I KHOA HOC — > ; . l g r « 1 5 M ! l : ^
NGHIEN c u t ; VA DE XUAT PHlTOfNG AN QUAN LY NlTdC CHO RlTNG TRAM Cf YU'CTN QUOC GIA U MINH THU*aNG
TRONG DIEU KIEN HIEN NAY
Pham Van Tung Viin Ky thudt bien Tdm tat: Tie sau khi xdy ra chdy rung ndm 2002 den nay, do Idm ly e nggi chdy rimg co the xdy ra nen qudn ly nu&c trong hd rieng ludn duac giit & miec cao nen dnh hu&ng l&i suphdl triin ciia cdy trdm. Mac dii tie ndm 2010 vuang qudc gia (VQG) U Minh Thuang (UMT) dd cd nhung diiu chinh phdn khu qudn ly nu&c trong rieng, buac ddu da mang Igi hiiu qud cho idm A vd khu B, nhung khu C la vung quan trpng nhdt cua rieng trdm U Minh thi chua duac cdi thien ddng ki. Nhu vdy, cdn phdi cd nhimg dieu chinh trong qudn ly nuac cho timg phdn khu cung nhu cho cd vimg long ho. Kit qud nghiin cuu dua tren hien trgng hi thong cong trinh hien cd, cdn cu mpt phdn vdo quy hogch VQG dd duac phe duy$t de dua ra quan diem dieu chinh Igi phdn khu qudn ly nu&c trong rieng trdm v&i 5 khu. Tdc gid de xudt khu D cd dia hinh cao v&i ldp than bun ddy duac bdo vi nghiem nggt di qudn ly mdi tru&ng vd tdng cu&ng fdid nang phdt triin cua cay tram. Tdng khd ndng phuc hoi ldi sinh rimg trdm & cdc khu cd dia hinh thdp han md vdn ddm bdo duy tri ddy dii cdc sinh cdnh dgc trung ciia rimg trdm phyc vu cho bdo tdn da dgng sinh hpc theo dgc trimg tu nhien von cd cua nd.
Tic khda: Phdn khu qudn ly nu&c. Qudn lynu&c. Vic&n Quoc gia U Minh Thuang.
Summary: Since the forest fire has occurred in 2002 so far, due lo the fear of forest fires can occur, so water management has been always kept at high water level Although from 2010 U Minh Thuong National Park has made adjustments of water management zoning in the forest, it has been initially effective in zone A and zone B. but zone C, the most important area of U Minh forest, is unimproved yet. Therefore, current zoning option needs to be adjusted for water
management. The study was based on the current stale of the existing system of structures, based partly on the approved national park planning lo provide a view for revising the water management subdivision in the Melaleuca forest with five zones. Zone D with high terrain and Ihickpeat layer has been highly proposed for water management. Increase the restoration ability of Melaleuca forest in the lower terrain areas while ensuring the proper preservation of typical Melaleuca forest habitats for biodiversity conservation according lo its natural characteristics.
Keywords: Water management zoning. Water management, U Minh Thuong National Park 1. M d ©AU bdi he thing cdng trinh tiidy Igi didu tilt nguIn ,.T I--- ' ' * • 1,1,' 1, *u- I, • 1,'t t«;l„ nude mua nhdm quan W vd duy tri muc nude Nghien cuu qua tnnh hinh thanh va phat tnen lit , , . , , ,
^ , *- .... X. , - . chong chay rimg de bao ve khu rung tram ddc cua rung ttam, dac biet sau dgt chay rung ^ , •; .x , TXT^O^V ^, X *- , , .1-' -, - -innt I. *i,- l l . - „+v,i K,^„ „a dung quy hiem cua DBSCL. Che do thuy van tiiang 3 nam 2002 cho thay khong the bao vg • ^ ^.,-' .^ , . •' , .!•. im^ TT n*- L -n- - 11." T ™ tAt duoc dieu tiet d cae thai diem ttong nam bang tdt VQG U Mmh Thugng neu khong lam tot ^ • _ « i, < ^- tr u - u- edng tdc qudn 1^ nude. cac cdng trinh edng, dap, ttgm bom ttdn hg
thing dd bao ttong, de bao ngodi nhdm muc dich VQG U Mmh Thugng Id khu vyc dugc khep kin ^^ y^ ^guon nude mua vao cudi miia mua vd dilu tilt chiing keo ddi sang hit miia khd. Cae Ngaynhgnbai: 13/3/2018 cdng trinh phyc vu cho vide qudn ly vd dilu tilt Ngay tiiong qua p h ^ b>fn: 20/4/2018 ^ y ^ . ^^^ ^ yQG dugc ddnh gia Id chua hodn Ngay duygt dang: 26/4/2018 -^ . a
TAP CHl KHOA HOC VA CPNG NGHE THCIY Lpl SC5 43 - 2018 85
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thien ndn khong cd sy phdi hgp boat dpng dieu tiet nude ddng bd, ddn den muc nude ludn d mdc cao trong rimg. Day Id mdt phan nguyen nhdn ldm cho VQG bi ngdp nude keo dai lam cho rung tram dac dyng phdt trien kem va gdy d nhidm ngudn nude ttong khu vyc rimg. [5] [6]
Nghidn cdu, lua chpn phuang dn phan khu quan ly nude cho rimg nham tim ra each thdc phdn khu hpp Iy, kdt hgp vdi he thdng cdc cdng ttinh cdng, ddp dugc bd sung, didu chinh giup cho vide qudn ly didu tidt nude d VQG thudn tidn nMm phyc hdi vd phdt trien he smh thai rdng trdm sau chay rdng la myc tidu can hudng din cua tde gid bai bdo ndy.
