Threats to Biodiversity

The most common and problematic weeds within the region range from trees, such as Sweet Pittosporum (Pittosporum undulatum), Desert Ash (Fraxinus angustifolius), Willows (Salix sp)Olive (Olea europaea), Pine (Pinus radiata), and shrubby, woody weeds including Gorse (Ulex europaeus), Montpellier Broom (Genista monspessulana), Erica (Erica sp.), Pampas Grass (Cortaderia sp), Boneseed (Chrysanthemoides monilifera) and Blackberry (Rubus fruticosus), to grassy, herbaceous and creeping exotics such as Blue Periwinkle (Vinca minor), Rice Millet (Piptatherum miliaceum), Phalaris (Phalaris aquatica) and Bulbil Watonia (Watsonia meriana ssp. bulbifera).

Weeds have been categorised to reflect factors such as invasiveness, potential to spread, 'perceived' and 'actual' impacts and their environmental, economic and social impact. Some of the more common and emerging plants known from the Adelaide Hills Council district fall into one or more of the listed categories.

If you suspect that you have discovered a Declared or Weed of National Significance (WoNS) on your land, please contact the Landscapes Hills and Fleurieu or if on a or roadside or Council Reserve, contact Council for identification and management advice.

For information to help manage invasive weeds, visit the Weeds Australia website via the link below.

For alternative common and scientific names for all plants prohibited from sale in South Australia, and a free Weed Control app, which provides information about the control of weeds declared in South Australia, please visit Primary Industries and Regional SA (PIRSA) Biosecurity SA Division website via the link below.

• Death or deterioration of health of susceptible plant species (eg. Eucalyptus obliqua (Messmate Stringybark), Eucalyptus baxteri (Brown Stringybark), Xanthorrhoea sp. (Yacca), Banksia sp. (Banksia), Isopogon ceratophyllus (Conebush), Leptospermum sp. (Tea Tree), Acacia myrtifolia (Myrtle Wattle), Pultenaea involucrata (Mount Lofty Bush-pea), Acrotriche fasciculiflora (Pink Ground-berry) and species from Fabaceaea (Pea family).
• Diseased plants with general discolouration of foliage, usually red or yellow foliage.
• Phytophthora resistant species remain unaffected.
• Progression of deaths over time, particularly down slope and an obvious boundary may be apparent between diseased and healthy areas.

• Avoid areas of known Phytophthora infestations.
• Stay on designated roads and tracks.
• Obey road signs indicating restricted areas associated with Phytophthora infestation.
• After entering or working in areas of infestation, clean soils from footwear (and/or horses hooves) with a stiff brush and spray with undiluted methylated spirits (see Hygiene procedures table below).
• Using hygiene stations on tracks/trails where provided.
• Clean machinery and equipment and other tools appropriately before using in other areas.
• Undertake works in Phytophthora infested areas when conditions are driest (avoid winter months).
• If infestation areas are known, use machinery in areas that are un-infested first, moving to infested areas last, following up with appropriate hygiene measures.
• Avoid excavating in infested areas.

(source: Phytophthora Technical Group (2006) Phytophthora Management Guidelines)

Since their introduction in the mid-1800s, foxes have had a devastating effect on native species of mammals, birds and reptiles across the region, contributing to the extinction of almost 30 native mammals from mainland South Australia. In conjunction with widespread loss of habitat across the region, foxes place further pressure on remaining native populations, including threatened species such as the Southern Brown Bandicoot, Yellow-footed Antechinus, Cunningham's Skink and the Common Brushtail Possum. They are also known to kill lambs and poultry.

Landholders are responsible for the control of foxes on their properties under the Landscape South Australia Act 2019. Many landholders are actively managing foxes on their private properties, whilst others have undertake a coordinated approach with volunteer groups and organisations such as the Hills and Fleurieu Landscape Board. Overall the management across Council land is somewhat 'ad hoc', with sporadic management undertaken by the Hills and Fleurieu Landscape Board in consultation with Council. In many cases, the risk of off–target poisoning to domestic dogs, is too great and therefore the AHC do not endorse the use of baits within their reserves.

FoxScan is a community website that allows you to record and map sightings of foxes, fox damage, and control activities in your local area. Use FoxScan data recorded in your region to help decide where to undertake control, and coordinate with your neighbours. Find the link below.

Rabbits were introduced to Australia soon after European settlement. Their numbers rapidly exploded causing huge impacts to biodiversity and agriculture. They compete with native animals for food resources, damaging crops and native plants by ringbarking trees and shrubs, inhibiting regeneration by eating seed and seedlings. Their warrens can also cause soil destabilisation and erosion. Competition and land degradation by rabbits is listed as a key threatening process under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.

