Introduction

This document summarises the Round 1 - Initial estimates of the Fine Scale Metrics for ACT Urban Habitat and Connectivity Project expert elicitation for small woodland birds 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 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
1 20 1.0 40 rather than more or less being preferred, the key here is variability. Some taxa (Scarlet Robin, Brown Treecreeper, Leaden Flycatcher) forage in and around areas of bare ground, others (Buff-dumped Hornbill, Speckled Warbler, Painted Button Quail) studiously avoid bare areas and gravitate to deep litter beds. So, key point here is to have variety. But, on balance, those open area foragers pretty much all use open areas adjacent to woodlands as well as clearings and bare spots within woodlands, so I’ve gone for less open ground to maximise habitat suitability for all 50 Small_woodland_birds percent_ground Initial
16 20 5.0 40 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. To be honest, I’m not sure how important this metric is for small woodland birds. 50 Small_woodland_birds percent_ground Initial
17 10 5.0 20 Some bare ground or bare ground with very sparse leaf litter can provide food access for seeds, insects for some species birds.
Wondered if bare ground in this question includes sparse/light leaf litter? Or is it completely bare earth, scalded grounds? Answers based on this. Patchiness of ground layer more important, a mix of various density/height grasses, litter, small bare areas etc. 		60 Small_woodland_birds percent_ground Initial
20 10 0.0 40 For finding seed and inverts 80 Small_woodland_birds percent_ground Initial
21 15 5.0 20 Excludes crytogamic crusts, mosses, lichen… 60 Small_woodland_birds percent_ground Initial
Aggregated 15 3.2 32 NA 60 Small_woodland_birds 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
1 25 1.0 50 not that critical for this taxon group. Some species (Diamond Firetails, Buff-ruped and Yellow-rumped Thornbills, Mistletoebirds) favour grass for nest construction, but it’s not a limiting resource. So, given that more % cover grass thatch necessarily = less leaf litter which many species need for daily foraging, I’ve gone for less grass = high habitat quality 50 Small_woodland_birds percent_thatch Initial
16 10 2.0 20 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. However, I’m not very confident with these estimates. 15 Small_woodland_birds percent_thatch Initial
17 10 5.0 20 Educated guess. Extensive dense grass thatch will be limiting factor for some species, eg Brown Treecreeper foraging on ground. For non ground dependent species, not such an issue. May provide some nest opportunities for a few species which nest on or near ground. 60 Small_woodland_birds percent_thatch Initial
20 10 0.0 30 Most grassy systems will have about 10. denser woodlands probably 0. 80 Small_woodland_birds percent_thatch Initial
21 15 0.0 30 Not a common measure of bird habitat - may be valuable for ground-feeding insectivores or cup nesters that collect grass. 20 Small_woodland_birds percent_thatch Initial
Aggregated 14 1.6 30 NA 45 Small_woodland_birds percent_thatch Aggregated

