Tap chi Khoa hoc va Cong nghe bien TIO (2010). Sd 2. Tr 63 - 75
M O HINH QUAN LY VA PHUC HOl THAM CO
BIEN6 HUYEN NUI THANH, TINH QUANG NAM
'-'-"•"•'• NGUYEN HUtJ DAI
Vien Hai duong hoc
Tdm tdt: 10 hecta thdm co bien cf xd Tam Giang, huyin Niii Thdnh, tinh Qudng Nam da duac chon vd duac UBND tinh Qudng Nam ky quyet dinh so 1938/QD-UBND ngdy 09
•thdng 6 ndm 2008 giao cho du dn "Qudn ly tong hap dai ba Qudng Nam " de thuc Men mo hinh trinh dien phuc hoi he sinh thdi co bien. Ddy Id viing trung tdm phdn bo cua co bien a dam An Hoa, Niii Thdnh vai su uu the cua loai co Luan Zostera Japonica, do bao phu co noi dgt 25-50%, nhung hien nay dang bi suy gidm nhanh do cdc hogt dong khai thdc hdi sdn co . ., tinh huy diet. Mo hinh trinh diin duac thuc hien nha su ho tra cua chinh quyen dia phucmg, , nhom hgt nhdn gom 4 ngu&i vd cong dong cu ddn dia phuang. Co Luan da duac di trong phuc hoi theo phuang phdp PU (bimg luon trdm tich vd co). Kit qud kiem tra buac ddu sau 6 tudn di trong cho thdy mat do thdn dimg co Luan tdng 13%. Viec van hdnh mo hinh duac de nghi trin ca sa gdn kit lai ich ciia viec khai thdc hap ly vd bin vOng nguon lai trong hi sinh thdi CO biin vai viic qudn ly vd bdo ve chiing.
'^ L MO DAU
Cac ket qua nghien ciiu cac tham co bien d Viet Nam da cho thay rieng d -viing ven bien va cac dao ven bd cac tinh phia Nam cd bien phan bd thanh cac viing rdng ldn hang tram hecta nhat la d cac tinh Quang Nam, Phu Yen, Khanh Hda, Ninh Thuan, Binh Thuan, Viing Tau Cdn Dao, Phii Qudc ...Cac tham cd bien nay dang dam nhiem vai trd quan trgng ddi vdi mdi tradng va sinh vat, la noi cu tni sinh vat da dang, noi nudi dudng au the ciia nhieu loai sinh vat va cung cap giong cho cac -viing bien lan can (Nguyen Hiiu Dai &
CS 1999, 2000). Tuy nhien day la noi dang xay ra manh me cac hoat ddng nudi trdng va khai thac qua mite hoac cac each danh bat cd tinh huy diet ciia cu dan ven bien. Cac hoat ddng nay da lam cho cac tham cd bien bi suy giam manh hoac mat di. Chi rieng d -vimg bien Khanh Hoa trong 5 nam qua da cd khoang 30%) dien tich cac tham co bien da bi mat di hoac suy giam nghiem trgng (Nguyen Hiiu Dai & CS 2002). Su mat di ciia cac tham cd bien lam mat di noi cu tni sinh vat, ddng thdi dan den suy giam chat lugng mdi tradng ciing nhu tinh da dang sinh hgc va ngudn lgi.
6 tinh Quang Nam, cac ket qua khao sat cua chiing toi da cho thiy cac tham cd biln
chilm gin hit viing biln ndng ven bd viing An Hda, Nui Thanh vdi su uu thi ciia 3 loai cd bien: cd Luon Zostera japonica, cd He Halodule uninervis, va co Xoan Halophila ovalis.
Tuy nhien, cac tham cd nay dang bi suy giam nhanh, la he qua cua cac hoat ddng khai thac khdng hgp ly. Xiet dien ciing vdi nghe cao day va dao bit hai san da lam suy giam nghiem trgng he sinh thai cd bien, sinh vat non bi bat hoac chet, con co biln bi cao, nhd khdi trim tich va trdi dat khap noi. Viec quan Iy va bao ve chiing la rit cip thilt trade khi tham co nay bi mit, va de phuc hdi la rat ton kem va khd khan.
