Pacioni C.,Murdoch University |
Wayne A.F.,Department of Environment and Conservation Perth |
Spencer P.B.S.,Murdoch University
Journal of Zoology | Year: 2011
A deep understanding of population structures and of the relationships among populations is fundamental to guarantee adequate management of endangered species. We used a molecular approach (12 microsatellite loci and mitochondrial DNA) to investigate these aspects in the woylie or brush-tailed bettong Bettongia penicillata ogilbyi. Four distinct indigenous populations were identified in this study (i.e. Dryandra woodland and Tutanning nature reserve in the wheatbelt region and two discrete populations in the Upper Warren in the south-west forests of Western Australia). Additionally, previously undisclosed modern and historical connections between these units became evident, such as the historical connection between populations at 150 km distance (Dryandra and Upper Warren) and the contemporary gene flow between the two populations in Upper Warren (up to 60 km). Genetic attributes of the four populations were analysed and the evidence of unique genetic material in each of these populations indicated that conservation effort should aim towards the preservation of all these units. Additionally, the lower genetic diversity of the woylie population in Tutanning nature reserve prompted the need for the investigation of factors that are limiting the demographic growth of this population. This study enhances not only our knowledge about the ecology of woylies but also the genetic consequences of habitat fragmentation and reiterates the strength and pertinence of molecular techniques in similar investigations. © 2010 The Authors.
Yates C.J.,Department of Environment and Conservation Perth |
Ladd P.G.,Murdoch University
Plant Ecology | Year: 2010
The fragmentation of mediterranean climate landscapes where fire is an important landscape process may lead to unsuitable fire regimes for many species, particularly rare species that occur as small isolated populations. We investigate the influence of fire interval on the persistence of population fragments of the endangered shrub Verticordia fimbrilepis Turcz. subsp. fimbrilepis in mediterranean climate south-west of Western Australia. We studied the population biology of the species over 5 years. While the species does recruit sporadically without fire this occurs only in years with above average rainfall, so fire seems to be the main environmental factor producing extensive recruitment. Transition matrix models were constructed to describe the shrub's population dynamics. As the species is killed by fire and relies on a seed bank stimulated to germinate by smoke, stochastic simulations to compare different fire frequencies on population viability were completed. Extinction risk increased with increasing average fire interval. Initial population size was also important, with the lowest extinction risk in the largest population. For populations in small reserves where fire is generally excluded, inevitable plant senescence will lead to local extirpation unless fires of suitable frequency can be used to stimulate regeneration. While a suitable fire regime reduces extinction risk small populations are still prone to extinction due to stochastic influences, and this will be exacerbated by a projected drying climate increasing rates of adult mortality and also seedling mortality in the post-fire environment. © UK Crown 2010.
McIlgorm A.,University of Wollongong |
Campbell H.F.,University of Queensland |
Rule M.J.,Department of Environment and Conservation Perth
Ocean and Coastal Management | Year: 2011
Oceans in the Asia-Pacific region are being impacted by increasing levels of marine debris, with many governments unaware of the extent that marine debris damages marine industries, the economy and the marine environment. We examine the economic costs associated with marine debris and present a simple marine debris cycle model to discuss the costs and benefits of prevention, clean-up and the benefits of using biodegradable materials. For the 21 economies of the Asia- Pacific rim we estimate that marine debris-related damage to marine industries costs US$1.26bn per annum in 2008 terms. Marine debris imposes an avoidable cost that can be reduced through policy implementation to economically optimal levels. Options to control debris, using regulations, technical intervention and market based instruments, may have a role. In this pollution policy area, additional economic cost data are required to inform governments on the most economical ways to control levels of marine debris. © 2011 Elsevier Ltd.
Poorter H.,Julich Research Center |
Niklas K.J.,Cornell University |
Reich P.B.,University of Minnesota |
Reich P.B.,University of Western Sydney |
And 5 more authors.
New Phytologist | Year: 2012
We quantified the biomass allocation patterns to leaves, stems and roots in vegetative plants, and how this is influenced by the growth environment, plant size, evolutionary history and competition. Dose-response curves of allocation were constructed by means of a meta-analysis from a wide array of experimental data. They show that the fraction of whole-plant mass represented by leaves (LMF) increases most strongly with nutrients and decreases most strongly with light. Correction for size-induced allocation patterns diminishes the LMF-response to light, but makes the effect of temperature on LMF more apparent. There is a clear phylogenetic effect on allocation, as eudicots invest relatively more than monocots in leaves, as do gymnosperms compared with woody angiosperms. Plants grown at high densities show a clear increase in the stem fraction. However, in most comparisons across species groups or environmental factors, the variation in LMF is smaller than the variation in one of the other components of the growth analysis equation: the leaf area:leaf mass ratio (SLA). In competitive situations, the stem mass fraction increases to a smaller extent than the specific stem length (stem length:stem mass). Thus, we conclude that plants generally are less able to adjust allocation than to alter organ morphology. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.
Coker D.J.,James Cook University |
Coker D.J.,Australian Institute of Marine Science |
Wilson S.K.,Department of Environment and Conservation Perth |
Wilson S.K.,University of Western Australia |
Pratchett M.S.,James Cook University
Reviews in Fish Biology and Fisheries | Year: 2014
Live corals are the key habitat forming organisms on coral reefs, contributing to both biological and physical structure. Understanding the importance of corals for reef fishes is, however, restricted to a few key families of fishes, whereas it is likely that a vast number of fish species will be adversely affected by the loss of live corals. This study used data from published literature together with independent field based surveys to quantify the range of reef fish species that use live coral habitats. A total of 320 species from 39 families use live coral habitats, accounting for approximately 8 % of all reef fishes. Many of the fishes reported to use live corals are from the families Pomacentridae (68 spp.) and Gobiidae (44 spp.) and most (66 %) are either planktivores or omnivores. 126 species of fish associate with corals as juveniles, although many of these fishes have no apparent affiliation with coral as adults, suggesting an ontogenetic shift in coral reliance. Collectively, reef fishes have been reported to use at least 93 species of coral, mainly from the genus Acropora and Porities and associate predominantly with branching growth forms. Some fish associate with a single coral species, whilst others can be found on more than 20 different species of coral indicating there is considerable variation in habitat specialisation among coral associated fish species. The large number of fishes that rely on coral highlights that habitat degradation and coral loss will have significant consequences for biodiversity and productivity of reef fish assemblages. © 2013 Springer Science+Business Media Dordrecht.