Kogin mangroves na Delta na Nijar

Najeriya tana da gandun daji masu yawa a yankin bakin teku na Neja Delta . An dauke shi daya daga cikin yankuna masu mahimmanci a duniya, gandun daji na mangrove na Niger Delta yana cikin yanayin da ke cikin deltaic. Wadannan gandun daji na mangrove suna taka muhimmiyar rawa a cikin yanayin muhalli da yanayin ƙasa, kuma suna tallafawa ayyukan tattara abinci, da kuma damar samun kudin shiga ta kasuwa. 

 Bayani na gaba ɗaya 
Ana samun gandun daji na mangrove a cikin ƙasashe 118 da yankuna a duk duniya,  75% na yankunan ciyayi na mangrover suna cikin wuraren zama na wurare masu zafi da ke tsakanin 25 ° N da 25 ° S. Yawanci kewaye da kogin kogin, yankunan mangrove suna tallafawa halophytes iri-iri. Wadannan tsananin shrubs da bishiyoyi, wadanda suka saba da sauye-sauyen yanayin bakin teku (kamar ambaliyar ruwa, hasken rana, ƙasa mai narkewa, da kuma yawan gishiri), suna taka muhimmiyar rawa wajen noma bambancin halittu da jin daɗin yanayin da ke kewaye.

Kogin mangrove na Nijar Delta shine na uku mafi girma a duniya kuma mafi girma a Afirka. Tun daga shekarun 1960 binciken mai da iskar gas ya zama muhimmin aikin tattalin arziki, wanda ya haifar da canji mai mahimmanci na wuri mai faɗi ta hanyar gurɓataccen yanayi, birni da mamayewa.

Mangroves na Afirka sun fuskanci manyan kalubale a cikin 'yan kwanakin nan, suna fuskantar asarar gaske. Raguwa, lalacewa, da lalacewar gandun daji na mangrove za a iya danganta su da dalilai da yawa kamar birni, dutse, gishiri da yashi, gurɓata daga masana'antu da sinadarai na masana'antu, da kuma man fetur da amfani da iskar gas. Bugu da ƙari, rashin isasshen doka da sare daji don shan sigari na kifi yana taimakawa ga wannan batun. Yankin gandun daji na mangrove a Najeriya ba wai kawai yana inganta wadatar zamantakewa da tattalin arziki na yankunan karkara na bakin teku ba amma kuma yana da alkawarin kare su daga mummunan yanayi wanda ya kara tsanantawa ta hanyar canjin yanayi. Ana sa ran hauhawar da ake tsammani a cikin matakan teku zai kara ambaliyar ruwa a yankunan bakin teku a ƙananan tsaunuka, sannan ya kara karfin jiki da zamantakewar tattalin arziki na cibiyoyin birane na bakin teku. An amince da Najeriya a matsayin daya daga cikin kasashe na Afirka da suka fi saukin kamuwa da canjin yanayi, kuma tasirinsa a halin yanzu yana bayyana a yankuna daban-daban na kasar.Giri, C. et al. Status and distribution of mangrove forests of the world using earth observation satellite data. Glob. Ecol. Biogeogr. 20, 154–159 (2011).

A Najeriya, akwai fiye da wuraren masana'antu 2,000, tare da kusan 80% daga cikinsu sun fi mayar da hankali a yankunan bakin teku, musamman a cikin birane kamar Legas, Port Harcourt, da yankunan da ke kusa. Masana'antu a yankin bakin tekun Najeriya sun kunshi bangarori da yawa ciki har da man fetur da iskar gas, man fetur, ƙarfe da ƙarfe, tsire-tsire masu amfani da taki, tsire'o'in narke aluminum, da masana'antun masana'antu daban-daban kamar masana'antu, sarrafa abinci, filastik, magunguna, samar da siminti, samar da sabulu da kayan wankewa, samar da fenti, yin giya, da katako da takarda.Giri, C. et al. Status and distribution of mangrove forests of the world using earth observation satellite data. Glob. Ecol. Biogeogr. 20, 154–159 (2011).

