A Possible Student Biology Research Project: Investigating Historical Mammal Species Loss as an Indicator of Biodiversity Decline
2025 年 17 巻 p. 72-79
詳細
2025 年 17 巻 p. 72-79
Many parts of secondary and tertiary biology curricula in Australia have opportunities for students to undertake research. Biodiversity loss is a major concern to the environmental health of planet Earth and forms parts of the secondary school science subjects, and also biology courses at universities. Here I describe a potential student research project that in-vestigates the loss of biodiversity. It is illustrated by a case study in loss of mammal species in a region of Victoria, Australia. The investi-gation involved searching books and reports written in the 19th Century after European settlement of Victoria that include reference to mammals that once lived in the south-west of the State. Sources were searched detailing past and present distributions of mammals. As well, newspapers (es-pecially regional ones) were searched for mentions of mammals in the same time period. Finally, articles on sub-fossil (Holocene) deposits that contain mammalian remains in the region were ac-cessed. The technique could be applied to any flora or fauna group and the causes of extirpation could be investigated. The case study is an example of a biology research project for senior secondary or tertiary students to carry out in their own locality.
(Received: 15 July 2025; Accepted for publication : 5 August 2025)
biodiversity decline, historical records, mammal extirpation, student research
Author for correspondence: r.wallis@federation.edu.au
Inquiry and research form an important component in Australia’s school curricula. For example, one of the aims of the Victorian Science Levels F-10 Version 2.0 is “an under-standing of scientific inquiry and the ability to use a range of scientific inquiry practices” (Victorian Curriculum and Assessment Authority, VCAA, 2025a – see websites list). Simi-larly, an aim of the Biology curriculum at senior secondary schools is to develop a range of inquiry skills (VCAA, 2022a – see websites list). Research projects are common in universi-ty biology degrees and are often used as preparation for students wishing to enter an hon-ours year in which most of the assessment is through a research project.
In this paper I use loss of biodiversity as a case study topic for a possible secondary sci-ence and tertiary biology research project. The loss of biodiversity is examined specifically in Science Levels 9 and 10 of the Victorian Curriculum F – 10 (VCAA, 2025b – see web-sites list) and in two subjects of the senior secondary (VCE) curriculum Environmental Sci-ence (VCAA, 2022b – see websites list) and Outdoor and Environmental Studies (VCAA, 2024 – see websites list). This case study could be used in these secondary school subjects and in biology at university.
Maintaining biodiversity is an international, national, state and local government prior-ity. UN’s Sustainable Development Goal 15 (Life on Land) has a specific target (number 5) that the extinction of threatened species and overall biodiversity loss will be halted. In Aus-tralia, the National Biodiversity Strategy and Action Plan (Commonwealth of Australia, 2024) has two pertinent aims: to conserve and restore biodiversity and to mainstream biodi-versity considerations into decision-making. Australia was also one of 188 countries to adopt the Kumming-Montreal Global Biodiversity Framework. The Victorian State gov-ernment is committed to stopping the decline of native plants and animals and improving the state's natural environment through its "Protecting Victoria's Environment – Biodiversi-ty 2037" plan (Department of Energy, Environment and Climate Action, 2025). At my local government level, the City of Warrnambool also has a policy Green Warrnambool that states “we will increase the number of indigenous plant and animal species in the munici-pality and ensure that none become extinct” (City of Warrnambool City Council, undated).
Largely because of Australia’s geographic isolation, 87% of Australian mammal spe-cies are endemic – they are found naturally nowhere else in the world. During the last ice age, between 40,000 and 50,000 years ago, a wave of extinction of the Australian megafauna occurred in which 90% of large mammals, birds and reptiles were lost. Possible reasons for this extinction have included a changed climate (Hocknull et al.2020), overhunting by In-digenous communities (Turney et al., 2008; van der Kaars et al., 2017) and habitat change caused by Indigenous humans’ use of fire (Bird et al., 2013).
After European settlement of Australia in the late 18th Century, there occurred another wave of extinction of mammals, many being in what is known as the critical weight range of 55g to 5.5.kg (Ritchie, 2022). Some 38 species (and seven sub-species) of mammals have become extinct in this wave of species loss and another 52 species are listed as critically endangered. Habitat loss, introduced carnivores such as the Red Fox (Vulpes vulpes) and Cat (Felis catus) and for at least two species of marsupial, hunting by European settlers are be-lieved to be the principal causes. Other causes have been introduced herbivores such as Eu-ropean Rabbits (Oryctolagus cuniculus), cattle grazing and disease. Very recently there has been a “third” wave of extinctions, especially in northern Australia (Fitzsimons et al., 2010) where invasion by introduced Cane Toads (Rhinella marina) is an additional threatening process to small and medium-sized mammals.
Here I describe a case study that involves the use of historical records of mammals in the south-west of Victoria, Australia, to chart local extinctions over time and thus provide an indication of biodiversity loss in the region. I believe the techniques could be applied elsewhere to help biology/ environmental studies/ science students investigate the loss of species and in appreciating the changes in environment since historical records were kept. The methods can be adapted for studying any flora or fauna group in a student’s locality.
