^fii pja ly va T i i nguyen Mfii truong Thfia Thien Hug Hoi Dia ly Viet Nam
Ru'ng ngap man va da dang loai cua rCrng ngap man dam Thj Nai kliu vyc Tp. Quy Nlian, tinli Binh Djnh tru'O'c nguy ccc anh hu'ang
cua bi6n d6i khi hau
Luong Thi Van', Nguyen Thj H u y c n \ Phan Thai Le^
Abstract
The risks and impacts of climate change to mangrove forests and biodiversity of mangrove of Thinai lagoon in Quynhon city, Binhdinh province
Thinai lagoon in Quynhon city is the largest lagoon of Binhdinh province and the .second largest of lagoon system in our country. Ecology of mangroves in there is s'ery characteristic with riches and diversity of plant species For the reasons of natural, economic - social, the mangrove and diversity of species in there have lossen significant Due lo Ihe impact of climate change, the decline of biodiversity and ihe disappearance of many species will be great. Based on the research of works and documents previously, the authors have the number's studies of. such as additional invesiigalion and analysis of natural conditions, status and causes of decline in mangrove forests and the mangrove's biodiversity in Thinai lagoons, analysis of the effects of climate change to the mangrove and il's species diversity, invesligale the vulnerabdity of communilies along ihis lagoon area From this, the authors have recommendations for solutions developmeni, conservation and mangrove and mangrove's htodiverstly of Thinai lagoon in Quynhon
LDATVANDE
Quy Nhan, Tp. tinh ly cita tinh Binh Djnh cd 42 km dudng bd bicn, nai da tiing cd ca 1000 ha dien tich rimg ngap man (RNM), 200 ha thim cd bicn... vdi tinh da dang sinh hoc (DDSI i) rat cao vi li mQl Irong nhirng que huong ciia mpl sd loai dac sin quy, cd gii tri kinh Ic cao va gii Iri ngudn gicn ddc dao. Cic he sinh thii (HST) niy da tao dieu kien thuin lgi cho ning suit va tinh giau cd ve da dang cic loai Ihude ihiiy vuc dim hd ven bicn, duy tri su dn dinh vc mdi irudng cho su phit trien hai hda ciia cac loai thiiy sinh va cgng ddng din cu sdng ven dim, nhit li dam Thi Nai, nai tap trung RNM chu yeu eua Tp. Quy Nhon va viing lan can. Tuy nhien. trong nhicu nam gin diy, do khai thic qui mire lim dicn tich RNM bj suy giam, ngudn Igi sinh vat RNM bj can kiet din. Cho den nay, RNM Iheo dung nghia mdt HST da bien mit va chi edn lai nhirng dii cay ngap man phan bd rai ric d mgt sd nai. Die biet, trong xu the ciia bien ddi kin' hiu (BDKH) dang dien ra hicn nay se gop phan diy nhanh su suy giam ve sd lugng vachit lugng RNM ciia khu vuc dim, dinh mat nhirng vai trd, chuc nang kinh Id, sinh thii quan trgng va to Idn ciia chung. Theo kk hoach DDSH qudc gia, cic dja phuang can dac bict quan lam den eic giai phap u:ng phd phii hgp vdi cic kich bin ciia BDKH dc trudc het bao ve vi duy tri DDSH trong cac HST ndng lam nghiep, quy hoach vaquin ly ben vung cic viing dit thip va RNM [1].
Do viy, nghien cuu "Rirng nggp mim vd da dgng cdc loiii riing nggp nu'tn diim Thi Nai khu vuc Tp. Quy Nhan, ttnh Binh Dinh trudc nguy cir dnh hirdng cua bien ddi khi hgu" li vice lam cd y nghia ca ve mat khoa hgc va thuc tien, gdp phin hoin thien co sd khoa bgc cho bio ton RNM vi DDSH - RNM Viet Nam ndi chung va d Binh Djnh ndi ricng; ddng thdi tham gia bao vc mdi trudng (BVMT) va phit trien ben virng cho Tp. Quy Nhon.
Khoa Dia li - Dia chinh. Trudng Dgi hgc Quy Nhan
DIA LY TU'NHIEN. TAI NGUYEN THIEN NHIEN VA MOI T R U 6 N G
Hoi Dia ly v i T a i nguyen Moi t r u i n g Thua Thicn Hue Hgi Dia ly ViOl NflB
Tren co sd he ihong hda cic cdng Irinh, lii lieu cd trudc, nhdm tic gii da dicu tra bd sung, p\^^
tich DKT>J, thuc irang, nguyen nhin suy giim RNM vaDDSIl - RNM dim Thi Nai; Phan lichngm ca anh hudng cua BDKH ddn RNM va da dang cic loii RNM eiia Miu vuc dim; Dicu ira tinh d^b ldn Ihuong ciia cdng ddng din cu khu vuc ven dam. Tir do, de xuit djnh hudng cic giii phip pijj tridn, bao tdn RNM vi DDSH - RNM dim Thi Nai khu vuc Tp. Quy Nhcm.
2. GIOI TIHFU KHAI QUAT DAM THI NAI VA DA DANG CAC I OAI RNM DAM TUI NAJ 2.L Gidi thicu khai q u i t ve dam Thi Nai
2.1.1. Vi tri dia ti dam Thj Nai
Dim Thj Nai nim Irong khoing 13''44' - 13°55-VBva 109''l4;- 109''l8'KD, la dim mrdc lg J man lunhicn ven bien, nim vc phia Ddng Bic eiia Tp. Quy Nhan. Dam cd chicu dii khoang 15 kiiivai rdng 4 km, phin bd theo chidu Bic Nam. Dicn tich dim rdng ban 5.060 ha liic trieu len vi klioang 3200 ha hie irieu xuong. Vj tri ciia dim nam lgi thdm trong mdt eo bicn nhd, an ngu bdi IKU: dao Phuang Mai vi Ihdng ra bidn bdi eo bicn Cua Gia rdng khoang 500 mel. Vc phia Tiy vi Liv Hac, dim tidp giap vdi cac phirang: Nhaii Binh, Dong Da, Thi Nai, Hai Cang cua Tp. Quy Nhan vi cic xa Phudc Thuin. Phudc Son. Phudc Hda ciia huj'cn Tuy P h u a c ; Vc phia Uong, dSm titp giap vai xa Nhon Iloi va Mai Cang.
