Introduction

This document summarises the Round 1 - Initial estimates of the Fine Scale Metrics for ACT Urban Habitat and Connectivity Project expert elicitation for aquatic/riparian reptiles and mammals 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, we have summarised the results. All responses from the expert elicitation remain anonymous, with visualised experts estimates being denoted by a number on the x- axis. Below each visualised estimate, the comments provided by experts are collated.

The intervals displayed are for a Three-Step Elicitation.

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Structural habitat metrics

The next series of visualisations relate to structural habitat metrics.

Structural habitat metrics describe the finer scale structural elements of a species’ habitat and how the various features are arranged in space. For example, some species may need access to bare ground for nesting to be able to successfully occupy a habitat patch. This would be a structural requirement.

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Preferred % cover of rocks

Access to rocky substrate may relate to things such as habitat refugia, basking sites for reptiles, or food resources (for aquatic species). What percentage cover of rocky substrate is required for an area to be preferred habitat for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 10 2 15 Although not very important to turtles, it is important for the dragons and snakes. 60 Aquatic_riparian percent_rocks Initial
67 0 0 75 There has not been extensive research in this area. Freshwater turtles are found in water bodies with rocky substrates, but artifical riprap along shorelines can be a death trap. Turtles climbing over the rocks fall into the cracks and get stuck. They then cook/die of exposure. This has been observed in particular at Calperum Station in Renmark, SA. 10 Aquatic_riparian percent_rocks Initial
45 50 25 85 rocky substrate essential as a food source for platypus and rakali but not their sole food source 50 Aquatic_riparian percent_rocks Initial
Aggregated 20 9 58 NA 40 Aquatic_riparian percent_rocks Aggregated

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Preferred % cover of bare ground

Access to bare ground may relate to things such as nesting sites (for burrowing or fossorial species) or spaces to hunt. What percentage of ground needs to be bare ground for an area to be preferred habitat for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 20 5.0 35 In a natural setting, there will be some variation in the amount of bare ground, or areas with naturally sparse vegetation, and turtles will look for those sites to nest (usually you can find several nests within those patches, otherwise they might move further distances to find that suitable habitat for nesting). 70 Aquatic_riparian percent_ground Initial
67 25 0.0 100 There has not been extensive research in this area. Turtles seem to survive in wetlands with bare substrate, but might prefer/do better in areas with aquatic vegetation. On land, limited coverage appears preferable for nesting habitat. 5 Aquatic_riparian percent_ground Initial
45 30 5.0 50 I can’t see platypus or rakali benefitting from bare ground at all but could tolerate a certain amount 50 Aquatic_riparian percent_ground Initial
Aggregated 25 3.3 62 NA 42 Aquatic_riparian percent_ground Aggregated

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Preferred % cover of grass thatch (dead, unattached grass)

Grass thatch is the layer of dead plant material that develops between the zone of green vegetation and the soil surface. We consider dead grass to be thatch once it is no longer attached to the parent plant. Grass thatch can be beneficial for some species (e.g. providing habitat for nesting) but detrimental for other species (e.g. obstructing movement). What percentage cover of grass thatch is consistent with an area being preferred habitat for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 3 0.0 5 I am not entirely sure if grass thatch is important for turtles, as they will dig their nests even with some sparse vegetation still alive in the top soil. I put lower estimates for this one, as perhaps it can be important for nesting for lizards. 30 Aquatic_riparian percent_thatch Initial
67 25 0.0 100 see previous 5 Aquatic_riparian percent_thatch Initial
45 50 25.0 100 I assume we’re including leaves in this ‘dead plant material’ definition? Leaves/grass is important for nesting material but also bug habitat when it settles in the water. 50 Aquatic_riparian percent_thatch Initial
Aggregated 26 8.3 68 NA 28 Aquatic_riparian percent_thatch Aggregated

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Preferred depth of grass thatch / leaf litter (cm)

