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Reduce Pests and Diseases

The reduction of pests and diseases, vectors and pathogens. This includes the reduction of crop damage by herbivory (e.g. insects) and reducing the risk of disease to animals and humans.

 

Millennium Ecosystem Assessment Service Category

Regulating Services

 

What is reduce pests and disease and how is it derived?

An icon of natural pest control is the ladybird beetle. Benefits of which have been known since the 1600s.

Ross River Fever is a mosquitoe-borne infection disease causing flu-like illness in humans.

Buffalo flies are rated one of the most economically important animal health issues affecting the profitability of beef and dairy operations in Queensland.

Throughout time insects and pathogens have competed with humans for food and resources. Currently, more than 40% of world food production is being lost to insect pests, pathogens and weeds, despite the application of 3 billion kilograms of pesticides to crops. Arthropod pests and plant pathogens destroy an estimated 15% and 13% of food crops, respectively. Larger exotic pests (e.g. rabbits, rats, feral pigs, cane toads and foxes) have also played a significant role in competing for food with native species as well that produced for humans. Many species (e.g. flies, worms and mosquitoes) can carry disease having significant consequences for human health. Capturing natural pest control, sometimes referred to as conservation biological control, offers many opportunities to increase food security, environmental sustainability and the physical health of humans.

Table 1 below presents the magnitude different ecosystem functions contribute to reducing pests and disease (relative to other ecosystem functions). It is now recognised that supporting habitats such as native remnant vegetation and regrowth areas are extremely important for supporting the natural enemies that contribute to reducing pests and diseases (little information is known about important areas for this service in aquatic and marine environments). Native remnant vegetation can provide nesting sites for natural enemies, food in the form of alternative prey and nectar and refuge from insecticides. Genetic variation allows species to adapt to changing biotic (living) and climatic conditions, and it is the backbone of biological diversity. Having a diverse array of natural enemies can result in better pest suppression because different species feed on pests in different ways (e.g. some attack leaf feeders, others attack stem borers) and provide ‘insurance’ when some species are only periodically abundant. 

Climate and water regulation have significant effects on species abundance, composition and range or distribution in a geographical region; hence species interactions. Climate variability = ecosystem complexity = biological diversity. Disruption to the natural dry-season ecology of mosquitoes in tropical climates, through continual irrigation of crops or unseasonal river flows from storage dams, can upset the natural climatic controls over species population numbers and lead to increased outbreaks of mosquito borne disease (i.e. Ross River Virus and Dengue Fever).

Waste treatment and assimilation by invertebrates, chemical recomposition, assimilation and distribution can result in improved nutrient cycling and soil structure, reduced pests (e.g. flies) and diseases (e.g. buffalo flies which parasitise cattle and bush flies which vector both human such as eye trachoma and animal diseases). Native vegetation in catchment areas act as a biological filtering agent of water runoff destined for human use. Clearing of native vegetation can lead to contamination of water sources and outbreaks of enteric illness such as campylobacteriosis, giardiasis and cryptosporidiosis. Landscape opportunity contributes to reduced pests and diseases through science education opportunities and overall context of food production. For example, an icon of natural pest control is the ladybird beetle. This had tremendous cultural significance dating back to the 1600s in European agriculture.

 

Table 1:The relative magnitude (to other ecosystem functions) each ecosystem function contributes to Reducing Pests and Diseases.

Ecosystem Function Category Ecosystem Function 0
1
2
3
4
5
Regulating Functions
Gas Regulation





Climate Regulation





Disturbance Regulation





Water Regulation





Soil Retention





Nutrient Regulation





Waste Treatment and Assimilation





Pollination





Biological Control





Barrier Effect of Vegetation





Supporting Functions
Supporting Habitats





Soil Formation





Provisioning Functions
Food





Raw Materials





Water Supply





Genetic Resources





Provision of Shade and Shelter





Pharmacological Resources





Cultural Functions
Landscape Opportunity





 

Are human inputs required to facilitate the reduction of pests and disease?

Pot plant bases, pools, buckets, bird baths and ponds can provide breeding areas for pests such as mosquitoes.

A combination of human controls (fencing) and natural controls (native vegetation) can reduce predation of crops by large and small pests.

Landscape context and design, both composition and arrangement, will significantly impact on the provision of this service.

This ecosystem service is delivered freely (mostly) by natural ecosystems. The elimination or reduction of broad spectrum insecticides however that kill natural enemies of pests will benefit the capture of pest control services. In addition, on farms that are highly degraded and lacking in natural habitat the rehabilitation and revegetation along fence rows, stream banks or paddocks has potential to aid the capture of pest control services. In addition, commercial insectaries (such as Bugs for Bugs, Mundubbera QLD) produce a wide array on natural enemies (native and exotic) for the control of native and exotic pests in a wide range of crops. This has been most successful in citrus. The opportunity for innundative release of natural enemies reduces insecticide input into the environment and increases the opportunity for natural enemies of other crop pests to do their job. There are also a number of other tools and techniques that may be applied to reduce larger pests such as fencing, baiting and trapping but these are expensive.

