Summary People who live on the edges of protected areas may harvest timber to make their living f... more Summary People who live on the edges of protected areas may harvest timber to make their living from this natural forest product. Therefore, understanding timber consumption at the household level is critical for developing effective conservation policies. Previous studies have highlighted relationships between the consumption of forest products and socioeconomic status, but they have failed to examine timber consumption under cultural contexts. In this study, we interviewed 121 villagers to examine the socioeconomic profiles of timber consumers with regards to their indigenous culture in the buffer zones of Vietnam’s Bu Gia Map National Park. We found that indigenous identity, landownership, number of crops grown by villagers and proximity to markets are statistically significant for explaining the consumption of timber from natural forests. Given the high likelihood that most of this timber was collected illegally, we make several recommendations for forest managers on how to interact with villagers to improve park protection.
Marine and Freshwater Behaviour and Physiology, Dec 1, 2007
The intra- and interspecific agonistic behavior of Euastacus armatus and Cherax destructor from n... more The intra- and interspecific agonistic behavior of Euastacus armatus and Cherax destructor from northeastern Victoria were examined. While the agonistic patterns of E. armatus appeared similar to those shown by most crayfish, individuals of C. destructor execute an unusual, highly stylized cheliped “punch” behavior during strong interactions, along with the other behaviors seen in many species. Juvenile C. destructor exhibited
... BENJAMIN P. OLDROYD,' SUSAN H. LAWLER^ AND ROSS H. CROZIER' ^Depart... more ... BENJAMIN P. OLDROYD,' SUSAN H. LAWLER^ AND ROSS H. CROZIER' ^Department of Genetics and Human Variation, La Trobe University, Bundoora, Vic. ... Eucalyptus largiflorens, hollow, honey bee, nest site, Polytelis anthopeplus, regent parrot, Victoria. ...
ABSTRACT Honey-bees are widespread as feral animals in Australia. Their impact on Australian ecos... more ABSTRACT Honey-bees are widespread as feral animals in Australia. Their impact on Australian ecosystems is difficult to assess, but may include competition with native fauna for floral resources or nesting sites, or inadequate or inappropriate pollination of native flora. In this 3-year study we examined the demography of the feral bee population in the riparian woodland of Wyperfeld National Park in north-west Victoria. The population is very large but varied considerably in size (50–150 colonies/km2) during the study period (1992–1995). The expected colony lifespan for an established colony is 6.6 years, that for a founder colony (new swarm), 2.7 years. The population is expected to be stable if each colony produces 0.75 swarms per year, which is less than the number predicted on the basis of other studies (2–3 swarms/colony per year). Therefore, the population has considerable capacity for increase. Most colony deaths occurred in the summer, possibly due to high temperatures and lack of water. Colonies showed considerable spatial aggregation, agreeing with earlier findings. When all colonies were eradicated from two 5-ha sites, the average rate of re-occupation was 15 colonies/km2 per year. Ten swarms of commercial origin were released and were found to have similar survival rates to founder colonies. However, the feral population is self-sustaining, and does not require immigration from the domestic population.
Future climate change predictions indicate that there will be an increase in ambient air temperat... more Future climate change predictions indicate that there will be an increase in ambient air temperature. Increases in ambient air temperature will result in a corresponding increase in soil temperature. The consequences of further increases in soil temperature will potentially be detrimental for the soil seed bank of plants in terms of length of dormancy and viability of seeds. This experiment investigated the effect of different exposure temperatures and duration of exposure on the germination of semi-aquatic plant species. Seeds of four species (Alternanthera denticulata, Juncus usitatus, Persicaria lapathifolia and Persicaria prostrata) were exposed to temperatures ranging from 25 to 100°C for durations between 1 and 14 days, before being germinated in an incubator for 6 weeks. Germination occurred in all four species after exposure to temperatures ranging from 25 to 60°C. These temperatures appeared to promote germination as the temperature and duration of exposure increased. However, in P. lapathifolia and P. prostrata, the number of seeds germinating declined when exposed to 70°C and there was no germination for temperatures exceeding this. In contrast, A. denticulata and J. usitatus only began to decline when exposed to 80°C, with no germination at higher temperatures. These results suggest that soil temperatures exceeding potential threshold temperatures of 70 and 80°C will result in a decline in the number of seeds germinating and may potentially see a change in species distributions. As such soil temperatures are already being experienced throughout Australia, some species may already be close to their thermal threshold.
