Ukuguquka kwesimo sezulu kungathinta izinhlobo eziningi zezilwane nezitshalo ngezindlela esingakwazi ukuzicabanga. Ukusuka ekuhlukaneni kwendawo yabo kuya ekushintsheni kwe-phenology nemijikelezo yabo, Ukuguquka kwesimo sezulu kudala izinguquko eziningi (ezinye zazo zingahlehliseki) ezinhlotsheni eziningi emhlabeni jikelele.
Kulokhu sizokhuluma ngendoda ye- i-flycatcher ehlanganisiwe. Inyoni enebala elimhlophe ekhanda layo ibaluleke kakhulu ekukhiqizeni nasekuhlanganiseni kwayo. Ukuguquka kwesimo sezulu kuyithinta kanjani le nyoni eyigugu?
Isu le-Collared Flycatcher
Eyesilisa yeCollared Flycatcher inayo indawo emhlophe ekhanda futhi ibaluleke kakhulu ekusesheni kwakho owesifazane. Lapho ibala lisekhanda likhudlwana, likhanga ngokwengeziwe kwabesifazane futhi maningi amathuba okuthi bakudlulise kuzakhi zofuzo zabo. Lokhu bekulokhu kunjalo kuze kube phakade. Kodwa-ke, emashumini eminyaka adlule, kukhona okushintshile.
Ukuguquka kwesimo sezulu kuyiphazamisa kabi le nyoni. Ikwenza lokho ngendlela yokuthi kusinde eyeduna enendawo encane kunazo zonke ngaphezu kwalezo ezinamabala amakhulu futhi bathola inzalo eningi.
I-Collared FlycatcherUFicedula albicollis) iyinyoni edlulayo, eyaziwa njengezinyoni. Alidluli ku-18 amagremu ngesisindo, lakha izidleke enyakatho nasenkabeni yeYurophu, lapho libalekela khona lapho kuphela ihlobo, likhosela e-Afrika. Iveza ukufiphala okuhle kwezocansi. Izinsikazi zinombala ompunga, kanti ezeduna zihlanganisa okumnyama nokumhlophe kube sengathi imikhomo ebulala noma ama-pandas. Ngaphezu kwalokho, baletha indawo emhlophe ngaphambili kwekhanda, ngenhla komlomo. Usayizi omkhulu wale ndawo uhlobene ne- ukuphatha insimu enkulu namathuba amakhulu okuheha abesifazane nokuzala.
Ochwepheshe balezi zinyoni sebeneminyaka engama-36 bezicwaninga. Izikhathi zokuqala ababanjwa futhi baboshwa ngamabhande, babeqinisekisa impumelelo yokuzala abayithokozelayo ngokuba nendawo enkulu eyinhloko. Kodwa-ke, maphakathi nawo-90, izinto zaqala ukushintsha futhi zashesha kule minyaka eyishumi edlule.
Ukuncipha kwebala
Engxenyeni yesibili yezifundo ezenziwa ngochwepheshe, kutholakale ukuthi abesilisa abanendawo encane kakhulu engaphambili usinde isikhathi eside futhi ube nenzalo eningi. Kulinganiselwa ocwaningweni ukuthi ukwehla kwebala kuba 11% ngaphansi. Okubahehe ngukuthi bebengazi noma bahlobanise ukuncipha kwendawo nekhono labo lokuzivumelanisa nezinyoni ngokwabo nalabo abanendawo encane kunazo zonke. Kepha bekungenangqondo ngoba engxenyeni yokuqala yocwaningo, yibo abanebala elikhulu kunawo wonke abasindile.
Kodwa-ke, manje osukwini lwanamuhla, abadobi bezintambo ezinamabala amancane manje sebenezindawo eziningi futhi baheha abesifazane abaningi.
Yini eshintshile?
Ochwepheshe baphathe ukuguquguquka okuningi ukuchaza ukwehliswa kwendawo ekhanda. Kepha bahlala nalabo abahlobene nokushintsha kwesimo sezulu. Ngoba amazinga okushisa omhlaba avukile kusuka ngawo-80 kuya namuhla, emithonjeni efudumele (ngesikhathi sokuqomisana nezinyanga zokukhwelana) izinyoni zenza kangcono ngamabala amancane. Kungakho ukuguquguquka kwesimo sezulu bekuzodala ingcindezi yokukhetha ivuna labo abanesiphiwo esincane.
“Asinaso isiqiniseko sokuthi yini edala umehluko wokuqina, ngaphambi noma manje. Mhlawumbe ukuguquguquka kwesimo sezulu sekwenze kwaba nzima ukufuya lezi zinyoni, ikakhulukazi ngoba kumele zithuthele e-Afrika. Lokhu kungasho ukuthi abesilisa abanamabala amakhulu kunabo bonke kufanele basebenze kanzima manje: ngaphezu kokondla amaphuphu abo, laba besilisa babandakanyeka ekulweni okuningi nabanye abesilisa. Kubuyela emuva empumelelweni yokuzala. Izindawo ezinkulu ziheha abesifazane, kodwa futhi nezinselelo zabesilisa. " Ongoti balezi zinyoni bayaphawula.
Njengesiphetho kudonswa lokho ukuqhubekela phambili kokokuqala nokunyakaza okuya enyakatho yimiphumela emibili yokuguquka kwesimo sezulu ethinta kakhulu izinyoni.