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Preferred depth of grass thatch (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
1 1.0 1.0 5.0 not an issue for any of the small woodland birds 50 Small_woodland_birds thatch_depth Initial
16 5.0 1.0 10.0 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. However, I’m not very confident with these estimates. 15 Small_woodland_birds thatch_depth Initial
17 0.0 0.0 0.0 0 70 Small_woodland_birds thatch_depth Initial
20 0.5 0.0 1.0 Grasslands yes, dense woodlands probably no thatch. 80 Small_woodland_birds thatch_depth Initial
21 3.0 0.0 10.0 Not a common measure of bird habitat - may be valuable for ground-feeding insectivores or cup nesters that collect grass. 10 Small_woodland_birds thatch_depth Initial
Aggregated 1.9 0.4 5.2 NA 45 Small_woodland_birds 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
1 80 40 100 as mentioned in the bare ground section, variability is key here. Larger, deeper litter beds are essential for many ground foraging insectivores, especially during summer when shallow litter gets too hot and dry for invertebrate prey. 75 Small_woodland_birds percent_litter Initial
16 60 30 80 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. Leaf litter is really important for ground-foraging insectivores (e.g. Superb Fairy-wren) as this is where most of their prey species occur. I think this metric is much more relevant than bare ground or grass thatch. I wasn’t sure though - should we be considering if the % cover adds up to 100? 60 Small_woodland_birds percent_litter Initial
17 30 20 40 Guestimate 50 Small_woodland_birds percent_litter Initial
20 20 10 40 Would use the benchmark for woodlands from Phil Gibbons 60 Small_woodland_birds percent_litter Initial
21 40 20 60 Litter known to be a very important feature, esp for the vulnerable woodland bird community 80 Small_woodland_birds percent_litter Initial
Aggregated 46 24 64 NA 65 Small_woodland_birds 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
1 25 15 50 essential food source for just one species (Diamond Firetail relies on active grass seeds) 60 Small_woodland_birds percent_grass Initial
16 20 10 40 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. I wasn’t sure though - should we be considering if the % cover adds up to 100? 30 Small_woodland_birds percent_grass Initial
17 70 50 90 Educated guess. Composition of species important, eg predominately native 60 Small_woodland_birds percent_grass Initial
20 40 10 100 Would use actual data to answer this and many question here. 60 Small_woodland_birds percent_grass Initial
21 60 20 80 Mod-high native grass cover typically associated with high quality woody bird habitat 80 Small_woodland_birds percent_grass Initial
Aggregated 43 21 72 NA 58 Small_woodland_birds percent_grass Aggregated

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Preferred % invasive grass cover (e.g. Wild oats, Chilean Needle Grass, Serrated Tussock, African Love Grass)

It is possible/likely that a component of total grass cover in the urban space will be comprised of highly invasive grass species. These species can monopolise grassy areas and impact on ground layer structure and function for many species. What is the percentage cover of invasive grasses which is consistent with preferred habitat for this taxon group? This metric might be used to trigger invasive plant management regimes, or identify priority areas for restoration, as some examples.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
1 10 1.0 25 some work (Grace Tame’s PhD in Adelaide) found Diamond Firetails do include exotic grass seed in their diet, but natives preferred and of higher nutritional quality). All other small woodland birds only need grass for cover / nesting material and I’m not aware of any work evaluating role of native versus exotic species 45 Small_woodland_birds percent_invasive Initial
16 0 0.0 10 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. However, I’m not very confident with these estimates. 20 Small_woodland_birds percent_invasive Initial
17 10 0.0 50 0 50 Small_woodland_birds percent_invasive Initial
20 15 0.0 80 Probably only a noticeable impact where smothers out bare ground and diversity. 70 Small_woodland_birds percent_invasive Initial
21 25 0.0 50 Exotic grasses can still provide valuable structure and foraging substrate 50 Small_woodland_birds percent_invasive Initial
Aggregated 12 0.2 43 NA 47 Small_woodland_birds percent_invasive Aggregated

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Preferred % exotic broad leaf cover (e.g. thistles)

