H6i Dia ly Viet Nam D§i hgc Thii Nguygn DANH GIA DIEU KIEN KHI H^U PHUC VU PHAT TRIEN RlTNG NGAP MAN DAI VEN BIEN QUANG N I N H - H A T I N H
Tran Thj Thiiy Van, Hoing Luu TTiu Tliuy, Tdng Phiic Tuan Abstract
Mangroves occupy a modest area in the coastal provinces from Quang Ninh to Ha Tmh. they however have important signficances in terms of ecology as well as of protecting man-made values. Mangrove reforestation and afforestation, the necessaries for sustainable development in these areas, require many conditions including climatic ones. An assessment of climatic advantages and disadvantages for mangrove development in Quang Ninh - Ha Tinh coastal zone is herein presented on the following bases: current situation of mangroves, analyses of climate data from local meteorological stations, analyses of bioclmatic conditions and ecological thresholds. As a result of this, entire coastal zone from Quang Ninh to Ha Tinh has an ombrolhermic regime, in which basically mangroves can develop, however only two places, the North Quang Ninh and Ha Tmh, have optimal rainy and humid conditions for mangrove. Common adverse impacts of climate on mangrove are large annual temperature range, destruction of tropical depression or storm.
Entire zone can be bioclimalically divided into three following areas with the disadvantages for mangroves:
Quang Ninh - Hai Phong with cold weather conditions and frost; Thai Binh - Nmh Bmh with arid, cold, hot conditions but in moderate graveness: Thanh Hoa - Ha Tinh with hot weather and also arid condition added to Its northern part, Thanh Hoa - Nghe An.
1. MO DAU
Rirng ngap man (RNM) la mpt loai rimg die biSt cd cic loai cay gd v i cay bui thich nghi vdi mdi trudng nude man, phat trien d viing cua sdng ven bien nhipt ddi va can nhiet ddi. RNM la mpt he sinh thai hit siic quan trpng, vira cung cap nhu cau vl nhien lieu, thiic an... cho cpng dong dan cu ven bien, viia Ii biic tudng xanh viing chac chong gid bao, sdng than, sgt Id, lira sgch moi trudng ven bien, ban chi xam nhap man, bio ve nude ngim, tich luy cacbon, giam khi C02, duy tri da dang sinh hpc khi cd tiiien tai... RNM ven bien ndi chung va vimg Quing Ninh - Ha tinh noi rieng ngay cang khing djnh vai trd quan trpng trong chiin lupc phit trien ben vung cua lanh tho, dae biet trong boi cinh biln doi khi hiu va myc nude bien dang hien nay.
Khu vue ven bien tir Quang Ninh den Ha TTnh la noi t ^ tnmg cie trung tam kinh te, chlnh trj, xa hpi v i cd toe dp phat trien thupc loai trung binh kha ciia nude ta. Ben cgnh dd, con ngudi voi nhiing gii tri tgo dyng eua minh dang ngiy cing phii doi mgt nhieu hon vdi nhiing nguy ca nii ro ciia ty nhien ma RNM ven biln dupe xem nhu mdt giii p h ^ phi cdng trinh cd loi ich Idn trong bio vp quy dat, can bing sinh thai v i tao tai nguyen cho phat trien mpt so loai hinh kinh t l cd uu till v^
mgt kinh t l sinh thai nhu tham quan, du Ijch, bio ton v i phat trien cac gii tri sinh hgc.
Sy phit trien cua RNM, ben cgnh nhung co che, chinh sich cua chinh quyin, y thiic cua ngudi dan tiii cung rit cin nhiing nhan thiic ve bien sinh tiiai phat trien cua chiing. Vi vay, bai bio niy trinh bay rapt khia cgnh moi trudng smh thai phyc vu phat triln RNM ven bien - dd la cac d^
tiui vl khi hau dai ven bien tir Quing Ninh den Ha Tmh.
2. CO Sd D C L I E U V A PHUONG P H A P NGHIEN ClTU
Dl dinh gii dieu kien khi hgu den vipc phuc hoi v i phat riiln RNM ciia Viing nghifin cihi, sA lieu, dp dii chuoi tii nam I960 va duac cgp nhat den nam 2012, ciia 14 tram khi tupng ven bien tii
Kyyeu Hpi nghi Khoa hgcDia lp todn qudc ldn thit7
Hgi Dia \p Viet Nam Dgi hgc Thai NguySn Quing Ninh dSn H a TTnh d u a c sir dung (bang 1) v a b o sung t h e m b i n g cac ket q u a khao sat t h u c te ma cac tac gia da thuc hien trong mot so de tai, de an 6 khu v u c Quang Ninh - Ha TTnh.
Bang 1 • Cac trgm khi tucmg ddi ven biin tit Quang Ninh den Ha TTnh
J T j
1 2 3 4 5 6 7
Tfintram Mong Cii Tien Yen Caa Ong BmChay Hon Dau Phil Lien Thai Binh
K i n h d S 107°58' 107°24' 107°21' 107°04' 106°48' 106°38' 106°21'
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23°31' 21°20'
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20°27' 20"40' 20°48' 20°27'
T T 8 9 10 11 12 13 14
Ten tram VanLy Thanh Hoa
Tinh Gia Quynh Luu
Vinh Ha Tinh K y A n h
Kinh dp 106°18' 105°46' 105°47' 105°38' 105°40' I05°54' 106°17'
V i d e 20°07' 19°49' 19°32' 19°38' 18°40' 18°2r 18°05' Cie yeu to khi hgu dupc phan tich bao gdm: nang, nhiet dp khdng khi, mua, am va mot so hi^n tupng thdi tiet die biet.
