Mammals of the Lower Sullivans Creek Catchment, ACT

Prepared by: Christopher R. Tidemann, Toby J. Roscoe School of Resources, Environment and Society, and Beth Mitchell Energy and Sustainability Office (ANUgreen) The Australian National University Canberra, ACT 0200

A report prepared for the Life in the Suburbs project using data from the Lower Sullivans Creek Ecological Survey (LSCCES) September 2006

Summary The Lower Sullivans Creek Catchment is a diverse area that presently supports thirty four species of mammals: two monotremes - both native, nine marsupials - all native, thirteen bats - all native, four rodents - two native, three carnivores – all introduced and two lagomorphs – both introduced (ACT Vertebrate Atlas; C.R. Tidemann, unpublished data). Two bats occasionally recorded from the area have special conservation status: the Grey-headed Flying-fox (Pteropus poliocephalus) is nationally Vulnerable (Environment Protection and Biodiversity Conservation Act 1999) and the Bent-winged Bat (Miniopterus schreibersii) is listed as Rare in the ACT. Several mammals have disappeared from the LSCC following European settlement, including the Koala, (Phascolarctos cinereus) and Tiger Quoll (Dasyurus maculatus). Some introduced mammals are classified as pests, e.g. Foxes (Vulpes vulpes), Rabbits (Oryctolagus cuniculus), and Mice (Mus domesticus).

Introduction Shielding vulnerable species from the detrimental impacts of urbanisation including habitat destruction, fragmentation and simplification, and unnatural selection pressures such as predation and competition from introduced species is essential to the conservation of biodiversity. This enables natural ecological processes to provide the resources required to maintain a healthy mammalian diversity component.

Successfully incorporating the protection of existing ecological communities, creating areas for ecological restoration and implementing integrated, humane and socially acceptable control measures for Invasive Alien Species (IAS) is essential to sustaining healthy populations of mammals in the Lower Sullivans Creek Catchment (LSCC). While statutory regulations currently require development plans to identify and moderate impacts on biodiversity and environment quality, the capacity of such mechanisms to preserve biodiversity assets within urban landscapes is often negligible. In an urban context, the value of these assets is typically underestimated and as such is seldom acknowledged within assessment and planning frameworks.

In addition, the impact of existing developments and their landscapes on biodiversity assets goes largely unchecked despite the potential for these landscapes to harbour serious threats to both local and regional biodiversity, such as IAS. To ensure the

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 2 September 2006 maintenance and enhancement of urban biodiversity, the identification and protection of these assets must be incorporated into development plans as well as mainstream management practices. At present there are few precedents that incorporate such management principles.

This report aims to survey the status of mammals in the LSCC and to highlight management goals to preserve their abundance and diversity within the urban sub- catchment. The analysis provides an assessment of data collected in the LSCC and incorporates knowledge of the site garnered through previous work conducted within the sub-catchment by the authors and by others.

Methodology Prior to the commencement of mapping and permit acquisition, three assessment techniques were proposed: spotlighting, to detect large and particularly arboreal mammals, small mammal trapping using Elliot traps, and sand plots, to capture the tracks of medium sized mammals. Survey design for baseline data collection was limited to spotlighting due to resource requirements and the logistical difficulty of implementing other survey techniques with predominantly volunteer labour. Survey design, protocols and datasheets for mammal spotlighting were adopted from the Great Australian Marsupial NightStalk initiative run through Perth Zoo and the Marsupial Cooperative Research Centre. Protocols were adapted to include provisions for vehicle safety, in addition to tenant privacy in residential and campus zones. Datasheets were adapted to include a list of species likely to occur in the study site, with generic information for each season included to promote standardisation.

Site selection was restricted by the practical difficulties of spotlighting in close proximity to vehicles, with no sites being designated in the Central Business District (CBD). Volunteer safety was also a major consideration in the selection of sites, with areas of dangerous terrain avoided and transects sited predominantly along predefined paths, including cycle paths and walking tracks. Thirteen one kilometre transects were mapped across a diversity of land uses to reflect potential habitat types across the study area. Transects were marked with reflective tape to guide surveyors and ensure consistency of survey transects across seasonal surveys. Map 1 shows the geographic location of transects in relation to infrastructure and landscape components.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 3 September 2006 Map 1. Spotlighting transects

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 4 September 2006

Teams of 2 to 4 people, including one team leader with experience in surveying mammals, surveyed the abundance and diversity of mammals across the thirteen transects, with each team surveying two transects over a one-hour period. Observations were made through visual detection, with notes of macropod movement and bird and bat calls also recorded. Surveys were scheduled to coincide with the new moon in the last month of spring, summer and autumn, with surveys being conducted on the 4th of November 2002, 1st of February 2003 and the 1st of May 2003.

