Introduction

This document summarises the Revised estimates of the ACT Urban Habitat and Connectivity Project expert elicitation for the seven designated taxon groups using the IDEA protocol (refer to Hemming et al. 2018 “A practical guide to structured expert elicitation using the IDEA protocol” and Burgman 2016 “Trusting Judgements: How to get the best out of experts”).

For each question asked in the expert elicitation workshops, we have aggregated the results for each taxon group, with visualised aggregated estimates from each taxon group being denoted by a taxon group on the x- axis. The visualised aggregated scores exclude taxon groups, where the metric was not considered important/relevant for habitat or connectivity.

The intervals displayed are for a Four-Step Elicitation and aggregated results are based on arthmetic means for lower, upper and best estimates with credible intervals standardised to 80% confidence.

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Structural habitat metrics

The next series of visualisations relate to structural habitat metrics.

Structural habitat metrics describe how the various elements of a species’ habitat are arranged in space. For example, some arboreal species may need tree canopies a certain distance apart to be able to successfully navigate from one to the next. Another species might require grass heights of a certain amount to escape predation, whilst another species might only be able to persist within a certain distance from a water body.

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Preferred distance between tree canopies

This could be related to the amount of shade the taxon group prefers or is tolerant of in its preferred habitat, the distance an arboreal species can move from one tree to the next without going along the ground, or some other feature of the taxon groups’ general biology or life history. This metric considers the availability of both exotic and native tree species in the environment, as well as both young and mature trees (> 3m height). The answer to this question will give an equivalent score to something like “percentage canopy cover”, which might be a more familiar (but harder to map) version of this metric.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat tree_canopy 0.86 607 20 39 23 80 7
Aquatic_riparian_reptiles_and_m structural_habitat tree_canopy 7.75 88 27 28 28 80 4
Freshwater_fish_crayfish structural_habitat tree_canopy 1.20 440 11 31 11 80 5
Grassland_reptiles structural_habitat tree_canopy 47.89 858 101 110 102 80 9
Insect_pollinators structural_habitat tree_canopy 6.60 320 40 46 40 80 5
Small_medium_terrestrial_mammal structural_habitat tree_canopy 1.60 48 11 11 11 80 10
Small_woodland_birds structural_habitat tree_canopy 7.12 155 41 43 41 80 8

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Percentage of trees which need to be native

This relates to the composition of the urban forest or remnant woodland in terms of native and exotic trees. What percentage of trees need to be native for an area to be suitable habitat for this species group? This will relate to things such as food availability or the year-round availability of canopy cover. For some species, only native trees will be beneficial whilst other species might happily utilise any tree species as part of core habitat structure.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat native_trees 8.6 88 44 52 49 80 7
Aquatic_riparian_reptiles_and_m structural_habitat native_trees 37.5 98 62 63 62 80 4
Freshwater_fish_crayfish structural_habitat native_trees 12.0 100 99 100 100 80 5
Grassland_reptiles structural_habitat native_trees 23.6 73 55 55 55 80 7
Insect_pollinators structural_habitat native_trees 14.0 100 72 74 73 80 5
Small_medium_terrestrial_mammal structural_habitat native_trees 45.0 94 77 79 78 80 10
Small_woodland_birds structural_habitat native_trees 31.9 90 65 66 66 80 8

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Preferred distance between mature trees

This metric aims to give an indication as to the density of mature trees which are required in habitat suitable for this species group. It relates to native trees only. This may be relevant to habitat metrics such as the availability of tree hollows, stags, or fallen branches for which mature trees can be considered a surrogate metric.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat mature_trees 4.7 957 49 111 54 80 7
Aquatic_riparian_reptiles_and_m structural_habitat mature_trees 27.5 100 52 54 52 80 4
Grassland_reptiles structural_habitat mature_trees 73.1 1826 750 769 757 80 8
Insect_pollinators structural_habitat mature_trees 55.2 510 115 124 116 80 5
Small_medium_terrestrial_mammal structural_habitat mature_trees 9.0 61 22 23 22 80 10
Small_woodland_birds structural_habitat mature_trees 24.0 189 74 77 75 80 8

