Long-term recovery from fire by a population of honey possums (Tarsipes rostratus) in the extreme south-west of Western Australia

2017 ◽  
Vol 65 (1) ◽  
pp. 1 ◽  
Author(s):  
S. D. Bradshaw ◽  
F. J. Bradshaw

The impact of two fires, six years apart, on the long-term recovery of a population of honey possums (Tarsipes rostratus) in the extreme south-west of Western Australia was documented over a 23-year period. Recovery was relatively rapid after the first fire, with catch rates reaching 78% of precatch levels within six years, but was much slower following the second fire in April 1999. Regression analysis estimates that full recovery to prefire catch rates and densities would take 25.6 years. The spread of Phytophthora cinnamomi (dieback) throughout the study area has severely impacted Banksia ilicifolia trees, which are the honey possums’ primary food source, and the impact has been greater in the burnt than unburnt areas. Analysis of catch-per-unit-effort and density of individual honey possums over the whole 29-year period of the study shows that numbers have not declined in the long-unburnt southern area of the study site, despite the spread of dieback and loss of banksia trees. The data are discussed in relation to the impact of fire on other vertebrate species that have specific habitat requirements. Given predictions of increasing fire frequencies due to climate change and an increased utilisation of prescribed burning to protect human life and property, it is imperative that management of areas harbouring honey possums be protected from too-frequent fire if this iconic species is to persist.

2003 ◽  
Vol 54 (1) ◽  
pp. 39 ◽  
Author(s):  
K. Hutchings ◽  
S. J. Lamberth

Current South African government policy aims to create more equitable access to marine resources and there is pressure to increase the inshore gill-net fishing effort. At present, the gill-net fishery in the Western Cape is confined to the cool temperate west coast. In order to ascertain the potential catch if the fishery was to expand along the warm temperate south-west coast, a program of experimental netting was conducted. Estuarine and coastal marine sites were sampled bimonthly, using a range of commercial gill-nets (44–178 mm stretch-mesh). Although the target species, Liza richardsonii, dominated the catches, at least 33 of the by-catch species caught were also targeted by the commercial or recreational line-fish sectors. The number of species captured and the line-fish (by-catch) catch per unit effort (CPUE) were greatest in areas currently closed to the commercial gill-net fishery. Multivariate analysis indicated significant differences in catch rates and composition between exploited west coast and unexploited south-west coast sites. A combination of natural biogeographical trends and the impact of over 100 years of commercial gill-netting on the west coast are the likely causes of these differences. A spatial expansion of the gill-net fishery could have a detrimental impact on overexploited line-fish stocks and lead to increased user conflict.


2018 ◽  
Vol 27 (10) ◽  
pp. 643 ◽  
Author(s):  
S. D. Bradshaw ◽  
K. W. Dixon ◽  
H. Lambers ◽  
A. T. Cross ◽  
J. Bailey ◽  
...  

Wildfires are expected to increase worldwide both in frequency and intensity owing to global warming, but are likely to vary geographically. This is of particular concern in the five mediterranean regions of the world that are all biodiversity hotspots with extraordinary plant and animal diversity that may be impacted by deliberately imposed fire. Wildland managers attempt to reduce the impact and mitigate the outcomes of wildfires on human assets and biodiversity by the use of prescribed burning. The response that we must ‘fight fire with fire’ is understandable, perceived as reducing the flammability of wildlands in fire-prone regions and lessening the impact of wildfires. The long-term impact on biodiversity is, however, less clear. The practice of prescribed burning has been in place and monitored in south-western Australia for 50 years, longer and more intensively than in most other mediterranean ecosystems. The present target is for 200 000 ha burned each year in this biodiversity hotspot. Published studies on the impact of this burning on infrastructure protection and on biodiversity are here used to understand the protective capacity of the practice and to foreshadow its possible long-term ecological impact across all mediterranean ecosystems.


