Ijenali:I-Freshwater Biology, 64 (6), pp.1183-1195.
Izinhlobo (Izinyoni):Ihansi likabhontshisi (Anser fabalis), Ihansi elinengaphambili elincane elimhlophe (Anser erythropus)
Abstract:
Izinga elisheshayo lokushintsha kwemvelo okubangelwa abantu libeka inselele enkulu ezilwaneni zasendle. Ikhono lezilwane zasendle lokuzivumelanisa nezinguquko zemvelo linemiphumela ebalulekile ekuqineni kwazo, ukusinda, nokuzala kwazo. Ukuguquguquka kokuziphatha, ukulungiswa okusheshayo kokuziphatha ekuphenduleni ukuhlukahluka kwemvelo, kungase kubaluleke kakhulu ekubhekaneni noshintsho lwe-anthropogenic. Inhloso enkulu yalolu cwaningo kwakuwukulinganisa ukusabela kwezinhlobo ezimbili zamahansi asebusika (ihansi likabhontshisi Anser fabalis kanye nehansi elincane elingaphambili elimhlophe i-Anser erythropus) esimweni esibi sendawo yokuhlala ezingeni labantu ngokufunda ukuziphatha kokudla. Ngaphezu kwalokho, sihlole ukuthi ipulasitiki yokuziphatha ingashintsha yini i-trophic niche. Sinezimpawu zokuziphatha kokudla futhi sabala uhla lwasekhaya lwansuku zonke (HR) lwamahansi sisebenzisa idatha yokulandelela isistimu yokuma komhlaba. Sibale izindawo ezijwayelekile ze-ellipse ukuze silinganise ububanzi be-niche sisebenzisa amanani angu-δ13C kanye no-δ15N wamahansi angawodwana. Sixhumanise ipulasitiki yokuziphatha nekhwalithi yendawo sisebenzisa i-ANCOVA (ukuhlaziywa kwamamodeli we-covariance). Siphinde sahlola ukuhlobana phakathi kwezindawo ezijwayelekile ze-ellipse kanye ne-HR sisebenzisa imodeli ye-ANCOVA. Sithole umehluko omkhulu ekuziphatheni kokudla kwamahansi phakathi kweminyaka endaweni yawo yokudla kwansuku zonke, ibanga lokuhamba nesivinini, kanye ne-angle yokujika. Ngokukhethekile, izinyoni zandisa indawo yazo yokudla ukuze zanelise isidingo sazo sansuku zonke samandla ngenxa yezimo ezingezinhle zendawo yokuhlala. Zazindizela ngobubi kakhulu futhi zihamba amabanga amade nsuku zonke. Kumahansi amhlophe angaphambili asengozini yokushabalala, zonke izinhlobo zokuziphatha zazihlotshaniswa nekhwalithi yendawo yokuhlala. Kuhansi kabhontshisi, i-HR kuphela kanye ne-engeli yokujika ehlotshaniswa nekhwalithi yendawo yokuhlala. Izinyoni, ikakhulukazi ihansi elincane elimhlophe ngaphambili, kungenzeka ukuthi libe nendawo ephezulu ngaphansi kwezimo ezimbi. Esikutholile kukhombisa ukuthi amahansi asebusika akhombisa izinga eliphezulu le-plasticity yokuziphatha. Kodwa-ke, ukuziphatha okusebenzayo kokudla ngaphansi kwesimo esingesihle sokuhlala akuzange kuholele ku-trophic niche ebanzi. Ukutholakala kwendawo yokuhlala kungaba nesibopho ezimpendulweni ezihlukene zokufuna i-HR kanye ne-isotopic niche ekushintsheni kwemvelo okwenziwe abantu. Ngakho-ke, ukugcinwa kokulawulwa kwamanzi okungokwemvelo ngesikhathi esibucayi (okunguSepthemba–Novemba) ukuze kuqinisekiswe ukuthi imithombo yokudla yekhwalithi iyatholakala kuyisisekelo sekusasa lamahansi ngaphakathi kwe-East Asian-Australasian Flyway.
OKUSHICILELAYO OKUTHOLAKALA KWA:
https://doi.org/10.1111/fwb.13294