All 13 sites were surveyed in the spring survey, with 12 and 10 sites respectively being completed in the summer and autumn surveys. Lack of experienced surveyors to lead volunteers led to the reduction in sites surveyed in these instances.

Findings Ten mammal species were recorded along spotlight transects in the LSCC. Table 1 highlights these species and includes the thirty-four species known to occur in the study area, their country of origin and their conservation or pest status under Commonwealth and ACT legislation. It is acknowledged that employing only one survey technique, spotlighting, targeted a specific mammal group, being larger mammals. Table 2 indicates the habitat preference of species known to occur in the study site and illustrates the diversity of survey techniques required to comprehensively survey their presence. The use of more sophisticated mammal survey techniques, including sand- trapping and cage-trapping of ground mammals and ultrasound detection of microbats, would provide a more accurate indication of the number of species that use the site. Implementation of these techniques would also help maintain volunteer interest, but would require training of volunteers, ideally through intensive workshops to ensure the accuracy of data and use of appropriate protocols. The implementation of these techniques would require a stable support group of experts to guide survey conduct and to ensure adherence to protocols, particularly with regard to trapping exercises. The cost in human hours and resources to achieve this would be considerable, however, findings would provide a significant contribution to the understanding of urban landscape use by mammals and also in monitoring the success of management actions.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 5 September 2006 Of the mammals recorded in the LSCC, Common Brushtail Possums (Trichosurus vulpecula) and Ringtail Possums (Pseudocheirus peregrinus) are the most abundant native species (Chart 1). The two species are from the same taxonomic family and both are medium sized herbivorous arboreal mammals. To some extent, Brushtail and Ringtail Possums require similar resources from their habitat, though Brushtails were typically more common in built up areas - one would expect this to be the case considering their ability to utilise human dwellings for nesting sites, and to fend off domestic predators such as cats. Ringtail Possums occurred less frequently in built up areas, preferring wooded sites within the study area. Nevertheless, LSCCES data demonstrates that populations of ringtail possums increased sharply between spring 2002 to autumn 2003, while over the same period the population of Common Brushtail Possums declined (Chart 2). This is likely to be a consequence of inter-seasonal behavioural differences between the two species, or may represent a long-term change in the relative abundance of the two species. Severe drought conditions and extensive wildfires in the surrounding region in January 2003 may also have influenced the visibility of Ringtail Possums between the two seasons.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 6 September 2006 Table 1. Mammals recorded from the Lower Sullivans Creek Catchment, showing type, country of origin, conservation status and whether the species was recorded on the survey.

Recorded on Common Name Scientific Name Type Origin Status survey?

House Mouse Mus domesticus Rodent Asia

Gould's Wattled Bat Chalinolobus gouldii Bat

Chocolate Wattled Bat Chalinolobus morio Bat Australia

False Pipistrelle Falsistrellus tasmaniensis Bat Australia

Bent-wing Bat Miniopterus schreibersii Bat Australia Rare

Little Free-tailed Bat Mormopterus planiceps Bat Australia

Lesser Long-eared Bat Nyctophilus geoffroyi Bat Australia

Gould's Long-eared Bat Nyctophilus gouldi Bat Australia

Grey-headed Flying-fox Pteropus poliocephalus Bat Australia Vulnerable

Little Red Flying-fox Pteropus scapulatus Bat Australia

White-striped Mastiff Bat Tadarida australis Bat Australia Yes

Large Forest Bat Vespadelus darlingtoni Bat Australia

King River Bat Vespadelus regulus Bat Australia

Little Forest Bat Vespadelus vulturnus Bat Australia

Agile Antechinus Antechinus agilis Marsupial Australia

Yellow-footed Antechinus Antechinus flavipes Marsupial Australia

Eastern Grey Kangaroo Macropus giganteus Marsupial Australia Yes

Red-necked Wallaby Macropus rufogriseus Marsupial Australia

Sugar Glider Petaurus breviceps Marsupial Australia Yes

Ringtail Possum Pseudocheirus peregrinus Marsupial Australia Yes

Brushtail Possum Trichosurus vulpecula Marsupial Australia Yes

Common Wombat Vombatus ursinus Marsupial Australia

Swamp Wallaby Wallabia bicolor Marsupial Australia Yes

Platypus Ornithorhynchus anatinus Monotreme Australia

Echidna Tachyglossus aculeatus Monotreme Australia Yes

Water Rat Hydromys chrysogaster Rodent Australia Yes

Bush Rat Rattus fuscipes Rodent Australia

Dog Canis familiaris Carnivore Europe Cat Felis catus Carnivore Europe Yes

Red Fox Vulpes vulpes Carnivore Europe Pest

European Hare Lepus europaeus Lagomorph Europe European Rabbit Oryctolagus cuniculus Lagomorph Europe Pest Yes

Black Rat Rattus rattus Rodent Europe Source. ACT Wildlife Atlas and C.R. Tidemann, unpublished.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 7 September 2006 Table 2. Mammals recorded from the Lower Sullivans Creek Catchment showing habitat preferences and preferred survey methods. Spotlighting surveys resulted in only ten species being recorded (shown in bold).