Exotic broad leaf plant species (such as thistles or pigweed) make up the majority of the non-native ground layer plants which are not grasses, sedges or rushes. They may exclude native vegetation from growing in the ground layer or alter habitat structure. What percentage cover of exotic broad leaf plants is consistent with preferred habitat for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
1 30.0 20 40 no published work on this, but worth considering microclimatic factors: increased broad-leaf cover, including by exotic plants, will provide more humid and shaded microhabitats, increasingly needed by small birds that struggle to regulate their temperatures when ambient temperatures exceed body temps (38 to 42 degrees). Again, as with grass and bare ground and litter, variability is key, and ideally, multiple small patches of almost pure broad leaf beneath tree canopies would give the greatest microclimatic amelioration 50 Small_woodland_birds percent_broad Initial
16 0.0 0 5 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. However, I’m not very confident with these estimates. 20 Small_woodland_birds percent_broad Initial
17 1.0 0 10 Not sure on this one 50 Small_woodland_birds percent_broad Initial
20 15.0 0 70 Can provide food, probably resilient to most levels. 70 Small_woodland_birds percent_broad Initial
21 0.0 0 30 Not confident on this one 10 Small_woodland_birds percent_broad Initial
Aggregated 9.2 4 31 NA 40 Small_woodland_birds percent_broad 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
1 250 100 500 my best estimate of 250 equates to 25 slender fallen trees or a dozen larger fallen trees. rather than length, though some work by Terry Korodaj (CSU Honours) demonstrated that degree of decomposition and size are critical, bigger and more decomposed the better 50 Small_woodland_birds cwd_length Initial
16 15 3 20 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. 30 Small_woodland_birds cwd_length Initial
17 100 50 200 Do not understand this metric/measure, not sure of relevance using length, and may be difficult to assess. Number of small, medium, large logs, stags, stumps etc more meaningful and easier to count? Based best estimate on 50 x 2 metre logs, possibly conservative. 60 Small_woodland_birds cwd_length Initial
20 300 0 1000 This is benchmark for grassy woodlands. 80 Small_woodland_birds cwd_length Initial
21 40 10 80 Highly valuable resource, arrangement and decomposition state likely important in addition to total length 50 Small_woodland_birds cwd_length Initial
Aggregated 141 33 360 NA 54 Small_woodland_birds cwd_length Aggregated

Preferred number of hollow bearing trees

A hollow-bearing tree is a tree where the trunk or limbs contain hollows, holes or cavities. Hollows are particularly important for providing shelter and nesting sites for fauna, with some species being hollow dependant. What is the preferred number of hollow bearing trees required for the habitat to be suitable for this taxon group? Consider the minimum number of hollow bearing trees in a one-hectare patch.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
1 10.0 2.0 20 as well as number of hollow bearing trees, variation in hollow size is critical, both in terms of providing resources for more species as well as giving animals options to select hollows with preferred aspect / height / microclimate 40 Small_woodland_birds no_hbtrees Initial
16 4.0 1.0 5 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. This will be particularly important for Striated Pardalotes and Brown Treecreepers. I assume we are referring to hollow-bearing trees where hollows are the right size for these species? Any larger hollows will likely be monopolised by parrots or possums. 40 Small_woodland_birds no_hbtrees Initial
17 20.0 10.0 25 Number of small, medium or large hollows may also be meaningful measure for birds community. Tree species may determine the no/density of hollows. 60 Small_woodland_birds no_hbtrees Initial
20 5.0 0.0 100

Must be a benchmark.

https://www.sciencedirect.com/science/article/abs/pii/S0378112705005001

https://www.sciencedirect.com/science/article/abs/pii/S0006320708002632

https://www.sciencedirect.com/science/article/abs/pii/S0378112711001551 		30 Small_woodland_birds no_hbtrees Initial
21 3.0 1.0 6 Estimate assumes hollow bearing tree is also large & mature tree (not always the case) 80 Small_woodland_birds no_hbtrees Initial
Aggregated 8.4 2.8 31 NA 50 Small_woodland_birds no_hbtrees Aggregated

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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
1 40 25 100 hmm, very tricky to distil all this complexity down to a single figure. Suggest particular resources are going to be more influential–eg, numbers of mistletoe per hectare will give a realistic estimate of how much nectar will be available, especially during summer when little else is in flower. Also note that, when nectar availability reduces, birds will leave. Nectarivores have been doing this for millions of years, tracking areas with more flowers / higher fractions of carbohydrates often over large distances. 40 Small_woodland_birds percent_floral Initial
16 40 20 60 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. To be honest, I find this difficult to estimate as flowering resources will vary enormously between different plant groups and strata. 30 Small_woodland_birds percent_floral Initial
17 15 10 20 A guess on this one. 50 Small_woodland_birds percent_floral Initial
20 30 0 50

Don’t really get this question.

