Influence of soil and elevation on roadside cryptogam diversity in the tropical Andes

Background: The deforestation caused by road construction is one of the main drivers for both biodiversity and function loss in tropical ecosystems. Terricolous cryptogams are pioneers in colonizing roadside and they are limited by environmental and edaphic factors, thus, cryptogams may act as pioneers for ecosystem rehabilitation at roadside.Methods: This research was aimed at determining the diversity and composition of terricolous cryptogams, as well as their relationship with elevation and soil properties among roadside of the tropical Andes of Ecuador, in order to establish indicator species of this anthropized ecosystems. Five elevations were selected and in each one 50 grids of 20 cm x 30 cm were sampled (250 in total along the road), where occurrence, cover and identification of every cryptogam species were recorded. To evaluate the effect of elevation and soil properties on cryptogam richness, a linear model was conducted. Species composition among elevations was compared by non-metric multidimensional scaling (NMDS), and their relationship with the environmental variables through a correla-tion with adjusted axes was performed. A total of 72 species were recorded, those being 44 bryophytes and 28 lichens. Species richness and composition of terricolous cryptogams were influenced by elevation and soil properties, thus the richness is higher at elevations E1, E2 and E3 (2600, 2200 and 1800 m a.s.l.), differing from low elevations E4 and E5 (1400 and 1000 m a.s.l.). Higher elevations with specific soil conditions (e.g bulk density, nitrogen and silt) harbored different cryptogam communities than those in lower elevations.Conclusions: A combination of both elevation and soil properties are shaping the colonization by terricolous cryptogams commnunities. As such, 18 species were identified as the best indicators for all sets of environmental conditions at the roadside, which can therefore be considered for monitoring ecological processes in tropical areas. Use of biocrusts for restoration is an emerging field. If implemented in the study region, elevation and soil drivers may help to better chose the more suitable cryptogam species to manage and stabilize roadside in tropical roads.