Elevation and Moths in a Central Eastern Queensland Rainforest
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bs_bs_banner Austral Ecology (2015) ••, ••–•• Elevation and moths in a central eastern Queensland rainforest ERICA H. ODELL,* LOUISE A. ASHTON AND ROGER L. KITCHING Environmental Futures Research Institute and Griffith School of Environment, Griffith University, 170 Kessels Road, Brisbane, Queensland 4111, Australia (Email: erica.odell@griffithuni.edu.au) Abstract Elevational gradients are powerful natural experiments for the investigation of ecological responses to changing climates. Automated modified Pennsylvania light traps were used to sample macro-moth assemblages for three consecutive nights at each of 24 sites ranging from 200 m asl to 1200 m asl within continuous tropical rainforest at Eungella, Queensland, Australia (21°S, 148°E). A total of 13 861 individual moths representing approximately 713 morphospecies and 10 045 individuals belonging to approximately 607 morphospecies where sampled during November 2013 and March 2014 respectively. Moth assemblages exhibited a strong elevational signal during both sampling seasons; we grouped these into lowland and upland assemblages.The dispersal pattern of moth assemblages across the landscape reflected the stratification of vegetation communities across elevation and correlated with shifts in eco-physical variables, most notably temperature and substrate organic matter. Regional historical biogeographical events likely contributed to the observed patterns.The analysis presented here identifies a set of statistically defined elevationally restricted moths which may be of use as part of a multi-taxon predictor set for monitoring future ecosystem level changes associated with elevation and, by implication, with climate. Key words: diversity, elevation, moth, rainforest, stratification. INTRODUCTION have resulted in functional asynchronies among important biological events (Root et al. 2003; Kiers Over the past century, average global temperatures et al. 2010; Thackeray et al. 2010; Rafferty & Ives have increased by 0.78°C (IPCC 2013) and are pre- 2011; Bellard et al. 2012; Nakazawa & Doi 2012). dicted to continue to rise throughout the 21st century Temperature, solar radiation, precipitation, sea level (National Research Council 2008). Pragmatic climate as well as the timing and magnitude of extreme events projections estimate a global shift in average tempera- are all anticipated to change under global climate tures by 3–6°C within the coming century (IPCC change. The likely impacts on biological diversity of 2013), with some areas, such as mountains and high change in several of these variables can be investigated latitudes experiencing greater levels of warming than using elevational gradients. Elevational gradients are others (Diaz et al. 2003; Nogués-Bravo et al. 2007; powerful natural experimental systems for investigat- Kohler & Maselli 2009; World Bank 2012). Under- ing ecological responses to climatic influences (Körner standing the impacts and responses of ecosystems to 2007). They offer a unique opportunity to observe climate change is essential if measures to ameliorate potential responses of ecosystems to climate change by and predict the impacts of climate change are to be presenting naturally steep climatic gradients within effective (Shaver et al. 2000). relatively small geographical ranges and therefore A broad range of organisms from several bio- allow sampling from a narrow species pool. This sub- geographical regions have been shown to have stitution of space for time, however, is not without responded to recent changes in the global climate issues especially given the uncertainty in trajectories of (Parmesan 2007; Cook et al. 2008; Thackeray et al. future change. Nevertheless, by monitoring the 2010). Changes in species distributions and elevational distributions of in situ assemblages, we can phenological events are among the most widely begin to understand how ecosystems may respond to a observed (Williams et al. 2003; Thomas et al. 2004; globally changing climate. In contrast to locations in Chen et al. 2009; Hughes 2012). Shifts in the timing of the Northern Hemisphere, Australia, in general, lacks flowering, bud burst, emergences, migrations and the necessary long-term historical datasets and nesting have been observed (Van Asch et al. 2007; phenological monitoring that have allowed for the Møller et al. 2008; Burkle et al. 2013), some of which detection of a range of biodiversity impacts of climate change to date (Hughes 2003). Recent climate *Corresponding author. warming in Australian is now well established with Accepted for publication April 2015. observable consequences for biodiversity (Steffen et al. © 2015 Ecological Society of Australia doi:10.1111/aec.12272 2 E. H. ODELL ET AL. 