Establishment Of Nature Reserves Research Articles

SDG- and GMAG-oriented analysis of multi scenarios spatiotemporal changes and evaluation of the effectiveness and potential of mangrove forests

ABSTRACT It is crucial to mangrove management by understanding its conservation efforts. This study proposed a spatiotemporal analysis model to evaluate mangrove changes in the Guangxi Beibu Gulf (GBG) and the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), focusing on past, present, and future dynamics. The analysis covered mangrove loss, stability, and gain from 1990 to 2020 and provided projections for 2020 to 2035 across multiple scenarios. Then further assessed the efficacy of past mangrove conservation with the Sustainable Development Goals (SDGs) and the prospective conservation potential with the Global Mangrove Alliance Goal (GMAG) indicators. Findings indicate that by 2020, the GBG and GBA had 81.65 km² and 40.92 km² of mangroves, respectively, with increases of 31.51% and 164.09% since 1990. Projected expansions are anticipated under all three scenarios during 2020- 2035, with the highest growth projected under the trend continuation scenario, followed by ecological restoration and protection, and economic development. While mangrove protection in these regions met SDG targets 6.6.1 and 14.5.1 from 2015 to 2020, the 80% conservation milestone set by GMAG for 2030 was not achieved, necessitating the establishment of nature reserves. The study offers novel insights for sustainable governance of mangrove forests at local, regional, and global levels.

Biodiversity Conservation in Xishuangbanna, China: Diversity Analysis of Traditional Knowledge Related to Biodiversity and Conservation Progress and Achievement Evaluation

Biodiversity plays an important role in maintaining the ecological balance of the earth. The study of traditional knowledge related to biological resources is a hot issue in the field of international biodiversity conservation. Xishuangbanna is a key area of biodiversity and a cultural hotspot of international significance. According to the Technical Regulation for Classification, Investigation, and Inventory of Traditional Knowledge Relating to Biological Diversity issued by the Ministry of Ecology and Environment, we investigated and catalogued the traditional knowledge related to biodiversity of the Jino people who have lived in Xishuangbanna for generations, and collected 490 entries of traditional knowledge related to biodiversity of the Jino people. Drawing on the traditional knowledge diversity index calculation method proposed by Wang Guoping, the overall traditional knowledge α-diversity index of the Jino people is 0.63, indicating that the richness of the traditional knowledge of the Jinuo people is relatively high. The traditional culture related to biodiversity, the traditional knowledge related to agricultural genetic resources, and the traditional technology related to the sustainable utilization of biological resources are relatively rich and diverse. The diversity index is 0.86, 0.82 and 0.79, respectively. In addition, Xishuangbanna has invested a lot of energy in biodiversity protection, including the establishment of nature reserves, botanical gardens, zoos, ecological tea gardens and other species reserves, and the promulgation of laws and policies related to biodiversity protection, and has achieved remarkable results in in situ protection and ex situ protection. On the basis of analyzing the progress and achievements of biodiversity conservation in Xishuangbanna, this study points out that Xishuangbanna faces challenges such as the loss of traditional knowledge, insufficient conservation efforts, and great changes in land use, and puts forward corresponding suggestions.

Ensemble SDMs reveal the effect of environmental suitability and nature reserves on conserving Chinese pangolins in Guangdong, China