Tren co sd cic so lipu da thu th^^i dupc, mpt so phuang pb;^ dupc su dyng de phin tich, danh gii dgc diem khi hau khu vyc nhim muc dich bio ve v i phit trien RNM. Cic phuong phap dupc sii dung gdm:
Phuong phip thong ke: chuoi so lieu nhieu nam dupc thong ke va tinh gia tri trung binh, mang tinh on djnh, phin anh dieu kien khi hgu ciia khu vyc.
Phuong phap so sanh: dgc tnmg khi hau dupe so sanh vdi bien thich nghi siiih thai ciia cay RNM, tao CO sd phan dinh eac khu vyc cd miic dp thich hop khac nhau
Phuang p h ^ khio sit thuc ^ a : thu t h ^ djnh tinh dan lieu ve RNM phat triln tren cae dgng dia hinh khac nhau vi dpng lue Iam bien doi ehiing.
Phuang p h ^ chuyen gia: dupe sir dung phye vy phan khu sinh thai, cd tinh chat djnh hudng phin tich khi hau phuc vy phit trien RNM.
3. HIEN TRANG RUMG NGAP MAN KHU Vl/C Q U A N G NINH - H A TTNH Tuy chiem dien tich khdng Idn song RNM trong khu vuc nghien ciiu Igi cd vai trd dgc biet trong chuoi thiic an, trong phdng hd dit lien v i dpng thdi cQng la noi cd tinh nhgy cim sinh thai cao. Cic loai thyc vgt than go ngap man thudng ggp gom: Mim bien Avicennia marina (Forsk.) Vierii., Ban chua (ban s^) Sonneratia caseolaris (L.) Engl, Dude vdi (Dang) Rhizophora stylosa GrifF., Trang Kandelia candel (L.) Druce, Vpt Dii (Vpt bdng dd) Bmguiera gymnorrohiza (L) Uunk., Sii Aegiceras comiculatum (L.) Blanco., Gii Excoecaria agallaocha L.,. Mpt cieh khii quit cd the thay ring su phan bo v i dae tinh cua RNM cd sy phan hda nhat djnh giiia cac khu vyc ^ a Iy trong Vimg v i chiing tdi cd cimg quan 4em vdi Phan Nguyen Hong [0] vdi 3 khu vyc cu thi sau:
+ Khu vue Quang Ninh, Hii Phdng (KVI): dia hinh doi niii va dao ddng vai trd chu dao va vi the RNM phit triln tren nen dit da it dupc cung cap chit dinh duong tir h? thong sdng ngdi ndi Inc. Quin xa cay ngap mgn cd smh khoi thap (chiiu cao trung binh 0,6-0,7m, ddi khi (fet tdi 1,6- 2m), thudng cd di?n phan bo nhd, hep, khong lien tyc d dpc ven bd tir Mdng Cii den Tien Yen
—4Quing,Ninh)^Thuy_Nguyen_(Hai,HiQngXyi tren mpt so cac dio nhu Cat Ba, Quan Lan .. Cic quan xi thudng gjq) d khu vyc nay la: Mam bien Avicennia marina, Sii Aegiceras comiculatum
™pc tren bai mdi boi; Dude vdi Rhizophora stylosa, Trang Kandelia oborata, Vpt du Biuguiera Synmonohiza rape tren cac bai n g ^ trieu trung binh; Vpt du Bmguiera gymnprrohiza mpc tren eie
^ trieu cao chiem uu till; Gii Excoecaria agallaocha, Cdc ving Lurruiitzera raeemosa, Coi Scyphyphpra hydrophyllace, Chp Myoporum bontioides mpc npi chi n g ^ triiu thgt cap; cic loii W9C tren cic bd dim it khi ng^p triiu Su Xylocarpus abovatus, Cui bien Herotiera littorallis, Tra Hibiscus tiUaceus,... ngoii ra cdn cd mpt so loii cay nude Ip nhu 6 rd gai Acanthus ilicifolius, Cdi Cypenis malaceensis ..
Kpyiu Hpi nghi Khoa hgc Dia lp todn qudc ldn tha 7
H6i Dia Iy Viet Nam Q^i hoc Thai Nguyen + Khu vuc Thai Binh - Ninh Binh (KV2): dja hinh dong bing, cira sdng mang tinh thong tri RNM chii yiu do trdng nhung cung cd khu vuc dupc khoanh vung bao ton ty nhien nhu khu RAMSAR Xuin TTuiy (Nam Dinh). Dae diem thuc vgt n g ^ man d day la phit triln tren nen day bim, biin set, bim cat, dupe cung cap dinh dudng khi ddi dao tir cic sdng nhung dd man chi d miic trung binh - t h ^ v i bien doi mgnh theo miia. Cic quin xa cay nggp man phd bien rpng hon cac loai ua nude Ip nhu Ban chua Sonneratia caseolaris d vung cira sdng, Sii Aegiceras comiculatum, 6 rd Acanthus ilicifolius, Trang Kandelia oborata. . Them vio dd, su md rdng lanh tho theo hudng lan bien ciing la ddng luc mgnh Iam thay doi cau tnic va dien the phit tnen cic loii theo thdi gian, Ngoai ra, trong 2-3 thap men trd Igi day, sy phit trien mgnh me ciia nudi trong thiiy san cung la mpt nhan to tic dpng manh me den su bien doi dien phu va thanh phan loai cua RNM nai day;
+ Khu vuc Thanh Hda - H i TTnh (KV3): dja hinh dong bang hep xen kpp giua cac nhanh niii, khoi mii an sit ra bien l i net noi bgt ciia khu vyc nay. RNM phit trien trSn nen day cat, cat biin vi bim set nhung hien trgng phan bo ciia chiing chi Ii nhiing minh nhd, rdi rac va bj tac dpng manh bdi boat dpng nudi trdng thiiy sin man - lp, Quan sit thuc te cho thay phia tiong cic ciia sdng Idn (sdng Ma, sdng Lam, sdng Kinh, sdng Nghen) cd mpt so loai ua nude Ip (Ban chua Sonneratia caseolaris, 0 rd Acanthus ilicifolius, Sii Aegiceras comiculatum, Cdi Cyperus malaccensis) va phia ben ngoii, tren nin dat nggp trieu cao cd Rang Acrostichum aureum, Gia Excoecaria agallaocha.
