Quiñónez, AL, Fuller, TK and Randhir, TO. (2018). A Review of Otter Distribution Modeling: Approach, Scale, and Metrics. IUCN Otter Spec. Group Bull. 35 (2): 97 - 127
APPENDIX A3 – METRICS USED AT EACH SCALE
Table A9 - Metrics used at the local scale.
Metrics in bold where found to be significant at this scale. Many studies do not consider variable significance in their analysis.
| Classification | Variables | Metrics |
| Disturbance variables | Roads | distance to roads, number of major roads, park roads and paved roads crossing the watershed, number of dirt roads crossing the watershed, roads, total highway and roads density, range distance to road |
| Population | distance to towns, total number of human residences within 500 m of the watershed occupied year-round, total number of homes within 500 m of the watershed occupied on a seasonal basis, settlement density, human settlements | |
| Tourism | number of visitors | |
| Contaminates | suspended solids, nitrates, phosphates, coliforms, dissolved oxygen | |
| Land use | grazing area, crops, land use, floodplain area (%), protected area (%), urban use | |
| Others | total number of times a footpath(s) crossed the stream, total length of footpath(s) within 25 m of the watershed, boat traffic (2), impact(human), polder cover (%) | |
| Climate variables | Temperature | temperature |
| Precipitation | precipitation | |
| Terrestrial variables | Vegetation variables | vegetation type of stream bank zone, vegetation type, vegetation complexity, plant cover(%), riverbank vegetation (types), forest, tree cover(%), forestry(%), % of forested land area within 100 m of all streams and water bodies, % of forested land composed of mixed softwood, % of forested land composed of birch-aspen, % of forested land composed of mixed hardwood-softwood, % of forested land composed of "wetland softwood", % of forested land composed of northern-hardwoods, sum of the areas of all water bodies characterized by alder-willow, sum of the areas of all water bodies characterized by emergent herbaceous vegetation/ sum of the area (ha) of all water bodies, sum of the areas of all water bodies characterized by floating-leaf vegetation, sum of the areas of all water bodies characterized by emergent herbaceous vegetation, sum of the areas of all water bodies characterized by ericaceous vegetation, herbaceous cover, shrub cover, canopy cover, tree density sclerophylous, visual obstruction between 0 - 0.50 m, visual obstruction between 0.50 - 1.0 m, visual obstruction between 1.0 - 1.50 m |
| Elevation | elevation, slope | |
| Aquatic Variables | Water body characteristics | water depth, river length, stream velocity, river/stream width, average width of river, bottom structure of stream, mean shoreline diversity index(shape), bank types (shore type), average width of bank, number of pools, number of tree logs, area lake, tributary presence, sum of the perimeters of all water bodies, sum of the area (ha) of all water bodies, sum of all open water areas of all water bodies, average stream gradient over the entire watershed, total dissolved solids, pH, flow zones, water temperature, distance to shore, bottom slope, shoreline complexity |
| River Hierarchy | distance to rivers of high hierarchy(3,4, 5), distance to rivers of low hierarchy(1,2), rivers(hierarchy), sum of the perimeters of all water bodies, sum of the area (ha) of all water bodies, sum of all open water areas of all water bodies, total length of all first-order stream, total length of all second-order stream segments, total length of all third-order stream segments, total stream length over all stream orders, total point-to-point length of all first-order streams, total point-to-point length of all second-order streams, total point-to-point length of all third-order streams, total point-to-point stream lengths over all orders, ratio1 (total length of all first-order stream / total point-to-point length of all first-order streams), ratio2 (total length of all second-order stream segments / total point-to-point length of all second-order streams), ratio3 (total length of all third-order stream segments/ total point-to-point length of all third-order streams), ratiot (total stream length over all stream orders/ total point-to-point stream lengths over all orders) average stream gradient over all first-order streams, average stream gradient over all second-order streams, average stream gradient over all third-order streams | |
| Predator -Prey/Competition variables | Competition | mink presence |
| Resource availability | refuge availability, % of all wetlands with active beaver sign, % of all wetlands with active or inactive beaver sign |
Table A10 - Metrics used at the regional scale.
