Comparative analysis of trophic niche using stable isotopes provides insight into resource use of giant pandas

Trophic niche is the result of the long-term evolution of species and can reflect the pressures they experience in habitats. The whole-genome sequencing of giant pandas (Ailuropoda melanoleuca) has indicated that populations distributed in Qinling (QIN) and non-QIN probably diverged 300 ky ago. Although many studies regarding foraging strategy, habitat preference, and niche partition have been conducted on these populations, there is still a lack of precise quantification of trophic niches. Here, we calculated and compared isotopic trophic niche widths of giant pandas from Sichuan (SC) and QIN populations by measuring carbon and nitrogen isotopes of their hairs; combined with data from sympatric mammals, we explored the relative trophic positions of giant pandas in the ecosystem, respectively. The Stable Isotope Bayesian Ellipses in R (SIBER) model results showed the trophic niche width of QIN pandas was 3.44‰2, which was significantly bigger than those of the SC population (2.03‰2), with an overlapping about 1.45‰2; and they both occupied a unique position in the context, almost one trophic level lower than herbivores. Then, we determined the isotopic ratios of the main foods from the habitats of these pandas; the results suggested that the isotopic difference between bamboo shoots and other parts plus the various feeding selections of pandas on them accounted for pandas' trophic niche widths. We considered the higher nutrition availability and digestible food resources giving QIN pandas a wider trophic niche than pandas from SC. This conclusion provides a new insight into the resource use and trophic ecology of giant pandas and is important to develop refined management plans for the two populations.

A review of research advances and perspectives on the habitat ecology of Sichuan and golden takins: 2001 to 2022

The Sichuan takin (Budorcas tibetanus) and the golden takin (Budorcas bedfordi) are endemic to China. Studies of their habitat ecology have attracted attention, but dedicated reviews of the topic have not been published. To fill this gap, research advances on the habitat ecology of these takin species were reviewed based on published journal papers from 2001-2022, covering habitat selection and use, as well as habitat assessment and protection. Habitat selection and use by the takins received the most frequent reports in a few protected areas, such as the Tangjiahe Nature Reserve in Sichuan and the Foping Nature Reserve in Shaanxi. Higher herb cover characterized some of the Sichuan takin habitats, while some of the golden takin population exhibited seasonal altitude migration. The focus on habitat assessment and protection differed between the two species. Studying the habitat of the Sichuan takin involves the relationship between its habitat and the protected areas and habitat status in various ranges while studying the habitat of the golden takin involves habitat distribution and change, protection effects, and corridor planning. Some issues worthy of consideration in future research are proposed, including basic habitat information, impacts of human disturbances, habitat restoration, and theoretical, independent, and comprehensive studies on both takins. Habitat conservation frameworks should be formulated for both takins to improve protection and restoration effects. This review provides convenient information to help understand the habitat characteristics of the two takins and is a reference for future research.

Integrating Livestock Grazing and Sympatric Takin to Evaluate the Habitat Suitability of Giant Panda in the Wanglang Nature Reserve

Simple Summary

Giant pandas are facing the threat of habitat degradation. Both grazing livestock and sympatric animals have certain impacts on the giant panda habitat. This study evaluated the habitat suitability of giant panda in Wanglang Nature Reserve by simultaneously investigating livestock grazing and sympatric takin. Results for the giant panda habitat in Wanglang are not optimistic, and the extensive overlap of suitable habitats for livestock, takin and panda makes the situation worse.

Abstract

Habitat suitability provides essential information for the management of protected species. However, studies that jointly consider the impacts of human disturbance and sympatric animals in habitat suitability assessments of giant panda are limited, which may overestimate the habitat status. To address this issue, we evaluated the habitat suitability of giant panda in Wanglang Nature Reserve by simultaneously investigating livestock grazing and sympatric takin via MAXENT, a new attempt at the assessment of the habitat suitability of giant panda. We focused on describing the habitat suitability of giant panda and determining the habitat overlap between livestock, takin, and panda to evaluate the impacts of livestock grazing and sympatric takin on the suitable giant panda habitat. Results revealed that only 16.33% of the area in Wanglang was suitable giant panda habitat, of which 67.66% was shared by livestock, and 97.99% of the remaining suitable panda habitat not shared by livestock was revealed to be shared by takin. The results indicate an unfavorable habitat status of giant panda in Wanglang, with the potential extensive habitat overlap between livestock, takin and panda exerting further pressure. Thus, to effectively protect giant pandas and their habitats, grazing activity should be controlled. Furthermore, to accurately protect sympatric animals, the monitoring of panda and takin activities in the overlapping areas must be maintained.

Evaluating giant panda as a surrogate species for conservation co-occurring species in the Baishuijiang National Nature Reserve

The establishment of nature reserves is a key approach for biodiversity conservation worldwide. However, the effectiveness of nature reserves established by protecting the habitat needs of surrogate species is questioned. In this study, the Baishuijiang National Nature Reserve (Baishuijiang NNR), located in the Minshan Mountains, China, which is established mainly for the conservation of giant panda (a surrogate for the conservation of other endangered species) was selected. We quantitatively evaluated the conservation effectiveness of the reserve for giant panda and co-occurring species (here, seven protected species) using a maximum entropy model (Maxent), and analyzed spatial congruence between giant panda and other seven species. Results shown that the habitat of giant panda generally included the habitat of other seven protected species, suggesting that conservation of giant panda habitat also allows the conservation for the habitat of almost co-occurring species. Hence, the natural reserve established for giant panda as a surrogate species has a relatively high effectiveness. A high proportion of the suitable habitat for six species is inside the core zone, but a high proportion of the suitable habitat for two species is located in the experimental and buffer zones. Thus, the two species are affected by human activities. To improve the conservation effectiveness of the nature reserve, the management zones need to be amended. The result of the study will be beneficial for future conservation and management of the reserve. This study provides an effective method for evaluating the conservation effectiveness of nature reserves in other area of the worldwide.