Evaluating the Effectiveness of Conservation on Mangroves: A Remote Sensing-Based Comparison for Two Adjacent Protected Areas in Shenzhen and Hong Kong, China

Abstract

Mangroves are ecologically important ecosystems and globally protected. The purpose of this study was to evaluate the effectiveness of mangrove conservation efforts in two adjacent protected areas in China that were under the management policies of the Ramsar Convention (Mai Po Marshes Nature Reserve (MPMNR), Hong Kong) and China's National Nature Reserve System (Futian Mangrove National Nature Reserve (FMNNR), Shenzhen). To achieve this goal, eleven Landsat images were chosen and classified, areal extent and landscape metrics were then calculated. The results showed that: from 1973-2015, the areal extent of mangroves in both reserves increased, but the net change for the MPMNR (281.43 hm 2 ) was much higher than those of the FMNNR (101.97 hm 2 ). In general, the area-weighted centroid of the mangroves in FMNNR moved seaward by approximately 120 m, whereas in the MPMNR, the centroid moved seaward even farther (410 m). Although both reserves saw increased integrality and connectivity of the mangrove patches, the patches in the MPMNR always had higher integrality than those in the FMNNR. We concluded that the mangroves in the MPMNR were more effectively protected than those in the FMNNR. This study may provide assistance to the formulation of generally accepted criteria for remote sensing-based evaluation of conservation effectiveness, and may facilitate the development of appropriate mangrove forest conservation and management strategies in other counties.

Monitoring the Invasion of Spartina alterniflora Using Multi-source High-resolution Imagery in the Zhangjiang Estuary, China

“…The scale factor determines the size of the image objects; the larger the scale parameter, the more objects can be fused and the larger the objects grow [38].The homogeneity criterion is composed of a shape and compactness factor that controls the clustering decision process [27]. The shape factor balances the spectral homogeneity with the shape of the objects, while the compactness factor balances the compactness with smoothness [39,40]. Users can set values from 0 to 1 for the shape and compactness factor to determine objects at a certain level of scale.…”

Zonation and Directional Dynamics of Mangrove Forests Derived from Time-Series Satellite Imagery in Mai Po, Hong Kong

“…There are only a few studies on further spatial analysis of mangrove changes at a large scale. Weighted centroids were calculated to analyze mangrove spatial dynamics [15], but mangrove forest dynamics still cannot be fully understood using existing methods of estimation. More information describing the process of mangrove zonation changes, in terms of the spatial changes aspect, is needed.…”

Quantifying Urban Land Sprawl and its Driving Forces in Northeast China from 1990 to 2015

“…The overall accuracy of the confusion matrix was used to assess the agreement between the results and the ground-truth [42]. The land resource maps, and river and road data from the National Earth System Science Data Sharing Infrastructure, National Science and Technology Infrastructure of China (http://www.geodata.cn), Advanced Spaceborne Theemal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM V1) with 30 m spatial resolution acquired from the United States Geological Survey (USGS) Center (http://glovis.usgs.gov/), photos from Google Earth and the historic investigation points from local experts were used as auxiliary data to achieve accurate land cover classification.…”