Topography-based metrics for climate-change microrefugia: topodiversity, glaciers, wetlands, cool slopes in British Columbia (Version 2)

Suggested citation: Kehm, G. 2026. Topography-based metrics for climate-change microrefugia: topodiversity, glaciers, wetlands, cool slopes in British Columbia (Version 2.0). Place of publication: GKA Geographic Solutions Inc., Vancouver, BC. doi: 10.5281/zenodo.18990506 Map example images: A) Macro Land Forms of British Columbia map B) Topodiversity of British Columbia map Summary: The physical landscape plays a significant role in determining where biodiversity can exist, with its influence over the distribution of habitat types. The heterogeneity in physical combinations of land form, slope, soils, hydrology, geology and altitude results in a diversity of climates such that species can make smaller spatial adjustments to track suitable habitat and climatic conditions (Laurence et al., 2021); Carroll et al., 2017; Littlefield et al., 2017). While physical diversity focuses on the non-living aspects of the Earth, it is closely linked to biodiversity, as the abiotic foundation plays a key role in the distribution and survival of species. Due to the slow, enduring qualities of the physical landscape containing high physical diversity, conserving large areas of high physical diversity can maintain the future persistence of suitable climatic conditions for species survival (Hannah et al., 2007; Loarie et al., 2009). Physical environmental diversity includes both topodiversity and geodiversity. Both terms are often used interchangeably and describe different combinations of physical features with implications for biodiversity conservation. Geodiversity, also referred to as enduring features, encompasses the natural range of geological, geomorphological, landform, pedological (soils), and hydrological features and processes. This is an inclusive term capturing a matrix of attributes in the landscape that support biodiversity, broadly covering ecologically meaningful groupings of geology, landform, and altitude. Geodiversity examples include ‘mid-elevation toe slope on calcareous bedrock’ or ‘low elevation dry flats on thick glacial fluvial sediment’. Geodiversity is useful as an input into processes for identifying new conservation lands, assessing the representative biodiversity contributions of existing conservation lands, and stratifying field sampling designs. Topodiversity is the variety and abundance of landforms and terrain, including hydrological complexes like wetlands, lakes, rivers and streams. Landform examples include islands, north-facing sideslopes, toe slopes, cliffs and ridge lines. Topodiversity metrics are useful in identifying climate-change microrefugia for conservation planning and management. Topographic diversity is highly correlated with reduced climate change impacts in protected areas worldwide (Lawrence, A. 2021). The conservation of some ecologically important taxa, such as bee pollinators, may be aided in site prioritization using topodiversity metrics (Doherty, K. 2021). A topodiversity (and geodiversity) analysis, supported by climate change refugial characteristics of cool, landform types, will help increase the resilience of conservation planning actions over time. Additional benefits of applying topodiversity analyses include: --Helping to inform decisions and management of resource development projects in ‘special management areas’ by supporting precautionary principles of minimizing environmental impacts.--Additional information for input into spatial analyses identifying important priority areas in land use or watershed-based planning processes.--Provide additional leverage for decision makers when arguing against land conversion/extractive processes in specific areas.This dataset applies the Gini-Simpson diversity using the Fragstats function in the QGIS application (Serena Pallecchi, re. McGarigal, K., and B. J. Marks). This is the oldest and simplest method to measure biodiversity. It is relatively less sensitive to richness and thus rare patch types, as it highlights relative species abundance. Versioning: Version 1.0 of the topodiversity index was based on a Gini-Simpson Diversity Index (GSDI) approach. Shannon’s Diversity Index (SHDI) was applied in this revision as it is better at highlighting rarity. Approach: Fragstats V4.3 (K. McGarigal 2023) software was used with the following analysis parameters: a) 8-cell neighbourhood rule b) Sampling strategy Moving Window without kernel weighting (8-cell, square shape with side length of 350m). Values range from -1.73 to 2.19 (highest diversity). c) Moving window search radii: Several Fragstat SHDI search radii were run and qualitatively evaluated using the following distances (meters): 200, 300, 350, 400, 1000. A 350m search radius distance appears to best capture the extent of diverse and adjacent macro land forms at the scale of the province without exaggerating representation (both under or over) of high topodiversity areas based on macro land forms, and maintaining connectivity between high diversity areas (i.e. along a lateral moraine). The size of your study area and your project goals will influence which diversity index to use and the parameter values to run it. Processing for the SHDI: ArcGIS Desktop Pro software symbolizes the SHDI with four classes using an Equal Interval Classification to capture the two highest diversity classes, tightening the location. Excluded two values -999 and 0. SHDI four-class ranges: Lowest diversity class 1: -1.729039009- -0.747473102 Low diversity class 2: -0.747473102 – 0.234092804 Higher diversity class 3: 0.234092804 – 1.215658711 Highest diversity class 4: 1.215658712 – 2.197224617 A four-class geometrical interval classification system is used to display the range of data from lower to higher topodiversity. The original input macro land form data set is available to download as a Map Layer Package or a Geotiff file here: https://zenodo.org/records/15685110 Cooler macro land forms are available as a reclass from the dataset above and provide a mask to focus on potential high, cool, physically diverse places. The map packages (instead of GeoTIFF files) contain complete legend styling.