192 Tuyen t§p HOi nghi KHOA HQC T O A N Q U Q C V £ SINH HQC BigN VA P H A T TRifeN B £ N VLTNG
LirONG GIA KINH TE GIA TRI PHI StT DyNG CUA HE SINH THAI CO BIEN TRONG PHA TAM GIANG - CAU HAI
(THlTA THIEN - HUE)
Nguyen Thj Minh Huyen, Do Cong Thung, Hoang Thj Chien, Pham Hai An, Tran Manh Ha
Viin Tdi nguyen vd Moi trudng biin, Viin Khoa hpc vd Cong nghi Viit Nam
L M d D A U
Cic nha khoa hpc da chi ra rang cac tham cd bien frong b? dim p h i Tam Giang - Ciu Hai (TG - CH) la nai cu tru, la bai gidng, bai de quan trpng cho tdm, ca va nhieu loai thuy san cd gia frj khic (Nguyen Van Tien, 2004). Do cd cac tham cd bien, cdng vdi ngudn dinh dudng hiru ca tir cac con sdng dd vao, nen nang suit sinh hpc sa cip trong dim phi Tam Giang - Cau Hai cao hon cac thuy vyc xung quanh. Ngudn dinh duang hiru ca nay giup duy tri nang suit sinh hpc sa cip ciia quan xa thyc vat phii du, rong bien, cd bien d mirc dp cao. Cic yeu td tren ket hgp lai de duy tri nang suit nghe ca va ngudn lgi sinh hpc. Tiep theo, nang suit sinh hpc cao giup duy tri mpt sd lupng ldn cac loai chim nude di cu va ban dja.
He dim phi niy cdn la viing dem ven bd nham bio ve viing ddng bang ben frong khdi bj man boa, dieu chinh vi khi hau cac khu vyc dan cu ddng due, cung nhu cac canh ddng trdng trpt vdi mirc dp thim canh cao. Dam pha cung la dudng giao thdng thuy ndi lien thanh phd vdi vung ling que ven dam pha, cung cap nhirng dia diem xiy dyng cing bien cho thuyen be tni ngy [6].
Trong khudn khd de tai cip vien Khoa hpc va Cdng nghe Viet Nam nam 2008-2009, npi dung"Lupng gia kinh te mpt sd gia tri phi sir dung cua he sinh thai (HST) cd bien frong pha Tam Giang - Ciu Hai" da duac nhdm nghien ciru thupc Vien Tai nguyen va Mdi trudng Bien tien hanh. Bai bao nay nham gidi thieu mpt sd ket qua nghien ciru budc dau dat duac.
II. PHUONG PHAP LUgfNG GL\ KINH TE CAC GIA TRI PHI SIJ' DUNG CUA HE SINH THAI CO BIEN TRONG DAM PHA TAM GIANG - CAU HAI
Viec dinh lugng mpt each chinh xic cic gia tri phi sir dung (hay cdn gpi nhdm gia frj chua sir dyng) ciia h? sinh thai cd bien frong dim pha TG-CH la het sire khd khan va phai sir dyng nhieu phuong phap khac nhau de cd the tiem can tdi cac gia trj dich thyc cua tai nguyen thien nhien. Viec ip dyng cac phuong phap dinh gia kinh te lien quan den khai nipm "sin long chi fra" (Willingness to pay), la ca sd de dinh gii kinh te cua nhi8u hang hoa va djch vu. Trong mpt nen kinh te canh franh, cd the ndi rang gii thi frudng phan anh gia sin long chi fra ciia ngudi tieu dimg cho cac hang hoa, dich vu. Ddi vdi gii fri sir dung tryc tiep thu dugc tir cac he sinh thai, gia thi tiirdng la phuang phip thoi dang de do luong. Nhung dS tinh toan cac gia frj lien quan den giao thdng, van hoa, giao dye va nghien cuu khoa hpc cua dim phi lai khdng thd ap dung cac phuong phap gia ca thi frirdng de tinh toin.
Trong nghien cim niy, phuong phip chi phi thay the va dac biet phuang phap danh gia ngiu nhien (CVM) dugc su dyng de danh gia cac gia tri chua sir dyng.
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1. Nhom doi tuong nghien cuu va dieu tra
- Thu thgp thong tin thir cap: thdng qua cac bao cao ve cac gia trj ngudn lgi dugc mang lai cho cdng dong din cu dim pha TG-CH. Tir cic bio cio tip hgp dugc, nhdm nghien cim rut ra each tilp can phii hgp de xiy dyng phuong phap luan, lip bang hdi phii hgp vdi muc tieu nghien ciru [3, 4, 6].
- Doi tuprng nghien ciru: Nghien ciru nay nham lupng gia kinh tk. cic gia fri phi sir dyng cua he sinh thii cd bien trong dam pha TG - CH, nen ddi tupng nghien cim bao gdm khu vyc dan cu dim phi. Trong pham vi hep cua npi dung nghien cim, chiing tdi khdng thk tiln hinh dong deu tren ci 5 huyen quanh dim p h i va da lya chpn huypn Phu Vang de tien hanh thu mau dieu tra vi diy la huyen cd sd xa va sd hd khai thic thuy san ldn nhat quanh dim phi va he sinh thai cd bien.