2. D ^ C DIEM TV* NHIEN VA THU*C TRANG PHAN KHU Q U A N LY N u ' d c 6 VQG U MEVH THU'gfNG
Vi tri d|a Iy
VQG U Mmh Thugng cd dign tich 21.107 ha
gdm vdng loi 8.003 ha, vung ddm 13.069 ha va mOt phdn dien tich de kgp giua vung ldi va vdng dem 35 ha, ttdn dia ban hai xd An Mmh Bde vd Mmh Thudn huygn U Mmh Thugng tmh Kien Giang, ndm vl phia Tay cda vung bdn ddo Cd Mau.
Hinh 1. Vi tri viing nghiin cuu VQG U Minh Thuang thupc DBSCL Dilu kien dia hinh
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a) Trudc chdy rung b) Sau chdy nmg Hinh 2. Phdn bd dp cao viing loi cua VQG tru&c vd sau chdy rimg [6]
Khu vyc U Minh Thugng c6 dia hinh thap va kha bdng phdng, bi chia cdt nhidu bdi hg thing kenh rach. VQG ndm d trung tam cua vung U Minh Thugng, chdnh lech dO cao gida eac khu
vyc <l,5m. Tdng qudt dia hinh vung ldi ctia VQG trudc va sau chdy rimg (Hinh 2), nhu sau:
- Trudc khi xdy ra vy chdy riing ndm 2002, phdn bo do cao cd dang gd hinh "mai riia", ddc td
86 TAP CHf KHOA HpC VA C O N G N G H C T H O Y L p l SP 43 - 2018
tixjng ra ngodi. Cao nhdt d trung tdm phia Nam vd thdp nhdt d cdc trang nude phia Bde, phan bd eao do tii 0,fr5-2,2m so vdi muc nude biln.
Chdy rimg dd lam gidm dd eao cua ldp than btin, lam thay ddi dia hinh. 0 nhidu noi ldp tham bun bi chdy hodn todn din ldp ddt set.
Phdn bd do cao dia hinh hien nay khdng dlu, khu vyc trung tdm ed dia hinh cao vd thdp xem ke nhau nhung rtiiin chung d phia Nam cao ban d phia Bde. Didn tich vdng I5i cua VQG ehu ylu d dO eao <1,0m chilm din ==48%, didn tt'ch cd do cao tten 1,6m ehi chilm «7%.
Thifc trang quan ly nude
Trudc nam 20p2, VQG U Minh Thugng khdng qudn I>' didu tiet chl dO nude nhu hidn nay ma dd cho rimg phat tridn thuan theo tu nhien. Ddu miia khd, cae dap tgm dugc dyng ldn de ngan nude mgn xam nhap. Kdt qua so dgc myc nude d trung tdm VQG (tgi vi tti sd 3) tiidp nhdt Id 87cm (tiiang 2-3), cao nhdt la 154em (tiidng 6) va tnmg bmh la 132cm (till hidn ttdn Hmh 3) [6].
I KHOAHO'C ^ R g ? H M ^ Td nam 2002-^2009, qudn ly nude Id mOt bac (mdt myc nude gidng nhau) mac du VQG dugc phan lam 3 khu (khu A, khu B vd khu C - Hmh 7), todn vung loi Id mOt khu ldn. Kit qud sd dpc myc nude d trung tam eua VQG thdp nhdt la 103cm (thdng 5), cao nhdt id 140cm (thangl2) vdtrungbmhld I17cm (Hmh4) [6].
