A Study on the Gains and Losses of the Ecosystem Service Value of the Land Consolidation Projects of Different Properties in Hubei Province: An Empirical Comparison Based on Plains, Mountains and Hills

Abstract

In view of the differences of land use structure and ecological environment changes caused by land consolidation projects with different features and landforms, this paper uses the modified ecosystem service value estimation model to quantitatively evaluate the change patterns of the ecosystem service value (ESV) of land consolidation, development and arrangement projects in Hubei Province under plains, hills and mountains to provide a theoretical basis for the ecological transformation of land consolidation. The results show that, compared with the pre-land consolidation period, (1) the total amount of ESV in the land consolidation project areas has increased, whereas the land development and arrangement project areas have decreased. Under the same nature, the growth rate of land consolidation project areas is as follows: hills < plains < mountains, and the loss rate of land development and arrangement project areas are as follows: mountains > plains > hills and hills > mountains > plains, respectively. Under the same landform, the total loss rate of ESV in land development project areas is slightly lower than that in land arrangement project areas. (2) The total amount of ESV in the land consolidation project areas under different natures and landforms of the supply service function shows a decreasing trend, and the total amount of ESV of the adjustment service, support service and cultural service function shows an increasing trend in the land consolidation project areas, whereas the land development and arrangement project areas show a decreasing trend. There is an obvious value transformation process of “ecology for production” in the land development and arrangement areas.

1. Introduction

Ecosystem services can be seen as a complex process, which can help humans obtain some environmental effects from ecosystem structures, processes and functions in order to meet their survival needs [1]. Ecosystem service value (ESV) represents the economic value of an ecosystem’s service functions [2], which plays a crucial role in promoting the coordination between humans and nature and in establishing a green national economic accounting system [3,4]. Costanza et al. (1997) divided the global terrestrial ecosystem functions into 17 categories, estimating the global ecosystem service values by establishing the value equivalent of ecosystem services per unit area to lay the foundation for future studies in the field of ESV [5]. In recent years, many scholars have employed many methods to evaluate the ESV of global, regional and watershed ecosystems and individual ecosystems (e.g., forests, wetlands and grasslands), such as the willingness to pay method, cost–benefit method, alternative cost method, travel cost method, hedonic value method and opportunity cost method [6,7,8,9,10]. Existing research has investigated many driving factors of ESV, such as rapid urbanization [11,12,13], land use change [14,15], spatial structure and morphological changes in natural landscape [16,17]. Therefore, ESV is one of the burning topics in the area of ecological economics and environmental economics [18,19].

The land is the carrier of the terrestrial ecosystem, and changing its land use structure can affect the ecosystem, which may harm the gains and losses of ESV [20]. Land consolidation is an activity of the comprehensive treatment of fields, water, roads, forests and villages with a series of biological and engineering measures. The implementation of land consolidation can inevitably change the structure or patterns of regional land use, thus affecting some environmental elements (e.g., soil [21], water [22], vegetation [23], atmosphere [24] and biodiversity [25]) and landscape patterns [26,27], which have direct or indirect as well as positive or negative impacts on regional ecosystems and their processes [28,29,30]. Therefore, how to effectively quantitatively assess ecological environment changes in land consolidation project areas is conducive to promoting the ecological transformation of land consolidation and to improving the regional ecological environment. For example, by introducing the remote sensing ecological index (RSEI) and constructing an ecological quality change assessment model, some scholars revealed the time change pattern of the impact of land consolidation on regional ecological environment quality from negative to positive effects [31,32,33]. Feng et al. [34] established a quantitative evaluation model of ecological safety effects from four aspects (dam safety, slope stability, efficient cultivation and effective management) and scientifically measured the ecological safety effects of land consolidation area. In recent years, some scholars have also assessed the ecological effects of land consolidation by estimating the gains and losses of ESV in the land consolidation project areas. For example, some scholars adopted the equivalent correction method and single service evaluation method to evaluate the gains and losses of ESV in land consolidation project areas from the perspective of landform type, regional scale, project type and consolidation pattern, and they proposed an environmental protection pathway for land remediation areas [35,36,37,38,39]. Zhong et al. [40] investigated the impact of land consolidation on the mechanisms of synergistic synergies and trade-offs between the three ecosystem services (crop productivity, carbon storage and soil conservation). However, existing research ignores that the connotation of land consolidation includes the concepts of land reclamation, development and arrangement. Thus, the gains and losses of ESV have been neglected, and the existing research cannot demonstrate systematic results in the area.

From the literature [41], it is known that land arrangement is the activity of taking administrative, economic and legal measures to comprehensively improve fields, water, roads, forests and villages in a certain area; adjusting and transforming land use conditions; redistributing land resources; improving land quality and land use efficiency; increasing effective arable land area; and improving production, living conditions and the ecological environment. Land development is the activity of making unused land available through engineering, biological or comprehensive measures. Land consolidation is the activity of improving damaged land by production and construction activities and of making natural disaster areas available by taking comprehensive improvement measures. There are some common grounds and differences between the impact of land arrangement, development and reclamation on the regional ecological environment. For example, corridor width and connectivity in the project area is enhanced, and the landscape fractal dimension is reduced after land arrangement and reclamation. The largest patch area increases and decreases, respectively, in the land arrangement and reclamation project area. Moreover, the patch density, biodiversity and ESV decrease slightly in the land consolidation area, whereas they show a slight increase in the land consolidation project area [42,43]. Although the amount of cultivated land is enhanced during land development, it reduces the diversity of the original surface landscape and the stability of the ecosystem, which is unsustainable [44]. Consequently, it is of great theoretical and practical significance to conduct a comparative study on the gains and losses of the ESV of the land consolidation projects of different natures.

Hubei Province is one of the key strategic areas of land consolidation in China. According to the geomorphic types, the land consolidation in Hubei Province can be divided into three types, i.e., Eastern Hubei with low mountains and hills (hills), Central Hubei with plains (plains) and Western Hubei with plateaus and mountainous areas (mountains) [45]. Some studies have indicated that there exist differences in the gains and losses of ESV in the plains, hills and mountains of Hubei Province after land consolidation [35,36,37], and it is greatly influenced by the scale of land consolidation [20,36]. Therefore, this paper selects typical land arrangement, reclamation and development projects with different scales in the plains, hills and mountains of Hubei Province, and it employs the improved equivalent factor method to reveal the patterns of the gains and losses of ESV of land consolidation projects with different properties and landforms. The paper adds to the rapidly expanding field of land consolidation projects and enriches the theoretical system of ESV, which is conducive to promoting the ecological transformation of land consolidation and laying a theoretical foundation for regional sustainable development.

2. Theoretical Analysis

2.1. The Mechanism of the Impact of Land Consolidation Projects on ESV

Land consolidation primarily has an impact on the regional ecological environment through land leveling, field roads, irrigation and drainage, farmland protection and environmental protection, resulting in the gains and losses of ESV. The specific process is shown in Figure 1.