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Preferred distance between mid-storey canopies

This metric might reflect the overall amount of mid-storey cover (0.5 - 3m height) required by a taxon group, or how far they can move between shrubs. This metric considers the availability of both exotic and native mid-storey species in the environment. The answer to this question will give an equivalent score to something like “percentage mid-storey canopy cover”, which might be a more familiar (but harder to map) version of this metric.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Grassland_reptiles structural_habitat mid_canopy 48.8 1480 687.6 703.6 695.0 80 8
Insect_pollinators structural_habitat mid_canopy 8.8 300 42.9 49.0 43.8 80 4
Small_medium_terrestrial_mammal structural_habitat mid_canopy 1.0 28 7.1 7.5 7.2 80 10
Small_woodland_birds structural_habitat mid_canopy 7.8 113 36.2 37.8 36.6 80 8

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Percentage of native mid-storey vegetation

As for trees, this relates to the composition of the mid-storey vegetation and the percentage of that vegetation class which needs to be native for the area to provide suitable habitat structure for this species group. For example, for some species groups blackberry bushes might serve the same function as native shrubs.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Grassland_reptiles structural_habitat native_mid 16 82 57 66 59 80 6
Insect_pollinators structural_habitat native_mid 18 100 72 74 73 80 5
Small_medium_terrestrial_mammal structural_habitat native_mid 30 96 64 66 65 80 10
Small_woodland_birds structural_habitat native_mid 8 89 58 59 59 80 8

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Preferred distance from ground layer vegetation

This metric enables mapping of the potential distribution for those species which are tied in some way to ground layer vegetation. This might be a small species which lives within the grass layer (e.g. invertebrates, reptiles) or a larger species which relies on grass as food (e.g. kangaroos). How far will this taxon group be found from ground-layer vegetation?

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat ground_layer 1.29 738.6 9.3 24.2 10.0 80 7
Aquatic_riparian_reptiles_and_m structural_habitat ground_layer 2.50 32.5 21.6 22.2 22.0 80 4
Grassland_reptiles structural_habitat ground_layer 0.27 7.9 1.3 2.1 1.6 80 11
Insect_pollinators structural_habitat ground_layer 0.40 161.0 28.1 31.2 28.4 80 5
Small_medium_terrestrial_mammal structural_habitat ground_layer 1.00 10.9 2.9 3.1 2.9 80 10
Small_woodland_birds structural_habitat ground_layer 0.00 41.6 3.8 4.6 3.9 80 7

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Percentage of native ground layer vegetation

This metric relates to the composition of the ground storey vegetation (grasses, rushes, forbs, sedges; < 0.5m height). What is the percentage of the ground layer vegetation which needs to be native to provide suitable habitat for this taxon group?

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat native_ground 0.86 91 41 54 53 80 7
Aquatic_riparian_reptiles_and_m structural_habitat native_ground 40.00 90 62 63 62 80 4
Grassland_reptiles structural_habitat native_ground 19.58 96 72 73 73 80 12
Insect_pollinators structural_habitat native_ground 8.00 98 56 72 64 80 5
Small_medium_terrestrial_mammal structural_habitat native_ground 35.00 94 72 74 74 80 10
Small_woodland_birds structural_habitat native_ground 13.12 94 63 65 64 80 8

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Minimum height of ground layer vegetation

This metric relates to the average height (excluding seed stalks or other reproductive structures) of grasses, sedges, rushes, forbs and other ground layer vegetation. It might affect things like the availability of food sources (e.g. grass seeds) or opportunities for small animals to escape from predators. What is the minimum height of ground layer vegetation that provides suitable habitat for this taxon group?