- Bdng hdi: Viec khao sat dugc thyc hien bang phuong phip dieu tra chpn miu ngiu nhien la sir dung bang hdi.
2. Phuong phap danh gia ngau nhien (Contigent Valuation Method - CVM)
Danh gia ngau nhien (ten gdc li Contingent Valuation - CV) hay Phuang phip dinh gia ngiu nhien (CVM) la phuong phap dugc sir dyng de dinh gii hing hoi chit lugng mdi truong khdng dua tren gia thi trudng, dac thii cho nhdm gia frj phi su dung... Bang each xay dyng mpt thj trudng ao, ngudi ta xic dinh dugc him cau ve hang boa mdi truong thdng qua sy san long chi fri ciia ngudi din (WTP) hoac sy san ldng chip nhin khi hp mat di hang hoa do (WTA), dat frong mpt tinh hudng gii dinh. Thi trudng thi khdng cd thyc, WTP thi khdng the biet trudc, ta gpi diy la phuong phap "ngiu nhien" la vi the. Mpt khi tinh hudng gii thuyet dua ra dii tinh khach quan, ngudi tri ldi diing vdi hanh ddng thyc ciia hp thi ket qui ciia phuong phap la kha chinh xac. Cic nha phan tich sau dd cd the tinh toin mirc san long chi fra trung binh ciia nhimg ngudi dugc hdi, nhan vdi tdng so ngudi hudng thu gii trj hay tai sin mdi truong thi thu dugc udc lupng gia tri ma tdng the dan chi tra cho tai sin dd [9, 10, 11, 12].
III. CAC GIA TRI PHI StT DUNG CUA HE SINH THAI CO BIEN TRONG PHA TAM GIANG - CAU HAI
1. Cac gia trj phi sit dung ciia dam pha Tam Giang - Cau Hai
De cd the lupng gii dugc gia tri cua cac HST quy doi sang gia trj tien te, can nam dugc ca ciu va sy van ddng cua cic thanh phan thudc HST trong khdng gian va thdi gian se tao nen cac loai hang hoa va djch vu hp sinh thai. Dac biet can nam vung chirc nang ciia cic he sinh thai ciing nhu mdi quan he giira chirc nang va djch vy he sinh thai. [8].
Nhting chiic nang mdi trudng sinh thai ciia he dim pha thyc chit ciing chinh la nhung gia frj khdng tinh toan, dinh lugng dugc. Tuy viy gia tri cua nd cd the cao hon, quan trpng ban nhieu cac gii frj tai nguyen cu the dugc xic dinh va khai thac tryc tiep. Ddi vdi he sinh thai cd bien trong pha TG-CH, cac gii frj phi sir dung se bao gdm:
1.1. Chiire ndng sinh thdi, bdo ve vd moi trudng song
Viing dit ngap nude (DNN) dam phi TG-CH la mpt kho dinh duong giau cd d mpt vung ven bd ngheo kift, viing DNN dim pha TG-CH luu giir va tao mpt chu trinh vat chit khep kin, ty lam giiu va xuit khau sinh dudng ra vimg bien ven bd [3, 4, 6, 7].
194 Tuyen t$p Hpi nghi KHOA HQC T O A N Q U O C Vfe SINH HQC BI^N VA P H A T T R | £ N B £ N V O N G
Mdi trudng man Ig thay ddi theo miia va sy cd mat cua dang mdi trudng sdng thuan Igi cho cu tril, sinh sin theo miia ciia nhieu ddi tugng tdm ca v i chim nude. Sy phong phu ciia moi trudng sdng nhu cira sdng, dam lay cd, tham cd bien, viing day biin, day cat v.v. da tao nen da dang sinh hpc cao va b i o ve sinh vat trudc nhimg bien ddi bat lgi cua ty nhien va sy khai thac qua mirc ciia con ngudi.
Theo ket qua thyc nghiem va tinh toan, nang suit so c i p thyc vat ndi dam pha trung binh 3pO-450mgC/m''/ngiy d ting mat, 150-280mgC/mVngay d ting day, thap hon gia tri trung binh d cic dim pha mien Trung. Nhung chinh nang suit so cap ciia vyc nude dugc den bii bang sinh khdi ldn, tdc dp phat triSn nhanh cua rong tio va cd nude. "Rimg cd nude" dudi day dam pha, ngoai tao mim ba, cung cip thirc an tryc tiep cho ca, cdn cd vai frd quan frpng dieu hda sinh thai vyc nude, tao ra oxy hda tan frong ting day kha cao, thudng 5mg/l mac dii hoan luu thing dirng kem va dac biet ludn tao ra ldp nude sit diy mit me ve miia he, cd nhipt dp thip hon tang m^t va khdng khi 2-3''C.
Mat khac, la thyc vat dinh dudng ty dudng, tham cd bien cd the hap thu cac chat dinh dudng thai ra tir sinh boat din sinh, tir cac boat ddng nudi trdng ven bd, gdp phin lam giam nguy CO giy d nhiem mdi trudng v.v. Bang phuong phap ngoai suy ta cd the thay vai trd ddng gdp ciia thim cd bien trong viec lam sach mdi trudng nude, gdp phin lam tang chit lupng nude trong dim va hieu qua nudi frdng cung nhu duy tri ben viing cac tiem nang sinh thai.
