China’s Key Forestry Ecological Development Programs: Implementation, Environmental Impact and Challenges

Community-based assessment of the dynamics of urban landscape characteristics and ecosystem services in the rainforest and guinea savanna ecoregions of Nigeria

Understanding the dynamics of urban landscapes and their impacts on ecological well-being is crucial for developing sustainable urban management strategies in times of rapid urbanisation. This study assesses the nature and drivers of the changing urban landscape and ecosystem services in cities located in the rainforest (Akure and Owerri) and guinea savannah (Makurdi and Minna) of Nigeria using a combination of remote sensing and socioeconomic techniques. Landsat 8 datasets provided spatial patterns of the normalised difference vegetation index (NDVI) and normalised difference built-up index (NDBI). A household survey involving the administration of a semi-structured questionnaire to 1552 participants was conducted. Diminishing NDVI and increasing NDBI were observed due to the rising trend of urban expansion, corroborating the perception of over 54% of the respondents who noted a decline in landscape ecological health. Residential expansion, agricultural practices, transport and infrastructural development, and fuelwood production were recognised as the principal drivers of landscape changes. Climate variability/change reportedly makes a 28.5%-34.4% (Negelkerke R2) contribution to the changing status of natural landscapes in Akure and Makurdi as modelled by multinomial logistic regression, while population growth/in-migration and economic activities reportedly account for 19.9%-36.3% in Owerri and Minna. Consequently, ecosystem services were perceived to have declined in their potential to regulate air and water pollution, reduce soil erosion and flooding, and mitigate urban heat stress, with a corresponding reduction in access to social services. We recommend that urban residents be integrated into management policies geared towards effectively developing and enforcing urban planning regulations, promoting urban afforestation, and establishing sustainable waste management systems.

The past and future of ecosystem restoration in China

For decades, China has implemented restoration programs on a large scale, thanks to its capacity to set policy and mobilize funding resources. An understanding of China's restoration achievements and remaining challenges will help to guide future efforts to restore 30% of its diverse ecosystems under the Kunming-Montreal Global Biodiversity Framework. Here we summarize the major transitions in China's approach to ecosystem restoration since the 1970s, with a focus on the underlying motivations for restoration, approaches to ecosystem management, and financing mechanisms. Whereas China's restoration efforts were predominantly guided by the delivery of certain ecosystem functions and services in earlier decades, more recently it has come to emphasize the restoration of biodiversity and ecosystem integrity. Accordingly, the focal ecosystems, approaches, and financing mechanisms of restoration have also been considerably diversified. This evolution is largely guided by the accumulation of scientific evidence and past experiences. We highlight the key challenges facing China's restoration efforts and propose future directions to improve restoration effectiveness, with regard to goal setting, monitoring, stakeholder involvement, adaptive management, resilience under climate change, and financing.

Environmental and social impacts of carbon sequestration

Climate change requires major mitigation efforts, mainly emission reduction. Carbon sequestration and avoided deforestation are complementary mitigation strategies that can promote nature conservation and local development but may also have undesirable impacts. We reviewed 246 articles citing impacts, risks, or concerns from carbon projects, and 78 others related to this topic. Most of the impacts cited focus on biodiversity, especially in afforestation projects, and on social effects related to avoided deforestation projects. Concerns were raised about project effectiveness, the permanence of carbon stored, and leakage. Recommendations include accounting for uncertainty, assessing both mitigation and contribution to climate change, defining permanence, creating contingency plans, promoting local projects, proposing alternative livelihoods, ensuring a fair distribution of benefits, combining timber production and carbon sequestration, ensuring sustainable development and minimizing leakage. A holistic approach that combines carbon sequestration, nature conservation, and poverty alleviation must be applied. The potential occurrence of negative impacts does not invalidate carbon projects but makes it advisable to conduct proper environmental impact assessments, considering direct and indirect impacts, minimizing the negative effects while maximizing the positive ones, and weighing the trade-offs between them to guide decision-making. Public participation and transparency are essential. Integr Environ Assess Manag 2024;00:1-27. © 2024 SETAC.

