Great Southern Bioblitz

The inaugural Great Southern Bioblitz (GSB) was in 2020.  The Castlemaine Field Naturalists Club joined in 2021 and has taken part every year since. Each Bioblitz is held over 4 days in spring (September to November) with an iNaturalist project established to collect the observations.  Observations, photos and/or recordings within the Mt. Alexander Shire and the eastern half of Hepburn Shire are uploaded to iNaturalist where they are included in our project. 

From 24th – 27th October 2025 we will be taking part in the Bioblitz for the fifth time. Watch for our posts giving details of special events. In the meantime you can prepare for the GSB by familiarising yourself with iNaturalist and working out where to go exploring.

The Journey So Far

This article is the first interrogation of the accumulated data.  The analysis is not exhaustive but will perhaps offer suggestions for more detailed analysis and how to prepare for future Bioblitz. There are many factors which can influence the bias of the data including seasonal factors, mismatched timing of the bioblitz across years, and the many human factors such as rare or conspicuous species being over-represented.

In the tables below, the numbers are a snapshot at a point of time in the weeks following the bioblitz. While the number of observations will remain constant, the number of observations at Research Grade will increase over time as observations are identified. The number of Threatened Species may also change as the threat status for various species is updated.

Spring 2021: 22nd to 25th October
This was the first year that we took part in the GSB. See the summary (below) of what we found in 2021 and take a closer look at our project and the Umbrella site for the year which shows all groups.

See notes below for an explanation of the categories.	Total	Plants	Birds	Insects	Amphibians	Arachnids	Fungi	Mammals	Molluscs	Reptiles
All observations Verifiable	1828	1221	168	292	4	47	54	7	1	14
All observations Research Grade	1266	938	166	103	4	15	6	6	1	14
All species Verifiable	575	322	63	119	2	21	24	4	1	11
All species Research Grade	430	277	63	53	2	11	5	3	1	11
All Observations Threatened	16	15	1

Spring 2022: 28th to 31st October.
See the summary (below) of what we found in 2022 and take a closer look at our project and the Umbrella site for the year which shows all groups.

See notes below for an explanation of the categories.	Total	Plants	Birds	Insects	Amphibians	Arachnids	Fungi	Mammals	Molluscs	Reptiles
All observations Verifiable	2173	1384	195	274	16	26	207	30	5	8
All observations Research Grade	1439	1020	194	108	13	7	41	27	4	7
All species Verifiable	622	347	63	112	4
All species Research Grade	452	273	63	66	4	6	16	8	2	7
All Observations Threatened	14	11	3

Spring 2023: 24th to 27th November
See the summary (below) of what we found in 2023 and take a closer look at our project and the Umbrella site for the year which shows all groups.Spring 2023: 24th to 27th November

See notes below for an explanation of the categories.	Total	Plants	Birds	Insects	Amphibians	Arachnids	Fungi	Mammals	Molluscs	Reptiles
All observations Verifiable	2474	1128	375	738	18	65	65	33	4	18
All Observations Research Grade	1579	862	372	330	15	29	4	33	4	17
All species Verifiable	721	292	85	254	5	29	15	14	1	5
All species Research Grade	456	233	85	134	5	11	4	14	1	5
All Observations Threatened	16	12	3					1

Spring 2024: 20th to 23rd September
See the summary (below) of what we found in 2024 and take a closer look at our project and the Umbrella site for the year which shows all groups. In 2024 we had 62 observers taking part and 192 people contributed identifications.

See notes below for an explanation of the categories.	Total	Plants	Birds	Insects	Amphibians	Arachnids	Fungi	Mammals	Molluscs	Reptiles
All observations Verifiable	1208	804	98	205	13	33	28	10	4	3
All Observations Research Grade	878	663	97	72	11	12	4	10	2	2
All species Verifiable	388	186	58	87	5	21	17	3	3	3
All species Research Grade	275	153	57	36	5	10	4	3	2	2
All Observations Threatened	15	12	2

Notes

‘Verifiable Observation’

This status is applied to any observation that is uploaded that contains a valid date, a location, has photo or sound, and isn’t of a captive/cultivated organism. Without any one of these vital pieces of information, an observation cannot reach Research Grade and is not shared with the Atlas of Living Australia (ALA). Reseach Grade observations are a sub-set of Verifiable observations.

‘Research Grade’

This status is achieved when a ‘Verifiable Observation’ has been reviewed and the community is in agreement on the ID. The observation will now be shared with the ALA and other iNaturalist partners.

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In the graphs below, the category ‘All other categories’ is the sum of ‘Amphibians, Arachnids, Fungi, Mammals, Molluscs, Other Animals & Reptiles’. In these groups there were insufficient observations for meaningful comparisons.

The first point to note is that the number of observations increased each year (Charts 1 & 2) but decreased in 2024.  In the earlier years the number of participants increased from 28 in 2021 to 38 in 2022 but 37 in 2023 which largely explains the increase in observations.  In 2024 there was a big increase to 64 participants however the 2024 GSB was earlier in the year (September compared to late October/November) and suffered from inclement weather for most of the four days which accounted for the lower number of observations. The increased number of observers in 2024 is at least partly attributable to the very well attended guided walk that we held in Muckleford Forest. Although there is a core group of observers who have participated in all 4 Bioblitz, there are others who have participated in only one of the four Bioblitz.  The increase in total observations from 2022 to 2023, 38 and 37 observers respectively, could be due to the increased experience of each of the observers in 2023.

Bioblitz 2022 shows a significant increase in plant observations.  The timing was shortly after the heavy rainfall.  The data were not examined to identify how many invasive weeds were included.  However, in late November 2023, many native plants had already finished flowering and they may have been overlooked. 

