ represents the quantity of LULC types ($n$ = 8), and $i$ and $j$ are types of LULC at the start of the study (2000) and termination of the study (2020), respectively.

3.1.2. Hot Spot Analysis of the Land Use and Land Cover Change Map

The Hot Spot Analysis can identify statistically significant hot and cold spots using the local General G index statistic [37]. A feature that has high value and is surrounded by features with high values is a hot spot. In contrast, a feature that has low values and is surrounded by features with low values is a cold spot [38]. The Reclass by Table tool was used in ArcGIS 10.2 software (ESRI, Redlands, CA, USA) to extract the maps of 2000 and 2020, and the Raster calculator was used to identify the spatial change in area for each class from 2000 to 2020. Then the Fishnet tool was used to generate a 30 × 30 km vector grid of the study area as the basic unit for the analysis of the hotspot change in each class. Subsequently, the Zonal statistics tool was applied to calculate the changing area of each class in each grid unit to obtain a hotspot map of changes in LULC in the study area during this period and highlight and identify the significant areas of LULC change in Laos.

3.2. Estimation of Ecosystem Service Value

The present study combined the method of Xie et al. [32] with actual LULC in Laos to localize the equivalent of each ESV function to obtain the coefficient table of ESV for Laos (

Table 1. The coefficient table of the ESV in Laos (USD km⁻² a⁻¹).

First Category	Second Category	Artificial Surfaces	Bare Land	Cultivated Land	Forest	Grass Land	Shrub Land	Water Bodies	Wetland
Provisioning services	Food Production	0.00	0.00	23.23	2.00	11.92	6.96	1.06	6.14
	Raw Materials	0.00	0.00	2.19	0.84	0.54	0.69	0.00	5.39
Regulating services	Gas Regulation	0.00	0.00	0.00	0.12	0.09	0.11	0.00	0.00
	Climate Regulation	9.05	0.00	4.11	20.44	0.40	10.42	0.00	4.88
	Disturbance Regulation	0.00	0.00	0.00	0.66	0	0.33	0.00	29.86
	Water Regulation	0.16	0.00	0.00	0.08	0.03	0.06	75.14	56.06
Supporting services	Water Supply	0.00	0.00	4.00	0.27	0.60	0.44	18.08	4.08
	Erosion Control	0.00	0.00	1.07	3.37	0.44	1.91	0.00	26.07
	Soil Formation	0.00	0.00	5.32	0.14	0.02	0.08	0.00	0.00
	Nutrient Cycling	0.00	0.00	0.00	0.03	0.00	0.02	0.00	17.13
	Waste Treatment	0.00	0.00	3.97	1.20	0.75	0.98	9.18	30.15
	Pollination	0.00	0.00	0.22	0.30	0.35	0.33	0.00	0.00
	Biological Control	0.00	0.00	0.33	0.11	0.31	0.21	0.00	9.48
	Habitat/Refugia	0.00	0.00	0.00	0.39	12.14	6.27	0.00	24.55
	Genetic Resources	0.00	0.00	10.42	15.17	12.14	13.66	0.00	0.99
Cultural services	Recreation	57.40	0.00	0.82	8.67	0.26	4.47	21.66	22.11
	Cultural	0.00	0.00	0.00	0.02	1.67	0.85	0.00	19.92

Note: (1) The equivalent factor coefficient of building land was adopted as the ESV indicator of artificial surfaces; (2) The equivalent factor coefficient of bare land was adopted as the ESV indicator of bare land; (3) The ratio of paddy fields to dry land in Laos is ~ 8:2, and the weighting of the equivalent factor coefficient of paddy field and dry land was adopted as the ESV indicator of cultivated land; (4) The dominant category of forest in Laos is deciduous mixed forest, and the equivalent factor coefficient for this forest category was adopted as the ESV index of forest; (5) The equivalent factor coefficient of grassland was adopted as the ESV indicator of grassland; (6) The equivalent factor coefficient of shrub forests was adopted as the ESV indicator of shrubland; (7) The equivalent factor coefficient of water bodies was adopted as the ESV indicator of water bodies; (8) The equivalent factor coefficient of wetlands was adopted as the ESV indicator of wetland; (9) Since the terrain, topography, and climate conditions of Laos are relatively similar to those of Yunnan Province, China, they were uniformly corrected based on the equivalent factor correction coefficient (0.64) for this province [32].