Identifying species distribution patterns and threatened factors is essential for wildlife conservation. For the critically endangered Chinese pangolin, most studies have emphasized negative human interference and ignored the effect of environmental suitability and positive human intervention on altering species distribution patterns. We took Guangdong Province as the research area and obtained census data of the Chinese pangolin. Combined with five types of environmental variables, including climatic, geographical, human, soil and vegetation, we used five algorithms in BIOMOD2 to construct an ensemble species distribution model (SDM) of the Chinese pangolin. The importance and response curves of environmental variables were also obtained. We used the cutoff as a threshold to classify habitat or non-habitat, calculated the habitat coverage of established nature reserves by overlay analysis, and visualized the conservation gaps. The results indicate that the potential distribution range of the Chinese pangolin is wide, fragmented and determined by multiple factors. The average annual temperature (highly correlated with elevation) and the highest temperature in the warmest month were the main influencing factors (contribution rate > 10 %), and the distance from nature reserves and human footprint index were secondary factors (contribution rate > 5 %). The established nature reserve network covers approximately 23 % of the potential habitat of the Chinese pangolin. The proposed Nanling National Park seems incapable of protecting the widely distributed Chinese pangolins. In eastern and northern Guangdong, including Meizhou, Heyuan, Shaoguan and Huizhou and Qingyuan cities, there is still a large area of habitat suitable for the Chinese pangolin that is not well protected. We suggest further expanding the current nature reserve network to absorb suitable habitats of Chinese pangolins from adjacent areas and optimizing the spatial arrangement to improve conservation efficiency.

Tracking the dynamics of tidal wetlands with time-series satellite images in the Yangtze River Estuary, China

ABSTRACT Tidal wetlands provide a variety of ecosystem services to coastal communities but suffer severe losses due to anthropogenic activities in the Yangtze River Estuary (YRE). However, the detailed dynamics of tidal wetlands have not been well studied with sufficient spatiotemporal resolution. Here, we proposed a rapid classification method that integrates the COntinuous monitoring of Land Disturbance (COLD) algorithm and Median Composite (MC) based on the dense Landsat time series to track the dynamic processes of tidal wetlands in the YRE from 1990 to 2020. The results showed that the COLD-MC demonstrated remarkable effectiveness in detecting the change of tidal wetlands and excellent overall accuracy and kappa coefficient ranging from 90% to 96% and 0.89–0.95, respectively. The overall accuracy of change detection was 97% with an absolute error of 0.4 years. We found that the total area of tidal wetlands experienced a net loss of 59.75 km2 in the YRE, but the gain and loss of the study period were 1556.07 and 1615.82 km2, respectively. Land reclamation, sediment reduction, and Spartina alterniflora invasion pose significant threats to tidal wetlands. Sustainable management could be implemented through the establishment of nature reserves and ecological sediment enhancement engineering projects.

Nature reserves and reforestation expend the potential habitats for endangered plants: A model study in Cangshan, China

The loss of biodiversity is one of the greatest challenges in the world. Nature Reserves are widely recognized as an effective strategy to protect against biodiversity crises. Over the past 40 years, the vegetation coverage of the Cangshan Reserve and its surrounding areas has increased significantly largely due to the reforestation project. In this study, we specifically evaluated the capacity of nature reserves and reforestation efforts to increase the area of potential habitats for endangered plants, using historical and current species distribution models (SDM). Our findings revealed that the highly suitable area for endangered species constituted 31.5 % of Cangshan Reserve and 3.3 % of the total study area in 1980 model. However, in the 2020 model, the highly suitable area increased to 37.9 % of Cangshan Reserve and 3.9 % of the total area. In total, the highly suitable area in 2020 exceeded that of 1980 by 37.12 km2. The significant increase of the highly suitable area can be attributed to the plantations within the Cangshan Reserve. Despite a noted increase in vegetation cover outside the reserve, the present study did not find a significant expansion in suitable habitats outside Cangshan Reserve. In conclusion, our study suggests that reforestation policy alone may not suffice to expand the potential habitats for endangered plants, a combined approach involving the establishment of nature reserves and the implementation of reforestation programs may prove to be a more effective strategy in the increase of potential habitats for these rare and endangered plants.

