Species coexistence is a mysterious and attracting phenomenon in nature. How different species interact and cope with future environmental change together remains uncertain. Answering this key question is particularly important for alpine ecosystems and species that are severely threatened by human-driven climate change and land use change and their interactions, as the available habitat area gets smaller as the elevation goes up, combined with the unique outcome of high-alpine species’ adaptation to extreme conditions. What’s more urgent is that to find a better and timely solution for biodiversity conservation by making full use of ecological keystone species (which is often regarded as the umbrella species in conservation practices) in ecosystems in the Anthropocene.
So, it’s easy for us to think of and care about the Qinghai-Tibet Plateau (QTP) and the species living there and their intertwined fates under this circumstance. Unlike other mountain and plateau systems, the QTP covers a vast area with an average elevation of more than 4,500 meters, providing us with unique species groups to carry out such a study. Three burrow-sharing species which interact tightly in the alpine ecosystem are used in our study: one burrow-digging mammal, the plateau pika (Ochotona curzoniae), which is the keystone and umbrella species in the QTP, and two burrow-using birds, the white-rumped snowfinch (Onychostruthus taczanowskii) and the red-necked snowfinch (Pyrgilauda ruficollis). More specifically, plateau pikas create burrows, while snowfinches use burrows. Fascinatingly, this natural phenomenon was recorded a long time ago, dating back to the early 3rd century BC in ancient Chinese book “The Classic Mountains and Seas”. What an amazing study system!
After a heavy snowfall, a white-rumped snowfinch jumped from pika’s burrow to the ground and subsequently, a plateau pika slowly poked its head out of the hole. Credit: Zhao Chao
Our group (Lei’s and Qu’s lab) have been working on the two snowfinches for over 20 years and thanks to all the early field and lab works I had the change to carry out this research successfully. Of course, working only on ourselves is far from enough. Luckily, we’ve got company with the mammal group (Yang’s and Ge’s lab) and their abundant knowledge about small mammals. At that point, two clear questions were: (1) how would they respond to future global change? And, (2) with high possibility, would umbrella species has similar population-level vulnerability with its beneficiary species?
To answer these questions, we generated re-sequencing data for three species and collected climate, land use, and a suite of landscape data from current to future predicted scenarios. After all datasets were set, we built a research framework that considered local adaptation, range shift, dispersal, and population connectivity together to tackle the two scientific questions. In short, we found populations inhabiting in different ranges of the QTP hold distinct capacities to survive in the future due to the obvious signal of local adaptation and the existence of landscape barrier. This part helped us to determine the most vulnerable and stable ranges and populations, good for conservation, but not enough. What concerned us more was the patterns of vulnerability between species and hence the potential persistence of plateau pika as the umbrella species in a long time. Results showed that pika and snowfinch had similar patterns of vulnerability in any case, especially in the aspect of range shift, suggesting that the umbrella species, at least in our study system, can effectively mirror the risks the species which coevolve with it.
Umbrella species is a classic and important concept in ecology and conservation biology, but it’s argued constantly whether this concept is still useful in the face of future environmental change and, even more stringently, whether we should use it anymore? Our findings delightedly suggest that if we want to keep pace with today’s rapidly changing environment and perform fast and effective conservation management at the same time, it’s reasonable to identify and utilize umbrella species in practices, but be cautious in the meantime. In the context of the Anthropocene, we truly hope that understanding the importance of umbrella species could help us move forward in biodiversity conservation before it is too late.