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Chaminda Alahakoon

Candidature

PhD Candidate

Thesis title

Temperature and water stress on seed germination and seedling emergence of native plants in the Cumberland Plain

Research project

Chaminda AlahakoonClimate change has been identified as a major threat to biodiversity and ecosystem function. The Cumberland Plain located in Western Sydney; home to over a hundred threatened species and ecological communities, is vulnerable to loss of biodiversity through increasing frequency and intensity of extreme climatic events. The response of native plants in the region to temperature and water stress is largely unknown, despite being crucial drivers of seed germination and seedling emergence. Seed germination proceeds under a particular range of favourable temperatures and water potentials. Germination rates may decline under warming and water limitation as seeds find themselves outside of suitable conditions. The impacts of climate change are not equally distributed among plant species and ecological communities, as some have greater sensitivity and exposure to temperature and water availability. My PhD project aims to study the sensitivity of plant species in threatened ecological communities in the Cumberland Plain to extreme climate events based on their seed germination response. Laboratory experiments will be conducted to determine the optimal and threshold temperatures and water potentials for germination. Impacts of reduced rainfall and warming on seedling emergence and establishment will be studied under climate manipulated field conditions. The findings will be validated incorporating the impact of microhabitat conditions by studying seedling emergence and establishment in the Cumberland Plain grassy woodland. The findings of the study will allow to identity the plant species and ecosystems in the Cumberland Plain which are vulnerable to climate change and predict shifts in ecosystem composition in the future. Critically, the outcomes will inform adaptive management strategies to conserve and restore biodiversity under climate change.

Publications

Alahakoon, A.A.C.B., Perera, G.A.D., Merritt D.J., Turner S.R., & Gama-Arachchige, N.S. (2020). Species-specific smoke effects on seed germination of plants from different habitats from Sri Lanka. Flora, 263.
Alahakoon, A.A.C.B., Abeysiriwardena D.S. de Z., Damunupola J.W., Hay F.R. & Gama-Arachchige N.S. (2021). Accelerated aging test to predict seed vigor in terms of field emergence of wet direct seeded rice. Crop & Pasture Science, 72(10): 773-781.
Alahakoon, A.A.C.B., Abeysiriwardena D.S. de Z. & Gama-Arachchige N.S. (2021). Low seed moisture and polythene packaging improve storability of seed paddy. Journal of Stored Products Research, 94.

Supervisors

Associate Professor Paul D. Rymer, Doctor Rachael Nolan, Associate Professor Mark Ooi, Doctor Cathy Offord