Đánh giá việc sử dụng ba loại ảnh có độ phân giải trung bình và thấp trong việc xác định sự phân bố và ước tính sinh khối bốn loại rừng ngập mặn khu vực xã Đất Mũi, huyện Ngọc Hiển, tỉnh Cà Mau=Assessment three images with average and low resolutions in the determination of the distribution and biomass estimation for four mangrove species in Dat Mui hamlet, Ngoc Hien district, Ca Mau province

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Tác giả: Thị Hồng Điệp Nguyễn, Kiều Diễm Phan, Hoàng Trung Vũ

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Khoa học (Đại học Cần Thơ), 2024

Mô tả vật lý: tr.66-73

Bộ sưu tập: Metadata

ID: 159187

Thêm vào giỏ

Mangroves have an important role and great function in environmental protection and coastal ecosystem. Mangrove forest also has a role of climate regulation, reducing greenhouse gases and contributing to climate change mitigation. Therefore, forest biomass estimation is nescessary for suitable forest management. This study apply three types of low and medium resolution imagery (including MODIS, SPOT and LANDSAT) with the application of NDVI index (Normalized Difference Vegetation Index) to determine mangrove forest species distribution in the Dat Mui Commune, Ngoc Hien district, Ca Mau province. The study area are dominated by jour main species of mangrove forest, including: Rhizophora apiculata blume, Avicenna alba, mixed forest and combination system of shirmp and mangrove forest. The result shows that two of three images used to determine mangrove forest are of high reliability (i.e. 94.72 percent and 96.14 percent of SPOT and LANDSAT images, respectively) and of low reliability (i.e. 34.3 percent of the MODIS image). Total mangrove area is 9.555,21 ha in which the shrimp and mangrove forest combination is of the greatest (approximately, 48,48 percent)
next to that, rhizophora species (27,2 percent) and avicenna species (20,6 percent) are of the sequences while the lowest area is of the mixed forest (4,25 percent). Moreover, fresh biomass of each forest species is identified based on ages and trunk diameters with the greatest distribution on avicenna species (214,92 kg/ha/year), rhizophora species (188,42 kg/ha/year) and the combination system of shrimp and mangrove forest (113,05 kg/ha/year) with ratio between mangrove forest and shrimp at 6:4.Rừng ngập mặn có vai trò và chức năng to lớn trong việc bảo vệ môi trường và hệ sinh thái vùng ven biển, đồng thời rừng còn có vai trò điều hóa khí hậu, giảm lượng khí nhà kính và góp phần giảm nhẹ biến đổi khí hậu toàn cầu, do đó việc ước tính sinh khối rừng và rất cần thiết trong công tác quản lý rừng. Nghiên cứu thực hiện sử dụng 03 loại ảnh viễn thám độ phân giải thấp gồm ảnh MODIS, SPOT và LANDSAT với phương pháp tạo ảnh chỉ số thực vật NDVI (Normalized Diffence Vegetation Index) nhằm xác định hiện trạng phân bố rừng ngập mặn thuộc xã Đất Mũi, huyện Ngọc Hiển, tỉnh Cà Mau với 4 loại rừng gồm rừng đước, rừng mắm, rừng hỗn giao và rừng kết hợp thủy sản. Kết quả nghiên cứu cho thấy với 3 loại ảnh được sử dụng để xác định hiện trạng rừng, ảnh SPOT và ảnh LANDSAT có độ tin cậy là 94,72 phần trăm và 96, 14 phần trăm cao hơn so ảnh MODIS với độ tin cậy 34,3 phần trăm. Tổng diện tích rừng phân bố là 9.555,21 ha trong đó rừng đước kết hợp với thủy sản chiếm diện tích cao nhất chiếm 48,48 phần trăm
kế đến là diện tích rừng đước và rừng mắm chiếm 27,2 phần trăm và 20,6 phần trăm tổng diện tích và thấp nhất là rừng hỗn giao với 4,35 phần trăm tổng diện tích phân bố. Đồng thời nghiên cứu cũng xác định hàm lượng sinh khối tươi của từng loài rừng dựa theo các cấp tuổi và cấp đường kính khác nhau, trữ lượng sinh khối cao nhất phân bố trên rừng mắm với khoảng 214,92 kg/ha/năm, kế đến là sinh khối của rừng đước với 188,42 kg/ha/năm và thấp nhất phân bố trên rừng đước kết hợp với thủy sản là 113,05 kg/ha/năm (với tỉ lệ rừng tôm là 6:4).

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