This info would be better extracted by measuring at high woodland bird locations. 		1 Small_woodland_birds percent_floral Initial
21 5 0 50 This is really complicated. My ‘best estimate’ reflects the likely scenario of using these estimates to conserve predominantly resident and vulnerable woodland birds in CNP or ACT urban greenspace. 50 Small_woodland_birds percent_floral Initial
Aggregated 26 11 56 NA 34 Small_woodland_birds 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
1 15 5 25 again, diversity is a bit of a blunt measure here. Mass flowering eucalypts are by far the most important nectar resource in terms of sheer volume, but also need to consider phenology and seasonal pinch points. Ornamentals (both natives from elsewhere and exotics) as well as mistletoe are very important sources of nectar when eucs are not flowering 40 Small_woodland_birds min_flower_sp Initial
16 15 5 30 This is outside the scope of my experience. I am not a botanist and cannot comment on the number of different flowering plant species within a habitat patch. 5 Small_woodland_birds min_flower_sp Initial
17 25 10 50

An educated guess, but: low estimate based on 1-3 eucalypt, 1 mistletoe, several wattle/other shrub

upper estimate, more is better, could be higher

best estimate based on 3-4 eucalypt species, 1 mistletoe, 4-6 wattles, and range smaller nectar bearing shrubs/plants such as peas, heath, correa, grevillea, dianella

No of bird species occurring would be related to number and species flowering 		60 Small_woodland_birds min_flower_sp Initial
20 50 5 100 This is not scale floristics is measured at. 80 Small_woodland_birds min_flower_sp Initial
21 0 0 0 I don’t think this is important 1 Small_woodland_birds min_flower_sp Initial
Aggregated 21 5 41 NA 37 Small_woodland_birds 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
1 4 2 8 comments as for previous question 40 Small_woodland_birds temp_floral Initial
16 6 3 12 I find this one tricky, as species will move around following flowering resources. I think the broader landscape, or landscape context, plays an important role here which is not being captured in this question. If a patch of habitat is without flowering resources for x months of the year, but birds can safely move to another patch to utilise those resources, then the species can still persist in the landscape. As such, I’m not very confident with these estimates. 20 Small_woodland_birds temp_floral Initial
17 6 4 12 An educated guess. Specific months/season when flowering occurs would be relevant factor for small woodland birds, spring breeding season for birds important, also food resources in winter months 60 Small_woodland_birds temp_floral Initial
20 9 6 12 Probably best looking at life history of plants in a good quality area. 50 Small_woodland_birds temp_floral Initial
21 20 0 100 Again, really complicated. My ‘best estimate’ reflects the likely scenario of using these estimates to conserve predominantly resident and vulnerable woodland birds in CNP or ACT urban greenspace. 10 Small_woodland_birds temp_floral Initial
Aggregated 9 3 29 NA 36 Small_woodland_birds temp_floral Aggregated

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Preferred number of mistletoes

Mistletoes are semi-parasitic plants that grow on a host tree or shrub. Mistletoe provides a keystone resource providing structural and nutritional resources within canopies for woodland dependant species. What is the minimum number of mistletoe plants in an area for the habitat to be preferred by this taxon group? Consider the preferred number of mistletoe plants in a one-hectare patch.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
1 8 2.0 20 Relevant research is available here, looking at bird occurrence relative to mistletoe availability–one of few ‘best estimates’ I’m actually confident about! 80 Small_woodland_birds no_mistletoe Initial
16 5 1.0 20 Again this is outside the scope of my experience. I have never recorded the occurrence of mistletoe so I can’t be sure of these estimates. 10 Small_woodland_birds no_mistletoe Initial
17 12 6.0 20 based this on experience with local woodland bird monitoring sites using habitat complexity scores for attributes such as mistletoes; generally 6- 20 mistletoes in a .8 hectare plot is Ok/optimum (high quality sites). Too many mistletoes can be negative for tree health. 70 Small_woodland_birds no_mistletoe Initial
20 100 10.0 500 Depends on tree density and size classes. 60 Small_woodland_birds no_mistletoe Initial
21 30 5.0 100 See research by Dave Watson - well known that mistletoe highly beneficial to woody bird communities through multitude of functions - up to 200 plants / ha can be sustained in natural environs. 50 Small_woodland_birds no_mistletoe Initial
Aggregated 31 4.8 132 NA 54 Small_woodland_birds no_mistletoe Aggregated