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat min_height_ground 10.3 36 16 25 20 80 7
Aquatic_riparian_reptiles_and_m structural_habitat min_height_ground 15.0 40 25 25 25 80 4
Grassland_reptiles structural_habitat min_height_ground 5.0 18 10 10 10 80 12
Small_medium_terrestrial_mammal structural_habitat min_height_ground 10.0 52 27 28 27 80 10
Small_woodland_birds structural_habitat min_height_ground 3.7 29 11 11 11 80 7

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Maximum height of ground layer vegetation

As above, but this time please describe the maximum height of ground layer vegetation that provides suitable habitat for this taxon group? It might affect things like the ability of a species to effectively move through ground layer vegetation, or figd suitable burrowing sites, or access to solar radiation.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat max_height_ground 30 76 44 60 48 80 7
Aquatic_riparian_reptiles_and_m structural_habitat max_height_ground 36 86 50 51 50 80 4
Grassland_reptiles structural_habitat max_height_ground 14 36 21 21 21 80 12
Small_medium_terrestrial_mammal structural_habitat max_height_ground 32 84 49 51 50 80 10
Small_woodland_birds structural_habitat max_height_ground 12 52 23 24 23 80 8

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Preferred spacing between emergent vegetation

This metric relates to the spatial distribution of emergent vegetation in waterways, which may affect things like the availability of perch sites for dragonflies, or the availability of anchoring points for frog spawn. This metric considers the availability of both exotic and native vegetation in the environment. The answer to this question will give an equivalent score to something like “percentage vegetative cover”, which might be a more familiar (but harder to map) version of this metric.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat emergent_veg 3.4 27 11 12 11 80 7
Aquatic_riparian_reptiles_and_m structural_habitat emergent_veg 5.5 25 12 13 12 80 4
Freshwater_fish_crayfish structural_habitat emergent_veg 2.4 84 13 14 13 80 5

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Percentage of emergent vegetation which needs to be native

This metric relates to the composition of the emergency aquatic vegetation. What is the percentage of the emergent aquatic vegetation which needs to be native to provide suitable habitat for this taxon group?

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat native_emergent 23 85 49 59 56 80 7
Aquatic_riparian_reptiles_and_m structural_habitat native_emergent 26 92 46 59 52 80 4
Freshwater_fish_crayfish structural_habitat native_emergent 20 100 93 95 95 80 5

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Distance found from a permanent waterbody

This metric enables mapping of the potential distribution for those species which are tied in some way to a permanent waterbody. This might be a small species which is semi-aquatic (e.g. some frogs, turtles) or a larger species which relies on permanent water to drink (e.g. some birds and mammals). How far will this taxon group be found from permanent water?

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians structural_habitat waterbody 110.7 2021 297 375 304 80 7
Aquatic_riparian_reptiles_and_m structural_habitat waterbody 7.8 382 38 43 38 80 4
Insect_pollinators structural_habitat waterbody 6.7 800 214 487 350 80 3

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Non-structural habitat metrics

The next series of visualisations relate to non-structural habitat metrics.

This section asks questions regarding the non-structural elements which dictate habitat suitability for each taxon group. These includes things such as the amount of light which is tolerable at the time the species is active, or appropriate thermal conditions.

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Maximum tolerable night-time light levels

This metric relates to the maximum tolerable light level which is associated with suitable habitat for this taxon group. It relates to the amount of artificial light provided at night in the urban environment (e.g from streetlights, or buildings). For some species, artificial light may disrupt foraging behaviours, mate figding behaviours, or circadian rhythm.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians non_structural_habitat night_light 0.19 80.21 4.29 6.62 4.37 80 7
Aquatic_riparian_reptiles_and_m non_structural_habitat night_light 0.05 0.55 0.26 0.30 0.30 80 2
Freshwater_fish_crayfish non_structural_habitat night_light 0.04 8.20 0.24 0.73 0.24 80 5
Grassland_reptiles non_structural_habitat night_light 1.53 717.89 21.21 35.52 21.61 80 7
Insect_pollinators non_structural_habitat night_light 2.06 212.04 4.94 21.13 5.06 80 5
Small_medium_terrestrial_mammal non_structural_habitat night_light 1.91 21.38 4.26 4.71 4.39 80 8
Small_woodland_birds non_structural_habitat night_light 2.31 22.33 6.37 7.62 6.54 80 7