 Abubuwan da ke tattare da halittu 
A fannin halittu, nau'ikan mangrove guda shida sun hada da wadannan gandun daji, gami da nau'ikan nau'ikan guda uku a cikin dangin  (Rhizophora racemosa)  (ja mangrove; tsayi),, Rhizophora harrisonii (ja mangriove; dwarf), Rhizophora mangle (ja mangreove; dwarfi), da nau'in a cikin danginsa Avicenniaceae (farin mangrove) da Combretaceae. Daga cikin wadannan nau'o'in, Rhizophora racemosa ya mamaye mafi yawan gandun daji, yana da kusan kashi 90% na duk mangrove biota. Duk da fadada yanayin ƙasa, gandun daji na mangrove na Neja Delta yana da kusan 80% na ciyayi da aka rarraba a jihohi uku (Bayelsa, Delta, da River).

Kodayake gandun daji ya ƙunshi nau'ikan mangrove guda shida, ci gaban mangrove ya samo asali ne a cikin bankunan rafi mai laushi. Nazarin ya nuna cewa RhizophoraR. racemosa''' (wanda shine mafi tsayi na nau'in mangrove) ya kai ga ingantaccen damar girma lokacin da aka fallasa shi ga ruwa mai laushi da laka mai laushi, yayin da dangin R. racemosa, R. mangle da R. harrisonii,'' suna son salinity mafi girma da laka mai wuya. A cikin yanayin halitta, ƙasar mangrove ko "chikoko" (haɗewar acid sulphate, yumbu mai laushi, yumbu da peat), yana da pH na 4 da 6 don mangroves da ke zaune a wurare masu saurin ruwa da tsaunuka masu tsawo, bi da bi. Idan matakan salinity sun sauya yawa daga waɗannan matakan, laka sun zama marasa dacewa ga samar da mangrove, kuma tsarin sake gina mangrove (daga ƙasar mangrove mai amfani zuwa mangrove masu samarwa) na iya ɗaukar sama da ƙarni ɗaya.

 Rarraba mangroves a Najeriya 
A yankunan bakin teku na Najeriya, an rarraba gandun daji kamar haka:

 Legas, wani yanki na bakin teku a Najeriya, yana da jimlar murabba'in kilomita 42.20. A cikin wannan yanki, musamman murabba'in kilomita 3.13, an sanya su a matsayin wuraren ajiyar gandun daji. Wannan ɓangaren a cikin ajiyar gandun daji yana wakiltar kashi 7.42% na yankin Legas gaba ɗaya. Ainihin, wannan yana nuna cewa an sanya wani karamin amma mai mahimmanci na Legas a matsayin ajiyar gandun daji, yana ba da gudummawa ga adanawa da kiyaye wuraren zama da yanayin halittu na yankin.
 A cikin Ogun, wani yanki a Najeriya, jimlar yankin da mangroves suka rufe shi yana da murabba'in kilomita 12.18. Abin sha'awa, ba kamar wasu yankuna ba, babu wuraren mangrove da aka tsara musamman a cikin gandun daji a wannan yankin. Wannan yana nuna cewa duk mangroves a cikin Ogun suna cikin wuraren da ba a ajiye su ba, ba su da alamar kariya ta ajiyar gandun daji. Wannan halin na iya haifar da tasirin kokarin kiyayewa kuma yana nuna cewa kiyaye mangrove da gudanarwa a cikin Ogun na iya buƙatar dogaro da wasu nau'ikan kariya da shirye-shiryen dorewa fiye da wuraren da aka tsara.
 A yankin Ondo, Najeriya, mangroves sun rufe yanki na murabba'in kilomita 40.62. Koyaya, ba kamar wasu yankuna ba inda za a iya rarraba mangroves a cikin wuraren ajiyar gandun daji don kariya da gudanarwa, Ondo ba shi da wuraren mangrove da aka tsara a cikin wuraren da aka tanada gandun daji. Wannan yana nufin cewa duk mangroves a Ondo suna waje da wuraren ajiyar gandun daji da aka tsara a hukumance. Wannan rashin mangroves a cikin wuraren ajiyar gandun daji na iya rinjayar tsarin kiyayewa da gudanarwa ga waɗannan mahimman yanayin halittu a Ondo. Adana mangroves a wannan yankin zai iya buƙatar wasu dabarun da ƙoƙarin da aka yi niyyar kare su a waje da ƙayyadaddun ajiya. Ya jaddada muhimmancin matakan kiyayewa da ayyuka masu ɗorewa don tabbatar da ci gaba da lafiya da kuzari na mangroves a Ondo.
 A cikin yankin Edo / Delta na Najeriya, yankin gandun daji na mangrove ya rufe murabba'in kilomita 3,470.32. A cikin wannan yanki mai faɗi, murabba'in kilomita 143.75 na mangroves suna cikin wuraren ajiyar gandun daji da aka tsara. Wannan yana nuna cewa kusan kashi 4.14% na jimlar yankin mangrove an kare shi a hukumance a cikin waɗannan wuraren ajiyar gandun daji. Samun wani ɓangare na yankin mangrove a cikin wuraren ajiyar gandun daji yana da mahimmanci don kiyaye su da kuma gudanarwa mai ɗorewa. Yankunan gandun daji suna aiki ne a matsayin yankuna masu kariya inda ayyukan da ke da lahani ga mangroves, kamar katako ba tare da nuna bambanci ba ko lalata mazaunin, ana tsara su ko hana su. Wannan yana taimakawa wajen kula da ma'aunin muhalli da kuma nau'ikan tsire-tsire da dabbobi daban-daban waɗanda suka dogara da tsarin halittu na mangrove.
 A cikin yankin Rivers / Bayelsa na Najeriya, yankin gandun daji na mangrove ya kai murabba'in kilomita 5,435.96. A cikin wannan faɗin mai faɗi, an sanya murabba'in kilomita 90.62 na mangroves a cikin wuraren ajiyar gandun daji. Wannan yana nuna cewa kusan 1.67% na jimlar yankin mangrove an kiyaye shi a cikin waɗannan takamaiman wuraren ajiyar gandun daji.
 A cikin yankin Cross River / Akwa Ibom, gandun daji na mangrove ya mamaye yanki mai faɗi na murabba'in kilomita 721.86, kuma a cikin wannan faɗin, murabba'i kilomita 67.19 sun fada ƙarƙashin kariya na wuraren ajiyar gandun daji, wanda ya kai 9.31%. Gabaɗaya, idan aka yi la'akari da dukkan yankuna, jimlar yankin gandun daji ya kai murabba'in kilomita 9,723.14, tare da murabba'i kilomita 304.69 da aka tsara a cikin wuraren ajiyar gandun daji.

 Rayuwar zamantakewa da muhalli 
dazuzzukan mangrove na Neja Delta suna taka muhimmiyar rawa ga kashi 60% na mutanen yankin da ke dogaro da ƙasa da teku don rayuwa. dazuzzuka suna ba da gudummawa ga warkarwa, jin daɗi, gado, ruhaniya, da dabi'un rayuwa. Amsoshi daga binciken da aka gudanar a cikin 2007 da 2008 kimanta darajar zamantakewar mangrove a cikin al'ummomin Niger Delta guda uku sun nuna kusan kashi 85% na iyalai masu halarta a baya sun yi amfani da ciyayi na mangrove azaman magani kuma tsakanin kashi 65% da 71% na mazauna ƙauyen sun gane gandun daji a matsayin wurin hutawa. Gidan mangrove na Neja Delta kai tsaye (ta hanyar albarkatun kasa) da kuma kai tsaye (ta hanyar samfuran da ke cikin gandun daji) suna ba da albarkatun tattalin arziki ga yankunan karkara da birane na Najeriya, tare da takwas daga cikin goma mafi yawan ayyukan da suka dogara da yawan jama'ar mangrove masu tasowa. Wadannan ayyukan sun hada da zane-zane na jirgin ruwa, katako, girbi katako, gini, kamun kifi, katako na gargajiya, da kasuwanci.

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