VAI TRÒ CỦA HỆ SINH THÁI RỪNG NGẬP MẶN VÀ RẠN SAN HÔ
TheWZYXWVUTSRQPONMLKJIHGFEDCBA GEF TRONG S m all G rants P rogram m e DCBA VI~C G I A M NH~ THI~N T A l vA CAI THI~N cuOc S6N G Chu bien: Phan Nguyen Hong, t.e Xuan Tuan, v n ThI:lC iJ V U N G Hien V E N B IE N T ru n g ta m N g h iE m cuu H $ s in h th a i D Q i h Q C S u p h c rn Rung ng¢p m en (M E R e ) H e N Q i ( H N U E ) DCBA V a i tsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA tro cua he s i n h t h a i r i r n g ngap man va ran san ho viec giam nhe thien tr o n g va cai thien cuoc son g a vung ven bien Chu bien G S TSKH Phon TS Le xucn N guyen Hong Iu d n T h S V u T h u c H ie n Co quan tai trQ Chuang tr in h ta i tr o c c c Q u y M i tr u o n g T r u n g ta m N g h ie n cuu Nh6 xudt du an nho Icon cou (G E F S G P ) H $ s in h th a i r u n g n g ¢ p ban N6ng H6 NQ i - 2007 n g h i$ p m en ta i .• tsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA : Myc luc Trang Danh luc bang, phu luc, hlnh va anh v Chu v ie r tat xviii Lei noi dau xx earn on xxiii U1i Danh sach nhirng nguoi tham gia viet bai xxiv Phan 1: Vai tro cua cac h~ sinh thai rlIng ng*p man va ran san h6 vi~c giam nh~ tac dong cua dai duong - Kinh nghiern qu6c te va Vi~t Nam Dac diem hlnh cac loai song Ion ven bo Viet Nam va tac dong cua rung ngap man lam giam nhe thien taikjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Blli Xuan Thong Vai trc>chan song baa v~ bo bitin cua rung ngap man Viet Nam Yoshiliiro Mazda, Michimasa Magi, Michimasa Magi, Motohiko Kogo, Phan Nguyen Hong Yoshichika Ikeda, Mazda, Faizal Parish, Kurokawa, Tetsumi Asano 33 Finn Danielsen, Fumihiko Imamura Bien dong ran san ho vung bien vinh Bac BQ va nhirng van de rnoi tnrong co lien quan Nguyh: Huy Hong, va TIt(IC DCBA H ie n , Le Xuan Tudn, Nguyen Vai tro cua rung ngap man viec giam tac dong cua dai a Thai Nguyen 57 Hiiu Tho, Vii Doan Thai d ir c n g Lan Buocdau Vai Sanit Aksornkoae ~a cua Vii Doan Tha! 71 77 cac he sinh thai viec baa ve be bien, cuoc song va sinh lee cua cong d6ng: Bai hoc tu song than Chau A 10 den rnoi tnrong nghien ciru leba nang chan song, baa ve lX1 bien baa qua mot so kitiu eau true rung ngap man ven bitin Hai Phong 49 yet Vai tro cua rung ngap man viec baa ve cac vung ven bitin Phon 1/ 21 Tadayuki Rung ngap man - Tam la chan baa ve can nguoi chong lai song than Yoshihiro bang Bac BQ, Su giarn song rung ngap n1~ co loai ban uu the Yoshihiro Mazda, a dong Gayathri Rung ngap man ven bien giarn nhe song than 11 Nhirng van de moi tnrong ven bitin n6i bat a Viet Sriskanthan K Kathiresan, N Rajendran Nam va dinh huang baa v~ 89 1/1 1/9 Trail Due Thanli 12 Tfch tu cacbon dilt rung ngap man tai mot so khu rung Nguyell Thallh no, R Yoneda, I Ninomiya, Ko Harada, a Nam D Y Tall, M.S Tudn, Dinh· 135 P N Hong 13 Sl! tich tu cacbon va nito mau phan huy IU ruroc bien dang cao, gay