Wetter conditions combined with milder summers in recent years have contributed to an increase in rabbit populations across the Adelaide Hills. For advice regarding management of declared pests, contact the Hills and Fleurieu Landscape Board - Mt Barker. Method, timing, placement and exclusions may all need to be considered for rabbit control in your specific situation to maximise effect and prevent off target damage or to ensure the baits are actually taken by rabbits rather than off-target species.

Since the release of Myxoma Virus and Rabbit Calicivirus Disease (RCD), overall rabbit numbers have significantly reduced. However, rabbits developed resistance to Myxomatosis and are also predicted to become resistant to RHDV. Currently their numbers still fluctuate in response to seasonal conditions and other management tools being used by landholders to control populations, including poisoning, shooting and warren destruction. These are suitable methods in rural settings, however controlling rabbits in urban and bushland areas can be problematic. Removing available refuge (rubbish, woodpiles etc) and destroying warrens can help to reduce rabbits.

In December 2023, the Landscapes H&F held regionally coordinated rabbit control program information sessions, followed by Pindone and K5 Calicivirus distribution days for private landowners and Councils to collect treated carrots at six pickup locations. Baits are generally made available over summer, the exact dates depend on weather conditions, but it’s usually early-mid December. Following Autumn rains, green feed becomes abundant and the optimal time to lay baits has ended.

RHDV1 or K5, or the Calicivirus Korean strain of Rabbit Haemorrhagic Disease Virus, was released in 2017. This was used at 45 sites across South Australia and data from 16 sites showed a 50% decrease in rabbit numbers. In 2019, PIRSA Biosecurity released K5 at 4 locations in the Mt Lofty Ranges including the Central Hills. Further releases occurred in 2022, 2023 and 2024, with Council undertaking K5 release at 6 sites across the region.

In 2025, Council intends to extend this program to include 8-10 reserves generally spread across the district, focusing on reserves where rabbits are regularly observed.

• Woorabinda Bushland reserves, Stirling
• Lobethal Bushland Park
• Candlebark Reserve, Aldgate
• Mylor Oval
• Mylor Parklands
• The Deanery, Bridgewater
• Kersbrook Conservation Reserve
• Sunnyspring Reserve, Aldgate
• AL Vincent Reserve, Bridgewater

Calicivirus (RHDV) K5 only impacts Rabbits and Hares, a safe control method in residential and bushland areas as it poses no threat to humans, domestic animals such as dogs, or native animals (bandicoots, possums, kangaroos and birds). Domestic rabbits are at risk from the virus, so unless they are kept inside and away from insects, they need to be vaccinated.

Council does not participate in a rabbit Pindone baiting programs, as it is not able to use it safely in line with label requirements and cannot ensure the safety of native animals, dogs and unattended children. Instead, Council collaborates in annual warren fumigation, K5 releases and biocontrol initiatives with the Landscape Board.

Please report any rabbit sightings or activity (warrens, damage, and control activities) via RabbitScan to assist the development of regional rabbit control programs.

Contacts and useful links -
Hills and Fleurieu Landscape Board - Mt Barker (08) 8391 7500 | Rabbit Control Advice
PIRSA Biosecurity SA | (08) 8303 9620
K5 Vaccination information for domestic rabbit
Controlling Rabbits in Urban Areas Factsheet — Copyright Department of Environment, Water and Natural Resource

Deer were first introduced into Australia in the 1800s as game animals. Within the Mount Lofty Ranges region, some Fallow and Red Deer have escaped from commercial farming properties or been released, resulting in a widespread increasing population of ‘feral’ deer.

There are six species of feral deer across Australia, however the main pest species in South Australia is the Fallow deer and the Red Deer. The current population estimates are approximately 4,000 in the State, 8,000 in Hills and Fleurieu region, 1,500 in Green Adelaide and a further 2,000 in peri-urban settings.

Impacts caused by deer include damage to native vegetation and commercial crops and pastures, and more recently residential gardens in peri-urban settings. More specifically the impacts are causing overgrazing, browsing, trampling, ring-barking, dispersal of weeds and spreading disease such Phytophthora, damage to fences, creation of trails through bushland and acceleration of erosion.

Currently Hills and Fleurieu Landscape Board is undertaking a range of investigations and compliance measures to identify the distribution, impacts and potential options for controlling Fallow Deer which have escaped from commercial properties. The State and region are working towards eradication of the species in a 10-year timeframe under the recently developed Strategic Plan for the South Australian Feral Deer Eradication Program 2022-2032.