Tao nen lugng vat chit hiru co ldn cho he sinh thii dim pha nhd nang suit so c i p cao. So bp cd the tinh toan dugc lupng cacbon sinh ra tir tham cd bien len tdi hang tram nghin tan /nam.
Ndi each khac neu theo cac nghien cuu cua Kenyon, 1998 [5] thi lupng oxi sinh ra cho cac lo^i ddng vat thuy sinh sdng frong dam p h i len tdi hang tram nghin tan /nam. Mdi trudng nude frong sach diy du oxi boa tan se gdp phin lam tang tdc dp phit frien cac loai thuy sin sinh song trong dim, lam tang qua trinh phan buy cac loai vat chit hiru ca dugc sinh ra tir chinh cac lo?ii rong, cd.
• Thim cd bien la noi cu tru cho mot khu he ddng vat day vd ciing phong phii lam nguon cung cip thiirc an cho cic loai ca an day. Sd lieu ciia Vien Tai nguyen va Mdi trudng bien nam
1999-2000 cho thiy biomass ciia SVD d muc kha cao, bien ddng tir 8 4 - 1 0 6 g/m^.
• Hon niira thim cd bien cd vai trd vd cimg ldn khi li nai tru an cho cac loai tdm, cua nhat li giai doan cdn non khdi sy fruy dudi cua cic loai ca dir nhu ca vugc, ca frap... lam cho hieu qui nudi cao hon. La bai cu fru cho cac loai iu triing tdm ca khi cdn d giai doan iu trimg. Ket qua nghien cuu nam 1999-2000 ciia Vien Tai nguyen v i Mdi trudng bien cho thay sd lugng ngudn gidng tdm, cua, ca fren cic khu tham cd phong phu hon cac khu vyc khac khdng cd co gap 2-3 lin. Ngudn gidng nay tao co sd quan frpng khdng nhung cho gia trj sin lugng thuy san tai dim pha ma cdn cho sy phat frien cua ngudn Igi thuy sin d cac vimg bien lin can. Chinh vi viy cic bai cd bien dam bio cho ngudn tai nguyen thuy sin d viing ven bd dugc duy tri d trang thai can bang, cd the khai thac lau dai. Ngudn thu nhap tir vipc khai thac tdm, ca, ddi mdi v.v.
phy thudc vao mpt phin sy tdn tai va phit trien cac bai cd bien. Day chinh la nhirng gii tri sir dung va phi sir dyng de lai phuc vu cho the he mai sau nhu mpt thu cua de danh va khai thac lau dai. Viec cac bai cd bien dugc bio ve tdt, trd nen nhiing noi cu fru ly tudng, nhiing bai gidng, bai de cua cac loai thuy sin va la ngudn thiic an cho cic loai ddng vat bien, cdn cho nhirng lgi ich khac. Dd la noi duy tri sy giau cd ve da dang sinh hpc bien, trong dd da dang ve ngudn gen di truyen va da dang gidng loai.
Nhu vay, cd the thiy gia trj phi sir dyng Idn nhit ciia tham cd bien TG - CH la gia frj bao tdn tii nguyen v i mdi trudng [3, 4, 6, 7].
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1.2. Cdn bdng tu nhiin vd sinh thdi ven bd
Xet ve tdng the, sy tdn tai ciia HST cd bien cd anh hudng va tie dpng nhat djnh den phin bd va bdi lang trim tich ven bd, luu giii- va xuat khiu dinh dudng, ngudn gidng ra bien, tao noi cu tril, sinh de cho cac thiiy sinh bien di cu miia tren quy md rpng Idn.
1.3. Phdt trien kinh te-xd hpi
Thim cd bien la mpt HST trong viing dit ngap nude, ngudn Igi va cac gii tri dugc mang lai tir he sinh thai nay da gdp phin khdng nhd trong viec phit trien kinh te va ddi sdng din sinh hing ngay ciia mpt bd phan dan cu dim phi, ciing nhu ddng gdp cac gia trj to ldn cho toin vting DNN dim phi TG-CH va vimg bien ven bd thudc tinh Thira Thien - Hue.
Khdng cd noi nio d nude ta, mpt vimg DNN dim phi TG-CH lai hdi tu xung quanh nhirng khu vyc dan cu ddng diic den vay. Vai trd to ldn ciia nd da hinh thanh nen khii niem "cu din dam phi", cung tuong ty nhu "cu dan ddng bang", "cu dan mien niii" viy. Cu din dim phi cd nhieu net rieng, ddc dio ve tip quan sinh boat, phuong thirc va ngu cy dinh bat thiiy sin, le hdi... Dd la nhiing gia tri ben frong ciia he sinh thai cd bien vi cac hgp phin ciia chiing, khdng ke cac kha nang sir dung hien tai hay tuong lai, nhu van hoi, thim my, di sin. Gii frj niy cd dugc cdn tir y thirc luu tdn tai nguyen dya tren dire tin vi cic gia fri phi vat the lien quan den ddi sdng van hda, tim linh v.v.