Unraveling the enigma of NPP variation in Chinese vegetation ecosystems: The interplay of climate change and land use change

Global carbon emissions have exacerbated the greenhouse effect, exerting a profound impact on ecosystems worldwide. Gaining an understanding of the fluctuations in vegetation net primary productivity (NPP) is pivotal in the assessment of environmental quality, estimation of carbon source/sink potential, and facilitation of ecological restoration. Employing MODIS and meteorological data, we conducted a comprehensive analysis of NPP evolution in Chinese vegetation ecosystems (VESs), employing Theil-Sen median trend analysis and the Mann-Kendall test. Furthermore, utilizing scenario-based analysis, we quantitatively determined the respective contributions of climate change and land use change to NPP variations across various scales. The overall NPP exhibited a discernible upward trend from 2000 to 2020, with a growth rate of 5.83 gC·m-2·year-1. Forestland ecosystem (FES) displayed the highest rate of increase (9.40 gC·m-2·year-1), followed by cropland ecosystem (CES) (4.00 gC·m-2·year-1) and grassland ecosystem (GES) (3.40 gC·m-2·year-1). Geographically, NPP exhibited a spatial pattern characterized by elevated values in the southeast and diminished values in the northwest. In addition, climate change had elevated 76.39 % of CES NPP, 90.62 % of FES NPP, and 71.78 % of GES NPP. At the national level, climate change accounted for 83.14 % of the NPP changes, while land use change contributed 14.14 %. Notably, climate change emerged as the primary driving force behind NPP variations across all VEGs, with land use change exerting the most pronounced influence on CES. At the grid scale (2 km × 2 km), land use change played a substantial role in all VEGs, contributing 60.01 % in CES, 54.20 % in FES, and 55.61 % in GES of the NPP variations.

Knowledge exchange in the implementation of National Environmental Programmes (NEPs) in China: A complex picture

Knowledge is an intrinsic element of environmental management. Understanding what kinds of knowledge are needed and how to communicate them effectively is crucial for building environmental management capacity. Despite extensive research, knowledge and its exchange are commonly considered from the viewpoint of its creators and disseminators, rather than that of its recipients. This can lead to mismatches between supply of and demand for knowledge, and futile knowledge exchange that undermines the effectiveness of interventions. Research is needed that looks carefully at the contexts and consequences of such scenarios. Addressing this gap, we examine the implementation of National Environmental Programs (NEPs) in north-western China, drawing from interviews and questionnaires with scientists, grassroots implementers, and farmers and herders, to identify what and how knowledge has been exchanged and what their perspectives are about knowledge exchange with other actors. We ascertain the positive impacts of knowledge exchange during NEP implementation, as well as the consequences when it is lacking, by analysing the interfaces and interactions between actors, seeking explanation for successes and failures. We conclude that with changing socio-ecological systems, knowledge and its exchange also need to change accordingly, extending beyond the environmental domain to integrate local socioeconomic concerns. Such efforts are necessary to improve environmental management outcomes and advance sustainable development.

Multiscale ecosystem service synergies/trade-offs and their driving mechanisms in the Han River Basin, China: implications for watershed management