• Affected by regional ecological environment elements. (1) The impact of land consolidation on the soil. Firstly, for land leveling projects, on the one hand, some measures (e.g., large machinery, vehicle transportation, field consolidation, earth landfill and land tillage) may lead to soil hardening, the exposure of soil surface, the aggravation of the loss of soil fertility, reductions in land production capacity and the cause of ESV loss. On the other hand, it can transform soil porosity and its profile structure, thus ameliorating soil quality and promoting ESV. Secondly, for irrigation and drainage projects, improved irrigation and drainage facilities can reduce soil salinity, improve soil physical properties, reduce soil erosion and the risk of waterlogging and drought in farmland and improve soil output, thus enhancing ESV. In parallel, poor facilities can aggravate soil salinization, harm soil production capacity and cause the loss of ESV. Thirdly, for the farmland shelterbelt projects, the new shelterbelt can effectively protect farmland from disasters (e.g., wind and sand) and prevent the loss of soil fertility, thus improving farmland output and ESV. (2) The impact of land consolidation on the hydrological environment. On the one side, the construction of large-scale water conservancy projects alter the regional hydrological characteristics. The self-purification capacity of downstream rivers is harmed when protecting the water source of farmland irrigation. Against the background, the loss of soil and water is aggravated, thus causing gains and losses of ESV. On the other side, the hydrological adjustment measures in the pit area may aggravate the loss of ESV in the pit area, and on the other hand, the hydrological adjustment measures in the pit area may cause obvious losses. On the one hand, the construction of large-scale water conservancy projects in irrigation and drainage projects change the regional hydrological characteristics. While ensuring the water source of farmland irrigation, it may reduce the self-purification capacity of downstream rivers, aggravate regional soil and water loss or water pollution and cause the gains and losses of regional ESV. On the other hand, measures such as pit and pond landfill in land leveling may significantly reduce the regional hydrological regulation capacity, aggravate the imbalance of regional hydrological conditions and lead to the loss of ESV. (3) The impact of land consolidation on regional climate. Land leveling projects, farmland shelterbelt projects and irrigation and drainage projects affect the evaporation of water when changing the regional vegetation coverage and water allocation, and they affect soil resources, which cause some changes in regional precipitation and local temperature. Therefore, there are gains and losses of ESV. (4) The impact of land consolidation on vegetation. On the one hand, the farmland shelterbelt projects have effectively classified regional vegetation into more types and have developed the vegetation coverage, which is beneficial to the enhancement of ESV. On the other hand, the cutting of vegetation or weeds in land leveling projects or irrigation and drainage projects significantly reduces the regional vegetation coverage or vegetation diversity, resulting in the loss of ESV. (5) The impact of land consolidation on biodiversity. On the one hand, land leveling projects, field consolidation and the construction of ditches and rural roads expand the survival area of regional animals, which is conducive to strengthening population exchange, increasing biodiversity and enhancing ESV. On the other hand, environmental pollution (e.g., road hardening and noise) is generated by construction and can ruin the regional biological living environment, reduce biodiversity and decrease ESV. In parallel, the consumption of sand, cement, gasoline and diesel increases the concentration of atmospheric carbon emissions, thus cauing gains and losses of ESV.
• Affected by land use structures. After land consolidation, the amount of cultivated land and transportation land increases, whereas others decrease a lot. Some types of land that have an indispensable impact on ESV, such as woodland, pits, ponds and wasteland, are transformed into cultivated land, causing the loss of ESV. Moreover, reductions in land use diversification affect the stability and anti-interference ability of land and even harm the amount and species of microorganisms. Although increases in transportation land facilitate human cultivation and land development, biodiversity is hindered a lot. In addition, land consolidation turns some types of land, such as sandy land, bare land and abandoned land, into cultivated land. Planting forests to effectively protect the ecological environment is beneficial to the improvement of ESV as well.
• Affected by regional landscape patterns. Ditch and rural road construction as well as other measures in land consolidation involve patches and corridors in the land’s landscape, resulting in changes in the regional landscape pattern [21], such as reduced fragmentation and improved corridor connectivity. On the one hand, it has expanded the living area of farm animals, expanded the contact and exchange of different organisms, increased biodiversity and improved ESV. On the other hand, the farmland ecosystem is relatively common, the regional landscape heterogeneity is reduced and ditches and rural roads are mostly hardened with cement. Therefore, the channels of some farmland animals lead to the distinction of animals, resulting in reductions in biodiversity and decreases in ESV.

2.2. The Difference in the Effects of Different Land Consolidation Projects on ESV

In addition to the common effects of land consolidation projects, the effects of land arrangement, development and reclamation projects on ESV have their own characteristics due to the different characteristics of land consolidation projects (Figure 1). (1) Land consolidation mostly occurs in mature farming areas, and its consolidation focus is dominantly the comprehensive consolidation of fields, water, roads, forests and villages. On the one hand, the consolidation of abandoned residential areas and the integration of dilapidated rural roads can effectively increase the area of cultivated land, thus ameliorating regional production conditions and enhancing ESV. On the other hand, due to the imperative role of pits, ponds, woodlands and grasslands, regulating the ecosystem and consolidate it into cultivated land is significant, which is conducive to decreasing ESV. (2) The land damaged by production, construction activities and natural disasters is the main type of land that needs land consolidation. Before consolidation, it is mainly in a wasteland state. Therefore, land consolidation can improve the diversity of land use in the project area, enhance the efficiency of land use and improve ESV. (3) The impact of land development projects on ESV varies a lot with different development goals. On the one hand, developing wasteland into cultivated land or making it available can enhance ESV. On the other hand, the cultivated land can be affected greatly by regional climate and hydrology compared to other types of agricultural land, resulting in a significant reduction in ESV. Theoretically, the impact of land development and land consolidation on ESV is mostly negative, whereas land consolidation is mainly positive. Thus, it is of necessity to evaluate the gains and losses of ESV and to compare the ESV among different land consolidation projects.

2.3. The Different Effects of Land Consolidation Projects of Different Landforms on ESV

Due to the different characteristics of land use structures, the impact of land consolidation projects of different landforms on ESV varies a lot (Figure 1). For plains, the terrain is relatively flat, the natural environment and farmland infrastructure are in good condition, the land use is intensive and most of the land is cultivated land. Land consolidation is mostly based on the internal potential tapping method, which involves minor changes to the local terrain, hydrological characteristics and land use structure. The impact on ESV is altered critically due to reductions in the area of pits, ponds and sporadic wasteland. For mountains, the terrain fluctuates greatly, the efficiency of land use is relatively low, and the ecosystem is fragile. Most of the land is forest. The land consolidation type of changing forests into farmland has an indispensable effect on the environment, which can aggravate soil erosion and water, which demonstrates a significant impact on the gains and losses of ESV. The characteristics of hills are between those of plains and mountains, and their impact on ESV changes according to the levels of land use. On the one hand, in the low hill gentle slope area dominated by medium and low-yield fields, land consolidation can significantly improve the regional production conditions, increase the quantity and quality of cultivated land and significantly enhance ESV through the construction of terraces. On the other hand, in the low mountains and hills dominated by forest land and grassland, land consolidation has a great effect, which is conducive to causing the loss of ESV. Therefore, it is of significance to compare the evaluation of the profits and losses of ESV before and after land consolidation.

In conclusion, the impact of land consolidation projects with different properties and landforms on ESV varies a lot. Changes in land use structure can affect ESV in the long term; therefore, considering the temporary effects of the implementation of land consolidation projects on the ecological environment and the availability of data, this paper focuses on the gains and losses of ESV caused by variations in land use structure.