Td nam 2010 ^ hien tai, qudn ly nude tiieo cac khu khac nhau: khu A, B vd C (Hinh 7). Sau khi phan chia cdc khu, kit qua thdng kd dien tich theo cao do d 3 khu duge ndu ttong Bang 2. Kit qud sd dgc myc nude cao nhat khu A va B Id 119cm, khu C la 151cm; myc nude thdp nhdt khu A vd B la 63cm, khu C Id 117cm (Hmh 5, Hinh 6). Sd lieu cao dO dia hinh cho thdy, khu A va khu B phan bo didn tich chu ylu d cao do dudi 1,2m, cdn khu C phan bd cao dO dia hinh chu ylu ttong khoang rdt rOng tu 0,8m din 2,2m.
Cao do dia hmh trung binh khu A Id 0,83 m, khu B Id 0,83m vd khu C la 1,22m. Nhu vdy, hai khu A va B CO cao dp dia hinh gdn tuang ty nhau vd tiiap hon khu C trung binh =^0,4cm.
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Hinh 4.Biiu do muc nu&c & vung loi VQG giai dogn lie ndm 2002 — 2009
Hinh 5. Muc nu&c & VQG khu A &B giai dogn tie 2010-2014
Hinh 6. Myc nu&c & VQG khu Cgiai dogn tie 2010-2014
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Hinh 7. Ba khu qudn ly nu&c tie ndm 2010- 2016 & VQG UMT Nhdn xet ve chl do quan ly nirdc:
Qudn ly chd dO nude trong VQG U Minh Thugng tu sau khi xdy ra chdy rimg thdng 3/2002 den nay cd nhidu thay ddi so vdi trudo khi xdy ra chdy rimg [6]:
Muc nude trung binh d mdc cao hon nhidu so vdi cao dp trung binh, the hidn qua cdc thdng sd so sdnh giiia Hnwa vd Z,b mat ddt rimg vung ldi VQG timg thdi ky:
+ Trudc khi xdy ra chdy rimg cd muc nude trung binh nam (//nain=132cm) gdn ngang bdng vdi cao dO trung binh (Ztb=133cm);
+ Giai doan td ndm 2003-2009 ed muc nude trung binh nam (7/nam=117em) cao hon so vdi cao dO trung binh (Ztb=105cm) la 12cm;
+ Giai doan td ndm 2010-2015, d Khu C cd
^nam=137cm cao ban so vdi cao dg trung binh Khu C (Z,bc=122cm) la 15cm.
Ty le cac dign tich ngap nude dai dign cho
cde sinh cdnh ttong mdi trudng sinh thdi ed su biln ddi ldn, till hidn ro nhat qua dign tich bi nggp nude quanh nam:
+ Trudc khi xdy ra chay rimg cd - 3 0 % diOn tich ngap nude quanh ndm, ==22% diOn tich khdng ngdp nude vd =48% didn tich ngap nude theo mtia;
+ Giai doan tu nam 2003-2009 cd =50% didn tich ngdp nude quanh nam, =21% didn tich khdng ngap nude vd =29% didn tich ngdp nude theo mua;
+ Giai dogn td nam 2010-2015, d Khu C co
=39% dien tich ngdp nude quanh nam, =17%
didn tich khdng ngdp nude va =44% dien tich ngap nude theo mua.
Thdi gian muc nude dudi eao dp trung binh la 6 thdng giai dogn trudc khi xay ra chdy rdng thi sau khi xdy ra chdy rimg hau nhu khdng co thdi gian myc nude dudi cao dO trung binh.
Phdn khu qudn ly nude tu nam 2010 ddn nay budc dau da phat huy hidu qud. Nhin lai sudt thdi gian ddi td ndm 2003-^2009 mgc du khu A vd B khdng hi chay trudc dd nhung bi ngap sdu hodn todn ttong nude, thi td ndm 2010 den nay dd duge phyc hdi tdi sinh trd Igi. Tuy nhien, mdc phyc hdi van ehua cao vi myc nude trung binh cdn rdt cao vd thai gian ngap edn ddi.
Dli vdi khu C, phdn khu dd qudn ly nude tu ndm 2010 din nay cd mpt s l bidn ehuyen tich cue nhung khdng nhilu, chua ro ret. Didn tich bi ngdp quanh ndm van ldn, thdi gian ngap nude trung binh van keo dai.
