Geodiversity in northern high latitude and altitude areas – spatial patterns and key drivers

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Title: Geodiversity in northern high latitude and altitude areas – spatial patterns and key drivers
Author: Johanson, Jorunn
Other contributor: Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta
University of Helsinki, Faculty of Science
Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten
Publisher: Helsingin yliopisto
Date: 2021
Language: eng
Thesis level: master's thesis
Degree program: Maantieteen maisteriohjelma
Master's Programme in Geography
Magisterprogrammet i geografi
Specialisation: Luonnonmaantiede
Physical Geography
Abstract: Geodiversity, the natural abiotic variety of the Earth’s surface, is an essential part of natural diversity and plays an important role in providing the abiotic ecosystem services that all life depends on. Geodiversity is increasingly threatened by human activities and climate change, and consequently there is a growing importance of including geodiversity in decision-making. However, there is still a lack of studies assessing the spatial variation and key drivers of geodiversity, especially in high latitude and altitude areas, and this study, therefore, aims to contribute to an improved understanding. In this study, the geodiversity of a subarctic mountainous area in Northern Norway was mapped using remotely sensed data and applying a grid-based approach. The spatial variation of geodiversity was assessed using five different measures, and the relationships between geodiversity and several topographical parameters were analysed using correlation analysis (Spearman’s rank correlation, RS) as well as both univariate and multivariate linear regression. The vertical variation of geodiversity was also examined to analyse the variation of geodiversity along altitudinal gradients. A total of 54 geodiversity elements were observed in the study area and the number of elements per grid cell varied from 7 to 36. Four of the geodiversity measures correlated strongly, resulting in relatively similar spatial patterns of diversity. Higher values tended to follow the valley systems and cluster in the vicinity of rivers and larger streams. Topographically diverse grid cells, containing both steeper slopes and smoother areas, also contained a higher diversity. Low diversity occurred mainly on the highest elevations as well as on the steepest slopes. The majority of the univariate relationships between the measures of geodiversity and the topographical parameters were statistically significant, although the correlations generally were relatively weak. The regression models further confirmed the relationship between topography and geodiversity, and revealed various statistically significant relationships, as well as the presence of both linear and unimodal relationships. Higher geodiversity generally occurred in topographically heterogeneous landscapes, as well as in the vicinity of rivers and larger streams, where both erosion and accumulation processes are prominent, leading to a great variety of geomorphological elements and soil deposits. The summits and slopes of the mountain massifs, on the other hand, displayed a lower geodiversity. In these areas, erosion is significant, but accumulation processes are lacking. Furthermore, the hydrological diversity is generally low there. The vertical patterns of geodiversity were related to the spatial patterns since total geodiversity decreased steadily as mean elevation rose above 600 m a.s.l. The influence of topography on geodiversity patterns could also be seen in the statistically significant relationships between several topographical parameters and the geodiversity measures. There was, however, some variation in the strength of the correlations, and the weaker relationships can partly be explained by the contradictory effect of slope angle and elevation on geodiversity. These patterns were further confirmed by the fact that the regression models revealed not only linear, but also unimodal relationships between the topographical parameters and geodiversity. Although topography seems to have an important effect on all geodiversity measures, there is some variation in which topographic parameters are the most important for the different measures. To conclude, this study of a northern high latitude mountainous area shows that high geodiversity occurs in the vicinity of rivers and larger streams, as well as in landscapes with a varied relief. Topography has a statistically significant influence on geodiversity, although the magnitude and direction of the effect varies between the elements of geodiversity. To facilitate the incorporation of geodiversity in education, land use planning, resource management and nature conservation, more research is still required about the patterns and drivers of geodiversity.
Subject: geodiversity assessment
geodiversity index
natural diversity
abiotic nature
regression modelling

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