2. Cac ket qua luong gia kinh te cac gia trj phi sur dung tinh toan dup^c trudc day
Tuy ddng vai trd quan frpng nhu viy, nhun^ cho den nay de cd the lugn^ gii kinh te dugc cac gia frj phi sir dyng ciia HST cd bien trong dam pha cdn la mpt bai toin rit khd ddi vdi cac nha quan Iy va khoa hpc, ngoii tic gii Trin Van Tuan (2002) sir dung phuong phip dinh gii ngau nhien de lugng gia gia tri bao tdn ciia toan he dim phi TG - CH, chua cd nghien ciru nao ve cac gii trj sir dung va cac lgi ich ve sinh thii va mdi trudng ciia cic thim cd bien d he dim phi niy. Tie gii Trin Van Tuin khi sir dung "phuong phap danh gii ngiu nhien" de xic djnh gii fri bao tdn ciia dim phi TG - CH, thi gii fri trung binh hang nam li 55.221 VND (3,5 USD)/
Ihd gia dinh, tir dd suy ra thu nhap ciia tinh khoing tren 11 ti VND/nam (700,000 USD/nam).
Qua 5 nam vdi ty le lai suat 10%, thi gia frj bio tdn ciia TG - CH se la 49.244.924.963 VND (3,3 million USD) [3, 4, 7].
De lip diy khoing trdng khdng ding cd dd trong nghien ciru cic gia trj kinh te thu dugc tir cic gia fri phi sir dyng ciia cic he sinh thai, sir dung phuong phip gii thay the do Alan White (1998) de xuat tinh Igi ich ve mat sinh thii ciia cic thim cd bien nhu li bai gidng, bai de ciia cic loai thuy sin cd gii tri kinh te bang 20% tdng gii trj thu dugc tir nghe khai thac thuy sin d khu vyc dd [7]. Dya fren y kien tren, nhdm tic gii Nguyen Van Tien (2004) da tinh dugc gii tri sir dung gian tiep ciia cic tham cd bien frong dim phi TG-CH vdi tu cich li cic bai gidng, bai de la hon 5 ty ddng hay 325.633 USD va la he thdng xir Iy nude, duy tri chat lugng nude ciia dim pha
vdi gia tri la 6,309 ty ddng hay hon 407.000 USD My [7]. , . IV. KET QUA LUpTVG GIA KINH TE CAC GIA TRI PHI StT DyNG CUA HE SINH
THAI CO BIEN TRONG PHA TAM GIANG - CAU HAI
Phucmg phip danh gia ngiu nhien (CVM) dugc sir dung trong nghien ciru tai huyen Phii Vang nham dinh gii mirc san long ddng gdp ciia ngudi din vao quy bio tdn, nham khdi phyc tinh da dang sinh hpc, mdi trucmg ciia HST cd bien trong phi TG-CH. Tir WTPtb/'hd ciia miu, ta se tinh dugc tdng WTP ciia toin bd khu vuc nghien ciru. Tdng gia trj ma ngudi dan san ldng chi
196 Tuyen tap Hpi nghj KHOA HQC T O A N Q U Q C V 6 SINH HQC BI^N vA P H A T T R I ^ N B £ N VCTNG
fri de phyc hdi da dang sinh hpc, mdi trudng chinh la tdng gii tri chua sir dyng toin khu \arc nghien cim. Ket qui nghien ciiu va tinh toan da cho thiy.
1. Dac diem ciia viing nghien ciiru
7.7. Dieu kien kinh te xd hpi viing nghien ciru (huyen Phu Vang)
' Phii Vang la huypn ven bien va dam pha cua tinh Thira Thien - Hue. Nam ve phia Ddng thinh phd Hue, dia hinh cua huyen kha phiic tap, dit rpng, ngudi ddng. Toan huyen cd 20 xa, thi frin. Tdng dipn tich dit ty nhien: 28.038ha (dat ndng nghipp: 10.829ha, dat phi ndng nghipp:
13.932ha; dit chua sir dyng: 3.269ha).
Dan sd 176.019 nhin khau, 83.128 lao ddng. Trong dd cd 13 xa, thi fran ven bien, dam phi vdi dien tich 20.635ha, chiem 73,6% dien tich dit ty nhien ciia huyen, cd 23.975 hd, 126.485 nhan khiu, 58.551 lao ddng, chiem 7 1 % din sd toan huyen, sdng chu yeu bang nghe danh bat va nudi frdng thuy sin. Huyen cd tren 35km chieu dii bd bien, cd cira bien Thuan An va nhieu dim nhu Dam Sam, D i m Chuon, Dim Thanh Lam, Dim Ha Trung, D i m Thuy Tii nam trong he thong phi TG - CH vdi dien tich fren 6.800 ha dit mat nude, la tiem nang ldn de phit frien dinh bat va nudi frdng thuy sin. Diy la nganh kinh te miii nhpn, la the manh, lgi the so sinh de phat trien kinh te - xa hdi tren dia ban [1].
1.2. Hien trgng nuoi trong thuy sdn cua huyen vd tgi cdc xd cd dam nuoi trong phd Tam Giang - Cdu Hai
Tinh hinh nudi frdng thuy sin (NTTS) huyen Phii Vang frong nhting nam qua phit trien manh gdm 20 xa, thj frin cd dien tich NTTS. Trong dd, cd 13 xa, thj tran phit trien dien tich nudi nude Ig, nam 2001 cd 1353ha trong dd (nudi chan sao: 51 Iha, nudi ha trieu: 662ha, nudi cao trieu: 779ha), binh quan tang hang nam 145ha, dien tich tang chu yeu dit chuyen ddi ven phi nhiem man trdng lua 1 vy nang suit thap sang nudi frdng thuy sin. San lugng nam 2001 dat 603 tin. Nam 2008 tdng dien tich thyc hien nudi frdng thuy san la: 1.979,6ha.