Dong thdi, d cac khu vuc it chiu inh hudng cua nude sdng cdn quan sat thay cic loii chju mgn cao nhu : Dude vdi Rhizophora stylosa, V?t dii Bmguiera gymnorrohiza. Mam bien Avicennia marina, Trang Kandelia candel
4. DAC TRUNG KHi HAU KHU Vl/C VEN BIEN Q U A N G NINH - H A TINH Viing nghien ciiu cd khi hau nhiet ddi gid mua, cd mua ddng Ignh do anh hudng cua ftont cue ddi khien cho bien dp nhipt nam dat tdi 12 - I3°C. Vdi vj tri ven biln nen khi hiu khu vuc nghien cim cd tinh dieu hda ciia hai duang, nhung do trai dii den xip xi 600kra dpc theo kmh tuyen ciing vdi inh hudng ciia dja hinh nen khi hiu cd su phan hda nhat djnh va vdi cac yeu to dia ly cd till phin djnh vdi 3 khu vuc: khu vuc doi mii ven biln Ddng bic Quing Ninh - Hai Phong (KVI); khu vyc dong bing ven biln Bic bd tir Thai Binh den Ninh Binh (KV2) v i khu vuc niii tiiip, doi xen dong bing hep ven bien Bic Trung bp tir Tiianh Hda den Ha TTnh (KV3).
Khu vuc I
Khu vuc I chju anh hudng sdm va manh nhat cua gid mua cue ddi, khien chp miia ddng laii nhat v i cung Ii khu vuc duy nhat cd kha nang xuat hien suong muoi so vdi toan viing. Nim d vl dp cao, nhiet d^ riung binh nam ciia khu vyc dao dpng trong khoang 22,5 - 23,2°C, thip ban so vdi cac khu vyc khic trong vimg nghien ciiu. Nhiet dp trung binh cic thing trpng nam dap dpng ti-ong khpang tii 15-29°C, cao nhat vio tiiang VII, thap nhat vio thing I (Hinh 1). Tong so gid ning dgt khoing 1392-1627 gid/nam ; tii thing V den tiiang XI cd nhieu ning nhat song so gid ning trong tiiang cung khdng vupt qui 200 gid/tiiang; cac tiling tii I den tiling IV la tiidi ky it ning vdi tiidi lupng nang hing thing dudi 90 gid. Anh hudng chin gid cua day Ddng Trieu lim cho khu vyc co m$t che dp mua am phong phii. Lupng mua cie tram trpng khu vyc dat tii 1530-2648 mm/nam. 0 Mong Cai, Tien Yen tiiudc phan phia Bic khu vyc, do nim ben sudn ddn gid ciia Nam Chau Linh - Yen Tii doi vdi luong gid miia mua hg va ben canh dd cdn thu dupc Iupng mua Idn trong eac dgng nhieu dpng khi quyen (bao, ranh tiiap, dudng dirt...) cd lupng mua nam cao va tid tiianh mpt trong nhung ttung tam^mua Idn-cdarViet Nam. Day cung Ii noi cd lupng mua cyc dgi roi vao tiiang VD trong khi cac phin cdn lgi cd cue dai mua roi vio tiling VIII. Thing XII, I v i II la nhirng tiiang rat it mua, Iupng mua tiiudng dudi 50 mm/tiiing. Toe dp gid tnm§ binh nam dao dpng trpng mpt khoing khac rpng tii 1,6 m/s d nhung khu vyc vinh kin cd die chin den 4,3 m/s d noi khdng dupc che chan. Toe dp gid cue dai cd till dat tdi 45 - 50ra/s v i tiiudng roi vio khoing tiling VII- IX.
Kpyiu Hdi nghi Khoa hgc Dia lp todn qudc ldn IhaT
H§i Dia ly Viet Nam Dai hgc Thai Nguyen
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Hinh 1. Mdt s6 ddc tnmg khi hgu do tgi cdc trgm & khu vuc 1 Trai tren - Nhipt dp trang binh thing; Phii tren - So gid ning tnmg binh thing Trai dudi - Lupng raua trung bmh thing; Phii dudi - Toe do gid cue dai cac thing Khu vyc 2
Mua ddng d khu vyc nay tuy Ignh ban so vdi KV3 nhung van im ban so vdi KVI. Nhipt dp trang binh nam khoang 23,5°C, nhiet dp trung binh thing dao dpng trong khoing I6-29''C vdi cue tieu li thing I v i eye dgi vao thing VH (Hinh 2). Tong so gid ning dgt I580-I660 gid/nam; ning nhilu trong flidi gian tir thing V din thing X vdi thdi Iupng tren 160 gid/thang, cao nhit l i thing V va thing VII; thing it ning nhat Ii tiling II va IH vdi thdi Iupng dudi 50 gid/thing. Luang mua trong khu vyc dgt 1677-1712 mra/nam. Bien trinh mua cd mdt cyc dai vio thing VIII, IX, mudn hon so vdi khu vye 1, va mpt cue tilu vip thing XII. Ba thing mua ddng (XII, I vi 11) ia thdi ky kh6 nhit vdi luong mua khong qui 30 mm/thing Dang chii y vao niia cuoi thing miia ddng thudng c6 hign tupng thdi tiet nom va raua phiin. Do die diem biln md v i dp cao dja hinh t h ^ nen khu vyc cd nguy co bi tic dpng rat manh ciia gid, bap. Toe dp gid trung binh dgt 2,2-3,6 m/s, cao ban so vdi nhieu nai khac trong vung nghien ciiu Miia hg trong khu vuc ciing dupc .gid biln lam diu bdt ning ndng va tang them nguon am, khdng khic nghiet nhu dong bing Trung bp. Toe dp gid cyc dgi cd gii tri cao (tren 40 m/s) trong thdi gian tu thing VII den X, Idn nhat cd the dgt 48 m/s do tgi trgm Van Ly vio thing IX. Trong then ky gid miia Ddng Bic thjnh hinh, toe dp gid cue dai kh6ngqui20m/s.