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Maximum tolerable surface temperature

This metric relates to the maximum surface temperature which is associated with suitable habitat for this taxon group. Surface temperature is the temperature which a laser thermometer would record if it was pointed to the ground. This metric is likely to be relevant to small terrestrial species, such as reptiles.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians non_structural_habitat surface_temp 19 33 24 26 25 80 7
Aquatic_riparian_reptiles_and_m non_structural_habitat surface_temp 33 43 37 37 37 80 3
Grassland_reptiles non_structural_habitat surface_temp 32 58 43 43 43 80 12
Insect_pollinators non_structural_habitat surface_temp 34 78 36 53 39 80 3

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Maximum tolerable ambient temperature

This metric relates to the maximum ambient temperature which is associated with suitable habitat for this taxon group. Ambient temperature is the temperature which a mercury thermometer would record if it was suspended in the air out of direct sunlight (e.g. in the shade). This metric is likely to be relevant to larger terrestrial species, such as kangaroos, as well as arboreal species such as birds and bats.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians non_structural_habitat ambient_temp 21 36 29 30 30 80 7
Aquatic_riparian_reptiles_and_m non_structural_habitat ambient_temp 32 44 39 39 39 80 3
Grassland_reptiles non_structural_habitat ambient_temp 30 41 36 36 36 80 12
Insect_pollinators non_structural_habitat ambient_temp 36 48 40 41 41 80 5
Small_medium_terrestrial_mammal non_structural_habitat ambient_temp 35 46 40 40 40 80 10
Small_woodland_birds non_structural_habitat ambient_temp 31 43 37 37 37 80 8

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Maximum tolerable water temperature (aquatic only)

This metric relates to the maximum water temperature which is associated with suitable habitat for this taxon group. Water temperature is the temperature which a mercury thermometer would record if it was pointed held under the surface of the water, out of direct sunlight. This metric is likely to be relevant to fish and other aquatic organisms, as well as species which lay eggs in the aquatic environment.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians non_structural_habitat max_w_temp 21 31 23 26 25 80 7
Aquatic_riparian_reptiles_and_m non_structural_habitat max_w_temp 24 32 26 27 26 80 4
Freshwater_fish_crayfish non_structural_habitat max_w_temp 16 31 24 24 24 80 5

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Minimum tolerable water temperature (aquatic only)

This metric relates to the minimum water temperature which is associated with suitable habitat for this taxon group. Water temperature is the temperature which a mercury thermometer would record if it was pointed held under the surface of the water, out of direct sunlight. This metric is likely to be relevant to fish and other aquatic organisms, as well as species which lay eggs in the aquatic environment.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians non_structural_habitat min_w_temp 4.1 11.7 7.3 8.8 7.6 80 7
Aquatic_riparian_reptiles_and_m non_structural_habitat min_w_temp 1.5 6.8 4.5 4.5 4.5 80 4
Freshwater_fish_crayfish non_structural_habitat min_w_temp 3.0 12.0 6.5 6.7 6.6 80 5

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Habitat patch size and typical dispersal distances

The next series of visualisations relate to habitat patch size and typical dispersal distances.

This section asks questions regarding habitat patch sizes and typical dispersal distances for your selected taxon group.

Habitat patch size is explored for both core habitat (where the species lives full time) and corridors (areas the species might move through when dispersing, or when moving between connected habitat patches). Dispersal capability covers how far a species will typically move within and between habitat patches (e.g. within a home range), as well as how far they typically will move during a major dispersal event, e.g. when migrating or dispersing to a new home range.

The answers to these questions will help us to understand how far apart different patches of habitat can be whilst still being connected for a taxon group, as well as what the aspirations should be in terms of the total extent of connected habitat at the landscape or regional scale to facilitate typical dispersal patterns for the species. Below, we ask you to provide your upper, lower and best estimates for a range of metrics related to patch size and movement behaviour.