Tham khao cac tai lieu tinh toan ve viec phuc hoi cac tham cd bien d -vimg on ddi (vi du vdi cd Luan Zostera), phai mat tit 9.000 den 46.000 USD/hectf. bing each dung phuong phap lay ludn tram tich va cd. Neu dung phuong phap lay ;han ngam va than diing, phi ton tit 11.000 din 74.000 USD/hecta (Spurgeon, 1998). Bao cao cua chuang trinh hanh ddng Qudc gia ve da dang sinh hgc cua Anh Qudc ciing da cho biet gia ca de phuc hdi cd bien d day la 8.600 USD/hecta va khoang 1000 hecta da dugc di trdng phuc hdi (Spurgeon 1998). Do vay viec quan ly va bao ve phai dugc uu tien thuc hien, neu khong, khi cac tham cd bien bi mat di thi viec phuc hdi rat tdn kem va khd khan.
II. TAI LIEU VA PHUONG PHAP NGHIEN ClTU
Bai viet sit dung cac so lieu ciia md hinh quan ly va phuc hdi cd bien xa Tam Giang, Niii Thanh, thudc du an Quan ly Tdng hgp ddi bd Quang Nam, thuc hien tu nam 2006 den 2008.
'' Khu vuc dugc chgn de tien hanh md hinh la viing trang tam phan bd ciia cd bien d Xa'Tam Giang, dam An Hda, noi ma he sinh thai cd bien cd tinh da dang sinh hgc cao. ''
Tien hanh danh gia cau tnic tham cd bien trade khi thuc hien md hinh. Sit dung phuang phap mat cat, thuc hien theo Quy pham dilu tra biln, phin thuc vat biln do Uy ban Khoa hgc va Ky thuat Nha nudc ban hanh (1981) va cac phuang phap trong "Hudng din dilu tra ngudn lgi biln nhiet ddi" ciia English, Wilkinson & Baker (1994) va "Cac phuong phap nghien ciiu vl cd biln" cua Philips & McRoy (1990). Theo do cac mat cit dugc thuc hien mdt each ngau nhien sao cho chiing cd tinh dai dien cho hien trang cd bien -vung khao sat. Tren mdi mat cit cd 3 tram thu mau dl tiln hanh cac khao sat vl thanh phan loai, mat do, do bao phii, sinh lugng, thudng la mdt tram d -viing phan bd tren, mgt d -viing phan bd giiia va mgt d dai phan bd dudi ciia khu -vuc phan bo tham cd bien. BChung sinh lugng cd dien tich 0,25m^, dugc chia thanh 25 d nhd Idm^. Tai cac khung nay do bao phii cua cac loai cd biln dugc tinh trong timg d nhd va sau dd tinh chung cho khung 0,25m
^ theo phuang phap ciia Saito & Abe (1970).
Ky thuat trdng phuc hdi cd biln dugc ap dung tit cac kit qua nghien ciiu trong phdng thi nghiem (N. H. Dai, 2005). Loai co biln uu thi va dugc di trdng phuc hdi d day la cd Luon (Zostera japonica) la loai uu thi tai dia phuang, cd kich thudc nhd va sinh san chii yeu bang hinh thiic sinh san dinh dudng. Ap dung dac diem nay, sit dung ky thuat lay giong cd ciing vdi phin tram tich (PU - Planting Unit). Cac khung thep hinh tru cd tiet dien 14cm dugc sit dung lam dung cu de lay cac bui cd bien. Nguon gidng dugc thu thap tu cac -viing lan can, noi co bien cd tinh trang siic khde tdt, do bao phii trang binh tit 75 - 100%, miic do cho phep liy 20% (N. H. Dai, 2005). Mdi bui cd giong cd mat do hi 200 - 250 than diing.
Cac bui CO gidng nay sau do dugc trdng trong cac hd cd kich thudc bang vdi nd, hang each hang 50 cm. Ky thuat di trdng dugc tap huan cho nhdm hat nhan thuc hien md hinh va cdng ddng dan cu dia phuong. De kiem tra su thich nghi phat trien ciia cd bien di trong da bd tri 3 Id thi nghiem, moi Id gom 10 bui cd cd mat do than diing ban dau dugc kiem soat nhu nhau.
Sau 6 tuan di trdng mat do cd d cac Id thi nghiem dugc danh gia lai.
III. KET QUA
1. Chon lua dia diem trien khai mo hinh phuc hdi Cac tieu chi chon dia diem
Viec lua chgn diem trinh dien phuc hdi dugc thuc hien theo cac tieu chi nhu sau:
- Cd tinh da dang sinh hgc cao, la viing phan bd quan trgng ciia cd bien.