Bang 1. San iu>(7ng mpt s6 ddi iu'p'ng thuy san huyfn Phii Vang nam 2008 [1]
STT 1 2 3 4
061 tirp^ng thuy san Tom sii
Tom chan trSng Ca nude la Cua, ghe
Tong san Iu'p'ng thu ho^ch
Dan vj tinh Tan Tan Tan Tan Tan
San Iu'p'ng 1725,2
310 468,6
49,1 2552,9
Huyen Phii Vang la huypn cd sin lugng thiiy san khai thac tir dam pha chiem den gin 50%
tdng sin lupng ciia toan he dam pha TG - CH. Theo sd lieu thdng ke ciia Dd Nam (nam 2005) thi sin lupng khai thac thuy sin ciia huypn Phii Vang chiem 41% tong sin lugng khai thac thuy sin ciia toin dam phi TG - CH.
1.3. Ddc diem mdu dieu tra
Da tien hinh phdng vin vdi 100 ngudi din (dai dien 100 hp) cua cic xa khai thac quanh dim phi thudc huyen Phii Vang thi nam gidi chiem 60%, cdn lai la nir gidi. Trong do, dp tudi
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ciia nhimg ngudi nay nim trong pham vi tuong ddi hep: tir 34 den 55, chii yeu tit 41 den 48 tudi (chiim 60%). Sd nhin khiu ciia nhirng hp dugc phdng vin dugc dua ra d bang 2.
Bang 2. Phan bd nhan khau cua cac ho dipo-c phong v i n
Sd nhan kh^u 4 5 6 7 8 9
So hp 10 27 18 18 13 14
Ty 1? % thu nhgp 10 30 20 20 10 10
Thu nhap cua cic hd dugc dieu fra chii yeu tir 3.000.000 den 5.000.000 ddng/nam, sd it thu nhap dugc 50.000.000 dong (chiem 20%) vi 20.000.000 ddng (chiem 10%), song day cung la mirc thu nhap tuong ddi cao d khu vyc niy.
Trong nghien ciru "Sinh ke cua ngu dan ven dim phi Tam Giang - Ciu Hai", Lam Thi Thu SOai (2005) [5] da cho thiy ngu din thuy dien va dinh cu d xa Vinh Ha, mgt xa cd tai nguyen dim phi da dang vi phong phii dang sdng trong hoan canh bip benh ve nhieu mat. Khi hau khac nghiet, dat dai nhiem man, xa vdi ngudn nude sinh boat. Din sd tang nhanh, ngudn lgi thuy sin giam, djch bpnh tdm keo dai. Cudc sdng ciia hp cang bap benh khi hp thu dpng sdng trong mdi truong lien tuc cd sy thay ddi. Cac thay ddi tat yeu ciia xa hdi nhu nen kinh te thj trudng cung vdi cic CO che kem theo cua nd la chii truong phit trien nudi frdng thuy san vira md ra co hgi cho ngu din, nhung ddng thdi cd nguy co tic ddng tieu cyc den sinh ke cua ngudi din khi nd nam ngoai sy kiem soat cua hp.
Ddi sdng tai chinh ciia ngudi din dja phuong phu thupc chii yeu vao dim pha va hd tdm.
Hang ngay, mdi gia dinh kiem dugc tir 20.000d den 30.000d tir vipc danh bat, nhung thu nhap nay ciing bip benh theo miia. Nhung thing miia mua, hp kiem dugc rat it, tham chi khdng cd ddng nao. Nhiing hd nudi tdm thudng xuyen bj thua Id. Mpt vai vy diu, mot sd ngudi nudi cd hieu qua va thu dugc tir 6-7 trieu/vy, chua frir cac khoin chi phi va cdng lao dpng. Ngoai ra, cac gia dinh d diy cdn cd them khoin thu nhap quan frpng khac la tien con em hp di lam an xa mang ve hoac giri ve hang nam vao djp tet Nguyen Dan (tir 1.000.000 ddng den 10.000.000 ddng/nam) [4].
Cung chinh vi vay khi dugc hdi miic san ldng chi fra mpt sd tien cho quy phit trien va bio ton cac gia frj nhu mdi frudng, da dang sinh hpc tir he sinh thii cd bien dem lai cho cdng ddng dan cu quanh phi, phin ldn ngudi din deu ddng y nhung d mirc thip.
2. Ket qua tinh toan gia tri phi sir dung
2.1. Gid tri WTPtb
Bang each hdi miic san ldng ddng gdp cua ngudi dan da cho phep phuang phap chpn tinh tdng WTP, thdng qua dd tinh dugc gii trj ciia HST cd bien trong hp dim phi TG-CH, day la HST cung cap chii yeu cac djch vu nhu bio ve dudng bd, chdng xdi Id cho ngudi din dja phuong frong sudt thdi gian vira qua.