Metrics in bold where found to be significant at this scale. Many studies do not consider variable significance in their analysis.
| Classification | Variables | Metrics |
| Disturbance variables | Roads | distance to roads, sum of road km within the watershed/watershed area |
| Population | distance from cities, distance to towns, human population density, location of homes | |
| Land use | proportion of survey area comprised of cropland, proportion of watershed comprised of cropland, frequency of dry herbaceous cropland in a 5-km radius, frequency of arboreal cropland in a 5-km radius, frequency of heterogeneous agricultural areas in a 5-km radius, high intensity development, low intensity development, proportion of watershed comprised of urban, (commercial, industrial, transportation, and recreation), distance from surface excavation, distance from productive areas | |
| Others | the site was a reservoir, location of fishing nets (5.1 km sections), disturbance, stream distance of site to nearest of border line for either Missouri or Oklahoma, distance to the nearest otter release site (km) | |
| Climate variables | Temperature | mean annual temperature, minimum daily temperature, maximum daily temperature |
| Precipitation | mean annual precipitation, mean daily precipitation, maximum daily precipitation | |
| Terrestrial variables | Vegetation variables | riparian vegetation cover, land cover, bankside fine scale land cover, coarse scale extra-riparian CORINE land cover, vegetation type, distance from riparian vegetation, proportion of survey area buffer comprised of woodland, proportion of watershed comprised of woodland, frequency of deciduous forest in a 5 km radius, frequency of sclerophylous vegetation in a 5 km radius, proportion of survey area comprised of grassland, proportion of watershed comprised of grassland, upland natural, non-coastal wetlands, dominant vegetative land cover, amount of non-river channel wetland area |
| Elevation | elevation, slope, aspect, convexity (hunting efficiency) | |
| Aquatic Variables | Water body characteristics | water depth, bank height, bankfull height, bank slope, river/stream width, survey segment sinuosity, flow accumulation, river water level, water quality, AMNET/FIBI water quality, AMNET/FIBI habitat quality, the waterbody is 303(d) impaired, distance from water (rivers), distance to the closest lake/pond, freshwater, long-term median flow rate of the river (ft3/s), last five year-dry history |
| River Hierarchy | the site was a 3rd order stream, the site was a 4th order stream, the site was a 5th order stream, the site was a 6th–7th order stream, sum of all open water areas of all water bodies, sum of the waterbody perimeters/sum of waterbody areas for entire watershed, sum of stream (3rd order) km within the watershed/watershed area, number of waterbodies within the watershed/ watershed area | |
| Predator -Prey/Competition variables | Competition | mink presence |
| Resource availability | beaver presence, probability of beaver occupancy | |
| Food resources | fish biodiversity | |
| Other | Cemetery, managed wetlands, schools, flats, tidal areas, bays, among others |
Table A11 - Metrics used at the country scales.
Metrics in bold where found to be significant at this scale. Many studies do not consider variable significance in their analysis.