Common Name Scientific Name Habitat Survey Techniques House Mouse Mus domesticus Forest/Woodland/Grassland Trap Gould's Wattled Bat Chalinolobus gouldii Forest/Woodland/Grassland Trap/Ultrasound Chocolate Wattled Bat Chalinolobus morio Forest/Woodland/Grassland Trap/Ultrasound False Pipistrelle Falsistrellus tasmaniensis Forest Trap/Ultrasound Bent-wing Bat Miniopterus schreibersii Forest/Woodland Ultrasound/Cavern Search Little Free-tailed Bat Mormopterus planiceps Forest/Woodland/Grassland Trap/Ultrasound Lesser Long-eared Bat Nyctophilus geoffroyi Forest/Woodland/Grassland Trap/Ultrasound Gould's Long-eared Bat Nyctophilus gouldi Forest Trap/Ultrasound Grey-headed Flying-fox Pteropus poliocephalus Forest/Woodland Night Search/Calls Little Red Flying-fox Pteropus scapulatus Forest/Woodland Night Search/Calls White-striped Mastiff Bat Tadarida australis Forest/Woodland/Grassland Calls Large Forest Bat Vespadelus darlingtoni Forest Trap/Ultrasound King River Bat Vespadelus regulus Forest Trap/Ultrasound Little Forest Bat Vespadelus vulturnus Forest/Woodland Trap/Ultrasound Agile Antechinus Antechinus agilis Forest Trap Yellow-footed Antechinus Antechinus flavipes Forest Trap Eastern Grey Kangaroo Macropus giganteus Forest/Woodland Night Search/Scats Red-necked Wallaby Macropus rufogriseus Forest/Woodland Night Search/Scats Sugar Glider Petaurus breviceps Forest/Woodland Night Search/Calls Ringtail Possum Pseudocheirus peregrinus Forest/Woodland Night Search/Scats/Calls Brushtail Possum Trichosurus vulpecula Forest/Woodland Night Search/Scats/Calls Common Wombat Vombatus ursinus Forest Night Search/Scats/Burrows Swamp Wallaby Wallabia bicolor Forest Night Search/Scats Platypus Ornithorhynchus anatinus Aquatic Day Search Echidna Tachyglossus aculeatus Forest/Woodland/Grassland Diggings/Day Search Water Rat Hydromys chrysogaster Aquatic Trap/Day Search/Spotlight Bush Rat Rattus fuscipes Forest/Aquatic Trap Day/Night Dog Canis familiaris Forest/Woodland/Grassland Search/Scats/Sandplots/Calls Day/Night Cat Felis catus Forest/Woodland/Grassland Search/Scats/Sandplots/Calls Day/Night Red Fox Vulpes vulpes Forest/Woodland/Grassland Search/Scats/Sandplots/Calls European Hare Lepus europaeus Grassland Day/Night Search/Scats European Rabbit Oryctolagus cuniculus Woodland/Grassland Day/Night Search/Scats/Burrows Black Rat Rattus rattus Forest/Woodland/Grassland Trap Source. ACT Wildlife Atlas and C.R. Tidemann, unpublished.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 8 September 2006 Eastern Grey Kangaroos (Macropus giganteus) were the next most abundant native mammal in the LSCC (Chart 1). Their population showed little change between spring 2002 and autumn 2003, with a slight peak in the intervening summer. These large herbivorous ground dwelling mammals roam into irrigated urban areas, especially during long dry periods, leaving the cover of dry sclerophyllous forest, woodlands and grasslands in the surrounding peri-urban reserves in search of fresh plant growth and water. This is the most likely reason for the observed increase in the population of Eastern Grey Kangaroos in the summer months.

Chart 1. Relative abundance of native mammal species recorded on spotlight transects in the LSCC

In comparison to the population indices of the three most abundant species, the abundance of the other native mammal species revealed by the LSCCES are minimal, as are the seasonal fluctuations in their populations (Chart 2). Neither Commonwealth nor ACT legislation considers any of these species threatened or vulnerable at the present time. It is important that the abundance of species with small populations continue to be monitored so that management actions can be taken if decline becomes apparent, and to monitor the impact of actions targeted at increasing their population or distribution.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 9 September 2006

Chart 2. Seasonal native mammal abundance recorded by spotlight transects in the LSCC

Use of greenspace Using indices of mammal diversity and abundance, calculated from the site-specific LSCCES spotlighting data, Chart 3 shows where native mammals were recorded across sites within the LSCC. The data from all seasons and all species have been combined and divided by the number of sampling sessions conducted at each site. This provides a comparative index of mean native mammal abundance and diversity for all transect sites.