Bidn hdi v l h^ sinh thdi ru'ng tram Ket qua so sanh bidn thien dign tich cdc kidu thdm thyc vgt gida cdc ndm 2006 - 2009 - 2014 ben cgnh s l lieu do dgc vd che dO nude vd dua ra kit ludn: [3]
Chl dp muc nude dnh hudng manh den su thay ddi thdm thyc vgt, muc nude ngUp sau va trong thdi gian ddi tu nam 2006 din 2009 da
88 TAP CHf KHOA HOC VA C P N G N G H £ T H O Y Lpl SP 43 - 2018
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KHOA HOClam cho tiiyc vgt rdng ttdm gidm 498,36 ha, ddng cd ngap nude theo mtia gidm 1.417,04 ha, ddm ldy thuc vdt tiiuy sinh tang 1.885,4 ha.
Thay ddi phuang dn qudn Iy nude nam 2010 da lam cho thdm thuc vat d VQG phyc hdi, hinh thdnh 14 kiiu qudn xa thuc vdt dan xen tao nen nhilu kieu thdm thyc vat dgc trung cua hd sinh thdi rung tram ngdp nude theo mua.
Didn tich mat nude gidm" do bi xdm ldn bdi cdc loai thuc vdt thuy sinh vd thay the bdi ding cd ngdp nude theo mua.
Kidn nghi VQG U Minh Thugng quy hogch quan ly nude thanh 5 phan khu vdi cdc chd dO myc nude khdc nhau theo ti'nh todn cdn bdng nude dam bao myc tidu phdng chdy chua chdy rimg vd duy tri cac gid tri da dgng sinh hpc cua rimg trdm ttdn dat than bun.
Ve hg sinh thai rimg tram [2] [6], kit qua bidn hOi cdc nghien cdu dua ra nhgn xet: O mOt khia canh, chdy rimg da lam gia tdng sy sinh trudng vd da dgng sinh hoc cua cdc lodi dpng, thuc vat. He thuc vat tang td 243 loai ldn 250 loai; he dpng vdt, chim tang tii 172 lodi len 188 Ioai, thu tang td 24 lodi Idn 46 lodi. Nhung khdng the phti nhgn rdng dgt chay rimg thdng 3/2002 vda qua cd hdu qud rat nghidm trpng, dien tich than bun bi mdt di rat ldn ma phdi hdng ttam nam mdi cd duge, thdm thyc v£it khu vyc bi chdy, ddc bigt Id rimg trdm tu 15 din 45 nam tudi bi mdt di vd phai cd thdi gian ddi mdi tdi sinh trd Igi,...
3. PHAN KHU PHVC VU QUAN LY
N i r d c CHO R I T N G T R A M
Phan tich hien trgng va quy hogch phan khu a) Phdn tich Men tr^ngphdn khu Ro rdng vigc phan chia lam 3 khu cua VQG td ndm 2010 ddn nay Id chua ddp iing dugc ydu cdu. Day la mdt phdn nguyen nhan ldm cho vide qudn ly nude d VQG thdi gian gan ddy ludn d mdc cao va khd kidm sodt.
Ket qud phdn tich cho thdy phan khu C dugc phan vung Id chua phti hgp: (1) didn tich khu nay qud rOng, chidm den 66% didn tich todn VQG; (2) cao dp dia hinh trong khu C rdt khdng dlu, chenh lech ldn vdi noi cao nhdt ddn -i-2,2m cdn nai thdp nhdt Id -i-0,6m; (3) vi dign tich ldn va cao dp khdng ddng deu ndn kho b l tri hd thdng cdng ttinh Idm cho vide quan ly nude ludn d mdc cao.
Hai khu A vd B cd didn tich nhd ban vd gaij bang nhau, cd dang hinh thoi vd dugc bao quanh bang de bao. Cao dO dia hinh cdc khu ed mdc dO chdnh cao khdng Idn, chdnh lech ldn nhat dgt 0,6m. Vi tri dia ly vd cdc dieu kien dia hinh, dia mao khd thugn tign trong quan 1^
dieu tilt chd dp nude.
b) Phdn tich quy hogch phdn khu Theo nghien cihi cda Pham Trpng Thinh [5], quy hogch cua VQG U Minh Thugng den nam 2020 dugc phdn ldm 6 khu, cd vi tri nhu tten Hinh 8, thdng so didn tich trong Bdng 3.