Cac bien cd inh hudng den mirc ddng gdp cua ngudi dugc phdng van (WTP) frong trudng hgp nay li: gidi tinh (GT, GEN), tudi (T, AGE), nghe nghipp (NN, PRO), sd nhin khiu (NK, POP), thu nhap (TN, INC), chi tieu (CT, EXK). Do vay phuang tiinh tinh WTP se nhu sau:
198 Tuyen tap HQi nghi KHOA HQC T O A N Q U Q C V 6 SINH HQC B | £ N V A P H A T T R | £ N B £ N VCTNG
WTP tb = p, + PiGTi + PsTi + P4NNi + PsNK, + p^TN, + P7CT,
Dependent Variable: WTP Method: Least Squares Sample: 100
Included observations: 100
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Variable Coefficient Std. Error t-Statistic Prob.
AGE EXK GEN INC POP PRO C
R-squared
Adjusted R-squared S. E. of regression Sum squared resid Log likelihood Durbin-Watson stat
1537.712 -0.000829 -6201.242 7.61E-05 -3141.885 16464.21 -28433.03 0.749999 0.684782 5333.964 6.54E+08 -296.0381 2.494360
247.4314 0.000389 2817.309 6.04E-05 812.2509 3434.896 9809.961
6.214700 -2.130545 -2.201123 1.258659 -3.868121 4.793219 -2.898384 Mean dependent var S.D. dependent var Akaike info criterion Schwarz criterion F-statistic
Prob(F-statistic)
0.0000 0.0440 0.0380 0.2208 0.0008 • 0.0001 0.0081 29500.00 9500.454 20.20254 20.52949 11.49996 0.000006
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Coeffcient Covariance Matrix •'''-
AGE EXK GEN INC POP PRO C
AGE 61222.30 -0.025969 -410124.0 0.004707 -93910.88 -56811.63 -1812091.
EXK -0.025969
1.51E-07 0.479978 -5.31E-10 0.074144 0.058977 -0.204525
G E N -410124.0
0.479978 7937230.
-0.015008 436525.4 2067627.
7313138.
INC 0.004707 -5.31E-10 -0.015008 3.65E-09 0.003365 -0.028654 -0.247520
POP -93910.88
0.074144 436525.4 0.003365 659751.5 303917.3 -782956.9
PRO -56811.63
0.058977 2067627.
-0.028654 303917.3 11798509 -11014129
C -1812091.
-0.204525 7313138.
-0.247520 -782956.9 -11014129 96235327
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C(l)
WTP tb = C(1)*AGE + C(2)*EXK + C(3)*GEN + C(4)*INC + C(5)*P0P + C(6)*PR0;+
Thay cic sd lieu tinh toan vao ta dugc: :,, WTP tb = 1537.711864*AGE - 0.0008289904416*EXK - 6201.242446*GEN +
7.606737281e-005*rNC - 3141.885009*POP + 16464.20709*PRO - 28433.03013 = 29.5000
Qua 2 bing hdi quy deu thu dugc WTP trung binh/lho la 29.500 (dong).
Tieu ban: TAI NGUYEN SINH VAT BI^N vA N G U O N LOI 199
2.2. Phdn tich cdc nhdn to dnh hudng den WTP: (chpn mirc y nghTa a = 0.05) (chung cho ca 2 each) - P-value cua F-statistic = 0.000 < mirc y nghTa nen ham tren hoin toan phu hgp
- R^ = 0.75 tire la cic bien dpc lip giii thich dugc 75% sy bien ddng ciia bien phu thupc (WTP)
- He sd chin bang -28433.03 chimg td neu cic bien khic bing 0 thi WTP vin giu d mirc - 28433.03. Dieu nay cho thiy han vin cdn nhirng nhan td khac inh hudng den WTP theo chieu nghjch lam WTP thip hon mirc binh thudng
- Gii frj P-yalue cua tudi (AGE), chi tieu (EXK), gidi ti'nh (GEN), nhin khiu (POP), nghe nghiep (PRO) deu nhd hon mirc y nghTa. Dieu niy cd nghTa tit ca cac biln nay d8u inh hudng den mirc san ldng chi fri ciia ngudi din. Trong dd P-value ciia tudi bing 0.000 chirng td mirc dp anh hudng cing ldn.
- Gia fri P-value ciia thu nhap (FNC) bang 0.2208 ldn- hon mirc y nghTa chirng td thu nhap ciia ngudi din anh hudng khdng cd y nghTa den WTP
- He sd ciia bien tudi (AGE), thu nhap (INC), nghi nghiep (PRO) <3lu duong (ciing dau vdi WTP) nen cd anh hudng thuan den WTP. Vi dy: khi thu nhap tang thi miic sin ldng chi fri cua ngudi din cung tang va ngugc lai.
- He sd ciia bien chi tieu (EXK), gidi tinh (GEN), nhin khau (POP) deu im nen inh hudng nghjch den WTP. Vi du: khi chi tieu ciia 1 hp gia dinh tang thi mirc san ldng chi fri cua ngudi dan se giam va ngugc lai. Dieu nay cung hoin toan phu hgp vdi thyc te.
Cic ket qui tinh toin dugc d tren cho thay gia trj cua WTP hoin toan phu hgp va dugc chip nhin.