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Preferred % cover of shrub layer (0.5-3m height)

The mid-storey or shrub layer provides structure for nesting, refugia from predators and food resources for many species. This could be related to the amount or complexity of structure the species group prefers or is tolerant of in its preferred habitat, or some other feature of the species groups’ general biology or life history. This metric considers the percentage cover across a one hectare patch.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
1 15 5 50 variability is key. So, some shrubs, but not scattered, clumped, especially in gulleys and break-of-slope landforms 50 Small_woodland_birds percent_shrub Initial
16 40 20 50 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. I also looked over site-level habitat data from my 1,500 PhD sites. 60 Small_woodland_birds percent_shrub Initial
17 30 20 50 Educated guess, based on grassy woodland of medium density, with 30% shrub cover max/optimum for grassy woodland community 60 Small_woodland_birds percent_shrub Initial
20 20 0 90 Depends on bird. 60 Small_woodland_birds percent_shrub Initial
21 15 5 30 Complexity without high density seems key 50 Small_woodland_birds percent_shrub Initial
Aggregated 24 10 54 NA 56 Small_woodland_birds percent_shrub 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
1 40 20 60 more trees might seem necessarily better but, although this group does include some forest species that inhabit dense habitats, many prefer a more open structure 50 Small_woodland_birds percent_canopy Initial
16 40 20 50 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and looked over site photos. I also looked over site-level habitat data from my 1,500 PhD sites. 70 Small_woodland_birds percent_canopy Initial
17 40 30 50 Guesstimate? 50 Small_woodland_birds percent_canopy Initial
20 30 0 80 Would use existing benchmarks. 80 Small_woodland_birds percent_canopy Initial
21 20 10 30 Open structure standard for high quality woodland to support birds 80 Small_woodland_birds percent_canopy Initial
Aggregated 34 16 54 NA 66 Small_woodland_birds percent_canopy 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
1 20 1.0 50 not aware of any work on this 30 Small_woodland_birds noise_level Initial
16 0 0.0 40 To derive my estimates, I drew on prior experience conducting bird surveys in remnant woodland habitats and my memory and notes of site-level noise during these surveys. I have assumed that the level of noise we are estimating here is anthropogenic/urban noise, rather than all possible noise (e.g. wind, other species). 40 Small_woodland_birds noise_level Initial
17 0 0.0 0 Do not have knowledge/expertise to give meaningful answer. Not aware of relevant research. 1 Small_woodland_birds noise_level Initial
20 20 0.0 40 Have to assume quiet given calls. 80 Small_woodland_birds noise_level Initial
21 0 0.0 60 Only familiar with effects of noise on song volume, not site occupancy. 10 Small_woodland_birds noise_level Initial
Aggregated 8 0.2 38 NA 32 Small_woodland_birds 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
1 300 120 600 not sure 25 Small_woodland_birds fire_interval Initial
16 60 36 84 This is outside the scope of my expertise. I have no knowledge or experience in fire ecology and don’t feel comfortable advising on this metric. I would suggest you contact an expert in this field, such as Prof. Michael Clarke at La Trobe University. 5 Small_woodland_birds fire_interval Initial
17 0 0 0 Do not have expertise in this field and would be guessing. 1 Small_woodland_birds fire_interval Initial
20 240 36 500 Depends if wild fire or cool burn or hazard reduction. My answer is hazard reduction/wild fire 80 Small_woodland_birds fire_interval Initial
21 60 24 120 Really not my area, but there should be decent work around this 10 Small_woodland_birds fire_interval Initial
Aggregated 132 43 261 NA 24 Small_woodland_birds 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
1 12.0 2.0 24 not sure 25 Small_woodland_birds mowing_interval Initial
16 12.0 6.0 36 This will be dependent on the growth rate of different understorey species. I’m not familiar with current mowing regimes or expected growth rates, so this is difficult to estimate with any certainty. 15 Small_woodland_birds mowing_interval Initial
17 12.0 9.0 12 Do not have knowledge to give meaningful answer. But would be a factor for some bird species and more frequent mowing would reduce species diversity. 40 Small_woodland_birds mowing_interval Initial
20 6.0 2.0 24 No real upper. 60 Small_woodland_birds mowing_interval Initial
21 0.0 0.0 0 I don’t mowing is important 1 Small_woodland_birds mowing_interval Initial
Aggregated 8.4 3.8 19 NA 28 Small_woodland_birds mowing_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. Unit of measurement as number of individual introduced predators in a 24-hour camera trapping period.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
1 1.0 0.0 8.0 tricky 30 Small_woodland_birds intro_predators Initial
16 2.0 1.0 6.0 This one is also really challenging. I feel very confident about the minimum value (1 cat or fox), but not at all confident about the maximum and best estimates. Surely this depends on the size of the habitat patch? Are we assuming this is a core habitat patch from our previous discussions? I feel I’m missing some information. 20 Small_woodland_birds intro_predators Initial
17 0.0 0.0 0.0 Do not have expertise in this field to give meaningful answer. Cats, other introduced predators are regarded as a negative factor generally for birds, esp small bird populations in fragmented landscapes, can suppress small bird populations 1 Small_woodland_birds intro_predators Initial
20 0.0 0.0 1.0 Confused. 1 detection per 24 sounds high based on my experience. 1 per week would be average I thought. 50 Small_woodland_birds intro_predators Initial
21 0.0 0.0 1.0 every predator you smoke is doing you damage…“” 10 Small_woodland_birds intro_predators Initial
Aggregated 0.6 0.2 3.2 NA 22 Small_woodland_birds intro_predators Aggregated