(Nguon: NCS xdy dung bdn do tie tdi liiu cua VQG UMinh Thuang [5]) Hinh 8. Quy hogch cdc khu qudn ly nu&c &
VQG UMinh Thuang
TAP CH( KHOA HpC VA C P N G N G H E T H C I Y L O I S P 43 - 2018 89
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Bang I. Phan bo d i | n tt'ch theo cao dO vung loi d VQG theo quy ho^ch
STT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Lap cao d9(m) 0,6-0,8 0,8-0,9 0,9-1,0 1,0-1,1 1,1-1,2 1,2-1,3 1,3-1,4 1,4-1,5 1,5-1,6 1,6-1,7 1,7-1,8 1,8-1,9 1,9-2,0 2,0-2,1 2,1-2,2
>2,2 Tong
IChuA DT (ha) 880 164 148 64 gg 4 1 0 0 0 0 0 0 0 0 0 1.349
%
65 12 11 5 7 0 0 0 0 0 0 0 0 0 0 0 17
KhuB DT (ha) 826 224 160 55 48 38 23 0 0 0 0 0 0 0 0 0 1.374
%
60 16 12 4 3 3 2 0 0 0 0 0 0 0 0 0 17
KhuC DT (ha) 0 211 106 95 73 72 51 18 29 12 5 0 0 0 0 0 672
%
0 31 16 14 11 11 8 3 4 2 1 0 0 0 0 0
s
KhuD DT (ha) 4 130 145 123 134 Igg 203 199 201 130 190 127 147 85 70 17 2.093
%
0 6 7 6 6 9 10 10 10 6 9 6 7 4 3 1 26
KhuE DT (ha) 8 133 135 152 168 116 404 411 169 16 9 8 4 3 2 2 1.740
%
0 8 8 9 10 7 23 24 10 1 1 0 0 0 0 0 22
KhuF DT (ha) 0 189 198 76 170 86 45 11 0 0 0 0 0 0 0 0 775
%
0 24 26 10 22 11 6 1 0 0 0 0 0 0 0 0 10
TSngDT (ha) 1.718 1.025 1.077 638 753 450 694 655 448 167 122 89 79 38 33 17 8.003 (Ngudn: [6])
> Cdc khu A vd khu B
Khu A vd B (didn tich ldn lugt Id 1.349 ha vd 1.374 ha, gidng nhu each phan khu hien tai), trudc khi chdy rimg xdy ra cd sinh cdnh la rimg tram ngdp nude theo mua. Mac du rimg khdng bi chdy nhung td khi xdy ra chay rimg den nam 2009, do qudn ly nude d mdc eao trong khi dia hinh thap dd ldm suy thodi rimg.
Tu nam 2010 den nay duge dilu tidt che do nude ridng ndn rimg da tung budc phyc hdi va tdi sinh trd lai.
>KhuE
Khu E (dign tich la 1.740 ha) cd eao dO dia hinh trung binh Id 1,34m, cao nhdt Id 2,21m va thap nhdt la 0,68m (chenh cao tuyet dli la 1,53m). Ddy la khu vyc bi chdy rimg ndm
2002 ndn tao ra nhiing vung trung cyc bg d gida xen lan cae vimg eao. Mac du chenh cao tuyet ddi ldn nhung nhin chung thi kha ddng ddu vd cao dO d khoang 0,8-^1,6m.
Khu E nam giua khu D d trung tam cd cao do dia hinh trung binh cao nhat vd khu F d ria ngodi cd cao dO thdp hon. Dia mao dgng hinh binh hanh, gidp vdi kdnh trye trung tam. Khu E dugc danh gid thuan Igi ttong quan ly, dieu tiet chd do nude.
Qudn Iy nude trong khu E s§ tao ra ddy du cdc sinh cdnh dgc trung cda hd sinh thdi rimg trdm, cdc sinh cdnh xen ke nhau do dia hinh thay doi, tao cam gidc rdt da dang, thu htit.
Ddnh gid: Khu E cd chdnh lech cao dO ldn, the hien nii bat cdc sirtii cdnh dae trung cua he siitii thdi rimg ttdm vdi cac vdng cd didn tich
90 TAP CHf KHOA HOC VA CpNG NGH? T H O Y Lpl SP 43 - 2018
khdng ngap, didn tich nggp tiieo mtia vd dign tich nggp quanh ndm, ed gid tri bdo t i n cao.
Khu E ndm giua khu D cao nhdt VQG vd khu F thdp ban nen dugc ddnh gid Id thudn lpi ttong edng tdc qudn Iy, dilu tilt chl dp nude.
>KhuF
Khu F (didn tich Id 775 ha) cd cao dg dfa hinh TB Id 1,0m vd thudc vdng thdp trong VQG, cao do dia hinh nhdt cao la 1,41m vd thap nhdt la 0,81m (chenh cao tuygt ddi la 0,6m). Khdng nen duy tri muc nude cao d khu ndy de phyc vy chong chdy rimg vi hieu qua thdp, hien ttang rimg ttdm bi suy thoai vi tich nude d mdc cao lau ngay. Khu F can dugc phyc hoi vd tgo ra cdc sinh cdnh da dang ban.
