A straw shows which way the wind blows: Threatened biodiversity in Australian Capital Territory

Jiacheng He (U5931175)

The Australian Capital Territory (ACT), where contains the Australian capital city of Canberra and other surrounding townships, is developed throughout the 20th century. During the development of the ACT region, original landscapes were largely modified (Finlayson, 2012). Artificial disturbances strongly influenced regional biodiversity, various species and ecological communities were listed as endangered/critically endangered in recent decades, such as the Swift Parrot (Lathamus discolor) and the Yellow Box/Red Gum Grassy Woodland. My volunteer experience includes a bird survey with Assoc. Prof. Philip Gibbons, and a natural reserve maintenance with the Friends of Mount Majura (FoMM). Two working experiences provided me some similar perspectives about the status of biodiversity (and the conservation) in the ACT area.

The Bird Survey

Picture 1. Isolated mature tree. Photoed by Jiacheng He

This survey began in a sunny morning, we divided into pair-work groups then evaluated the ecological value of mature trees on different study sites (on nature reserves, public greenspaces and leasehold properties). The adopted method was observing and recording the frequency/abundance of bird presence/behaviour on certain mature trees. Expected and actually observed bird species include Crimson Rosella (Platycercus elegans), sulphur-crested cockatoo (Cacatua galerita), pied currawong (Strepera graculina) and noisy miner (Manorina melanocephala).

Picture 2. Sulphur-crested cockatoo in the hollow. Photoed by Jiacheng He

As a continuous research plan, bird surveys are designed to demonstrate that compensatory small trees cannot adequately be the offset of large old trees. According to the prior publications (Le Roux et al., 2014; Le Roux et al., 2015), mature trees are able to provide more favourable habitats for various bird species with breeding hollows. Also, there is no doubt that planting new and smaller trees are important in the urban landscapes. For the reason that increasing paddock trees indicate better habitat connectivity in the future.

During the survey, Phil introduced a lot about the conservation status of these isolated mature trees. In the ACT area, population increase stimulated the urban expansion. And developmental plans prefer to fully clear most of the mature trees rather than keep necessary numbers of them. And it’s a pity to hear that several study sites will be cleared for residential constructions.

Picture 3. The area to be cleared for constuctions. Photoed by Jiacheng He

Jobs at The Fair Project Site

Picture 4. Entrance of The Fair Project Site. Photoed by Jiacheng He

I gained a work opportunity at the Fair Project Site, where is a small part of the Mt. Majura nature reserve. Waltraud, the project manager of the FoMM, introduced me about the site and some background knowledges. Other volunteers and I started from the weed control, and we focused on the Paterson’s Curse (Echinum plantagineum).

Picture 5. Paterson’s Curse. Avaliable from the Agriculture Victoria

This herb species is the most numerous weed species on the Fair site, and it is an invasive species that can rapidly seed after the blossom. We excluded every Paterson’s Curse we found, and the plants with flowers were gathered and taken out of the site.

Picture 6. Mulching. Photoed by Jiacheng He

Then we mulched for regenerated plant species, mulching can suppress growth of weeds, maintain humidity, prevent soil erosion and add nutrients to the soil. During the job, we talked about the environmental degradations on the site. The major degradations are considered to be: soil compaction due to the urbanization; weed invasion due to inappropriate past land management; loss of topsoil and understorey diversity due to overgrazing. It was emphasized that all the conserving offsets of this site own no governmental funds. And the FoMM can only conserve and re-plant endangered species but cannot deal with the kangaroo overgrazing.

Picture 7. Protected and regenerated species. Photoed by Jiacheng He

Work experiences with Phil and Waltraud let me realize that the biodiversity in ACT is still facing various threats, although many conservation plans have been applied. The government/decision makers should concern more about the degrading biodiversity and try to find feasible solutions (i.e. limit the urbanization; support significant conservation; control the kangaroo overpopulation).

Picture 8. Offsets on The Fair Project Site

References

Finlayson, D. (2012). Canberra landscapes shaped by geology: the centenary of Pittman’s 1910 geological map that helped shape the design for Australia’s capital city. Canberra Historical Journal 69: 1-4.

Le Roux, D.S., Ikin, K., Lindenmayer, D.B., Manning, A.D., Gibbons, P. (2014). The Future of Large Old Trees in Urban Landscapes. PLOS One 9(6): e99403.

Le Roux, D.S., Ikin, K., Lindenmayer, D.B., Manning, A.D., Gibbons, P. (2015). Single large or several small? Applying biogeographic principles to tree-level conservation and biodiversity offsets. Biological Conservation 191: 558-566.

About Biodiversity Conservation Blog

I am an Associate Professor at The Australian National University and convene a (very awesome) course called Biodiversity Conservation. Myself and students in the course contribute to this blog.
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