The synergies and trade-offs between ecosystem services (ESs) and their driving mechanisms are hot topics in ecology and geography research. In recent years, the Han River Basin (HRB) has been continuously impacted by high-intensity urban sprawl and the Middle Route of the South-to-North Water Diversion Project, which have posed severe threats to the ecology and regional stability along the route. It is thus critical to study the ES synergies/trade-offs and their driving mechanisms. Based on the InVEST model and the value coefficient method, four vital types of ESs in the HRB, i.e., carbon sequestration (CS), food supply (FS), net primary productivity (NPP), and water yield (WY), were evaluated at town, county, and sub-watershed scales. Then, the Pearson correlation analysis was adopted to quantify the interrelationship among different ESs. Finally, the ordinary least squares (OLS) and geographical detector model (GDM) were applied to reveal the driving mechanisms of the ES synergies/trade-offs. The results showed that (1) apart from NPP, which increased at a rate of 7.54 gC·m^-2·a^-1 during 2000-2018, the other three types of ESs in the HRB deteriorated, with WY almost halving. (2) While CS, FS, and WY tended to exhibit high synergistic relationships, NPP showed mostly trade-off relationships, and the evaluation scale did not affect those main relationships. (3) Precipitation is the strongest driving force for the ES synergies/trade-offs in the HRB, and natural factors are generally more influential than socioeconomic factors on the ES synergies/trade-offs. This study warns of the deteriorating ecological condition of the HRB and provides empirical evidence for the synergistic enhancement of regional ESs and the optimization of ecological management policies.

Carbon deficit checks in high resolution and compensation under regional inequity

Carbon compensation is an effective way of reducing carbon emissions. However, previous studies in this field have been limited and have not examined high-precision scientific carbon compensation under regional inequity. The present study examined initial carbon compensation in the grid and developed a new equitable carbon compensation model. Additionally, it modified the carbon compensation value for each province and analysed how land-use change affected carbon compensation. The results show that, after the modification, the entire carbon deficit reached 17.34 × 10⁸ t C in 2015, representing a decrease of 14% compared with the initial carbon deficit. The area with negative carbon deficit values accounted for 36% of the whole area, concentrated mainly in the south, southwest and northwest. Without modification, the initial carbon compensation reached 537 × 10⁸ USD, and only Yunnan, Sichuan and Hainan provinces being eligible to receive compensation. The final modified carbon compensation was approximately 20% of the initial values, and 11 provinces were eligible to obtain compensation. The other provinces responsible for paying the carbon compensation costs were typically concentrated in Central and Eastern China. Land-use changes in 2015 led to increases in the initial carbon compensation and modified carbon compensation of 3.74 × 10⁸ and 0.13 × 10⁸ USD, respectively. The per-unit land-use change caused greater increases in carbon emissions in China's big cities and the provinces in Central and East China. Some policies, such as macro-control by the central government, diversified forms and patterns of compensation, and auxiliary measures should be formulated/proposed.

Assessing the effects of China's Three-North Shelter Forest Program over 40 years

Forests provide vital ecosystem services such as soil and water conservation, climate regulation, and carbon storage. Large-scale afforestation programs are being attempted in many countries to improve environmental conditions in deteriorated or unfavorable locations. China's Three Northern Protected Forest Program (TNSFP), accounting for 42.40 % of China's total land area, is the world's largest afforestation program to date. The TNSFP has continued providing critical ecosystem services to humans over 73 years (1978-2050) with a total investment of CNY 93.3 billion. To facilitate understanding of the TNSFP's contribution, the effects of the TNSFP for last 43 years were comprehensively evaluated by using integrated review of structured literature, bibliometric analysis, and thematic analysis. We incorporated and expanded the direct ecosystem services evidence of the TNSFP from wind and sand control, soil erosion control and carbon sequestration to indirect economic benefits, e.g. increasing crop yield and promoting economic development. We found that over the past 40 years of TNSFP construction, wind and sand hazards and soil erosion in China's Three-North areas have been effectively controlled, and forest carbon sequestration, grain production and economic output have steadily increased. The ecosystem services provided by the TNSFP are highly consistent with the thrust of the UN Sustainable Development Goals, and the TNSFP has contributed to the realization of SDG2, SDG8, SDG13, and SDG15. Although achieving tremendous ecological, economic, and social benefits, the TNSFP still has knowledge gaps in its scientific basis. And the limited local engagement and insufficient investment highly hinder the TNSFP from playing its multiple functions. We suggest several urgent actions and directions to address these limitations. This review could help researchers gain insight into key areas of ecological restoration in the TNSFP, providing a reference for future research in the TNSFP construction in China and other regions of the world embarking on similar journeys.

