Tgp chi Khoa hgc Tru&ng Dgi hgc Cdn Tho Phdn A: Khoa hoe Tunhiin. Cdng nghi vd Mdi Iruang: 25 (2013). 119-126
Tap chl Khoa hpc - Dai h(?c Can Thd
website: sj. ctu. edu. vn
THEO DOI HDEN TR^NG SINH THAI VEN BCJ VA NUOI THUY SAN BIEN ITNG DUNG K t THU^T VIEN THAM TAI BAC DAO PHU QUOC, TiNH KIEN GIANG
Nguyin Thi Hong Diep', Vo Quang Minh', Phan Kidu Didm' va Huynh Thi Thu Huong' ' Bg mdn Tdi nguyen Ddi dai, Khoa Moi trudng vd Tdi nguyen Thien nhien, Trudng Dgi hgc Cdn Tha
Thong tin chung:
Ngdy nhdn: 13/12/2012 Ngdy chdp nhdn: 25/03/2013 Title:
Coastal Ecology Changes and Aquaculture Management in Phu Quoc, province Kien Giang
Tirkhda:
Anh vien Ihdm, thay doi hien trgn^ ven bd; cd bien; cd long be; dc huong ludi ddng Keywords:
Remote sensing, coastal land use change, seagrass. cage culture and net pen culture
ABSTRACT
This study was implemented lo deled coastal land use changes in both landward and seaward and from that it can be supported to manage and evaluate these changes. In this study, there were 4 types of imagery including LANDSAT TM and ALOS imageries to use for monitoring the change status of coastal resources from 2006 to 2011; and high-resolution including THEOS and KOMPSAT-2 images to determine fish cage and snail net pen culture siles in ihe Northern partof Phu Quoc Island in 20II.
The coastal land use change from agricultural land and Melaleuca forest into build up area is 349.89 hectares (51 13% of the total area changing).
Benlhic habitat with seagrass increased from 10,985.84 hectares in 2008 lo 12.869.83 hectares by the end of 2010; and spatial distribution offish cage and snail net pen cultures. Finally, the spatial distribution map of coastal ecology including land use (landward and seaward) and aquaculture was developed in Northern part of Phu Quoc Island.
T O M TAT
De tdi thyc hi^n theo doi su thay doi hien trgng ven bd va nudi thuy sdn bien lu do hd trg viec qudn ly vd ddnh gid muc do dnh hudng cua cdc thay ddi ndy. Anh vien thdm LANDSA T TMdugc su dying theo doi hien trgng ven bdpltdn ddt liin tir ndm 2006 din 2011; dnh ALOS duac su dyng theo doi hiin trang co biin dudi nude tie nam 2007 din ndm 2010; dnh THEOS vd KOMPSAT-2 dg phdn gidi cao su dyng xdc dinh v/ tri nudi cd Idng be tgi dp Rgch Vem vd nuoi 6c huang ludi ddng tgi dp Cdy Sao ndm 2011 khu vyc phia Bdc ddo Phu Quoc. Kit qud thyc hien di tdi cho thdy co su thay doi hiin trgng sir dvng ddt ven bien lir ddt nong nghiep vd rimg tram thdnh ddt xdy dyng Id 349.89 ha (51,13% tdng dien tich thay ddi); diin tich cd biin tdng 1.883,99ha tir ndm 2007 din ndm 2010; vd hien trangphdn bo Ididng gian cua 2 lodi nudi thuy sdn gdm cd long be vd 6c huang ludi ddng. Ddng thai xdy dyng ban do phdn bd khong gian hien Irgng^ viing sinh thdi ven ba (phdn ddt liin vd dudi nude) vd hien trgng nuoi trong thiiy san biin khu vuc Bdc ddo Phu qudc.
I GIOI THIEU
Viing ven bien la khu vuc cd giao didn kha hep giij-a bien vd ddt lidn. Dd la noi cac qua
trinh sinh thai phu thudc vao su tac ddng lln nhau giiia bidn vd ddt lidn, cdc tac ddng nay dien ra khd phuc t^p vd nhay cdm tuang tdc
TopehiKhoohoe Tneang Dgi hgc Cdn Tha Phdn A: Khoa hge Ty nhien. Congnghi vd Mdi Irudng: 25(2013): 119-126 giu-a cac qua ttinb trdn mat ddt va bidn/thuy
trieu eao. Vung ven bd Id trong tdm ciia nhidu nganh kmh td qudc gia. Id noi ma phdn ldn cac boat ddng vd kinh td, xd hgi didn ra vd cimg la nai tac ddng den cac hoat ddng nay nhieu nhdt.