Assessing the conservation effectiveness of national nature reserves in China

Establishing nature reserves (NRs) to protect habitats by selecting and reducing human activities (HA) is one of the measures to conserve biodiversity. Scientific assessment of the conservation effectiveness of NRs can provide useful references for managing NRs. However, further study is required to evaluate habitat quality (HQ) and HA and the response of HQ to HA in Chinese NRs to identify the conservation effectiveness of national NRs in China. To fill the gaps, this study attempted to evaluate the conservation effectiveness of NRs by analyzing the changes in HQ and HA and the response of HQ to HA. The results showed that the HQ improvement area was 53.494% during 1990–2020, and HQ rebounded by 0.332% after 2010. Moreover, HA positively impacted HQ in general, with heterogeneous categories. These findings suggest that the ecological conservation in the NRs are effective. Notably, HA's positive role in enhancing HQ continued to rise by 36.364%. Ecological transformation of HA in the NRs is the main reason. However, HA has adverse effects on HQ due to the HA diversity and the NRs vulnerability. This study contributes to the assessment of conservation effects and the development of better management plans for NRs.

The Impact of Establishment of Nature Reserves on the Urban–Rural Income Gap: Evidence from County-Level Analysis in China

While China has seen an economic boom in recent decades, ecological issues are becoming increasingly challenging, with biodiversity seriously threatened. Establishing nature reserves (NRs) is deemed a feasible measure to ease ecological pressure, but few studies have evaluated the impact of the establishment of NRs on the urban–rural income gap. Therefore, based on the county-level panel data from 2010 to 2018, this study analyzed in depth the effects of the establishment of NRs on the urban–rural income gap in China. The results suggested that establishing NRs is beneficial to bridging the income gap between urban and rural areas, especially in the western and the northeastern regions. In contrast to other levels (provincial level, city level, and county level), the establishment of national-level NRs demonstrated a more prominent effect on narrowing the urban–rural income gap. It is thus proposed to improve corresponding laws to strengthen the protection of NRs, especially for those located in the western and northeastern regions, where the increase in eco-economic compensation and development of tourism brands for the ecological tourism industry are of necessity. Taken together, this study provides evidence that the establishment of NRs alleviates the urban–rural income gap in China.

Distribution pattern and change prediction of Phellodendron habitat in China under climate change.

Phellodendron has always been of great significance in promoting human health and ecological restoration. However, human activities and climate change have severely affected habitat, population dynamics and sustainable use of Phellodendron. Little is known about the geographical distribution pattern and their responses to climate change of Phellodendron. In order to reveal the impact of climate change on Phellodendron, we conducted a study based on natural distribution data of two species (297 occurrence points), 20 environmental factors, and an optimized MaxEnt model. Our results identified the main environmental factors influencing Phellodendron, predicted their potential geographical distribution, and assessed migration trends under climate change in China. Our analysis showed that Ph. amurense and Ph. chinense have potential suitable habitats of 62.89 × 104 and 70.71 × 104 km2, respectively. Temperature and precipitation were found to play an essential role in shaping the present geographical distribution of Phellodendron populations. Based on two future climate scenarios, we forecasted that the potential suitable habitat of Ph. amurense would decrease by 12.52% (SSP245) and increase by 25.28% (SSP585), while Ph. chinense would decline by 19.61% (SSP245) and 15.78% (SSP585) in the late-21st century. The potential suitable habitats of Ph. amurense and Ph. chinense would shift to northward and westward, respectively. Hydrothermal change was found to be the primary driver of the suitable habitat of Phellodendron populations in the future. We recommend establishing nature reserves for existing Phellodendron populations, especially Ph. chinense. Our study provided a practical framework for the impact of climate change on the suitable habitat of Phellodendron species and guided regional cultivation, long-term conservation, and sustainable use.

Analysis of Growing Season Normalized Difference Vegetation Index Variation and Its Influencing Factors on the Mongolian Plateau Based on Google Earth Engine.