). According to the average grain output (kg/km²) and average grain price (USD/kg) of Laos in 2000 and 2020, we corrected and calculated the equivalent factor of Laos (USD/kg). The value coefficient of the ESV equivalent factor is 1/7 of the market value of 0.01 km² cultivated land grain yield in the region, calculated as:

$$V_{\mathrm{C}0}={\displaystyle \frac{1}{7}}\times P\times {\displaystyle \frac{1}{n}}{\displaystyle \sum }_{i=1}^n{Q}_i$$

(2)

where $V_{\mathrm{C}0}$ is the value coefficient of the ESV equivalent factor (USD km⁻² a⁻¹), $P$ is the national average grain price (USD kg⁻¹), $Q_i$ is the average grain yield in the study area (kg km⁻²), and $n$ is the number of years.

The ESV was calculated as:

$${\mathrm{ESV}}_t={\displaystyle \sum _{k=1}^n\left(A_{kt}\times V{C}_k\right)}$$

(3)

where ${\mathrm{E}\mathrm{S}\mathrm{V}}_t$ is the total ESV in Laos in year $t$ (2000 or 2020), $A_{kt}$ represents the area occupied by the kth type of LULC in Laos in year $t$ (2000 or 2020), $V{C}_k$ denotes the ESV coefficient of the kth type of LULC, and $n$ is the number of LULC types ($n$ = 8).

$${\mathrm{ESV}}_{cr}={\displaystyle \frac{{\mathrm{ESV}}_{t2}-{\mathrm{ESV}}_{t1}}{{\mathrm{ESV}}_{t1}}}\times 100\%$$

(4)

where ${\mathrm{E}\mathrm{S}\mathrm{V}}_{cr}$ is the rate of change in ES values of Laos, and ${\mathrm{E}\mathrm{S}\mathrm{V}}_{t1}$ and ${\mathrm{E}\mathrm{S}\mathrm{V}}_{t2}$ are total ESV of Laos at $t1$ (2000) and $t2$ (2020).

$${\mathrm{ESV}}_{ft}={\displaystyle \sum _{k=1}^n\left(A_{kt}\times V{C}_{fk}\right)}$$

(5)

where ${\mathrm{E}\mathrm{S}\mathrm{V}}_{ft}$ is the $f$th second-category ESV ($f$ = 1, 2, 3, …, 17) in Laos in year $t$ (2000 or 2020), and $V{C}_{fk}$ is the coefficient of the $f$th second-category ESV corresponding to the $k$^th LULC type in Laos.

The natural breaks (Jenks) approach was then used to separate the spatial distribution of ESV in Laos between 2000 and 2020 into five categories: (1) very low; (2) moderately low; (3) medium; (4) high; and (5) very high.

3.3. Deteriorated Contribution Rate of Ecosystem Service Value

This indicator refers to the proportion of changes in ESV of various LULC types in the total changes in ESV and can be used to judge the impact of changes in various LULC types on changes in ESV. The formula is shown below:

$$ES{V}_c={\displaystyle \frac{ES{V}_{ib}-ES{V}_{ia}}{ES{V}_b-ES{V}_a}}\times 100\%$$

(6)

where $ES{V}_c$ is the contribution rate of ecosystem service value variation; $ES{V}_{ia}$ and $ES{V}_{ib}$ are the ecosystem service values of the i-th land use and land cover type at the initial and final stages of the study, respectively; and $ES{V}_a$ and $ES{V}_b$ are the ecosystem service values at the initial and final stages of the study, respectively.

According to the general situation, the following explanation is made: If $ES{V}_c$ < 0, it means that the ESV of the i-th LULC type at the beginning and end of the study has an opposite trend to the regional ESV. If the regional ESV gradually decreases, then the i-th LULC type is considered to make a positive contribution to the ESV. If the regional ESV shows an increasing trend, the i-th LULC type is considered to have a negative contribution to the ESV. If $ES{V}_c$ > 0, it means that the changes of the i-th LULC type during the study period are consistent with the changes in regional ESV; if the ESV increases, the i-th LULC type makes a positive contribution to the ESV. If the regional ecosystem service value decreases, the i-th LULC type makes a negative contribution to the ESV.