These results indicate that sites five (ANBG) and nine (CSIRO) had the greatest native mammal diversity, and sites five and six (ANBG and ANBG extension respectively) the greatest abundance. Sites twelve and thirteen (both located on the Black Mountain Peninsula) had both the lowest abundance and diversity of native mammals. In analysing the spatial distribution of native mammals, we assessed their use of greenspace and vegetation corridors, together with barriers that prevent or inhibit movement and habitat use.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 10 September 2006

Chart 3. Variation in abundance and species diversity between transects

Sites five, nine, six, and eight have a strong combination of abundance and diversity (Chart 3); there is little coincidence that they are all found in close proximity to Black Mountain Nature Reserve (BMNR), which is part of the Canberra Nature Park system. Although BMNR vegetation is predominantly regrowth, it represents the least modified substantial unit of native flora having influence over the LSCC, and must be considered a significant reservoir of both native and invasive mammals.

Conversely, sites two (Acton Peninsula), ten (suburb of Turner), twelve and thirteen (both of Black Mountain Peninsula) exhibit the combination of low diversity and low abundance of native mammals (Chart 3). Sites twelve, thirteen and two are isolated from significant habitat components that may provide ecological resources to mammals (Maps 1 and 2). For example, sites twelve and thirteen are cut off from access to BMNR by the Tuggeranong Parkway, a multi-lane highway, impenetrable to both arboreal and terrestrial mammals due to its width, traffic barriers, walls and volume of fast-moving traffic. In the case of such a structure intervening in the natural movement processes of native mammals, both the structure itself and the behavioural characteristics of the species that encounter it will influence the impact on the mammal abundance and diversity (Hobbs 2005). Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 11 September 2006 Map 2. Vegetation classes within the Lower Sullivans Creek Catchment

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 12 September 2006 Site ten, located in suburban Turner is also isolated from significant vegetation patches despite its proximity to the Sullivans Creek corridor. At this section of the corridor, vegetation is simplified with sparse tree cover and a mown lawn understorey. Mammalian inhabitants along this transect must survive on the suburban vegetation that surrounds them, which consists of mainly coniferous and deciduous exotic trees (Map 2). This vegetation does not provide the resources required by a diverse and abundant population of native mammals, but is able to sustain Common Brushtail Possums (Trichosurus vulpecula) that are capable of foraging solely in the urban landscape and using cavities in buildings instead of tree hollows for shelter and breeding. A single White-striped Mastiff Bat (Tadarida australis) was also sighted along this transect. It is likely that the Bat was flying between adjacent vegetation patches foraging for insects, as the prevailing landscape is unlikely to provide adequate habitat to retain the species on a permanent basis.

There is a continuum of suitability of modified habitat for native mammals (Hobbs 2005), ranging from poorly suitable in highly modified landscapes to ideal in areas that are as close as possible to their native state. Elements of this continuum are represented across the LSCC, and the LSCCES mammal data shows where each site fits (Chart 4).

Chart 4. Correlation between native mammal abundance and diversity in the LSCC

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 13 September 2006 In this hypothesis, benefits of diversity and abundance of vegetation trickle through the ecological web, providing the maximum possible resource benefit to a diverse fauna. Chart 4 illustrates that if there are resources sufficient to maintain an abundant mammal fauna in the LSCC, diversity of native mammal species will be maintained.

Vegetation that supports populations or facilitates movement It is possible to use the data of mammal abundance to form hypotheses about vegetation that either supports populations of mammal species, or acts as corridors, facilitating movement of mammal species from one habitat component of the landscape to another. It is important to note that in order for these hypotheses to form a meaningful part of a conservation strategy they must be routinely reassessed as new data becomes available.

Joining existing habitat fragments is important as it maximises the area available to species that have a large Home Range (HR) requirement. The net primary productivity in the combined HR for any group of mammals must be sufficient and in a form that is accessible in order to sustain the energy requirements of the population. Furthermore, habitat components must be available within the HR to fulfil all other life processes, such as areas suitable for breeding, sleeping, and sheltering from predators.

While vegetation is mapped according to vegetation composition, it is quality and availability of microhabitat components (Bennett 1993) such as nesting hollows, blossoms, fresh foliage, and dense undergrowth, which determine the suitability of an area to small and medium-size mammals. Many of these variables are difficult to quantify, and the relationship between them and native mammals are poorly understood, even after detailed studies within the ACT (Hogg 1990). At this stage there is insufficient data about the occurrence of microhabitat resources in the LSCC to provide a quantitative assessment of their occurrence and benefits, and whilst methodology for its assessment was developed as part of the survey, human resource constraints did not permit its application. The mammal abundance and diversity indices are a proxy for microhabitat data, and therefore areas surrounding transects with a strong mammal component should be managed with sympathy to the requirements of the native mammals in order to preserve diversity.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 14 September 2006 The vegetation types present in the LSCC that are likely to be providing the most benefit to native mammal species by providing resources include: • Native • Casuarina/Native • Native non-Eucalypt • Shrub – native • Herbaceous native/unmown • Native grasses • Reeds