The definition of grass thatch here is consistent with the previous question, however this question focuses on the depth of the grass thatch layer. What depth of grass thatch is consistent with preferred habitat for this taxon group? Consider the most appropriate depth of grass thatch in centimetres.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 0.0 0.00 0 I am not sure about the values for this question, so I put a zero for the answers (possibly not important for turtles, but important for other taxa in this group). 10 Aquatic_riparian thatch_depth Initial
67 2.0 0.00 5 see previous 5 Aquatic_riparian thatch_depth Initial
45 5.0 1.00 10 don’t know if depth is that important. Diversity would be more indicative of good riparian condition - ie if it’s all poplar leaves then maybe not that useful as habitat/material 50 Aquatic_riparian thatch_depth Initial
Aggregated 2.3 0.33 5 NA 22 Aquatic_riparian thatch_depth Aggregated

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Preferred % cover of leaf litter

Some species require access to leaf litter for food resources (e.g. arthropods and other invertebrate living in the leaf litter) or may require leaf litter as habitat refugia (for burrowing or fossorial species). What percentage of cover of leaf litter is consistent with preferred habitat for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 20 5 30 Leaf litter (specially from gum tress) is very important for turtles as they use it to aestivate during drought (when a wetland completely dries up, they might move to another permanent body of water, but it too far, they aestivate in the leaf litter). 60 Aquatic_riparian percent_litter Initial
67 0 0 100 see previous 5 Aquatic_riparian percent_litter Initial
45 50 25 100 se earlier comments on leaf litter 50 Aquatic_riparian percent_litter Initial
Aggregated 23 10 77 NA 38 Aquatic_riparian percent_litter Aggregated

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Preferred % grass cover (all grasses)

The percentage cover of grass might be important for some species based on refugia sites or food resources. What percentage of grass cover is consistent with preferred habitat for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 20 5.0 30 Grass cover itself might not be essential for turtles as a habitat requirement, but possibly important for the health of the creek/wetland, and potentially for other species in the group. Turtles preferred nesting sites are areas with sparse grass cover. 30 Aquatic_riparian percent_grass Initial
67 20 0.0 100 see previous 5 Aquatic_riparian percent_grass Initial
45 0 0.0 0 I would think grass is only important as cover/refuge and this need could be met by other ground cover plants. 50 Aquatic_riparian percent_grass Initial
Aggregated 13 1.7 43 NA 28 Aquatic_riparian percent_grass Aggregated

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Preferred total length of coarse woody debris (>10cm diameter incl. snags, stumps)

Coarse woody debris (CWD) refers to fallen dead trees and the remains of large branches on the ground in forests, grasslands and in aquatic ecosystems. Here we define CWD as being greater than 10 cm in diameter and including snags (aquatic) and tree stumps. CWD provides structure and refugia within a terrestrial habitat and changes physical and hydraulic properties in aquatic systems. CWD needs to be considered when managing forests for biodiversity but also for managing fire risk. What is the preferred total length of coarse woody debris required in an area to be preferred habitat for this taxon group? Consider the total length in metres in a one-hectare patch.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 20 10 30 This is probably not important for turtles, but possibly for lizards, so I’m considering some lower values. 30 Aquatic_riparian cwd_length Initial
67 0 0 0 turtles would do well crossing/nesting in ground covered in logs and stumps 100 Aquatic_riparian cwd_length Initial
45 35 20 50 snags provide habitat for rakali and platypus food 50 Aquatic_riparian cwd_length Initial
Aggregated 18 10 27 NA 60 Aquatic_riparian cwd_length Aggregated

Preferred % cover of floral resources

Floral resources refer to flowering plants which might provide food resources throughout the entire forest column (i.e. ground layer to canopy). What is the preferred percentage cover of floral resources in an area at any one time which is associated with preferred habitat for this taxon group? You might consider the percentage cover across a one-hectare patch if it helps, or another scale if that makes more sense to you. We encourage you to leave additional notes around any additional considerations you feel are necessary to support your response.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 20.0 5.0 30 Although the floral resources doesn’t seem to affect turtles, I’m considering some percentage here due to the health of the body of water and for microhabitat provision for turtles (leaf litter, for aestivation during drought). 40 Aquatic_riparian percent_floral Initial
67 0.0 0.0 0 floral cover will not affect FW turtles 100 Aquatic_riparian percent_floral Initial
45 0.0 0.0 0 N/A 70 Aquatic_riparian percent_floral Initial
Aggregated 6.7 1.7 10 NA 70 Aquatic_riparian percent_floral Aggregated