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HSi Dia ly Vi£t Nam Daii hgc Thii Nguygn
Hinh 2. Mdt sd ddc trung khi hdu do tgi cdc trgm d kliu vyc 2 Trai tren - Nhiet dp trung binh thing; Phii tren - So gid ning trung binh thing Trai dudi - Luang raua tnmg binh thing; Phii dudi - Toe do gid cue dgi cic thing Khu vyc 3
0 khu vyc 3, miia ddng bdt lgnh va la thdi ky rat am udt (khic bin vdi cac KVI va KV2, co thdi ky tuong doi khd vio dau mua ddng). Net n^i bit, vio dau mua hg cd thdi ky khd ndng lien quan den sy phit trien ciia gid phan phia Tay, lira sai I$ch dang ke dien bien mua mua am (miia mua am xe djch ve cuoi mua ha). Nhiet dp trung binh nam cao, thay doi tir 23,7''C den 24,3°C theo chieu tu Bac vao Nam. Bien trinh nhiet dp tnmg binh thing cd cue dgi vao thing VII v i cyc tieu vao thing I vdi bien dp khoang I2°C (Hinh 3). Khu vyc 3 la nai cd so gid nang Idn nhat trong viing nghien ciiu. Thdi gian chieu sang trong nam dgt tdi 1600-1700 gid, the hien nguln nang lupng m^t trdi khi doi dio cung cip cho sy phat trien cua thyc vgt; phan Idn cac thing trong nim deu cd tren 100 gid ning, cao nhit l i cic thing V - VII cd tren 200 gid; thing it ning nhat ciing dat tr§n 50 gid
Lupng mua trong khu vye 3 cd sy phan hda rd r?t. (3 phan phia Bic, thupc cac tinh Thanh Hda va Nghe An, lupng cue mua khoing 1700 - 2000 mm/nam vdi bien trinh mua khi giong khu vyc 2, cue dgi vio thing DC v i tilu vao thing XII hogc thing 1, ngoii ra cdn cd them mot cyc dgi phy vao tiling V. Phin phia Nam thupc tinh H i TTnh, do hi?u iing dja hmh ciia day mii Hoanh San, cd lupng raua rat cao, dat tdi 2600 mm/nam (tram Ha TTnh) tiigm chi 2800 mm/nam (trgm Ky Anh), day eiing l i mpt ti-png nhiing trung tam mua Idn cua Viet Nam. Biln trinh mua trong tiong nam d phin phia Nam cd cyc dgi vio thing X, cye tieu vao thing HI, thing IV, tre ban mpt tiling so vdi phan phia Bic. Ding chu y Iupng mua thing cyc dai d day rit cao dat tdi 700 - 750 mm, gap tcfi 1,5 - 1,8 lan so phin phia Bie. Ngogi trir Ky Anh, phan ldn khu vyc ed toe dp gid trung bmh thap, dgt 1,5-1,9 m/s, toe dp gid cyc dai ciing khdng qui 40 m/s. Toe do gio cyc dgi cd gii trj cao vao cic thing tii VH den X, day cimg la tiidi mua bao phat trien trong khu vyc. Cic tiling miia ddng, tir tiling XI den thing HI, gid Ddng Bic tiijnh hinh, toe dp gid cyc dgi tiiudng khdng qua 20 m/s.
