Ben J. FrenchLynda D. PriorChristopher N. JohnsonAndry Sculthorpe...
e12620.1-e12620.14页
查看更多>>摘要：Temperate grassy woodlands were once widespread in southeast Australia and were shaped by fire regimes imposed by Indigenous peoples. Today, they persist as scattered fragments in matrices of highly modified farmland, where fire is rare and eucalypt trees are in decline. Returning fire to these fragments is a suggested approach to reduce fuels and stimulate eucalypt recruitment. We implemented a single round of small, low-intensity surface fires in a woodland fragment in the Tasmanian Midlands and assessed adult eucalypt mortality and juvenile recruitment. The fires were set during mild fire weather, were tended by 4–15 people, and fire-fighting vehicles were used to extinguish burning trees. Still, the fires killed 7% of adult eucalypts (18 trees), mostly due to cambial girdling which occurred where burning litter and coarse woody debris at the base of the trees initiated smouldering fires in thick bark on the lower trunks. Seedling recruitment was restricted to ash beds near trees with viable seed crops. Seedlings survived only if protected from mammalian herbivores. Herbivore protection also increased the growth of lignotuberous sprouts after fire. Our findings demonstrate that eucalypt trees in degraded woodland fragments may be vulnerable to low-intensity surface fire. We make recommendations as to how managers may burn woodland fragments in ways that avoid killing eucalypt trees and enhance postfire recruitment, enabling transition to more sustainable fire regimes.
Sebastien ComteAndrew J. BengsenThomas Botterill-JamesChris Brausch...
e70001.1-e70001.13页
查看更多>>摘要：Non-native deer populations are increasing in many parts of the world. Recreational hunting has commonly been advocated as a method for reducing deer population densities on private land, but there have been few robust evaluations of its effectiveness. We quantified the impacts of recreational hunting on a population of non-native fallow deer (Dama dama) on a private conservation reserve in Tasmania, Australia. We used a grid of 64 motion-sensitive cameras to estimate seasonal deer population density for three consecutive years. Recreational hunters recorded their hunting effort (date and duration of hunts), deer seen, and deer killed, and used a GPS to record where they hunted. Throughout the three-year period, deer density remained between 3.95 and 4.96 deer per km2, well above the mean 2.7 deer per km2 estimated for Tasmania. The 28 hunters killed a total of 128 deer (33 males, 87 females and 8 unknown) during 306 hunts. The annual harvest comprised 21%–26% of the total deer population (28%–38% of the female population). During the four-week ‘buck’ season (March), hunters exhibited more selective hunting behaviour characterised by frequent hunts that targeted mostly antlered males with low catch per unit effort (0.03 deer killed per hour). In contrast, the 8-month antlerless season (March–November) was characterised by a more opportunistic hunting behaviour with fewer hunts and a higher catch per unit effort (0.11 deer killed per hour). Our results show that the current regime of recreational hunting is not reducing the population. If landowners decide to rely on recreational hunting to reduce deer densities on their properties, more deer, especially females, need to be harvested annually. Changes to regulations that increase the number of deer harvested should be considered in parallel with greater incentives for recreational hunters to harvest more females. Other deer control methods, such as helicopter-based shooting and professional ground-based shooting, are likely to provide faster and greater reductions in the densities of non-native deer populations than recreational hunting while non-lethal management should be considered for local asset protection.
Rob BrewsterFrancesca RoncolatoTom JamesonBruno Oliveira Ferronato...
e12623.1-e12623.12页
查看更多>>摘要：In Australia, conservation fences are widely used to enclose threatened native species in an area while excluding European Red Foxes (Vulpes vulpes) and Cats (Felis catus) that threaten them. However, conservation fences can have unintended negative consequences on other species within their vicinity, interrupting movement patterns and causing mortality via entrapment. A key component of conservation fence design should be the inclusion of structures to allow the transit of species negatively affected by fences, while maintaining an effective barrier to threats. In this study, we designed and tested a method to allow the movement of Eastern Long-necked Turtles (Chelodina longicollis) through a ‘turtle tunnel’ under a conservation fence. This Australian freshwater turtle periodically migrates over land in response to changing weather conditions, wet-dry cycles of wetlands, to nest, and to seek habitat and food resources. We tested the ability of wild-caught Eastern Long-necked Turtles to enter and traverse turtle tunnels in pen trials. We found that Turtles were able to navigate the turtle tunnels as intended, with 100% of individuals entering tunnels and 44% successfully traversing the tunnels during the timed trial. These results were used to inform the placement of nine turtle tunnels along a new conservation fence at Booderee National Park, Jervis Bay Territory, Australia. We monitored installed turtle tunnels at Jervis Bay for 6 months using a combination of camera traps and observational data collected during daily fence line checks. We found further evidence for the use of tunnels by Eastern Long-necked Turtles and found that Foxes did not attempt to traverse tunnels. From our findings, we suggest that turtle tunnels be considered in the construction of conservation fences where they intersect with known areas of freshwater turtle migrations, but that further research is required to assess the long-term effectiveness of the design as a wildlife transit device.