2009; IPCC 2014).The establishment of baseline dis- The region’s mountains are frequently covered by a cloud tribution data and the identification of potential pre- cap. This produces condensation which helps maintain a dictor species remains an essential need if our consistently moister environment in the upland forest, par- understanding of climate change, monitoring and ticularly in the dry season. Cloud forests are generally thought management responses are to be sensible and timely of as crucial for the maintenance of high elevation rainforest structure and the associated arthropod assemblages of upper (Hughes 2000; Huddleston 2012). The present paper elevational zones (Nadkarni et al. 2000; Oosterhoorn & contributes one such baseline. Kappelle 2000; Williams-Linera 2002). Direct precipitation Indicator species or groups of species whose behav- from cloud caps mitigates moisture loss and provides a stable iour mimics that of a larger set of variables are useful moist environment suitable for the development and mainte- for their ability to convey information about environ- nance of montane rainforest. Notophyll vine forests (Webb mental change (Bohac 1999; Niemi & McDonald 1978), characteristic of low nutrient soils, dominate higher 2004; Trindade-Filho & Loyola 2011). Individual elevations and gradate into mesophyll forests (Webb 1978) at species may be used to detect environmental changes lower elevations. Some baseline information is available on the but, when community level changes are probable, sets vegetation, of which most is derived from a permanent plot of organisms are likely to be more powerful and useful maintained by the Commonwealth Scientific and Industrial (Kitching et al. 2000; Kitching & Ashton 2013). Inver- Research Organisation (CSIRO) (Graham 2006) located to the south of the Clarke Range on basaltic soils. Much of the tebrates are widely accepted as powerful indicators of northern section of the Clarke Range, however, has developed ecosystem states. Aquatic taxa such as Ephemeroptera, upon an extensive granitic landscape (early Miocene to Plecoptera and Trichoptera have been widely used Palaeocene) (Graham 2006). Few studies provide detail on with considerable success to assess stream quality and vegetation composition or structure for forests on these gra- environmental health of rivers (Blattenberger et al. nitic soils. Little if any information is available on the associ- 2000; Carignan & Villard 2002; Wright et al. 2007; ated invertebrates. EHMP 2008). In terrestrial ecosystems, Lepidoptera (moths and butterflies) and Coleoptera (beetles) are commonly employed as indicator groups to measure Study design environmental quality (Niemelä et al. 2000; Rainio & Niemelä 2003; Maleque et al. 2009; Gerlach et al. The methodology of this study follows those of the Investigating 2013). The present study examines elevation-related the Biodiversity of Soil and Canopy Arthropods (IBISCA) changes in a Queensland tropical rainforest in order Queensland project (Ashton et al. 2011; Kitching et al. 2011). to select statistically defined sets of night-flying The continuity in sampling techniques allows for uncompro- Lepidoptera (moths) that may be used to monitor mised comparisons of data between Eungella and previous future ecosystem level changes. studies (see Ashton et al. 2011; Ashton 2013).The comparisons drawn among these studies, uncompromised by the use of incompatible methodologies, contributes to the development of a more general understanding of ecosystem responses to eleva- METHODS tion and climate, and how these respond to changing climate. This study was carried out along an elevational gradient at Eungella National Park to investigate changes in moth Study site assemblages between 200 m asl and 1200 m asl. Sampling occurred among elevational bands at 200 m elevation inter- Eungella (21°S, 148°E), located 80 km west of Mackay on vals at 200 m asl, 400 m asl, 600 m asl, 800 m asl, 1000 m asl the Clarke Range, is the largest patch of remnant rainforest and 1200 m asl. Four plots spaced at least 500 m apart were between the Wet Tropics of far northern Queensland and the established within each elevational band (Fig. 1, see Appen- Macpherson Range and Tweed Caldera in the subtropical dix S1 for site coordinates). However, in contrast to the south-east of Queensland and north-eastern New South IBISCA Queensland project, the spatial positioning of the Wales. The rainforests of the Eungella massif present a con- plots within each elevational band were not placed in a line to tinuum ranging from lowland rainforest at about 200 m asl to account for spatial autocorrelation factors. montane rainforest above 1100 m asl. In contrast to the forests of the Wet Tropics and the Tweed Caldera, the rain- forest of Eungella have been little studied ecologically. Eungella’s