chet nhieu loai sinh vat d6 c6 san ho Trang EI-Nino 1997-1998, nhiet d(> ruroc bien tang trung blnh ,8oC (Dieu va cs 2000) Ke tir narn 1982 den nay, c6 12 nam EI-Nino, Nino 1982-1983 va 1997-1998 d6 El- duoc coi la manh nhat the ky 20 La Nina, thirong xay sau EI Nino, gay rmra 1i11OOlam ngap lut, due hoa, ngot hoa ruroc ven bien, x6i la bo bien va ci'ra song rnanh Tir dllu thap ky 70 den nay, La Nina xuat hien 5111n (Hi~n 2001), thuong kern then nhieu bao hon, d6 b(> nhieu van Nam Trung B(>van cac thang cuoi nam Xu the chung la so hrong bao va ap thap nhiet doi (ATND) d6 b(> van vung bo Viet Nam tang then thai gian Trang thai gian 1975-1994, trung blnh moi nam c6 2,5 can bao va 2,2 ATND d6 bo vao, nam 1996 c6 toi can bao, ATND d6 b(>vao Phan bo rrura bao thay d6i va tfnh bat thirong tang len, Hen rmroi nam qua, bao d6 be van ven bien Bac B(> giam h~n, bao a Trung B(> tang len va dich v~ phia nam Bao Linda d6 bo van Nam B(> van cuoi narn 1997100 bat thirong va hiem gap theky 20 Rieng thang 11 nam 1999, c6 toi can bao d6 bo lien tiep van ven bien Trung B(> Luong mira ven bien nhln chung giam, nhung luong rrura Thien-Hue a a Thira a Hue dat nhieu khu vue tang dang ke Vi du, hrong rrura trung binh nhieu nam 3000mm, rieng nam 1999 la 5642mm, d6 c6 hrong rmra 24 gio 1384mm (Viet va Hung 2001) Nhfrng van nhiern de moi truong yen bo nbi bat moi truong Chat lirong ruroc ven bien Viet Nam can kha tot, mac du nhiem biln mot so chat da ducc ghi nhan a mot so noi (H6i va cs 2001).6 a rrurc khac a cac nhiern dau nghiern nhat vung ruroc sat bo, ham hrong thirong vuot rmrc cho phep 0,05 mg/! doi voi thuy san va khong It noi virot mire cho phep 0,3 mg/I cho noi tarn bien 0,05 mg/!, cue dai 0,4 mg/! ghi nhan duoc a 10% vue khai thac dau va tren tuyen hang hai qucc 0,34 mg/I van cac narn 1997-1998 te o vung ngoai khoi, ham hrong dllu tren so tram van tnroc nam 1996, cao nhat a khu Ham luong dau ruroc bien trung blnh (Dieu va cs 2000), gan day tiep rue tang Nhiem biln kim Ioai nang nhir Fe, Cu, Zn, Cd, As, Pb chua rong nhirng bieu hien tap trung va tang rnroc, tram tfch va co the sinh vat nhiem Fe, Zn, Cu xuat hien o nhiern kern kha phd bien vao 1996-1998 a vung so noi, (Dieu va cs 2000) Niroc va tram tich cac khu khai mo va che bien khoang san thirong nhiern dong, thuy ngan va chat ph6ng xa 122 a mot bien Viet Nam (Ninh va cs 2005), ham luong 5,30-53,80g/! Nhiing va'nZYXWVUTSRQPONMLKJIHGFEDCBA d e moi tnrong yen bien n6i batDCBA a Viet Nam va dinh huang bao v~ Xyanua moi tnrong bien rat nguy hai co doc tfnh rat cao, co the tach chiet a vangkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA cac mo sa khoang va su dung gay me danh bat hai sari Nam 1999, ham lueng xyanua (CN-) trung binh a mien Ll Ian, a cac tram quan trilc ven bien mien Bac Trung 1,4 Lan va a mien VU91 qua gioi han cho phep Nam 1,5 Ian Ham hrong xyanua