2004 ◽  
Vol 52 (4) ◽  
pp. 435 ◽  
Author(s):  
B. L. Shearer ◽  
C. E. Crane ◽  
A. Cochrane

This study compares, for the first time, variation in estimates of susceptibility of native flora to Phytophthora cinnamomi Rands among four databases and proposes an estimate of the proportion of the flora of the South-West Botanical Province of Western Australia that is susceptible to the pathogen. Estimates of the susceptibility of south-western native flora to P. cinnamomi infection were obtained from databases for Banksia woodland of the Swan Coastal Plain, jarrah (Eucalyptus marginata Donn. ex Smith) forest, the Stirling Range National Park and Rare and Threatened Flora of Western Australia. For the woodland, forest and national park databases, hosts were naturally infected in uncontrolled diverse natural environments. In contrast, threatened flora were artificially inoculated in a shadehouse environment. Considerable variation occurred within taxonomic units, making occurrence within family and genus poor predictors of species susceptibility. Identification of intra-specific resistance suggests that P. cinnamomi could be having a strong selection pressure on some threatened flora at infested sites and the populations could shift to more resistant types. Similar estimates of the proportion of species susceptible to P. cinnamomi among the databases from the wide range of environments suggests that a realistic estimate of species susceptibility to P. cinnamomi infection in the south-western region has been obtained. The mean of 40% susceptible and 14% highly susceptible equates to 2284 and 800 species of the 5710 described plant species in the South-West Botanical Province susceptible and highly susceptible to P. cinnamomi, respectively. Such estimates are important for determining the cost of disease to conservation values and for prioritising disease importance and research priorities. P. cinnamomi in south-western Australia is an unparalleled example of an introduced pathogen with a wide host range causing immense irreversible damage to unique, diverse but mainly susceptible plant communities.


2007 ◽  
Vol 55 (3) ◽  
pp. 225 ◽  
Author(s):  
B. L. Shearer ◽  
C. E. Crane ◽  
S. Barrett ◽  
A. Cochrane

The invasive soilborne plant pathogen Phytophthora cinnamomi Rands is a major threatening process in the South-west Botanical Province of Western Australia, an internationally recognised biodiversity hotspot. Comparatively recent introduction of P. cinnamomi into native plant communities of the South-west Botanical Province of Western Australia since the early 1900s has caused great irreversible damage and altered successional change to a wide range of unique, diverse and mainly susceptible plant communities. The cost of P. cinnamomi infestation to community values is illustrated by examination of direct (mortality curves, changes in vegetation cover) and indirect impacts on biodiversity and ecosystem dynamics, the proportion of Threatened Ecological Communities infested, Declared Rare Flora either directly or indirectly threatened by infestation and estimates of the proportion of the native flora of the South-west Botanical Province susceptible to the pathogen. While direct impacts of P. cinnamomi have been poorly documented in the South-west Botanical Province, even less attention has been given to indirect impact where destruction of the habitat by the pathogen affects taxa not directly affected by infection. Current poor understanding and quantification of indirect impacts of P. cinnamomi through habitat destruction results in an underestimation of the true impact of the pathogen on the flora of the South-west Botanical Province. Considerable variation of susceptibility to P. cinnamomi among and within families of threatened flora and responses of taxa within the genus Lambertia show how classification within family and genus are poor predictors of species susceptibility. Within apparently susceptible plant species, individuals are resistant to P. cinnamomi infection. Intra-specific variation in susceptibility can be utilised in the long-term management of threatened flora populations and needs to be a high research priority. Current control strategies for conservation of flora threatened by P. cinnamomi integrate hygiene and ex situ conservation with disease control using fungicide. Application of the fungicide phosphite has proven effective in slowing progress of P. cinnamomi in infested, threatened communities. However, variation in plant species responses to phosphite application is a major factor influencing effective control of P. cinnamomi in native communities. A greater understanding of the mechanisms of action of phosphite in plant species showing different responses to the fungicide may provide options for prescription modification to increase phosphite effectiveness in a range of plant species. The range of responses to P. cinnamomi infection and phosphite application described for Lambertia taxa suggests that the genus would make an ideal model system to elucidate the mechanisms of resistance to P. cinnamomi and the effectiveness of phosphite against the pathogen.


