Emergy and Economic Evaluation of Seven Typical Agroforestry Planting Patterns in the Karst Region of Southwest China

A review of agroforestry ecosystem services and its enlightenment on the ecosystem improvement of rocky desertification control

Agroforestry (AF) has become an important strategy in reconciling the contradictory requirements of environmental protection and economic development in ecologically fragile areas, and whose multiple ecosystem services provide effective ways to promote the restoration of degraded ecosystems in the region. However, agroforestry ecosystem services (AFES) are usually constrained by their generative elements (vulnerability, structure, function, and ecological assets) and service management-both crucial for informed decision-making which enhances AFES supply capacity and AF sustainable management. Karst rocky desertification (KRD) is a typical case in an ecologically fragile area, and within the KRD region greatly relevant for promoting AFES as a strategy for restoring degraded regional ecosystems and for achieving sustainable development goals. In this study, a total of 164 publications related to AFES that met a set of inclusion criteria were obtained through the Scopus database using the literature review method of searching, appraisal, synthesis, and analysis. From the systematic literature review results, (i) we found that the number of relevant publications generally exhibited a year-on-year growth trend, with AFES generation elements being the most common topic (68.11 % of publications), and service management research being the second most common (31.89 % of publications); (ii) we summarised the main progress and landmark results of AFES generation elements and service management research and explored the relevant key scientific questions; and (iii) the above information enlightened the key improvement areas of KRD control ecosystem within three aspects: natural environment, agricultural development, and human-environment relationship. This study provides agroforestry practitioners and relevant decision-makers with information for improving and managing the supply capacity of AFES, and also presents important insights on the KRD control ecosystem to land degradation restoration technicians.

Progress on the Integrity Protection in the Natural World Heritage Site and Agroforestry Development in the Buffer Zone: An Implications for the World Heritage Karst

In the face of increasing development pressure, how to fulfill the obligations under the World Cultural and Natural Heritage Convention and maintain the integrity of the Natural World Heritage Site (NWHS) is a major problem to be solved at present. Agroforestry (AF) development in the buffer zone maintains the integrity of NWHS and promotes sustainable ecological and economic development in the buffer zone. Still, few studies on the knowledge system of integrity protection of NWHS and AF development in the buffer zone research have been conducted. To fill this gap, this study conducts a systematic literature review based on 128 related articles retrieved from the Web of Science (WoS) database and the China National Knowledge Infrastructure (CNKI) database. Firstly, quantitative studies were conducted to analyze the annual numbers, content and study regions of the published literature. Secondly, the main research progress and achievements of integrity protection of WNHS and AF development in the buffer zone are classified and summarized. On this basis, this paper proposed key scientific issues that remain to be addressed in future, as well as exploring the implications for the World Heritage (WH) karst. This study is a scientific reference for the balanced development of NWHS integrity protection and AF in the buffer zone.

Impact of Selected Environmental Factors on Variation in Leaf and Branch Traits on Endangered Karst Woody Plants of Southwest China

We explored the adaptability of endangered plants in degraded karst habitats through functional trait variation, using three endangered woody plants (E. cavaleriei, H. bodinieri and K. septentrionalis) in karst peak-cluster depression. We investigated the variation decomposition and correlation analysis of 13 branch and leaf functional traits using a mixed linear model, variance decomposition, Pearson’s correlation analysis, random forest regression, and generalized linear regression. The degree of variation in phosphorus concentration in the branches was the highest, while that in the carbon concentration in the leaves was the smallest. The variation in the carbon concentration in the branches and leaves, and the dry matter concentration in the leaves was mainly within species, while the variation in other functional traits was mainly between species. We found significant correlations among leaf traits, branch traits, and leaf–branch traits to different degrees; however, there were no significant correlations among branch traits in H. bodinieri. The significant correlations were higher in E. cavaleriei and K. septentrionalis than in H. bodinieri. Plant functional traits were influenced by soil and topographic factors, and the relationship between them varied by species. Our findings will enhance our understanding of the variation in leaf and branch traits in karst endangered plants and the adaptative strategies of endangered plants in degraded habitat, and will provide a scientific basis for vegetation conservation in the karst region of southwest China.