Altering land use practices can increase the risk of disease burden to humans by direct or indirect means. For example, the clearing of native vegetation can reduce ecosystem complexity - allowing for competitively advantageous rodent species to thrive and spread disease risk to humans (e.g. hantaviral disease, leptospirosis and more historically - the plague); and the contamination of waterways and meat produced from farming stock has long been associated with communicable zoonotoic diseases (e.g. enteric diseases, Q Fever, Salmonella, cryptosporidium and giardia). To date, the use of vaccines and pesticides as treatment or prevention of many diseases are fire fighting tools to restore balance. While humans continue to develop technological and cultural buffers against environmental change, ultimately, we are reliant on proper ecosystem functioning for continued well-being and survival. Human activities that can facilitate or restore this service might include: the revegetation of catchment areas therefore restoring ecosystem functions; the reduction of artificial habitat for vectors of water borne disease (e.g. buckets of water that mosquitoes can breed in); the decrease of greenhouse gas emissions to maintain climate regulation; and any other activity that supports ecosystem health therefore reducing potential for indirect human health consequences.

 

Are there any barriers to people receiving this ecosystem service and its benefits?

There are many projects making the link between the private benefits of pest control and the public benefits of conservation. Landscape context and design, both composition and arrangement, will significantly impact on the provision of this service. There is increasing recognition that agricultural pest control must be considered beyond the scale of the field. Insect pests and diseases are often highly mobile and quickly invade fields from the surrounding landscape. Therefore, the amount and arrangement of non-crop habitat (e.g. native remnant vegetation) supporting natural enemies or wind breaks that change the flow of disease spores can contribute to a more pest suppressive landscape.

One of the greatest barriers preventing people from accessing this service is the comprehensive science that clearly demonstrates the means of maintaining and capturing the service. Once a decision is made to protect this service, the barrier to effective delivery of pests and disease management is not so much a regulatory one but an economic or social one (i.e. prioritising ecosystems and human health against competing socio-political pressures). This ecosystem service provides many benefits that contribute both directly and indirectly to the well-being of the SEQ community. The Constituents of Well-being this ecosystem service contributes to are presented in Table 2 below. Further information on these constituents and how ecosystem services contribute to them can be obtained by clicking on the links in the table.

 

Table 2:The relative magnitude (to other ecosystem services) Reduce Pests and Diseases contributes to each constituent of well-being.

Well-being Category Constituent of Well-being 0
1
2
3
4
5
Existence
Breathing            
Drinking            
Nutrition            
Shelter            
Health
Physical Health            
Mental Health            
Security
Secure and Continuous Supply of Services            
Security of Person            
Security of Health            
Secure Access to Services            
Security of Property            
Good Social Relations
Family Cohesion            
Community and Social Cohesion            
Freedom of Choice and Action
Social and Economic Freedom            
Self Actualisation            

  

HOW DO WE KNOW IF WE ARE DEGRADING, MAINTAINING OR IMPROVING reduce pests and disease?

 

Reptiles such as snakes and lizards play an important role in controlling populations of insects, amphibians, birds, small mammals and other reptiles.

Links to other publications and websites

Bugs for Bugs - IPM
Qld Govt. - Mosquito Borne Disease
Melbourne Uni. - Mosquito Disease
Water Sanitation Health
AQIS Biosecurity

From an ecological perspective, the reduction of pest and disease is provided by maintaining ecosystem function and biodiversity and managing agricultural practices. Depending on the pest or disease and associated impacts there are a range of indicators that could be used to assess the provision of this service. To agriculture, the first indicator would be the presence of the pest control providers (e.g. natural enemies). The natural enemies that attack pests of crops are frequently known, but their requirements are not. The second indicator would be their persistence at different locations and over time. A more stable population of natural enemies (e.g. low variability) may provide more persistent pest control services. The third indicator is the demonstration of the successful capture of the pest control service, which is fewer pests and less insecticide used. For example, if remnant native vegetation on a farm is providing a source of natural enemies we would expect them to quickly colonise a field relative to the pest. This early colonisation would keep pest populations lower for longer, hence delaying insecticide sprays, reducing the number of sprays or other controlling efforts. 

Human disease outbreak data could readily be used as a bioindicator for regulating pest and disease from a human health perspective. In general, human populations are subject to more wide-spread surveillance, on both temporal and spatial scales, when compared to ecosystem health. As such, these data could be utilised to serve dual functions: 1) the detection and prevention of communicable human disease; and 2) establishing an early warning system of ecological disruption. Early detection of ecological disruption can also be used to further prevent future health implications for humans interacting with these environments. Such data surveillance tools would be well served by integrating the use of Human Health Information Systems with Environmental Health Information Systems.

 

How is this ecosystem service currently managed in SEQ?

There is no legislation for the sustainable use of this service. Also, there is no one organisation responsible for its management (although the Australian Quarantine and Inspection Service manages quarantine controls to minimise the risk of exotic pests and diseases entering the country). For more information on the reduction of pests and disease in agricultural production or for natural resource management contact CSIRO Entomology, Department of Agriculture, Fisheries and Forestry, SEQ Catchments or any of your agricutural organisations (e.g. the Biological Farmers Association, Growcom, Agforce or Horticulture Australia). From a human health perspective, ideally this service should be captured within Queensland government departments in place to manage/regulate land, water, climate and public health, such as the Department of Environment and Heritage Protection, the Department of Energy and Water Supply, the Department of Natural Resources and Mines and Queensland Health.