3. Study Area, Data Sources, and Research Methods

3.1. Overview of the Study Area and Empirical Model

Hubei Province is located between 29°05′~33°20′ N and 108°21′~116°07′ E. It is located in the hinterland of Central China and the middle reaches of the Yangtze River, adjacent to Anhui Province in the east, Jiangxi Province and Hunan Province in the south, Chongqing City in the west and Henan Province in the north. With its superior geographical location, Hubei Province is a fulcrum and promotes the strategy of the rise of Central China. The total area of Hubei province is 18.59 × 10⁴ km², with 17 prefectures (cities or prefectures) and 103 counties (cities or districts). The territory has various geomorphic types, including mountains, hills, hillock areas and plains, accounting for 44.4%, 22.6%, 13.1% and 19.9% of the area, respectively. With abundant hydrothermal conditions and moderate soil pH values, Hubei province is not only an important grain, cotton and oil production base in China, but it is also one of the most important strategic zones of land consolidation in China.

According to the principles of the consistency of natural conditions, such as landforms, economic and social conditions and agricultural constraints, the Department of Natural Resources of Hubei Province divided land consolidation in Hubei Province into three project types. The first is the project-type area of low mountains and hills in Eastern Hubei, including Huanggang City, Huangshi City and Xianning City. The second is the project-type area of the Central Hubei plains, including Jingzhou City, Wuhan City, Jingmen City, Xiangyang City, some cities and counties of Xiaogan City, as well as Xiantao City and Qianjiang City directly under the provincial administration. The third is the mountainous engineering-type area of the Western Hubei plateau, including Shiyan City, the low mountain and river valley of Yichang City, Pingba and the river valley of Enshi Tujia Miao Autonomous Prefecture [45].

According to a statistical account of the land consolidation projects of the Hubei Provincial Department of natural resources, Hubei province carried out 1972 land consolidation projects from 2002 to 2016, including 1761, 52 and 159 in land arrangement, reclamation and development projects, respectively, with an average construction scale of 981, 163 and 649 hectares, respectively. This paper selects different land arrangement and reclamation projects. In this paper, X_ij, Y_ij, and Z_ij represent different land consolidation projects. X, Y and Z represent different land arrangement, development and reclamation projects, respectively. i = 1, 2 and 3, representing plains, mountains and hills, respectively. j = 1, 2 and 3, representing large-scale (greater than the average construction scale), medium-sized (close to the average construction scale) and small-scale (lower than the average scale) construction projects, respectively. Their locations and basic information are shown in Figure 2 and

Table 1. The basic situation of typical land consolidation projects in Hubei Province.

Project Code	Construction Scale (hm2)	Investment Scale (×104 USD)	Newly Cultivated Land Scale (hm2)	Start Date (Year/Month)	Completion Date (Year/Month)
X11	174	149	165	2011/4	2011/6
X12	143	93	128	2012/2	2015/7
X13	69	49	65	2014/3	2016/6
X21	50	45	45	2012/2	2012/6
X22	42	23	39	2011/10	2012/9
X23	21	18	20	2011/10	2012/9
X31	467	418	275	2011/10	2012/9
X32	168	89	100	2011/11	2012/11
X33	53	48	46	2012/1	2012/6
Y11	4596	1286	186	2011/10	2012/10
Y12	2300	634	93	2011/9	2013/8
Y13	665	297	228	2011/1	2011/12
Y21	1306	584	995	2011/12	2012/11
Y22	1000	447	301	2012/11	2013/10
Y23	400	179	121	2012/10	2013/9
Y31	2000	894	602	2012/10	2013/9
Y32	1333	596	400	2012/10	2013/9
Y33	589	263	178	2013/11	2014/10
Z11	3256	1048	100	2011/10	2012/9
Z12	2066	665	62	2011/12	2012/11
Z13	1000	322	30	2011/10	2012/10
Z21	1333	728	41	2012/10	2014/9
Z22	804	436	24	2011/12	2012/11
Z23	307	164	9	2011/10	2012/9
Z31	4509	2146	136	2011/9	2013/9
Z32	2733	1071	83	2012/12	2014/10
Z33	1000	447	300	2011/10	2012/10

.

3.2. Data Source and Processing

The data of typical land consolidation projects in this paper are from the planning and acceptance account data of land consolidation projects from 2002 to 2016 provided by the Department of Natural Resources of Hubei Province. The data of grain output, planting area, cost–benefits and rainfall in China and Hubei Province are derived from the Hubei Statistical Yearbook (2011−2018), the China Statistical Yearbook (2011−2018), a national compilation of cost–benefit data of agricultural products (2017−2018) and the China Water Conservancy Statistical Yearbook (2011−2018).

Considering that the commencement of land consolidation projects is generally in the slack period, the cycle of projects varies a lot. In order to evaluate ESV accurately, this study takes the year before commencement and the second year after the completion of the land consolidation projects as the beginning and end, respectively.

3.3. The Method of the Evaluation of the Gains and Losses of ESV of Typical Land Consolidation Projects

For the assessment of ecosystem service functions, the study by Costanza et al. [5] clarified the principles and methods of ESV estimation in a scientific sense, and their equivalent factor method for ESV per unit area has the advantage of being simpler and more efficient than other ESV assessment methods. However, some of the data in this study are biased and need to be corrected according to regional practice. Xie et al. [46] divided them into 4 categories (i.e., supply, regulation, support and cultural services) and 11 subcategories according to the situation in China and the opinions of experts. They revised them to the national scale and constructed a spatio-temporal dynamic framework of ESV. In view of this, based on the existing study [46], this study uses the modified equivalent factor method to assess the gains and losses of the ESV of land consolidation projects under different properties and landforms in Hubei Province. The amendments are as follows:

3.3.1. Determination and Revision of Ecosystem Types

The types of land use in the typical land consolidation projects can be divided into 10 types: paddy field, dry land, garden (including orchard and tea garden), forest land (including sparse forest land, immature forest land and nurseries), pit ponds, ditches, wasteland, rural roads, construction land (water-bearing construction land, residential areas and independent industrial and mining land) and others (including ridges, bare land and disaster-damaged cultivated land). The areas have changed through land consolidation projects (the area of paddy fields, dry land and rural roads has increased, and the area of other land types has decreased), as shown in

Table 2. Changes in land use area before and after consolidation in typical land consolidation project areas in Hubei province. Unit: hm².

Land Use Type	Land Reclamation				Land Development				Land Arrangement
	Before	After	Increments		Before	After	Increments		Before	After	Increments
Paddy fields	0	697	697		2458	2730	272		5691	5880	189
Dry land	0	224	224		6442	8300	1858		4607	5159	552
Gardens	0	0	0		18	7	−11		254	235	−19
Woodland	0	3	3		868	269	−599		403	136	−267
Pits	0	0	0		258	177	−81		2222	2127	−96
Ditches	41	29	−12		594	532	−62		479	438	−41
Barren grassland	0	0	0		1447	66	−1381		347	190	−158
Rural roads	28	48	20		256	299	43		282	313	31
Construction land	0	2	2		18	0	−18		157	91	−66
Other land	947	13	−934		475	453	−21		683	558	−125

Note: The areas of the land use types in the figure were obtained by summarizing the nine typical projects.

