2017, Peisley, Rebecca K, Saunders, Manu, Robinson, Wayne A, Luck, Gary W

Scavenging birds can provide ecosystem services to pastoralists by contributing to the breakdown of animal carcasses that can harbour and spread disease. However, these benefits have yet to be quantified in Australia. We monitored rabbit carcasses using motion-sensor cameras to identify beneficial avian scavengers across four landscape types (forest, riparian, fields with large isolated trees, and open fields) on a pastoral property in north-central Victoria. We quantified the ecosystem service of carcass breakdown by measuring the per cent weight loss of carcasses exposed to scavenging birds compared to carcasses excluded from birds. Seven of the twenty-four bird-accessible carcasses were attacked by raptors in 2014, and three in 2015. When a raptor attacked a carcass, there was a significantly higher median per cent weight loss of the carcass (16.67%, interquartile range (IQR) = 8.33-100.0) compared with sites where no bird attacks occurred (6.65%, IQR = 3.03-12.06). Our results indicate that raptors are major contributors to carcass breakdown in grazing landscapes and may potentially contribute to reducing the spread of diseases such as blowfly strike and leptospirosis. Maintaining key habitat features for these species (e.g. large isolated trees) is essential for raptor conservation and maximising the ecosystem services they provide.

2014, Luck, Gary W, Spooner, Peter G, Watson, David M, Watson, Simon J, Saunders, Manu

Five years of research on interrelationships between fauna use of almond plantations and native vegetation in north-western Victoria shows that almond plantations have a strong influence on fauna dynamics and in some cases may provide important habitat for threatened species.

2015, Saunders, Manu, Luck, Gary W, Gurr, Geoff M

1 Homogeneous tree crop plantations can adversely impact wild pollinator communities by limiting the temporal continuity of food and the availability of nesting sites. Identifying how structural differences between plantations and natural vegetation influence pollinator communities is necessary for ecological management of agroecosystems. 2 Communities of potential wild pollinators (native bees, wasps, flies) were compared between monoculture almond plantations and native vegetation in a semi-arid region of southern Australia, before, during and after the late winter almond flowering period. Abundance and richness of each insect group were related to site heterogeneity and keystone structural resources at each site, focusing on food and nesting resources. 3 Relationships with site heterogeneity varied between taxa and across months. Native bee abundance and richness were strongly associated with specific keystone resources, despite showing no association with site heterogeneity. 4 The present study highlights the value of focusing on biologically meaningful resources when investigating relationships between insects and habitat, rather than on generalized heterogeneity metrics. The results suggest that maintaining keystone resources in agroecosystems can support the conservation of insects and ecosystem services, especially in areas where homogeneous agricultural systems overlap dynamic natural ecosystems.

2016, Saunders, Manu

Homogenization of agricultural landscapes affects ecological processes and biodiversity and can affect the community composition of ecosystem service providers. These effects can have particular impact in landscapes dominated by monocultures of pollinator-dependent tree crop plantations, which create both spatial and temporal homogeneity at the landscape scale. I looked for associations between the proportion of nearby unmanaged vegetation and potential wild pollinator groups collected within flowering almond orchards in two types of landscape. In the Complex landscape, characterized by a heterogeneous mosaic of multiple crops, semi-natural grassland and natural woodland, insect pollinator groups were not associated with unmanaged vegetation. In the Simple landscape, dominated by monoculture almond plantations, most pollinator groups showed positive relationships with the two unmanaged vegetation types (grassland and woodland). In particular, all wild bee and all but one hoverfly individual were found in remnant native vegetation patches within almond plantations, rather than within rows of almond trees. More research is necessary to identify how structural differences created in monoculture landscapes, between crops and the native vegetation they encroach on, influence ecological communities and the provision of ecosystem services.

2014, Saunders, Manu, Luck, Gary W

Agricultural landscape elements, such as field edges, are not always a barrier to insects but can influence their distribution and dispersal behaviour. The present study investigated spatial and temporal patterns in wild pollinator (fly, wasp and non-Apis bee) distribution across an edge between natural mallee woodland and monoculture almond plantations in southern Australia, during the critical almond flowering period. This is the first study of variation in pollinator community distribution on both sides of an edge between natural vegetation and flowering tree crop plantations. Species richness, diversity and evenness (SHE) analysis was also used to identify changes in pollinator community structure relative to the edge. It is shown that the spatial distribution and structure of pollinator communities can vary across a habitat edge with an abrupt temporal changes in resources. Our results suggest that the plantation edge did not prevent wild pollinators spilling over from woodlands, although vegetation homogeneity and phenological changes in resources most likely influenced the dispersal of pollinators into plantation interiors. The findings of the present study contribute to our knowledge of edge responses by insects in managed landscapes and could motivate growers to adopt ecological management practices in commercial plantations. Future studies of insects near farmland edges should include samples on both sides of the edge and should also consider the landscape context.