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H0i Dia ly Viet Nam Dai hgc Thai Nguyen
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Hinh 3 Mdt sd ddc trimg khi hdu do tgi cdc trgm a khu vuc 3 Trai tren - Nhiet dp trung binh thing; Phii tren - Sd gid ning trung binh thing Trii dudi - Luang mua tnmg binh thing, Phai dudi - Toe do gid cyc dgi eic thing 5. A N H H U O N G CUA DIEU KIEN KHI HAU T O I T H U C VAT NGAP MAN Thyc vat ngE^ mgn ndi rieng ciing nhu thuc vat ndi chung chiu sy chi phoi manh me bdi che do nhiet am. Quan he Iupng mua R (mm) - nhiet dp T (°C) vdi qua trinh sinh trudng phat trien cua cay cd thi chia ra thinh 3 ^eu kipn nhu sau:
2T > R : dieu kipn khd hgn 2T < R < 100: dieu kien dii am R > 100: dieu kien thira am
Ngoai anh hudng qua moi quan he ke tren, cac dieu kien nhiet dp va luong mua quy dinh trac tiep cac ngudng sinh trudng v i phat triln cua thyc vat ngap mgn, Ve nhiet dp, theo tiiong ke cho thay RNM tren the gidi thudng phan bo d nhiing khu vyc cd nhiet do tnmg binh thing Ignh nhat Idn hon 20°C vi bien dp nhiet theo miia khdng vupt qua 10''C 4] Tuy nhien rung ng%) man CO thi phat trien den gidi ban dudng nhiet dp khdng khi thing lanh nhat la 16°C [4] Nhiet dd khoing 5°C v i suong muoi cung lim ban che sy phan bo eua RNM [4]. Nhiet dp khdng khi cd inh hudng Idn din su sinh trudng va so lupng loii thuc vat ngap man. Cae loai cay ngap man phong phu nhat va cd kich thudc Idn nhat thucmg d viing xich dgo va nhiet ddi am can xich dao, nai cd nhiet dp khdng khi trong nam cao v i bien dp nhiet hep. Nhiet dp thich hpp cho hogt ddng sinh Iy ciia Ii cic cay thyc vgt ngap man Ii 25 - 28°C [4] va cic hogt dpng nay giim &. rd ret khi nhiet tang vupt qua 35°C [4]. Theo tai heu cua Phan Nguyen Hong (1993), tirong ngay 18/IV/1990, nhiet dd len tdi 40°C trong khdng khi va 42°C trong dat da cho cic hoat dpng sinh Iy nhu thoat hoi nude, quang hpp ciia cay Dude (Rhizophora ^iculata). Tuong ty nhu vay, Millan (1971) phit hien thay mpt logt cay mim (Avicennia) bi chet 48 gid sau khi chju nhi^t dp 39 - 40°C Nhieu edng trinh nghien cim nude ngoai cho thiy ring doi vdi qui trinh quang hpp, nhiet dp tpi^uu la trong khoing 28-32°Cvadennhiptdp38 - 40°C thi qua trinh nay hiu nhu khdng cdn boat ddng [4],
Lupng mua cd inh hudng den sy sinh trudng, so lupng loii v i kich cd cay ng^ mgn. 0 viing nhiet ddi nhu T t i i Lan, Australia, Viet Nam, rimg n g ^ mgn phat tnin manh d nhung noi cd lupng mua trong nam cap (1800 - 25 OOmm); vimg it mua so lupng loai v i kich thudc cay giim [4]
Gid cd tac dyng tryc tiep hoac gian tiep den su hinh thanh cua rung n g ^ man theo nhieu cich. Gid Iam tang cudng dp thoit hoi nude, giup cho viec phat tin hgt va cay giong, lim thay doi
*E'nKngTiilirT;iTKmg~cMy-ven-bdrT^ phii sa, tram tich, tgo nen nhiing bai boi mdi, Ii noi cho nhung loii cay tien phong eua rimg n g ^ man phit trien. Gid mua Iam tang lupng mua, dem khdng khi lgnh (gid mua Ddng Bic) hogc khdng khi kho ndng (gid phan Tay Nam) inh hudng rat Idn din sy sinh trudng va phan bo cua thyc vat nhiet ddi ndi chung va cay n g ^ man ndi rieng.
Gid mgnh gay sdng Idn dgc bipt la khi cd bao tic dyng huy hoai true tiep cay coi cung nhu cac c&ig trinh ven bd.
Kyyiu Hdi nghi Khoa hgc Dia lp todn qudc ldn thu 7
Hoi Dia ly Viet Nam D^i hgc Thai Nguyen Ngoai cac yeu td khi hau neu tren, mpt so hien tupng thdi tilt dgc biet nhu bao, ddng, mua da, suong mu, suong mudi. cd inh hudng dang ke den rimg ngap mgn.
De dinh gia dilu kien khi hau doi vdi sy sinh tmdng va phat tnin ciia tiiuc vat ndi ehung, ciing nhu thuc vat ngap man ndi rieng cho mpt vung cu the can phai dua ra dupc cic dae tnmg sinh khi hau cua vimg dd. Xay dung cac bieu do sinh khi hau l i mot cich the hien rat ro rang cac dae tmng nay, phyc vy tdt cho vi^c danh gia cac yen td khi hgu nhim phit triln rimg ndi chung v i ning ngap man ndi neng. Tren bieu do smh khi hgu (Hinh 4) thudng tiie hien cic thdng so ve : nhiet, mua vi cic dieu kien ngumig lien quan din phat trien cua cay coi, do la .
Nhiet dp tmng binh nam, tong luang mua nam;
Dudng bien trinh nhiet dp va lupng mua tmng binh thing;
Cic thdi ky khd han, am, thira am;
Cic thdi ky cd nhiet dp toi thip tnmg binh thing dudi I5°C, nhiet dp toi thap tuy?t doi dudi 5°C, nhiet dp toi cao myet ddi tren 35°C;
Nhiet do toi cao tuyet doi, nhiet do toi cao trung binh thing ndng nhat;
Bien dp nhiet nam;
Nhiet dp tdi thip myet doi, nhipt dd tdi thip tnmg binh thing Ignh nhit.
Doi vdi dii ven bien Quing Ninh - Ha TTnh, cac bieu do sinh khi hau dupe xiy dyng tiieo so heu ciia 5 tram dai dien Mdng Cai, Bai Chay, Thai Binh, Quynh Luu v i Ha Tinh.