| Classification | Variables | Scale |
| Disturbance variables | Roads | distance to the nearest highway, number of major roads, park roads and paved roads crossing the watershed, national road density, secondary road density, roads, total highway and roads density, presence of valley roads within 1 km, main roads, secondary roads, highway density, density of habitat cells (%of cell in the neighborhood occupied by roads) |
| Population | distance to the nearest town with more than 100,000 inhabitants, distance to the nearest town with more than 500, 000 inhabitants, distance to small urban settlement, distance to large urban settlement, human population density, mean density of human population | |
| Tourism | hotels per km, vehicles per km, vacancies in tourist apartments per km, total tourist vacancies per km, vacancies in camping sites per km | |
| Land use | agriculture, percentage of agricultural area, relative pasture area, relative cropland area, agricultural/livestock as adjacent area, proportion of agriculture area, land use, percentage of urban area, proportion of urban area, no vegetation as adjacent area, distance from industrial areas, distance from mines, nearest distance from dam reservoirs | |
| Others | water use, pollution | |
| Climate variables | Air humidity | mean relative air humidity in January, mean relative air humidity in July, annual relative air humidity range |
| Evapotranspiration | annual potential evapotranspiration, annual actual evapotranspiration, mean annual potential evapotranspiration, mean annual actual | |
| Temperature | mean temperature in January, mean temperature in July, mean annual temperature, annual temperature range, average monthly mean temperature, average monthly minimum temperature, average monthly maximum temperature, daily temperature range, maximum temperature of the warmest month, minimum temperature of the coldest month | |
| Precipitation | mean annual number of days with precipitation, average monthly precipitation, mean annual precipitation, maximum precipitation in 24h, relative maximum precipitation, precipitation seasonality, annual days of precipitation, precipitation of the driest month, precipitation of the wettest month, pluviometric irregularity | |
| Others | mean annual insolation, mean annual solar radiation, mean annual number of frost days, mean daily solar radiation, number of bioclimatic belts | |
| Terrestrial variables | Vegetation variables | density of bank vegetation, land cover, diversity of density of riparian vegetation (Simpson index), riparian vegetation width < 20 m, open riparian vegetation, dense riparian vegetation, riparian vegetation width>20 m, semi-dense riparian vegetation, forestry (%), relative woodland area, temu pitra swamp forest, exotic forest plantations as adjacent area, native vegetation as adjacent area, absence of riparian vegetation, upland natural, non-coastal wetlands, number of phytogeographic sectors |
| Elevation | elevation/altitude, slope, aspect, mean altitude, minimum altitude, maximum altitude, altitude range, convexity (hunting efficiency), acclivity | |
| Others | mean annual run-off, soil permeability, west coordinate, south coordinate, mean latitude, mean longitude | |
| Aquatic Variables | Water body characteristics | water depth, river slope, anastomosed river length, current type, narrow river, medium river, wide river, river/stream width, straight river, meandric river, shore type, streams, habitat type, average river elevation, total watercourses, hydrographic network |
| River Hierarchy | stream order, first order rivers, second order rivers, third order rivers, fourth and fifth order rivers | |
| Predator -Prey/Competition variables | Food resources | freshwater crab, freshwater crayfish, food availability |
| Others | other possible factors e.g. pollution, dry section of water body |
Table A12 - Metrics used at the continental scale.
Many studies do not consider variable significance in their analysis.
| Classification | Variables | Metrics |
| Disturbance variables | Roads | roads, distance to roads |
| Population | distance to the nearest town with more than 100,000 inhabitants, human population density | |
| Land use | industrial areas | |
| Climate variables | Precipitation | annual precipitation, mean precipitation driest quarter, mean precipitation wettest quarter |
| Terrestrial variables | Vegetation variables | forest |
| Elevation | elevation/altitude | |
| Aquatic Variables | Water body characteristics | % lake |
| River hierarchy | % rivers 1-2 Strahler order, % rivers 3–5 Strahler order, % rivers 6–9 Strahler order |
Table A13 - Metrics used at the geographic extent scale. Metrics in bold where found to be significant at this scale. Many studies do not consider variable significance in their analysis.
| Classification | Variables |
Metrics |
Disturbance variables |
Population |
human population density |
Climate variables
|
Temperature |
annual temperature, temperature standard, isothermality |
Precipitation |
annual precipitation, precipitation of the driest months, precipitation seasonality, precipitation of the warmest quarter |
|
Terrestrial variables
|
Vegetation variables |
vegetation cover |
Elevation |
elevation/altitude |
|
Aquatic Variables |
Water body characteristics |
percentage of water bodies |
Appendix A1 – Variables used for different otter species
Appendix A2 - Advantages and disadvantages of modeling approaches
Appendix A3 - Appendix A3 – Metrics used at each scale