External limitations
Application of the MIREN road survey protocol might be hindered in some
regions, most obviously due to the lack of roads spanning sufficiently
large elevation gradients. Additionally, local land ownership, safety
issues or administrative complexities may complicate establishment and
monitoring, for example on private land or in protected areas (Figure
5). Such issues might be of particular relevance in the MIREN survey
design, as MIREN strives to cover a large elevation gradient spanning
multiple vegetation zones. At the same time, the proximity of survey
plots to roads increases the risk of damage over time (e.g. through road
widening, mowing, pesticide use, expanding urbanization or occasional
vandalism). The simplicity of the plot set-up nevertheless greatly
reduces the impact of such damage or vandalism in the long term.
Long-term monitoring itself comes at a risk of funding insecurities, as
the timeframe of 5-year intervals is beyond what is covered by most
grants. Even though maintaining the observational sites themselves comes
at virtually no financial cost, the monitoring involves considerable
input of field labour, for which costs will vary between regions (Figure
5).