Frequent dust storms on the Mongolian Plateau have adversely affected the ecological environmental quality of East Asia. Studying the dynamic changes in vegetation coverage is one of the important means of evaluating ecological environmental quality in the region. In this study, we used Landsat remote sensing images from 2000 to 2019 on the Mongolian Plateau to extract yearly Normalized Difference Vegetation Index (NDVI) data during the growing season. We used partial correlation analysis and the Hurst index to analyze the spatiotemporal characteristics of the NDVI before and after the establishment of nature reserves and their influencing factors on the GEE cloud platform. The results showed that (1) the proportion of the region with an upwards trend of NDVI increased from 52.21% during 2000-2009 to 67.93% during 2010-2019, indicating a clear improvement in vegetation due to increased precipitation; (2) the increase in precipitation and positive human activities drove the increase in the NDVI in the study region from 2000 to 2019; and (3) the overall trend of the NDVI in the future is expected to be stable with a slight decrease, and restoration potential is greater for water bodies and grasslands. Therefore, it is imperative to strengthen positive human activities to safeguard vegetation. These findings furnish scientific evidence for environmental management and the development of ecological engineering initiatives on the Mongolian Plateau.

The role of nature reserves in conservation effectiveness of ecosystem services in China

Establishing nature reserves (NRs) is a common method to avoid biodiversity loss and degradation of ecosystem services (ESs). The evaluation of ESs in NRs and the exploration of associated influencing factors are the basis for improving ESs and management. However, the ES effectiveness of NRs over time remains questionable, namely due to the heterogeneity of landscape characteristics inside and outside of NRs. This study (i) quantifies the role of 75 NRs in China in maintaining ESs (i.e., net primary production (NPP), soil conservation, sandstorm prevention and water yield) from 2000 to 2020, (ii) reveals the trade-offs/synergies, and (iii) identifies the main influencing factors of the ES effectiveness of NRs. The results show that more than 80% of NRs had positive ES effectiveness, which was greater in older NRs. For different ESs, effectiveness over time increases for NPP (E_NPP), soil conservation (E_SC) and sandstorm prevention (E_SP) but declines for water yield (E_WY). There is a clear synergistic relationship between E_NPP and E_SC. Moreover, the effectiveness of ESs is closely correlated with elevation, precipitation, and perimeter area ratio. Our findings can provide important information to support site selection and management of reserves to improve the delivery of critical ecosystem services.

Analysis on the establishment of natural reserves and the transfer of agricultural labor forces taking Jiangxi Province as an example*

Purpose The purpose of this study was to conduct a comprehensive analysis of the impact and its mechanism on the transfer of agricultural labor forces in the surrounding areas resulting from the establishment of a natural reserve, which holds great significance. The significance of this analysis is on the ecological protection of the natural reserve and the coordinated development of local social economy.Design/methodology/approach This study first performs an analysis on the impact and its mechanism on the establishment of the natural reserve on the transfer of agricultural labor forces from two aspects, which are push and pull factors. Then, based on county panel data in Jiangxi Province from 1995 to 2012, this study builds a generalized difference-in-difference model and performs an empirical study on the impact, heterogeneity and its mechanism on the establishment of the natural reserve on the transfer of agricultural labor forces.Findings The empirical analysis reveals that the establishment of natural reserves would significantly promote the transfer of agricultural labor forces to non-agricultural sectors. The robust test and placebo test with changed estimation methods verify the robust of the result. The result passes the parallel trend test and shows that the impact is most significant within one year after the implementation of the policy. From the mechanism analysis, the impact mainly comes from the “push” effect brought by the restricted development of agricultural production and primary industry on agricultural labor forces, and the “pull” effect brought by the development of local tertiary industry.Originality/value The conclusion of this study enriches the understanding of the internal mechanism between the establishment of natural reserves and the transfer of agricultural labor forces from the push and pull factors, and can provide reference for formulating policies to promote the coordinated development of natural reserve construction and regional social economy.