4. Results

4.1. Land Use and Land Cover Changes in Laos

4.1.1. Trends in Transfer of Land Use and Land Cover

Figure 2 and Figure 3 map the distribution and areas of LULC types in Laos in 2000 and 2020, respectively. The development of the topography, river systems, and the area used for human social and economic activities was in line with the distribution of the LULC categories. Natural and ecological resources were abundant in Laos, and 85.7% of the area was covered by natural vegetation, including woodlands and shrubland. About 53–54% of Laos’s geographical area was covered by forest, primarily in the high-altitude regions. While evergreen broad-leaved forests are typically found in the central regions and regions at high altitudes, deciduous broad-leaved forests dominate low- and mid-altitude plains and hills. Shrubland (about 32.4%) was mainly found in the mid-altitude areas of Laos, and cultivated land (about 12.7%) was Laos’s third most extensive LULC type, mainly rainfed with a few irrigated farmlands. Most rainfed cropland of Laos is in the plains of the Mekong River Catchment south of Vientiane and near numerous small basins running along the Mekong River and its tributaries to the north of Vientiane. The distribution range of the construction land was small, except for in the capital, Vientiane, where the area was small and scattered. Despite its small size, most of the grassland was located in the plateau region.

In Laos, there was no appreciable change in the overall area or distribution of the different LULC types between the two periods. The changed area only accounted for 3.23% and 4.98% of Laos’ land area. Except for the glaciers, some transferred out of and transferred into the various categories of LULC (

Table 2. The conversion matrix of LUCC in Laos from 2000 to 2020 (km²).

	2020
2000	Artificial Surfaces	Bare Land	Cultivated Land	Forest	Grassland	Shrubland	Water Bodies	Wetland	Total (2000)	Transfer Out 2000
Artificial Surfaces	112.39	0.00	17.34	2.53	0.98	0.01	0.53		133.77	21.38
Bare Land	0.03	79.50	2.41	31.25	18.22		0.83	0.00	132.23	132.20
Cultivated land	426.68	1.38	20,738.63	1329.15	354.16	5.23	90.26	33.32	22,978.80	22,552.12
Forest	206.07	39.89	6033.40	203,587.45	6734.18	101.25	449.41	37.27	217,188.93	216,982.86
Grassland	80.08	23.77	1153.69	5310.04	14,604.59	102.37	124.50	5.51	21,404.54	21,324.46
Shrubland	0.47		9.23	91.47	64.84	201.58	2.24		369.83	369.36
Water bodies	4.00	7.69	89.18	249.22	76.23	3.69	2058.04	19.03	2507.09	2503.09
Wetland	0.35		14.83	10.99	16.58	0.01	12.99	106.70	162.45	162.10
Total (2020)	830.07	152.23	28,058.69	210,612.10	21,869.77	414.15	2738.80	201.82	264,877.63
Transfer in 2020	717.68	152.23	28,041.35	210,609.57	21,868.79	414.14	2738.27	201.82
Area change 2000–2020	696.30	20.00	5079.89	−6576.83	465.23	44.32	231.71	39.38

). Specifically, the forest area decreased, while the area of artificial surfaces, cultivated land, shrubland, bare land, grassland, water, and wetland increased. Among them, the area of forest transferred in was the largest, and it had the most significant reduction area (−6576.83 km²), with an overall declining trend. The cultivated land area transferred in and transferred out was the second largest, with the largest increase (2079.89 km²). The increase followed this in the area of artificial surfaces of 696.3 km², which was Laos’s most dramatic change in the type of LULC.

The main manifestations of the transfer of LULC in Laos at this time included the transformation of the natural landscape into an artificial landscape, the one-directional transfer of the forest to shrubland and cultivated land, the internal transfer of the natural or artificial landscape, and the reversal of the artificial landscape into the natural landscape. For instance, the area of forest decreased significantly, and 3.1% of the area of forest changed to grassland. Additionally, the cultivated land increased the most, and the cultivated land transferred mainly came from forests (21.52%), grassland (4.11%), water, and artificial surfaces. However, 5.89%, 1.89%, and 1.57% of the cultivated land area were converted to forest, artificial surfaces, and grassland, respectively. The transferred artificial surfaces were mainly derived from cultivated land (59.45%) and forest (28.71%).

