Climate change and other global change drivers threaten plant diversity
in mountains worldwide. A widely documented response to such
environmental modifications is for plant species to change their
elevational ranges. Range shifts are often idiosyncratic and difficult
to generalize, partly due to variation in sampling methods. There is
thus a need for a standardized monitoring strategy that can be applied
across mountain regions to assess distribution changes and community
turnover of native and non-native plant species over space and time.
Here, we present a conceptually intuitive and standardized protocol
developed by the Mountain Invasion Research Network (MIREN) to
systematically quantify global patterns of native and non-native species
distributions along elevation gradients and shifts arising from
interactive effects of climate change and human disturbance. Usually
repeated every five years, surveys consist of 20 sample sites located at
equal elevation increments along three replicate roads per sampling
region. At each site, three plots extend from the side of a mountain
road into surrounding natural vegetation. The protocol has been
successfully used in 18 regions worldwide from 2007 to present. Analyses
of one point in time already generated some salient results, and
revealed region-specific elevational patterns of native plant species
richness, but a globally consistent elevational decline in non-native
species richness. Non-native plants were also more abundant directly
adjacent to road edges, suggesting that disturbed roadsides serve as a
vector for invasions into mountains. From the upcoming analyses of time
series even more exciting results especially about range shifts can be
expected. Implementing the protocol in more mountain regions globally
would help to generate a more complete picture of how global change
alters species distributions. This would inform conservation policy in
mountain ecosystems, where some conservation policies remain poorly
implemented.
Think globally, measure locally: The MIREN standardized protocol for monitoring species distributions along elevation gradients