. Existing research has divided the types of the ecosystem in the project area into five categories and six subcategories, including farmland (dry land and paddy fields), forests (broad-leaved forests), grassland (meadows), deserts (bare land), and water areas (water systems) [46]. Based on the situation of land use in the project area, the land use types are classified into ecosystems, and the land use types that do not belong to typical ecosystems are revised as follows: (1) paddy fields, dry land and forests land are classified into paddy fields, dry land and broad-leaved forests, respectively. Rural roads and others are classified into bare land. (2) The water surface ecological regulation function of pits and ponds is similar to that of rivers, so it is classified into water ecosystems. (3) Since the value of the garden is between forests and grassland, the value of the various ESV functions of gardens is taken as the average value of broad-leaved forests and meadows [47]. (4) The value of the regulation, support and cultural service function of ditches is taken as the average value of the corresponding value of paddy fields and bare land, and the value of the supply service function is taken as zero [35]. (5) The density of trees in the wasteland is less than zero. The surface layer is soil, weeds and other grasslands that are not used for animal husbandry. Therefore, the value of various ecological service functions is evaluated based on the average value of meadows and bare land [35]. (6) The changes in the ESV of construction land are not apparent, so the value of various ecological functions is evaluated at zero [35,38].

3.3.2. Equivalent Correction Method Based on ESV

This paper calculates the ESV equivalent of Hubei Province from 2010 to 2017 through regional correction and determines the benchmark equivalent value and ecosystem service unit price. According to the variations in land use type and area, by calculating the ESV before and after land consolidation, gains and losses of ESV can be evaluated. The calculation process is as follows:

(1)

Correction of regional coefficient based on farmland

Zhou et al. [47] believed that biomass can reflect the differences in ESV among various ecosystems, which can be reflected by replacing biomass with average grain yield, and they employed precipitation to correct the water resource supply and hydrological regulation service equivalent. Therefore, by adopting this method for reference, this study modifies the basic equivalent table of terrestrial ESV [46] by adopting the average precipitation and average grain yield over the years in Hubei Province and China. Based on this, the basic equivalent table of terrestrial ESV in Hubei Province from 2010 to 2017 was established. The formulas are as follows:

$$a_t=G_t^{\prime }/G_t or W_t^{\prime }/W_t$$

(1)

$$E_{ijt}^{\prime }=a_t\times E_{ijt}$$

(2)

where a_t is the correction coefficient of a basic equivalent factor of the ecosystem service value in year t; G_t′, G_t refer to the average unit yield of grain in Hubei Province and China in the year t, respectively (kg/hm²); W_t′, W_t refer to the annual average precipitation of Hubei Province and China in the year t, respectively (mm); E′_ijt, E_ijt are the equivalent factors of the ecological service function of a class I ecosystem and a class J ecosystem in Hubei Province and China in year t, respectively; where i = 1, 2, …, 6, followed by paddy fields, dry land, broad-leaved forests, meadows, water systems and bare land; and where j = 1, 2, …, 11, followed by food production, raw material production, water supply, gas regulation, climate regulation, environmental purification, hydrological regulation, soil conservation, nutrient cycle maintenance, biodiversity and aesthetic landscape.

(2)

Value correction of a standard unit ESV equivalence factor

Xie et al. [48] defined a standard unit ESV basis equivalent factor as the economic value of the annual natural grain production of farmland, with the average yield per hectare in China, and it is expressed as the net profit of the grain production of the farmland ecosystem per unit area [46]. This study evaluates the grain yield value of the farmland ecosystem in Hubei Province from 2010 to 2017 based on the three main grain products (i.e., rice, wheat and corn). The formula is as follows:

$$V_t=S_{rt}\times P_{rt}+S_{ct}\times P_{ct}+S_{wt}\times P_{wt}$$

(3)

where V_t refers to the ESV of one standard equivalent factor in year t of Hubei Province (USD/hm²); SRT, SCT and SWT, respectively, represent the percentage (%) of the sown area of rice, corn and wheat in the total sown area of the three crops in Hubei Province in the year t; and PRT, PCT and PWT are the average net profit per unit area of rice, corn and wheat in Hubei Province in the year t, respectively (USD/hm²).

(3)

Correction of the coefficient of ESV per unit area

The development of society and the economy lead to differences in ESV. The coefficient of social development refers to the relative level of people’s willingness to pay for ecological value under different levels of social development [49,50]. Therefore, based on previous studies [49,50], according to the urbanization and economic development level of Hubei Province and China from 2010 to 2017, this study constructs the coefficient of willingness to pay and the coefficient of the ability to pay. This paper modifies the coefficient of ESV in Hubei Province from 2010 to 2017. The formulas are as follows:

$$l_t=(H_t\times L)/(1+e^{-\left(1/E_{nt}-3\right)})+\left(h_t\times L\right)/(1+e^{-\left(1/E_{nrt}-3\right)})$$

(4)

$$T_t=l_t^{\prime }/l_t$$

(5)

$$P_t=GD{P}_t^{\prime }/GD{P}_{t }$$

(6)

$$V{C}_{ijt}=T_t\times P_t\times V_t\times E_{ijt}^{\prime }$$

(7)

where l_t is the coefficient of the social development level in year t; L is the value of the social development coefficient in the ideal stage, which is usually is one; H_t and h_t are the proportion of the urban and rural population in the total population in year t (%); E_nt and E_nrt are urban and rural Engel coefficients in year t, respectively; T_t is the coefficient of the regional willingness to pay in year t; l_t′ and l_t are the coefficients of social development in Hubei Province and China in the year t, respectively; P_t is the coefficient of the regional payment capacity in year t; GDP_t′ and GDP_t are the per capita GDP of Hubei Province and China in the year t, respectively (USD); and VC_ijt refers to the coefficient per unit area of type i and type j of the ESV function of Hubei Province in year t (USD/hm²).

3.3.3. Evaluation of Gains and Losses of ESV of Land Consolidation Projects

According to existing studies [35,36,37,38,39], the gains and losses of the ESV evaluation model of land consolidation projects in the study area is set as:

$$ES{V}_{before}={{\displaystyle \sum }}^{ }{{\displaystyle \sum }}^{ }{A}_i\times V{C}_{ij}$$

(8)

$$ES{V}_{after}={{\displaystyle \sum }}^{ }{{\displaystyle \sum }}^{ }{A}_i^{\prime }\times V{C}_{ij}^{\prime }$$

(9)

$$ES{V}_{pl}=ES{V}_{after}-ES{V}_{before}$$

(10)

where ESV_before and ESV_after are the total amounts of ESV before and after land consolidation in the project area (USD); A_i and A_i′ are the area of type I land use type before and after consolidation (hm²); i = 1, 2, …9, followed by paddy fields, dry land, garden land, forest land, pits and ponds, ditches, wasteland, rural roads and others; VC_ij and VC′_ij represent the value coefficient of the ecosystem service functions of type i land use type and type j before and after land consolidation, respectively; and ESV_pl represents the gains and losses of ESV in the project area (USD).