4.1.2. Hotspots of Land Use and Land Cover Changes in Laos

Figure 4 shows the spatial distribution of the intensity of changes in LULC of the eight land types in Laos during this period. Among them, the forest area in northern Laos showed an upward trend, especially in the Phongsali (PH) and Louang Namtha (LM) provinces. A few provinces (such as the northern part of Houaphan [HO] and southern Attapu [AT]) had an increase, and in other provinces, the changes were not noticeable. In the northern and central provinces (such as HO, Xaignabouri [XA], Vientiane [VT], and Bolikhamxai [BL]), the grassland area showed a decline, while in the southern plains and hilly areas, there was a slight increase in the trend. Most provinces’ cultivated land areas tended upward, especially in the northern and central areas. Some provinces (such as PH, HO, Xiangkhoang [XI], Louangphrabang [XA], and Viangchan) increased, corresponding to the forest decline hotspot. Some provinces (such as the junction of Saravan and Champasak [CH]) and the border of Laos showed a significant reduction trend related to population migration and local policies. There were increasing trends in artificial surfaces along the Mekong River, the northwestern plateau, and the southern plain, and the cities in the northern LM province, the southern XA province, the northwestern Savannakhet province, and the AT province showed an increase. The hotspots with increased water bodies were in the northern hilly and mountainous areas (PH and Oudomsai provinces), and the center and southern Mekong River coastal regions, and the hotspots with dwindling water bodies were dispersed throughout Laos and had a significant decrease. The hotspots of wetland increase were mainly in the BL province in the central region, and other local areas, such as the central and southern regions, increased slightly. The forests, cultivated land, and artificial surfaces had the most extensive total area of change in LULC.

4.2. Changes in Ecosystem Service Value in Laos

4.2.1. Ecosystem Services Value Composition in Laos

Equations (2) to (4) were used to identify the ESV in Laos. As shown in

Table 3. Ecosystem services values for various types of land and their changes between 2000 and 2020 (10⁶ USD).

Year	Cultivated Land	Forest	Grass Land	Shrub Land	Wet Land	Water Bodies	Artificial Surfaces	Bare Land	Total
2000.00	127.95	1169.29	89.20	1.77	4.18	31.45	0.89	0.00	1424.72
2000/%	8.98	82.07	6.26	0.12	0.29	2.21	0.06	0.00	100.00
2020.00	156.23	1133.83	91.13	1.98	5.18	34.34	5.53	0.00	1428.24
2020/%	10.94	79.39	6.38	0.14	0.36	2.40	0.39	0.00	100.00
2020–2000	28.28	−35.46	1.93	0.21	1.00	2.89	4.64	0.00	3.94
2020–2000/%	1.96	−2.68	0.12	0.02	0.70	0.19	0.33	0.00	0.64

, the main contributions to ESV in Laos in 2000 and 2020 (about USD 142–143 billion) were forest, cultivated land, and grassland, collectively accounting for 97.31% of the total ESV. Forest accounted for about 53–54% of the land area, and its ESV accounted for about 79.39–82.07%. Agriculture was the third most prevalent land use type in Laos (about 12.7%), and the ESV of this land type ranged between 8.98 and 10.94%. Although the grassland area was small (<8.09% of the total land area), the grassland was prone to the internal transfer of natural or artificial landscapes and the reversal of artificial to natural landscapes. The contribution of grassland to ESV in Laos was close to that of cultivated land, accounting for roughly 6.2–6.3% of the ESV.