Dam Thj Nai va bin dao Phiroiig Mai limg la vj tri phdng thit chicn luge quin sir quan Irgng, la nai ghi dau nhicu cliien cdng hicn liach cua nghia quin Ta\' Son, Ihcm vao dd con \e dcp lu nhien eua RNM Ngiy nay, dim edn dus'c noi bit ban bdi ci\ can Thj Nat (Ciu Nhon I loi), cau vuat bicn dai nhat Vict Nam, ndi Iicn ban dao Phuong Mai \ dt Tp Quy Nhon.
Din. lhi Nai ndi lidng vi la danl I6ij nhit tinh Binh Djnh vi Idn thu hai trong he thon|
dim phi cua ca nude sau dim pha Ciu Hai - Tam Giang (Thira Thicn - Hud). Dim Thj Nai cd IIST - RNM die trung vdi nhieu gidng loai dgng thm vat da dang, giau cd.
2.1.2. Dac dicm Iu nhicn kliu virc dam Thi Nai
* Dja ehat, dja hinh, tho nhudng Dja hinh dim Thj Nai nim Igt Ihdm trong mdt eo biln gin nhu khep kin. Khu vuc dim dugc ciu tao bdi tram tich holoxen dat boi, bao gdm cac vat lieu hat min ed ngudn gdc sdng, b'^"
tao thanh dim lay li set, cat, mim thue vat, phSii' bd dgc xung quanh dam va cic cdn ndi, go ba' cao trong dam vdi do cao trung binh cac con, go bai niy chi hoti mat nudc khoang tir 1,5 - 2 met-
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Hdi nghi Khoa hoc Dia ly Todn quoc Idn lhu 6; Thdnh pho Hue, 9/20H 542
ugi pialy va Tai nguyen Moi truong Thiia Thicn Hue _ ^ _ ^ _ ^ ^ Hoi Dja ly Vict Nam fjjd nhudng ctia khu vuc phan ldn la dit man, dit man sii - vet vi dit man it
* Khi hau, thuy hii vin
- Khi hau: Khu vue dam Thj Nai mang dac diem ehung ciia khi hau Tp. Quy Nhon: Nhict ddi jffi gid miia Nam Trung bd, anh hudng true ticp vi rd net cua bicn. Nhict dd trung binh nam 26,7''C, nhiet do trung binh thing cao nhit 29,7 C, nhicl dp trung binh thing thip nhat 23,1°C, nhiet dg cao tuyet ddi la39,9''C va thip tuyet ddi 15 C. Dao ddng nhict do giiia cic thing vi trong nam khdng ldn, nSng ndng gin nhu quanh nam, tdng sd gid nang Irung binh >2000 gid/nam. Miia khd keo dai, trimg vdimuanangndng tir thing I den thing 8. Miia mua ngin (lir thing 9 den thing 12) nhung chicm 75 - 80% Iirgng mua ci nam, tap trung Idn nhit vao Ihang 10 \ i 11. Lugng mua trung binh hing nim 1677mm. Che dg gid ciing the hien theo miia rd ret. Mua ddng, gid Bac va Ddng Bac, tdc dp gid trung binh l,8in/s; manh nhat vio thing 12, dat 2,8m/s. Gid miia Ddng Bac thdi dge dii ven bicn va vimg dam Thj Nai gdp phin lam ha thip ncn nhiet do Miia he cd gid Ddng Nam vi Nam. Tdc do gid trung binh 1,3 - 1,7 m/s. Cie thing 7, 8 cd gid Tiy vi Tiy Nam, tdc do gid kha cao, thdi manh ihco tirng dot kho ndng, nhiet do khdng khi cd the vugt >37''C, cd khi dal 39 - 40"C, do im tuong ddi giim nhanh.
chi cdn khoang 50% va cd the xudng cdn 25 - 30% [2], khdng khi khd rio. bdc hoi manh, gay linh tr^ng thicu nudc gay git, anh hudng rat ldn den sin xuil va ddi sdng cua ngudi din trong vi'ing.
Quy Nhon cdn chju anh hudng true liep hoac giin tiep cic con bao vi ip thip nhicl ddi lir bien Dong. Trung binh cd khoang 1,04 con bio dd bd vio khu vuc, nhieu nhit vao thing 9 - 11. Cd nam b3o sdm vio thing 6 hoac mudn vao thing 12. Miia bao thudng xiy ra trimg vdi thdi ky hoal dgng ciia gio ddng bie. dii hdi lu nhicl ddi, ap thip nhiet ddi vi cic hinh the thdi licl khic gay ra cac dgi mua lii Ion, ngip lut liu dii, nhit la nhung viing ven bien vi vitng dim Thi Nai
- Ddng chiy sdng ngoi. Khu vuc dam Thj Nai chju su chi phdi vi inh hirdng ciia hai he thdng song chinh thugc tinh Binh Dinh la sdng Kdn vi sdng Ha Thanh. Cac nhanh ciia hai sdng niy deu chiy vao dam trudc khi dd nude ra bicn. Cic sdng niy deu ngan, ddc, cd lugng phii sa luong ddi. Do che phit ciia rung tu nhicn cua luu vuc den nay khdng cdn nhieu (30 - 32%) ncn hang nam cic sdng niy thucmg gay ra 10 lyt, sa bdi, thuy phi nghiem trgng vio miia mua khien cho dim mdi ngiy mdt diy them. Ngugc l?i, vio miia klid, nudc cac sdng can kict, thieu nudc trim trgng. Chenh lech giiJa luu luong lii va luu Iirgng ki?t ddn tren 1.000 lin [2].
Dim Thj Nai cdn cd quan he vdi hd nudc tu nhicn Phii Hda, rdng 80ha. Ild thdng ra ditn Thj N^ii qua cac nhinh phia Nam eua sdng Ha Thanh.
- Thuy trieu: Khu vuc dim Thj Nai cd che do ban nhal trieu khdng deu, tuong lu nhu d vimg bien Binh Djnh. Thdi gian Irong Ihing cd khoing 20 ngay nhit tridu. Bicn do trung binh ciia thiiy itm. 1,2 - 2,2 met, nude rdng cd bien do 0,5 - Im. Thdi gian trieu ding dii han ihdi gian trieu riit.