Day Id viing d^ng bdng mdu ma, tai nguyen bien phong phu, cd tfnh da dang sinh hge eao, la khdng gian sdng ciia cdc tdi nguyen sinh vdt va phi sinh vdt ddng thdi cd chiic ndng didu hda ddi vdi mdi tmdng tu nhien ciing nhu mdi ttudng nhdn tao (Clark, 1992). Su thay ddi hien ttang viing bd bien cd thd tac ddng tfch cue hoac tidu cue ddn mdi ttudng ven bidn (Li et a/., 1998; Wang era/., 2006).
Phu Quoc la hdn ddo Idn nhdt Viet Nam, ndm ttong Vinh Thai Lan, thudc tinh Kidn Giang co ngudn tai nguydn thidn nhidn vd nhdn van phong phii, da dang. Hien nay, Chfnh phu dang thuc hien ke hoach la xay dung ddo Phii Quoc trd thanh mdt thanh phd bidn dao, khu kinh td - hanh chfnh, khu trung tdm du lich sinh thai, nghi dudng vdi dich vu cao cdp, ddng thdi ttd thanh ttung tdm khoa hgc cdng nghd chuydn nganh cua qudc gia vd khu vuc Ddng Nam A (Bd xdy dung, 2010). Vdi su phat tridn da
nganh nghd tten ddo Phii qudc se dan den nhiing thay ddi tieu cue ve hidn trang su dung ddt, he sinh thai ven bidn va dudi bien, dac biet se anh hudng nghiem trgng ddn mdi tmdng nude ven bien. Vi vdy, de tdi thue hien nham muc tieu iing dung dii lidu viln tham va GIS de quan Iy vd theo ddi su thay ddi he sinh thai ven bien bao gdm; hidn trang su dyng ddt ven bd tten ddt lidn va he sinh thai dudi nude, cac boat ddng nudi ttdng thiiy sdn ven bien de hd ttg vide lap kd hoach ra quydt dinh quan Iy mdi trudng sinh thai ven bidn va quy hoach phat tridn bdn vtrng khu vuc phfa Bdc dao Phu Qudc.
2 PHU'ONG PHAP NGHIEN C t r u 2.1 Vung nghien cuu
Nghidn euu ndy dugc thuc hien phia bdc ddo Phu qudc ttai dai tir 10°14' den 10°27' vT mydn Bdc va tir 103°50' va 104°05' kinh do Ddng.
Bao gdm 3 xa: Cira Can, Ganh Ddu, Bai Thom va mdt phan khu vuc xa Cua Duong. Khu vuc nghidn ciiu chu ydu la khu vuc ven bidn bao gdm phan ddt lidn va phan bidn ven bd each 5 km tfnh tir dudng bd bidn (Hmh 1).
Nuoi ca long be
Hinh 1: (a) Vi tri huyen dao Phu qudc, tinh Kidn Giang, Vietnam; (b) Huyen dao Phu Quoc; (c) Khu vuc Bic dao va cac vj tri nuoi trdng thuy san; (d) Vung ven bit Bdc dao gom ph^n dat lien va phan bien ven bd
each 5 km tinh tir dircmg bir bidn
2.2 Du- li^u vien tham KOMSAT-2. He quy chieu sir dung Id UTM 48 . , , , . . _, i . , • N vd WGS84. Anh LANDSAT TM duoc sii Anh vien tham duoc su dyng gom 4 loai , ^; ^. ,-,. . • - _ - , .i ' . , anh LANDSAT TM, ALOS, THEOS va ^^ng de theo do, hren trang str dung da, ven bo
120
Tgp chi Khoa hgc Tnrdng Dai hge Cdn Tha Phdn .4 • Khoa hge Ty nhiin. Cong nghi vd Mdi tniong: 25 (2013): 119-126 tir nam 2001 ddn 2011. Anh ALOS dugc sii
dung xdy dung va theo ddi phdn bd hien trang ven bd dudi nude. Hai loai anh vien tham do phdn gidi cao gdm THEOS va KOMPSAT-2
dugc su dyng dd xdc dinh hidn trang phdn bd nudi ttdng thuy sdn ven bd. Cdc thdng sd va dac tfnh cua cdc dnh vd linh duoc ttinh bay d Bdng 1.