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Minimum suitable core habitat patch width

This metric relates to the minimum dimensions of an area which could be considered suitable core habitat for the taxon group. By core habitat, this would mean the area was able to provide all resources required by the species, including food, shelter, mates, etc.

For example, for a small mammal, the edge effects associated with a narrow strip of suburban woodland nestled between two rows of residential blocks may prevent it being classified as suitable core habitat. For an aquatic species, a stream may need to be some minimum width to provide sufficient core habitat for the species to move around in. If a core habitat patch in this instance is considered to have a rectangular shape, what would be the minimum width of the shorter side, regardless of how long the longer side might be?

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians patch_size min_width_core 21.9 177 81.5 88.2 84.3 80 7
Aquatic_riparian_reptiles_and_m patch_size min_width_core 5.0 24 8.4 8.7 8.5 80 4
Freshwater_fish_crayfish patch_size min_width_core 2.6 33 4.6 5.0 4.6 80 5
Grassland_reptiles patch_size min_width_core 75.8 298 172.6 175.5 173.8 80 12
Insect_pollinators patch_size min_width_core 66.2 600 230.9 251.0 241.0 80 5
Small_medium_terrestrial_mammal patch_size min_width_core 49.3 1273 127.3 176.4 130.0 80 10
Small_woodland_birds patch_size min_width_core 72.5 2075 322.8 358.4 327.5 80 8

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Minimum suitable corridor habitat patch width

This metric relates to the minimum dimensions of an area which could be considered suitable habitat for the taxon group to move through, e.g. between different patches of ‘core’ habitat, or when dispersing (e.g. as a sub-adult looking for a new home range). Corridor habitat would need to provide all resources required by the species to effectively move through the urban space, e.g. suitable perch sites for birds, suitable protection from predation for mammals and reptiles.

For example, for a small mammal, the edge effects associated with a narrow strip of suburban woodland nestled between two rows of residential blocks may prevent it being classified as suitable core habitat, but it might be sufficient habitat to facilitate movement through the area. For an aquatic species, a stream may need to be some minimum width to provide sufficient core habitat for the species to move around in, however the same species may be able to navigate a narrow culvert if just being used as part of a movement corridor. If a movement corridor in this instance is considered to have a rectangular shape, what would be the minimum width of the shorter side, regardless of how long the longer side might be?

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians patch_size min_width_corridor 2.6 26 9.9 12.9 11.3 80 7
Aquatic_riparian_reptiles_and_m patch_size min_width_corridor 3.7 13 4.3 4.5 4.3 80 3
Freshwater_fish_crayfish patch_size min_width_corridor 0.8 26 1.8 2.2 1.8 80 5
Grassland_reptiles patch_size min_width_corridor 11.2 131 35.9 37.3 36.2 80 12
Insect_pollinators patch_size min_width_corridor 5.4 168 31.4 36.1 32.4 80 5
Small_medium_terrestrial_mammal patch_size min_width_corridor 17.9 171 54.7 57.5 55.5 80 10
Small_woodland_birds patch_size min_width_corridor 8.8 91 27.8 29.3 28.1 80 8

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Minimum suitable core habitat depth (aquatic only)

This metric relates to aquatic habitat only. As per the minimum width measurements above, what is the minimum depth of a habitat patch which would enable it to be suitable as core habitat for this taxon group?

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians patch_size min_depth_core 0.29 0.89 0.59 0.66 0.6 80 7
Aquatic_riparian_reptiles_and_m patch_size min_depth_core 1.50 4.00 2.24 2.28 2.2 80 4
Freshwater_fish_crayfish patch_size min_depth_core 0.30 3.50 1.39 1.43 1.4 80 5

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Minimum suitable corridor habitat depth (aquatic only)

This metric relates to aquatic habitat only. As per the minimum width measurements above, what is the minimum depth of a habitat patch which would enable it to be suitable as a movement corridor for this taxon group?