Four main sources of historical information were used to ascertain the mammalian fauna that previously existed in south-west Victoria, Australia, especially around Warrnam-bool the region’s largest city.
1. Books written by residents or visitors to the region in the 19th Century.
The first permanent settlement in Victoria was in south-west Victoria in Portland Bay in 1834. Six years later, the town of Portland was surveyed. In 1840 the town of Warrnam-bool was surveyed and lots were sold; Warrnambool was formally established as a town in 1855. Thus, I sought books, letters and reports from early European settlers and visitors to the region in the latter half of the 19th Century. One famous book that was referred to by many subsequent authors was written by the first manager of the Bank of Australasia branch in Warrnambool, Samuel Hannaford (1860). Fortunately, this book was republished in1981. Another book that was recommended to me by local historians was that by Dawson (1881). Searching library holdings using terms like “Warrnambool”, “history”, “19th Century” and “fauna” yielded others that proved valuable, especially those by a visitor to the region Bon-wick (1858) and a local newspaper editor Osburne (1980).
Unfortunately, Indigenous communities kept no written records of fauna although ver-bal stories have been handed down through many generations and some early European set-tlers carefully documented what they were told by Aboriginals (e.g. Dawson, 1881).
2. Newspaper reports that mention mammals in the area.
Many national and state newspapers have been digitised by the National Library of Australia (see website list) in a database called Trove, but unfortunately, only a few region-al newspapers can be searched electronically. Using Trove, I entered key words such as “mammals” and “south-west Victoria” and specified a time period before 1st of January 1900. Often, I had to enter key words that described particular species that I suspected had once been present in the region, such as “wombat” or “native cat”. Sometimes a Melbourne-based newspaper referenced an article in one of Warrnambool’s newspapers. I then used the microfilm holdings in the Warrnambool City Library to locate the article that had been mentioned in the local newspaper to gather more detail.
The Portland Guardian and Normanby General Advertiser was first produced on Au-gust 20, 1842, and is generally regarded as Victoria’s first newspaper. Warrnambool’s newspapers began in 1849. There were 16 different titles coming out of Warrnambool in the 19th Century.
Wallis (2023) contains reports in books and newspapers relevant to mammals living in the south-west Victoria in the 19th Century.
3. Sources that have mammal past and present distribution lists
There are several books (e.g. Menkhorst, 1995; Baker and Gynther, 2013) and web sites (Atlas of Living Australia, undated; Victorian Biodiversity Atlas, 2025 – see websites list) that have past and present Australian mammal distribution maps.
4. Subfossils
Subfossils are the remains of organisms that existed from about 12,000 years ago to present day. In south-west Victoria we have been fortunate for reports of mammal fossils present in a series of caves and middens researched by Wakefield (1964). Some of the caves have been called “death traps” as animals fell into chasms on the ground surface. Others were once feeding sites for owls or marsupial carnivores. Other subfossil sites are in kitchen middens of Indigenous communities – these are cooking and feeding sites where the food remains often accumulated into large deposits. Some middens are quite recent and suggest a fauna that lived at the time of European settlement of south-west Victoria.
Using the four sources (methods) above, the following mammals that once lived in the local area (south-west Victoria) that are no longer found there were determined.
Common or Bare-nosed Wombat (Vombatus ursinus)
Samuel Hannaford lived in Warrnambool for two years after moving there in 1854 to take up a bank manager’s role. He visited Warrnambool several times later and in 1860 pub-lished his book on natural history of the western Victorian coast (Hannaford, 1860). One mammal he found living on the Warrnambool coast was the Bare-nosed Wombat, a large burrowing marsupial. Climbing a steep hill in the town, Hannaford noted the large number of burrows of what he described as the uncouth wombat. He also met a citizen who had hand-reared pouch-young of killed wombats. Two years earlier, Bonwick (1858) also wrote on wombats but rather disparagingly: “The sand which lies on the limestone and under the soil…is a famous resort for the Wombats. These pig headed, pig bodied and pig sized mar-supials are fat, chubby sort of creatures, keeping very bad hours, for they sport at night, but afford a delicious supper for the Blacks, and not despicable to the palate of Whites” (Bon-wick, 1858, p. 65). Dawson (1881) also noted that wombats were a favoured food of Indige-nous communities.
There were also several newspaper articles that mentioned wombats living in the 19th Century in and around Warrnambool (Wallis and O’Callaghan, 2018). Wombat sub-fossils have also been found in seven sites in western Victoria, including some quite recent Aborig-inal middens (Wakefield, 1964).
The last known living wombat in Warrnambool was found in 1954 (Wallis and O’Callaghan, 2018). Causes for the extirpation of wombats could have been urbanisation and eradication by farmers because they were considered a pest.
Quolls (Dasyurus spp.)
