Search

A key factor influencing wildlife responses to human activity is the degree to which animals have been previously exposed to human stimuli. On subantarctic Macquarie Island, gentoo penguins Pygoscelis papua breed in areas of high and low human activity (on and off-station, respectively). We investigated the behaviour and breeding success of gentoo penguins on and off-station by, a) comparing the behavioural responses of guarding gentoos before, during and after exposure to standardised pedestrian approaches, and b) employing an observational study to determine how human activity may have contributed to within-season breeding success in light of other environmental and site variables. Behavioural responses to pedestrian visitation by gentoos off-station were significantly stronger than those of birds breeding on-station. However, no relationship was found between pedestrian activity and breeding success off-station. Breeding success was, however, positively related to colony size, and negatively related to the activity of other penguins, the number of nearby southern elephant seal Mirounga leonina harems and the location of colonies within short grassland. On-station, breeding success was amongst the highest recorded for that season. Habituation, predator exclusion and the relevance of these findings for management are discussed.

Located in the Southern Ocean 1500 km SSE of Tasmania, Macquarie Island is a remote and isolated island located roughly half-way between Australia and the Antarctic continent. This sub-Antarctic island is only 34 km long and up to 5 km wide with a land area of 12.785 ha. Because it is situated in the path of the 'Furious Fifties', the winds that circle the high southern latitudes, on average there are over 300 days of precipitation a year. Macquarie Island lies just north of the Antarctic Convergence zone where cold Antarctic waters mix with relatively wanner northern water. This results in a rough ocean, cold mists, sea-fogs and strong average wind speeds. Steep rocky beaches rise sharply to an undulating plateau roughly 100-300 m above sea level, with the highest point heing Mt Hamilton (433 m). These extreme sub-Antarctic environmental conditions are key factors in the overall distribution and abundance of island flora and fauna. Macqueric Island is home to an abundant and diverse array of wildlife. Approximately, 3.5 million seabirds arrive annually to breed and moult. Most of these visiting seabirds are penguins including 850,000 endemic royal penguins, over 100,000 breeding pairs of king penguins, 5000 breeding pairs of gentoo penguins and rockhopper penguins. Other seabirds include the endemic king cormorant, skuas and four albatross species. Of particular importance are the 15 pairs of the endangered wandering albatross. Four species of seal breed on Macquarie Island, including Antarctic fur seals. sub-Antarctic fur seals, New Zealand fur seals and one-seventh of the world's population of elephant seals (80,000) (PWS, 2003), The limited land mass in the Southern Ocean makes this a particularly important location for birds, seals and sub-Antarctic vegetation. Macquarie Island is also one of the earliest sites occupied by Europeans in Australia. Sites of historical interest from fur seal, elephant seal and penguin oil gathering work gangs are scattered around

Leaf mass per area (MA) is a central ecological trait that is intercorrelated with leaf life span, photosynthetic rate, nutrient concentration, and palatability to herbivores. These coordinated variables form a globally convergent leaf economics spectrum, which represents a general continuum running from rapid resource acquisition to maximized resource retention. Leaf economics are little studied in ancient ecosystems because they cannot be directly measured from leaf fossils. Here we use a large extant data set (65 sites; 667 species-site pairs) to develop a new, easily measured scaling relationship between petiole width and leafmass, normalized for leaf area; this enablesMA estimation for fossil leaves from petiole width and leaf area, two variables that are commonly measurable in leaf compression floras. The calibration data are restricted to woody angiosperms exclusive of monocots, but a preliminary data set (25 species) suggests that broad-leaved gymnosperms exhibit a similar scaling. Application to two well-studied, classic Eocene floras demonstrates thatMA can be quantified in fossil assemblages. First, our results are consistent with predictions from paleobotanical and paleoclimatic studies of these floras. We found exclusively low-MA species from Republic (Washington, U.S.A., 49 Ma), a humid, warm-temperate flora with a strong deciduous component among the angiosperms, and a wide MA range in a seasonally dry, warm-temperate flora from the Green River Formation at Bonanza (Utah, U.S.A, 47 Ma), presumed to comprise a mix of short and long leaf life spans. Second, reconstructed MA in the fossil species is negatively correlated with levels of insect herbivory, whether measured as the proportion of leaves with insect damage, the proportion of leaf area removed by herbivores, or the diversity of insect-damage morphotypes. These correlations are consistent with herbivory observations in extant floras and they reflect fundamental trade-offs in plant-herbivore assoc