The same vegetation types will facilitate movement of small and medium-size native mammals if corridors of sufficient width and structural diversity are planted and managed appropriately for target species. Positive correlation between diversity and abundance of native mammal species is linked to the complexity and diversity of the vegetation structure, leading to increased microhabitat density (Catling, Burt, and Forrester 2000). This is extremely important in wildlife corridors, as the behaviour of small and medium-sized mammals is focused on predator avoidance, with bottlenecks and the lack of appropriate cover precluding some species (Hogg 1990). In addition, research indicates that invasive animal species use corridors intended for native wildlife mammals (May and Norton 1996), and in so doing may leave scent marks that deter subsequent use by small mammals (Brinkerhoff, Hadden, and Orrock 2005). Far from being any old strip of vegetation, an ideal wildlife corridor is a highly planned and managed habitat component tailor-made to the native mammal species likely to use it, and protected to the extent possible from impacts of IAS and other introduced predators including domestic pets.

Arboreal mammals require continuity in the tree canopy, small terrestrial mammals need constant availability of dense undergrowth, while large native mammals will move long distances in open grassy country, and move under bushes and trees only when resting or chased to cover by a predator. There are no corridors that are large enough or have the integrity and constitution to be suitable for all species of native mammal present in the LSCC, but the Sullivans Creek riparian zone is likely to be the best example. It is the longest patch of vegetation in the LSCC, and although a network of many roads interrupts it, some mammals can use bridges as underpasses where water

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 15 September 2006 levels permit. Consistent with the Griffin plan for Canberra, there is a matrix or web of ‘micro-corridors’ that are highly fragmented by the road system, and as such provide some of the ecosystem functions required for mammal movement and sustenance, but are by no means ideal for use as corridors as animals are exposed to the dangers of road traffic. A network of man-made structures to allow the safe movement of wildlife, such as underpasses and overhead cables, has been suggested to the planning authorities, but such plans are costly to implement and success is not guaranteed (Hogg 1990). The propensity for Common Brushtail Possums and Ringtail Possums to use power and telecommunication lines to move between trees in the urban environment indicates that strategically placed overhead cables may be an effective measure to lower the road-toll of medium-sized arboreal mammals. Smaller mammals are extremely vulnerable to nocturnal raptors in this exposed situation, though potentially no more so than if they are to contend with ground dwelling predators such as cats.

Problems with the LSCC corridor mechanism could be negated to a large degree by the creation of a Sullivans Creek riparian zone corridor along the current flood-zone. Strategic structural enhancement with attention to vegetation composition and microhabitat provision would provide habitat and protection for a diversity of smaller mammal species. Any such plantings would need to be carefully selected and positioned in order to avoid increased risk of flooding and to ensure their retention during high velocity flows. Vegetation patches along the corridor, if large enough, would be particularly beneficial to mammals in dryer periods, particularly if habitat values were to be improved at the northern and southern extremes of the LSCC. Increased structural diversity and density of riparian corridor vegetation would also improve water quality and provide benefits to other biota in the creek. In urban catchments where 24-hour cat curfews and associated monitoring programs are not in place, predation by domestic and stray cats may however limit the success of such strategies.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 16 September 2006 Threats to mammalian diversity As with conservation in wilderness areas, threats to native mammals within urban limits can be attributed to direct human activities and invasive and pest species (both plants and animals) introduced into the landscape. In urban settlements, these impacts are infrequently monitored and typically poorly understood, but can be relatively simple to counteract if the schism between the requirements of humans and native mammals is judged realistically, and steps are taken to ensure development plans and management actions have a maximal benefit to, or minimal impact on native wildlife.

1) Urban habitat resources Habitat destruction, fragmentation and modification are concepts that are usually applied to the negative impact of development in rural areas; however, the same concepts can be used in a holistic conceptualisation of habitat management in the LSCC.

Fundamental to the conservation of native mammals in the LSCC is the preservation of source habitats both within and surrounding the sub-catchment. These areas provide the primary habitat resource for the majority of the mammal species that occur within the sub-catchment. They sustain populations of species that cannot practicably be incorporated into the highly trafficked areas of urban settlements, such as the Eastern Grey Kangaroo, as well as sustaining the core breeding populations of many species that venture into the built environment on a periodic basis such as Echidnas, Sugar Gliders and Bats. A diverse mammalian wildlife component in the LSCC requires source habitat to retain healthy and viable breeding populations. Supplementing the habitat provided by these areas with urban habitat resources and corridors of vegetation that allow movement of species through the urban fabric is the key to ensuring that source habitats do not become isolated from one another and that wildlife does not become relegated to the fringes of our city where the schism between human populations and the natural environment will be enhanced.