Bang 1: Cac dac tinh anh LANDSAT, ALOS, THEOS va KOMSAT-2 V ; tinh
LANDSAT TM ALOS AVNIR-2 PRISM THEOS Panchromatic Multispectral KOMSAT-2 Panchromatic Multispectral
Ngay chyp aoh 13/10/2006 28/01/2011 19/12/2007 25/12/2010 16/06/2007 07/10/2010 29/01/2011 10/04/2011 10/04/2011
Tpa dd truDK Viao 10.126 10.125 10.464 10.240 10°37'27"N 10°13' 56"N 10°17'N 10°29' N
tam anh Kinhdd
104.418 104.4575 104.172 103.969 104"10' 27"E 103=51'55"E 103°50' E 104°05' E
9 $ phSn giai anh (tn)
30
10 2.5 2 15
1 4
Ngu6n anh USGS
JAXA
GISTDA
GOSI
2.3 Kiem tra thuc d|a
Kidm tta thuc dia dd danh gia dd chinh xac ciia vide phan lo^i anh so vdi hidn trang ngoai thue dia. Dd tdi da tidn hanh khao sat 50 didm dieu tra hien trang ven bd phdn dat lien, 30 diem eho danh gid hidn trang sinh thai dudi nude va 10 diem cho danh gid nudi trdng thiiy sin. Vi trf cac diem khdo sat dugc xac dinh toa do bdng thiet bi hd thdng dinh vi loan edu (GPS).
2.4 Xii- ly anh
2.4.1 Phdn lich thdnh phdn chinh (PCA) Phdn tfeh thdnh phdn chinh (PCA) Id ky thuat chuydn doi cac gid tti dd sdng didm dnh va su chuyen ddi ndy se nen dir lieu dnh bdng each giu- tdi da lugng thdng tin hihi ich va loai bd cac thdng tin triing ldp ttdn cdc kenh phd anh. Kdt qud la dQ- lieu anh thu dugc (ggi la anh thanh phan chfnh) chiia lugng thdng tin cao d cac kdnh anh tuong quan. Phdn tfeh thanh phdn ehinh dugc su dung de gidm sd Iugng cac kdnh phd khi phdn loai ma lugng thdng tm van khdng bi thay ddi dang kd. Cdng thiic chuyen ddi dugc sii dung &k tfnh todn PCA dua ttdn cdc tdi lieu nghidn cuu cua Khan el al, 1992; Loveland va Sohl, 2002.
Trong nghidn euu nay, 4 kdnh phd cua anh ALOS sir dung de phan tfch thanh phdn chfnh.
Kdnh pho 1 (PCI) vd 2 (PC2) chira Iugng thdng tm eao ndn dugc sir dung tidn hanh phan loai xac dinh hien trang phan bd cd bien ven bd.
Vide phdn loai cd bien dua vao cudng do phdn xa eiia doi mgng trong dd cat cd cudng do phdn xa cao ban cd bien.
2.4.2 Phdn logi dnh
Phuang phdp phan loai iang gidng gan tdi uu (Maximum Likelihood Classifier - MLC) dugc ap dyng dd phdn loai dnh ttong nghidn eixu nay.
Phuong phap phan loai gdn diing duge xdy dung dua tren co sd gid thuydt ham mat dg xac suat tuan theo ludt phdn bd ehudn. Mdi pixel dugc ti'nh xac sudt thudc vdo mdt nhdm ndo dd va duge chi dinh gdn tdn nhdm ma xac suat thugc vao nhdm dd la ldn nhdt.
Anh LANDSAT nam 2006 va 2011 dugc phan loai thanh nhieu Idp ddi tugng xdy dung ban dd hidn trang dua tren phuong phap phdn loai nay. Cdc nhdm ddi tugng chfnh bao gdm ddt rimg, ddt ndng nghidp, ddt than bun vd ddt xdy dung dugc phdn Io?i thanh cac nhdm hidn trang dai didn tai khu vuc nghidn cihi. Anh ALOS ndm 2007 va 2011 sau khi phdn tich thdnh phan chfnh dugc phan logi dtk xac dinh hidn trang phdn bd cd bidn tai viing nghien ciiu.