2.3. Kit qud tinh todn gid tri tong WTP
Gii trj kinh te ciia cac gii trj phi sir dung tir he sinh thai cd bien trong dam phi TG-CH frong trucmg hgp nay se tinh nhu sau:
WTP = W T P tb * So ho khai thac va nuoi trong thuy san trong viing
Trong bio cao "Kinh te - xa hdi viing dim phi Hue" - phin 1 ciia dy in IMOLA [2] da thdng ke dugc khoing chimg 300.000 din thudc 32 xa d 5 huyen viing dam phi (bang 3) sinh sdng bang each tryc tiep hoac gian tiep khai thac tai nguyen trong dim phi. Tir cic ket qui nghien ciiu cho thay ngudi din nudi trdng thuy sin nhu la mpt boat ddng chinh ciing lam ndng nghiep, chan nudi vi danh bat thuy sin, trong liic ndng din lam rupng nhu li boat dpng chinh cung tien hinh chan nudi, nhung nudi trdng va dinh bat thuy sin rit ban che. Ngu din cung tham gia nudi tdm vachan nudi nhung khdng lam ndng nghiep.
Bang 3. Mpt s6 dac diem v§ hanh chinh va dan s6 cua d i m pha Thira Thien - Hu§ [2]
Huy^n
Phong Dien Quang Oien Huang Tra Phu Vang Phu Lpc
Tdng cpng
So xa d^m pha / t6ng s6 xa va thj trSn thupc huy?n
(ty 1? %)
Di^n tich cac xa dam pha / dl?n tich toan huy^n, ha (%)
2/16(13%) ; 2.660/95.400 ha (3%) 8/11(73%) 1 12.184/16.307 ha (75%) 2/16(13%) [ 2.596/52.089 ha (5%) 13/20(65%) I 20.636/28.031 ha (74%) 7/18(39%) 1 29.062/72.809 ha (40%) 32/81(40%) 1 67.138/264.636 ha (25%)
Dan sd ddm pha / t6ng dan s6 (%)
10.038/105.685(9%) 63.046/92.228 (68%) 19.029/116.066(16%) 127.970/181.149(71%) 61.468/149.875(41%) 281.551/645.003(44%) Nguon: so lieu thong ke tir cdc huyen
200 Tuyen tgp HQi nghj KHOA HOC T O A N Q U Q C V £ SINH HQC BifeN VA P H A T T R | £ N B £ N VLTNg
Bang tren cho thiy dan sd sdng quanh dam phi va la ngudi khai thac cac ngudn lgi tir dim phi la 281.551 ngudi, nhung lai khdng cd con sd thdng ke vi sd cic hg khai thac va nudi frong thuy sin frong dim phi. Theo sd lipu chiing tdi dieu fra dugc tai huyen Phu Vang la cd 23.970 hp vdi 126.485 nhin khiu nam 2008 lim nghe khai thac va nudi frdng thuy san [1]. Nhu vay cd the udc tinh trung binh mdi hd sdng tai dim pha cd khoang 5,3 ngudi.
Tir dd suy ra, tdng sd hd lam nghe khai thac va nudi frdng thuy san fren toan dam pha vao
khoing: 281.551 nhin khiu/5,3 nhan khau = xip xi khoang 53.122 hg gia dinh. ^ Gii frj tdng WTP dugc tinh theo cdng thiic:
WTP = WTP tb * So ho khai thac va nuoi trong thuy san trong viing
<=> Nhu vay: Tdng sd hp khai thac thuy sin bien tren dam pha vao khoang: 53.122 hp Gia frj trung binh mang lai cho dam phi TG-CH ve vipc bao ve cac chirc nang de danh, luu tdn va chua sir dyng v.v. cua cac HST cd bien udc tinh khoang:
29.500d6ng x 53.122 ho = 1.567.099.000 dong
Tuong duong vdi 89.040 USD (ty gia nha nude d mirc: 17.600d/l USD)
Khi so sinh gia frj kinh te tir cac gia trj phi sii dyng chiing tdi udc tinh dugc, dya fren miic san long chi fra de phyc hdi quy da dang sinh hgc, bio ve ngudn lgi thuy san, mdi frudng ciia ngudi din dim phi nam 2008 vdi cic ket qua tinh toan cua tie gia Tran Van Tuan (2002) thi gii frj chiing tdi udc tinh dugc thap hon rit nhieu. Ket qua tinh toan dugc ve gia frj WTPtb ciia chiing tdi tinh dugc nam 2008 thip hon so vdi ket qua tinh toan dugc cua nhdm tie gia Tran Van Tuan nam 2002 (29.5000VND/ 55.221 VND). Dieu nay phy tiiudc phuong phap va ky thuat sir dung frong tinh toin cung nhu thdi diem dieu fra phieu nhin din. So tien ddng gdp cho xay dyng quy tai huypn Phii Vang nam 2008 rat thip vi phu thugc vao nhin thiic, trinh do hgc van va mirc sdng ciia ngudi dan dja phuong d diy cdn thip va ngheo (khi cd xa, trinh dp hgc van cao nhat mdi den ldp 6/12). Cupc sdng cua ngudi din cang khd khan, nhan thiic khdng het cac gia frj ciia HST thi mirc san long chi fra cua ngudi dan cho quy bao tdn da dang sinh hgc va mdi tnrdng dim pha cang thip.