2007 ◽  
Vol 55 (2) ◽  
pp. 107 ◽  
Author(s):  
Michael D. Craig ◽  
Mark J. Garkaklis ◽  
Giles E. St J. Hardy ◽  
Andrew H. Grigg ◽  
Carl D. Grant ◽  
...  

Forest areas restored after mining typically take decades, or longer, before they resemble the original vegetation community. Understanding how fauna succession varies with plant succession requires detailed knowledge of an animal’s ecology. Knowledge of an animal’s ecology can also be used to predict faunal responses to management manipulations and enable techniques to be developed that accelerate the return of fauna to restored sites. We radio-tracked western bearded dragons (Pogona minor) in a mix of unmined forest sites and sites restored after bauxite mining, in the jarrah forest of south-west Western Australia, to determine critical resources and important microhabitats for dragons. Dragons were generalists – utilising a range of microhabitats – and adaptable, adjusting their microhabitat use depending on availability. Individuals also differed significantly in their microhabitat use and did not appear to have a defined home range. We concluded that the species would rapidly recolonise restored sites and that no modifications to current restoration practices were required to accelerate their return. Prescribed burning of restored areas could negatively affect this species but the effect would be short-term (<2 years). The approach used in this study could be used to develop management prescriptions that accelerate the return of late-successional species to restored sites.


Author(s):  
José Carlos Báez ◽  
David Macías ◽  
Juan Antonio Camiñas ◽  
José María Ortiz de Urbina ◽  
Salvador García-Barcelona ◽  
...  

Fisheries by-catch is considered to be a major threat to loggerhead turtles in the Mediterranean Sea. Technical differences in both gear configurations (e.g. hook and bait type) and fisheries operations carried out by the Spanish Mediterranean surface longline fleet could have an effect on by-catch rates and size selectivity. The aim of the present study was to test the differences in by-catch per unit effort and body size of loggerhead sea turtles caught using different gear types in the Mediterranean surface longline fishery. Our results suggest that differences in the gear type used have an effect on catch rates and size selectivity. Thus, surface longliners targeting albacore (LLALB) using smaller hooks tend to capture smaller loggerheads but have the highest by-catch per unit of effort (BPUE), whereas other longlines, such as surface longliners targeting bluefin tuna (LLJAP) and traditional surface longliners targeting swordfish (LLHB), using larger hooks tend to select the larger animals; moreover, LLHB had the lowest BPUE. Disproportionate rates of fisheries-induced mortality on certain size/age-classes can differentially affect sea turtle populations, as each sea turtle age-class contributes differently to current and future reproduction. Thus, fisheries management should not only be focusing on preserving the large juvenile and mature turtles, but also on reducing the total by-catch. Thus, we recommend encouraging the use of LLHB versus other surface gears. We suggest that it is very important to take into account the gear type (and its particular catch rates) when making inferences about the impact of longline fisheries on sea turtle populations.


2014 ◽  
Vol 41 (2) ◽  
pp. 117 ◽  
Author(s):  
Shannon J. Dundas ◽  
Peter J. Adams ◽  
Patricia A. Fleming