Structure and Stability of Agroforestry Ecosystems: Insights into the Improvement of Service Supply Capacity of Agroforestry Ecosystems under the Karst Rocky Desertification Control

Agroforestry provides essential ecosystem services; its structure and stability directly determine ecosystem function and service provision. Sustaining agroforestry ecosystem functions and services in the long term is necessary to meet the needs of people. This study conducted a literature search and statistical analysis based on WOS and CNKI literature databases. We reviewed 136 literature reports on studies of agroforestry ecosystem structure and stability. The landmark results are summarized in five aspects of agroforestry ecosystems: structure characteristics, structure optimization, structure design, stability research, and influence factors. On this basis, the key scientific issues that need to be solved are summarized, and their insights for improving the supply capacity of agroforestry ecosystem services under the rocky desertification control are discussed.

How can massive ecological restoration programs interplay with social-ecological systems? A review of research in the South China karst region

Exploring the cost-effective pathways for restoring ecosystems is a fundamental aspect for scientific communities and policy-makers aiming for a sustainable future. The South China karst region has experienced severe environmental degradation because of unsustainable management practices in this vulnerable social-ecological context. However, it has also become one of the most stunning areas following its remarkable vegetation recovery over recent decades as a result of large-scale ecological restoration programs. There is an extensive body of literature focusing on how ecological restoration programs have altered the degraded environment in this region. By searching and comparing the published peer-reviewed articles, we reviewed the studies related to the effects of ecological restoration programs from the point of view of ecological, socio-economic, and integrated social-ecological impacts, as well as influencing factors and restoration approaches. We found independent evidence to support that large-scale ecological restoration programs increased biomass and carbon sequestration since 2000 across this region. The farmers' livelihoods have spontaneously transited from agriculture into forestry or non-farming sectors without financial compensation or incentive schemes, which coincided with a positive correlation between the implementation of ecological restoration programs and poverty alleviation. However, due to a lack of clear "before and after" comparisons, many studies have indirectly determined the impacts of ecological restoration with non-negligible uncertainties. In addition, considering the critical interactions between belowground and aboveground processes in karst regions, special attention should be given to the selection of tree species and restoration measures according to different bedrock types. In the future, to better understand the impacts of ecological restoration on social-ecological systems, research could be advanced by considering data access, context-based analysis, measurement-targeted assessment, and cross-scale integration.

Agricultural Eco-Efficiency: Challenges and Progress

The research on agricultural eco-efficiency has become an important point to deeply understand the interaction between ecological and environmental conditions and socio-economic factors as well as realize the coordinated development of agricultural economic development and environmental protection. (1) Background: This paper attempts to provide scientific support for the healthy and stable development of the agricultural economy and the sustainable development of ecological agriculture. (2) Methods: From a comprehensive perspective, this paper systematically analyze the overall situation, development trend, key fields, and hot fields of agricultural eco-efficiency in the past two decades. It consists of two complementary parts, including systematic quantitative literature review (based on CiteSpace) and traditional literature review. (3) Results: Agricultural eco-efficiency has evolved significantly with the popularization of agricultural machinery and the wide application of science and technology in the field of agricultural ecology. Its future development relies on the advances in our knowledge on theories and hypothesis, evaluation methods, impact on “socio-economic ecological” system, and drivers and regulation of agricultural eco-efficiency. For each of these fields, we find that challenges still exist. At present, the quantitative methods and index selection are not unified. We should deeply analyze the internal and external driving force of the development and change of ecological efficiency by constructing a complete theoretical framework for the research of agricultural ecological efficiency. At the same time, new technologies and methods are needed to evaluate agricultural eco-efficiency, and a balanced consensus between the improvement of agricultural eco-efficiency and the improvement of the ecological environment should be formed through empirical research.