Trong thdi ky miia mua, do lugng nudc mua trimg vdi bien do ciia trieu cuong nen cd the chenh lech 0|4 - 0,6 met. Tinh ehit eua thity trieu da inh hudng rat Idn trong viec hinh thinh vi phit trien cac he sinh thii viing trieu, RNM vi eic khu he sinh vat ven bd.
- Nhiet do nudc vi do man: Chju anh hudng manh ciia gid miia va thay ddi theo cic thing trong nim. Vao cac thing 7 vi 8, nhiet do nudc ciia dam Thj Nai tang Ien Iir 30''C - 32"C, Ihip nhit vao cac tog 1 vi 2, tir 25''C - 27''C. Dd man trung binh cita dam dao dgng ldn, trung binh tir 5 - 32''/oo. Q viing ven dam, do man thap hem va bien thien khi phire tap do phu thudc vio lugng nudc nggt lir sdng hodd ra. Trong nhirng ngay mua Idn giy lu lut, do man nudc khu vuc dam cd the giim ihip dudi 5"/oo- Ngugc lai vao thdi gian hoat ddng ciia gid Tiy Nam khd ndng, nudc bicn bdc hoi manh lim dd man ting ding kd, dac biet li thing 6 - 8 (28 - 33%o).
0|A LY TU NHIEN. TAI NGUYEN THIEN NIIIEN VA MOI TRUONG
Hgi Oja ly va Tii nguyen Moi truong Thiia Thicn Hue Hoi Dja ly \^^f 2.2. Riing ngap man va tia dang cac loai riing ngap man dam Thi Nai
Dim Thi Nai cd 185 ioai thuc vit ndi thupc 54 chi, 5 nganh tao, vii chiic loii rong. Cd khoi|j 72 loai thuc vil phii du, Irong dd cd 20 loai tio hai roi, 49 loai tao silic, 2 loii tao luc vi 1 loaj')^
xanh lam [5]. Ricng Ihanh phan cay ngap man co dii cic loai dac Irung nhu dude, dung, dung, v^i mim quan, mini den, mim tring, gia, sii, trang, ban ehua, dira nuac,.... HST - RNM nguyen sinli rgi^
ci 1000 ha trudc day ciing vdi dien tich thim cd bicn vi vimg day mem rdng hing tram ha khac Jatji dieu kien thuan Igi cho viec cu tru, nuoi dudng, kiem in, sinh sin cua nhieu loat thiiy sinh vfit vaicJi triic quan xa sinh vat Ihudng thay ddi theo miia. Da xic djnh dugc 25 loii cay ngap man phan boi Cdn Chim \ i cac vitng lan can trong dim, trong do cd 18 loii cay ngap man ihue sir (true mangrove vi 7 loii ciy Iham gia RNM (associated mangrove) [5]
Khu vuc dim Thi Nai cdn cd khoing 64 loii dgng vat phii du, 76 loii ci ihugc 40 hg, chti yeu 1 cic loai ven bd nhiet ddi cd kich thudc trung binh vi nhd, thinh phin loii bao gdm cic nhdm loi nudc man, nhdm loai nude lg vi nhdm loai nudc nggt - Ig, nhieu nhit li ea ddi, ca bdng, ca liei, ( cam An Dd, ca com thudng, cac nhdng van, ci chio, ci dua, eac mdm, ci gid...
Bdng 1. sd luang lodi thuc ddng vdt RNM ciia ddm Thi Ngi Tliirtu-
1 2 3 4 5 6 7 8 9 10
Ten Thirc vat phu du Rong Dong vat phii ciu Dong vat day Dong vat than mem Tom
Ca Cua Ghe Chim
So liro'ng loai | 85
136 64 181 100 14 119
2 3
36 1 Nguon f5]
RNM dam Thj Nai cdn cd nhicu loai chim. tap trung ddng diic nhat d Cdn Chim, gdmcacSc loii chim nudc vi chim bd bicn di cu. Tdng cpng cd 33 loai, trong dd cd 23 loii chim nudc va 10 loat chim riing Ihugc nhidu bd, ho khac nhau nhu bd si, bd bd cau, bg se... Sd lugng c i the ciia mpl so loai tuong ddi ldn nhu diec xim, vac den, nhan niu, choat, cd va mdt sd loai choi choi, mgt sd loii thugc hg vjt, hg cdc. Tai day cdn cd ca rii ci vi cd thia li loii chim rat quy hiem cd ten trong SachDd Vi|t, Natn va Sach Dd the gidi. Khu vuc nay cdn la nai kiem an ciia chim yen hing vi yen nii - la cac loai chim rat quy hiem cd gii tri ve kinh te, khoa hgc y hgc,
Ben canh dd, dim Thi Nai cdn cd iham cd bien rdng gin 200 ha vdi cac loii chicm iru tlie la ZosterCi Japonica va Halodule uninervis. Do phii cita thim cb Zostera japonica Aao6Qn%\.isSf)' \w%
mat dd cay tir 3.000 - 5.000 cay/m^ Do phu ciia thim cd Halodule uninervis tir 20 - 60%, mat dgtir 350 - 1.500 eiy/m^; cd khoing 10 loii ed bicn kich thudc Idn nhu rong lam, rong luc, rong do, rong ciu,,. Viing niy da xic djnh dugc 134 loai dpng vai khdng xuong sdng thugc 50 hg vi 5 nhdm ngan"- Trong do, Idp giun nhicu to cd 34 loii thugc 17 hg, than mem ed 100 loai thugc 67 gidng, 43 hg, 8 m nam trong hai ldp; giap xic cd 35 loai thugc 16 hg, da gai cd I Ioai, nhdm khic gdm 4 loai thupc 3 nQ' Cic loai than mem tieu bieu cd vem cd xanh, hau sira, sia niu, xia lua, ngao, ph^nh...; mdt so loaicc gia tri kinh te cao va cd san lugng cao, cd kich thudc Idn nhu tdm su, torn bac the, tdm rao dat...