- Cd vai trd quan trgng ddi vdi mdi tradng va ngudn lgi sinh vat ciia mgt khu -vuc - Dang bi suy giam
- Dugc su ung hg ciia chinh quyen dia phuang va su dong thuan ciia cdng ddng.
Khu vuc thu nghiem phuc hdi
Ap dung cac tieu chi tren, -viing dugc chgn nam d thdn 1, 2 xa Tam Giang, dien tich trien khai khoang 10 ha cd hinh chii nhat (hinh 1). Khu -vuc trinh dien quan ly va phuc hdi CO bien dugc thuc hien do quyet dinh sd 1938/QD-UBND ngay 09 thang 6 nam 2008 cua UBND tinh Quang Nam. Vi tri tga do tai 4 diem gdc la:
- 1 0 8 ° 4 1 ' 5 8 , 6 " v a l 5 ° 2 9 ' 2 8 , 7 " - 108°41'58,6" va 15°29'28,7"
- 108°41'30" v a l 5 ° 2 9 ' 5 7 " - lOS''39'41,8" va 15°28'07,5"
- 108^41'55,8" v a l 5 ^ 3 0 ' 1 3 " - 108*^39'37,2" va 15°28'57,2"
- 108^41'19" v a l 5 " 2 9 ' 4 7 " - 108°39'19,8" va 15°28'06,3"
B I E N D O N G
GHI CHO
VOng phSn bffco bi^ri VOng tri^n khai rnfl hinh phoc h6i
'I
rf
^^^\
>
'—^
^
i
*Hinh 1: Khu -vuc trien khai md hinh phuc hdi cd biln (xa Tam Giang, Nui Thanh)
Khu vuc nay la viing phan bo tu nhien ciia cd biln, trai dai theo ven bd, dai 500m,
rdng 200 met. Day la -viing phan bl quan trgng ciia cd biln d xa Tam Giang. Tham cd nay
hien nay dang bi suy giam khoang 30%) do cac hinh thiic danh bat va khai thac cd tinh hiiy
diet, nhilu khoang trdng do cd bi chit. Trong khu -vuc nay, tien hanh di trong phuc hoi khoang 1 hecta, tap trang vao -viing bi suy giam manh hoac bi chet, phan cdn lai dugc khoanh -viing quan ly, cham soc va bao ve.
Chat day chii yeu trong -viing nay la cat pha bun, cd lan nhieu xae vo so dc, nen day bang phang, vao thdi gian trieu thap nhat, thudng ngap nudc tit 0,2 den 1 met. Do man do dugc tit thang 10-12 (miia mua) nam trong khoang 15 - 20%o, thich hgp cho viec phat trien ciia cd bien. Nhiing khi mua ldn keo dai, do man cd the thap hon nhung thdi gian khong lau.
Do tinh da dang sinh hgc cao va nguon lgi phong phii, day la khu -vuc thudng xuyen dugc ngu dan khai thac bang dii mgi hinh thiic tit each lugm nhat thd so cho den xiet dien, ludi cao hoac cac each khai thac cd tinh pha hiiy noi cu tni nhu dao xdi bat triing bien hay ngao so. Tat ca eae hoat dgng ke tren deu gay suy giam hoac mat eac tham co. Chiing phan bd thua, da beo, nhieu khoang trong. Nhieu ngudi dan cho biet trade day mat do co rat day, chieu cao la thudng dai hon 20 cm.
2. Hien trang cac tham cd bien d vimg Niii Thanh, Quang Nam
• Niii Thanh la khu -vuc phan bd quan trgng ciia co bien d phia nam ciia tinh Quang Nam, dien tich phan bd khoang 200 hecta, chii yeu tap tmng d dam An Hoa, khu -vuc -viing trieu ven bien thudc dia ban cac xa Tam Giang, Tam Hai, Tam Quang, (huyen Niii Thanh).
Cac tham cd bien nay bao phii hau het cac -viing nudc ndng, cac cdn gd, tit muc trieu thap den sau 0,5-2 met, ngoai trit cac laeh sau.
3 loai CO bien thudng gap la - Cd Luon Zostera japonica - Co Xoan trdn Halophila ovalis - Co He Halodule uninervis
Rieng -viing Ban Thang (xa Tam Hai, Nui Thanh) tham co bien con c6 them cac loai:
- Co Vich Thalassia hemprichii
- Cd Xoan la dai Halophila decipiens phan bd tit do sau 3 - 4 met trd xudng.