Context In Western Australia, baits containing 1080 poison are widely used to control the red fox (Vulpes vulpes) for fauna conservation. Despite long-term (15–17 years) baiting programs, bait uptake by target and non-target species is largely unknown, but affects baiting efficacy. Aims We examined bait uptake of 1080-poisoned fox baits laid according to current practice at seven riparian sites in the northern jarrah forest (of south-west Western Australia). There, intensive baiting regimes have been implemented for the protection of quokka (Setonix brachyurus) populations. Methods Over 9 months, 299 Probait® baits were monitored regularly to determine their persistence, and, at 142 of these, Reconyx HC500 remote cameras were used to identify the species taking baits. To compare bait uptake with species presence at these sites, we calculated an activity index for each species from the number of passes of animals in front of the cameras. Key results The species taking baits was identified for 100 of the baits monitored with cameras, and, because of multiple species taking baits, 130 bait take incidents were recorded in total. The fate of 40 of the baits was not discernible and two baits were not removed. In all, 99% of baits monitored by cameras were taken by non-target species and quokkas took 48% of them. The majority of baits (62% of the total 299 monitored) were taken before or on the first night of deployment, and 95% of baits had been taken within 7 days. With the exception of feral pigs, which took more baits than predicted from their activity index at these sites, baits were taken in proportion to the activity index of species. Foxes were present at four of the seven sites, but only one fox was observed taking a bait. Conclusions The high level of uptake of baits by non-target animals reflects their diversity and abundance at these sites, but also significantly reduces the availability of baits to control foxes. Implications Strategies to reduce non-target bait uptake and increase bait availability for foxes are required.


2019 ◽  
Vol 67 (3) ◽  
pp. 218
Author(s):  
Melissa A. Millar ◽  
David J. Coates ◽  
Margaret Byrne ◽  
J. Dale Roberts

An increasingly important practical application of the analysis of spatial genetic structure and life history traits of plant species is to aid the design of seed sourcing scenarios that provide for long-term successful restoration. Despite this, there are few practical recommendations on how to use empirical knowledge of genetic structure and life history traits to design appropriate seed sourcing regimes and planting designs. We identified potential divergent lineages within species as an important first step in determining appropriate areas in which to source seeds. We then used a modelling approach for restoration based on patterns of genetic structure and life history traits that affect demography, dispersal and gene flow to inform the impact of number and spatial positioning of founder individuals, as well as different seed sourcing scenarios, on population growth and the initial capture and long-term maintenance of genetic diversity for restored populations. The approach is illustrated using datasets for four perennial plant species associated with the Banded Iron Formations of the semiarid midwest region of Western Australia. The approach can be tailored to any restoration site and applied to a range of species with differing patterns of genetic structure and differing life history traits.


2001 ◽  
Vol 49 (6) ◽  
pp. 761 ◽  
Author(s):  
K. M. Tynan ◽  
C. J. Wilkinson ◽  
J. M. Holmes ◽  
B. Dell ◽  
I. J. Colquhoun ◽  
...  

This study examined the ability of foliar applications of the fungicide phosphite to contain colonisation of Phytophthora cinnamomi in a range of plant species growing in natural plant communities in the northern sandplain and jarrah (Eucalyptus marginata) forest of south-western Australia. Wound inoculation of plant stems with P. cinnamomi was used to determine the efficacy of phosphite over time after application. Colonisation by P. cinnamomi was reduced for 5–24 months after phosphite was applied, depending on the concentration of phosphite used, plant species treated and the time of phosphite application. Plant species within and between plant communities varied considerably in their ability to take up and retain phosphite in inoculated stems and in the in planta concentrations of phosphite required to contain P. cinnamomi. As spray application rates of phosphite increased from 5 to 20 g L–1, stem tissue concentrations increased, as did the ability of a plant species to contain P. cinnamomi. However, at application rates of phosphite above 5 g L–1 phytotoxicity symptoms were obvious in most species, with some plants being killed. So, despite 10 and 20 g L–1 of phosphite being more effective and persistent in controlling P. cinnamomi, these rates are not recommended for application to the plant species studied. The results of this study indicate that foliar application of phosphite has considerable potential in reducing the impact of P. cinnamomi in native plant communities in the short-term. However, in order to maintain adequate control, phosphite should be sprayed every 6–12 months, depending on the species and/or plant community.


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