Hgi nghi Khoa hoc Dia ly Todn qudc ldn thd 6; Thdnh pho Hue, 9l2vl-
flBiPia ly va Tai nguyen Moi truong Thira Thicn Hu£ Hoi Dja ly Vict Nam
Ngoii ra, vimg diy mdm cua dam cijng cd dien tich Idn, khoing hon 300 ha da tao mdi trudng cho sir phong phii ciia cac loai than mem, giip xic ven bd. Nai diy khdng chi cd tinh DDSH cao vd cSc loai Ihuy sin sdng di chuyen nhu ca, tdm, cua ma cdn li nai phan td quan trgng ciia cic ngudn giong ca, giip xic, thin mdm. Ngudn gidng giap xic trung binh la 440 ca the/m^ giong chii yeu la au (fiing cua vdi mat do trung binh dat 285 ca the/100 m^ chi^m 64,83% ldng sd nguon gidng. Nguon giing than mem eung khi cao, mat dg trung binh vio miia khd dat 3.809 ci thd/m^ thinh phin ehu yeu thudc ve nhdm hai minh vd.
Ngudn Igi thiiy sin dim Thj Nai rat phong phit vi cd gii trj, dugc nhan dan dja phuang khai thac g^ nhu quanh nam vdi sin lugng Idn. San lugng ei khai thic hing nam trung binh tir 7 - 12 tin, chii y^u cac loai ca ddi, ca bdng, ca liet, cic mdm, ea gid...Cic loai giip xic nhu tdm, cua, ghe ed sin lugng (j^t 75 tan/nam. Cac loai thin mdm nhu ngheu, sd, sia nau, vem cd xanh, hau trdn, hau mudng, di^p.-cung dal 1.200 tan/nam.
3. SVSUY GIAM RNM VA DDSH - RNM DAM THI NAI TRU"6c TAC DQNG CUA BDKH 3.1. Sir suy giam RNM va DDSH - RNM dam Thi nai
3.1.1. Tinh hinh suy giam RNM va DDSH - RNM dam Thi nai
Mac dau, dam Thj nai trudc day cd dien tich RNM vi DDSH - RNM rit giiu cd va phong phu nhu da ndi tren, nhung do hau qua chien tranh vi nhieu nguyen nhan khic nhau da lam dicn tich RNM va DDSH - RNM bj giim sut mgt each nhanh chdng vi nghiem trgng.
Nhirtig nam 40, 50 ciia thd ky trudc, toan bd dicn tich dim Thj Nai vi khu vuc cdn Chim ndi chung vi dgc theo bd phia tiy ciia dim thudc xa Phudc Son, Phudc Thuin, RNM phii triin rit m^nh me va sam uat ddn ca 1000 ha, vdi nhieu cay ngap man phong phu vi die trung, than cay eao Idn, mil do cay day die, tao nen can cir dja thuan lgi eho hoat ddng cich mang trong thdi ky chdng Phap vi chong My ciia nhan dan ta. Den nam 1975, mac diu do chien tranh tin phi, nhung RNM trong dim
•van cdn bao phii day die khoang hon 350 ha. Den nim 1985, RNM giim xuong cdn hon 200 ha vi hien nay, chi edn khoang hon 50 ha RNM tu nhien tai sinh Cac khu RNM cd dien tich rgng ldn ven khu vuc dim dudng nhu khdng cdn niJa, thay vao dd li nhung ao, dia nudi thuy sin; chi cdn lai nhirng dai, rang ciy ngip man nhd hep, chu ylu li cac cay dude, trang, ban phan bd rit thua thdt, dpc theo cac bd bao ciia cac ao nudi trdng thuy san hoac dgc theo bd dia nudi tdm va tren eic viing dit cao cd di|ntich rit nhd d viing cdn Chim hoac dgc theo bd lay ciia xa Phudc Scm la chinh [10].
Hien lai, dien ti'ch quy hoach trdng RNM dam Thj N^i cd gin 170 ha; trong dd huyen Tuy Phirdc chi^m gin 150 ha, Tp. Quy Nhan 20 ha. Tuy viy, den nay dien tich RNM da dugc trdng chi niot d^t 13 ha, trong do Tp. Quy Nhcm trdng 10 ha, edn huyen Tuy Phudc chi cd 3 ha.
Dien tich RNM rgng ldn bj mat di da keo theo su suy giim cic khu he ddng thuc vat, DDSH va ngudn lgi thuy sin d dam Thi Nai. Phan ldn dien tich RNM hien nay cd thinh phin loai cay tuong ddi
^Ong nhat, chiem da sd trong dd li dude, ban..., mat do mgc khdng diy die. Mat khac, sin lugng mpt so loai Ihiy sin dac trung nhu ca cam An Do, ci nhdng van, ci chem, ci chao,... giim sut manh. Cac loai than mem hai minh giam 67%; tdm giim 65%; ca giim 47%; cua giim 55%, ghe giim 35% , loii Co thia gan nhu mat han, loii rai ca thinh thoang mdi xuat hicn, loii choai choai, choit, mdt sd loai ftuOc hg vit, hg cdc va chim yen hang, chim yen mii ciing xuat hi^n rat it va thua thdt...
B[A LY TU' NHIEN, TAI NGUYEN THIEN NHIEN VA MOI TRU'CJNG
Hfii Oja ly va Tai nguyen Moi trudng Thiia Thign Hud Hui Dja ly VielJNan, Bdng 2. sd luang cd thi mdt sd lodi chim khu v^rc cdn Chim. ddm Thj Nai
TT 2 7.