A Study on Optimal Agroforestry Planting Patterns in the Buffer Zone of World Natural Heritage Sites

As the protection layer of world natural heritage sites, the buffer zone should enable economic development while protecting the environment. To carry out agricultural activities in the buffer zone, it is necessary to balance agricultural development and environmental protection. In addition, the development of agroforestry has the benefits of developing the economy, maintaining biodiversity, and protecting the environment. In order to promote the coordination of environmental protection and community economic development, it is particularly important to scientifically select agroforestry planting patterns in the buffer zone of world natural heritage sites. This study utilized a mixed-methods research approach that included qualitative and quantitative research. Taking the buffer zone of Shibing Karst Heritage Site in southern China as an example, based on the seven agroforestry planting patterns surveyed in the buffer zone of the world natural heritage site, the four dimensions of net output value, carbon emission, environmental cost, and comprehensive livelihood score of different agroforestry planting patterns were calculated. The sorting scores of the values were calculated as Borda numbers. The sorting scores of the seven agroforestry planting patterns were B(A1) = 17, B(A2) = 18, B(A3) = 8, B(A4) = 8, B(A5) = 14, B(A6) = 12, and B(A7) = 7. The results showed that the priority sequence of seven agroforestry patterns was A2 > A1 > A5 > A6 > A3 = A4 > A7. A2 was the best among the seven agroforestry planting patterns, and A7 ranked last. The results can provide a quantitative evaluation basis for scientific optimization of agroforestry development planting patterns, and provide a reference for promoting the protection of world natural heritage.

Evaluation and Tradeoff Analysis of Ecosystem Service for Typical Land-Use Patterns in the Karst Region of Southwest China

Although many land-use patterns have been established to restore vegetation and eliminate poverty in the karst area in southwest China, the ecosystem services (ESs) of these patterns are still not fully understood. To compare the differences in seven typical monoculture patterns and three agroforestry patterns, their ESs and tradeoffs were analyzed within the Millennium Ecosystem Assessment Framework. Compared with the local traditional corn pattern, the marigold pattern improved provisioning, regulating, and cultural services by >100%. The pomegranate pattern provided far more provisioning services than the other patterns. The apple + soybean intercropping pattern reduced regulating services, and eventually, its Total ESs (TES) and ecosystem multifunctionality index (EMF) also decreased. Cultural services will be enhanced by the introduction of fruit trees, as well as intercropping. Orange + peach had the greatest negative tradeoffs between provisioning and regulating services (P-R), provisioning and supporting services (P-S), and provisioning and cultural services (P-C), which indicates that the provisioning services urgently require improvement. Peach + pumpkin intercropping decreased the negative tradeoffs of P-R, P-S, and P-C (all > 10%), while pomegranate + grass intercropping increased the negative tradeoffs of R-S and R-C (all > 100%). Our results suggest that all six of these patterns are worthy of promotion but the pomegranate pattern should be given priority. Among the three intercropping patterns studied herein, the apple + soybean pattern should be redesigned to improve performance.

Climate, Life Form and Family Jointly Control Variation of Leaf Traits

Variation in leaf traits may represent differences in physiological processes and environmental adaptative strategies. Using multivariate analyses, we investigated 13 leaf traits to quantify the trade-off in these traits and the trait-climate/biome relationships based on the China Plant Trait Database, which contains morphometric and physiological character information on 1215 species for 122 sites, ranging from the north to the tropics, and from deserts and grasslands to woodlands and forests. Leaf traits across the dataset of Chinese plants showed different spatial patterns along longitudinal and latitudinal gradients and high variation. There were significant positive or negative correlations among traits; however, with the exception of the leaf 13C:12C stable isotope ratio, there were no significant correlations between leaf area and other traits. Climate, life form, and family jointly accounted for 68.4% to 95.7% of trait variance. Amongst these forms of variation partitioning, the most important partitioning feature was the family independence of climate and life form (35.6% to 57.2%), while the joint effect of family and climate was 4.5% to 26.2%, and the joint effect of family and life form was 2.4% to 21.6%. The findings of this study will enhance our understanding of the variation in leaf traits in Chinese flora and the environmental adaptative strategies of plants against a background of global climate change, and also may enrich and improve the leaf economics spectrum of China.