In order to more vividly and intuitively express the differences in the ESV of various provinces in Laos, this article uses the natural breaks (Jenks) method in ArcGIS to divide the ESV of Laos from 2000 to 2020 into five levels: lower, low, medium, high, and higher. Figure 5 shows the spatial distribution of the ESV in Laos in 2000 and 2020. The findings showed that areas along the Mekong River have higher ESV values, in addition to the western BK Province and to the northwest AT Province. This result was consistent with the unique LULC type and landform type distribution characteristics of the area of study, i.e., a large area of the floodplain distributed along the Mekong River. With the periodic changes in the flood and dry seasons, the floodplain was classified as unused land and had no ESV. The impact plain area around the Mekong River surrounded grassland and shrubland, and the cultivated land was more concentrated. These LULCs had little ESV. At the same time, the ESV in the mountainous areas characterized by large areas of forested land and grassland was higher, which was concentrated in the XI and HO provinces in the northeast of the study area, the PH province in the north, the LM province, the Xaisomboun province, and the BL province in the middle region. Areas of low ESV in 2020 showed an increasing trend compared with that in 2000, and there was an expansion in the area of low ESV year-on-year. Overall, there was a clear declining trend in ESV in the study area.

The research area has seen a sizable conversion of forests with high ESV into land types with low ecological service values, such as unoccupied land, due to increased anthropogenic activity and urban socioeconomic development. This was the main driver of the dramatic reduction in the ESV of forests in Laos over the last two decades. The increase in grassland area in the central (the junction of the BL and Khammouan provinces) and southern regions (the CH and AT provinces) due to water resource development was primarily responsible for the gain in the plaque distribution area. This could be attributed mainly to the expansion of water bodies and grassland following ecological restoration; there were also a few gain regions with point distribution in the western portion of the study area. The constant promotion and execution of forest conservation measures, which have expanded the forest covering in some regions, are primarily responsible for the gain area of high ESV in the northeastern section of the research area.

4.2.2. Changes in the Ecosystem Service Value

Between 2000 and 2020, the total ESV in Laos increased by USD 3.94 million (Table 2). Among them, the value increment contribution mainly came from cultivated land (about 1.96%), which was followed by wetlands (0.7%), artificial surfaces (0.33%), and water (0.19%). The value reduction contribution came from the forest (−2.68%). Among first-category ESV (

Table 4. Changes in the ecosystem services value from 2000 to 2020 in Laos (USD 10⁶).

First Category	Second Category	2000	2000/%	2020	2020/%	2020–2000	2020–2000/%
Provisioning services	Food Production	122.99	8.63	134.11	9.39	11.12	0.76
	Raw Materials	24.55	1.72	25.16	1.76	0.61	0.04
Regulating services	Gas Regulation	2.80	0.20	2.73	0.19	−0.07	−0.01
	Climate Regulation	454.97	31.93	444.30	31.11	−10.66	−0.83
	Disturbance Regulation	14.84	1.04	14.52	1.02	−0.32	−0.02
	Water Regulation	21.60	1.52	23.52	1.65	1.92	0.13
Supporting services	Water Supply	20.97	1.47	23.29	1.63	2.32	0.16
	Erosion Control	77.11	5.41	75.57	5.29	−1.55	−0.12
	Soil Formation	15.32	1.07	17.93	1.26	2.61	0.18
	Nutrient Cycling	0.93	0.07	0.98	0.07	0.05	0.00
	Waste Treatment	39.64	2.78	41.23	2.89	1.60	0.10
	Pollination	7.78	0.55	7.72	0.54	−0.07	−0.01
	Biological Control	3.97	0.28	4.12	0.29	0.15	0.01
	Habitat/Refugia	35.10	2.46	35.53	2.49	0.43	0.02
	Genetic Resources	380.05	26.68	375.97	26.32	−4.07	−0.35
Cultural services	Recreation	197.54	13.87	196.87	13.78	−0.68	−0.08
	Cultural	4.37	0.31	4.51	0.32	0.15	0.01

), the supporting services contributed about 40%, and the regulating services accounted for about 34%, significantly higher than that of cultural services (about 14%) and provisioning services (about 11%). Moreover, for the second-category types of ESV (Figure 6), food production, soil formation, and water supply increased, and climate regulation, genetic resources, and erosion control decreased. It is worth noting that the ESV of artificial surfaces in Laos has increased slightly over the past 20 years, consistent with Figure 4a. The low-value clustering of artificial surfaces in Laos is pronounced, indicating that artificial surfaces have remained stable in most areas except for a few that have expanded over the past 20 years and have even degraded in some areas far from the country’s economic and political centers. This phenomenon has increased the recreation and cultural services provided by artificial surfaces and promoted the increase in ESV of other natural land types.