Due to the differences in construction scale, it is impossible to accurately measure the difference between the total gains and losses of the ESV of land consolidation projects with a variety of properties and geomorphic types only by the rate of gains and losses. According to the principle of comparability, this study employs the gains and losses of ESV to characterize the differences, and its evaluation formula is as follows:

$$ES{V}_{plr}=\left(ES{V}_{pl}/ES{V}_{before}\right)\times 100$$

(11)

where ESV_plr represents the rate of gains and losses (%).

Moreover, since the supply service value of the land consolidation area before consolidation is zero, the method of the rate of gains and losses cannot be used to compare the differences of the ESV functions of different landform projects. Therefore, according to the principle of comparability, this study employs the gains and losses of the ESV of the construction scale per unit area to characterize the differences, and its evaluation formula is as follows:

$$ES{V}_{pua}=\left(ES{V}_{pl}/S\right)$$

(12)

where ESV_pua represents the gains and losses of the ESV of the construction scale per unit area (USD/hm²), and S represents the construction scale of the project (hm²).

4. Results and Analysis

4.1. Source of ESV and the Change Patterns of the Total Amount in the Project Area

4.1.1. Land Consolidation Areas

The total amount and sources of ESV in the project area before and after land consolidation are shown in

Table 3. Changes in the total amount of ESV before and after consolidation Unit: ×10³ USD.

Time	Land Use Type	Plains				Mountains				Hills
		X11	X12	X13		X21	X22	X23		X31	X32	X33
Before consolidation	Paddy fields	0.00	0.00	0.00		0.00	0.00	0.00		0.00	0.00	0.00
	Dry land	0.00	0.00	0.00		0.00	0.00	0.00		0.00	0.00	0.00
	Gardens	0.00	0.00	0.00		0.00	0.00	0.00		0.00	0.00	0.00
	Woodland	0.00	0.00	0.00		0.00	0.00	0.00		0.00	0.00	0.00
	Pits	0.00	0.00	0.00		0.00	0.00	0.00		0.00	54.42	0.00
	Ditches	29.94	2.79	11.01		3.90	1.64	0.99		14.54	13.18	8.94
	Barren grassland	0.00	0.00	0.00		0.00	0.00	0.00		0.00	0.00	0.00
	Rural roads	0.00	0.00	0.19		0.18	0.08	0.02		2.68	0.49	0.15
	Other land	18.43	4.47	22.58		6.71	5.48	2.71		37.28	21.23	6.14
	Total	48.36	7.26	33.78		10.79	7.20	3.72		54.50	89.32	15.23
After consolidation	Paddy fields	38.42	22.49	287.93		0.00	25.93	24.63		292.97	126.17	33.74
	Dry land	38.84	3.40	0.00		58.27	23.48	0.00		48.30	46.93	23.70
	Gardens	0.00	0.00	0.00		0.00	0.00	0.00		0.00	2.14	0.00
	Woodland	0.00	0.00	0.00		0.00	0.00	0.00		0.00	26.31	0.00
	Pits	0.00	0.00	0.00		0.00	0.00	0.00		0.00	0.00	0.00
	Ditches	2.45	0.76	1.46		2.39	1.30	0.50		7.37	9.22	1.78
	Barren grassland	0.00	0.00	0.00		0.00	0.00	0.00		0.00	0.00	0.00
	Rural roads	0.31	0.05	0.60		0.19	0.05	0.01		1.38	0.35	0.04
	Other land	0.00	0.00	0.18		0.00	0.06	0.00		0.00	0.70	0.00
	Total	80.03	26.70	290.17		60.84	50.81	25.14		350.01	211.82	59.26
Gains and losses ratio/%		65.47	267.86	758.89		463.72	606.12	575.69		542.20	137.14	289.17

. Overall, after consolidation, the total amount of ESV in each project area increased, with an average growth rate of 412%, of which the mountains were the highest (549%), the plains were second (364%, and the hills were the lowest (323%). The changes in ESV sources in the project area before and after land consolidation led to this situation. Firstly, the types of ecological land increased from an average of 2.8 to 4.2. Secondly, there were changes in the dominant type of ecological land. Before consolidation, it mainly came from other lands and ditches, whereas after consolidation, it mainly came from paddy fields or dry land. Since the ESV coefficient per unit area of paddy fields and drylands is much higher than that of other lands and ditches, the total amount of ESV in the project area increased significantly after the consolidation of the disaster-damaged cultivated lands or ditches into cultivated lands (paddy fields and dry land). The above analysis shows that land consolidation can effectively improve land use efficiency and regional ESV, which is consistent with the theoretical analysis.

With respect to construction scale, the growth rate of ESV in plains, mountains and hills is X₁₃ > X₁₂ > X₁₁, X₂₂ > X₂₃ > X₂₁, and X₃₁ > X₃₃ > X₃₂, respectively, which indicates that the growth rate of ESV in the land consolidation project area decreases with the expansion of the project construction scale. It can be considered that the project construction scale is a factor affecting the ESV in the implementation of land consolidation projects. Under the same conditions of construction scale, the promotion of ESV by different landforms is as follows: the plains are the largest, the mountains are the second largest and the hills are the smallest.

4.1.2. Land Development Areas

It can be seen from

Table 4. Changes in the total amount of ESV before and after development. Unit: ×10⁵ USD.

Time	Land Use Type	Plains				Mountains				Hills
		Y11	Y12	Y13		Y21	Y22	Y23		Y31	Y32	Y33
Beforedevelopment	Paddy fields	35.89	13.15	6.83		1.29	0.00	0.00		0.00	0.00	2.05
	Dry land	66.89	37.40	1.64		20.09	16.01	1.53		13.61	6.35	4.06
	Gardens	0.00	0.00	0.00		0.00	0.00	0.00		0.00	0.00	1.52
	Woodland	0.00	0.00	28.69		6.96	16.77	54.09		0.00	17.30	14.07
	Pits	79.01	100.53	56.33		0.00	0.00	0.00		0.00	74.44	0.00
	Ditches	8.12	2.86	0.17		0.39	0.13	0.00		0.89	0.00	0.17
	Barren grassland	0.00	0.84	3.11		6.32	8.24	0.61		26.44	12.26	2.23
	Rural roads	0.14	0.04	0.01		0.05	0.02	0.00		0.06	0.00	0.01
	Other land	0.18	0.04	0.00		0.20	0.15	0.01		0.05	0.02	0.00
	Total	190.23	154.86	96.78		35.31	41.34	56.25		41.04	110.37	24.11
After development	Paddy fields	21.16	8.21	5.08		0.65	0.00	0.00		0.00	0.00	1.15
	Dry land	32.81	23.66	5.12		10.97	13.77	2.76		16.86	9.85	4.32
	Gardens	0.00	0.00	0.00		0.00	0.00	0.00		0.00	0.00	0.39
	Woodland	0.00	0.00	1.30		2.29	0.00	19.50		0.00	0.00	2.10
	Pits	3.38	49.10	35.96		0.00	0.00	0.00		0.00	41.69	0.00
	Ditches	3.62	3.00	0.15		0.23	0.30	0.06		1.98	0.00	0.12
	Barren grassland	0.00	0.00	0.00		1.13	0.00	0.04		0.00	0.00	0.15
	Rural roads	0.05	2.13	0.02		0.03	1.36	0.45		3.85	0.00	0.01
	Other land	0.06	1.39	0.00		0.12	5.30	0.81		1.99	0.36	0.01
	Total	61.08	87.49	47.63		15.42	20.73	23.62		24.67	51.90	8.26
Gains and losses ratio/%		−67.89	−43.50	−50.79		−56.34	−49.84	−58.01		−39.89	−52.97	−65.74

that the total amount of ESV in each project area decreased compared with that before land development, and the average loss rate is 53.89%. There are several reasons. First, the source of ESV in the project area decreased from 6.2 to 5.6. Second, there was a change in the dominant type, from the pits, ponds and forest land before development to the paddy fields and dry land after development, and the ESV coefficient per unit area of pits, ponds and forest land is much higher than that of paddy fields or dry land. The development of pits, ponds and forest land into paddy fields or dry land could not account for the loss of ESV, resulting in the loss of the total amount of ESV.