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Preferred number of flowering species (floral resource diversity)

A diversity of flowering plants throughout the entire forest column (i.e. ground layer to canopy) provides food resources across time and space. What is the preferred number of flowering species in an area at any one time for the habitat to be preferred for this taxon group? Consider the preferred number of flowering species across a one-hectare patch. We encourage you to leave additional notes around any additional considerations you feel are necessary to support your response.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 2.00 1.00 5.0 It seems that the diversity of trees doesn’t matter much for turtles, as long there is one large gum tree providing a good amount of leaf litter for turtles to aestivate. I’m thinking here in systems like in Mulligans Flat, where a yellow box and Blakely’s red gum can provide enough for it. 30 Aquatic_riparian min_flower_sp Initial
67 0.00 0.00 0.0 see previous 100 Aquatic_riparian min_flower_sp Initial
45 0.00 0.00 0.0 N/A 70 Aquatic_riparian min_flower_sp Initial
Aggregated 0.67 0.33 1.7 NA 67 Aquatic_riparian min_flower_sp Aggregated

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Minimum temporal availability of floral resources

A diversity of flowering plants throughout the entire forest column (i.e. ground layer to canopy) provides food and other resources across time. What is the minimum temporal availability of floral resources in an area for the habitat to be suitable for this taxon group, in terms of the number of months per year? (e.g. a score of 6 would indicate that flowering plants were available for at least 6 months of the year, although not necessarily continuously). We encourage you to leave additional notes around any additional considerations you feel are necessary to support your response.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 4.0 2.00 6 I’m considering here that by having some floral resource part of the year, it will provide some leaf litter if needed during a dry spell, for example. 30 Aquatic_riparian temp_floral Initial
67 0.0 0.00 0 see previous 100 Aquatic_riparian temp_floral Initial
45 0.0 0.00 0 N/A 70 Aquatic_riparian temp_floral Initial
Aggregated 1.3 0.67 2 NA 67 Aquatic_riparian temp_floral Aggregated

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Preferred % tree canopy cover (per ha)

The tree canopy provides structure (such as shade), habitat and resources for a range of species. Tree canopy cover may influence how a 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 accounts for the availability of canopy cover from exotic and native tree species in the environment, as well as both young and mature trees (> 3m height). Consider the percentage cover across one hectare patch.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 40 5 50 Canopy cover is also being considered here in terms of providing leaf litter for turtles during drought for aestivation. 50 Aquatic_riparian percent_canopy Initial
67 0 0 25 Turtles prefer open canopy for areas to nest under 50 Aquatic_riparian percent_canopy Initial
45 50 25 100 important for shading in the riparian zone and the leaf drop that provides bug habitat. 50 Aquatic_riparian percent_canopy Initial
Aggregated 30 10 58 NA 50 Aquatic_riparian percent_canopy Aggregated

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Preferred % cover of below surface vegetation (aquatic only)

This could be related to the amount of food resources the species group prefers or is tolerant of in its preferred habitat, the distance an aquatic species can move from one below surface vegetation patch to the next without being exposed to predators, or some other feature of the species groups’ general biology or life history. This metric considers the availability of both exotic and native below surface vegetation species in the aquatic environment.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 40 10 50 % of aquatic vegetation is important for juvenile turtles as they seek refuge from aquatic predators. It is also important for macroinvertebrates diversity and abundance, as they are a food source for turtles (adult and young). 60 Aquatic_riparian percent_below_veg Initial
67 50 0 100 FW turtles survive in areas with limited aquatic vegetation, but they probably do better in places where it is at least available. 50 Aquatic_riparian percent_below_veg Initial
45 45 25 65 I think this is more important for food source as don’t feel platypus and rakali are that vulnerable to predators under water 50 Aquatic_riparian percent_below_veg Initial
Aggregated 45 12 72 NA 53 Aquatic_riparian percent_below_veg Aggregated

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Preferred shape of bank and complexity

