Effects Of Suaeda Glauca On Reproduction And Incubation Behavior Of Kentish Plover Charadrius Alexandrinus

Vegetation plays an important role in the life history of most birds,especially during the breeding stage.The ground-nesting birds either depends on the hidden effect of vegetation to avoid predators,or actively finds the threat close on the bare ground without shelter of vegetation,which is the trade-off between breeding birds avoiding predators and visual obstacles.Suaeda glauca is one of the most widely distributed vegetation types in the coastal area of Bohai Bay.The significance of this vegetation on the reproduction ecology of birds needs further study.In this study,a ground-nesting bird,Kentish plover(Charadrius alexandrinus),was studied in Liaohekou National Natural Reserve,China.We explored the nesting selection of Kentish plover between S.glauca and bare land habitats,and analyzed the effect of the vegetation on the reproduction and incubation behavior of the Kentish plover.The nest was monitored by infrared camera,and the type of predators and the time of predation were recorded.in addition,the predator enclosures cages were used to evaluate the protective effect of cages on the breeding success rate.Our results showed that:1.40%(n = 234)of the Kentish plovers were nested in S.glauca habitat,while60% of plover nested in mudflats or shell beaches.The apparent survival rate of the Kentish plover was 29.91%,and the nest daily survival rate(DSR)was 0.926.The nest success rate of the Kentish plover in the S.glauca habitat(20.7%;DSR: 0.907)was significantly lower than that in the bare land habitat(35.9%;0.937).2.The daily nest survival rates were estimated using RMark package.We found there was significant effect of habitat on the nest survival rate.Besides,the nest success was also significantly affected by the nest building material,breeding time,areas,and the interaction of nest material and habitat.The nest with S.glauca material has the lowest success rate(DSR: 0.859),while that of stone was the highest(0.961).The nest survival rate decreased continuously during the breeding season,and the nest survival rate in the protected area(0.906)was lower than that outside the protected area(0.969).3.The Eurasian Badger(Meles meles),and Siberian Weasel(Mustela sibirica)were predatorsx,and the nest predation(n = 30)occurred from 8: 00 p.m.to 4: 00 a.m.the photographic rate of predators in S.glauca habitat was not significantly different from that in bare land habitat.4.The nest survival rate of the nests with protective cages(DSR: 0.929)was higher than that in control nests(0.824),and the predation rate(50.6%)was lower than that of the control nests(70.4%).5.The Kentish plover nesting in the S.glauca habitat has a higher proportion of wakeful period than that in bare beach habitat;the proportion of time for the sleeping is lower than that in the bare beach habitat;the vigilance time and frequency are higher than that in the bare beach habitat.In the experiment of simulating S.glauca habitat in the bare land nests,the proportion of wakeful time in the experimental group was higher than that in the control group,the sleeping time decreased significantly,however,the vigilance time did not change.The Suaeda glauca,as a common vegetation type in Bohai Bay,can provide an important nesting habitat for certain number of Kentish plover.The S.glauca as nesting habitat and nesting material did not improve the nest success,but as the visual obstruction,which will impact the incubation behavior of Kentish plover.The predation from nocturnal mammal predators is the main reason for nest failure.Predator enclosures cages have a positively protective effect on the nest survival rate of Kentish plover,and can be used as a conservation management for the groundnesting birds breeding in the high nest predation habitat.