Opportunities
Many drivers of global change act rapidly and interactively, and
intensify over time, so assessing their impact on global biodiversity
urgently requires comparable data collected on a truly global scale. The
MIREN road survey protocol has already demonstrated its potential to
explain crucial patterns in native and non-native species
redistributions along mountain roads, but there are a range of further
applications that can be explored. For example, due to its simplicity
the protocol can readily be implemented in many more mountain ranges and
regions. Increasing the number of participating regions, all with their
unique combination of climatic conditions and anthropogenic pressures,
would further increase the potential to draw general conclusions about
the interacting effects of climate change and roads as anthropogenic
disturbance on mountain plant communities (Guo et al., 2018). This is
particularly important for regions currently under-represented by the
existing MIREN survey sites (Figure 4), such as Africa, Eastern Asia and
central America, regions for which long-term biodiversity data are often
lacking (Maestre & Eisenhauer, 2019). Despite these spatial gaps, MIREN
has already more than doubled in size on its road to becoming a
global-scale network since it was first established in eight regions.
New participants would thus be able to place their region into a much
larger spatio-temporal picture and, as time passes, get an increasingly
strong grasp of how species distributions are changing dynamically,
regionally and across the world.
With its potential to answer important local questions, and feed into
the growing multi-region database, we hope that the MIREN road survey
protocol will become the protocol of choice for those interested in
native and non-native plant biodiversity dynamics in mountain regions.
At the local scale, it can provide good baseline data on biodiversity
changes along elevation gradients in disturbed regions, with
opportunities to inform management decisions (McDougall et al., 2011a).
For example, it can inform policy makers on some of the impacts of urban
expansion and new infrastructure projects in mountains, as well as
identify new non-native species before they become problematic. The
protocol can also provide essential biodiversity variables for global
monitoring efforts (Jetz et al., 2019), since it provides insight into
species abundance change over space and time and can further enrich the
mountain biodiversity data provided on the online data portal of the
Global Mountain Biodiversity Assessment (GMBA). In doing so, it has the
capacity to inform global biodiversity policy initiatives, such as the
Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem
Services (IPBES).
Further opportunities include add-ons and expansions to the protocol
design, for example to measure microclimate (Lembrechts et al., 2019),
dispersal dynamics (e.g. with seed traps), soil biodiversity (e.g.
analyses of the soil microbiome or mycorrhizal colonization of roots) or
plant-animal interactions (e.g. pollinator records, herbivore
abundance). Collecting such data would be important not only in
isolation, but also for helping to create explicit links between
descriptive and predictive species distribution models, both at local
and global scales. Such efforts could even facilitate modelling of
(changes in) the distributions and habitat occupation of mountain plant
species, for instance by coupling georeferenced long-term survey plots
with high-resolution remotely sensed and modelled environmental data
(Randin et al., 2020). The survey approach can similarly be expanded by
adapting it for use along other linear introduction pathways for
non-native species, such as rivers or hiking trails, or by connecting it
with other standardized global biodiversity surveys and assessments,
such as GLORIA (Pauli et al., 2015), sPlot (Bruelheide et al., 2019),
the Global Inventory of Floras and Traits (GIFT; Weigelt et al., 2020),
the Global Naturalized Alien Flora (GloNAF) database (van Kleunen et
al., 2015) and the BioTIME database (Dornelas et al., 2018). Finally,
the protocol has already shown to have great potential for teaching, for
instance by training undergraduate and graduate students in vegetation
sampling, while also having relevance for local policy and management,
for example as demonstration sites (Figure 5).