Under the Landscapes Act 2019, 'feral' deer are a Declared species, and it is the landholder's responsibility to satisfactory control feral deer on their properties. It is also a deer keeper's responsibility to notify neighbouring landowners and the Hills and Fleurieu Landscape Board of escaped farmed deer.

Any sightings of feral deer should be reported to Hills and Fleurieu Landscape Board where landowners can also obtain advice about control measures.

Contacts and useful links

PIRSA Biosecurity SA — (08) 8303 9620

Deer reporting website and smartphone app

FeralDeerScan is a free community resource for landholders, community groups and pest controllers. DeerScan can be used to map sightings, report problems or damage caused by deer, and document control actions. It can be used to inform your neighbours and local biosecurity authorities about current deer problems. You can use DeerScan to record new (and historical) observations of deer in your local area, as this will help to build a detailed picture of deer populations.

Useful links

Fallow Deer Pest Management Guide

Goats arrived in Australia with the settlement of the colonies by the first Europeans. Descending from those that escaped, the feral population has spread across Australia, causing significant economic and environmental damage through overgrazing and competition with livestock and native herbivores. Goats are known to trample, heavily browse and ring-bark native and planted vegetation, cause erosion, spread weeds and leave strong odours around their camps, driving away some native species.

Currently goats are actively monitored and removed in some National Parks and Wildlife reserves with methods such as satellite tracking, trapping and shooting, with collaboration between numerous stakeholders.

Council does not currently manage goats on Council land due to the high risk posed to public safety associated with some of these methods.

Under South Australia’s Landscapes Act, 2019, feral’ goats are a declared animal and it is the landholder’s responsibility to control them on their properties. It is also the responsibility of landowners who keep goats to notify neighbouring landowners of any escaped animals.

Any sightings of feral goats should be reported to the Hills and Fleurieu Landscape Board, where landowners can also obtain advice about control measures.

Contacts and useful links

PIRSA Biosecurity SA — (08) 8303 9620

Goat reporting website and smartphone app

FeralGoatScan is a community website that allows you to record and map sightings of feral goats, damage, and control activities in your local area. Use data to identify priority areas for feral goat control, and work with your local land managers to implement control in a coordinated approach.

Feral cats are defined as those that live independent of humans and survive by hunting or scavenging. Introduced early during European settlement, feral cat colonies became established in the wild by the 1850s. Feral cats have spread from domestic populations, either as abandoned animals or intentionally released to help manage rats and mice.

Feral cats impact significantly on Australia's biodiversity, predating on many native species, especially birds, reptiles, amphibians and small mammals. Between the foxes and feral cats, their combined impacts have led to the extinction of almost 30 native mammals from mainland South Australia and continue to threaten many more².

In 2015 a Threat Abatement Plan for predation by feral cats set out a national framework to guide and coordinate Australia's response to the impacts of feral cats on biodiversity. It identified research, management and other actions needed to ensure long-term survival of native species and ecological communities affected by this issue.

Council's Cats By-law 2018 (By-law No. 6) was created to control and manage cats in the Council area. Under this by-law, cats must be confined to their resident's premises unless under effective control by a leash or similar restraint. This helps limit the impacts to native fauna through predation and allows Council staff and volunteers to separate out feral cat populations from domestic pets to facilitate feral cat management. Council also revised it's Animal Management Plan in 2018.

Feral cat reporting website and smartphone App

FeralCatScan is a new project by the Invasive Animals CRC and Australian Government Department of the Environment, and is supported by communities Australia-wide to improve knowledge about feral cats to help protect Australia's threatened wildlife.

Information sources

¹ Copyright, Department of Environment, Water and Natural Resources (2015) Deer pest management guide — Fallow Deer (Dama dama)
² Natural Resources Management (NRM) board — Animal Pests of South Australia Factsheet

¹ West, A. (2016) Climate Change and Biodiversity Landscape Scenario Assessment for the Resilient Hills and Coasts Region. Natural Resources Adelaide and Mount Lofty Ranges, Department of Environment, Water and Natural Resources, Adelaide.

• Catastrophic loss of biodiversity (Loss of habitat and significant populations of plants and animals).
• Changes in plant species composition and structure due to loss of fire-sensitive plant species.
• Too severe fires can lead to elimination of plant populations, even those that possess some adaptations to fire.
• Increased weed invasion following fire.
• Loss of hollows in large trees (however fire also can also enhance hollow development in some instances).
• Reduction in invertebrate numbers and diversity.