Streambank profiles affects stream temperature, water velocity, sediment input, refugia/cover and suitable habitat for fish. Because streambank complexity and the quality of habitat are closely linked, any change, such as erosion, can have large biological implications. This metric considers the shape and complexity of the streambank. This is measured as rugosity, the measure of small-scale variations of amplitude in the height of a surface. Rugosity can range from 0.01, a smooth, flat bank or concrete channel with no obstructions, to 0.10 in streams with large amounts of large woody debris and vegetation that impedes flow. What is the preferred bank shape for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 0.05 0.01 0.10 This possibly doesn’t influence much turtles, but it could affect the amount of turtle food (macroinvertebrates), but the presence of refuges and pools within a creek, which can benefit turtles while foraging. 30 Aquatic_riparian bank_shape Initial
67 0.01 0.01 0.06 Rugosity would not affect turtles most of the time, but it could impede their crossing. See my prior comment about riprap 50 Aquatic_riparian bank_shape Initial
45 0.07 0.05 0.10 Really guessing here but assume a need for bank complexity in order to build suitable burrows. Also for protection when moving in and out of the water. 35 Aquatic_riparian bank_shape Initial
Aggregated 0.04 0.02 0.09 NA 38 Aquatic_riparian bank_shape Aggregated

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Preferred slope of bank

Streambank profiles affect stream temperature, water velocity, sediment input, refugia/cover and suitable habitat and passage for aquatic and riparian species. Because streambank condition and the quality of habitat are closely linked, any change, such as erosion, can have large biological implications. This metric considers the angle of the streambank (artificial or natural substrate). What is a tolerable slope of bank to best support habitat structure and function for this taxon group? (e.g. allowing movement between the aquatic and riparian habitat, or supporting stream structure and function for small freshwater fish?) This expressed as the angle of the bank. What is the preferred bank angle for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 30 0.0 45 Turtles can move up through the slope but it the inclination is too much, that might act as a barrier. 50 Aquatic_riparian bank_slope Initial
67 0 0.0 70 turtles have been reported to climb fairly steep banks to exit rivers and wetlands 50 Aquatic_riparian bank_slope Initial
45 55 25.0 85 Don’t know enough about their burrow needs but am guessing that steeper banks would benefit them by giving them protections and enabling quick access in and out of burrows. Don’t know about thermal requirements of burrows and things like that which would likely influence choice of burrow site. 30 Aquatic_riparian bank_slope Initial
Aggregated 28 8.3 67 NA 43 Aquatic_riparian bank_slope Aggregated

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Physical chemical properties

The next series of visualisations relate to physical chemical properties.

Physical chemical properties mostly relate to the aquatic environments or soil.

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Preferred soil moisture content

Soil moisture content is the total amount of water, including the water vapor, in the soil. Soil moisture influences the vegetation species present and can affect burrowing and feeding activity of some fauna. This metric seeks to determine the preferred soil moisture content for the taxon group.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 10 5 15 Soil moisture is possibly important for turtle nests, but I’m uncertain of the best values for it, so this is a rough estimate. They should have some moisture in the soil so the eggs can develop during incubation, but possibly if too moist, that could reduce temperatures and increase the incubation period. 20 Aquatic_riparian soil_moisture Initial
67 25 25 30 Some soil moisture is needed for eggs to develop properly. This is a difficult thing to measure in the field. We typically replicate it with ~1:1 vermiculite to water in the lab. 1 Aquatic_riparian soil_moisture Initial
45 50 20 75 I’m sure there are optimum soil moisture levels for most native animals. Too dry will make burrow digging difficult and some moisture is important to maintain some humidity in burrows - particularly maternity burrows. 30 Aquatic_riparian soil_moisture Initial
Aggregated 28 17 40 NA 17 Aquatic_riparian soil_moisture Aggregated

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Preferred electrical conductivity (aquatic only)

Electrical conductivity is a measurement of the total combined salts/minerals in water and is used as a proxy for salinity. This metric seeks to determine the preferred electrical conductivity for the taxon group.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 0 0 0 Electrical conductivity possibly not important for turtles, as they can stand tough conditions and can live in pristine creeks to sewerage treatment ponds. 60 Aquatic_riparian elec_cond Initial
67 0 0 0 N/A 1 Aquatic_riparian elec_cond Initial
45 250 50 400 Higher EC will start to knock out pollution-sensitive bugs. While neither platypus or rakali need these types of bugs exclusively, a diversity of diet is better. 50 Aquatic_riparian elec_cond Initial
Aggregated 83 17 133 NA 37 Aquatic_riparian elec_cond Aggregated