For different landforms, the average loss rates of the total ESV of projects in plains, mountains and hills were 54.06%, 54.73% and 52.86%, respectively. The main sources of loss were from pits and ponds, forest land and wasteland. The ESV coefficient per unit area of pits, ponds, forest land and wasteland is: pits and ponds > forest land > wasteland, and thus, the loss rates of the three vary a lot.

With respect to construction scale, the ESV loss rates in plains, mountains and hills were Y₁₁ > Y₁₃ > Y₁₂, Y₂₃ > Y₂₁ > Y₂₂ and Y₃₃ > Y₃₂ > Y₃₁, respectively. Among the typical research objects selected in plains and mountains, when the project construction scale was small or large, the loss rate of ESV was large after land development. In hills, the ESV loss rate decreased with the expansion of construction scale. Moreover, under the same construction scale, after the implementation of land development in plains and hills, the loss of ESV was more serious than that in mountains. The performance is as follows: the loss in the plains was the largest, followed by hills, and the smallest was in the mountains.

4.1.3. Land Arrangement Area

As can be seen from

Table 5. Changes in the total amount of ESV before and after arrangement. Unit: ×10⁵ USD.

Time	Land Use Type	Plains				Mountains				Hills
		Z11	Z12	Z13		Z21	Z22	Z23		Z31	Z32	Z33
Before arrangement	Paddy fields	14.35	15.68	6.76		0.00	0.00	0.00		66.97	37.65	0.00
	Dry land	18.69	27.23	7.80		16.88	5.81	2.38		16.18	23.20	3.67
	Gardens	0.00	0.00	0.00		0.00	21.88	8.75		0.00	0.00	0.00
	Woodland	0.00	0.00	2.58		0.00	19.62	0.00		0.00	0.00	42.89
	Pits	1707.77	4.32	304.10		7.36	0.00	0.00		568.03	71.47	0.00
	Ditches	0.00	3.16	1.75		0.74	0.26	0.00		2.19	2.13	0.17
	Barren grassland	2.85	0.40	0.00		1.79	0.00	0.00		5.80	1.69	1.74
	Rural roads	0.00	0.12	0.03		0.04	0.03	0.00		0.07	0.09	0.01
	Other land	0.08	0.16	0.02		0.00	0.05	0.00		0.36	0.25	0.03
	Total	1743.74	51.08	323.05		26.81	47.64	11.12		659.60	136.47	48.50
After arrangement	Paddy fields	7.98	8.19	3.35		0.00	0.00	0.00		41.46	15.73	0.00
	Dry land	9.92	14.20	4.38		6.97	3.13	1.33		10.63	10.13	5.75
	Gardens	0.00	0.00	0.00		0.00	10.40	3.72		0.00	0.00	0.00
	Woodland	0.00	0.00	1.53		0.00	9.45	0.00		0.00	0.00	0.00
	Pits	801.30	0.00	137.16		3.19	0.00	0.00		333.62	30.27	0.00
	Ditches	0.00	1.30	0.79		0.31	0.13	0.00		4.05	0.69	0.12
	Barren grassland	1.06	0.00	0.00		0.61	0.00	0.00		2.53	0.00	0.00
	Rural roads	0.00	0.06	0.02		0.02	0.01	0.00		3.47	0.04	0.01
	Other land	0.03	0.06	0.00		0.00	0.02	0.00		12.27	0.10	0.02
	Total	820.28	23.82	147.23		11.11	23.14	5.06		408.03	56.96	5.90
Gains and losses ratio/%		−52.96	−53.37	−54.43		−58.55	−51.42	−54.55		−38.14	−58.26	−87.83

, compared with that before the land arrangement, the total amount of ESV in each project area was lost, with an average loss rate of 56.61%, of which the hills were the highest (61.41%), the mountains were the second highest (54.84%) and the plains were the lowest (53.58%). The reasons are as follows: first, the types of ecological land in the project area after arrangement were reduced from an average of 5.6 to 5.3. The second reason is that there were changes in the main ecological land types and areas. The loss of ESV in plains and hills was mainly caused by reductions in pit and pond areas. In mountains, the total amount of ESV decreased mainly due to reductions in garden areas.

From the perspective of construction scale, the ESV loss rates in plains, mountains and hills were as follows: Z₁₃ > Z₁₂ > Z₁₁, Z₂₁ > Z₂₃ > Z₂₂, Z₃₃ > Z₃₂ > Z₃₁. Among the typical research objects that were selected in plains and hills, the loss rate of ESV decreased with the expansion of the construction scale. In mountains, when the project construction scale was small or large, the land arrangement presented the characteristics of a high level of ESV loss rate. Under the same construction scale, the ESV loss was the largest in plains, the second largest in hills and the smallest in mountains.

4.1.4. Comparison of the Total Gains and Losses of ESV in Different Project Areas of the Same Landform

Compared with that before land consolidation, the total amount of ESV in the land consolidation project area increased under the same geomorphic conditions, mainly due to increases in cultivated land (including paddy fields and dry land). The total amount of ESV in the land development and arrangement project area was lost, and the patterns of the rate of gains and losses generally show that the land development project was lower than the land arrangement, which was mainly caused by different sources of ESV loss. The former came from forest land, and the latter came from pits and ponds. Since the ESV coefficient per unit area of pits and ponds was much higher than that of forest land, the total loss rate of ESV in land arrangement areas was slightly higher than that in land development areas.

4.2. Change Patterns of ESV Composition in the Project Area

Existing research results [4] demonstrate that ecosystem services in the project area are divided into 4 categories and 11 subcategories, including supply services (food production, raw material production and water resources supply), regulation services (gas regulation, climate regulation, environmental purification and hydrological regulation), support services (soil conservation, nutrient cycle and biodiversity maintenance) and cultural services (aesthetic landscape). The change patterns of the service function value of each ecosystem before and after land consolidation projects with different properties and landforms are as follows:

4.2.1. Supply Service

As shown in Figure 3, after land consolidation, the value of the supply service function of land consolidation projects with different natures and landforms shows a decreasing trend, and the average loss of construction scale per unit area is 399 USD/hm². Under similar conditions, the trend of construction scale loss per unit area in different geomorphic areas is shown. The plains are the largest, the mountains are the second largest and the hills are the smallest. This is mainly caused by different sources of ESV loss in different geomorphic areas. The plains are dominated by pits and ponds, the mountains are dominated by woodland and the hills are dominated by wasteland; the value coefficients of the supply service per unit area of the three is the following: pits and ponds > woodland > wasteland. Under the same landform, the tendency of ESV loss per unit area of the construction scale of land consolidation projects with numerous properties is the following: land arrangement > land reclamation > land development. On the one hand, the supply service value coefficient of pits and ponds is much higher than that of other land types, and the object of the land arrangement is mainly pits and ponds. Therefore, the loss of regional supply service value is serious. On the other hand, the functional value coefficient of the water resource supply of paddy fields is negative. Although the area of paddy fields in the project area increases significantly after land consolidation, the supply service value decreases significantly. The main object of the land development project is forest land. Due to its importance to regional ecosystem regulation, if it is not necessary, it is retained as much as possible, and thus the loss of supply service value can be reduced.