CHU THICH
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^ n r h c n Ky nhift d^ t6i th^p trung binh (hang diral 15°C
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^ ^ T h m ky ntiigt d$ t6i cao luy$l d6i (r^n 35'C
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Hinh 4. May bieu do sinh khi hgu va chii giai
6. DANH GlA DIEU KIEN KM HAU PHUC W PHAT TUIEN RlTNG N G A P M A N TH Q U A N G NINH DEN HA TTNH
, . , ^ ^ . ^ ^ ? ^ J » Q u i ^ Ninh_^Ha Tinh cd nhiet dp trung binh nam tiiay doi tir 22 5-24 5 X c6 kha nang phat tnen mng ngl^ mgn". t u y nhien neu xet vl nhipt do tnmg bmh tiiang Ignh nhat, tiii ehl CO duy nhat khu vjrc bic Quing Ninh (Mdng Cai - Tien Yen) ed nhiet do dudi 15°C la khong tiuch hpp cho phat tiien ririig nggp mgn. BiSn dp dao dpng nhiet dp nam d trong khu vuc 11-I3°C cao han chut it so vdi ngudng 10°C, cd phin nio lira giim su phit triln vl s6 Iupng, tiianh phin loai, kich thuae cay ngap man trong khu vuc so vdi cac nai khac d Viet Nam.
Lupng mua trong vimg nghien ciiu tiiay doi tir 1500 - 2800 mm/nam vdi tiidi ky cd lupng mua tiiang dat tren I OOmm kha dai, tmng binh 6 tiling, ca biet dat tdi 8 tiiang (Hi TTnh) hoan toin E i H f^yyeu Hgi nghi Khoa hgc Dia lp todn qudc ldn tha 7
Hpi Dia ly Viet Nara Dai hpc Thai Nguyen CO dli khi ning phat trien rimg ngap man. Tuy nhien chi cd hai khu vyc Bac Quing Ninh va Ha Tinh, nai cd lupng mua ldn (tren 2600 mm/nam) va khdng cd thdi ky khd ban, l i cd ^ l u kien rit thich hpp de phit trien rimg ngap man.
Rimg ngap mgn trpng khu vyc chju tic ddng phi hiiy cua bao va ap thap nhiet ddi vdi tin su^ 1,7 tran/nim ddi vdi khu vyc tir Quang Ninh den Thanh Hda va 0,8 tran/nam doi vdi khu vuc Nghe An - H i TTnh. Bao chii yeu tap trung vio cic thing VII, VIII, IX (chiem 77% tong so con bao cua vung). Trong so xoiy thugn nhiet ddi anh hudng den vimg nghien ciru thi ip thip nhiet ddi chilm ty le nhieu nhat (25%); bao manh cip 10 chiem ty le tuang doi Idn (18%); bao cap II trd Ien chi chilm ty Ie nhd (6-7%) song miic dp inh hudng cua nd Idn hpn rat nhieu. Hau qui ciia bao, ip thap nhiet ddi, ngogi trir tinh Quang Ninh dupc che chin bdi he thong dio thi cac tinh cdn Igi da timg ghi nhgn nhiing thiet hai nang ne khdng nhung doi vdi RNM ma cdn c i cic gia trj nhan sinh khic.
Ngoii nhung anh hudng ve dieu kien khi hau chung ke tren cho toin dii ven bien Quing Ninh - Hi TTnh, tiiy theo khu vyc cu the cdn cd nhirng thuan lpi va bit Ipi rieng vl mat khi hgu ddi vdi khdi phyc v i phit trien rimg nggp man. Dudi day la nhiing nhan xet tren ca sd phan tich cic bilu do sinh khi hgu dgi dien cho 3 khu vyc 1,2 vi 3 da dupc de cap d cic phan tmdc.
Khu vyc 1
Khu vyc I bao gom Quing Ninh va Hai Phong, die tnmg bdi kiiu khi hgu nhiet ddi gid miia cd mua ddng lanh, mua miia he (Hinh 5). Lupng mua tuang doi cao tao dieu kipn thyc vat phit trien. Miia ddng Ignh vdi I den 3 thing ed nhiet dp toi thip tnmg binh thing dudi 15°C la mdt bat Ipi phit trien thuc vat. Dang chii y trong khu vyc cd tdi 2 den 5 thing cd xuat hien nhiet dp toi thap xuong dudi 5°C, nhiet dp tpi thip xuong den khoang l''C lim nhieu loii cay khdng thich nghi ndi, cac loii khic thi bj kim ham ve kich thudc. Theo tai lieu ciia Phan Nguyen Hong et al. (1993), trong cac ngiy ngay 17 v i 18 thing I nam I96I mpt loat ciy Vet du (Bmguiere gymnorrhiza) v i Clerodendron inerme bj khd beo, ryng l i v i chet khi nhiet dp hg t h ^ xuong tdi 0°C Khac vdi phan phia bic Mdng Cai - Tien Yen ludn dii im v i thira am, d phin phia nam Hg Long - Hii Phdng cd miia khd ban trong khoing tir cuoi tiling XI den thing II, Igi tning vdi thdi ky nhiet do thap lgnh cing lam ban ehe khi ning smh tmdng v i phit tnen ciia cay.
Hmh 5 Biiu dd sinh khi hdu trgm Mdng Cdi vd Bdi Chdy
Di kem vdi thdi tiet Ignh, trong khu virc cdn xuit hien suong muoi vdi tin suit 0,3 ngay/nim (tgi Mdng Cai), thudng vio khoing thing XII, thing I trong nhung dpt gid miia Ddng bic mgnh.
Suang muoi xuat hipn khi nhipt dp khdng khi xu6ng rit t h ^ <4°C, v i nhiet dp mit dat gin xap xi 0°C. Suang muai la hipn tupng thdi tilt it gz^ nhung lai l i hien tupng thdi tiet nguy hiem dai vdi ciy trong, nhit la thdi gian suong mupi keo dii suong muoi lim cho cay khong cd khi nang quang hpp. ciy bj heo khd la va chet.