V. KET LUAN
Ngudi din sinh sdng quanh pha da nhan thiic dugc viec bao ve cac HST trong pha TG - CH de bio ve cac gii frj de danh, luu tdn va phi sii dyng chinh la bao vp da dang sinh hgc, mdi trudng dim pha, nang suit nudi frdng va khai thac thuy sin cua ba con. Ngudi dan dia phuong da ddng y ddng gdp xiy dyng quy de phyc hdi cic chirc nang fren khi chiing bj anh hudng ho$c mit di.
Sd tien ddng gdp cho xiy dyng quy bio tdn da dang sinh hgc va mdi frudng rat thap vi phy thupc vao nhan thirc, trinh dp hpc van va miic sdng ciia ngudi dan dja phuang cdn chua cao. Ket qui tinh toin ban diu, chiing tdi da tam lugng gii kinh te cua cac gia frj chua sir dung do HST cd bien frong phi cung cap khdng cao, udc tinh khoang 1.567.099.000 ddng (tuong duong vdi 89.040 USD). Gia frj niy cd the cao hon neu ngudi dan dja phuong nhan thirc dugc la quan frgng va can thiet bao ve ciing nhu mirc sdng ciia hp cao hon, hp sin sang ddng gdp nhidu hon.
IV. TAI LIEU THAM KHAO
1. Bio cao "Tinh hinh nudi frdng va khai thic thuy sin huypn Phu Vang, tinh Thira Thien - Hue". Bio cio ciia Phdng Ndng nghiep vi Phit trien Ndng thdn huypn Phii Vang cung cap cho dl tii cip Vipn KH&CNVN (2008 - 2009).
Tilu ban: TAI NGUYEN SINH VAT BifeN VA N G U Q N LQI 201_
2. IMOLA Project GCP/VIE/029/ITA, 2006. Bao cio kinh te - xa hpi viing dam phi Hul - Phin I. Mang ludi cac trung tim nudi trdng thuy sin chau A - Thii Binh Duong (NACA).
3. Dd Nam, 2004. Gia tri su dung cic bai cd bien Viet Nam. Tap chi Nghien cim va Phat triln, Sd Khoa hgc v i Cdng nghe: frang 74 - 82.
4. Dd Nam, 2005. Lupng gia gii frj kinh te cua cic bai cd bien d hp dim phi Tam Giang - Cau Hai. Ky ylu Hdi thio Qudc gia ve dim pha Thira Thien - Hue. Thing 12-2005. bang 464-477.
5. Lim Thj Thu Siru, 2005. Sinh ke ciia ngu din ven dim phi Tam Giang - Ciu Hai. Ky ylu Hdi thio Quoc gia ve dam phi Thira Thien - Hue. Thing 12-2005
6. Trin Diic Thanh va nnk, 1998. Dinh gia tiem nang v i de xuit khu bio vp dit ngap nude hp dim phi Tam Giang - Ciu Hai. Luu trir tai Vien TN&MT Bien.
7. Nguyen Van Tien, 2004. Tien tdi quan ly he sinh thii cd bien Viet Nam. Nxb Khoa hpc Ky thuat, 2004. 131 trang.
8. Nguyin Hoing Tri, 2006. Lugng gii kinh te he sinh thai rirng ngap man - Nguyen ly va ling dyng. Nxb Dai hpc Kinh te qudc din. Ha Ngi, 2006. 139 trang.
9. Bishop, R, C. and Heberlein, T. A, 1987. "The contingent valuation method". In Kerr, G. H.
and Sharp, B. M. H. (eds) Valuing the environment: Economic theory and applications.
Studies in Resource Management No.2 Cenfre for Resource Management, University of Canterbury and Lincoln College.
10. Jakobsson, K. M. and Dragun, A. K., 1996. 'Contingent valuation and endangered species:
methodological issues and applications', Edward Elgar, USA
11. Haab, T. C. and McCoimell, K. E., 2002. 'Valuing environmental and natural resource-the econometrics of non-market valuation', Edward Elgar, USA.
12. Mitchell, R. C. and Carson, R. T., 1989. Using survey to value public goods. The contingent valuation method. Washington DC: Resource for the Futiire
ESTIMATING E C O N O M Y F O R N O N - U S E D V A L U E O F S E A G R A S S E C O S Y S T E M IN T A M G I A N G - C A U HAI L A G O O N
( T H U A T H I E N - H U E P R O V I N C E )
Nguyen Thi Minh Huyen, Do Cong Thung, Hoang Tlti Chien et al.
SUMMARY
The sea-grass beds in the Tam Giang - Cau Hai (TG - CH) lagoon are very important and serve as the habitats, nursenng and breeding grounds for the valuabe fishery species, such as shrimps, fishes and many others.
It is very difficult to quantify accurately the non-used value of seagrass ecosystem in the TG-CH lagoon. Many different methods must be applied for aproaching probably to the tine value of natural resources. The application of economic evaluated methods based on related to the concept of "willingness to pay" is the basis for economic valuation of many goods and services. In this study, the replacement cost method and the Contingent Valuation Method (CVM) in particularly were applied to estimate the non-used value of sea-grass ecosystem.
The calculated results showed that the non-used value in economy ft"om the seagrass ecosystem in the TG-CH lagoon was estimated as about 1,567,099,000 VND (equal 89,040USD).