4.3. The Impact of Land Use and Land Cover Changes on Ecosystem Service Values

Figure 7 reflects the deteriorated contribution rate of ESV in Laos from 2000 to 2020. (1) Cultivated land. During the study period, cultivated land had the most significant positive contribution to the deteriorated contribution rate of ESV. This shows that the main reason for the continuous changes in ESV in Laos from 2000 to 2020 is the continuous change in cultivated land area. (2) Forest. Forest has the most considerable deteriorated contribution rate to ESV, but it is a negative contribution and is the only negative contribution among all LULC types. In the past 20 years, the forest area in Laos has been dramatically reduced and transformed into other land types, especially the transformation into cultivated land and grassland, which is the main factor leading to this result. The forest is a type of LULC with apparent market regulation, and a stable ecological environment helps the forest continue to play an essential role in regional ESV contribution. (3) Grassland. Grassland also has a relatively large area in Laos. However, the transfer area of grassland in the past 20 years is small and mainly between grassland and forest. Therefore, ESV’s forward deteriorated contribution rate is low, only 48.98%. (4) Shrubland. The area of shrubland changes minimally and is a transitional type between forest and grassland, resulting in its deteriorated contribution rate to ESV being only 5.33%. (5) Wetland. The deteriorated contribution rate of its changes to the ESV is positive, but the contribution is negligible. (6) Water. Laos is a landlocked country, and the remaining water areas, except the Mekong River, are small and change with the seasons. The deteriorated contribution rate of positive ESV is 73.35%. (7) Artificial surfaces. The deteriorated contribution rate of its changes to the ESV is a positive contribution of 117.77%, second only to cultivated land. However, this is based on the continued increase in the area of artificial surfaces, which is at the expense of occupying cultivated land and forests. Since the service value of natural ecosystems will decrease during the transformation process into artificial ecosystems, the positive contribution of artificial surfaces should be viewed correctly. (8) Bare land. The ESV coefficient of bare land is 0 in this study, so the deteriorated contribution rate of its changes to the area also is 0. However, attention needs to be paid to the issue that, due to economic development in Laos, reserve land resources have been further developed, and the amount of resources has become less and less.

5. Discussion

The present study used Laos, a typical landlocked country, as a case study to investigate the driving factors of changes to the ESV and the advantages and disadvantages of applying the Costanza value coefficient at the national or regional scale. The study’s findings benefit current macro-scale related research and can provide a more scientific and rigorous theoretical basis for local LULC and ecological and natural sustainable development.

5.1. Analysis of the Drivers of Changes in the Ecosystem Services Value

Numerous variables regulated the LULC patterns and ESV of Laos. The present study distinguished between factors that indirectly and directly influenced changes in the LULC and ESV in Laos.

5.1.1. Direct Factors

The first direct factor is the timber industry. Timber is one of the essential industries of Laos’ export trade, contributing to Laos’ economic development and construction [39]. However, to maximize benefits in recent years, some timber developers in Laos have conducted illegal deforestation of forest resources, exacerbating the speed of forest depletion in Laos. Consequently, the forest resources in Laos are facing tremendous pressure, which also weakens the foundation of Laos’ timber industry development. Moreover, the relevant laws and regulations are limited and cannot effectively protect forest resources. Forests offer significant ESV. Therefore, the decline in forest cover was dominant in lowering ESV in Laos.

The second direct factor relates to the use of outdated farming methods. About 30% of people in Laos live in poverty [40]. They live in rural areas and rely on natural resources and nomadic agriculture. Nomadic farming is an ancient way of agriculture, but it is very destructive to ecological protection and social development [41]. For instance, burning mountain forests in northern Laos and nomadic activities are the leading causes of Laos’s forest, grassland, and shrubland degradation. Additionally, the primary cause of the decline in forest cover in central and southern Laos is the unsustainable use and management of forests by individuals who willfully clearcut economic forests and woodlands. Thus, ESV provided by natural types of LULC has been trending downward due to a rise in ecological degradation and natural environment deterioration caused by the yearly loss of forests.