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Aquatic_riparian_reptiles_and_m patch_size min_depth_corridor 0.38 1.6 1.00 1.01 1.00 80 4
Freshwater_fish_crayfish patch_size min_depth_corridor 0.16 2.0 0.61 0.64 0.62 80 5

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Typical dispersal distance when seeking new home range/territory

This metric describes how far dispersing individuals from this taxon group will travel, usually to figd a new home range or territory. This metric assumes the availability of continuous habitat.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians patch_size disperal_distance 76 2450 441 720 479 80 7
Aquatic_riparian_reptiles_and_m patch_size disperal_distance 400 4000 1361 1414 1375 80 4
Freshwater_fish_crayfish patch_size disperal_distance 11 820 88 112 90 80 5
Grassland_reptiles patch_size disperal_distance 18 467 67 75 68 80 12
Insect_pollinators patch_size disperal_distance 15 680 107 145 110 80 5
Small_medium_terrestrial_mammal patch_size disperal_distance 110 3730 753 831 765 80 10
Small_woodland_birds patch_size disperal_distance 210 7375 808 988 825 80 8

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Typical movement distance within established home range/territory

This metric describes how far an individual typically moves within a suitable habitat patch. It could be considered as the distance between the centre and the edge of a home range or territory.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians patch_size movement_within 14.4 436 55 75 61 80 7
Aquatic_riparian_reptiles_and_m patch_size movement_within 800.0 3250 1614 1647 1625 80 4
Freshwater_fish_crayfish patch_size movement_within 7.4 226 30 33 30 80 5
Grassland_reptiles patch_size movement_within 18.7 173 53 55 54 80 12
Insect_pollinators patch_size movement_within 22.2 800 182 340 200 80 5
Small_medium_terrestrial_mammal patch_size movement_within 87.0 1620 521 562 529 80 10
Small_woodland_birds patch_size movement_within 157.5 812 398 418 406 80 8

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Typical capacity for movement outside of suitable habitat (in the absence of a physical barrier)

This metric aims to quantify how far this taxon group can or will typically move outside of areas mapped as suitable habitat. For example, a kangaroo might be able to cross a road, even though a road is not classified as suitable habitat, so long as there are no wildlife exclusion fences. A cockatoo might be able to move across a suburb between one suitable woodland habitat patch and another.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians patch_size capacity_movement 9.4 350 63 81 67 80 7
Aquatic_riparian_reptiles_and_m patch_size capacity_movement 75.0 700 222 237 225 80 4
Freshwater_fish_crayfish patch_size capacity_movement 13.0 340 32 37 32 80 5
Grassland_reptiles patch_size capacity_movement 1.8 207 29 39 31 80 12
Insect_pollinators patch_size capacity_movement 33.0 540 207 228 214 80 5
Small_medium_terrestrial_mammal patch_size capacity_movement 33.6 699 98 110 100 80 10
Small_woodland_birds patch_size capacity_movement 180.0 9502 955 1129 977 80 8

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Barriers to movement

The next series of visualisations relate to barriers to movement.

This is the figal section of this survey. This section asks questions regarding barriers to movement in the urban space, which might be represented by vertical barriers (fences, walls, buildings, gutters), water barriers (lakes, streams, rivers), substrate barriers (e.g. concrete or bitumen) or barriers relating to the use of an area by people (traffic, pedestrians). By quantifying these barriers we can use remote sensing data to identify their location in the urban environment and demonstrate functional habitat fragmentation.

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Maximum crossable extent of paved surface (incl. concrete drains)

This metric aims to capture the distance this taxon group can move across a paved surface, e.g. concrete or bitumen. Examples might include bike or pedestrian paths, roads and driveways, concrete drainage channels, tennis courts, car parks, etc. For reptiles, for example, a taxon group may choose this substrate as a basking site but not be able to move a long distance due to the lack of suitable habitat cover to protect from predation. For fish, platypus or turtles, there may be some maximum distance a species can move through an artificial waterbody (e.g. a concrete drainage channel) between naturalised pools or streams.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians barriers paved_surface 12.14 108 26 36.5 29.3 80 7
Aquatic_riparian_reptiles_and_m barriers paved_surface 3.83 31 16 16.5 16.2 80 4
Freshwater_fish_crayfish barriers paved_surface 0.25 55 12 13.2 11.8 80 4
Grassland_reptiles barriers paved_surface 1.88 24 6 6.3 6.1 80 12
Small_medium_terrestrial_mammal barriers paved_surface 6.78 50 15 15.4 14.9 80 9