Khu F ciing vdi khu E tao ndn sy da dgng vd sinh cdnh xen ke nhau va Idm rOng them ve khdng gian.
Bdnh gid: Khong can phan lai khu F nhung thay ddi quan didm qudn ly, didu tidt chd dg nude dd dap dng tdt ban eho sy bao ton vd da dgng sinh hgc.
>KhuCvdkhuD
Khu C vd khu D (dign tich ldn lugt Id 672ha vd 2.093ha) theo quy hoach cd mgt sd bat egp, cdn phan chia Igi cho phu hgp hon.
Ndn thu nhd khu D vao vung trung tdm, bao ttgn vimg bdo vd nghidm ngdt. Day la noi cd dia hinh cao nhdt, cdy ttdm tdi sinh phdt trien tit nhdt cua VQG, Id noi tap trung ldp than bim day cdn sdt Igi sau chdy rung de t h u ^ tiln trong qudn ly. Khi dd khu D cd cao dp dia hinh ddng ddu hon vd dugc ddnh gid Id:
+ De dang dilu tiet ehd dO nude dam bao cho sy tin tai cua than bun;
-I- De ddng didu tilt chl dO nude ddm bao phdng chlng chdy rimg;
-f- De dang dilu tiet chd dO nude ddm bdo duy tri cde sinh cdnh ddc trung ciia rimg ttdm.
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Ndn md rgng khu C theo quy hogch va chuyin ddi ehdc nang td khu tru nude phdng chdy rimg sang khu phuc hoi vd tdi sinh. Sau khi chuyin dli ehdc ndng vd md rgng dign tich phd hgp, khu C se duge ddnh gid Id:
+ Thudn tiOn ttong QL nude khi nam canh khu D vd thap dan ra phia ngoai;
+ Cling gidng khu E, qudn Ij? nude trong khu C se tgo ra day du cdc sinh canh dgc tnmg cua he sinh thdi riing tram, xen ke nhau tao cam giac rat da dgng vd sinh cdnh.
c) Ddnh gid chung
Trong giai dogn td sau khi xay ra chdy rimg den nay, VQG da cd nhung thay dli v l phan khu, thay ddi vd qudn ly vd didu tilt che dO nude nhimg ddu ehua mang lai hidu qud [6], Vi vdy, cdn ed su dilu chinh lai phan khu.
Gid nguydn mgt bdng hien ttang vdi cdc co sd ha tdng Id hg thing edng ttinh hidn cd ludn Id uu tidn, vi moi thay ddi ttong vide xdy dung d cdc VQG deu phdi ed mgt Ig trinh, kd hogch vd duge sy chap thuan eua ca quan cd thdm quydn. Tuy nhidn, theo [5], [6] thi VQG cd hg thdng cdng trinh chua ddp dng duge yeu cdu, khdng tidu thodt kip nude khi cdn tidu, khdng bd sung kip nude khi cd nguy co chdy rimg,....
Phdn lai khu qudn Iy rimg vd bd sung cdng ttinh hg tdng Id vide lam cdn thidt ttong gian doan tdi d VQG. Nhidm vy nhdm khdc phuc nhung hgn chd ma he thong co sd ha tdng hidn nay ehua ddp dng dugc ydu cdu quan ly nude theo eac tidu chi ddt ra Id ddp dng cho sinh trudng ctia cay tram, ydu cdu bdo tdn da dang sinh hgc vd phdng chdng chdy rimg.
Lua chgn phu'ong an phan khu
Nghidn cdu sinh dua ra 2 phuang an phan khu C vd D khde nhau so vdi quy hoach nhu da lap luan de lya chpn phuong an phu hgp hon, thi hign tren Hinh 9 va Hinh 10.
TAP CHf KHOA HpC VA CPNG NGH? T H O Y L p l Sp 43 - 2018 91
I KHOA HOC'"^MS33!BI^B
Hinh 9. Phdn khu phuang dn 1 Hinh 10. Phdn khu phuang dn 2 Nhan xet vd so sanh uu, nhuge didm cda 2 phuong dn phdn khu vdi nhau vd khde phuc nhihig hgn chl ttong quy hoach dugc ndu trong Bdng 4.
Bang 2. So sanh cdc phirong dn phdn chia khu vdi nhau va vdi quy hoach PHirONG AN 1
Dien tich cdc khu A, B, C, D, E vd F lan lugt la: 1.349ha; I.374ha; 1.773ha; 992ha;
1.740ha;vd775ha. (Bang 3.9)
Khu D duge phdn tdch rieng bigt, bao trpn phdn khu bdo vd nghiem ngdt dl thuan tidn ttong qudn ly.