In 2023, the moth night, held on November 25^th was the first time for this dedicated activity.  Together with the later time of the year and the milder weather, these factors may account for the higher number of insect and bird observations in 2023.

In 2024 we held two special events where Bioblitzers could meet others taking part in the Bioblitz while getting up close to our native flora and fauna with the help of expert guides. The first was a Moth Night in the Castlemaine Botanic Gardens with Steve Williams, where dozens of moth species were attracted to the lit moth sheets. Then on the Sunday a Guided Walk at Red, White and Blue with Geoff Park, Frances Cincotta, Andrew Skeotch and Patrick Kavanagh was organised by our friends at Newstead Landcare, a very popular and productive event

Also noteworthy is the increase of Fungi observations in 2022.  Again this may be attributable to the high rainfall in late winter and spring.

While the total number of observations is fixed for the time of each GSB project, species identification values may change as experts and knowledgeable people make further confirmations upgrading observations from ‘Needs ID/Verifiable’ to ‘Research Grade’ status (Charts 3 and 4).  The quality of the photos which include clear identification features may also influence the level of species identification as will the number of people with sufficient knowledge to accurately identify some species.

Personal preferences, locations (grasslands, forests creeks or higher altitude), time of day/night, the season and weather (rain, sun, wind) will always influence which observations are made. 

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Threatened Species

The ‘Threatened’ classification is a grey area.  It may be influenced by data sources such as:
(1) The International Union for Conservation of Nature’s Red List of Threatened Species (IUCN Red List); In the table below the IUCN threat status may only be relevant to some named sub-species.
(2) The Federal Government’s Environment Protection and Biodiversity Conservation Act 1999 (EPBC);
(3) The Victorian Government’s Flora and Fauna Guarantee Act 1988 (FFG);
(4) Other regional and local data sources such as – Threatened Species Scientific Committee, Indigenous Advisory Committee and the CSIRO among others.

For example, The IUCN and iNaturalist list the European Rabbit Oryctolagus cuniculus as ‘Threatened’ within its natural range in areas of Europe and north Africa!!  iNaturalist lists the Fryerstown Grevillea, Grevillea obtecta as ‘Threatened’ but the FFG lists it as ‘Endangered’ while it is not listed at all on the IUCN.  FFG lists the Small-flower Grevillea Grevillea micrantha as Critically endangered.

During the GSB Castlemaine 2021 and 2023, the European Rabbit was observed and uploaded into the respective projects.  They are valid observations and have been identified at research grade but the European Rabbit, has not been included in this survey as a ‘threatened’ mammal’ in the Mt. Alexander / Hepburn Shires. Red-flowering Gum, Corymbia ficifolia, and Pincushion Hakea, Hakea laurina, both native to WA and introduced to our region were likewise, not included in the analysis.

Nearly all threats to the global flora and fauna can be attributed to humans – the conflict between human activities and the conservation of our environment.  Some of the major threats include global warming, habitat loss due to exploitation of natural resources or changed land use, the over-exploitation of wildlife and plants for commercial purposes including trade of rare or charismatic species, novel diseases and competition from the introduction of invasive non-native species.  While many species may be threatened locally due to human or environmental factors this local status has not been picked up by this analysis. 

Threatened Species Native to our Region found during the GSBs

Common Name	Scientific Name	Threat Category	2021	2022	2023	2024
Common Yabby	Cherax destructor	Vulnerable (IUCN)				X
Australasian Shoveler	Spatula rhynchotis	Vulnerable (FFG)				X
Hardhead Duck	Aythya australis	Vulnerable (FFG)			X
Musk Duck	Biziura lobata	Vulnerable (FFG)	X	X
Gang-gang Cockatoo	Callocephalon fimbriatum	Endangered (EPBC)		X	X
Powerful Owl	Ninox strenua	Vulnerable (FFG)			X	X
Diamond Firetail	Stagonopleura guttata	Vulnerable (FFG)		X
Koala	Phascolarctos cinereus	Endangered (EPBC)			X
*Coulter Pine	Pinus coulteri	Near Threatend (IUCN)				X
Late-Flowered Flax-lily	Dianella tarda	Critically Endangered (FFG)	X		X
Ornate Pink Fingers	Caladenia ornata	Endangered (FFG)	X	X
Golden Cowslips	Diuris behrii	Endangered (FFG)	X	X
Cassinia diminuta	Cassinia diminuta	Endangered (FFG)			X
River Red Gum	Eucalyptus camaldulensis	Near Threatend (IUCN)	X		X	X
Wiry bossiaea	Bossiaea cordigera	Endangered (FFG)			X
Long-leaved Box	Eucalyptus goniocalyx	Vulnerable (IUCN)	X		X	X
Yellow Gum	Eucalyptus leucoxylon	Vulnerable (IUCN)		X	X
Yellow Box	Eucalyptus melliodora	Vulnerable (IUCN)	X		X
Grey Box	Eucalyptus microcarpa	Endangered (IUCN)	X	X		X
Red Box (Silver Dollar Gum)	Eucalyptus polyanthemos	Some sub-species	X		X
Manna Gum	Eucalyptus viminalis	Near Threatend (IUCN)	X			X
Goldfields Grevillea	Grevillea dryophylla	Endangered (FFG)		X	X	X
Small-flower Grevillea	Grevillea micrantha	Critically Endangered (FFG)		X	X
Fryerstown Grevillea	Grevillea obtecta	Endangered (FFG)	X	X	X
Creeping Grevillea	Grevillea repens	Endangered (FFG)	X
Hairy Geebung	Persoonia rigida	Vulnerable (IUCN)		X		X
Dense Mint Bush	Prostanthera decussata	Endangered (FFG)	X	X		X
Scented Bush-pea	Pultenaea graveolens	Endangered (FFG)	X	X	X	X