Monitoring the light pollution changes of China’s mangrove forests from 1992-2020 using nighttime light data

Mangrove forests are one of the most biologically diverse and productive ecosystems on Earth. They are important breeding and nursing grounds for amphibians, invertebrates, birds, fish, etc. Light pollution may cause serious degradation of biodiversity in the ecosystem. A report of the long-term holistic views of light pollution changes is essential for sustainable management of mangrove ecosystems. However, to date, such studies have rarely been carried out. This study aimed to monitor the long-term light pollution changes of China’s mangrove forests. To achieve this goal, we used time-series nighttime light (NTL) data to build continuous light pollution data. NTL maps made with DMSP-OLS (DNL) or NPP-VIIRS (VNL) are widely utilized in research on human activity. However, DMSP and VIIRS images are different in spatial resolution, radiation resolution, and data saturation. Thus, this study innovatively set an optimal threshold for generating consistent light pollution data in mangrove areas from 1992-2020. The results showed that: (1) the proportion of light-polluted mangrove forests in China increased from 12% in 1992 to 52% in 2020; (2) the largest net increase occurred in Guangxi with an area of 4,086 ha, followed by Guangdong (3,365 ha) and Hainan (2,944 ha); (3) Zhejiang had the largest proportion of net growth (from 0% in 1992 to 99% in 2020), followed by Hainan (66%) and Fujian (59%). Mangrove forests have been protected and restored for decades in China; this study indicates that the establishment of nature reserves is effective in preventing the light pollution of mangroves and provides the first long-term multi-temporal dataset of light pollution in China’s mangrove forests. This comprehensive information could support related studies and facilitate the development of applicable coastal management strategies in China.

Controlling heavy metals pollution is vital for the restoration of carbon and nitrogen transformation function of mangrove ecosystems in the Greater Bay Area, China

Pollutants, especially for heavy metals (HMs), discharged from anthropogenic activities are the potential risks to newly planted mangrove forests in the restoration process. Thus, it is crucial to investigate how HMs affect the biological processes that take place in these mangrove habitats, e.g., the transformation of carbon and nitrogen. In this study, correlations between HMs pollution, carbon storage, and nitrogen biotransformation in the Great Bay Area (GBA) were examined at five typical sites with different mangrove restoration ages. The results indicated that there were distinct differences in the concentration distribution of HMs (ranges: 0.2–369.7 mg/kg) at five sample sites, with Cd (0.2–1.6 mg/kg) being the heavily polluted element in sediments. The fluctuation of SOC (16.0–25.7 mg/kg), δ13C (−27.5 to −20.2), and NO3−-N (1.2–3.3 mg/kg) was positively correlated with the content of HMs in sediments, indicating that these components in mangrove ecosystems might have similar emission source and pose a potential threat to mangrove carbon storage. Notably, sediments with high HMs concentration decelerated carbon decomposition rate of mangrove ecosystems, especially for sites with newly planted mangrove forest. Moreover, a large abundance of Euryarchaeota was found in the HO site, suggesting that HMs may promote the conversion of carbon to CH4. The inflow of contaminants also induced the significant increasing proportion of microorganisms related to nitrogen fixing, denitrification, and dissimilarity nitrogen reduction processes, resulting a decline in the stability of co-occurrence network of nitrogen transformation. Fortunately, mangrove site with the establishment of natural reserves and controlling pollutant discharge could contribute to the rapid restoration of its ecological function, e.g., nutrient cycling and co-occurrence stability, in SZ site. Therefore, future management should focus on the decrease of pollutants discharge and pay more attention to the ecological function restoration of mangrove wetlands in the GBA.

Climate change impacts the distribution of Quercus section Cyclobalanopsis (Fagaceae), a keystone lineage in East Asian evergreen broadleaved forests