Two species of dasyurid carnivorous marsupials once lived in the 19th Century Warrnambool district (Wallis, 2021). Evidence for the presence of these attractive species comes from all four categories of sources – books and reports, newspaper articles, past and present distribution maps and sub-fossils.
The Eastern Quoll (D. viverrinus) – historically called the native cat – no longer lives in the wild on the Australian mainland. The Spot-tail Quoll (D. maculatus) survives but in very low numbers. Both species regularly raided chicken coops and were shot, poisoned and hunted by landholders. Only when quoll numbers had plunged did authorities realise their value in preying on European Rabbits that were causing so much environmental damage. It is also believed that a toxoplasmosis-like disease affected quolls (and many other dasyurid marsupials) in the late 1800s and early 1900s.
Quolls have been found in midden deposits as sub-fossils in Warrnambool (Wakefield, 1964).
Bandicoots (Perameles spp., Isoodon obesulus)
Bandicoots are cat-sized marsupial omnivores with pointed snouts. Three species have been found in sub-fossils in south-west Victoria but only one persists and in very low num-bers today. None exist near Warrnambool. The three species were all reported in books by Hannaford (op. cit.) and Dawson (op. cit.) and in a few newspapers.
Toolache Wallaby (Notamacropus greyi)
The marsupials described above all still live elsewhere in Australia; they have thus become locally extinct or extirpated in south-west Victoria. However, the Toolache Wallaby that once dwelt in grasslands and wetlands in the region, is now totally extinct. This grace-ful and most attractive wallaby proved a good quarry for English settlers who were starved of species to hunt on horseback; while habitat change and the draining of wetlands certainly caused a decline in Toolache numbers, hunting had a major effect as well (Menkhorst, 1995).
Wakefield (1964) found bones of Toolache Wallaby specimens in middens very close to Warrnambool as well in another cave fossil site 100km from Warrnambool. There have been no historical reports of this species in books or newspapers, but the distribution data indicate the wallaby once lived in the far south-west Victoria (Menkhorst, 1995).
White-footed Rabbit-rat (Conilurus albipes)
The White-footed Rabbit-rat (Conilurus albipes) was an attractive, large, native ro-dent that was once widespread throughout Eastern Australia and is now sadly extinct. The species is one of four so called tree-rats of which three species remain in northern Australia. The term ‘tree-rat’ is derived from their habit of resting during the day in tree hollows and in fallen limbs.
This rat became extinct only 30 years after it was described by English settlers. It may have been preyed on by cats (it became extinct before foxes and rabbits became widespread in Australia) but the most compelling hypothesis could be the species’ association with yam daisies (Microseris spp.). Yam daisies have underground tubers that Conilurus ate and which Indigenous communities farmed. As Indigenous peoples were driven off their lands, so too did the yams decline and the rats that depended on them became extinct (Wallis, 2024).
There have been no sub-fossils or mentions of Conilurus in newspapers or by visitors to Warrnambool in the 19th Century. However, sub-fossils have been found some 100km west and north-east of Warrnambool and yam daisies occurred near Warrnambool. I have speculated that suitable habitat for Conilurus (and the yams) was abundant in the south-west and thus surmised this beautiful rodent may well have once lived there (Wallis, 2022).
Dingo (Canis lupus dingo)
Dingoes are thought to have entered Australia about 4,000 years, introduced by Indo-nesian seafarers but they are still considered native mammals (Menkhorst and Knight, 2001). The Dingo is a subspecies of dog. There are many reports of Dingoes in newspapers from Trove searches. Almost all the pre-1900 articles were about their status as pests and how they preyed on sheep. Pure Dingoes are no longer found in south-west Victoria. There have been no Dingo remains found as sub-fossils in the region.
Other sub-fossil species
Many mammals listed by Wakefield as sub-fossils no longer live in Victoria. These include the Tasmanian Devil (Sarcophilus harrisii), Thylacine (Thylacinus cynocephalus) – now extinct, and two small macropodids, a pademelon and a bettong. However, some of these species were lost well before Europeans settled in the area. Thus, presence as sub-fossils is the only indication of the species’ prior existence in south-west Victoria. Investi-gating the possible reasons for the loss of these species would be a worthwhile research question for students.
In this paper I have described how evidence of mammal species that once lived in an area can be sought. I believe this methodology could be used in the biology classroom by students investigating the decline in biodiversity in their local area. Many newspapers have now been digitised and can be searched for species records and reports with search criteria including time periods and location. Local libraries often have books on historical natural history. Students could also search international conservation sites, such as the IUCN Red List of Threatened Species (IUCN, 2025 - see website list) for data on relevant species but I found sufficient detail in the listed sources. Finally, sub-fossil records could be searched for relevant species in the appropriate localities. Students undertaking research into lost fauna or flora from their area could search research web sites such as Google Scholar and key in “subfossils” and their region to see if there are relevant published works available. As well, state and national museums may well have displays and records of local subfossils.
I am indebted to Dr Nobuyasu Katayama of the Tokyo Institute of Biology Education for his extremely valuable and constructive suggestions about earlier versions of this paper.
