As both native and exotic species shift their distributions in response to climate change and through biological invasions, many expand their ranges across elevational gradients. This expansion results in the reassembly of ecological communities, mediating the effects of climate warming on biodiversity and key ecosystem functions. RangeX is a multidisciplinary, replicated field and laboratory experiment being conducted in climatically and socio-ecologically contrasting regions (Switzerland, Norway, China, South Africa) that seeks to better understand these range shifts in mountain systems. By investigating novel biotic interactions both above and below ground across multiple elevations, we aim to: (i) disentangle the drivers of range expansions; (ii) uncover the ecological consequences of range-expanding species; (iii) predict the extent and impacts of future range expansions; (iv) develop policy recommendations related to range-expanding species in montane environments.



What processes explain variation in species’ range expansion with climate warming?

OBJECTIVE:  Develop an explanatory framework for the processes driving variation in species’ range expansion with climate warming.

HYPOTHESIS:  Variation in elevational range expansion is explained by regional variation in climate warming velocity, co-limitation by other abiotic factors (e.g. soil fertility, moisture availability), and the strength of negative and positive interactions with above- and below-ground biota.


How do range-expanding species impact biodiversity and key ecosystem functions, and how will these impacts feed back to changing climate?

OBJECTIVE: Quantify the contribution of range-expanding plants to change in biodiversity, ecosystem processes (e.g. carbon cycling and pollination services), and possible climate feedbacks, in mountain ecosystems globally.

HYPOTHESIS: Range-expanding plants reduce the diversity of resident species through competitive exclusion, and change ecosystem functioning by altering plant community interactions with above- and below-ground organisms. Specifically, lowland plant species, whether native or non-native, will compete with resident species for resources and pollinators, and will increase rates of litter decomposition and C turnover in soils, causing a positive feedback to climate warming.




Can we predict which species are most/least able to expand their ranges with climate warming, and their impact on ecosystem processes?

OBJECTIVE:  Develop trait-based predictors of range expansion (identifying potential “winners”) and range-expander impact on native biodiversity (potential “losers”) and ecosystem processes.

HYPOTHESIS: Successful range-expanding species possess traits related to high biomass productivity, fast resource acquisition and nutrient cycling, high dispersal potential and competitive ability. This introduction of novel traits through range expansions predicts impacts on biodiversity (e.g. loss of species lacking such competitive ability and fast resource cycling traits) and ecosystem processes below-ground (e.g. traits related to resource dynamics predicts changed C cycling) and above-ground (e.g. floral traits predict disruption of pollinator services).


Can better ecological understanding of range expansions be synthesised with stakeholder knowledge to improve policy and management of range expansions and biodiversity?

OBJECTIVE: Co-develop policy recommendations related to range-expanding species under climate change, with a focus on mountain ecosystems.

HYPOTHESIS: Science-stakeholder co-development of knowledge and international collaboration can identify barriers and opportunities, thus contributing to improved policy and management from regional to global scales.

Sheep friends, high site
Fig 1

RangeX links processes underlying species’ climate warming-driven range expansions (WP1) to their impacts on biodiversity and ecosystem functioning above- and below-ground (WP2). Using distributed experiments, comparative studies and analyses of existing data on range-expanding species, we will develop predictors for “winners” and “losers”, and their associated impacts on ecosystem functioning (WP3). We will work closely with stakeholders, at local to global scales, to co-develop understanding to support knowledge- based management and policy regarding species’ range expansions under climate change (WP4).