5.1.2. Indirect Factors

The first indirect factor is poverty and population growth. Southeast Asia’s only landlocked country is Laos. Decades of war and post-war influence have left most of Laos’ population impoverished [42]. Therefore, the degree of land change is related to population density. Due to their livelihoods, the rapidly growing rural population carries out the original agricultural planting activities in forests, which include slash and burn activities, leading to severe destruction and degradation. This results in ecological and environmental damage, ecological hazards, and the decreased natural LULC-type values of ESV.

The second indirect factor is economic activities. Regional development is affected by the economy and population, and the environment is disturbed by socioeconomic activities. For example, some local authorities in Laos have previously approved logging plans for domestic and foreign investors in exchange for funding for infrastructure construction or development of urban areas [43]. Thus, the excessive demand for wood has put tremendous pressure on Lao government departments and led to a lack of sustainability in the land and forest use plans. Therefore, coordinating economic development and protecting forest resources is a significant problem in Laos.

The third indirect factor is governance. The Lao government has implemented a unified distribution of land use measures [44], which have significantly contributed to preserving the stability of LULC. However, government agencies need to be more decisive in planning, supervising, and implementing LULC development due to the absence or limitations of pertinent laws and regulations and the need for qualified personnel and financial assistance. Formulating sustainable LULC policies that meet the actual development needs of Laos is one of the fundamental ways to maintain the stability of ESV in Laos.

5.2. The Ecosystem Services Value and Sustainable Development in Laos

ESV at the macro level only slightly increased because of minor alterations in LULC in Laos between 2000 and 2020. However, these alterations caused a shift in the value transfer between the ESV categories. This was mainly reflected in the increase in forest area in the north, wetland and shrubland in the middle, and the increase in regulation and support of the ESV. This masked the decrease in the regulation and support of ESV due to the increased areas of bare land and artificial surfaces and the decline in the grassland area. However, the ecological functions of the natural landscape units, such as the wetlands, forests, and grasslands, differ. One strategy is to focus on the advantages and disadvantages of the overall ES and their changing trends in ESV. Under this approach, the risk of the corresponding ecological function reduction due to the reduction in forest and grassland areas is not apparent [45]. However, if the bare land area continues to increase, the imbalance between the first- and second-category ES, in particular, might result in significant changes to Laos’ overall ES. This would influence the country’s ability to maintain ecological security and conserve biodiversity [46]. Land use change from natural environment to artificial landscape frequently occurs due to population growth, industrial agglomeration, and urbanization. An example is converting the forest and grassland surrounding cities to cultivated land and artificial surfaces [47]. Consequently, in terms of spatial planning, it is essential to balance and coordinate ecological services when allocating space and creating spatial patterns for each LULC category [48].

Laos is the single inland country in Southeast Asia, and it is a global biodiversity hotspot with high biodiversity and conservation value [49]. Recent economic expansion and population growth, especially in the central and southern plains and along the Mekong River, rapid agricultural development, and rapid urbanization have all contributed to Laos’ severe ecological problems. These issues include the deterioration of the quality of ecological resources such as land, energy, and water, and the intensification of resource and environmental constraints [50]. The demand for clean air, water, green space, and other ecological environments is rising concurrently with improving living conditions. Thus, ecosystem regulation and support service functions are significant in ensuring Laos’ ecological security and biodiversity protection. China and Laos’ “Belt and Road Initiative”, the China and Laos railway, and other major cooperation projects continue to advance, and it is expected that the future regional development of Laos will further expand the demand for land, with the effect of changes in LULC on ES inevitably being more significant than in the past. Therefore, providing the necessary ES and curbing the excessive ecological footprint growth is particularly critical. Moreover, there is a need to protect the natural mountains, green spaces, wetlands, and bare farmland with ecological value, strictly prioritize optimizing LULC and landscape patterns, and promote the formation of safe and reliable ecosystems. The ecological security support system is also a focus of the international community’s attention.