Samuel HislopMariela Soto-BerelovSacha JellinekYung En Chee...
e12624.1-e12624.11页
查看更多>>摘要：Riparian vegetation is important for biodiversity, creates habitat for various fauna and provides vital ecosystem services such as flow regulation, water filtration, uptake, transformation and cycling of minerals, nutrients and organic matter. These ecological functions and processes contribute to the health of waterways. In many urban and semiurban areas, riparian vegetation is subject to degradation pressures such as land clearing for urban development, altered hydrological regimes due to modified catchment land cover and runoff patterns and other human-induced disturbances. Monitoring riparian vegetation cover and condition is vital for informing effective management. This can be achieved via detailed field assessment; however, this is often costly, time and labour intensive and extremely difficult to undertake across large regions such as an entire stream network. This study examines the utility of medium-resolution Sentinel-2 satellite imagery for monitoring riparian vegetation across the Greater Melbourne region, Australia. The paper demonstrates several examples of how spectral trends from Sentinel-2 imagery (2019–2023) can be used to provide insights, which are expected to improve over time as more data become available. We also assessed the potential of combining Sentinel-2 imagery with field observations to model riparian vegetation conditions. Using 425 field observations and a series of Sentinel-2– derived predictor variables, a Random Forest regression model was developed to model riparian vegetation condition. The model explained 53% of the variance in the data. Although the spatial resolution of Sentinel-2 (10 m) is a limitation when working with narrow riparian vegetation corridors, our methods demonstrate it can be used to help prioritise areas for protection and/or enhancement and identify areas that may be at risk of further degradation. This can assist waterway managers to prioritise field activities such as restoration and revegetation, and the control of key weeds and browsing animals.
查看更多>>摘要：Direct seeding is a technique frequently used to restore degraded lands worldwide. Direct seeding is attractive to restore degraded lands mainly because of its low cost compared to planting seedlings. However, this technique has been poorly studied in tropical mountains. Here, we investigated the outcomes of direct seeding at four degraded sites in the Andean mountains of Cauca, Colombia. We used 45 native tree species, most of them commonly used in restoration projects in the Andean region of Colombia. After 150 days of sowing, we evaluated seedling emergence, survival and establishment costs. Performance of direct seeding was markedly different across sites. Most species had low seedling emergence, with Guayaba (Psidium guajava) and Matachande (Bocconia frutescens) showing the highest emergence. Species with large seeds showed higher emergence compared with medium and small seeds. Seedling density was considerably variable among sites, ranging from 496 to 5550 ind. ha−1. Our results evidence the need for long-term monitoring at mountain restoration sites and that restoring tropical degraded mountains using direct seeding is a challenge that can be complemented with native tree planting. Further research is required to explore the advantages and disadvantages of direct seeding in mountain terrain.
查看更多>>摘要：Kangaroo grass (Themeda triandra Forssk.) is a widespread summer-active native tussock grass that has been removed from many ecosystems through overgrazing, absence of fire or changes in land use. This review of kangaroo grass establishment trials in temperate Australia shows that it can be established from seed, but success varies depending on season, preparation of the area to be sown, sowing rates and methods, and especially on controlling competition from other plants until the kangaroo grass is large enough to suppress them. Controlling exotic plants before sowing kangaroo grass using physical, ecological or chemical methods has been effective but is often not enough to allow the kangaroo grass to establish well. Exotic plants emerging from the soil seed or bud bank after kangaroo grass emerges, have led to project failures or prevented kangaroo grass from thriving. Research will help us learn how to control exotic competitors, especially which methods to use and when. Furthermore, most methods of establishing kangaroo grass have been suited to small areas of up to several hectares, and broadacre methods need research and development. Given that seed is typically expensive or in short supply, efficient use of seed is essential; better ways to label, clean and sow the seeds of kangaroo grass are needed. The provenance of kangaroo grass seed is also important when used for ecological restoration as, broadly, plants with two chromosome sets (i.e., diploid) are better adapted to cooler/wetter regions and plants with four chromosome sets (i.e., tetraploid) are more suited to hotter/drier areas.
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