Why the crested ibis declined in the middle twentieth century

Abstract

The crested ibis (Nipponia nippon) had declined severely from a common species to only two pairs in last century. To analyze the declining process, we established a GIS database with historical occurrences of the crested ibis based on published literatures, and layers of environmental factors such as elevation, wetland, and human activities. We compared the environmental factors at the occurrence sites in diVerent periods to quantify the changes of habitat use across time. To address the spatial deviation of the occurrences and check the eVect of measuring scale on habitat use, we calculated the environmental factors in a serial measuring scales from 1 to 161 £ 161 km 2 . Our results indicated that the crested ibis traditionally lives in habitat with higher wetland density and higher human impact, then it gradually moved to areas with higher elevation and lower human impact in last century. In 1980-2000 the crested ibis stayed at a very high elevation, lower wetland density and lower human impact as possible consequences of human activities such as using fertilizer and pesticide, drying the over wintering rice paddies, and direct hunting. Our quantitative analysis of the habitat use matched well the previous published statements (which have no numerical evidences) on the declination of the crested ibis. We suggest to reestablish the habitat with traditional farming practice that the bird has adapted as a major solution for applications such as conservation planning and reintroduction.

Using Bayesian hierarchical models and random forest algorithm for habitat use studies: a case of nest site selection of the crested ibis at regional scales

“…In general, our results are consistent with previous studies (e.g., Li et al 2002a; 202 Li et al 2006;Li et al 2009;Zhao et al 2010) that the area of rice paddy and the area …”

“…The population size of the crested ibis had been declined severely in the mid-19 th 54 century (Li et al 2009) to only two pairs and three nestlings in 1981 (Liu 1981). Now The crested ibis is an ideal species for studying the integrative habitat preference has generated sufficient occurrence data.…”

Flexivirga lutea sp. nov., isolated from the faeces of a crested ibis, Nipponia nippon, and emended description of the genus Flexivirga

“…Nevertheless, the crested ibis has thrived in northeast Asia. The number of crested ibis rapidly declined during the late 19th century to early mid-20th century, and these birds were listed as an endangered species (Li et al, 2009). Thus, at present, only a few populations are preserved in the wild and in zoos in Korea, China and Japan.…”

Decline of traditional rice farming constrains the recovery of the endangered Asian crested ibis (Nipponia nippon)

“…Apart from a few records of the historical distribution of this species, previous studies on reproduction (Yu et al 2006), foraging and breeding habitat selection Liu et al 2003), population dynamics and demography (Wang and Li 2008), and conservation strategies (Xi et al 2002;Su 2008) in wild crested ibis have been conducted based on this rediscovered and recovering population. Scientists attributed the dramatic decline of the crested ibis population in the mid-twentieth century to the combined influence of habitat loss (due to changing farming practices) and the high risk of human-induced mortality (due to hunting and use of toxic pesticides) (Li et al 2009;Ding 2010). Consequently, intensive conservation efforts have been made to prohibit hunting and deforestation, to monitor the nesting habitats, to prevent predation, and to limit or prohibit the use of agrochemicals over the past 30 years (Xi et al 2002;Su 2008).…”