The contribution of leaf angle to photoprotection in the mangroves Avicennia marina (Forssk.) Vierh. and Bruguiera gymnorrhiza (L.) Lam. under field conditions in South Africa

Flora ◽  
1999 ◽  
Vol 194 (3) ◽  
pp. 267-275 ◽  
Author(s):  
Arnd V. Tüffers ◽  
Gonasageran Naidoo ◽  
Dieter J. Von Willert
Bothalia ◽  
1982 ◽  
Vol 14 (1) ◽  
pp. 123-125
Author(s):  
P. J. Weisser ◽  
C. J. Ward

The destruction of the Phoenix!Hibiscus and Barringtonia racemosa Communities described by Venter in 1972 on the southern shores of Richards Bay is reported. The cause was the artificial openingof a new mouth about 5,5 km south of the original mouth, which increased tidal range and salinity. These swamp communities occupied a narrow band about 6 ha in area behind the Bruguiera gymnorrhiza Community. An estimated 95 % of the communities was affected and only on the landward border were some isolated remnants of species such as Acrostichum aureum, Hibiscus tiliaceus and Phoenix reclinata detected .Young stands of  Phragmites australis, seedlings of  Bruguiera gymnorrhiza and Avicennia marina and epipelic algae are recoIonizing the affected area. 


2020 ◽  
Vol 11 (1) ◽  
pp. 1-10
Author(s):  
Agus Putra A. Samad ◽  
Pitri Agustina ◽  
Mus Herri

Langsa merupakan salah satu kota pesisir Aceh yang memiliki kawasan mangrove yang  sangat  potensial.  Kota  ini  memiliki  panjang  garis  pantai  16  km dengan luas kawasan mangrove sebesar 7.837 Ha. Keberadaan mangrove di wilayah ini menjadi aset strategis untuk dikembangkan menjadi basis kegiatan ekonomi untuk memakmurkan masyarakat dan meningkatkan pendapatan  asli  daerah. Tujuan utama penelitian ini adalah untuk melestarikan potensi sumberdaya ekosistem mangrove yang ada di Kota Langsa agar dapat memberikan fungsi ekologis dan ekonomis secara berkesinambungan kepada masyarakat disekitarnya. Kajian ini dilakukan menggunakan metode survei, analisa laboratorium dan observasi lapangan. Hasil pengamatan terhadap komposisi jenis tumbuhan yang terdapat di ekosistem mangrove menunjukkan 8 jenis tumbuhan mangrove yaitu: jenis Avicennia lanata, Avicennia marina, Bruguiera gymnorrhiza, Bruguiera parviflora, Rhizophora apiculata, Rhizophora  mucronata, Sonneratia Caseolaris dan Xylocarpus granatum. Nilai rata-rata parameter kualitas air di ekosistem mangrove secara beturut-turut adalah DO (6.3 ppm),salinitas (27 ‰), pH tanah dasar (6.0), pH tanah permukaan (5.08), pH air (7.33), suhu (30 oC) dan kecerahan (5 m).  Perhitungan terhadap nilai manfaat ekosistem mangrove meliputi: 1) Nilai manfaat langsung perikanan tangkap: Rp. 8.710.000.000 per tahun, 2) Nilai manfaat budidaya tambak: Rp. 93.940.000.000,- per tahun, 3) Nilai penahan abrasi dan banjir: Rp. 300.000.000,- per hektar per tahun, 4) Nilai sebagai penyediaan unsur hara: Rp. 28.634.000,- per tahun, 5) Nilai manfaat pilihan: Rp. 210.000.000,- per tahun dan 6) Nilai manfaat keberadaan: Rp. 1.464.493.000,- per tahun.  Nilai keberadaan ekosistem mangrove yang dinilai adalah Nilai Keaslian = 70 % (lebih dari asli), Nilai Keindahan Alam = 74 % (lebih dari indah), Nilai Kenyamanan = 66% (kondisi lebih dari nyaman),  dan Nilai Aspirasi masyarakat = 98 % (sangat didukung masyarakat). Alternatif  pengelolaan  dan  pemanfaatan  ekosistem  mangrove  yang diperkirakan cocok secara ekonomi dan ekologis terdiri dari beberapa kegiatan pilihan yaitu budidaya ikan, udang, tiram dan kepiting, budidaya ikan kerapu dan kakap, pengolahan buah dan daun mangrove, dan pengembangan obyek wisata.


