Linking small-scale topography with microclimate, plant species diversity and intra-specific trait variation in an alpine landscape

Abstract

Background: Small-scale topographic complexity is a characteristic feature of alpine landscapes, with important effects on alpine plant distribution. Aims: We investigated the links between small-scale topographic complexity and resultant microclimatic heterogeneity, vascular-plant species richness and beta diversity, and realised niche width and trait variation of some target species. Methods: We recorded temperature and soil moisture within 10 sites (40 m × 40 m) of differing topographic complexity in alpine terrain at Finse, Norway (N 60°36ʹ, E 7°33ʹ). Plant species occurrence and traits of target species were recorded in 16 sample plots at each site. Results: Sites differed significantly in microclimatic heterogeneity, and topographically rough sites were always more heterogeneous than flatter ones. Greater species richness and turnover was associated with greater microclimatic heterogeneity, and rough sites contained 15-55% more species than flatter ones. Plant species had on average wider realised niches when growing at rough sites. Individuals of Bistorta vivipara, but not those of Luzula spicata, tended to exhibit greater phenotypic variation at rough sites. Conclusions: Rough alpine terrains create small-scale variation in microclimate, promoting species richness and beta diversity. In the event of climate change, small-scale microclimatic heterogeneity might allow plant species to escape from regional climate change by short-distance migration to local micro-refugia. This study suggests that the opportunity for such responses would be greater in topographically complex terrains.

Alpine timberline population dynamics under climate change: a comparison between Qilian juniper and Qinghai spruce tree species in the middle Qilian Mountains of northeast Tibetan Plateau

“…Differences in slope aspects, slope position and other topographical conditions may cause differences in topography-related microclimatic conditions (e.g. temperature, rainfall and relative humidity; Geiger et al 1965;Opedal et al 2015). Seedling germination, sapling mortality and tree growth can all vary with microclimatic conditions, leading to variations in the recruitment patterns of the same tree species (Jaganathan & Liu 2014).…”

Incorporating microclimate into species distribution models

“…For example, in mountain regions with heterogeneous topography, microclimate can vary noticeably over short distances due to a steep elevational gradient and rugged terrain (Gottfried et al 1999, Holden et al 2011, Sears et al 2011, Opedal et al 2015, Graae et al 2018. Annual average temperatures have been found to vary up to 6°C within spatial units of 1 km² in northern Europe (Lenoir et al 2013).…”

“…arctic-alpine, forest, urban), fine resolution climate data is needed (Illan et al 2010, Scherrer and Körner 2011, Suggitt et al 2011, Graae et al 2012, Opedal et al 2015. arctic-alpine, forest, urban), fine resolution climate data is needed (Illan et al 2010, Scherrer and Körner 2011, Suggitt et al 2011, Graae et al 2012, Opedal et al 2015.…”

Ultra-Fine Scale Spatially-Integrated Mapping of Habitat and Occupancy Using Structure-From-Motion

“…While most gradient analysis studies focus on the landscape scale, important fine scale details can be lost when data are collected at such large scales [13] as small scale heterogeneity in the landscape has been shown to promote species richness and beta diversity in plant communities [14]. In addition to information lost due to inappropriate scale, ecological datasets almost always project a three-dimensional landscape onto a two-dimensional raster, preventing a complete consideration of covariates that require a three-dimensional understanding of habitat (e.g., terrain, canopy structure, etc.)…”

“…In addition to information lost due to inappropriate scale, ecological datasets almost always project a three-dimensional landscape onto a two-dimensional raster, preventing a complete consideration of covariates that require a three-dimensional understanding of habitat (e.g., terrain, canopy structure, etc.) [14]. The additional information provided by digital elevation models (DEMs) can often be used as proxies for environmental condition and permit direct modeling of many processes, such as hydrological flow, critical to a site's suitability.…”