4.2.2. Regulation Service

As can be seen from Figure 4, compared with that before land consolidation, the value of the regulation service function of land consolidation projects increased in the land consolidation area, and the average increase in construction scale per unit area was 1400 USD/hm², which was mostly due to increases in cultivated land (paddy fields and dry land). In the land development and consolidation areas, the average loss of construction scale per unit area was 3197 USD/hm² and 7379 USD/hm², respectively, which was caused by reductions in forest land as well as pit and pond areas. Additionally, the increase in construction scale per unit area in land consolidation area is as follows: plains > hills > mountains. The trend of construction scale loss per unit area in land development and arrangement areas is as follows: plains > hills > mountains. Under the same landform conditions, the average loss of construction scale per unit area of projects with different properties is as follows: in plains and hills, land development < land arrangement, whereas in mountains, land development > land arrangement.

4.2.3. Support Service

As can be seen from Figure 5, compared with that before land consolidation, the value of the support service function of land consolidation projects increased in the land consolidation area, and the average increase in construction scale per unit area was 175 USD/hm², which was mainly due to increases in cultivated land (paddy fields and dry land). In the land development and arrangement areas, the average loss of construction scale per unit area was 650 USD/hm² and 647 USD/hm², respectively, which was caused by reductions in forest land as well as pit and pond areas. Additionally, the increase in construction scale per unit area in land consolidation area is as follows: mountains > hills > plains. The trend of construction scale loss per unit area in land development and arrangement areas is as follows: mountains > hills > plains. Under the same landform conditions, the average loss of construction scale per unit area of projects with various properties is as follows: in plains and hills, land development < land arrangement, whereas in mountains, land development > land arrangement.

4.2.4. Cultural Service

As shown in Figure 6, compared with that before land consolidation, the value of the cultural service function of land consolidation projects increased in the land consolidation area, and the average increase in construction scale per unit area was 20 USD/hm², which was mainly due to changes in landscape pattern. In the land development and arrangement areas, the average loss of construction scale per unit area was 136 USD/hm² and 146 USD/hm², respectively, which was caused by reductions in land use diversity. Additionally, the increase in construction scale per unit area in land consolidation area is as follows: plains > hills > mountains. The trend of construction scale loss per unit area in land development and arrangement areas is as follows: mountains > hills > plains. Under the same landform conditions, the average loss of construction scale per unit area of projects with various properties is as follows: in plains and hills, land development < land arrangement, whereas in mountains, land development > land arrangement.

4.2.5. Change in the Value Contribution Rate of Different Service Functions

It can be seen from Figure 7 that the contribution rate of different service function values to the total ESV in the project area before and after land consolidation is as follows: regulation service > support service > supply service > cultural service. Compared with that before land consolidation, the contribution rate of the supply service value shows a downward trend in the land consolidation area, which was mainly due to increases in the large areas of paddy fields after consolidation (the water resource supply function value of paddy fields is negative), which led to decreases in the supply service value. There was an increasing trend in land development and arrangement areas, mainly due to increases in paddy fields or dry land areas. The value contribution rate of regulation and support services shows an increasing trend in land consolidation areas, mainly due to increases in paddy fields or drylands. There was a decreasing trend in land development and consolidation areas, mainly due to reductions in pits and ponds or forest land areas. The contribution rate of the cultural service function value in different project areas shows a downward trend, which was primarily due to the regulation of pits, ponds, woodlands and others into cultivated land, resulting in a relatively single farmland ecosystem and a decline in regional landscape heterogeneity.

4.2.6. Changes in Gain and Loss Composition of ESV in the Project Area

It can be seen from Table 3, Table 4 and Table 5 that the total amount of ESV in the land consolidation project area increased. The total amount of ESV in the land development and arrangement project area decreased. As seen in Figure 8, the added value of the total ESV in the land consolidation area mainly came from the regulation service, and its added value accounts for an average proportion of 128% of the added value of the total ESV. Although the support and cultural service increased, the proportion was relatively small. The value of the supply service function not only did not promote the increase in ESV, but it further hindered the improvement of ESV. From the perspective of land development and arrangement project area, the main source of their ESV loss was the regulation service, and the loss value accounts for an average of 73% and 79% of the total loss value, respectively. It can be considered that, in order to achieve the goal of increasing cultivated land, land regulation has the behavior of production for ecology to destroy the ecological environment.

5. Discussion

Compared with existing studies [35,36,37,38,39], it can be seen that there are obvious differences in the gains and losses of ESV and in the sources of land consolidation projects with different research, geomorphic types and construction scales. In parallel, various research methods can lead to different results [47]. This study employs the modified equivalent factor method to analyze the gains and losses of the ESV of different land consolidation projects under different landforms, which accounts for the deficiency of existing research in case selection.

(1)

Land consolidation projects of different natures have different impacts on regional ESV. This study shows that that land consolidation projects can effectively enhance regional ESV, which is consistent with the findings of Li et al. [42]. Land development and arrangement projects can lead to losses of regional ESV, which is consistent with the findings of Liu et al. [43] and Dang et al. [44]. The above mechanisms are closely related to the focus of land consolidation projects. Land consolidation focuses on “turning waste into treasure” and reclaiming disaster-damaged land to make it usable. Land development focuses on “open source”, mostly developing unused land in the project area into cultivated land, thus increasing the amount of cultivated land in the project area. Land arrangement focuses on “throttling”, mainly through internal potential tapping, and it comprehensively renovates the “fields, water, roads, forests and villages” in the project area, thus increasing the area of cultivated land and promoting the ecological environment. The above findings are a valid complement to the findings of Gu [35] and Zhang [38] on reductions in the ESV in all land consolidation projects in different types of zones. Therefore, it can be considered that the different features are a significant factor that affects the gains and losses of ESV in the implementation of land consolidation. In order to improve the ecological service function of the project area, we must choose appropriate methods to achieve land consolidation projects according to the local conditions and regional land use characteristics.

(2)

The scale of construction is an important factor affecting the profit and loss of ESV in the land consolidation area. This paper found that the growth rate of ESV in the land consolidation project area showed a decreasing trend with the expansion of the project construction scale. The loss rate of ESV in land development and arrangement projects in different landscape areas showed significant differences with the construction scale, which is consistent with the findings of Guo et al. [36] and Zhao et al. [20] on the construction scale of land consolidation projects as an important factor affecting the gains and losses of ESV in the land consolidation area. Therefore, an appropriate construction scale should be adopted in the feasibility study and planning stage to improve the ecological environment of the project area.