Evolution Modes, Types, and Social-Ecological Drivers of Ecologically Critical Areas in the Sichuan–Yunnan Ecological Barrier in the Last 15 Years

The ecological barrier is a complex ecosystem that couples the human–nature relationship, and the ecologically critical area is an irreplaceable area with a special value in the ecosystem. Therefore, protecting the ecologically critical area is vital for maintaining and improving regional ecological security. Limited research has been conducted on the evolution of ecologically critical areas, and none of the studies have considered the spatiotemporal heterogeneity of the driving factors for different evolution modes and types. Therefore, this research adopts the ecologically critical index, landscape expansion index, and the random forest model to analyze the pattern, driving factors, and its spatial-temporal heterogeneity to the evolution modes and specific types of ecologically critical areas in the Sichuan–Yunnan ecological barrier area in the last 15 years. The results showed that: (1) the ecologically critical areas in the Sichuan–Yunnan ecological barrier have changed dramatically, with the area reduction being 61.06%. Additionally, the spatial distribution characteristics of the ecologically critical area from north to south include planar, point, and linear forms. (2) The evolution trend of the ecologically critical area is ‘degradation–expansion–degradation’. Spread is the predominant type of expansion mode, whereas atrophy is the predominant type of degradation mode, indicating that the evolution mainly occurs at the edge of the original ecologically critical areas. (3) In general, precipitation, area of forest, area of cropland, and GDP have contributed significantly to the evolution of ecologically critical areas. However, the same driving factor has different effects on the expansion and degradation of these areas. Expansion is driven by multiple factors at the same time but is mainly related to human activities and land use change, whereas for degradation, climate and policy are the main driving factors. The present research aimed to quantitatively identify the evolution modes and specific types of ecologically critical areas and explore the spatiotemporal heterogeneity of driving factors. The results can help decision-makers in formulating ecological protection policies according to local conditions and in maintaining and enhancing the regional ecological functions, thereby promoting the sustainable development of society-economy-ecology.

Soil Properties under Artificial Mixed Forests in the Desert-Yellow River Coastal Transition Zone, China

Mixed forests play a key role in the environmental restoration of desert ecosystems and in order to address the improvement of soil properties by different mixed vegetation types. We selected four typical mixed vegetation types (including: Populus alba var. pyramidalis × Caragana korshinskii, P. pyramidalis × Hedysarum mongdicum, P. pyramidalis × Hedysarum scoparium and Hedysarum scoparium × Salix cheilophila) that have been restored for 22 years and the moving sandy land in the transition zone between the desert and the Yellow River in northern China. We compared the differences in soil properties using a total of 45 soil samples from the 0–30 cm soil layer (10 cm units). We found that revegetation had a significant positive effect on fine particles, soil nutrients, soil bulk density (SBD), and soil fractal dimension (D) values. Soil D values under different types of vegetation range from 2.16 to 2.37. Soil nutrients and fractal dimension showed highly significant or stronger negative correlations with SBD and sand and highly significant or stronger positive correlations with clay and silt. The construction of P. pyramidalis × C. korshinskii improved the soil texture better than other vegetation restoration types. Compared to the mobile sandy land, organic carbon (SOC), available phosphorus (AP), available potassium (AK), alkaline hydrolysis nitrogen (AN), total nitrogen (TN), total potassium (TK), clay, and silt increased by 161%, 238%, 139%, 30%, 125%, 69%, 208%, and 441% respectively. As mentioned above, P. pyramidalis × C. korshinskii is a suitable type of mixed vegetation restoration for the area. In addition, establishing vegetation with high nitrogen fixation rates in desert ecosystems tolerant to drought and aeolian conditions is beneficial in reversing the trend of desertification. This research will suggest vegetation building strategies for controlling desertification.