Kpyiu Hpinghi Khoa hgc Dia lp todn qudc ldn tha 7
Hoi Dia ly Viet Nam Oai hoc Thai Nguyen Ddi vdi nguang nhiet dp eao, khu vuc cd 4 den 5 thing cd the xuat hien nhiet dp tpi cao tren SS^C, lam anh hudng tdi cac boat ddng sinh ly va quang hpp cua thuc vgt nggp mgn song anh hudng nay ciing khdng nghiem trong vi nhiet dp khdng vuot qua 38°C, la nguang mi qua trinh quang hpp gin nhu ngimg hogt dpng
Khu vuc 2
Khu vyc 2 l i ven biln Thai Binh - Ninh Binh dupc die tmng bdi khi hau nhiet ddi gid miia CO mua ddng lanh, mua he, tiidi ky khd han keo dii tdi 3 thing (Hinh 6) Khu vuc nay ed I tiling nhiet dp tPi tiiip trung binh tiling dudi 15°C v i 1-2 tiling cd nhiet dp toi tiiip dudi 5°C nhung nhiet dp toi tiiip tuyet doi khdng xuong dudi 4°C nen inh hudng lanh do nhiet dp tiiip doi vdi thyc vat d day l i khdng Idn. Cic dilu kien luang mua nam (1677 mm) hai tiiip han so vdi ngudng phat trien tiiich hpp (>I800 mm), tiioi ky khd doi vdi chu ky sinh tmdng ciia cay keo dii 3 tiiang nhung lupng thilu am khdng ldn do vgy dilu kien mua, am trong khu vuc chi mang tinh chat giim bdt kha nang smh tmdng va phit tnin ciia cay. Dang luu y Ii khu vuc cd tdi 5-7 thing cd khi nang xuit hien nhiet dp tdi cao tren 35°C, ed nhieu thing nhi?t dp toi cap tren 38°C, ngudng ma qua trinh quang hop gin nhu ngimg boat dpng, va cyc dai cd the Ien tdi 39,2°C.
[52-52]
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1677 R(min}
VI VII vm IX
Hinh 6. Biiu dd sinh khi hdu tram Thdi Bkih Khu vyc 3
Khu vyc 3 bao gdm cac tinh tu Thanh Hda din Ha TTnh. Khi hau die tnmg cho khu vyc la nhiet ddi gid mua cd mua ddng Ignh, mua miia he (Hinh 7). Day l i khu vuc khdng edn chju tic dpng ciia dieu kipn thdi tiet Ignh cyc doan do nhi$t dp tpi thip tuyet doi Ii tren 5°C v i nhipt dp toi thip tnmg binh thing Ignh nhat tren 15°C.
Khdng chju^inh hudng cua cac ngudng nhipt dp thap song khu vyc Igi chju tic d$ng rat mgnh cic dieu kien nhiet dp cao do nim d vT dp thip ban so vdi cic khu vyc khac va ban thi lai co boat dpng mgnh cua gid Tay kho ndng, dgc biet la vao miia he. Thdi ky cd nhiet dp toi cao tren 3 5 °C rat dii til 7 den 10 tiiang, trong do cd 5 din 7 thing (trong khoang tir thing III den tiling IX) nhiet dp toi cao cd thi dgt 38 - 40°C cd anh hudng rat ldn tdi thyc vat nggp man.
Ky yiu Hgi nghi Khoa hgc Dia lp todn qudc ldn tha 7
H8i Dia ly Vift Nam Dai hoc Thii Nguyen
I » ^
Hinh 7. Bieu do sinh Mii hdu trgm Qupnh Luu vd Hd Tinh
Trong khu vuc cd sy khic biet vl luong mua giiia phin phia Bic v i phin phia Nam dan din sy khac biet d day ve che dp nhiet am. 0 phan phia Bic thupc cac tinh Thanh Hda v i Nghe An cd thai ky khd han doi vdi chu ky sinh tmdng cua cay keo dii cung lim anh budng den kha nang sinh tradng vi phit trien cua cay trong cac thing tir XII den thing III, Hon nira lupng raua d day khoing 1600 mm, hoi thip han so vdi ngudng toi uu, lira anh hudng tdi sy sinh tmdng, so Iupng loii vi kich cd cay n g ^ man. Q phin phia Nam thudc tinh Ha TTnh hoan toan nguac lai, Iupng mua rit cao, trSn 2500 mm, hoin toin du im va thira im, khdng cd thai ky kho ban nen rit thugn lpi cho phit trien ve so Iupng, thanh phin, kich cd cay coi ndi chung va cay nggp man ndi neng.
6. KETLUAN
RNM ven bien khdng chi cd y nghTa ve mat sinh thii trong viec dam bao khau trpng yiu trong chuSi thuc an, can bang sinh thii ma cdn cd y nglua tryc tiep treng bio ve cic gii tri tao dung ciia con ngudi vdi mgt dp ngay cang cao d khu vyc dja Iy nay. Chinh vi vay, viec phit triln v i bio V? RNM la rat can thiit, cd y nghTa song cdn doi vdi sy phit trien ben vung d khu vye ven biln Dudi day Ii mpt so n h ^ djnh lien quan den cdng viec bio ve va phit trien RNM dii ven biln Quing Ninh - H i TTnh, tren ca sd nghien ciiu hien trang RNM, die diem khi hiu, sinh khi hgu trong vimg.