Tham cd bien trong dam An Hda tuong ddi kha dong nhat. Loai uu the nhat la cd Luon phan bd khap mgi noi, ke ca trong cac ao dia nudi tdm. Chiing cd chieu cao than dimg tir 1 0 - 2 0 cm. Nhieu ngu dan cho biet trade day chiing cao den 30 - 40 cm (giong vdi tham cd d Cita Dai, Hdi An) nhung nay can coi va ngan hon. Loai co Xoan la trdn mgc xen ke vdi loai tren va phat trien uu the d viing dudi trieu ludn ngap nude. Ngoai ra trong cac ao dia bo hoang cdn gap co Kim Ruppia maritima.
Do do man trong dam An Hda hiong doi it thay dii trong mua mua hoac chi bi nggt hda trong thdi gian ngan khi xay ra lu ldn cho nen ciu tnic ciia cac tham cd biln it thay ddi theo miia. Sau day la kit qua cac chuyin khao sat ciu tnic cac tham cd quan trgng trong dim An Hda vao thang 9/2007 (cuoi miia khd) va thang 01/2008 (cudi miia mua).
Bang 1: Cau tnic ciia cac tham cd bien d mgt sd viing phan bl tap tmng d dim An Hda, Niii Thanh thang 9/2007 va thang 01/2008
Dia diem
Long Thanh Dong xa Tam Hai
C 6 n S i ( l ) XaTam
Giang Con Si (2)
XaTam Giang Gan cang, Tam Giang 1
Tam Giang 2
Tam Giang 3
Thon 2 Tam Giang Thon 3 Tam Giang
Toa do
15°28'308 108°40'475
15°28'935 108°39'248
15°28'879 108°38'962
15°28'558 108°39'402
15°28'618 108°39'740
15°28'274 108°39'607
15°28'009 108°39'810
15°27'863 108°39'790
Ten loai
CO
Co He Co Xoan
tron Co He
Co Luon Co Luon Co Xoan
tron Co Luon
Co Luon Co He
Co Luon Co Xoan Co Luon
Co Luon Co Xoan
tron
Mat do (cay/m^) 9/07
980 230 11.20
0 820 9800
1200 12.50 0 11.60
0 6200 7800 5800 13.20 0 12.40
0 2.800
01/08
820 300
2.600 7.200
8.800 420
11.000
8000 600
7600 5200
12.200
11.000 2.200
Do bao phu (%)
9/07
<6,25
<6,25
25-50
<6,25 25-50 6,25-
12,5 25-50 25-50 6,25-
12,5 12,5-25
6,25- 12,5 25-50 25-50 6,25-
12,5
01/08
<6,25
<6,25 6,25-
12,5 12,5-25
25-50 6,25-
12,5 25-50
25-50
<6,25 12,5-25
6,25- 12,5 25-50 25-50 6,25-
12,5
Sinh luffng (g kho/m^) 9/07
76 58
248 84
201 76
287
262 98
88 64
284
272 42
01/0 8 46 22
78 104
191 26
221
170 38
86 60
244
232 35
Kit qua tren cho thiy vao mua ning (9/2007) va vita hit miia mua (01/2008) cau tnic ciia cac tham cd biln d Niii Thanh it thay ddi. Cac tham cd bien d day vin eo tinh trang tdt vao cudi mua mua. Vao luc nay mat do cd bien cd giam va chieu cao ciia cd ngan hon (trang binh khoang 10 cm).