East Asian evergreen broadleaved forests (EBFLs) harbor high species richness, but these ecosystems are severely impacted by global climate change and deforestation. Conserving and managing EBLFs requires understanding dominant tree distribution dynamics. In this study, we used 29 species in Quercus section Cyclobalanopsis—a keystone lineage in East Asian EBLFs—as proxies to predict EBLF distribution dynamics using species distribution models (SDMs). We examined climatic niche overlap, similarity, and equivalency among seven biogeographical regions’ species using ‘ecospat’. We also estimated the effectiveness of protected areas in the predicted range to elucidate priority conservation regions. Our results showed that the climatic niches of most geographical groups differ. The western species under the Indian summer monsoon regime were mainly impacted by temperature factors, whereas precipitation impacted the eastern species under the East Asian summer monsoon regime. Our simulation predicted a northward range expansion of section Cyclobalanopsis between 2081 and 2100, except for the ranges of the three Himalayan species analyzed, which might shrink significantly. The greatest shift of highly suitable areas was predicted for the species in the South Pacific, with a centroid shift of over 300 km. Remarkably, only 7.56% of suitable habitat is currently inside protected areas, and the percentage is predicted to continue declining in the future. To better conserve Asian EBLFs, establishing nature reserves in their northern distribution ranges, and transplanting the populations with predicted decreasing numbers and degraded habitats to their future highly suitable areas, should be high-priority objectives.

Spatiotemporal Characteristics of the Coupled Coordination Degree of Ecosystem Services Supply and Demand in Chinese National Nature Reserves

Nature reserves (NRs) are the main components of protected areas and geographic spaces, with unique natural and cultural resources. The establishment of nature reserves has not only strengthened the protection of specific species but has also played a vital role in the protection of ecosystem services (ESs). However, few studies have been conducted to systematically assess the effectiveness of nature reserves from the perspective of ecosystem services supply and demand (S&D) or make comparisons between the conservation effects of different types of nature reserves. This study analyzed the spatiotemporal characteristics of ecosystem service supply and demand in 412 Chinese national nature reserves. The results showed that both supply and demand for ecosystem services per unit area show a spatial pattern of increasing from west to east. The supply-demand matching pattern is dominated by high supply-high demand (H-H) and low supply-high demand (L-H) in the central and eastern regions, and high supply-low demand (H-L) and low supply-low demand (L-L) in the northeast, northwest, and southwest regions. The coupling coordination degree (CCD) of ecosystem services supply and demand increased from 0.53 in 2000 to 0.57 in 2020, and the number of NRs reaching the coordinated level (>0.5) increased by 15 from 2000 to 2020, representing 3.64% of the total number of protected areas. Steppe meadows, ocean coasts, forest ecosystems, wildlife, and wild plant types of nature reserves all improved more obviously. This provides a scientific basis for strengthening the ecological and environmental supervision of nature reserves, and the research methods and ideas can provide references for similar research.

Does the establishment of nature reserves increase rural residents' income? : Empirical evidence from China based on PSM-DID.

Clarifying the impact of nature reserves on rural residents' income is of great significance to the organic integration of environmental protection and rural residents' income improvement. Based on the panel data of 600 counties from nine provinces in China, ranging from 2010 to 2019, this study employs the quasi-experimental method of Difference in Difference and Propensity Score Matching (PSM-DID) to examine how rural resident's income is influenced by the establishment of nature reserves. It is found that (1) Nature reserves, with a positive impact on rural resident's income, bring more earnings to the rural residents. (2) The impact varies with the heterogeneity of natural reserve types. That is, national and natural parks can increase rural residents' income, while the ones with wildlife or remote desert ecosystem play a limited role. (3) The increased income is mainly originated from the development of tourism, the improvement of facilities and the enhancement of ecosystem services. On this basis, multiple methods are proposed to promote rural residents' income and livelihood security of local communities. Policy recommendations are brought forth as well, including the focus on guaranteeing the livelihood security of rural residents nearby nature reserves where wildlife and remote desert ecosystem are protected.

Status, threats and the conservation of endemic species in the Yarlung Zangbo river basin

The Yarlung Zangbo river extends through the southern area of the Tibet Plateau at the highest elevation of any large river in the world. It supports many unique and endemic species, but global warming, proposed and existing hydropower developments, and the invasion of non-native species are significant threats to its native aquatic biodiversity. Some endemic species, including fishes (Glyptosternum maculatum, Schizothorax oconnori, Schizothorax macropogon, Schizophygopsis younghusbandi, Ptychobarbus dipogon and Oxygymnocypris stewartii), water birds (Grus nigricollis and Haliaeetus albicilla) and mammals (Lutra lutra), have experienced great ecological and physical challenges. To ensure a sustainable development pathway, some specific conservation measures should be undertaken, including the establishment of natural reserves in sensitive areas, and more research and ecological monitoring. This study is a significant reference and example for managers developing strategies to conserve aquatic biodiversity in large, highaltitude river basins within mountainous settings.