Located in the Southern Ocean 1500 km SSE of Tasmania, Macquarie Island is a remote and isolated island located roughly half-way between Australia and the Antarctic continent. This sub-Antarctic island is only 34 km long and up to 5 km wide with a land area of 12.785 ha. Because it is situated in the path of the 'Furious Fifties', the winds that circle the high southern latitudes, on average there are over 300 days of precipitation a year. Macquarie Island lies just north of the Antarctic Convergence zone where cold Antarctic waters mix with relatively wanner northern water. This results in a rough ocean, cold mists, sea-fogs and strong average wind speeds. Steep rocky beaches rise sharply to an undulating plateau roughly 100-300 m above sea level, with the highest point heing Mt Hamilton (433 m). These extreme sub-Antarctic environmental conditions are key factors in the overall distribution and abundance of island flora and fauna. Macqueric Island is home to an abundant and diverse array of wildlife. Approximately, 3.5 million seabirds arrive annually to breed and moult. Most of these visiting seabirds are penguins including 850,000 endemic royal penguins, over 100,000 breeding pairs of king penguins, 5000 breeding pairs of gentoo penguins and rockhopper penguins. Other seabirds include the endemic king cormorant, skuas and four albatross species. Of particular importance are the 15 pairs of the endangered wandering albatross. Four species of seal breed on Macquarie Island, including Antarctic fur seals. sub-Antarctic fur seals, New Zealand fur seals and one-seventh of the world's population of elephant seals (80,000) (PWS, 2003), The limited land mass in the Southern Ocean makes this a particularly important location for birds, seals and sub-Antarctic vegetation. Macquarie Island is also one of the earliest sites occupied by Europeans in Australia. Sites of historical interest from fur seal, elephant seal and penguin oil gathering work gangs are scattered around

A key factor influencing wildlife responses to human activity is the degree to which animals have been previously exposed to human stimuli. On subantarctic Macquarie Island, gentoo penguins Pygoscelis papua breed in areas of high and low human activity (on and off-station, respectively). We investigated the behaviour and breeding success of gentoo penguins on and off-station by, a) comparing the behavioural responses of guarding gentoos before, during and after exposure to standardised pedestrian approaches, and b) employing an observational study to determine how human activity may have contributed to within-season breeding success in light of other environmental and site variables. Behavioural responses to pedestrian visitation by gentoos off-station were significantly stronger than those of birds breeding on-station. However, no relationship was found between pedestrian activity and breeding success off-station. Breeding success was, however, positively related to colony size, and negatively related to the activity of other penguins, the number of nearby southern elephant seal Mirounga leonina harems and the location of colonies within short grassland. On-station, breeding success was amongst the highest recorded for that season. Habituation, predator exclusion and the relevance of these findings for management are discussed.

Minimum approach distance guidelines are common tools to maintain a buffer between breeding seabirds and human activity, with the goal of mitigating potentially harmful impacts from these interactions. We employed an experimental design to measure the heart rate and behaviour of Royal penguins on Macquarie Island, Australia, in response to a single pedestrian visit using the current recommended approach distance of 5 m for visitors. Penguins showed increased heart rate (1.23 times average resting heart rate) and vigilance (six-fold increase), suggested to be a precursor to a flight or fight response, however, no penguins fled their nests. These responses were significantly greater than observed during Subantarctic skua overflights, suggesting incubating Royal penguins viewed a single pedestrian at 5 m as a greater threat than a predator overflight. Single persons using the current minimum approach guideline when visiting incubating Royal penguins appear unlikely to elicit responses considered greater than minor or transitory, consistent with activities that are considered acceptable by current management arrangements on Macquarie Island. However, applying this guideline requires caution because the cumulative impacts of visitation are unknown and greater responses may occur with larger group sizes or during different breeding phases. We consider minimum approach distance guidelines should be based on the separation distance necessary to allow animals to undertake normal activity, rather than on the distance people can approach wildlife before the animals flee.