Tgp chi Khoa hgc TntdngDgi hoc Cdn Tha Phdn A: Khoa hoc Tunhiin, Cdng nghi vd Moi tru&ng 25 (2013): 119-126
2.4.3 Tich hop dnh
Ddy la mdt trong nhimg ky thudt dugc dp dung dd tfch hgp cdc chi tiet hinh hgc ciia hai hinh dnh, mdt cd do phdn gidi cao dnh loan sdc (PAN) va mgt do phan giai thdp dnh da phd (MS), kdt qua dnh tich hgp la dnh da phd (MS) do phdn giai cao. Trong nghidn cuu ndy, ky tiiudt tich hgp dugc dp dyng cho anh THEOS vad KOMPSAT-2. Anh THEOS MS (15 m) dugc hgp nhdt tir dnh tt)an sdc THEOS PAN (2 m) xay dung thdnh anh THEOS MS (2 m) va anh KOMPSAT-2 MS (4 m) duge tfeh hgp tir dnh loan sdc KOMPSAT PAN (1 m) xdy dung thdnh dnh da phd KOMPSAT MS (1 m). Anh sau khi tieh hgp sd dp dyng phuang phdp phan loai ddi tugng de xac djnh cae khu vuc nudi thiiy san.
2.4.4 Phdn logi doi tugrng
Anh vien thdm sau khi dugc tham chidu he toa do thyc, cdc doi tugng dugc lua chgn cho phuang phap phdn loai ddi tugng la nhiing ddi tugng ttdn dnh cd dang hinh dong nhdt (hinh vudng hay hinh chii nhdt). Trong nghidn cuu nay, sii dyng cac quy tdc dua trdn cdc thudc tfnh doi tugng gdm d^ng viing, do chat, kfch thudc, ty Id kdnh phd vd miic do trdt tu sdp xdp dd loai bd mgt sd ddi tugng nhieu khdng mong mudn hay phan dat lidn hoac ddi tugng nude. Anh THEOS vd KOMPSAT duge sir dung dd phdt hien ddi tugng, phuang phdp phdn loai ddi tugng theo hudng duge dp dyng ddi tugng nudi
trong thuy san gdm nudi cd Idng be va nudi dc huong ddng Idng tai khu vuc nghidn ciiu.
2.5 Thay doi hien trang
Ky thu^t va cac thudt toan phat hidn su thay ddi d cac giai doan khac nhau ciia cac doi tirgng tten anh vidn tham da dugc thidt lap dua tren su phat tridn cdng nghd vidn tham v^ cac ddc tfnh khdng gian, phd, nhidt va thdi gian. Hai phuong phdp phd bien phat hidn sy thay ddi trdn dii iidu dnh ve tinh dd la so sdnh su khdc biet ttdn anh va sau phdn loai (Singh, 1989). Trong nghidn eiiu nay, phuang phap so sanh sau phan loai dugc dp dung de ^hat hidn thay ddi hien trang su dung ddt ven bidn va dd che phu cd bidn. Hai cap anh dugc sii dyng de phdn tfch thay ddi g6m cap dnh LANDSAT nam 2006 va 2011 theo ddi thay ddi hien ttang ven bidn; cap anh ALOS nam 2007 va 2010 theo doi thay ddi cd bien.
3 K E T QUA THlTC H I £ N 3.1 Phan bo hien trang ven bien
Ket qua phdn loai hidn ttang ven bien khu vyc nghien ciiu dugc trinh bay trong Hinh 2.
Hidn ttang ven bidn nam 2006 va 2011 gdm 5 nhdm ddi tugng la ddt rimg, ddt rimg ttam, ddt ndng nghidp, ddt than biin va ddt xdy dung.
Didn tfch ddt rung che phu cao nhat chiem 69,26% tdng dien tfch; ke ddn la ddt ndng nghiep vdi ban 14%; dat than biin vd ddt rimg ttdm chiem khoang tir 6 den 7,5%; va cudi ciing la ddt xay dyng lit 1 - 3% tdng didn tfch.
(a) Hidn trang ndm 2006 (b) Hidn ttang nam 2011 Hinh 2: Hien tr^ng ven bien nam 2006 va 2011
Tgp chi Khoa hgc Tru&ng Dgi hoe Cdn Tho Phdn A- Khoa hge Ty nhiin. Cdng nghi rd Moi tnr&ng. 25 (2013): 1'"'' 3.2 Thay ddi hien trang ven bien
Hdu hdt ddt ndng nghiep va ddt rirng tram da chuyen thanh dat xay dung ca ban giai doan tir 2006 ddn 2011. Dien tfch gidm ciia dat ndng nghidp 211,19 ha (30,86%) vd rimg tram la 159,87 ha (23,36%). Dien tich ddt xay dyng da tang 349,89 ha chidm khodng 51,13% tdng didn tfch ddt thay ddi trong giai dogn nay (Hinh 3).
