Think globally, measure locally: The MIREN standardized protocol for monitoring species distributions along elevation gradients

Abstract

Climate change and other global change drivers threaten plant diversity\nin mountains worldwide. A widely documented response to such\nenvironmental modifications is for plant species to change their\nelevational ranges. Range shifts are often idiosyncratic and difficult\nto generalize, partly due to variation in sampling methods. There is\nthus a need for a standardized monitoring strategy that can be applied\nacross mountain regions to assess distribution changes and community\nturnover of native and non-native plant species over space and time.\nHere, we present a conceptually intuitive and standardized protocol\ndeveloped by the Mountain Invasion Research Network (MIREN) to\nsystematically quantify global patterns of native and non-native species\ndistributions along elevation gradients and shifts arising from\ninteractive effects of climate change and human disturbance. Usually\nrepeated every five years, surveys consist of 20 sample sites located at\nequal elevation increments along three replicate roads per sampling\nregion. At each site, three plots extend from the side of a mountain\nroad into surrounding natural vegetation. The protocol has been\nsuccessfully used in 18 regions worldwide from 2007 to present. Analyses\nof one point in time already generated some salient results, and\nrevealed region-specific elevational patterns of native plant species\nrichness, but a globally consistent elevational decline in non-native\nspecies richness. Non-native plants were also more abundant directly\nadjacent to road edges, suggesting that disturbed roadsides serve as a\nvector for invasions into mountains. From the upcoming analyses of time\nseries even more exciting results especially about range shifts can be\nexpected. Implementing the protocol in more mountain regions globally\nwould help to generate a more complete picture of how global change\nalters species distributions. This would inform conservation policy in\nmountain ecosystems, where some conservation policies remain poorly\nimplemented.