3. Danh gia c§u true tham cd bien khu vuc trien khai mo hinh
Bang 2: Ciu tnic tham cd bien khu -vuc trien khai mo hinh (thang 4/2008) Mat
cat
1
2
3
4
5
Khung sinh luong
1.1 1.2 1.3
2.1
2.2 2.3 3.1
3.2 3.3 4.1
4.2 4.3 5.1 5.2 5.3
Ten loai cd Cd Luon
CdHe Cd Luon
CdHe Cd Luon
CdHe Cd Luon Cd Xoan trdn
0 Cd Luon
CdHe Cd Luon Co Xoan trdn
Cd Xoan Cd Luon Co He Cd Luon Cd Xoan trdn
0 Cd Luon Cd Luon Cd Xoan trdn
0
Mat do (cay/m^)
12.500 1.700 14.200
3.200 11.600
6.200 13.400
700
10.300 5420 12.600
4620 1200 11.840
4800 13.260
2200
12.800 9700 3320
Do bao phu (%)
25-50
<6,25 25-50
<6,25 25-50 6,25-12,5
25-50
<6,25
25-50 6,25-12,5
25-50 6,25-12,5
<6,25 25-50 6,25-12,5
25-50
<6,25
25-50 12,5-25
<6,25
Sinh lucmg (g khd/m^)
231,16 32,32 288,51
37,30 262,20
98,30 314,25
27,10
223,70 36,38 334,50
40,10 22,18 233,50
36,30 272,18
18,21
229,15 172,40 32,10
Khao sat danh gia hien trang ciu tnic tham cd biln trade khi tiln hanh thuc hien md hinh. 5 mat cit ngang qua viing 10 hecta ciia md hinh phuc hli. Tren mdi mat cit liy ngiu nhien 3 khung sinh lugng theo thii tu 1, 2, 3 tit trong bd ra -viing luon ngap nudc.
c i u tnic tham cd bien qua 5 mat cit ngang qua khu -vuc 10 hecta quan ly cd bien theo thii tu tit phia Bac xuong phia Nam dugc the hien qua bang sau:
Kit qua cho thay tit viing trieu tmng binh den viing trilu thip, do bao phu co bien tuong dii cao, cd noi dat hi 25 - 50%). Nhung tit viing trieu thip din vimg ngap nudc 0,5 -
1 met khi trieu thap nhat cd bien bi mat hoac suy giam nhieu. Nguyen nhan la do d -viing ludn ngap nudc, cac hoat ddng danh bat bang ludi cao, xiet dien lam chet cd. Danh gia chung dien tich cd biln bi mat di hay suy giam tmng binh trong khu -vuc 10 hecta quan ly nay la khoang 30%. Viec danh gia nay la can thiet de kiem tra tac dgng ciia viec quan ly bao ve va di trdng phuc hdi ddi vdi tham cd bien.
4. Di trong phuc hdi
Trong 10 hecta khu -vuc quan ly, 1 hecta d -vung tmng tam dugc chgn de tien hanh trien khai md hinh di trdng phuc hdi. Khu -vuc nay dugc rao ludi xung quanh.
Nhom hat nhan va cong dong dan cu dia phuang da dugc tap huan ky thuat di trong.
De thuan tien va cd hieu qua, cdng viec dugc tien hanh vao thdi diem thiiy trieu xuong thap, thudng la budi chieu. Trong qua trinh thuc hien (thang 9 - 10/2008), cu dan trong
•viing rat quan tam va hg mong mudn dugc phep nhan rdng md hinh nay ra xung quanh.
Bang 3: Phat trien mat do than diing cua cd Luon di trong d 3 Id thi nghiem
Ten loai cd
Cd Luon Nhat Zostera japonica
18/10/08 (bat diu di trong, mat do ban dau giong nhau d cac Id
thi nghiem) Thi nghiem
(TN) 1 (10 bui)
200 than dimg/bui
T N 2 (10 bui)
200 than dimg/bui
T N 3 (10 bui)
200 than diing/bui
Mat do trung binh than dung ciia cac bui cd con song sdt (03/12/08)
T N I
227,14
±36,83 (Sd bui cd cdn song: 7)
T N 2
231,66
±24,83 (Sd bui cd
cdn song :6)
TN 3
224,75
±35,57 Sd bui cd cdn sdng : 8)
IJ D I kilm tra va danh gia sir thich nghi, t i n tai, ciing nhu su phat triln ciia cd biln di trdng cd nhilu phuang phap: tang tradng chiiu dai la, nang suat la, mat do, do bao phii.
Viec chgn lua phuong phap hiy thuoc vao hing loai cd bien va thdi gian thit nghiem.
Trong tradng hgp ciia co di trong d day la cd Luon chiing toi chgn phuong phap kiem tra su tang tradng mat do than diing.
Sau hon 6 tuan di trdng, kiem tra 3 Id thi nghiem, mdi 16 co 10 bui, khoang 30%) sd lugng cae bui co bien bi mat do tac ddng co hgc ciia ddng chay hoac bi chet. Sd lugng cdn lai thich nghi va phat trien tdt, dieu nay the hien qua viec khao sat mat do tmng binh than diing d cac 16 thi nghiem, mat do tmng binh tang khoang 13%.