Phdn lai khu C vd D dd bdo ve viing tdi nguydn tiian bim mOt each higu qud nhdt bdng each qudn ly nude theo cao dO- Tach ridng vung tiian bun rdt ddy (khu D); ddy, tiling binh vd mdng (khu C) de thugn tidn qudn ly^ phdng chlng chdy riing va bdo tdn than bim.
Dign tich khu D thu nhd lai vda phai (khdng qud nhd), ttong khi dia hinh cao vd d trung tam nen de dang kidm sodt chd dO nude, ndu dung dgng lye cap nude cung nhanh vd kip thdi hon.
FHirONG AN 2
Didn tich cae khu A, B, C, D, E va F ldn lugt la:
1.349ha; 1.374ha; 1.134ha; 1.631ha; 1.740ha;
vd 775ha.
Khu D cung dugc phdn tdch rieng bigt, bao rgng ban phdn khu bdo vd nghiem ng^t. Qudn ly khu nay phde tap han PAL
Giong phuang an I, nhung bdo vg viing than bdn ddy khd khdn ban do su khdc biOt vd cao do ttong phan khu D ldn hon.
Didn tich khu D cung dugc thu nhd lai vua phdi nhung ldn ban khodng 1,5 ldn didn tich trong PAL DiOn tich rOng ban ndn ehdc chan kidm sodt c h l dO nude phdng chdy rdng khd khdn hon, trong khi day Id vting cdn bdo ve nghiem ngdt.
92 TAP CHf KHOA HOC VA CONG NGHE THCIY LPI S(5 43 - 2018
^ J . I . U r l . l M ! ! ^ PHU'CflVG AN 1
Dia mao khu C vd D thugn hon quy hogch nhung phai ddo thdm mOt dogn kdnh dl phdn tdch. Day Id diem hgn chd so vdi quy hogch vl theo quy dinh cda Nha nude, ban chd tde dgng cda con ngudi vao nhdng VQG.
Phdi ddo thdm mOt doan kenh trong VQG ttong khi PA quy hogch thi khong can.
Didn tich khu C khd Idn nhung lien tuc. O dia hinh thdp han khu D ndn dd kidm soat chd dp nude.
Khu C khdng edn Id hd chda nude md chuyen thdnh khu phuc hdi sinh thai. Cd su da dang ttong cdc sinh cdnh ddc tnmg cda VQG xen ldn nhau.
Cach phan chia nay se cd kem theo gidi phap cdng trinh thuy Igi dieu tiet che do nude gida cdc khu, vd theo chu quan se thugn tien hon.
PHirCfNG AN 2
Gan gidng P A l , dia mao khu C va D thugn hon quy hogch nhung phdi ddo thdm mgt dogn kdnh de phan tdch. Vd cung cd nhung hgn che tuong ty.
Cung phdi ddo thdm mOt dogn kdnh ttong VQG ttong khi PA quy hoach thi khdng cdn.
Didn tich khu C vda phai hon PAl. Vd cung d dia hinh thdp ban khu D ndn de kiem sodt chl do nude.
Khu C ciing khong cdn la hd chda nude ma chuyen thdnh khu phyc h i i sinh thdi. Ciing cd sy da dang ttong cdc sinh cdnh dac tnmg.
Cach phan chia nay ciing cd giai phdp cdng trinh thuy Igi didu tiet chd dO nude, theo chu quan cua Nghien cdu sinh khdng thugn Igi bang PAl.
Lua chpn phuang dn: Td bdng nhdn xet vd so sdnh ttdn, thay rang ca 2 phuang dn ddu dd cdi thidn dugc mgt sd han che ma quy hogch gap phdi. Ndu so sdnh 2 phuang an thi phuong dn 1 c6 nhidu uu diem hon, phu hgp ban vdi didu kign hidn tgi. Chpn PAl dd tinh todn ehi tilt mOt sd cdc thdng s l ky thugt dac trung phyc vy cho qudn ly, dilu tilt che dO nude hgp ly nhdm phdt ttien rimg tram tdi sinh ndi rieng va rdng trdm ndi ehung d VQG U Mirtii Thugng.
^ Biln all phSn b& dif n lich theo cao d$ cic tllu khu
Hinh II. Biiu do phdn bd diin tich theo cao dp cdc khu
Bieu dd phan bd didn tich theo cao do cdc khu vung ldi d VQG U Minh Thugng theo PA
chgn dugc the hign ttdn Hinh 11. Qua dd nhgn thdy Khu A va Khu B cd dia hinh phd bien thdp nhdt VQG, ehd ylu Id dudi -i-l,0 m va tuong dng vdi 88%; Dia hinh cao nhat la Khu D rdi thap ddn sang 2 bdn la Khu C vd Khu E.