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Ten loai
Co trang Dice xim O c a Choat chan h6ng Choat 16n Choat dom den Re limg den Re khoang Choi choi Nhan Nhan den Yen hang Chia vol trang C6 thia Co xanh Niec nau Mi^c CO hung
So luong ca th6 5/1/03 15 168 1 40 89 37 24 3 15 10 8 7 1 2
23/3/03 33 90 12 8
3 2/04
Chi cliu 1
T (SDVN) R (SDTG) T ( S D V N ) T(SDVN) (R) Lodi quy hiim, (T): Lodi bi de doa; Ngudn [5]
3.2.2. Nguyen nhan suy giam RNM va DDSH ~ RNM dSm Thi Nai
* Nguyen nhan KT - XH
Nguyen nhan dau lien ciia su mit RNM la do chien tranh, cdn lai chii yeu li do tinh hinh .\a lipi sau ngiy giai phdng, sd ngudi dan tan cu vao ngi thinh Tp. Quy Nhon quay ve khu vuc ven dam la noi cu trii cii de phat trien sinh ki gin lidn vdi ngudn lgi thuy sin noi day. Nhieu di?n tich RNM bj : chit phi de liy dat lam nhi eda, lay gd lim chit ddt, lam chdi canh, xiy dung ao, hd, dia nudi thity san tdm ca, phat tridn ndng nghiep, xiy dung dudng sa,,..D3c biet phong trao nudi trdng thiiy san t^i dja phuong phat triin manh khien cho gin toin bd dien tich RNM bj phi hiiy mgt cich nhanh chdng ya ngudn nudc dim bj d nhiem. Trong thai ky miia khd, d nhiem mdi trudng dam Thi Nai cdn do nhifia ngudn thii tir eic hoat dgng phat trien va dd thj hda cita cic phudng Nhan Binh, Ddng Da, Thi N^i, Hii Cing,...ciing vdi sire ep cua khu kinh td Nhon Hgi cd dien tich rgng 12.000 ha, trong do, cd khu cdng nghiep Nhon Hgi rgng 1.395 ha dugc hinh thinh tir nam 2006. Mat khac, do y thire eua ngir&i din vi tap quan sinh ho^t lae hau, mat ve sinh, phdng ue bira bai, giy nen tinh trang 6 nhicm moi trudng khu vue dam tram trgng [10].
Mit RNM, cgng them vdi su khai thie ngudn lgi thiiy sin qua mijc, hinh thirc khai thae mang tinh hiiy diet "hu ra dien, xiet dien, gia cao, diing thudc nd... da lam cho ngudn lgi sinh vat khu virc bl suy giam nghiem trgng, cac loii tdm, eua, ca, nhieu loai chim nude bin dja hoac di cu tdi theo mua da giim manh, su xuat hien tap trung theo kieu tap doan cac Ioai chim theo ciing bj giam han.
* Nguyen nhan tu nhien vi BDKH
BDKH da gay ra nhieu hien tugng thdi tiet bit thudng: Nhiet do tang, gid bao, muc NBD, inc"
cudng, lu lui, lu quet,... klidng theo quy luat nen rat khd du bao trudc. I lien lugng xam thuc cita th'jy triiu ngiy cang tang, nhiet dg im len tren loan cau vi nhii'ng bien ddi that thudng ciia Ihdi tiet, khi hau lam anh hudng den tdc dp phat trien RNM vi DDSH - RNM eiing vdi eic ngudn lgi thuy san cua RNM.
546 Hgi nghi Khoa hgc Dfa ly Todn qudc ldn thir 6; Thdnh phd Hui 9/20H
f Ilgi pja ly va Tai nguyen Moi truong Thira Thicn Hue Hoi Dja ly Viel Nam ]s|hi?l do tang ISn, su tieu thu qui miic ciia cic loii thuc vat thiiy sinh hoac qui trinh phan hgp chit hiru go lam him lugng oxy trong nudc giim manh, inh hudng den su sinh trirdng vi phit tridn ciia cac loai y nhien va loai sinh vat nudi: Tdm, cua, ci cd the bj chet hoac chim ldn, sin lugng giim. Nhiet do ling cao la dieu kien thuan Igi eho sir phii trien cua cie loii vi sinh vat gay hai vi phit sinh dich b^nh, nhit la djch benh do nhdm vi khuan, vi riil Vibrio gay ra [8]. Benh lan truyen nhanh va rdng, khd giii quyet kip tiicri. Do mdi trudng khu vuc dam bj d nhiem kcl hgp vdi suthay ddi khic nghiet ciia thai tiet, sd ngay [jing cao. do boc hoi ldn. han hin thudng xay ra, nhieu ao dia nudi tdm ca da bj bd hoang vi khdng du nudc trong qua trinh nudi.
Cho den nay, van chua cd mgt tii lieu chuyen khio hoac mgt cdng trinh nghicn eiiu cu the nao v^ anh hudng. lac dgng true ticp cita BDKH den vice suy giim RNM vi DDSH - RNM. Cic nhi khoa hgc vi chuyen gia mdi irudng deu cd chung nhin djnh, xu hudng thay ddi ciia Ihdi licl khi hau, thiiy van, die biel li ihay ddi nhict do, lugng mua im, dp man, do due phii sa. tap chit lo lung trong nude dim Ihdi ky mua lut hoac sir ihay ddi mdi trudng do d nhicm va BDKH chic chin se mang lai hau qui tieu circ, lim nhieu loan rat ldn den dicu kicn sinh thai RNM. den boat ddng kiem an, luu Iru cung nhu mgt sd tap tinh sinh hgc ciia cac loai thuc ddng vit, die biet li cic loai chim trong khu vuc dim [3,7].
Tir do. inh hudng, tic ddng rat ldn den su phai iricn RNM vi DDSH - RNM Vict Nam, Irong dd cd RNM khu vue dam Thi Nai.
3.2. Cac xu the BDKH d Q u y Nhon va tinh dc ton thuong ciia dan cu khu vuc dam Thj Nai 3.2.1. Cac xu Ihc BDKH va kjch ban BDKH 6 Tj). Quy Nhon
* Xu the bien ddi nhiet do
Theo [9]. lir nam 1957 den nay, nliidl do trung binh nam cua Tp. Quy Nhon ed xu hudng ling din ru 1957- 1984 tang 0,1 "C/lhap ky; lii 1985 - 2004 cd \u hudng lang manh' 0,2"C/lhap ki
Nhicl do ihip nhat Irung binh nam cd xu hudng tang Icn 0.4"C lir 1965 - 1974. nhung lir 1975 - 1984 giim 0.3"c vi tir 1985 - 2004 tang 0,7 "C/hai Ihap ki, trong dd thdi ki miia ha ting tu 0,5"C ddn 0,7 C, Ihdi ki miia ddng ting 0,7'^C den 1.2"C. Nhict do eao nhit Irung binh cd xu hudng tang d tat ca ..cac thap ki; trung binh trong mgt thip ki laiigO, 15"C. Nhu vay, nhict dp ciia Quy Nhon co xu the dang
nong din Icn eiing vdi xu the ndng len tren pham \ i loan can.
^ Xu the bien ddi lugng mua
' Tir dau XX den nay, lugng mua nam d Quy Nhan cd su thay ddi lang, giim bit ihudng: Tang din tir 1906 - 1964, giim din tir 1965 - 1984; Tir 1985 - 2004 cd xu budng ting dan. Nhu vay, lugng mira nam cd su thay ddi thit thudng ciing vdi su ndng Icn ctia nhiel dd.