We sequenced approximately 500 base pairs of DNA from the 16S region of the mitochondrial genome ... more We sequenced approximately 500 base pairs of DNA from the 16S region of the mitochondrial genome to estimate relationships among the freshwater crayfish genera of Australia and New Zealand. In total, 35 sequences were obtained, representing 32 species and all 10 genera native to Australia and New Zealand. From these sequences, maximum likelihood, minimum evolution and parsimony estimates of phylogenetic relationships among the genera were obtained and compared with previous hypotheses concerning the relationships among the crayfish genera. Our results support the monophyly of each genus (except perhaps Euastacus) and the organisation of these genera into three major clades: the first clade contains the genera Engaeus, Tenuibranchiurus, Geocharax, Gramastacus, and Cherax; the second clade contains the genera Paranephrops, Parastacoides, Euastacus, and Astacopsis; and the third clade contains the genus Engaewa. We reject the ecological hypothesis of Riek for two major clades of crayfish species. Finally, we provide a checklist of the Australian and New Zealand species as they are currently recognised.
Remote communities alleviate economic hardship by renting their crops to others, and these transa... more Remote communities alleviate economic hardship by renting their crops to others, and these transactions are often informal and exploitative. Because farmland is an important income source for rural areas, understanding the participation in distress rentals of cashew nut farms is critical for sustainable development. Previous studies have highlighted relationships between socioeconomic factors and participation in land rentals but have failed to examine distress rentals under ethnic contexts. In this study, we interviewed 121 villagers to examine socioeconomic determinants of the participation in distress rentals of farmers with regard to their indigenous culture in two communes in Binh Phuoc province. We found that ethnic identity, land‐ownership, informal training in agriculture, family size, and proximity to markets are statistically significant in explaining the likelihood to participate in distress rentals. Based on these findings, we make several recommendations for how local governments can create better policies to ensure social justice.
An unusual population of freshwater crayfish of the genus Euastacus found in the East Buffalo Riv... more An unusual population of freshwater crayfish of the genus Euastacus found in the East Buffalo River, Victoria, is morphologically distinguishable from other populations, and in particular has a marbled or camouflage pattern on the carapace. The cheliped dactylar spine counts and the number of zygocardiac teeth anterior to the ventral ear of the zygocardiac ossicle (TAP) are somewhat reduced but these values overlap with the range of the most similar species (E. armatus). Genetic sequences from the CO1 and 16S mitochondrial DNA regions were also undertaken, and the results indicated that these animals may represent an aberrant population of E. armatus (the Murray Crayfish) or perhaps a hybrid between E. armatus and E. woiwuru, two species that are found downstream and upstream, respectively, of the population investigated. The conservation status of the population remains unclear. Decapoda, Parastacidae, mitochondrial DNA, Buffalo River, conservation, Murray Cray, hybrid. Street, Edney, Rowe & Lawler 214 Memoirs of the Queensland Museum | Nature 2010 55(1) the Gippsland spiny crayfish (Shull et al. 2005). Both E. armatus and E. woiwuru are found in the Buffalo River in northeast Victoria. In 2002 we visited Dandongadale, on the Buffalo River near the junction of the Rose River, in order to recollect Euastacus woiwuru that had first been collected at that locality by P. Horwitz in 1982 (Morgan 1986). When we searched the area this time we could only find E. armatus. We continued to search upstream and found an unusual population of crayfish at Schultz Track in 2002 with a marbled carapace (Fig. 1). Further searches of the Buffalo River were interrupted by the bushfires of 2003, which closed some roads for 18 months. When we were able to return to the site, it had been altered by bulldozers and the water was affected by heavy