Cac viing ddt ndng nghidp gdm cdc lo^i cay ttdng Idu nam nhu lieu, hat dieu, dira ttdng va cdc loai cay trdng ngdn ngdy nhu rau mau, khoai mi. Cdc lo?i cay ttdng ndy vd rimg tram deu mang Iai thu nhdp thdp, do gia cd khdng on dinh va chi tidu thy ndi dia cho ndn didn ti'ch dat ndng nghidp va ttam gidm di chuydn sang muc dich su- dung khac cd thu nhdp cao ban. Ngugc
Iai, ddt rimg va ddt than bun thay doi rdt ft boi vi ca hai loai dat nay duge bao v? dd phyc hoi cae he sinh thai tut nhien. Riing Phu Quoc tap tmng chu yeu d phfa Bdc va Ddng Bdc dao, rimg dugc khoanh viing bao vf nghidm ng?t de bao t6n vd phat ttidn ngudn giong vd da d^ng sinh hgc. Ben canh dd, viing ddt than bCin la nhiing ddc khu sinh thai vdi dgng v$t, thuc vdt da dang. Theo T 6 ehiic rimg ngap man quoc td (Organization Wetlands Intemational), cac khu vuc than biin cd tdm quan ttgng Idn ttong tu nhien, rimg phat ttien tu nhien, didu hod khf h^u, luu tru- ngudn carbon, luu trii nude vd gidi ban do man, bdo tdn ngudn gen quy hiem cua cac lo^i thuc vat va ddng vdt ddc bidt la dnh hudng eiia bidn doi khf hdu.
Hinh 3: Ban dd thay ddi hidn trang (2006-2011)
Hinh 4: Ph^n trSm di^n tfch d^t thay dSi
(2006-2011) f 000
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| a X i : c n ? a y i&a>3CUS-28n I 3.3 Hien trang co bien va si^ thay doi hifn
trang co bien
Hien n^ng co bien phan bo ven ba phia Dong B k dao Phu Qu6c. Sir phan b5 cua co biln nam 2007 va 2010 duoc thS hien trong Hinh 5. Tit nam 2007 iin 2010 dien tich c6 biJn tang len dang kl tir 10.985.84 ha nam 2007
tang Ien 12,869.83 ha nam 2010. C6 biSn o Phu Qu6c dugfC bao ton nghiem ngat nham duy tri da dang sinh hoc bien va moi tnrong s6ng cho cac loai thuy sSn nhu nguon thiic an, con giong sinh s6ng ya phat trien (Nguyen, 2011) do do tham CO biSn trong khu virc nghien cihi da tang dien tich 16n dang kS trong giai doan nay.
Tap chi Khoa hoe Tru&ng Bgi hgc Cdn Tho Phdn A- Khoahoc Tunhiin. Cong nghi vd Moi tnrdng 25(2013) 119-126
• • • Kuocbwn
(a) Hidn ttang cd bidn ndm 2007 Hinh 5: Hien trang pban 3.4 Danh gia do tin c^y
Vide danh gia do tin cay phdn loai hidn trang ven bien sii dyng anh LANDSAT ndm 2006 va 2011 da dugc thuc hidn dua ttdn 50 didm khdo sdt thyc dia vao nam 2011 d6ng thdi dya vdo cac ban do hidn trang huyen dao Phu Qudc (Bg xdy dung. 2010) cung nhu cac tai lieu cd lidn quan de xdc dinh do chi'nh xac phan loai anh timg giai doan. Dd chfnh xac phdn loai ^ n g thd nam 2006 la 84,62% vd nam 2011 la 80,77%.