• Disruption of life cycles of plants and animals, and has the potential to prevent plants and animals from recolonising the area.
• Changes in plant species composition and structure due to loss of fire-sensitive plant species.
• Increase in nutrient levels which aid weed growth.
• Increase in weed invasion.
• Reduction in the capacity for native plants to germinate through increased competition with weeds, thereby increasing the fire risk.
• Prevention and reduction of native seed set in soils.
• Loss of woody debris and leaf litter which provides habitat and enhances soil health and protection from erosion.

• Can threaten plant populations by damaging those flowering/seeding or sensitive juvenile plants.
• Can threaten fauna population during optimal breeding times.

• Changes in plant species composition and structure due to loss of those plant species that may rely on a fire event to regenerate.
• Reduction in optimal habitat for some species.

• Loss of hollows and habitat trees.
• Injury and death of wildlife falling from trees (birds, bats, possums, koalas etc).
• Damage and loss of habitat (nests and hives etc).

• Drowning of wildlife caught in flood waters or inundated in dens and burrows.
• Wind/water erosion to creeks and river banks, exposed sites, hill-slopes, and floodplains.
• Excessive deposition of sediment, smothering vegetation and potential habitat.
• Loss of plant species on creek banks.
• Influx of nutrients in creeks, rivers and reservoirs.
• Dispersal of weed species.
• Dispersal of exotic fish species.
• Loss or reduction of wetland function.
• Release of pollutants from flooded sewers etc.
• Erosion of soils and potential loss of already very low levels of nutrients.

• Wildlife death and injury.
• Large-scale loss of habitat.
• Local extinctions of entire populations of plants and animals.
• Displacement of wildlife.
• Increased vulnerability to wildlife from predators, traffic and interaction with humans.
• Increased weed recruitment and promotion of invasive species.
• Exposed soils vulnerable to erosion and potential loss of already very low levels of nutrients.

• Wildlife death.
• Increased vulnerability to stressed wildlife (eg koalas and possums seeking water on the ground).
• Death and loss of plant species.
• Reduction in plant recruitment.
• Interference/interruptions to wildlife breeding cycles.

There are a number of designated horse riding trails within the Adelaide Hills Council region. This ensures that trails are able to be maintained to minimise erosion and control any weeds. Find details on the HorseSA website.

The State Government is working to establish Adelaide and the Mount Lofty Ranges as an international mountain biking destination, building on the already extensive network of trails across national parks, forest reserves and other public land.

Find more information on the Visit Adelaide Hills website.

Some of the direct causes of ongoing contamination of waterways include:

• Faulty or leaking septic tank systems;
• Direct access to waterways by livestock, which exacerbates erosion of banks, stirs up sediment and contaminates water with faecal matter;
• Runoff from overgrazed and cropping areas delivers excessive sediment and nutrients in to the waterways¹;
• Stormwater runoff can carry pesticides, fertilizers, rubbish, oil, heavy metals from human activities (eg. Cultivation, livestock management (dairies, piggeries), industry (wineries, abattoirs), landfills, waste and recycling depots and rubbish dumping, wastewater treatment plants).
• Deciduous trees leaf drop in autumn containing high nitrogen content;
• Rubbish dumping.

Once certain contaminants reach waterways, the pollutants can impact directly on the health of native fish, animals, insects and plants that rely on those riparian ecosystems. Other contaminants such as nutrients can cause the excessive influx of unwanted plants and algae that impact natural waterways.

¹ EPA (2000) The State of Health of the Mount Lofty Ranges Catchments from a water quality perspective. Environmental Protection Agency, Adelaide, SA.

In recognition of improving services to the community around litter regulation and local environmental nuisance, the South Australian Parliament passed legislation to support councils to deal with and penalise illegal dumping and littering with the Local Nuisance and Litter Control Bill 2015 coming into effect on 1 February 2017.

Previously, local councils and the EPA managed these issues, as it was not clearly outlined who was the best placed to investigate them. The EPA SA will retain responsibility for assisting councils to manage local nuisance complaints and for leading significant illegal dumping investigations, however councils continue to manage smaller-scale unauthorised dumping cases.

The Act introduces higher penalties for the illegal dumping of asbestos, including a maximum $250,000 fine or two year’s imprisonment, whilst other changes include improving surveillance technology to gather evidence and allowing for public reporting of littering and illegal dumping by associating alleged offence to a vehicle’s registered owner. This effectively gives councils better tools for policing and enforcement.

From 1 May 2017, fines are also imposed to those caught littering from their vehicles following a three-month grace period where warning letters were issued in lieu of fines. Fines range from $210 for general litter, $500 for Class B hazardous litter which includes lit cigarettes or butts, used syringes and glass, and $1,000 for quantities of litter over 50 litres such as illegal dumping.