Hinh 2: Dung cu lay gidng cd Hinh 3: Van chuyen cd gidng den noi trdng
5. Quan ly va van hanh he sinh thai: Giai phap de nghi cho van de quan ly, bao ve va su dung cd hieu qua he sinh thai cd bien
Viec phuc hdi, phat trien va khai thac ngudn lgi trong cac tham cd bien la ddng luc chii yeu trong chien luge quan ly he sinh thai. Phat huy cac ky thuat phuc hoi va phat trien cac nguon lgi c6 gia tri kinh te trong tham cd bien nhu tdm, cua, ghe, ca. Khi dugc bao ve, ngudn gi6ng ca Mil, ca Dia, cua Bun vao cu tni trong cac tham cd bien. Cac hg gia dinh dugc giao nhiem -vu bao ve cac tham cd bien cd cuoc s6ng gan lien vdi ngudn lgi ma cac tham cd bien mang lai cho hg.
Trong tinh hinh hien nay, khi ngu6n lgi cac he sinh thai ven bd bi suy giam nghiem trgng, hieu luc ciia cac quy dinh ve quan ly va bao ve ngu6n lgi con chua cao, thi viec xay dung cac quy dinh, huong udc ciia dia phuong de bao ve va sit dung hgp ly tai nguyen cac tham cd bien can duge day manh. Hien nay chua cd cac th6ng ke day du ve suy giam da
dang sinh hgc va cac nguon lgi cd gia tri trong cac he sinh thai ven bd nhit la he sinh thai cd biln, nhung cd dilu rd rang ring mdt so loai cd gia tri trong cac tham cd biln ngay nay rit hilm gap hay khdng cdn niia nhu ca Ngua, dc nhay, Nhum sg, Hai sam cat.. .Nhilu loai tdm thudc hg Penaeidae, cua, ghe, ddng vat than mim, cac loai ca dac biet trong cac tham cd bien nhu ca Dia, ca D6i suy giam nhanh. Viec suy giam nay ngoai nguyen nhan do khai thac qua mite, con nguyen nhan chinh la do noi cu tni sinh vat bi xao trgn, cai noi uom nudi sinh vat bi pha hiiy.
Y nghia ciia viec phuc hdi cac tham cd bien la phuc h6i noi cu tni sinh vat, lam cho cac sinh vat sdng chung trong cac tham cd bien dugc da dang hon va cac ddi tugng nguon lgi cd gia tri da bi suy giam hay mat di nay dugc phuc hdi lai
Lgi ich kinh te cac tham cd bien gan lien vdi ddi sdng cdng ddng ngu dan ven bien tit bao ddi nay, la viing thudng xuyen xay ra cac hoat ddng nudi trdng va danh bat hai san.
Vi vay viec bao ve va quan ly nd phai xay dung tren co sd cdng ddng, dugc su ung hg ciia cdng d6ng vdi muc tieu sit dung cd hieu qua he sinh thai, duy tri, phat trien ben -viing ngudn lgi va cho mdi tradng sach.
Nghien ciiu mo hinh phuc hdi va bao ve noi cu tni cd bien ciing nhu ngu6n lgi sinh vat chung song giiip cho cdng dong hieu rd gia tri ciia he sinh thai cd bien ddi vdi nguon lgi sinh vat va mdi tradng, tit dd hg cd nhan thiic sau sac va img hd nd nhu la each duy nhat de bao dam sinh ke gia dinh. Vi -vimg phan bd cd bien chii yeu la vimg dudi trieu, cac tham cd bien it bi siic ep bdi viec phat trien nudi t6m hon rimg ngap man. Van de la nhan thiic cua cdng ddng mdt khi hg nhan thay ciing nhu dugc trang bi day dii cac hieu biet trong viec quan ly, phat trien sit dung he sinh thai mdt each hgp ly de dem lai hieu qua thiet thuc.
Vi vay, giai phap de nghi cho viec phuc hdi va quan ly he sinh thai dua tren co sd cdng ddng va vi lgi ich cua cong d6ng, do la:
- Giao cho cac hd gia dinh hoac ca nhan tien tien, quan ly khu -vuc trien khai md hinh phuc h6i, theo cac ky thuat da dugc chuyen giao, xae dinh ranh gidi khu -vuc bao ve.
Ngudi dan sit dung cac dien tich nay nhu dien tich canh tac va tuan thii theo dung luat phap Nha nudc.