erosion and ash from the fire. We were unable to find any crayfish at that time. In 2006 the fires came again, with heavy fire-fighting taking place near Schultz Track. When the roads opened again in 2007, we were finally able to collect a number of crayfish at Schultz Track and upstream of the site. We were also thus able to determine that the marbled population of Euastacus at the Schultz Track site actually occurred at the boundary between E. armatus and E. woiwuru populations. The marbled Euastacus at Schultz Track have a distinctive colour pattern on the carapace (Fig. 1), and a few other characters that differ from the other spiny crayfish species in the river. We originally misidentified these crayfish as Euastacus crassus (Riek 1969) and included the DNA in a large phylogeny of Euastacus (specimen number KC2654 in Shull et al. 2005), however, its position on the phylogeny showed clearly that it was not E. crassus (Shull et al. 2005). The specimen was then sent to Dr John Short of the Queensland Museum, who said he believed it to be a new species (pers. com.). As such it was listed as an undescribed species in a recent review of the conservation status of Victorian freshwater crayfish (O’Brien 2007). For measures to be invoked toward the management of crayfish populations, species have to be recognised as threatened and in need of protection (Merrick 1997). The conservation status of the unknown crayfish at Schultz Track could not be clarified until its taxonomic status was resolved. Further collections were interrupted by road closures due to wild fires in 2003 and 2006. We were finally able to collect more individuals in 2007, and discovered that the site where we found the unusual population occurred on the species boundary between E. armatus and E. woiwuru. In this study we compare the unusual crayfish with other local Euastacus species using both morphological and genetic characters.
EarthSong Journal: Perspectives in Ecology, Spirituality and Education, 2013
In this article we are invited to think more deeply about our glib use of some words and the unde... more In this article we are invited to think more deeply about our glib use of some words and the underlying mysteries and miracles that lie embedded beneath them.
Summary People who live on the edges of protected areas may harvest timber to make their living f... more Summary People who live on the edges of protected areas may harvest timber to make their living from this natural forest product. Therefore, understanding timber consumption at the household level is critical for developing effective conservation policies. Previous studies have highlighted relationships between the consumption of forest products and socioeconomic status, but they have failed to examine timber consumption under cultural contexts. In this study, we interviewed 121 villagers to examine the socioeconomic profiles of timber consumers with regards to their indigenous culture in the buffer zones of Vietnam’s Bu Gia Map National Park. We found that indigenous identity, landownership, number of crops grown by villagers and proximity to markets are statistically significant for explaining the consumption of timber from natural forests. Given the high likelihood that most of this timber was collected illegally, we make several recommendations for forest managers on how to interact with villagers to improve park protection.
Marine and Freshwater Behaviour and Physiology, Dec 1, 2007
The intra- and interspecific agonistic behavior of Euastacus armatus and Cherax destructor from n... more The intra- and interspecific agonistic behavior of Euastacus armatus and Cherax destructor from northeastern Victoria were examined. While the agonistic patterns of E. armatus appeared similar to those shown by most crayfish, individuals of C. destructor execute an unusual, highly stylized cheliped “punch” behavior during strong interactions, along with the other behaviors seen in many species. Juvenile C. destructor exhibited
... BENJAMIN P. OLDROYD,' SUSAN H. LAWLER^ AND ROSS H. CROZIER' ^Depart... more ... BENJAMIN P. OLDROYD,' SUSAN H. LAWLER^ AND ROSS H. CROZIER' ^Department of Genetics and Human Variation, La Trobe University, Bundoora, Vic. ... Eucalyptus largiflorens, hollow, honey bee, nest site, Polytelis anthopeplus, regent parrot, Victoria. ...