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Syahrul Muharamsyah ◽  
M Sofwan Anwari ◽  
Hafiz Ardian

Mangrove forests are unique ecosystems that have ecological, biological and socio-economic functions. The function of mangrove forests on the environment is very important especially in the coastal and oceanic regions. Mangrove forests providers of wood, leaves as raw material for medicines, and natural dye. This study aims to inventory the diversity of species of mangrove vegetation in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency. The benefits of this study are to provide the data on mangrove forest vegetation as basic data for local government and related agencies in efforts to protect and preserve mangrove forests in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency. Inventory the tree in mangrove forest used a line with measured 200 meters. There are 6 lines and the distance between the lines as far as 100 meters. The lines of observation are placed by purposive sampling. The results of research found 11 types of species and consisted of 6 genera. The genera are Avicennia, Bruguiera, Ceriops, Rhizophora, Soneratia and Xylocarpus. The species found were Avicennia alba, Avicennia marina, Bruguiera cylindrica, Bruguiera gymnorrhiza, Bruguiera parviflora, Ceriops decandra, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, Sonneratia caseolaris, Xylocarpus mollucensis. Diversity of mangrove species in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency was high and should be maintained for conservation and ecotourism area. Keywords : conservation, ecotourism, mangrove, Mendalok Village


Author(s):  
M.S. Phalatsi ◽  
L.J. Fourie ◽  
I.G. Horak

The objective of this study was to determine certain aspects of the biology of Rhipicephalus (Boophilus) decoloratus larvae under laboratory and field conditions. Larvae allowed 48 h to select a vertical questing substrate preferred 90 cm rods in length to those of 60 or 30 cm, while in a separate experiment migration from rods 5 cm or 25 cm in length to rods 45 cm in length continued between 48 h and 72 h after larval release. Hatching of the larval progeny of engorged female ticks exposed to ambient field temperatures during the period June to August, occurred synchronously during the third or fourth week of November. With a single exception, larvae that hatched during November and between April and July survived for 38 days or longer, while those that hatched from December to March survived for 31 days or less. Questing larvae were present on vegetation throughout the year, with most being recovered during January and February. Parasitic larvae were present on cattle from October to May with most being collected during January and February.


2013 ◽  
Vol 40 (4) ◽  
pp. 400 ◽  
Author(s):  
Nadia S. Santini ◽  
Nele Schmitz ◽  
Vicki Bennion ◽  
Catherine E. Lovelock

Tree branches are important as they support the canopy, which controls photosynthetic carbon gain and determines ecological interactions such as competition with neighbours. Mangrove trees are subject to high wind speeds, strong tidal flows and waves that can damage their branches. The survival and establishment of mangroves partly depend on the structural and mechanical characteristics of their branches. In addition, mangroves are exposed to soils that vary in salinity. Highly saline conditions can increase the tension in the water column, imposing mechanical stresses on the xylem vessels. Here, we investigated how mechanical strength, assessed as the modulus of elasticity (MOE) and the modulus of rupture (MOR), and density relate to the anatomical characteristics of intact mangrove branches from southeast Queensland and whether the mechanical strength of branches varies among mangrove species. Mechanical strength was positively correlated with density of mangrove intact branches. Mechanical strength (MOE) varied among species, with Avicennia marina (Forssk.) Vierh. branches having the highest mechanical strength (2079 ± 176 MPa), and Rhizophora stylosa Griff. and Bruguiera gymnorrhiza (L.) Savigny ex Lam. and Poiret having the lowest mechanical strength (536.8 ± 39.2 MPa in R. stylosa and 554 ± 58.2 MPa in B. gymnorrhiza). High levels of mechanical strength were associated with reductions in xylem vessel lumen area, pith content and bark content, and positively associated with increases in fibre wall thickness. The associations between mechanical strength and anatomical characteristics in mangrove branches suggest trade-offs between mechanical strength and water supply, which are linked to tree growth and survival.


Flora ◽  
2010 ◽  
Vol 205 (5) ◽  
pp. 357-362 ◽  
Author(s):  
Gonasageran Naidoo ◽  
Yougasphree Naidoo ◽  
Premila Achar

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