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Preferred pH level (alkalinity; aquatic only)

A measure of the acidity or basicity (alkalinity). This metric seeks to determine the preferred pH level for the taxon group. The range goes from 0 to 14, with 7 being neutral. pH of less than 7 indicates acidity, whereas a pH of greater than 7 indicates a base. The pH of water is a very important measurement concerning water quality.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 7 5.0 9 As with the last question, some pH variation possibly doesn’t affect much turtles. Considering creeks/dams in Canberra, there will be sites more acidic (6) and some more alkaline (9), and turtles are still inhabiting these areas. 50 Aquatic_riparian pH_level Initial
67 7 7.0 7 I’m sure turtles can tolerate some range of pH variation, but I would be surprised if it was too far outside of neutral. They are probably better at it than fish or amphibians 50 Aquatic_riparian pH_level Initial
45 7 5.5 8 I would guess that pH outside these limits would have similar effects of Waterbug diversity as mentioned on EC page. 80 Aquatic_riparian pH_level Initial
Aggregated 7 5.8 8 NA 60 Aquatic_riparian pH_level Aggregated

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Preferred siltation levels

Siltation is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary or permanent) of fine sediments on stream or waterbody bottoms where they smother instream vegetation and cobbling occurs. Siltation is most often caused by soil erosion or sediment spill. This metric seeks to determine the maximum tolerable siltation for the taxon group within suitable habitat.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 0 0.0 0 I think this question might be related to the previous one, as siltation will increase turbidity as possibly have a similar effect on turtles? I put zero in the answers as I did not known what to answer in terms of siltation % and the possible correlation with turbidity. 5 Aquatic_riparian max_siltation Initial
67 50 0.0 100 Again, we find turtles in some pretty boggy, silty, gross water. I think they can tolerate it pretty well but they probably have some negative effects as a result. 25 Aquatic_riparian max_siltation Initial
45 25 10.0 40 see comments from previous page 50 Aquatic_riparian max_siltation Initial
Aggregated 25 3.3 47 NA 27 Aquatic_riparian max_siltation Aggregated

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Preferred tolerable turbidity

Turbidity is the degree of suspended solids in water that gives it a muddy colour. High concentrations of particulate matter affect light penetration, ecological productivity and habitat quality. This metric seeks to determine the preferred level of turbidity for the taxon group.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 20 9 200 It is known for some turtles that high turbidity levels over large periods of time or constant, it affects their ability to breath through their cloaca and they need to come to the surface more regularly. What usually happens in Canberra some increase in turbidity after storms, or in the case of bushfires, where high turbidity can remain for some weeks or months. They probably can deal with that for a while, but not much data on that too. 50 Aquatic_riparian max_turbidity Initial
67 50 0 100 Turtles can be reliably caught in water varying from super-clear to totally turbid. I don’t think it bothers them much. Whether it is good for them either way is unknown. 50 Aquatic_riparian max_turbidity Initial
45 15 0 40 High sedimentation smothers river substrates and effects bug habitat. Of all the WQ parameters, this one seems to have the most direct adverse impacts on platypus. Not as sure about rakali. 70 Aquatic_riparian max_turbidity Initial
Aggregated 28 3 113 NA 57 Aquatic_riparian max_turbidity Aggregated

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Preferred dissolved oxygen concentration

The amount of oxygen present within water, either presented as an absolute amount (mg/L) or as a percentage of the total oxygen saturation at a given temperature

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 10 1 14 Turtles can deal with anoxic conditions as they will come to the surface to breath, but very low oxygen might affect them in terms of the macroinvertebrates that will tolerate that and will serve as food for them (as turtles are carnivorous and tough, they can survive only on bloodworms for example, as this is typical of long necks in polluted streams in Brazil). They are also present in storm water ponds in Canberra with oversaturation of oxygen (full of green filamentous algae) 70 Aquatic_riparian dissolved_oxygen Initial
67 10 0 100 Dissolved oxygen will not matter to most turtles as they can breathe at the surface. Some species are capable of cloacal respiration in the water to varying degrees, but it is debated whether low DO actually affects them negatively, or just forces them to breathe at the surface more frequently. 5 Aquatic_riparian dissolved_oxygen Initial
45 85 75 100 Given they’re both air-breathing mammals, this is more about diversity of food sources as mentioned in previous WQ parameters. 50 Aquatic_riparian dissolved_oxygen Initial
Aggregated 35 25 71 NA 42 Aquatic_riparian dissolved_oxygen Aggregated