5.3. The Advantages and Disadvantages of the Use of the Costanza Value Coefficient at a National/Regional Scale

At both national and regional levels, the Costanza value coefficient is commonly used to evaluate how changes in LULC affect the ESV [51], and it can give researchers thorough and helpful information to enable the assessment of the regional ESV. Its advantages are that it has lower data requirements and good results comparability, and it consists of a thorough evaluation, relatively simple procedure, and simple operation. Furthermore, it does not require complicated model calculations or questionnaire surveys. Consequently, it can be utilized as a quick accounting technique to estimate the ESV at the national and regional levels. It may also be used to assess the dynamic changes in the ESV based on variations in the LULC types and trends. However, the Costanza value coefficient is based on the estimation results of the global introductory ecosystem situation survey [52] and depends on the ecological service base equivalent table per unit area. The demand orientation of the development of various countries/regions in the world is different, and ecosystems are complex, dynamic, and heterogeneous. Consequently, the main functions provided by the same ecosystem will differ in different regions at different times [53], resulting in errors in estimating ESV and affecting the evaluation accuracy. Therefore, the correction between the equivalent factor coefficient under different time–space conversion conditions is worthy of further exploration, and it is also necessary to verify the consistency between obtained results and actual service value through field research. Additionally, because of the method’s substantial reliance on the system for classifying LULC, changes in the ecosystem function and the consequences of improved LULC classification will impact the evaluation. Moreover, the change in the value does not always result from a change in the type of LULC when the method is used to evaluate the effects of changes in LULC on ecosystem service valuations. It could also be caused by changes in the biomass of an ecosystem or a change in the currency’s value. Therefore, when determining the national- and regional-level ESV, the Costanza value coefficient technique should be treated as an estimate [12].

In addition, research based on material quality models such as InVEST [54], ARIES [55], and SoIVES [56] is also emerging, which provides new technical means for ecosystem value assessment research. Among them, the InVEST model has numerous uses and is frequently employed in domestic and international research [57]. There is a further need to verify and comprehensively apply various different ESV methods. The accuracy of ESV can be improved by cross-validation of the different valuation methods, particularly by focusing on a single ESV. This approach can also help evaluate the advantages and disadvantages of the different methods and in the selection of methods with regional applicability. The principle of complementary advantages can be fully utilized in valuing complex ecosystems by applying multiple valuation methods. The InVEST model mainly evaluates individual ES and requires accurate inputs of temperature, precipitation, soil, and other socioeconomic data [58]. While the different methods provide different estimates of ESV, the present study focused on the impact of LULC change on ESV in Laos in 2000, 2010, and 2020. The present study evaluated variations in overall ESV over the past two decades, focusing mainly on relative changes in ESV. This approach should have fully considered the effects of different estimation methods on the absolute ESV. However, as Laos’ primary research and monitoring could be more robust, the current data could not support model operations with high data quality requirements. Therefore, at this stage, the value assessment based on the Costanza value coefficient is still the best method for developing countries such as Laos to assess the value of services provided by the ecosystem.

6. Conclusions

(1) The main types of LULC in Laos were forest and shrubland, accounting for about 85% of the land area of Laos. There was only a minor change in LULC during the study period. The area of forest decreased, the areas of artificial surfaces, bare land, cultivated land, grassland, shrubland, water, and wetland increased, and the transfers between cultivated land, forest, and artificial surfaces were the most significant.

(2) In 2020, ES in Laos had a total value of about USD 142.824 billion, increasing by USD 352 million throughout the study. The forest ESV accounted for about 79.39%, and that of cultivated land and grassland accounted for about 17.32%. Among the first categories of ES, provisioning services increased, and there were decreases in regulating and cultural services while supporting services remained unchanged. For the second category, except for the service value of nutrient cycling, which remains unchanged, the values of the other secondary types of services decreased.

(3) Changes in land use in Laos had a minimal effect on the ecosystem’s overall value and first-category ES over the study period. The overall value of the ES that Laos provided remained consistent. However, the value of the second-category ES was reduced, putting pressure on Laos to maintain ecological security and biodiversity preservation. Moreover, exploring the effects of LULC change and climate change on ES and the trade-off and synergistic response mechanism between the two will become a problem that must be addressed in Laos’s social and economic construction.

(4) The ESV was found to be specifically impacted by changes in LULC, which affected how the elasticity value and deteriorated contribution rate of ecosystem service value changed. In particular, the higher the value coefficient, the more significant the impact on the types of land. However, the elasticity analysis can only justify the significance of various LULC forms according to their contributions to LULC. It cannot be applied to assess the coefficient ESV robustness and elasticity. Thus, this challenging issue requires further research.