Fragmentation occurs when two previously connected stands of vegetation become separated, reducing the potential area available for native animal HR and restricting their movement though the landscape. For example, a large stand of eucalypts, up to 150 stems, some over 20 metres tall, was removed, and an understorey of Acacia and

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 17 September 2006 grasses cleared (J. Berrell pers. com.) for the Burgmann College extension in an area with links to source habitat including BMNR. This area, under two hectares, may not represent a highly valuable habitat component on a large rural property surrounded by bushland, and whilst difficult to quantify retrospectively, it is likely that a broad a diversity of native species including mammals used it. At the scale of this catchment it represented a significant habitat component, contributing to the diversity of mammal and other species within the catchment and providing links from source habitat within the ANBG and adjacent BMNR through the ANU campus and to the Sullivans Creek corridor.

Other site management practices such as pruning decaying branches, removing fallen limbs, and mowing grasses between and around stands of trees and shrubs result in simplification and impoverishment of the vegetation structure. Habitat simplification decreases the suitability of the LSCC as native mammal habitat, and can be counteracted by retaining dead timber and long grass, which will eventually lead to regeneration of a more complex habitat structure conducive to biodiversity enhancement. This is a complicated issue where wildlife abundance and diversity have to be weighed against public liability and development aspirations.

The need to consider public safety and asset protection in urban landscape management often results in aged trees or their limbs being removed where they present a safety hazard or risk to property. Not only do these older trees, especially eucalypts, provide the majority of nesting hollows to native mammals (Tidemann and Flavel 1987), but removal of just one tree or a small group of trees can invalidate the corridor values of the stand by interrupting the continuity of the canopy. A combination of loss of older trees and more exposed movement between landscape components through reduced cover and connectivity will eventually result in a decrease in mammal abundance, diversity and distribution within the LSCC.

While public safety and risk to property are clearly valid considerations, the value of existing habitat ‘stands’ outside of source habitats should receive due consideration in site management, particularly where new development is proposed. The positioning of new developments should be sympathetic to existing habitat features including remnant trees, wildlife corridors, areas of high species diversity and/or

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 18 September 2006 abundance and areas that exhibit rare or diverse microhabitat features, for example, nesting hollows. Nesting hollows are regarded as a limiting resource to the population growth of native mammals and bird species, many of which are dependant upon them for diurnal shelter and breeding sites, and much ecological research has focussed on this aspect of conservation biology (Tidemann and Flavel 1987; Pell and Tidemann, 1997). While providing a sufficient number of hollow bearing trees in the LSCC for the purposes of mammal conservation is impractical as they take up to two centuries to form by natural processes, existing hollow bearing trees and limbs should be retained where risk to public safety can be minimised through diversion of pedestrian access and creation of landscape buffers such as fencing or vegetated landscapes. Management actions can also include natural hollows substitution with nest boxes of the appropriate size, height, and location for access by targeted arboreal mammals.

2) Road traffic One of the greatest impacts on wild mammal populations in urban environments is Road Traffic Accidents (RTAs). For example RTAs in the ACT that involved the death of Eastern Grey Kangaroos showed a sharp rise from 451 in the 1999-2000 financial year, to 1132 in 2001-2002 (Environment ACT 2003). RTAs involving smaller species of native mammals rarely entail damage to the vehicle, and for this reason data regarding these incidences is rarely recorded. It is likely however that RTA’s have a significant impact on their populations in urban areas. It is possible to reduce road-toll of native animals with driver education and warning signs placed in high-risk areas. Eastern Grey Kangaroos are often seen on the verges and road at Clunies Ross Street, between ANU and CSIRO Black Mountain Laboratories in Acton, but the area is not signed as a high-risk environment. Traffic calming measures in other areas of the LSCC frequently used by wildlife could help reduce road-toll of native mammals, but may not be popular with human road users.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 19 September 2006

3) Introduced Alien Species and domestic pets LSCCES transect spotlighting data included two species of introduced mammals, the cat (Felis catus) and the rabbit (Oryctolagus cuniculus), both of which are recognised as IAS and pests to conservation (Short, Turner, and Risebey 2002, and Environment ACT 2003). Chart 5 uses indices to compare their abundance and diversity between LSCCES sites. Cats represent a significant threat to small terrestrial native mammals such as water rats (Hydromys chrysogaster) and will prey on small arboreal mammals opportunistically as they move from one habitat patch to another, this occurs whether the cat is domestic or feral, although it is important that each animal receives a management technique appropriate to its origin. The threats posed by rabbits are competition and habitat destruction through herbivory and burrowing. The former is likely to affect herbivorous native mammals such as Eastern Grey Kangaroo and Swamp Wallaby and inhibit regeneration of native flora; the latter may reduce water quality in Sullivans Creek and through movement of loose soil from burrow complexes by run-off where populations expand unabated.