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Ammonia Nitrates

When ammonia is present in water at high enough levels, it is difficult for aquatic organisms to sufficiently excrete the toxicant, leading to toxic buildup in internal tissues and blood, and potentially death. This metric seeks to determine the maximum tolerable ammonia levels for the taxon group within suitable habitat.

EDIT: We amended this in a later survey to nitrates When nitrates are present in water at high enough levels, excess nitrogen can cause overstimulation of growth of aquatic plants and algae. Excessive growth of these organisms, in turn, can clog water intakes, use up dissolved oxygen as they decompose, and block light to deeper waters.

The waterwatch CHIP report puts the following nitrate levels as water quality CHIP thresholds (mg/L): Excellent < 1.0; Good 1.0 – 1.3; Fair 1.4 – 1.7; Poor 1.8 – 2.6; Degraded > 2.6

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 0.00 0.00 0.00 I’m unaware of ammonia concentrations in the creeks/dams and how that affect turtles. I put zero due to that. Other people in the panel might know more about it (Ricky?). There is this recent paper on this in China, maybe could be applied here? (https://doi.org/10.1016/j.aquaculture.2021.737302) 5 Aquatic_riparian ammonia Initial
67 0.00 0.00 0.00 See previous comments. This has not been studied. Turtles seem robust to poor water quality based on the environments in which they can be caught (including sewage ponds) 5 Aquatic_riparian ammonia Initial
45 1.00 0.05 2.00 I am not sure of appropriate ammonia levels in waterways as Waterwatch measures nitrates instead. I have entered nitrates measurements here which may not be equivalent. 20 Aquatic_riparian ammonia Initial
Aggregated 0.33 0.02 0.67 NA 10 Aquatic_riparian ammonia Aggregated

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Preferred water velocity

Water velocity relates to the speed at which water flows through aquatic habitats. This metric might influence suitability of habitat for breeding or foraging behaviour for fish and other aquatic species. What is the preferred water velocity for the taxon group within suitable habitat?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 5.0 0 30 I have not measured water velocity before, but I have seen that turtles in creeks/rivers, will prefer the pools, where water velocity is lower. They will do very well in dams/urban ponds, where water is almost ‘stagnant’. So this i a very rough estimate. 50 Aquatic_riparian water_velocity Initial
67 0.0 0 10 I’m going off best guesses here. I’d say turtles prefer slower water, but you can catch them snorkelling in relatively fast water also. Trapping just doesn’t work because the traps are difficult to set in current. 25 Aquatic_riparian water_velocity Initial
45 0.0 0 0 I think both platypus and rakali can handle swimming through high flows . Flood conditions may sweep them downstream and disrupt them temporarily so as long as extreme flows weren’t the norm, it shouldn’t effect them too badly. 50 Aquatic_riparian water_velocity Initial
Aggregated 1.7 0 13 NA 42 Aquatic_riparian water_velocity Aggregated

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Preferred water turbulence

This metric refers to rapid movement of water in several directions at once, like the water movement in a rapid. The turbulence at the air/water interface is where the oxygen gas exchange takes place but high turbulence may prevent species from permanently occurring in a habitat. What is the preferred water velocity for the taxon group within suitable habitat?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 0 0 0 I’m unsure of measuring water turbulance, so I put a zero. As mentioned before, turtles prefer pools and areas with low turbulance, but they could still swim through turbulant waters, but that’s not their ideal habitat. 5 Aquatic_riparian water_turbulence Initial
67 0 0 0 Tubulence might matter, but it has not been examined to my knowledge 1 Aquatic_riparian water_turbulence Initial
45 0 0 0 Again, unless we are talking flood conditions, which we assume aren’t happening all the time, then platypus and rakali can deal with high flows. 50 Aquatic_riparian water_turbulence Initial
Aggregated 0 0 0 NA 19 Aquatic_riparian water_turbulence Aggregated

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Habitat function and risk management

The next series of visualisations relate to habitat function and risk management.

