Surveying Platypus and Rakali populations in the Oberon region
Current status of this initiative
Discussion and planning stages only. Time lapse cameras are currently being tested before designing a systematic survey of key water courses in the Oberon LGA (at least the Duckmaloi and Fish Rivers and their tributaries, possibly other rivers). More information and project plans will appear here in due course.
A rakali (Australian native water rat, scientific name Hydromys chrysogaster) caught on a trail camera camera deployed in Stone Creek, O’Connell by Kyla Ries
Introduction
Anecdotally, rivers in the Oberon region used to be famous for their abundant platypus populations – in fact, there is a story, probably apocryphal, that the name of the Duckmaloi River, which runs through Oberon LGA, came from the surprised exclamation of Irish settlers on first encountering a platypus: “Duck-mole-oy!” (“oy” being what you said if you wanted someone to agree with you). Certainly a lot of research last century into the extent and behavious of the platypus was conducted in river systems around Oberon by researchers associated with Taronga Zoo and various NSW universities – copies of some scientific papers and reports on platypus in the Duckmaloi River, several by local resident Amanda MacLeod, can be accessed here, here and here.
Much less is known about the extent in the Oberon region of the rakali, also also known as the rabe, the “Australian Otter” or native water-rat, (scientific name Hydromys chrysogaster). This elusive creature lives in burrows on the banks of rivers, lakes and estuaries and feeds on aquatic insects, fish, crustaceans, mussels, snails, frogs, bird’s eggs and small water birds – and thus, it often shares similar habitats to the platypus, hence its inclusion here.
ABC News article on the elusive rakali
A recent article published by ABC News on the rakali, and a call for citizen scientists to log sightings of it, is available here. This is something which OCSN members intend to get involved in!
There are several time-lapse camera videos showing the results of platypus and rakali surveillance in the upper Duckmaloi River on our Gallery page.
NSW BioNet Atlas records of platypus and rakali sightings or trappings in Oberon LGA
BioNet is a database of flora and fauna information collected over many decades from multiple sources, operated by the NSW Department of Planning and Environment (DPE). The role of BioNet is described by the DPE thus:
BioNet aims to improve biodiversity outcomes by enabling the community and government to proactively manage and enhance biodiversity in New South Wales through comprehensive, credible and robust data and information.
It is also important because threatened and endangered species records in BioNet must be used by assessors of proposed developments in order to avoid or minimise impacts on wildlife, and is also used as part of the Biodiversity Assessment Method (BAM), which is used as part of the legislated Biodiversity Offsets Scheme (currently under review due to numerous flaws found by the Audit Office of NSW).
Note
The data shown below were manually downloaded from the NSW government BioNet database on 24 September 2024. It is intended to convert these charts and maps to automatically update once a week with the latest data from BioNet once an API access key has been obtained.
The chart below shows the trend in platypus and rakali records in BioNet. These trends may reflect frequency of observations and survey efforts as much as declines or fluctuations in the animal populations or extents. This is an issue which OCSN hopes to address over the next few years by mounting regular, systematic surveys of platypus and rakali activity in key water courses in Oberon LGA, using a combination of direct observation and time-lapse camera recordings (see below). Note that there are very few observations of rakali. This may be because they are rare, but also because they are elusive – but see the video of a rakali captured by OCSN committee member Kyla Ries on this page.
As can be seen, the small number of records, particularly recent records, for platypus and rakali in BioNet is a bit disappointing, and distressing. However there is a more inclusive source of biodiversity data we can query.
Australian Living Atlas (ALA) records of platypus and rakali observations or trappings in Oberon LGA
The Australian Living Atlas (ALA) is a fantastic resource, partially funded by the Australian Research Data Commons (ARDC). ALA collates biodiversity data from many sources into a single database, which in turn is made available as part of the Global Biodiversity Information Facility (GBIF).
In the table below, we can see the various sources and numbers of records for platypus and rakali sightings in Oberon LGA over time. Data which was downloaded from NSW BioNet Atlas is also shown in the table for comparison – it should match the ALA data for the same source, but it doesn’t. This needs to be investigated in due course – there seems to be a delay in BioNet data being added to the ALA database – but for now, we will just present the ALA data here.
Note
Duplicate records in the ALA database have been filtered out of the data presented in the tables and maps below – only the record marked as REPRESENTATIVE, where records appear to be duplicated, is included. Similarly only those records flagged as spatiallyValid==TRUE are included. See also the warning below regarding spatial precision, which is different from spatial validity.
| Platypus and Rakali records for Oberon LGA | ||||||
|---|---|---|---|---|---|---|
| in the Australian Living Atlas (ALA) database with comparable data direct from NSW BioNet Atlas also shown | ||||||
| Decade | ||||||
| 1970-1979 | 1980-1989 | 1990-1999 | 2000-2009 | 2010-2019 | 2020-2029 | |
| Platypus | ||||||
| ALA species sightings and OzAtlas | - | - | - | - | 11 | - |
| Australian Platypus Conservancy | - | - | - | 2 | 7 | 5 |
| cPlatypus1 | - | - | - | - | 1 | 13 |
| Encyclopedia of Life Images - Flickr Group2 | - | - | - | - | 2 | - |
| iNaturalist Australia3 | - | - | - | 4 | 17 | 1 |
| NSW BioNet Atlas (direct) | - | 2 | 17 | 61 | 16 | 16 |
| NSW BioNet Atlas (via ALA) | - | 21 | 11 | 41 | 22 | 7 |
| All sources | 0 | 23 | 28 | 108 | 76 | 42 |
| Rakali | ||||||
| ALA species sightings and OzAtlas4 | - | - | - | - | 1 | - |
| Australian Platypus Conservancy5 | - | - | - | 2 | 6 | 8 |
| NSW BioNet Atlas (direct) | 1 | - | 2 | 1 | 2 | - |
| NSW BioNet Atlas (via ALA)6 | 1 | 1 | 1 | 1 | 2 | - |
| All sources | 2 | 1 | 3 | 4 | 11 | 8 |
| 1 cPlatypus - see also platy-project | ||||||
| 2 Encyclopedia of Life Images - Flickr Group | ||||||
| 3 iNaturalist Australia | ||||||
| 4 ALA species sightings and OzAtlas | ||||||
| 5 Australian Platypus Conservancy | ||||||
| 6 NSW BioNet Atlas (via ALA) | ||||||
Interactive maps
In the maps below, you can toggle layers on and off for platypus observation records in each decade, as well as for rakali records for the entire period since 1970. Zoom in to see individual sighting records where they overlap. If you click on each platypus or rakali icon on the map, additional details about the record in the ALA database will pop up. Merging of NSW BioNet records that are not (yet) in the ALA database is planned, as soon as BioNet approves OCSN access to the API they provide for automated data extraction (we are using such automated data extraction for the ALA data shown here).
Variable geographic precision!
Please note that the geographic position of the icons in the map below may not be precise. Some records provide precise position information, in which case the locations are accurately shown, but many provide imprecise information so as to protect the exact locations from unwanted attention or interference. If you click on an icon, the pop-up information will show the positional accuracy information (in metres) where it is available for that record. Often it is very approximate eg within 10 km! Unfortunately not all data sources which contribute to the ALA database seem to report positional accuracy. Anyway, please be aware of this important limitation of the data, which in many cases is an intentional limitation to protect vulnerable and endangered species or populations.
All Platypus and rakali observations in Oberon LGA recorded in the Australian Living Atlas (ALA) database
platy-project platypus observations in Oberon LGA found in the Australian Living Atlas (ALA) database