4. KET LUAN
Bai bdo da tdng hgp, phdn tich ddc diem tu nhidn, ngudn nude vd thuc trgng qudn l^
nude d VQG U Minh Thugng tu sau khi xdy ra chdy rdng (2002) eho den nay. Ket qud nghien curu da ddnh gid dugc nhdng dnh hudng cua vide qudn Iy nude ngap d mdc cao trong thdi gian keo ddi den sinh thdi rimg, tu dd dan den can phdi didu chinh lai phuang dn qudn 1^ nude thdng quan vigc bd tri lai phdn khu qudn ly nude trong rimg.
Dya trdn cdc dilu kign dia hinh, t h i nhuang vd d^c didm sinh thai cda cay tram tde gia da d l xudt dilu chinh Igi quy hoach phan khu quan ly nude ttong rimg tram vdi 5 khu. Khu D cd dia hinh cao vdi ldp than bun day dugc dd xuat che dO quan ly nude nghidm ngdt
TAP CHf KHOA HpC VA C O N G N G H E T H O Y LOl SP 43 - 2018 93
I KHOA HOC ^ . I . I J I t l J M ! ! : ^
nhdm cdi thidn khd ndng sinh trudng cua thi b l ttg eho nhau bdng cde cdng trinh thuy rung ttdm ddc dung, bdo vg da dang sinh thdi Igi ddp iing dugc ydu cdu sinh trudng cua cdy rung vd sinh vat dudi tdn rimg. trdm. Ngodi ni, d cdc khu cd dia hinh thdp hon Phan khu quan \-j nude theo t4c gia d^ xudt '='* * ^ ^^ ^"^i ' ^ " ^ ^ ' ' ° * ^ " " f • • * * dap tag ducrc yeu c k ch6ng ehay rimg, tSng ' " ^ " ^ " S ' ^ »"*= " « " •"* ""^ ^ ^ ^^ ^"^
, . , , . ,, ^ i . - ,!_. ... tn day dti cdc sinh cdnh ddc trung eua rung euomg kha ndng phdt tnen cua cay tram theo ' , ' , ^ ^ ^ • , ,
I.- 11. *i. ' -J- *-" XT *• ttdm phyc vu cho bdo ton da dang sinh hgc tung phan khu theo muc dg uu tien. Ngodi ra, , ±- »~ . . o iLi X i-i t-i* i -~ .t 1,- 11. ' theo ddc tnmg tu nhien vdn ed cua no.
khd ndng didu ttet nude giua cdc phdn khu eo . a . TAI LIIg;U THAM KHAO
[ 1 ] T6 ehdc CARE Qudc t l tai Viet nam (2002), Du dn phdt triin cpng ddng vd bdo tdn thien nhien Vu&n qudc gia U Minh Thupng.
[2] Luang Van Thanh, Phgm Vdn Tung (2011), Bien hdi, ddnh gid tong quan sinh thdi VQG U Minh Thuang vd di xudt gidi phdp bdo tin. Be tdi Khoa hgc cdng nghO, Sd Khoa hgc vd Cdng nghg tinh Kidn Giang.
[3] Trdn Van Thdng (2016), Anh hu&ng cua chi dp ngdp nu&c din thdm thyc vgt & VQG U Minh Thuang, Tap chi Ndng nghigp vd Phdt tridn Ndng thdn, thang 3/2016.
[4] Phgm Trgng Thinh (2002), Nghiin cieu diin biin tdi sinh t{e nhiin rimg trdm vd de xudt cdc phuang thuc phyc hdi rieng sau trdn chdy rimg thdng 3 ndm 2002 tgi VQG U Minh Thupng tinh Kiin Giang, Phan Vign Didu Tra Quy hogch Rdng Nam bd, Tp. Hd Chi Minh.
[5] Phgm Trpng Thinh (2015), Quy hogch bdo tin vd phdt triin ben vting VQG U Mirih Thupng, tinh Kien Giang din ndm 2020, Phdn Vign Dieu Tra Quy Hoach Rimg Nam Bg, Tp. Hd Chi Minh.
[6] Phgm Van Timg, Luang van Thanh (2016), Qudn ly nu&c & Vu&n Qudc gia V Minh Thupng tie sau khi xdy ra chdy rimg thdng 3/2002 din nay vd nhirng tdc dpng din h4 sinh thdi rimg, Tuydn tap Khoa hgc cdng nghg ViOn Khoa hgc Thuy lpi miln Nam ndm 2016.
94 TAP CHt mOA H p c VA CPNG NGHf T H O Y Lpl SP 43 - 2018
