Trace elements exposure of endangered crested ibis (Nipponia nippon) under in situ and ex situ conservations

Crested ibis (Nipponia nippon), one of the rarest birds in the world, was almost extinct in the historically widespread areas partly due to the environmental pollution. Therefore, non-invasive indicators of feather, eggshell, and excrement were used to investigate the exposure of this endangered bird to eleven trace elements in this study. The results indicated that crested ibises under in situ and ex situ conservations were diversely exposed to trace elements, with higher exposure levels of As, Cd, and Mn in the wild, but higher exposure levels of Hg, Se, and Zn in the captive breeding center. In addition, concentrations of As, Co, Cr, and Ni were significantly greater in the sediments of three types of foraging habitats for wild crested ibis, but concentration of Se was greater in the soil of captive cages. Feather and eggshell of crested ibis exhibited a very consistent indication for most of the trace elements, and concentrations of almost all of the elements in the excrements were very consistent with the results in the environmental samples (sediments or soils). Concentrations of As, Hg, Mn, and Zn in feathers, and Mn and Zn in eggshells of wild and captive crested ibis were greater than those in other similar species. Moreover, As, Cd, Cu, and Mn concentrations in excrement of wild crested ibises were greater than that in captive individuals and other species, but Se and Zn concentrations in excrement of captive crested ibises were greater than that of the wild and other species. The present study provided evidence that both of the wild and captive crested ibis were exposed to trace elements, which may be harmful to their health.

How much can we trust GPS wildlife tracking? An assessment in semi-free-ranging Crested Ibis Nipponia nippon

GPS tracking has been increasingly used for wildlife studies in recent decades, but its performance has not been fully assessed, especially for newly developed lightweight transmitters. We assessed the performance of eight GPS transmitters developed in China by attaching them to Crested Ibises Nipponia nippon confined to two acclimation cages mimicking real habitats. We calculated the distance between GPS locations and the centroid of the cages as the positioning error, and used the 95% (95th percentile) positioning errors to define the accuracy. The positioning success averaged 92.0%, which is much higher than that of previous studies. Locations were not evenly distributed by Location Class (LC), with the LC A and B locations accounting for 88.7%. The observed 95% positioning error in the locations of LC A (9-39 m) and B (11-41 m) was quite accurate, while up to 6.9-8.8% of poor-quality locations were detected in LC C and D with >100 m or even >1, 000 m positioning error. Positioning success and accuracy were different between the test sites, probably due to the difference in vegetation structure. Thus, we argue that the tested transmitters could provide a large proportion of high-quality data for fine-scale studies, and a number of poor-quality locations that need attention. We suggest that the HPOD (horizontal dilution of precision) or PDOP (positional dilution of precision) be reported instead of the LC as a measurement of location accuracy for each location to ensure identification and filtering of implausible locations.

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

Traditional agriculture benefits a rich diversity of plants and animals. The winter-flooded rice fields in the Qinling Mountains, China, are the last refuge for the endangered Asian crested ibis (Nipponia nippon), and intensive efforts have been made to protect this anthropogenic habitat. Analyses of multi-temporal satellite data indicate that winter-flooded rice fields have been continuously reduced across the current range of crested ibis during the past two decades. The rate of loss of these fields in the core-protected areas has unexpectedly increased to a higher level than that in non-protected areas in the past decade. The best fit (R (2) = 0.87) numerical response model of the crested ibis population shows that a reduction of winter-flooded rice fields decreases population growth and predicts that the population growth will be constrained by the decline of traditional winter-flooded rice fields in the coming decades. Our findings suggest that the decline of traditional rice farming is likely to continue to pose a threat to the long-term survival and recovery of the crested ibis population in China.

Genomic characterisation of two virulent Newcastle disease viruses isolated from crested ibis (Nipponia nippon) in China

This paper describes the complete genomic sequences of two virulent Newcastle disease virus (NDV) isolates, Shaanxi06 (prevalent genotype VIId) and Shaanxi10 (novel sub-genotype VIi), from sick crested ibises. The genomes of both isolates were 15,192 nt long and consisted of six genes in the order of 3'-NP-P-M-F-HN-L-5'. The genomes of the two isolates were highly similar to other reference NDV strains. However, some unique features were found in the HN protein of Shaanxi06 and the F gene end of Shaanxi10. Shaanxi06 and Shaanxi10 shared the same virulent motif (112-)R-R-Q-K-R-F(-117) at the F protein cleavage site, which coincided with previous pathogenicity test results. Phylogenetic analysis revealed that both isolates were clustered within class II NDV, with Shaanxi06 in genotype VII and Shaanxi10 in genotype VI. Both isolates shared high homology with the prevalent genotype NDV strains that circulate in fowls and waterfowls. This study is the first to provide genomic information about a novel sub-genotype VIi NDV strain and another genotype VIId virus, which will be useful for subsequent investigations.