Influence of Precipitation Characteristics and Vegetation on Runoff and Sediment: A Case on the Basin in the Three Gorges Reservoir Region

Sediment is the main carrier of pollutants in river channels. This study analyzed the distribution characteristics of precipitation, runoff, and sediment and their response characteristics in the Daning River basin. Based on daily precipitation (1979–2017), runoff (1989–2017), and sediment (1997–2017) time series, the Gini concentration index, precipitation concentration index (PCI), precipitation concentration degree (PCD), and precipitation concentration period were applied to assess the concentration characteristics of precipitation, runoff, and sediment on the daily, monthly, and seasonal scales. At each intensity level, precipitation was negatively correlated to the PCI and PCD. The normalized difference vegetation index (NDVI) values had strong negative correlations with rainy days with light precipitation (0.1–9.9 mm). The degrees of concentration were in the same order for the multiscale analysis: runoff < precipitation < sediment. Although the amount of daily precipitation of more than 25 mm displayed a significant increasing trend, suggesting an increased risk of flood and soil erosion, the significantly improved vegetation cover reduced the sediment-carrying capacity of the surface runoff, with significant decreases in the total amount and multiscale concentration degrees of sediment being observed. The results of the study provide a reference for the improvement of the potable water safety and ecological environment in the Three Gorges Reservoir region.

Unfolding the Success of Positive Human Interventions in Combating Land Degradation

A global challenge to sustainable development is land degradation, and to achieve land degradation neutrality, monitoring, mapping, and impact assessment of ongoing ecological restoration efforts is necessary. Here, we analyze the desertification process and role of restoration projects at a spatial and temporal scale in Mu Us Desert from 2001 to 2018. We used 17 years of data to (1) assess the vegetation trend including its significance and map land degradation based on Sustainable Development Goal Indicator 15.3.1 (2) address how vegetation activity has changed under the influence of restoration programs and climate change (3) estimate how successful are the positive human interventions to achieve Land degradation neutrality. Results showed an overall increasing vegetation trend (85.69% significant increasing) and a partial decreasing vegetation trend (1.33% significant decreasing) in Mu Us desert. Ecological restoration activities are found to be one of the key driving forces of vegetation restoration in the desert, however, limited impact of climatic factors on vegetation cover change was observed. Results revealed that 41.42% of total significant restoration is attributed to ecological restoration programs out of which 40.42% area has shown improvement in all three sub-indicators of land degradation.

Spatial and Temporal Variations of Habitat Quality and Its Response of Landscape Dynamic in the Three Gorges Reservoir Area, China

Habitat quality is an important indicator for assessing biodiversity and is critical to ecosystem processes. With urban development and construction in developing countries, habitat quality is increasingly influenced by landscape pattern changes. This has made habitat conservation to be an increasingly urgent issue. Despite the growing interest in this issue, studies that reveal the role of land use change in habitat degradation at multiple scales are still lacking. Therefore, we analyzed the spatial and temporal variations of habitat quality of the Three Gorges Reservoir area by the InVEST habitat quality model and demonstrated the responses of habitat quality to various landscape dynamics by correspondence analysis. The result showed that the habitat quality score of this area increased from 0.685 in 2000 to 0.739 in 2015 and presented a significant spatial heterogeneity. Habitat quality was significantly higher in the northeastern and southwestern parts of the reservoir area than in other regions. Meanwhile, habitat quality improved with altitude and slope, and increased for all altitude and slope zones. The habitat quality of >1000 m and >25° zone exceeds 0.8, while the habitat quality of <500 m and <15° zone is less than 0.6. Habitat quality significantly varied among landscape dynamics and was extremely sensitive to vegetation recovery and urban expansion. The vegetation restoration model of returning farmland to forest is difficult to sustain, so we suggest changing the vegetation recovery model to constructing complex vegetation community. This study helps us to better understand the effects of landscape pattern changes on habitat quality and can provide a scientific basis for formulating regional ecological conservation policies and sustainable use of land resources.