Chart 5. Abundance and diversity of introduced mammals at LSCCES sites

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 20 September 2006

Under certain circumstances law requires management actions for the control of both feral cats and rabbits; in the LSCC requirements change between Commonwealth and ACT jurisdictions depending on land tenure. Legal requirements should be investigated and where action is required, information regarding these requirements and proposed action plans should be made publicly available to ensure community understanding of the need for the actions and the processes to be undertaken. Action plans should include consultation processes with local ACT government Territory and Municipal Services to ensure actions contribute to wider efforts to control pest species.

Data assessment methods and review of survey methodology It is often impossible to determine absolute figures for mammal populations in a given area of habitat (Catling, Burt and Kooyman 1997), and although the LSCCES covers an area that is relatively small, it is not an exception to this fact. However, indices of abundance and diversity created from various census methodologies can be used effectively to monitor the health of populations through time and assess the effectiveness of management strategies that aim to manipulate them (Caughley 1977 in Engeman et al 2000).

A combination of factors, most notably, the resources available for census methodologies, habitat type, abundance and avoidance behaviour of a particular mammal species determine the bias characteristics of a particular survey methodology. Census by strip transects, including spotlighting, tend to overestimate the abundance of large conspicuous mammals, and underestimate or miss small or inconspicuous species (Sutherland 1996).

In the charts above, indices of abundance and diversity are used. Indices for seasonal abundance are calculated by dividing the total number of species or individuals observed in each season, by the number of instances of observation. The indices given for abundance and diversity at each transect site are calculated by dividing the total number of species and individuals from all three seasons by the total number of observation instances. This simple technique for analysing data will, in the future, enable scrutiny of health of native mammal populations on a yearly basis and identify trends in populations over time, allowing actions to be taken to prevent serious population decline. Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 21 September 2006

If resources are available additional minimally invasive census procedures could be used to investigate the presence of small mammal species likely to be missed by spotlighting. It is not possible to discuss each technique in this report, but Sunderland (1996) and Catling, Burt and Kooyman (1997) critically analyse techniques that may be appropriate to an intensive monitoring effort for native mammals in the LSCC.

In brief, sand plots require no special equipment, but do take time to establish and skill to monitor. With the addition of a scent-post, sand plots may be able to detect the presence of foxes (Vulpes vulpes), which are known to occur in the LSCC and to have a negative impact on biodiversity. Identifying the presence of this species will enable management actions to be determined in a timely manner in consultation with the ACT government to mitigate impacts on native wildlife.

Hair tube techniques would also prove suitable for implementation in the LSCC. Hair tubes do not involve the restraint of native mammals to detect their presence, consisting of simple tubes with adhesive tape on the inside to catch the hair of animals attracted to anchored food baits. Microscopic analysis of the hairs then enables identification of mammals that have visited the tube. This technique is ideal for small mammals that are difficult to spot and identify at night, even with a spotlight.

Bats are another group of native mammals for which spotlighting is inappropriate, as most species are small and fast moving, making them impossible to identify. If resources are available, techniques such as ANABAT, analysis of ultrasonic echolocation calls of microbats, should be employed to detect their presence. ‘Fruit bats’ are vagrant visitors to the LSCC, and detection of their presence is a matter of being in the right place at the right time, monitoring is therefore difficult, but it is important that the habitat resources they are likely to use are protected if diversity is to be maintained.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 22 September 2006 Conclusion A considerable diversity of mammal species is known to inhabit the LSCC, and while spotlighting surveys conducted as part of the LSCC ecological survey revealed less than one third of these species, it is clear that the large “mass” of semi-natural vegetation in the Australian National Botanic Gardens and in the area of CSIRO backing Black Mountain Nature Reserve (BMNR) act as a source habitat within the sub-catchment, with the highest densities and diversity of species being recorded at these sites. This vegetation plays a key role in maintaining populations in adjacent areas, e.g. the Australian National University, as well as providing a significant transition zone between highly populated and developed areas in the inner city and the BMNR, providing a ‘buffer’ between the two land uses. Loss of mammal diversity through removal or modification of any such vegetation should be carefully balanced against development need, as erosion of this habitat is will have significant ramifications for mammal populations in the LSCC.

Very few mammals use the landscapes that border the CBD, with this being potentially the most appropriate outcome – large numbers of kangaroos, for example, do not mix well with motor vehicles; large numbers of Common Brushtail Possums in residential areas can generate problems and complaints to land management agencies, where the lack of appropriate habitat sees them take up residence in houses. Where such conflict exists, a balance needs to be struck between what biodiversity conservation or enhancement is achievable, and what is desirable or practical in a given land use. Balancing these competing demands in an increasingly built-up area is a challenge, particularly given common perceptions that the two goals are mutually exclusive. Attention to this misconception needs to be addressed if community association with urban wildlife is to be positive, with practical examples of working solutions likely to provide the best mechanism to achieve this.

