Wildlife in production landscapes
Agriculture has been important in the development of Aotearoa/New Zealand’s contemporary environment, economy, and society and continues to play a significant role, with production lands currently covering 58% of New Zealand’s total land area and agricultural-based products making up about 53% of its merchandise exports. Although significant changes have occurred in agricultural land use and management practices in recent decades, the impacts of these on biodiversity and the wider agro-ecosystem are largely unknown. Consequently, concerns have been raised about the need for schemes to monitor reliable indicators of sustainable land use, both nationally and regionally. Without information on the environmental status and trajectory of New Zealand’s agro-ecosystems, it is not possible to know where we are in terms of sustainable agricultural practice, where we are trying to go, or if we have any chance of getting there. Our research programme aims, therefore, to inform sustainable land management and biodiversity conservation strategies in New Zealand’s agricultural landscape through better understanding of the status and ecology of wildlife populations, primarily birds, in farmland areas.
Birds as crop pests
Bird damage to crops is one of the biggest problems facing growers of a wide variety of arable and horticultural crops in New Zealand. To try and minimise such damage, farmers may use bird control techniques such as scarers, shooting, chemical repellents or poisons. Yet, these techniques are often economically or environmentally unsustainable or simply ineffective. Development of more effective bird pest management strategies has been hampered by a lack of understanding of patterns of bird damage and the ecology of pest species. Working in collaboration with the Foundation for Arable Research, our research aims to fill these knowledge gaps by investigating:
- Growers’ perceptions of bird damage, control and management in arable crops to identify the key research and management issues that need to be addressed.
- Spatial and temporal patterns in crop damage as well as bird pest abundance, composition and distribution on arable farms.
- Bird pest population dynamics and movement patterns in the agricultural landscape.
Disease vectors
Land-use changes are key drivers of disease emergence globally, most often through their influence on the distribution and abundance of animals that act as vectors or reservoirs of disease. In collaboration with the Institute for Environmental Science and Research, we are thus interested in the influence that the modified agricultural landscape in New Zealand has on:
- Invertebrate vectors of disease, such as mosquitoes, flies and ticks, that globally vector a wide variety of diseases of concern to agriculture, wildlife and public health, including bluetongue, Ross River virus, avian malaria and dengue fever
- Pest bird flocks, which can both disseminate bacterial infections that contaminate the agricultural food chain (such as Salmonella and Campylobacter) between farms and act as reservoirs of vector-borne diseases (such as West Nile virus in the United States)
- Pest mammal reservoirs of infection, such as possums for Tb, and rats and mice for infections of concern to public health such as leptospirosis, bubonic plague (reported in New Zealand in the past) and murine typhus (for which the number of reported cases has recently increased)
Indicators of sustainable land use
The bellbird is one of New Zealand’s iconic bird species, but would it be a suitable indicator for monitoring sustainable land management in the agricultural landscape? (Photograph: C MacLeod)
The lack of farmland biodiversity information is a notable gap in New Zealand’s current capacity for assessing sustainability of land use. With key markets for New Zealand agricultural products becoming more concerned with the sustainability of production (e.g. UK supermarket chains), the provision of indices based on such information are likely to become essential for maintaining market access. In Europe and North America, the negative impacts of agricultural intensification on bird populations are well documented and, therefore, birds have been identified as suitable indicators of sustainable land use. However, in New Zealand, very little is known about the status or composition of its farmland bird populations or the main factors limiting their populations.
We are currently working in collaboration with the Agricultural Research Group on Sustainability (Otago University) to investigate the importance of habitat composition and land management practices in determining the composition of bird communities in New Zealand’s agricultural landscape. We are also interested in understanding the potential conflicts between bird pest and conservation management strategies in New Zealand’s wider landscape.
Invasion ecology
Working in collaboration with the British Trust for Ornithology and Lincoln University, we use New Zealand’s introduced birds and their parasites as models for testing theoretical questions relating to invasion and evolutionary ecology, for example:
- mechanisms determining the enhanced success of introduction bird species
- mechanisms and processes determining the successful introduction of parasite species on introduced hosts