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Maximum crossable height of vertical structures

This metric aims to determine how much of a vertical structure will impede movement by this taxon group. For example, turtles may not be able to climb up a steep roadside curb, however for a gecko a vertical structure equivalent to a multi-storey building may not be prevent movement. Birds may be able to cross vertical barriers of any height, unless they are flightless.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians barriers max_height_building 0.04 2.98 0.34 0.38 0.35 80 7
Aquatic_riparian_reptiles_and_m barriers max_height_building 0.58 0.92 0.71 0.71 0.71 80 4
Freshwater_fish_crayfish barriers max_height_building 0.00 0.24 0.07 0.07 0.07 80 5
Grassland_reptiles barriers max_height_building 0.14 0.92 0.26 0.27 0.26 80 12
Small_medium_terrestrial_mammal barriers max_height_building 1.52 8.83 3.29 3.42 3.32 80 9

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Maximum crossable extent of water body

This metric aims to quantify the distance this taxon group can move across a permanent waterbody. In some instances, larger species such as kangaroos may be readily able to navigate a small stream by hopping from one side to the other, however the same might not be possible for a small grassland reptile.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Amphibians barriers max_waterbody 14.29 195.7 28.98 39.63 30.71 80 7
Grassland_reptiles barriers max_waterbody 0.42 7.6 0.82 0.97 0.83 80 12
Small_medium_terrestrial_mammal barriers max_waterbody 6.44 590.2 14.31 36.93 14.44 80 9

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Tolerable vehicle traffic flow (incl. boats) during active period (day/night)

This metric aims to quantify the level of vehicle traffic (including boats in an urban waterbody) which would represent a barrier to this taxon group. The number should be based on the amount of traffic occurring during the species’ active part of the day or night. For example, an echidna may be willing and able to cross a road at night when there is little traffic, however during the day an increased traffic volume may result in the road (or rather, the traffic on the road) becoming a barrier for this species. A similar approach can be applied to aquatic and riparian species in terms of boat traffic.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Aquatic_riparian_reptiles_and_m barriers traffic_flow 1.8 12 5.7 5.9 5.8 80 4
Grassland_reptiles barriers traffic_flow 3.4 27 6.4 8.7 6.6 80 10
Small_medium_terrestrial_mammal barriers traffic_flow 3.1 28 7.7 10.1 8.0 80 9

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Tolerable pedestrian traffic flow (incl. swimming) during active periods (day/night)

This metric aims to quantify the level of pedestrian traffic (including swimmers in an urban waterbody) which would represent a barrier to this taxon group.The number should be based on the amount of pedestrians passing during the species’ active part of the day or night. A similar approach can be applied to aquatic and riparian species in terms of people swimming in a waterbody.

For example, a kangaroo may be willing and able to cross school playground at dusk in summer when there are few people about, however during winter an increased use of the school oval for organised sports in the evening may result in the grassy area becoming a barrier for this species.

Taxon Variable Metric Lower Upper lCI uCI Best Confidence N_Experts
Aquatic_riparian_reptiles_and_m barriers pedestrian_flow 9.0 102 69.0 71 70.5 80 4
Grassland_reptiles barriers pedestrian_flow 2.8 35 10.5 14 11.5 80 12
Small_medium_terrestrial_mammal barriers pedestrian_flow 3.4 42 8.5 13 9.6 80 9

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\(~\) Barriers <- plot_grid(ps, vh, gd, wbe, tf, pf, labels = c(“A”, “B”, “C”, “D”, “E”, “F”), ncol = 3, nrow = 2)