ABSTRACT Honey-bees are widespread as feral animals in Australia. Their impact on Australian ecos... more ABSTRACT Honey-bees are widespread as feral animals in Australia. Their impact on Australian ecosystems is difficult to assess, but may include competition with native fauna for floral resources or nesting sites, or inadequate or inappropriate pollination of native flora. In this 3-year study we examined the demography of the feral bee population in the riparian woodland of Wyperfeld National Park in north-west Victoria. The population is very large but varied considerably in size (50–150 colonies/km2) during the study period (1992–1995). The expected colony lifespan for an established colony is 6.6 years, that for a founder colony (new swarm), 2.7 years. The population is expected to be stable if each colony produces 0.75 swarms per year, which is less than the number predicted on the basis of other studies (2–3 swarms/colony per year). Therefore, the population has considerable capacity for increase. Most colony deaths occurred in the summer, possibly due to high temperatures and lack of water. Colonies showed considerable spatial aggregation, agreeing with earlier findings. When all colonies were eradicated from two 5-ha sites, the average rate of re-occupation was 15 colonies/km2 per year. Ten swarms of commercial origin were released and were found to have similar survival rates to founder colonies. However, the feral population is self-sustaining, and does not require immigration from the domestic population.
Future climate change predictions indicate that there will be an increase in ambient air temperat... more Future climate change predictions indicate that there will be an increase in ambient air temperature. Increases in ambient air temperature will result in a corresponding increase in soil temperature. The consequences of further increases in soil temperature will potentially be detrimental for the soil seed bank of plants in terms of length of dormancy and viability of seeds. This experiment investigated the effect of different exposure temperatures and duration of exposure on the germination of semi-aquatic plant species. Seeds of four species (Alternanthera denticulata, Juncus usitatus, Persicaria lapathifolia and Persicaria prostrata) were exposed to temperatures ranging from 25 to 100°C for durations between 1 and 14 days, before being germinated in an incubator for 6 weeks. Germination occurred in all four species after exposure to temperatures ranging from 25 to 60°C. These temperatures appeared to promote germination as the temperature and duration of exposure increased. However, in P. lapathifolia and P. prostrata, the number of seeds germinating declined when exposed to 70°C and there was no germination for temperatures exceeding this. In contrast, A. denticulata and J. usitatus only began to decline when exposed to 80°C, with no germination at higher temperatures. These results suggest that soil temperatures exceeding potential threshold temperatures of 70 and 80°C will result in a decline in the number of seeds germinating and may potentially see a change in species distributions. As such soil temperatures are already being experienced throughout Australia, some species may already be close to their thermal threshold.
We sequenced approximately 500 base pairs of DNA from the 16S region of the mitochondrial genome ... more We sequenced approximately 500 base pairs of DNA from the 16S region of the mitochondrial genome to estimate relationships among the freshwater crayfish genera of Australia and New Zealand. In total, 35 sequences were obtained, representing 32 species and all 10 genera native to Australia and New Zealand. From these sequences, maximum likelihood, minimum evolution and parsimony estimates of phylogenetic relationships among the genera were obtained and compared with previous hypotheses concerning the relationships among the crayfish genera. Our results support the monophyly of each genus (except perhaps Euastacus) and the organisation of these genera into three major clades: the first clade contains the genera Engaeus, Tenuibranchiurus, Geocharax, Gramastacus, and Cherax; the second clade contains the genera Paranephrops, Parastacoides, Euastacus, and Astacopsis; and the third clade contains the genus Engaewa. We reject the ecological hypothesis of Riek for two major clades of crayfish species. Finally, we provide a checklist of the Australian and New Zealand species as they are currently recognised.
Remote communities alleviate economic hardship by renting their crops to others, and these transa... more Remote communities alleviate economic hardship by renting their crops to others, and these transactions are often informal and exploitative. Because farmland is an important income source for rural areas, understanding the participation in distress rentals of cashew nut farms is critical for sustainable development. Previous studies have highlighted relationships between socioeconomic factors and participation in land rentals but have failed to examine distress rentals under ethnic contexts. In this study, we interviewed 121 villagers to examine socioeconomic determinants of the participation in distress rentals of farmers with regard to their indigenous culture in two communes in Binh Phuoc province. We found that ethnic identity, land‐ownership, informal training in agriculture, family size, and proximity to markets are statistically significant in explaining the likelihood to participate in distress rentals. Based on these findings, we make several recommendations for how local governments can create better policies to ensure social justice.