This section asks questions regarding habitat function and risk management for your selected taxon group.

These metrics describe what sorts of risks need to be managed within habitat areas to retain habitat function. The responses to these questions will aid in the identification, design and restoration of habitat patches and connectivity corridors in the urban space, provide an evidence base for policy decision making, and set thresholds for management intervention.

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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Preferred noise levels (during active period)

Anthropomorphic noise may impact on habitat suitability for native fauna by creating disturbance or interrupting communication pathways. This metric seeks to determine the level of anthropomorphic noise preferred by the taxon group. Sources of noise might include commercial or residential areas, traffic, or other human based sources. This metric should be based on the long-term ambient noise level during the day, and exclude short-term sounds, such as cars backfiring in a parking lot. Noises such as school bells, concerts, or sirens would all contribute to the mean noise level.

Decibels: 0 threshold of human hearing, 20 quiet room, 60 busy street, 80 loud radio, 100 subway train, 110 industrial noise, 120 jet plane take-off, 130 gun shot. Remembering that decibels are described on a logarithmic scale.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 60 0.0 100 Noise doesn’t seem to affect turtles, so this is a rough estimate. 30 Aquatic_riparian noise_level Initial
67 0 0.0 20 Again, this has not been studied. Turtles would be most impacted by noise when they are basking. Anecdotally, basking turtles in Australia seem to be very shy, but they acclimate to human presence in well-trafficked areas. How noise affects them directly is unclear. Underwater would be a completely different story. There is some evidence that turtles communicate acoustically, but this is very poorly studied in Australia. 5 Aquatic_riparian noise_level Initial
45 40 20.0 60 I think platypus and rakali get used to noise. They persist in the Queanbeyan river ok next to a busy road and lots of foot traffic. 60 Aquatic_riparian noise_level Initial
Aggregated 33 6.7 60 NA 32 Aquatic_riparian noise_level Aggregated

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Minimum tolerable fire interval

Fire can impact on habitat suitability either by influencing core habitat structural elements (such as ground and mid-storey complexity) or by causing direct mortality to individuals or populations. This metric seeks to determine the minimum tolerable fire interval (assuming low-moderate intensity burns on a patchy sub-hectare scale) before there is an impact on resident species. The assumption is that fire is applied during the active period for the species (e.g. during daylight hours on a warm day for grassland reptiles). We encourage you to leave additional notes around any additional considerations you feel are necessary to support your response.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 0.00 0.00 0.0 I put zero as I am not sure how to respond to this one. While moving on land, or aestivating on land during drought, or eggs in incubation, they might/will all get affected by fire. I might wait until the workshop to re-do this one. 5 Aquatic_riparian fire_interval Initial
67 0.00 0.00 0.0 Fire would only affect nesting areas, or possibly chemical effects of ash on aquatic habitat. Some frequency of fire is probably helpful to turtles to keep nesting areas clear, as long as fires don’t occur during nesting season. Nests are typically ~12 cm underground, so it is possible that they might survive low-intensity fires? 1 Aquatic_riparian fire_interval Initial
45 1.00 0.50 1.5 Not such an issue for platypus sand rakali as they can retreat to their burrows but the ash and sedimentation resulting form fires would have adverse impacts on habitat. 30 Aquatic_riparian fire_interval Initial
Aggregated 0.33 0.17 0.5 NA 12 Aquatic_riparian fire_interval Aggregated

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Minimum tolerable mowing intervals