1 * Kjch bin BDKI 1 d Tp. Quy Nhon
Tren ea sd nghien cii'u su thay ddi cua yeu td nhict do vi lugng mua d Tp. Quy Nhon, cac nhi pioi hgc di du bao, den giira the ky XXI, nhiet do
Jrung binh hing thing vi mua ciia Tp. ddu lang. N«.i.«-ungi>i.>BuiTPQu,ifl>cmo,.ofc«hMnBi Nhiet dp trung binh t h i n g cd the t i n g d i n 1,5°C, | -.-..-.. - ^™-| j Iirgng mua t i n g v i o miia mua, g i i m vao miia khd.
IJen nam 2050, lugng mua miia khd giam khoang i^ " _ 14,5 mm v i Iugng m u a miia m u a tang k h o i n g ;| " y ' ' ^ ^ ' ^ ^ ^ ^ ^ ' N ^ ^
82,2mm, m u e N B D ed tha dgn 30cm. Dien tich '^ ' ^ ^^"^-^^
igap lyt ciia Tp. tang khoang 1,47 k m ^ Ciing theo j " ''^"'^ i Mch ban BDKH, "hi?n tugng thdi ti^t k h i c nghiet ; '^j . _ _ ^ ^ „ _ _ _ _
"gay c i n g diln bien phurc tap va cd xu h u d n g I \^' " • •• •• \
"gay mgt xau han".
j Hinh 2. Nhiet do trung binh tai Quy Nhcm theo kich ban B2 [9]
DjA LY Tl/NHIEN, TAI NGUYEN THIEN NKIEN VA MOI T R U 6 N G 547
Hoi Dia ly vi Tii nguyen Moi truong Thua Thicn Hue. Hgi Dja ly Vict ^an,
Theo dd, nhiet do trung binh cac thing deu tang, cd thi tang den l,5''C/thing. Thing IV dugc du bao li thing cd mu-c ting nhiet do cao nhat.
Thing V - VHI nhiet do trung binh thing cao han 30''C.
III'. ..11 i I II l i l l
Hinh 3. Lugng mua trung binh tgi Quy Nhcm iheo kich bdn B2 [9J Lugng mua trung binh tang vio miia mua va giim vao mua khd. Den nam 2050, lugng mua miia khd giam khoing 14,5mm/thing, miia mua tang khoang 82,2mni/lhing. Lugng mua tang manh vao cac thing IX - XO va giim manh vao cac thing 111 - V.
Hinh 4. Vung chiu tdn tlncang do bao, xdi la, xdm nhgp mdn, nggp lyl vd han hdn f9]
Ket qui dinh gia tinh trang de bi tdn thuang chung cho Tp. Quy Nhan tai cic Hgi ihao Doi thoai, hgc hdi vi chia se thich nghi, ung phd vdi BDKH d Tp. Quy Nhon da xac dinh cic vin dc chinh do BDKH giy ra li bao, trieu cudng, ngap lut, xdi Id bd bidn - bd dim, xam nhap man, han han vidi chuyen cit. Cic hiem hga nay cd kha nang giy tdn thuong ddi vdi suy giim TNTN, trong do co lai nguyen DDSH - RNM, tinh mang, tii sin, ca sd ha ling KT - XH, ddi sdng va sinh kc ciia cac cong ddng dan cu toin Tp ndi chung vi khu vuc Thi Nai ndi rieng.
3.2.2. Tinh de tdn thirffng cua cong ddng dan cir khu vuc dam Thj Nai
Ket hgp phan tich thdng tin tir ket qua khao sit, dieu tra bang bang hdi va phdng van true tiep ve tinh tdn thuong cua cgng ddng dan cu khu vuc dam Thj Nai, chii yeu li dan cu d thdn Vinh quang, xa Phudc Son, huyen Tuy Phudc - la thdn cd sd din sdng tip trung ddng diic nhit va sinh ke gin hen vdi vice khai thic va nudi trdng thiiy san ven dam, cho thay:
- Quy md trung binh cua cac hg gia dinh duac dieu tra li 5,3 ngudi/hd. Trong do, hg nghco 21,8
%, can ngheo 62,2%. Binh quan mdi hg gia dinh cd khoang 2,5 - 2,7 lao ddng; trong dd lao ddng nam 52%, lao dgng nu 48% (Bang 3). Nghe nghiep chinh eua cu dan d day li khai thic vi nudi trdng thuj^
sin, chu yeu la nudi tdm thim canh, quing canh vi nudi cua, ca (83.5%), thu nhip trung binh W 700.000 ddng - 900.000/lao dgng/thing, mgt sd it lao dgng lam rugng va trong rau cu, chan nudi heo (10,2%), thu nhap trung binh tir 600.000 dong - 800.000/lao ddng/thang, so It cdn lai (6,3%) lam nghe budn ban nhd, iam thue, thg ne, thg mdc theo miia, dinh bit gia eao, xung dien, xiet miy... tren viing
i 9/2on Hdi nghi Khoa hoc Dia ly Todn qudc ldn lhu 6; Thdnh pho Hue,
Iljjpia ly vi Tai nguyen Moi truong Thira Thicn Hue Hoi Pia ly Vict Nam
dim di sinh sdng, thu nhip khdng dn djnh, Cd den 56% cac hd gia dinh cho bidt cd them nghe phu nhu chay xe dm. budn bin lit vat, lain thue. .
- Chu hd gia dinh lu>cl dai la nam gidi (99%) Trinh do vin hda ciia chu hd chii ydu li cip I vi cap II (74,5%). Van cdn mdi sd chii hd mil chir, Hp nghco cd ty le ehu hd mii chCr cao. Cd 98% hd gia
^inh cho bicl cd con di hgc. nhung so hoc cip III rit it (2%), gin nhu khdng cd ngirdi hgc dai hoc, chi c6 2 hd gia dinh cd con daiig hgc eao ding vi irung cap Mdt sd hd cho bict vice hgc cap III cua con cai hp da phai bi dirng lai dc niiru sinh eiing vdi gia dinh.