ruroc bien rat cao thay a 50% s6 rnau a C6n Co, 100% s6 rnau a Con Dao vuot gioi han cho phep Dac biet a Bach Long Vy, 100% s6 mAu virot gioi han cho phep tu - 22 Ian Nhiing nam gan day, ham hrong xyanua rnoi tnrong ven bien giam h~, phan Ion duoi rrurc cho phep Noi chung, dir luong hoa chat bao ve thirc vat dum rrurc cho phep, mac du bieu hien tich lfiy kha phd bien va dii th6 song Hong (Cu 1998) VU91 cac qua gioi han cho phep tai mot s6 diem, VI du ven bien chau tram quan trac ven bien mien Bac, du luong hoa chat bao ve thuc vat nam 1999, chua qua gioi han cho phep nhung tang 25 Lan so voi nam 1998 nhiem coliform chat h fr u co mang tinh cue bo, nhung tap trung kha cao ruroc ven bien thirong cao va VU91 mire cho phep a gan a mot s6 diem Chi s6 cac khu dong dan cu, du lich nhu Cira Ll;IC, Sam Son, Nha Trang va Vfing Tau Ham luong cac chat dinh duong photphat (P04-3), amonium (NH4+), nitrit (N02 -), nitrat (N03 -) dii virot qua gioi han cho mot s6 tram quan trac Phii dirong (du thira chat phep tir mot vai Mn vai chuc phan tram a dinh dirong mroc) La van d6 moi tnrong n6i bat a phia Nam chat dinh duong va v~t chat hiru co phat thai tir nguon sinh hoat, nong nghiep va nuoi tr6ng thuy sari Dii xuat hien cac nii ro nuoi thuy san niroc lo 1994, nghe nuoi tom mroc lo a phfa a ven Nam lien quan Mn phu duong va thuy trieu Nam bien chau th6 song Me Kong thiet hai Mn hang nghin ti dong dich benh Hien nrong "no hoa" cua loai tao silic Skeletonerna costa turn a D6 Son vao thang 8/1999 La dau hieu cua hien nrong phii duong Gan day nhat, vao thang 11 nam 2002, thuy trieu dii bung phat tai vung ven bien Nam Trung B¢ (Khanh Hoa, Binh Thuan) tren dien rong, gay thiet hai Ion v6 kinh t€ va rnoi tnrong.DCBA M at noi song va suy giam tal nguyen s in h hoc Cac he sinh thai ven bien bi suy thoai ngot hoa, due, phu dueng, nhiem bAn, mat noi cu tni, Lam giarn nang suat sinh h9C va da dang sinh h9C Bien dong khf hau va nhan tac Lam mat noi cu tni ven bien nhu cac bai trieu, RNM, bai bien, tham co bien va ran san ho, RUng ngap man bi huy hoai nang n6 chien tranh, khai hoang nong nghiep, nuoi thuy san, xay dung cac khu dinh cu va ell xoi La bo bien nhu a Dong Bilc Bac B¢ va Dong Nam ban dao Ca Mau Nam 250.000ha 1943, ell ruroc co 408.500ha a chau th6 Me Kong 155.000ha (Ninh va cs 2005) rirng ngap man, rieng (Hong and San 1993), nam 2000 chi khoang Dien tfch bai trieu giarn rnanh xoi La va khai thac cat Cac ran san ho va tham co bien bi huy hoai bun due, ngot hoa, song bao, nhiem ban va cac hoat dong khai thac huy diet nhu cao xoi nen day, dung thu6c n6, hoa chat khai thac thuy san, Ca mroc hien co khoang tren 1000km2 ran san ho, t~p trung a ven bien Trung B¢ va vimg bien TmOOg Sa, Hoang Sa Thai gian qua d¢ phu cac ran san ho giam rat nhanh Trong EL Nino 1997-1998, dii xuat hien a mot s6 noi, dien hlnh a Bach san ho chet trang Long Vy T