- RNM d dai ven bien Quing Ninh - Ha Tinh chiem dien tich khdng nhieu song ed su phin hoa nhit djnh theo 3 khu vuc dja ly : Quing Ninh - Hii Phdng, Thii Binh - Ninh Binh va TTianh Hoa - Ha TTnh.
- Khi h%\x nhiet ddi gid mua, cd mua ddng Ignh, phan hda theo phuang kmh tuyin v i die diem dja hinh la yeu to quan trpng gdp phan tao ra sy phan hda RNM theo 3 khu vyc neu tren. Cic dgc thii ve sinh khi hgu cd nhung thuan lpi vi nhiing han ehl rieng doi vdi thyc vgt ngap man tiong tung khu vyc.
- Xet tren tong the toan vung tii Quing Ninh tdi Ha TTnh, che dp nhiet, che dp mua am, ve ca bin, cha phep phit triln rimg ngap man d day. Bien dp nhiet nam hon cao cd the lim ban che ve so Iupng, thinh phan loii, kich thude cay ng%) mgn trong khu vyc so vdi cic nai khac. Chi ed hai khu vyo-Bie-Quang ^Niah v i Ha TTnh cd dieu kien mua im toi uu de phat tnin rimg ngap mgn. Toin viing chju tic dpng mgnh cua bao v i ip thap nhiet ddi.
- (y khu vyc Quing Ninh - Hii Phdng, dieu kipn thdi tilt Ignh, day la khu vyc cd kha nang xuat hi^n suong muoi la nhung la nhiing yeu to ding luu y trong cong tie phit tnen rimg ngap man
- 6 khu vyc dong bang Bic Bp, thyc vat n g ^ man chju tie dpng tieu cyc cia cic dilu kipn:
thai ky khd hgn, thdi tiet lgnh, thdi tilt ndng song cung d miic dp viia phai khdng qua nghiem trpng nhu d cae khu vyc khic trong viing.
Kyyeu Hpi nghi Khoa hgc Dia lp todn qude ldn tha 7
Hoi Dia ly Viet Nam Dai hoc Thai Nguygn - 6 khu vuc Thanh Hda - Ha TTnh, cic dilu kien thdi tiet ndng cd anh hudng Idn den sy sinh tmdng vi phit tnin thuc vat ngap man. Phan Thanh Hda - Nghe An cdn phii trai qua tiidi ky khd han sinh ly ddi vdi tiiuc vat.
Cic nhgn dinh neu tren mdi chi xet dudi gdc dp khi hau, sinh khi hau. Diy l i mpt trong nhiing co sd khoa hpc gdp phan dinh hudng phit trien rimg ngap man, De ed mdt dinh hudng dung din, khoa hpc hem ein cd nhiing danh gia tiiem dudi gdc dp cic chuyen nginh khpa hpc khic./.
TAI LIEU THAM KHAO
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2. Ball M., 1988. Ecophysiology of mangroves. Trees 2, 129-142
3. Clough B.F., Andrews T.J. and Cowan I.R., 1982 Primary Productivity of Mangroves Australian Institute of Marine Science, Townsville, and Australian National University Press, Canberra, Australia.
4. Nguyen Khanh Van v i nnk (2000), Cic bieu do sinh khi hau Vipt Nam, Nxb Dgi hpe Quoc gia Ha Npi.
5. Lam Cdng Djnh (1992), Sinh khi hau irng dung trong Iam nghiep d Vi?t Nam, Nxb KH&KTHiNdi.
6. Ellison J , 2000. Tlow South Pacific mangroves may respond to predicted climate change and sea level rise', in Gillespie, A. and Bums, W. (eds). Climate Change in the South Pacific: Impacts and Responses in Australia, NewZealand, and Small Islands States. Kluwer Academic Publishers, Dordrecht, Netherlands, (ChapterlS), pp.289-301
7. Giiman E., EUison J.C, Duke N.C., Field C , Fortuna S., 2008. Tlireats to mangroves &om climate change and adaptation options: A review. Aquatic. Botany 89(2):237-250
8. Phan Nguyen Hong (I99I), Sinh thii thim thuc vat rimg n g ^ mgn Viet Nam, Lugn an Tien sy khoa hpc sinh hpc, chuyen nganh Sinh thii hpc.
9. Phan Nguyen Hong (1999), Rimg ngap mgn Vipt Nam, Nxb Ndng nghiSp HiNdi.
10. Nguyen Van Viet (2009), Tii nguyen khi hau nong nghiep Viet Nam, Nxb Ndng nghiep H i Npi.
11. Sd Ii?u luu trii, xu Iy tgi Phdng Khi hgu, Vien Dia Iy, Vi|n HLKH Viet Nam, 2012, 12. Ken W. Krauss, Catherine E. Lovelock, Karen L. McKee, Laura Lo pez-HoJEBnan, Sharon M.L. Ewe, Wayne P. Sousa, a Environmental dnvers m mangrove establishment and early development: A review. Aquatic Botany 89 (2008) page 105-127.
13. Dgng TTii Hdng Tliuy (2003), Khi tupng Nong nghiep, Nxb Dai hpc QuPC gia Ha n^i.
H.Tomlinson P. B., 1986. The botany of mangroves. Cambridge Univereity Press, Cambridge. 413 pages.
15. Phan Nguyen Hong, Hoang Thi San, 1993. Mangrove of Viehiam. lUCN. Bangkok.
Thailand
16. Millan, C. 1971. Environmental factors effecting seedlmg establishment of tiie black mangrove on the central Texas coast. Ecology 52: 927-930.
MjS^ Kyyiu Hdi nghi Khoa hgc Dia lp todn qudc ldn thd 7
