Projects seeking sponsorship

These are projects approved by the Scientific Research Committee and seeking support.

Projects for financial year 2013/14

Epiphyte diversity over varying spatial scales in tropical and sub-tropical Australia

Professor Jamie Kirkpatrick AM
Distinguished Professor of Geography and Environmental Studies, University of Tasmania
School of Geography and Environmental Studies,
Private Bag 78, Hobart, TAS, 7001
Phone: 3 6226 2460 Fax: 03 6226 2989
Email: J.Kirkpatrick@utas.edu.au

Introduction

Epiphytes, plants which grow on other plants for support, are a highly diverse group, representing approximately 9% of the world’s vascular plant diversity (Zotz, 2013). In Australia, there are c. 380 vascular epiphyte species, with the vast majority confined to a very small proportion of the continent: the humid tropical and sub-tropical regions in the north-east (Wallace, 1981). Non-vascular epiphytes, such as the bryophytes (the group consisting of mosses, liverworts and hornworts), are also highly abundant and diverse in Australia’s humid tropical regions (Pócs and Streimann, 2006), as well as in the temperate rainforests of southern Australia (Jarman and Kantvilas, 1995, 2001).

Having no direct contact with the ground, epiphytes rely on regular moisture inputs from fog and rainfall. Therefore, they are highly sensitive to relatively small changes in precipitation and will be greatly affected by climate change (Benzing, 1998, Hietz, 1999, Nadkarni and Solano, 2002, Hsu et al., 2012,). Asplenium nidus, the most common epiphyte in the tropical areas of north-eastern Australia, has high rates of mortality during long dry periods (Freiberg and Turton, 2007). Such periods are likely to increase in frequency and intensity under climate change (IPCC, 2007).

Projected changes in climate are expected to cause major shifts in the locations of environments suited to particular epiphyte species, potentially threatening the less vagile, and those without a suitable future environment, with local or total extinction (Hsu et al., 2012). Many plausible climate models predict a reduction in super-humid areas and associated cloud forests (Still et al., 1999, Foster, 2001, Hilbert et al., 2001), where epiphyte diversity is greatest, leading to a loss in habitat for many epiphyte species (Hsu et al., 2012). For instance, the highland rainforests associated with the super-humid regions of the Wet Tropics region are predicted to lose 50% of their former range with only 1°C degree of warming (Hilbert et al., 2001).

The loss of epiphytes from the forest ecosystem would affect the nutrient balance, water storage capacity and habitat characteristics of the ecosystem (Benzing, 1998). Epiphytes play an important role in the functioning of rainforest ecosystems by capturing and storing fog and atmospheric nutrients which would otherwise be unavailable to the forest, thereby improving the nutrient capacity of the ecosystem (Benzing, 1998, Díaz et al., 2010, Hietz et al., 1999). Epiphytes communities also provide important habitat structure and a food source for many canopy dwelling animal species such as invertebrates, birds and mammals (Hietz, 1999).

Considering the importance of epiphytes to the functioning of rainforest ecosystems, very little research on epiphytes has been conducted within Australia (Cummings et al., 2006). Only one study by Wallace (1981) has examined the vascular epiphyte diversity of tropical and subtropical Australia at the community level. This is extremely surprising considering the high abundance of epiphytes described by some authors in the Wet Tropics region (Wallace and McJannet, 2008), which are home to approximately 165 epiphytic orchids species (Lavarack and Gray, 1985, Jones, 1988). Bryophytes remain understudied in the tropical and subtropical regions of Australia (Pócs and Streimann, 2006), however, they are better documented in the temperate rainforests of Victoria and Tasmania (Jarman and Kantvilas, 1995, 2001, Kantvilas and Jarman, 2004). To my knowledge, no research has been conducted which examines epiphyte distributions over altitudinal gradients within Australia, or assesses the likely impacts of climate change on these distributions.

Costs

Year
2013/14
Maintenance  
Travel 4950.50
GST   450
TOTAL 5400.50

Characterizing the genetic structure of Acacia suaveolens along two climatic gradients in south-east Australia
Alice Hudson (BSc Environmental Science (1st
class Hons); MSc Plant Diversity (Distinction))
PhD Candidate
Institute for Conservation Biology
School of Biological Sciences
University of Wollongong
NSW
2522
Ph (02) 4221 5652
Email: arh785@uowmail.edu.au

The aim of this project is to assess the ability of Acacia suaveolens to respond to climate change through adaptation. I will do this by determining the extent of genetic differentiation between populations along two temperature gradients in south-east Australia and use this data to infer levels of connectivity or gene flow. My sampling will be conducted to test the impact habitat fragmentation will have on gene flow following climate change. This project will form one section of a larger comparative study focusing on three co-occurring species (A. suaveolens, A. ulicifolia and Dillwynia retorta) to assess patterns of variation in life history traits that will allow plants to respond to climate change. The study focuses on the extent to which variation in traits such as germination and seedling growth is determined by phenotypic plasticity or additive genetic variation.

Dry sclerophyll heath / woodland is classified as one of south-east Australia’s last remaining wilderness habitats (Keith, 2004), however the distributional range of this habitat along the coast of New South Wales is projected to face a 1.8 – 3.4 ° C warming by 2070, concurrent with increasing fragmentation (CSIRO, 2007; Keith, 2004). Obligate-seeding Fabaceae (including A. suaveolens, A. ulicifolia and D. retorta) comprise an important aspect of this ecosystems shrub layer (Sprecht, 1970; Auld, 1996; Ooi et al., 2012 and references therein), yet show diversity in their life-histories and general abundance (Auld, 1996). Consequently, they are unlikely to respond in the same ways to the synergistic effects of fragmentation and climate change and must be studied in tandem to gain an accurate understanding of likely habitat changes under climate change. Gene flow between isolated populations is known to be one way in which adaptation to climate change can occur through the transfer of traits involved in local adaptation to different climatic regimes (e.g. Luikart et al., 2003; Harte et al., 2004; Jump et al., 2006). Little investigation into the genetic connectivity of such habitats has been conducted, despite its potential importance. This project seeks to develop a crucial case study for the investigation of the extent of gene flow and genetic structuring on a temperature scale comparable to that of projected climate. The results of this work can be applied to projections of community based effects in the future regarding the potential impacts of climate change on a broader range of species. This project will specifically focus on addressing the following questions:
1. What level of population differentiation exists between populations of A. suaveolens along two temperature gradients in south-eastern Australia?
2. To what extent is gene flow occurring between populations of A. suaveolens?
3. To what extent does natural habitat fragmentation account for the level of genetic differentiation between populations of A. suaveolens?
Outcomes of this project will elucidate the current state of genetic diversity and gene flow for A. suaveolens which can then be compared against two co-occurring species. Collectively, this knowledge can then be used to predict likely responses of these species to climate change in terms of their existing genetic diversity as a source for local adaptation, and the potential for gene flow along the gradient to aid the transfer of traits for local adaptation. Moreover, this study will provide information applicable to modelling future species distributions important for future conservation planning (Hampe, 2004).

budget


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