H^ so thdng kd (kappa) tdng thd ndm 2006 la 0,85 va nam 2011 la 0,76. Ddi vdi dnh ALOS phdn lo^i cd bidn nam 2007 va nam 2010 dugc thyc hidn dua trdn 30 didm khdo sat thgc dia vd ket qud phdn bd hien ttang ed bidn da thyc hien vao ndm 2007 (Minh, 2008) va cdc tdi lieu nghien cuu ve doi mgng ven bd dudi nude vao cdc nam 2007 va ndm 2010. Do chfnh xdc phdn loai tdng thd ndm 2007 la 91,30% va nam 2010 Id 86,96%. He sd thong ke (kappa) tdng the ndm 2007 la 0,89 va 2010 la 0,84. Vdi do chfnh xac phan lo^i cho thdy mue dp tin cdy cao khi phdn loai hidn trang ven bidn sir dyng anh LANDSAT va phdn loai cd bidn sii dung
Clwain
^ B C6bi£ii_
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(b) Hidn t r ^ g cd bidn nam 2011 bd CO biln ndm 2007 va 2010
anh ALOS.
3.5 Phdn bd hien trang nudi trong thiiy san Trong nghien euu nay, 2 ioai dnh KOMPSAT va THEOS do phdn giai cao dugc sii dyng cho vide phan loai nudi trdng thuy sdn ven bidn. Do dnh KOMPSAT-2 khdng che phd loan viing nghien ciiu ndn dd tdi da bd sung su dyng anh THEOS xac djnh vi trf nudi ca long be.
3.5. J Vi tri nuoi dc huang ddng long Kdt qua sau khi tieh hgp dnh vd tinh KOMPSAT-2 dugc thd hidn tren Hinh 6 (a), day Id dnh da phd cd do phan gidi cao 1 m, kfch thudc ludi dang nudi dc huong la 2x8 m hoac 2x10 m luj; theo chidu ddi ludi, ndn vj ttf ddng long nudi dc huong tai khu vuc nay cd thd xdc dinh duge thdng qua dnh vidn tham. Bdn do vi ttf nudi de huong dugc trinh bay d Hinh 6 (b).
Sd lugng dc huong nudi ludi dang tai khu vuc nghidn ciiu khoang 10 ludi dang, do thdi gian chup anh vao thdng 4, dc huong dang vdo giai doan nhihig thang ddu chudn bi tha nudi ndn sd lugng ludi dang dao ddng cdn it.
(a) (b) Hinh 6: (a) Anh KOMPSAT-2 da pho 1 m, (b) Vi tri phdn b6 6c hmmg dang long
Tgp chi Khoa hge Tru&ngDgi hgc Cdn Tha Phdn .4 Khoa hge Ty nhien. Congnghi vd Mdi irir&ng: 25 (20l3) 119-126
3.5.2 Vi tri nuoi cd bop long be
Kdt qud sau khi tfch hgp dnh ve linh THEOS dugc thd hidn ttdn Hinh 7 (a), ddy la anh da phd cd do phan giai cao 2 m, do kfch thudc Idng be nudi ca bdp la 4x4 m ndn vi tri long be nudi ca bdp cd thd xac dinh dugc trdn anh tai khu vuc nay. Vide gidi doan anh dua vao phuong phdp phdn tich ddi tugng (OBIA) dk phdt hien nudi ca bdp Idng bidn. Didu nay dugc chiing minh Id phii hgp de phdn loai cho dnh ed do phdn giai cao (Kumar, 2007). Trong nghidn ciru nay, viec phdn loai dua tten nguyen tdc trich Igc cac Idn^
bd d khu vue nudi. Kdt qud phdn loai dugc the hien d Hinh 7 (b).
Hinh 7: (a) Anh THEOS da pho 2m, (b) Vi trf phan b6 ca long be
3.6 Ban do phan bo hien trang 2 viing sinh thdi ven bien
Dua vdo kdt qua phan loai hidn trang ven bien d muc 3.1, 3.3 va 3.5, lien hanh xay dung bdn do phan bd hien trang 2 vimg sinh thdi ven bien Bac dao Phu Qudc gdm ba nhdm hien ttang chfnh la: hidn ttang ven bd phdn ddt lidn, hi?n trang cd bidn dudi nude vd nudi trdng thiiy
Dgc theo vung ven bidn dao Phii Q^oc, eo nhidu lodi nudi thiiy^ sdn bidn cd gia tti thuong phdm cao tron^ dd dc huang nudi ludi ddng ya cac b6p nudi Idng be. Ddy la cac lodi thuy san mang lai Igi nhudn cao cho cac hg ddn nuoi thay sdn. Tuy nhien, chat thai t& cac loai nudi nay la mdt ttong nhiJng ngudn dnh hudng true tiep den mdi tmdng nude, chat lugng nude va he sinh thdi bidn. Su gia tang hifn tr?ng nghe nudi ndy se tmc tidp dnh hudng ddn mdi tmong sdng, ngudn tai nguydn thidn nhien, mdi tmang sdng va chat lugng mdi tmdng nude khu vyc ven bd.
