Ningshan Crested Ibis (Nipponia Nippon) Reintroduction Born Diffusion Population

Dispersal was defined as a linear spreading movement of individuals away from others of the population by Greenwood and Harvey in1982. It included natal dispersal that dispersal from the site or group of birth to that of first reproduction or potential reproduction, and breeding dispersal that subsequent movement between breeding sites or groups. Dispersal is a fundamental characteristic of animals in nature, a movement of organisms and a important research in Ecology, Ethology and Evolutionary Biology. Recently Dispersal Ecology has been a new part of Ecology as popularity of dispersal study around the world. Avian is one of the groups which are studied intensively by human beings. Dispersal studies on avian species represent a new frontier of ornithological research.The Crested Ibis (Nipponia nippon) was listed as a first grade national protected species and endangered species on the IUCN Red List. Their natural ranges have widely spread out eastern Asia in the early20th. They were once one of eastern Asia’s most familiar birds. However, the human-influences and climate change led to devastating destruction of their habitat and significant populations decline since the middle of the20th. The Crested Ibis was successive extinction in many areas around the world. Only7individuals worldwide of wild population were rediscovered in Yangxian, Shaanxi Province in1981. Subsequently, the in-situ, ex-situ conservation and reintroduction have been taken in order to restore and establish a new colonizing population which can make it sustainably and steadily for reproducing during the past30years and received a great success. Their wide population has increased from7to approximately1,440. A reintroduction program of the Crested Ibis was launched at Zhaigou Village, Ningshan County in Shaanxi Province in May2007. Until2012, the released individuals have added up50,25adults were monitored in the wild, about10pairs were formed,27clutches (86eggs) were produced and47nestlings had fledged successfully. All indicated that the first reintroduction program in the world has achieved one of its first targets.We conducted fieldwork for natal dispersal of11ibis individuals reproduced in Ningshan County from2009to2013. Their natal dispersal distance and dispersal direction was collected used by GPS. Subsequently, the gender difference of natal dispersal distance and the link between age and distance was analyzed by SPSS. The mean dispersal vector (μ) of dispersal direction showed their potential dispersal movement and group distribution.6males’mean dispersal distance was6.14±6.95km (n=6).5females’mean dispersal distance was32.84±35.01km (n=5). The data showed there was a significant difference of dispersal distance between two genders (Mann-Whitney Test:Z=-1.676, P=0.036). The female dispersal distance was significantly longer than the male. The analysis consequence suggested the Crested Ibis’s natal dispersal model in reintroduced population of Ningshan Country was female biased dispersal, like most of other monogamy birds.The mean first breeding age of recorded individuals was2.09±0.54(n=11). The males’mean first breeding age was2.00±0.0(n=6), the females’mean first breeding age was2.20±0.84(n=5). Our recorded individuals had three groups of age. The mean dispersal distance was2.43±0.00km (n=1) in one age group. The mean dispersal distance was22.05±30.75km (n=8) in two age group. The mean dispersal distance was11.09±1.11km (n=2) in three age group. There were significant differences between this three group respectively (Chi-square Test:K2=6.149, df=2, P=0.046).The recorded individuals’dispersal direction was tested by Oriana4.01. The length of mean dispersal vector (r) was0.42. The Rayleigh’Z was1.414(P<0.05). The mean dispersal vector (μ) was224.65°±75.48°. The tendency of their dispersal direction was roughly southwest. Their dispersal moved along to Changan River (the secondary tributary of Hanjiang River) from north to south (Fig.3-l-Fig.3-11).At last, we studied the dispersal of reintroduced population in Ningshan County compared with the wild population in Yangxian County. The consequence showed that the dispersal model of reintroduced population was similar to the wild population. They were both female biased dispersal. In addition, the mean dispersal distance of female was significantly longer than male in the two populations. The dispersal directions were slightly different between the reintroduced and wild population. The dispersal directions were southwest and southeast in reintroduced and wild population, respectively. We summarized the factors resulted in the difference between this two population were the different landscape in two areas and the colonies in autumn and winter.