Mowing can impact on habitat suitability either by influencing core habitat structural elements (such as ground storey complexity) or by causing direct mortality to individuals or populations. This metric seeks to determine the minimum tolerable mowing interval (assuming mowing to 5cm height using a ride-on slasher) before there is an impact on resident species. The assumption is that mowing is undertaken during the active period for the species (e.g. during daylight hours on a warm day for grassland reptiles) and covers all accessible areas (i.e. leaves patches around fence posts and sign bases). It is also assumed that there are limited other ground-layer disturbance mechanisms (e.g. herbivore grazing) taking place in mown areas. We encourage you to leave additional notes around any additional considerations you feel are necessary to support your response.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 3.0 1.00 10.0 In urban areas, mowing a bit before egg laying season and before hatching season (4 months interval) might help turtles to find a suitable nesting spot or hatchlings to move to the wetland once out of the nest (but possibly have a bit of vegetation during nest emergence might help them to avoid predation, if they are very far from the wetland (some females might nest up to 70-100m away from the wetland in some urban ponds). 30 Aquatic_riparian mowing_interval Initial
67 1.0 1.00 1.0 Monthly mowing of nesting areas is probably helpful to keep grass/vegetation low. Turtles will prefer low-veg areas for nesting. 5 Aquatic_riparian mowing_interval Initial
45 0.0 0.00 0.0 I think mowing distances to edge of river would have an impact but not length of time. I may be interpreting this wrong though.. 30 Aquatic_riparian mowing_interval Initial
Aggregated 1.3 0.67 3.7 NA 22 Aquatic_riparian mowing_interval Aggregated

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Minimum tolerable drying interval

Many species depend on accessing standing water to survive or undertake a key part of their life history cycles. Some species may be able to persist without standing water for days, weeks or months, whilst others may not. This metric seeks to determine the maximum period for which a waterbody can be ‘dry’ (no standing water) before there is an impact on the taxon group.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 2.0 0.50 12 There is evidence that turtles can survive on land (aestivation) for more than 1 year. Possibly in urban areas, the access to leaf litter is very important so riparian vegetation is essential. But usually stormwater ponds tend to hold water for longer (due to the increase in flow due to the storm water) compared to a natural creek. 50 Aquatic_riparian drying_interval Initial
67 6.0 0.00 12 This is going to depend on species. Emydura macquarii will not tolerate wetland drying, as they prefer permanent wetlands. Chelodina longicollis almost requires some frequency of wetland drying. They will use permanent wetlands, but often move through the landscape from wetland to wetland. It is possible this is to make use of abundant resources in boom/bust cycles. 5 Aquatic_riparian drying_interval Initial
45 0.0 0.00 0 Both species need water to forage for food and offer protection . Rakali could probably persist opportunistically for a while but both would be very vulnerable. 50 Aquatic_riparian drying_interval Initial
Aggregated 2.7 0.17 8 NA 35 Aquatic_riparian drying_interval Aggregated

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Maximum tolerable presence of introduced predators (incl. fox, dog, cat)

Introduced predators such as cats and foxes are a major source of extinction for native Australian fauna. Domestic dogs are also known to impact on habitat suitability for native species. This metric seeks to determine the maximum number of individual foxes, cats or dogs which can persist in an ecosystem before an impact on habitat suitability is anticipated for other resident species. The metric considers the impacts of both domestic and feral animals combined and will assume ‘individuals’ are separate based on current best practice described in the literature if individual animals cannot be identified from markings alone.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
14 1 0.00 5 One fox can raid several turtle nests, so the less the better. What I did notice that in urban areas, nesting predation is not very high and nests can be found after 2-3 days after laying (in areas with high/moderate fox presence, nests will be predated within the first day of laying). 30 Aquatic_riparian intro_predators Initial
67 0 0.00 5

Foxes have major impacts on turtle nesting. Up to 100% of turtle nests can be destroyed in a given nesting area by a single fox in some circumstances. Foxes also eat adult turtles. These effects are thought by some to be the biggest threat turtles face in south-eastern Australia, but that is still debated to some extent. The data we have suggests that turtle recruitment is very low, and that this is due to foxes destroying nests. We are testing that now using a range of approaches.

On the other hand, there is no evidence that cats affect turtles. They might eat a hatchling if they can get one every now and then, but they have never been reported to dig up a nest or eat an adult turtle. 		100 Aquatic_riparian intro_predators Initial
45 2 1.00 5 would depend on habitat complexity as they could persist in areas with more refugia. 50 Aquatic_riparian intro_predators Initial
Aggregated 1 0.33 5 NA 60 Aquatic_riparian intro_predators Aggregated