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Maximum tolerable presence avian competitors/aggressive bird presence (noisy miner, common myna)

Aggressive birds can reduce the suitability of habitat for woodland birds in particular due to aggressive interactions and competition for limited resources. This metric seeks to determine the maximum number of Noisy Miner and Common Myna birds (combined) which can be detected before an impact on habitat suitability is anticipated for other resident species. Unit of measurement is the number of aggressive birds detected in a standard 20-minute point count survey.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
1 2 1 3 Very low numbers indicate the area is not a territory where miners reside. The odd one =. a passing individual, but any more than that and it means they’re resident and will beat up all the little hobbies 50 Small_woodland_birds avian_presence Initial
16 10 5 30 To derive my estimates, I drew on prior experience conducting bird surveys where Noisy Miners and/or Common Mynahs were present. From what I have witnessed, Noisy Miners are far more aggressive and more successful at driving off small woodland birds than Common Mynahs. Small woodland birds and Common Mynahs are also less likely to cross paths due to different habitat preferences. My PhD data suggests that landscape-level community composition is strongly influenced by the reporting rate of Noisy Miners, however, I don’t have concrete data on the number of Noisy Miners required to influence small woodland birds at the site-level. I would suggest speaking to an expert in this field, such as Prof. Michael Clarke from La Trobe University. 50 Small_woodland_birds avian_presence Initial
17 1 1 1

Per hectare density of populations of these species may be better measure. There has been research on Noisy Miners, .6 birds per hectare is established threshold, shown to have negative effect on small birds populations, be an indicator of a problem. I dont have access to references. There are other indicators, such as urban context, landscape topography, which may have influence.

Could not specify .6 in answer, minimum it allows is 1 		70 Small_woodland_birds avian_presence Initial
20 1 0 20

ACT use 10 min 50m radius counts. Think you are referring to 20 min 2 ha count above.

I would use quantitative data here not expert opinion. 		60 Small_woodland_birds avian_presence Initial
21 6 3 12 Would help to know survey area covered in 20 minutes. My estimates are made primarily with noisy miner in mind. Many species are highly tolerant of common myna and their distribution is much more restricted in woodland patches. 50 Small_woodland_birds avian_presence Initial
Aggregated 4 2 13 NA 56 Small_woodland_birds avian_presence Aggregated

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