Bang 3. Ttnh hinh nhdn khau. lao ddng. nghe nghiip cdc hd DT a thdn Vmh Quang. xd Phudc San Quy mo hg
5,3 ngucri/ho
Loai ho Ngheo
(%)
21.8 __
Can nghco
(%)
62,2 G I O I Nam {%) 51.7
tinh
(%)
NO•48.3
Lao d9ng Nam
(%)
52.0
(%)
Nir•18.0 Nong
(%)
10.2
Nghe iigliiOp Thuv san 1
(%)
83.5 1 Khac
(%)
6.3 - d Vinh quang. bd nghco cd ty le nhi lam va nha ban kien ed cao hon hd can nghco. Ty le hd ngheo sdng trong nhi tam la 24,54% vi nlia bin kicn cd li 75,46%. Trong khi dd, ty le niy doi vdi hd can ngheo la 9.7% vi 91.3%).
Bang 4 Trinh trang ' Tinh trang nha cua
T a m (%) B i n kien cd ('/u) Kicn c 6 ( % ) Chung {%)
ihd / cua cite ho diiu Ira (%) Ild nghi'u
24,54 75.46 0.00 100.00
Ho ciin ngheo 9,70 1 91.30
4,00
100,00 1 - Mat khae, tinh trang ve sinh d day rat lac hiu. Ty lc cic hg dieu tra khdng cd nhi ve sinh hoac cd nha ve sinh tain bg chidm tuyel dai da sd: Hp ngheo la 98%, hp can nghco gin 80%. Ci xdm khdng CO nai do ric. Diem ding luu y la cic hd khdng cd nha ve sinh khdng di nhd nhi ve sinh ciia hd khac, cd nghia li CO the hg "giai quyet vin de'* bang cich Ihii true liep vio mdi trudng sdng hoac vio vimg xung quanh dim.
Bdng 5. Tinh trgng nhd vi sinh cdc hg diiu tra Tinh Irang nha ve sinh
Khdng cd nha ve sinh Hd xi tuhoai N h i ve sinh Iam bg
Ho nghco 72.00 2.00 26.00
HO cin nghco 58,00 21,52
20,48 1
- Ddi vdi viec su dung dat dai, hd can ngheo d Vinh quang cd tdng dien tich dat sir dung chung cao hem hg ngheo khoang 1,75 lan vi tdng dien tfch dit su dung cho san xuat ndng nghiep va nudi trong thiiy san so vdi hg ngheo cQng cao han gan 2 lin. Ding luu y li chi cd 42%i hd ngheo cd chimg nhin sd hiru tdng dien tich dat sir dung chung, 30% sd hg la khdng cd chung nhin vi 38% edn lai cho Diet dit dai dang sir dung cd ehirng nhan nhung chua hgp phip Ddi vdi hg can ngheo, cic ly le tuong U'ng la 53%, 37% va 20%. Ddi vdi tinh hinh sir dung dit ndng nghiep, sd hd ngheo vi can ngheo cd chiing nhan sd hiru cung khi thap, ty le chung li 62%). Sd cdn lai li dat lu lin ehiem hoac chua sd hiru chinh thue ho^c dang chd chung nhan sd hiJu. Do vay, neu bj tae ddng bdi thicn tai va BDKH, kha nang ginh chiu hau qui va tdn that rit ning ne cho ddi sdng vi sin xuat ciia hau het cdng ddng d day.
E>!A LY TUNHIEN, TAI NGUYEN THIEN NHIEN VA MOI TRUCiNG 549
Hoi pja ly vaTai nguyen Mdi iruong Thua Thicn Hu£ Hoi Dia ly Vjc[ ^i^J - Vd nhin thuc BDKH, ch! cd 43,5%) hd dugc dicu tra da nghe ndi ve BDKH, chii yeu lirca,, phuang lien loa phdng thanh, radio, tivi... Cd den 56,5% chua tiing nghe ndi den BDKI I; Trong dd, c|,|]
cd 18%i eho ring bidu hicn ciia BDKH li su ndng len eija nhict do khdng khi. khi hau, thdi licl ilmj (jgj Ihit Ihudng, edn lai phin Idn chua cd nhan ihuc dimg, thim chi hg cdn cho rang dd li su xual hien sao chdi, dgng dat, niii lua.
- Tuy nhien, 100% hd dieu tra d Vinh Quang deu eho rang noi hg dang smh sdng nam irona vitng dl bi anh hudng bdi cac loai ihicn lai vi BDKH giy ra mgt cich phd bicn: Bao, lu lui, iii^y cudng, xim nhap man, khd han. sat Id bd... d mirc do nguy hiem \ i rat nguy hiem. Trong dd, cd hon 85% cho ring anh hudng cua cac loai thien tai nay d cudng dp manh.
- 100% hg didu tra cho rang ldm, cua, ci va ihiiy sin ndi chung li cac lo^i lai nguyen hi anh hudng nhieu nhit bdi BDKH, ngoai ra cd 39,7% cho rang tii nguyen RNM bj inh hudng.
- 100% hd dicu ira cho rang bao, lii lut, trieu cudng, xam nhap man, khd han, sal Id bd.anh hudng den gta dinh eiia ho. Trong dd, 75,2% eho rang Ihict hai ldn nhit vc nguon Igi ihiiy sin, dae bi?i ed 55,5 %i cho rang do mit RNM.
- Ticp can cic nguon von trong dicu kien binh Ihudng cd vai trd quan trgng trong vice phai trien sin xuit; Tiep can cic ngudn vdn trong dicu kicn bj Unci hai do ihien lai. BDKI I cang cd vai trd quan trpng han ddi vdi vice khdi phuc vi duy Iri cic hoat ddng sin xuit cung nhu dim bio cudc sdng binh Ihudng cho ngudi din. Cd 47,14%) hg nghco cho bict hg dugc tiep can cac ngudn vdn vay va dirac hfi trg khdng Ihudng xuyen cic loai luong thuc, mi tdm; 46,15%) hg can ngheo cho bict hp dugc vay von khdng thudng xuyen de san xuat, khdng pbii de phdng chdng, khic phuc hiu qui ciia ihicn lai.