(3)

Geomorphic conditions are an important factor affecting ESV gains and losses in land consolidation areas. This study found that, under similar features and construction scales, the growth rate of ESV in land consolidation areas is as follows: plains > mountains > hills. The ESV loss rate of land development and arrangement areas is as follows: plains > hills > mountains, which is consistent with the research results of Jiang et al. [37] and Yu et al. [39]. Due to terrain factors, land consolidation in plains and hills focuses on the adjustment of the area of various ecological functional land types. However, in mountains, land consolidation not only adjusts the number of ecological functional land types, but it also improves the ecological environment elements in the project area with adopted projects and technologies. In parallel, the mechanism of the losses of ESV in various geomorphic areas in this paper is inconsistent with the findings of Gu [35] and Zhang [38], because the latter only chooses one typical case of each geomorphic type project. This paper considers the characteristics of construction scale and project features, and thus the results are more representative.

(4)

Land use change is a determinant of the gains and losses of ESV in land consolidation areas. The empirical results show that increases or decreases in ecological land use types such as ponds and woodlands directly affect the regional gains or losses of ESV, which is consistent with the findings of Guo et al. [36], Gu [35] and Zhang [38]. The main reason is that the ecological service value coefficients of different land use types are obviously different, and the unit surface ecological service value coefficients of ponds are 7 times higher than those of forest land, 30 times higher than those of barren land, 46 times higher than those of dry land and 49 times higher than those of paddy land. Therefore, the protection of ponds and forest land should be strengthened during the implementation of land consolidation and should be preserved as much as possible if not necessary.

Certainly, this study has the following shortcomings:

(1)

The evaluation method of this study needs to be further optimized. Since the equivalent correction method only evaluates ESV according to the changes in ecosystem area, biomass and rainfall, which ignores the implicit value of land consolidation through improving the landscape pattern and attracting more tourists, it underestimates the ESV. For example, the ESV evaluated by the single service evaluation method is higher than that evaluated by the equivalent factor method [47]. Therefore, more action should be taken to further optimize the ESV evaluation method of land consolidation projects to obtain a more accurate mechanism.

(2)

The spatio-temporal scale of this paper needs to be improved. Guo et al. [31] and Sun et al. [33] showed that the implementation of land consolidation projects has a relatively obvious negative impact on regional ecological quality. However, with the passage of time after implementation, the negative impact diminishes and gradually presents a positive impact, and the ecological environment quality of the project area continues to improve. This study only statically assesses the ESV of the project area before and after consolidation and does not consider continuous changes in ESV in the project area after the implementation of land consolidation. A long-term and dynamic study of the interannual change trend of the ecological benefits of land remediation will be our next research focus. On a spatial scale, Sun et al. [33] and Yan et al. [51] showed that there is significant spatial heterogeneity in the impact of land consolidation on the regional ecological environment. In this paper, only the ESV within the land consolidation project area was assessed, and the characteristics of ESV changes in the adjacent areas of the land consolidation project were not considered. Therefore, the evaluation unit can be expanded to the land consolidation project area and the surrounding areas in the future.

6. Conclusions and Policy Recommendations

6.1. Conclusions

This paper selects typical land consolidation, development, and arrangement projects as the research object from the three land consolidation types of plains, mountains and hills in Hubei Province, and it studies the regional gain and loss patterns of the ESV of land consolidation projects with different properties and geomorphic types. The following conclusions can be drawn:

Compared with that before land consolidation,

(1)

The gains and losses of the ESV of land consolidation projects with different features and landforms vary a lot. The total amount of ESV in the land consolidation project area increased, with an average increase of 412%. Land development and arrangement project areas decreased, with an average decrease of 53.89% and 56.61%, respectively. Under the same feature, the growth rate of the land consolidation area was as follows: hills < plains < mountains. The loss rates of the land development and consolidation areas were as follows: mountains > plains > hills and hills > mountains > plains. Under the same landform, the loss rates of the land development projects were lower than those of land arrangement projects.

(2)

The total amount of ESV supplying service functions in land consolidation project areas with different properties and landforms shows a decreasing trend. The total amount of ESV regulating services, support services and cultural services shows an increasing trend in land consolidation areas and a decreasing tendency in land development and arrangement areas, and the gains and losses vary in different geomorphic areas.

(3)

There is value in the transformation process of “ecology for production” in land consolidation projects. The contribution rate of supply service value to the total amount of ESV decreased in the land consolidation areas and increased in the development and arrangement areas. The contribution rate of regulation and support service values increased in land consolidation areas and decreased in development and arrangement areas. The contribution rate of cultural service value showed a downward trend in different land consolidation project areas.

6.2. Policy Recommendations

Based on the above conclusions, this paper suggests the following recommendations:

(1)

Optimize the structural arrangement of regional land remediation projects with different properties. As the consolidation object of land consolidations project is disaster-damaged land, which is uncontrollable, it should be arranged according to the situation of regional disaster-damaged land. The ESV loss rate of land development projects is relatively high in mountains and plains and low in hills. Therefore, we can reduce or even strictly control the arrangement of land development projects in mountains or plains, and we can strengthen investment in land development in hills, thus accounting for continuous reductions in cultivated land in the process of urbanization. In parallel, the ESV loss rates of land arrangement projects in mountains and hills are significantly higher than those for plains. Therefore, we can carry out more land arrangement projects in plains, and we can strengthen the comprehensive treatment of regional fields, water, roads, forests and villages. Additionally, we can improve regional land use efficiency, regional production, and living and ecological environment through internal potential tapping.

(2)

Strengthen the ecological and global transformation of land consolidation. The goal of traditional land consolidation is mostly to increase newly cultivated land area, and it ignores some comprehensive objectives, such as regional economy and ecology. Most of the consolidation methods are designed to convert other land types into cultivated land, such as pits and ponds, forest land or wasteland, resulting in a serious loss of regional ESV. However, due to the continuous advancement of urbanization, land consolidation based on the program Plus and Minus Hook between Urban and Rural Construction Land is an important means to account for the occupation of cultivated land by construction land and thus to protect food security. Investing in land consolidation needs to be increased, and the ecological and comprehensive transformation of land consolidation must be carried out. First of all, we must strengthen the protection of ecological land types (e.g., pits and ponds) in the implementation of land consolidation, adopting eco-friendly materials and implementing the ecological consolidation mode. Secondly, we must establish a multi-objective and multi-pattern comprehensive objective system of land consolidation. With the continuous implementation of ecological civilization construction and rural revitalization, increases in cultivated land cannot meet people’s requirements for production, daily life and ecology. In this context, the Chinese government has proposed a comprehensive land consolidation framework, which can bring good benefits to newly cultivated land and can achieve a good comprehensive effect for the combination of production, living and ecological benefits, providing a direction for future land consolidation.

(3)

Accelerate the establishment of a reasonable ecological compensation mechanism. The main goal of land consolidation is to increase the area of cultivated land and to improve the quality of cultivated land. There is value in the transformation process of "ecology for production". Although some scholars and government officials have paid some attention to the ecological environment damage caused by land consolidation, there is a lack of a reasonable ecological compensation mechanism to account for the loss of ESV caused by land consolidation. More measures can be taken to make organizations responsible for the destruction of the ecological environment of land consolidation, and the regional ecological environment can be better protected through the construction of ecological compensation mechanisms, such as nature reserves and environmental evaluations.