It is clear that considerable mammal diversity does exist in the LSCC– and that strategy can be employed to maintain this diversity; careful planning and community consultation around alternative strategies would be necessary. Maintaining source habitat and movement corridors should be at the core of any such management strategy, however other urban greenspace including the Sullivans Creek corridor and the Black Mountain peninsula can also provide supplementary habitat employing both engineering and landscape design techniques. Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 23 September 2006

Ascertaining management guidelines for the retention of mammal fauna within urban landscapes presents complicated issues, and highlights the need for site-specific analysis in determining an appropriate suite of management actions. Each mammal species has its own specific and highly complex interaction with its environment, at a macro and microhabitat level, and each of these suites of interactions changes between regions, seasons and years, as well as being subject to variations in climatic conditions, such as those associated with El Nino events. The practical and safety limitations of encouraging certain mammal species into the ‘built’ and particularly trafficked areas of urban landscapes also warrant attention. Some species, for example kangaroos, present a significant traffic hazard. Management actions to retain such species may necessarily include provisions to exclude the species from areas where its presence will present a high risk to both the animal and the human residents. In these situations, provisions to retain their presence in nature reserves will provide the most appropriate outcome. Due to these complexities, research conducted elsewhere will not always provide the ‘magic bullet’ solution. This does not mean that goals of sustainable development and biodiversity conservation cannot be met. With the data provided by the LSCC ecological survey, solutions can be tailored for the mammal ecology of the LSCC, catering for site-specific concerns and land-use patterns. The success of such actions will need to be monitored to ensure positive outcomes are achieved, and this process should necessarily include enhancement of survey methodology to capture the best available picture of mammalian population health and diversity across time.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 24 September 2006 References Bennett, A.F. 2003. Microhabitat Use by the Long-nosed Potoroo, Potorous tridactylus, and Other Small Mammals in Remnant Forest Vegetation of South-western Victoria. Wildlife Research 20, 267-285.

Brinkerhoff, R.J., N.M. Hadden, and J.L. Hadden. 2005. Corridors and olfactory predator cues affect small mammal behavior. Journal of Mammology. 86(4), 662-669.

Catling, P.C., R.J. Burt, and R.I. Forrester 2000. Models of the distribution and abundance of ground-dwelling mammals in the eucalypt forest of north-eastern in relation to habitat variables. Wildlife Research 27, 639-654.

Catling, P.C., R.J. Burt and R. Kooyman. 1997. A Comparison of Techniques Used in a Survey of Ground-dwelling and Arboreal Mammals in Forests in North-eastern New South Wales. Wildlife Research 24, 417-423.

Ceballos, Gerardo, Paul R. Ehrlich, Jorge Sobero, Irma Salazar, and John P. Fay. 2005. Global Mammal Conservation: What Must We Manage? Science 309, 603-607.

Engeman, R. M., M.J. Pipas, K.S. Gruver and L. Allen. 2000. Monitoring coyote population changes with a passive activity index. Wildlife Research 27, 553-557.

Environment ACT (2000). State of the Environment Report 2000. http://www.environmentcommissioner.act.gov.au/SoE/SoE2000/ACT/data/nativespecie s/animals.htm#table6

Environment ACT (2003). State of the Environment Report, Indicator: Pest Animals. Environment ACT, Canberra.

Hobbs, R.J. (2005). Landscapes, ecology and wildlife management in highly modified environments – an Australian perspective. Wildlife Research 32, 389-398.

Hogg, D. McC. 1990. The Ecological Resources of the ACT: A Review of Recent Information. Report to the National Capital Planning Authority by David Hogg Pty. Ltd. Environmental Consultants, Macquarie, ACT. Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 25 September 2006

May, S. A. and T.W. Norton 1996. Influence of Fragmentation and Disturbance on the Potential Impact of Feral Predators on Native Fauna in Ausralian Forest Ecosystems. Wildlife Research 23, 387-400.

Pell, A.S. and C.R. Tidemann 1997. The impact of two exotic hollow-nesting birds on two native parrots in savannah and woodland in eastern Australia. Biological Conservation 79: 145-153.

Tidemann, C.R., and Flavel S.C. 1987. Factors Affecting Choice of Diurnal Roost Site by Tree-Hole Bats (Microchiroptera) in South-Eastern Australia. Australian Wildlife Research. 14, 459-473.

Short, J., B. Turner, and D. Riebey. 2002. Control of feral cats for nature conservation. III. Trapping. Wildlife Research. 29, 475-487.

Sutherland, W.J. (Ed.) 1996. Ecological Census Techniques: A Handbook. Cambridge University Press, Melbourne.

Mammal Report for the Lower Sullivans Creek Catchment Ecological Survey 26 September 2006