Co-occurrence of biodiversity, carbon storage, coastal protection, and fish and invertebrate production to inform global mangrove conservation planning

Mangrove Against Invasive Snails: Aegiceras corniculatum Shows a Molluscicidal Effect on Exotic Apple Snails (Pomacea canaliculata) in Mangroves

Apple snails (Pomacea canaliculata), one of the 100 most serious invasive species in the world, have invaded mangrove wetlands due to their salinity tolerance. We firstly prepared a plant molluscicide against apple snails based on the mangrove Aegiceras corniculatum in coastal wetland. The effects of four mangrove extracts from A. corniculatum, including ethanol extract (EE), petroleum ether extract (PEE), ethyl acetate extract (EAE), and n-butanol extract (BE), were studied for molluscicidal activity against apple snails in a saline environment. The LC50 values at 48 h of EE, PEE, EAE, and BE were 25 mg/L, 123 mg/L, 170 mg/L, and 14 mg/L, respectively. BE had the highest molluscicidal value (96.7%) against apple snails at 48 h. At 48 h, BE of A. corniculatum leaves significantly decreased the soluble sugar content, soluble protein content, acetylcholinesterase, and glutathione of apple snails to 4.25 mg/g, 29.50 mg/g, 947.1 U/gprot, and 6.22 U/gprot, respectively, compared to those in the control. The increased BE concentration significantly enhanced the malondialdehyde and aspartate aminotransferase contents to 4.18 mmol/gprot and 18.9 U/gprot at 48 h. Furthermore, the damage in the hepatopancreas tissue of apple snails increased, and the cellular structure became necrotic as the concentration of BE from A. corniculatum increased. The content of palmitic acid in BE of A. corniculatum leaves was the highest (10.9%), possibly be a toxic ingredient against apple snails. The n-butanol extract of A. corniculatum leaves showed a potential to control apple snails in the brackish water, and its plantation was beneficial to control the further spread of apple snails in mangrove wetlands.

Mangrove Extraction Algorithm Based on Orthogonal Matching Filter-Weighted Least Squares

High-precision extraction of mangrove areas is a crucial prerequisite for estimating mangrove area as well as for regional planning and ecological protection. However, mangroves typically grow in coastal and near-shore areas with complex water colors, where traditional mangrove extraction algorithms face challenges such as unclear region segmentation and insufficient accuracy. To address this issue, in this paper we propose a new algorithm for mangrove identification and extraction based on Orthogonal Matching Filter-Weighted Least Squares (OMF-WLS) target spectral information. This method first selects GF-6 remote sensing images with less cloud cover, then enhances mangrove feature information through preprocessing and band extension, combining whitened orthogonal subspace projection with the whitened matching filter algorithm. Notably, this paper innovatively introduces Weighted Least Squares (WLS) filtering technology. WLS filtering precisely processes high-frequency noise and edge details in images using an adaptive weighting matrix, significantly improving the edge clarity and overall quality of mangrove images. This innovative approach overcomes the bottleneck of traditional methods in effectively extracting edge information against complex water color backgrounds. Finally, Otsu's method is used for adaptive threshold segmentation of GF-6 remote sensing images to achieve target extraction of mangrove areas. Our experimental results show that OMF-WLS improves extraction accuracy compared to traditional methods, with overall precision increasing from 0.95702 to 0.99366 and the Kappa coefficient rising from 0.88436 to 0.98233. In addition, our proposed method provides significant improvements in other metrics, demonstrating better overall performance. These findings can provide more reliable technical support for the monitoring and protection of mangrove resources.

Endophytic Fungal Diversity of Mangrove Ferns Acrostichum speciosum and A. aureum in China

Microbial communities are an important component of mangrove ecosystems. In order to reveal the diversity of endophytic fungi in the mangrove ferns Acrostichum speciosum and A. aureum in China, the internal transcribed spacer (ITS) regions of endophytic fungi in four plant tissues (leaves, petioles, roots, and rhizomes) from three locations (Zhanjiang, Haikou, and Wenchang) were sequenced. The richness, species composition, and community similarity were analyzed. The main results are as follows: the dominant fungi in A. speciosum and A. aureum belonged to the phyla Ascomycota and Basidiomycota, accounting for more than 75% of the total identified fungi; in terms of species composition at the operational taxonomic unit (OTU) level, the endophytic fungi in A. aureum were more diverse than those in A. speciosum, and the endophytic fungi in rhizomes were more diverse than in other tissues. In Zhanjiang, both A. speciosum and A. aureum showed the richest diversity of endophytic fungi, both at the OTU classification level and in terms of species composition. Conversely, the richness of endophytic fungi in the samples of A. speciosum from Wenchang and Haikou is extremely low. The regional differences in dominant fungi increase with the degrading of taxonomic levels, and there were also significant differences in the number of unique fungi among different origins, with Zhanjiang samples having a larger number of unique fungi than the other locations. There were significant differences in the dominant fungi among different tissues, with Xylariales being the dominant fungi in rhizomes of A. speciosum and Hypocreales being the dominant fungi in the petioles, roots, and rhizomes of A. aureum. Overall, the community similarity of endophytic fungi among locations is moderately dissimilar (26-50%), while the similarity between tissues is moderately similar (51-75%). The low diversity of endophytic fungi could be one of the main reasons for the endangerment of A. speciosum. The protection of the diversity of endophytic fungi in the underground parts of A. speciosum is essential for the conservation of this critically endangered mangrove fern.

Priority areas to protect mangroves and maximise ecosystem services

Anthropogenic activities threaten global biodiversity and ecosystem services. Yet, area-based conservation efforts typically target biodiversity protection whilst minimising conflict with economic activities, failing to consider ecosystem services. Here we identify priority areas that maximise both the protection of mangrove biodiversity and their ecosystem services. We reveal that despite 13.5% of the mangrove distribution being currently strictly protected, all mangrove species are not adequately represented and many areas that provide disproportionally large ecosystem services are missed. Optimising the placement of future conservation efforts to protect 30% of global mangroves potentially safeguards an additional 16.3 billion USD of coastal property value, 6.1 million people, 1173.1 Tg C, and 50.7 million fisher days yr-1. Our findings suggest that there is a pressing need for including ecosystem services in protected area design and that strategic prioritisation and coordination of mangrove conservation could provide substantial benefits to human wellbeing.