An unusual population of freshwater crayfish of the genus Euastacus found in the East Buffalo Riv... more An unusual population of freshwater crayfish of the genus Euastacus found in the East Buffalo River, Victoria, is morphologically distinguishable from other populations, and in particular has a marbled or camouflage pattern on the carapace. The cheliped dactylar spine counts and the number of zygocardiac teeth anterior to the ventral ear of the zygocardiac ossicle (TAP) are somewhat reduced but these values overlap with the range of the most similar species (E. armatus). Genetic sequences from the CO1 and 16S mitochondrial DNA regions were also undertaken, and the results indicated that these animals may represent an aberrant population of E. armatus (the Murray Crayfish) or perhaps a hybrid between E. armatus and E. woiwuru, two species that are found downstream and upstream, respectively, of the population investigated. The conservation status of the population remains unclear. Decapoda, Parastacidae, mitochondrial DNA, Buffalo River, conservation, Murray Cray, hybrid. Street, Edney, Rowe & Lawler 214 Memoirs of the Queensland Museum | Nature 2010 55(1) the Gippsland spiny crayfish (Shull et al. 2005). Both E. armatus and E. woiwuru are found in the Buffalo River in northeast Victoria. In 2002 we visited Dandongadale, on the Buffalo River near the junction of the Rose River, in order to recollect Euastacus woiwuru that had first been collected at that locality by P. Horwitz in 1982 (Morgan 1986). When we searched the area this time we could only find E. armatus. We continued to search upstream and found an unusual population of crayfish at Schultz Track in 2002 with a marbled carapace (Fig. 1). Further searches of the Buffalo River were interrupted by the bushfires of 2003, which closed some roads for 18 months. When we were able to return to the site, it had been altered by bulldozers and the water was affected by heavy erosion and ash from the fire. We were unable to find any crayfish at that time. In 2006 the fires came again, with heavy fire-fighting taking place near Schultz Track. When the roads opened again in 2007, we were finally able to collect a number of crayfish at Schultz Track and upstream of the site. We were also thus able to determine that the marbled population of Euastacus at the Schultz Track site actually occurred at the boundary between E. armatus and E. woiwuru populations. The marbled Euastacus at Schultz Track have a distinctive colour pattern on the carapace (Fig. 1), and a few other characters that differ from the other spiny crayfish species in the river. We originally misidentified these crayfish as Euastacus crassus (Riek 1969) and included the DNA in a large phylogeny of Euastacus (specimen number KC2654 in Shull et al. 2005), however, its position on the phylogeny showed clearly that it was not E. crassus (Shull et al. 2005). The specimen was then sent to Dr John Short of the Queensland Museum, who said he believed it to be a new species (pers. com.). As such it was listed as an undescribed species in a recent review of the conservation status of Victorian freshwater crayfish (O’Brien 2007). For measures to be invoked toward the management of crayfish populations, species have to be recognised as threatened and in need of protection (Merrick 1997). The conservation status of the unknown crayfish at Schultz Track could not be clarified until its taxonomic status was resolved. Further collections were interrupted by road closures due to wild fires in 2003 and 2006. We were finally able to collect more individuals in 2007, and discovered that the site where we found the unusual population occurred on the species boundary between E. armatus and E. woiwuru. In this study we compare the unusual crayfish with other local Euastacus species using both morphological and genetic characters.
EarthSong Journal: Perspectives in Ecology, Spirituality and Education, 2013
In this article we are invited to think more deeply about our glib use of some words and the unde... more In this article we are invited to think more deeply about our glib use of some words and the underlying mysteries and miracles that lie embedded beneath them.
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Papers by Susan Lawler