(a) (b)
san (Hinh 8). Hien trang sir dyng dat ven bd gdm 5 nhdm ddi tugng nhu: dat riing, ddt riitig ttam, ddt ndng nghidp, ddt than biin va dat xdy dung. Hien ttang nudi thuy sdn g6m 2 loai doi tugng cd bdp Idng phdn bd phfa Bdc ddo thugc ap Rach Vem vd nudi oe huang phdn bo d phfa Ddng Bdc dao thudc ap Cay Sao.
Nudi oe huong ludi c Hinh 8: Ban 6h phdn bo hifn tr^ng 2 viing sinh thdi ven bien Bdc dao Phd Qu6c
Tgp chi Khoa hge Tni&ng Dgi hoc Cdn Tha Phdn A. Khoa hoc Tu nhien, Cong nghe vd Moi Irudng: 25 (2013): 119-126
4 K E T L U I N
Thdng qua ung dung eua anh yd tinh vidn tham, dh tai da xac dinh phan bd hien ttang vung ven bidn (viing ven bd va dudi nude) dong thdi theo ddi sy thay ddi cua he sinh thai ven bien phia Bac dao Phii Qudc cu thd dya ttdn 4 loai anh vien tham nhu sau:
- Anh LANDSAT dugc sii dung dd xac dinh phdn bd hien ttang viing ven bd phdn ddt lien vd anh ALOS dugc su dyng dd xac dinh phdn bd hidn trang cd bidn dudi nude ven bd giai doan ndm 2006 va 2011; dnh THEOS va KOMPSAT la 2 loai anh cd do phan gidi cao dugc sii dung de xac dinh vimg phan bd ea bdp nudi Idng be vd dc huong ludi dang, do kfch thudc long be (4x4 m) va ludi ddng (2x10 m) tuong ddi nhd nen da phdi sir dung dnh vien tham cd do phdn gidi cao.
Trong giai doan tir 2006 ddn 2011, ddt ndng nghiep va ddt riing tram da chuydn ddi phdn ldn sang dat xdy dung vdi dien tich 349,89 ha chidm 51,13% ttdn tdng dien tfch ddt thay ddi. Didn tich thdm cd bidn da tang trong giai doan khdo sat tir nam 2007 den 2010 Id 1.883,99 ha.
Ky thudt vien tham va cdng nghd GIS da dugc chiing minh hieu qua ttong vide thu thdp quan Iy va xir Iy diJ lidu ttong cdng lac quan ly tai nguydn va ed thd dugc dp dung cho gidm sdt mdi trudng ven bidn eung nhu phdn tfch cdc xu hudng vd udc tinh nhihig thay ddi cd thd xay ra.
De dam bdo phdt tridn ben vung, vide su dyng anh vien thdm va dp dyng cdc phuang phdp xii ly anh ket hgp ky thudt GIS la cdn thidt dd cap nhat du' lieu vd mdi ttudng sdng, cac vung bao tdn, danh gia chdt lugng nude cho cac khu vyc nghidn cuu viing ven bd.
TAI LIEU THAM KHAO
1. Bd xay dung. 2010. Thuydl minh long hgp.
Dieu chinh quy hoach chung xay dung dao Phii Quoc tfnh Kidn Giang den nam 2030. Vidn Kidn Tnic, Quy hoach do thi va nong thdn. TP.
Hd Chi Minh, 06/2010.
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4. Nguyen, T. (2011). Nghe nuoi 6c huong ttdn dao Phii Qudc phat trien thidu ben vimg. Bao Cdn Tho. 17/07/2011.
5. Phong kinh Id huyen Phu Qudc. 2008. Cac bao cao tong ket nong iam ngu va tinh hinh kinh id huyen Phu quoc. Cac bao cao hang nam.
6. Ton Binh Minh. 2008. Mapping changes in the marine environment of Phu Quoc Island, Viet Nam. A thesis submitted in partial fijlfiliment of the requirements for the degree of Master of Engineering in Remote Sensing and Geogr^hic Information System. School of Engineering and Technology Asian Institute of Technology, Thailand. April, 2008.
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