Conservation of forest ecosystems in regional complex nature reserves

Based on the analysis of expedition, stock, published and official cadastral materials on the specially protected natural areas, the article characterizes complex (landscape) nature reserves of the Vologda region in the context of the landscape concept of formation of the network of specially protected natural areas in the region, and gives assessment of the compliance of the nature reserves with biodiversity conservation tasks under the taiga zone conditions. The history of establishment of nature reserves, the species and age composition of forests, the typological diversity of forests, availability of valuable natural areas, rare and protected species of plants and animals in 75 nature reserves were analyzed.

Detecting annual anthropogenic encroachment on intertidal vegetation using full Landsat time-series in Fujian, China

ABSTRACT Intertidal vegetation plays an essential role in habitat provision for waterbirds but suffers great losses due to human activities. However, it is challenging in tracking the human-driven loss and degradation of intertidal vegetation due to rapid urbanization in a high temporal resolution. In this study, a methodological framework based on full Landsat time-series (FLTS) is proposed to detect the year of change (YOC) of intertidal vegetation converted to impervious surfaces (ISs) and artificial ponds (APs), and the condition of the remaining intertidal vegetation was also assessed by FLTS, in the Fujian province, a subtropical coastal area lying in southeast China. The accuracies of the YOC detection of intertidal vegetation converted to IS and AP were 91.84% and 72.73%, with mean absolute errors of 0.26 and 1.06, respectively. The total areas of intertidal vegetation encroached by IS and AP were 31.68 km2 and 23.85 km2, respectively. Most ISs were developed later than 2010, and most APs were developed earlier than 2005, which are highly related to the implementation of local policies for economic development. The remaining intertidal vegetation in growing, stable, and degraded conditions were 43.05%, 56.38%, and 0.57%, respectively. The results indicated that areas of intertidal vegetation were reclaimed for anthropogenic uses at a considerable rate, although the intertidal vegetation still increased owing to natural development after the establishment of natural reserves. The study demonstrates that the FLTS has capacities in monitoring the dynamics in coastal zones solely for its dense earth observations.

Evaluation of Mangrove Wetlands Protection Patterns in the Guangdong–Hong Kong–Macao Greater Bay Area Using Time-Series Landsat Imageries

The protection of mangroves through nature reserves has been demonstrated to be effective. There were many studies evaluating the mangrove protection effect. However, the evaluation of mangrove growth quality with positive or negative growth trends, as well as restoration potential against disturbance in nature reserves, is still lacking. Thus, this study proposed a hierarchical evaluation framework for mangrove protection in nature reserves, which takes long-term metrics at three levels of loss and gain areas, patch pattern dynamics, and pixel growth trends into account. The continuous change detection and classification (CCDC) was utilized to identify the change condition of mangroves in six nature reserves of the Guangdong–Hong Kong–Macao Greater Bay Area. The Entropy Weight Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was utilized for scores evaluation of protection effort comparison from 2000 to 2020. The study results had the following three main findings. Firstly, the mangrove forest area increased by about 294.66 ha in four reserves and slightly decreased by about 58.86 ha in two. Most reserves showed an improved patches intact pattern and more positive growth trends. Secondly, the establishment of nature reserves and afforestation were the main causes of mangrove area gain. Until 2010, aquaculture, agriculture, and urban development were the biggest threats to mangroves. Finally, the protection of the reserves was successful in the early decades, but the general evaluation scores showed a decline in recent years once we considered the growth trends for quality. The proposed hierarchical evaluation methods provide a new sight to research the impacts of abrupt change and protection resilience status of the gradual restoration of nature reserves.