- Ciing vdi viec di trdng phuc h6i va bao ve co bien, chuyen giao ky thuat cho ngudi dan nudi phuc h6i mgt so cac ddi tugng sdng chung trong cac tham co bien. Trade mat, d dia ban xa Tam Giang, dd la cac dii tugng hau, ngao, 6c nhay, dc cang, cua, ghe, ca mil.
Ngudi dan cd the dugc sit dung vimg dem phia ngoai tham cd bien de phat trien nghe
nudi.
- Khi ngudn lgi dugc phuc hdi, ngudi dan se dugc hudng dan each khai thac hgp ly de duy tri bin viing. Ngudi dan se cd 2 each thu nhap : thu nhap tu ngudn lgi tu nhien do phuc hdi HST va thu nhap tit viec phat triln nudi trdng mdt sd ddi tugng than thien vdi mdi trudng, thich hgp trong he sinh thai.
f l '
- Chinh quyen dia phuong can cd nhiing quy dinh va thdng bao rdng rai cho cac cdng ddng dan cu -viing Ian can ve khu -vuc phuc hdi bao ve, thuc hien nghiem luat phap Nha nudc cam cac hinh thiic danh bat cd tinh hiiy diet.
Viec thu nhap ngudn lgi hi khu vuc bao ,ve phai la ddng luc va lgi ich hap dan khien ngudi dan phai n6 lire gin giu va tdn tao he sinh thai. Neu biet khai thac hgp ly md hinh, sit dung triet de cac co sd khoa hgc, ngudi dan se khai thac -viing bao ve phuc hdi nhu noi canh tac ciia hg va md hinh chac chan se dugc nhan rdng nhieu dia phuong khac. Khi do tai nguyen ngudn lgi va tai nguyen mdi tradng ciia cac he sinh thai ven bd se dugc phat trien, sit dung mdt each hgp ly va ben -viing.
Thdi gian cdn qua ngan de cd the danh gia cu the su phuc hdi ciia ngudn lgi sinh vat trong he sinh thai, nhung cd dieu rd rang rang hang ngay c6 kha nhieu ghe thuyen cua ngu dan tap trang khai thac xung quanh hang rao khu vuc quan ly va nhdm hat nhan rat vat va trong viec bao ve. Ca Mil con, ca Dia, ca Ddi, tdm, cua, ghe la cac ngudn lgi cd gia tri tap tmng cu tni va an nap trong khu -vuc quan ly he sinh thai co bien.
IV. KET LUAN
- Thdn 1, 2 xa Tam Giang, huyen Niii Thanh cd dien tich 10 ha dugc chgn de trien khai trinh dien md hinh phuc hdi he sinh thai cd bien. Day la -viing dugc lua chgn dua theo cac tieu chi ve da dang sinh hgc, dugc xae dinh cd y nghia quan trgng ve ngudn lgi sinh vat cho "viing ven bien Nui Thanh va -viing bien lan can. Tham cd bien dang bi suy giam khoang 30%, nguyen nhan chinh do cac hoat dgng khai thac hai san cd tinh huy diet.
- Nh6m hat nhan thuc hien md hinh trinh dien gdm 4 ngudi, cd nhdm tradng, do chinh quyen dia phuong va cac doan the gidi thieu. Pho Chii tich UBND xa Tam Giang dugc phan cdng theo ddi, giam sat va ddn ddc hoat ddng ciia nhdm.
- Loai cd bien da dugc chgn de di trdng phuc hoi la cd Luon. Day la cac loai im the ban dia. Cac thit nghiem cho thay chiing cd kha nang di trdng va phat triln tdt, sau 6 tuin di trdng, mat do than diing cd the tang den 13%.
- Viec van hanh md hinh dugc de nghi tren co sd gin kit lgi ich khai thac hgp ly va ben vung ngudn lgi trong he sinh thai co biln vdi viec quan ly va bao ve chiing.
Ldi cam on: Tac gia chan thanh cam on T6ng cue Bao ve Mdi tradng, Bd Tai Nguyen & Mdi tradng da tai trg kinh phi va PGS TSKH Nguyin Tac An, chii du an da tao dieu kien cho viec thuc hien md hinh, ThS Nguyen Xuan Vy, phong Thuc vat biln, Vien Hai duong hgc, hd trg cdng tac khao sat va nhom hat nhan d xa Tam Giang, Nui Thanh gdm 4 ngudi do dng Dinh Vien lam nhdm tradng da td chiic quan ly va di trdng cd biln.
