Ukuguquguquka kokuziphatha kanye nokushintsha kwe-trophic niche: Indlela amahansi asebusika asabela ngayo ekushintsheni kwendawo yokuhlala.

Ijenali:I-Freshwater Biology, 64(6), amakhasi 1183-1195.

Izinhlobo (zezinyoni):Ihansi lebhontshisi (i-Anser fabalis), ihansi elimhlophe elingaphansi (i-Anser erythropus)

Isifinyezo:

Izinga elisheshayo lokushintsha kwemvelo okubangelwa abantu liletha inselele enkulu ezilwaneni zasendle. Amandla ezilwane zasendle okuzivumelanisa nezinguquko zemvelo anemiphumela ebalulekile empilweni yazo, ekusindeni kwazo, nasekuzaleni. Ukuguquguquka kokuziphatha, ukulungiswa okusheshayo kokuziphatha ngenxa yokuguquguquka kwemvelo, kungaba kubaluleke kakhulu ekubhekaneni noshintsho olubangelwa abantu. Inhloso eyinhloko yalolu cwaningo kwakuwukulinganisa impendulo yezinhlobo ezimbili zamahansi asebusika (ihansi lebhontshisi i-Anser fabalis kanye nehansi elimhlophe elingaphansi i-Anser erythropus) esimweni esibi sendawo yokuhlala ezingeni labantu ngokutadisha ukuziphatha kokuzifunela ukudla. Ngaphezu kwalokho, sihlole ukuthi ukuqina kokuziphatha kungashintsha yini indawo yokuhlala. Sichaze ukuziphatha kokuzifunela ukudla futhi sabala ububanzi basekhaya bansuku zonke (HR) bamahansi sisebenzisa idatha yokulandelela uhlelo lokuma komhlaba wonke. Sibale izindawo ezijwayelekile ze-ellipse ukuze silinganise ububanzi be-niche sisebenzisa amanani e-δ13C kanye ne-δ15N amahansi ngamanye. Sixhumanise ukuqina kokuziphatha nekhwalithi yendawo yokuhlala sisebenzisa amamodeli e-ANCOVA (ukuhlaziywa kwe-covariance). Siphinde sahlola ukuhlangana phakathi kwezindawo ezijwayelekile ze-ellipse kanye ne-HR sisebenzisa imodeli ye-ANCOVA. Sithole umehluko omkhulu ekuziphatheni kokuzifunela kwamahansi phakathi kweminyaka endaweni yawo yokuzifunela yansuku zonke, ibanga lokuhamba kanye nesivinini, kanye ne-engeli yokujika. Ngokukhethekile, izinyoni zandisa indawo yazo yokuzifunela ukuze zanelise izidingo zazo zansuku zonke zamandla ngenxa yezimo zendawo yokuhlala ezimbi. Zazindiza kakhulu futhi zihamba amabanga asheshayo nakude nsuku zonke. Kumahansi amhlophe asengozini yokuqothulwa, zonke izinguquko zokuziphatha zazihlotshaniswa nekhwalithi yendawo yokuhlala. Kumahansi ebhontshisi, i-HR kanye ne-engeli yokujika kuphela ezazihlobene nekhwalithi yendawo yokuhlala. Izinyoni, ikakhulukazi ihansi elimhlophe elingaphansi, kungenzeka ukuthi zazinesimo esiphakeme se-trophic ngaphansi kwezimo ezimbi. Okutholakele kwethu kubonisa ukuthi amahansi asebusika abonise izinga eliphezulu lokuziphatha kahle. Kodwa-ke, ukuziphatha kokuzifunela okusebenzayo ngaphansi kwesimo sendawo yokuhlala embi akuzange kuholele endaweni ebanzi ye-trophic. Ukutholakala kwendawo kungaba yimbangela yezimpendulo ezihlukene zokuzifunela amahansi kanye nendawo ye-isotopic ekushintsheni kwemvelo okubangelwa abantu. Ngakho-ke, ukugcina izindlela zemvelo zamanzi ngesikhathi esibucayi (okungukuthi uSepthemba-Novemba) ukuqinisekisa ukuthi izinsiza zokudla ezisezingeni eliphezulu ziyatholakala kubalulekile ekusaseni labantu bamahansi ngaphakathi kwe-East Asian-Australasian Flyway.