Minimum approach distance guidelines are common tools to maintain a buffer between breeding seabirds and human activity, with the goal of mitigating potentially harmful impacts from these interactions. We employed an experimental design to measure the heart rate and behaviour of Royal penguins on Macquarie Island, Australia, in response to a single pedestrian visit using the current recommended approach distance of 5 m for visitors. Penguins showed increased heart rate (1.23 times average resting heart rate) and vigilance (six-fold increase), suggested to be a precursor to a flight or fight response, however, no penguins fled their nests. These responses were significantly greater than observed during Subantarctic skua overflights, suggesting incubating Royal penguins viewed a single pedestrian at 5 m as a greater threat than a predator overflight. Single persons using the current minimum approach guideline when visiting incubating Royal penguins appear unlikely to elicit responses considered greater than minor or transitory, consistent with activities that are considered acceptable by current management arrangements on Macquarie Island. However, applying this guideline requires caution because the cumulative impacts of visitation are unknown and greater responses may occur with larger group sizes or during different breeding phases. We consider minimum approach distance guidelines should be based on the separation distance necessary to allow animals to undertake normal activity, rather than on the distance people can approach wildlife before the animals flee.

Leaf mass per area (MA) is a central ecological trait that is intercorrelated with leaf life span, photosynthetic rate, nutrient concentration, and palatability to herbivores. These coordinated variables form a globally convergent leaf economics spectrum, which represents a general continuum running from rapid resource acquisition to maximized resource retention. Leaf economics are little studied in ancient ecosystems because they cannot be directly measured from leaf fossils. Here we use a large extant data set (65 sites; 667 species-site pairs) to develop a new, easily measured scaling relationship between petiole width and leafmass, normalized for leaf area; this enablesMA estimation for fossil leaves from petiole width and leaf area, two variables that are commonly measurable in leaf compression floras. The calibration data are restricted to woody angiosperms exclusive of monocots, but a preliminary data set (25 species) suggests that broad-leaved gymnosperms exhibit a similar scaling. Application to two well-studied, classic Eocene floras demonstrates thatMA can be quantified in fossil assemblages. First, our results are consistent with predictions from paleobotanical and paleoclimatic studies of these floras. We found exclusively low-MA species from Republic (Washington, U.S.A., 49 Ma), a humid, warm-temperate flora with a strong deciduous component among the angiosperms, and a wide MA range in a seasonally dry, warm-temperate flora from the Green River Formation at Bonanza (Utah, U.S.A, 47 Ma), presumed to comprise a mix of short and long leaf life spans. Second, reconstructed MA in the fossil species is negatively correlated with levels of insect herbivory, whether measured as the proportion of leaves with insect damage, the proportion of leaf area removed by herbivores, or the diversity of insect-damage morphotypes. These correlations are consistent with herbivory observations in extant floras and they reflect fundamental trade-offs in plant-herbivore assoc

Minimum approach distance guidelines are common tools to maintain a buffer between breeding seabirds and human activity, with the goal of mitigating potentially harmful impacts from these interactions. We employed an experimental design to measure the heart rate and behaviour of Royal penguins on Macquarie Island, Australia, in response to a single pedestrian visit using the current recommended approach distance of 5 m for visitors. Penguins showed increased heart rate (1.23 times average resting heart rate) and vigilance (six-fold increase), suggested to be a precursor to a flight or fight response, however, no penguins fled their nests. These responses were significantly greater than observed during Subantarctic skua overflights, suggesting incubating Royal penguins viewed a single pedestrian at 5 m as a greater threat than a predator overflight. Single persons using the current minimum approach guideline when visiting incubating Royal penguins appear unlikely to elicit responses considered greater than minor or transitory, consistent with activities that are considered acceptable by current management arrangements on Macquarie Island. However, applying this guideline requires caution because the cumulative impacts of visitation are unknown and greater responses may occur with larger group sizes or during different breeding phases. We consider minimum approach distance guidelines should be based on the separation distance necessary to allow animals to undertake normal activity, rather than on the distance people can approach wildlife before the animals flee.