TAI LIEU THAM KHAO
1. Davis, R. C. and Federick T. Short, 1997. Restoring eelgrass Zostera marina L.
habitat using a new transplanting technique: the horizontal rhizomeMethod. Aquatic Botany 59: 1-15.
2. English, S.,Wilkinson, C. and V. Baker, 1994. Survey Manual for Tropical Marine Resources. Chapter 5: Seagrass Communities pp. 235-264.
3. Huynh Quang Nang va Nguyen Hiru Dai, 1981. Quy pham Nha nudc. Quy pham tam thdi dieu tra tdng hgp bien. Quy pham dieu tra rong bien. QPVN 17-79, tr. 1-43.
Uy Ban Khoa hgc va Ky Thuat Nha nudc Ha Ndi an hanh.
4. Nguyen Hiru Dai, Nguyen Xuan Hda, Pham Hiru Tri va Nguyen thi LTnh, 1999.
Cac tham cd bien phia Nam Viet Nam. Tuyen tap Bao cao Khoa hgc Hgi nghi toah Qudc lan thii 4 ve Khoa hgc va cdng nghe bien. Ha Ngi 12-13/11/1999. Tap 2 : 967- 974. NXB Thdng ke, Ha Ngi.
5. Nguyen Huu Dai, Nguyen Xuan Hoa, Pham Huu Tri and Nguyen Thi Linh, 2000. Seagrass beds along the southem coast of Vietnam and their significance for - associated flora and fauna. Collection of Marine Research Works. Vol. 10: 149-160.
Science and Technique Publishing House. Ho Chi Minh City.
6. Nguyen Hiru Dai, Pham Hiru Tri, Nguyin Thi LTnh, Nguyen Xuan Vy, 2004. Su suy giam cac tham co bien d Khanh Hda va kha nang phuc h6i chung. Tuyen tap bao cao Khoa hgc Hgi nghi Khoa hgc Biln Dong 2002. tr. 359-368. Nha Trang , 16-
19/9/2002. NXB N6ng Nghiep
7. Nguyen Hiru Dai, 2005. Phuc h l i va bao ve cac tham cd biln - Md hinh quan ly va phat trien ben -virng -viing bien ven bd. Ky yeu Hdi thao toan Qu6c Bao ve m6i tradng va Nguon lgi thiiy san. Hai Phdng 14-15/01/2005. Tr. 388-395. NXB Nong nghiep Ha Ngi.
8. Philips, R. C. and C. P. McRoy, 1990. Seagrass Research Methods. Monograph on Oceanographic Methodology. Unesco, Paris.210 pp.Unesco, Paris. 210 pp.
9. Saito, Y. and Atobe, S., 1970. Phytosociological study of intertidal marine algae. I.
Usujiri Benten-Jima, Hokkaido. Bulletin of the Faculty of Fisheries, Hokkaido University, 21:37-69.
10. Spurgeon, J., 1998. The Socio-Economic Cost and Benefits of Coastal Habitat Rehabilitation and Creation. Marine Pollution Bulletin 37(8-12): 373-382.
MANAGEMENT AND RESTORATION OF SEAGRASS BEDS IN NUI THANH DISTRICT, QUANG NAM PROVINCE
NGUYEN HUU DAI
Abstract: 10 hectares of seagrass beds in Nui Thanh district, Quang Nam province have been chosen and signed by People Committee of Quang Nam province. No 938/QD- ilBND in July 9/2008, and given tQ the Project "Integrated Management of Coastal Zone Quang Nam province "for management and restoration of seagrass ecosystem. This area is an important distribution area of seagrass in An Hoa lagoon, Nui Thanh district. Zostera japonica is dominant species, the cover can reach 25-50%. Unfortunately, these beds are
quickly reduced by several destructive flshing gear and methods. A model of management and restoration of seagrass beds has been carried out with the help of local government, four workers in seagrass group and local people. Zostera japonica had been transplanted by planting unit method. Preliminary result showed that after 6 weeks of planting, the density
increased 13%. A proposed solution for management seagrass beds is based on close connection between the benefit from the reasonable and sustainable exploitation of the resources in seagrass ecosystem and their management.
Ngdy nhan bdi: 16 - 7 - 2009
Nguoi nhan xet: PGS. TS. Nguyen Hiiu Phung