Bang 6. Tinh hinh liip can cdc ngudn vchi eiia hg gia dinh diiu tra
Duoc vay von & ho t r g uong thyc C6(%)
Kh6ns(%) Chung(%)
Lo^i h9 Nghco 47.14 52,86 100.00
Can nghco 46,15 53,85 100.00
Chung 1 46.88 53.13 100,00 1
• Chi cd 10% hd cho bict gia dinh ctia hg da tham gia khdng thudng xuyen vio cac hoat dgng phdng chdng thien tai va giiin nhe tic dgng ciia BDKH tai dia phuong; 90% trong dd cho biet cic hoat ddng cu the la trdng RNM, be dit viing bd dim di chdng sat Id, xim thuc dit. Cd 45,5%) hd cho biet hg dugc tham gia true licp vao duin trdng RNM, 15% vio duan nuoi thiiy san thich nghi d dam Thi Nai.
KET LUAN
RNM vi DDSH - RNM ndi chung ciing nhu da dang cac loai RNM ndi ricng d dim Thi N?i khu vuc Tp. Quy Nhan dang dirng Irudc thuc trang bj suy giam nghiem trgng ve sd lugng vi chat lugng, inh huc.ig true tiep den TNTN - MT vi ddi sdng dan eu khu vue ven dim. Trong bdi canh BDKH dang dien ra phirc tap hien nay, kha nang chong chju vi thich nghi ciia cdng dong dan cu khu vuc niy rat thip da lim ting nguy co bj tic ddng, suy giim RNM vi DDSH - RNM ciia khu vuc cang hien huu va nang ne hon.
Do vay, can thidt phai cd djnh hudng cic giii phip nghien cuu bao ton RNM va DDSH - RNM dim Thj Nai. Djnh hudng cac giii phip bao tdn phii dua tren co sd Kc hoach hanh dgng bao ve, phai irifin RNM Viet Nam; Quy hoach phal triSn RNM, khai thac, nudi trong thiiy sin tinh Binh Djnh va Tp- Quy Nhan; Hien trang RNM va DDSH - RNM dim Thj Nai; Nhimg khd khan ve dan sinh KT - XH Wi"
550 Hdi nght Khoa hoc Dia ly Todn quoc ldn thii: 6, Thanh phd Hue. 9/2012
HfiiPja Iv va Tai nguyen Moi truQ-ng Thira Thicn Hue „ _ _ ^ ^ " 0 ' ^V^ '>' ^''?1 ^^™
ygc dim Thj Nai; Du bio xu Ihc BDKI I - kjch ban BDKH d Quy Nhan vi tinh dd ton thuang cua cdng dong dan eu khu vuc dam Thi Nai...Cic djnh hudng giai phip chii yeu li Tang cudng giao due, ning eao nh^n thirc vi thay ddi co ban nhin thiic ve gta Iri HST - RNM dim Thj Nai; Quy hoach bio ve phuc hdi RNM va DDSH - RNM; Quy hoaeh su dung hgp ly dam Thi Nai, Xay dung, to chirc vi thuc hicn quy che quan ly dim; Giii jihip ho trg edng ddng, xay dung nang luc irng phd BDKH cho chinh quydii \a cpng dong; Giii phip vc co ehe hgp lac, dau lu; Giii phip kt ihuil - cong nghe vi phit irien nguon nhan lyc qiian Iv. bio ve dim...
TAI LIEU TIIAM KHAO
1. Bo Tat nguyen v;i Mdi truinig, Ke hoach hanh ddng Bao vc va phal iricn rimg ngap man Vict Niun deii 2015.
2. Dai K"!"&TV Nam Trung bg, Dac dicm khi hiu Ihity van linh Binh Djnh. nam 2007.
3. John Pilgrim, Bird Life Intcrnalional. Dinh gia nhirng tie ddng chinh ciia bidn ddi khi hiu ddi vdi da dang sinh hpc Vict Nam. Ky yeu Hdi thao Tic dgng ciia bien ddi khi hiu vi kc hoach hinh ddng cho dia phuang: Trutrng hgp mien Trung Vict Nam, NXB KK&KT, 2008,
4. Nguyen Thi Lien. Hien irang nudi trdng thuv sin vi nhirng boat ddng trien khai nham phit trien nudi trdng Ihuy san ben viing lai dam Thi Nai mien Trung Vict Nam, Ky vcu llgi Ihao Mdi Iruimg ndng nghiep - ndng thdn va da dang sinh hpc d mien Trung Vicl Nam. lUCN Viclnam - IRF.B.
NXB Dai hgc I lui 2009.
5. Tran Fhi Thu Hi. Dicu Ira khio sit \ i nghicn cint phuc hdi he sinh thai, sir dung hgp ly vi bao tdn ngudn lai vimg Cdn Chim - Dim Thi Nai Iinh Binh Dinh. Sd Thiiy sin Binh Dinh, 2005.
6 Vii Thi Ngoe - Nguyen Ngoc Khanh, Bao tdn, phii iricn da dang sinh hgc - Van dc cin quan lam Irong chuong trinh hanh ddng thich img vdi BDKH tai Vict Nam. Tuyen lap eic cdng Irinh khoa hpc Hdi ngliFKhoa hgc Dia li - Dia chinli. Dl IQG I Ii Ndi, thing 9/2010.
7. Pham Binh Quyen \a nnk, Xi\ dung kc hoach hanh ddng da dang sinh hpc tinh Binh Dinh den nam 2010, Trung lam Nghien ciru tai ngu>cn \'i mdt trudng. DHQG Hi Ngi, 2005.
8. Trail Thi hdng Sa - Le Van Thing. Tim hicu tic ddng ciia nudi trdng thiiy sin den mdi trudng nudc d dim Thj Nai, tinh Binh Dinh. Ky yen lldi ibio Mdt trudng ddi ven bd cic tinh duyen hai mien Trung VN, NXB Dai hgc Hud, 2010.
9. UBND Binh Djnh, Xiy dung kc hoach hinh dgng irng phd vdi BDKH tinh Binh Djnh irong khudn khd, chuang Irinh muc lieu qudc gia ung phd vdi BDKM, 2012
10. Lucmg Thi Van. Nghien cuu bio ton da dang sinh hgc rirng ngap man Tp. Quy Nhon trudc tic ddng cita bicn ddi khi hau. De tii Cip Trudng 2011 (Ma sd T2011 325 35)
D!A LY TU'NHIEN. TAI NGUYEN THIEN NHIEN VA MOI TRU'CJNG
