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Harnessing Biodiversity to Improve Vineyard Sustainability A.M. Barnesa and S.D. Wratten H.S. Sandhu

Bio-Protection Research Centre CSIRO Sustainable Ecosystems P.O. Box 84 PMB No 2 Lincoln University Glen Osmond Lincoln 7647 SA5064 New Zealand Australia Keywords: agroecology, biological control, ecosystem services, educational initiatives,

Greening Waipara, grower participation Abstract

Modern agricultural practices are becoming increasingly intensive and the expansion of farmland to help feed the burgeoning world population results in the destruction of natural ecosystems. Undisturbed natural areas contain significant amounts of biodiversity; this provides valuable ecosystem functions that are often overlooked in terms of the economic contributions they make to agriculture and our everyday lives. Viticulture, a large and expanding part of the New Zealand horticultural sector is used here as an example of how nature and profitable agriculture can co-exist. In this work, biodiversity is being enhanced under and between vine rows and outside the vine blocks, including biodiversity trails. Vineyards are monocultures, severely reducing ecosystem services with a consequent increasing need for “substitution agriculture” i.e., oil-based inputs such as pesticides, fungicides and insecticides, incurring high variable costs. The Greening Waipara project and its associated protocols were developed partly in response to market pressures from an increasingly environmentally discriminating northern hemisphere wine market. Agriculture and conservation are often viewed as being incompatible, but by introducing functional agricultural biodiversity (FAB) into the vineyard environment, ecosystem services are substituted for unsustainable oil-based inputs. Additional benefits for winegrowers include eco-tourism and marketing opportunities through product differentiation. INTRODUCTION The Value of Ecosystem Services

Ecosystems provide a multitude of functions that benefit humankind. When monetary values are assigned to these ecosystem functions they are known as ecosystem services (ES), otherwise known as nature’s services. Valuable ES include pollination, soil formation, flood mitigation, carbon capture, biological control, tourism and aesthetics. Ecosystem Services can be further categorised in regards to their function (Fig. 1).

In 1997, Costanza et al. (1997) attempted to assign a dollar value to the ES provided by the entire biosphere. The global value of ES was estimated at US$33 trillion/year, but this is regarded as a minimum estimate due to the lack of data available at the time of writing. Their estimate of ES provision on farmland was particularly low, at US$92/ha. Relationship between Biodiversity and ES

Biodiversity produces ES, but we are currently experiencing unprecedented rates of global biodiversity loss. The exact current rates of extinction are uncertain but estimates put them between two and three orders of magnitude higher than rates found in the fossil record (Cardinale et al., 2006). For example, the Canterbury Plains on the East Coast of the South Island of New Zealand have less than 1% of the indigenous vegetation a Anna-Marie.Barnes@lincoln.ac.nz

Proc. Organic Fruit Conference Eds.: R.K. Prange and S.D. Bishop Acta Hort. 873, ISHS 2010

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cover remaining (Walker et al., 2006). Agriculture is the main cause of biodiversity loss: the use of land to yield goods

and services represents the most substantial human alteration of the earth system (Vitousek et al., 1997). Agriculturalists are the chief managers of useable land, that is, land that is not classified as desert, tundra, rock or boreal. Approximately half of global useable land is already under pastoral or intensive agriculture (Tilman et al., 2002). Modern farming systems usually consist of large-scale monocultures with correspondingly low provision of ES.

An example of a vital ES currently in decline worldwide is that provided by pollinating insects, particularly bees. Colony Collapse Disorder (CCD) is decimating hives in the United States of America; the varroa bee mite (Varroa destructor), an aggressive parasite which affects bee populations in both managed and feral hives is now present throughout New Zealand and apple producers in China have resorted to pollinating their trees by hand due to reduced pollinator populations (Partap et al., 2001). Agriculture, Biodiversity Loss and World Population Growth

The burgeoning world population is estimated to reach 9 billion by 2050 (UN Department of Economic and Social Affairs, 1999) and the main challenge currently facing society is that of feeding the world’s rapidly increasing population in a sustainable manner. Future methods for meeting the demand for food by a larger, wealthier global population must meet the needs of the environment as well as the global market. Ecosystem Services provision must improve and productivity levels should be maintained or increased wherever possible. It is preferable that any increase in production is accomplished without a corresponding increase in the area of land under agricultural production if we wish to ‘save land for nature’. Most of the best quality land is already used for agriculture, so any further expansion would spill into marginal land that is already incapable of sustaining high yields, degrading the value of this land further (Tilman et al., 2002).

Biodiversity loss and reduced ecological resistance in engineered landscapes is unfortunately commonplace, with the detrimental environmental impacts of agricultural practices going largely unmeasured and having little influence on farmer or societal choices regarding production methods (Tilman et al., 2002). The ‘external costs’ associated with chemical-dependent intensive agriculture include damage to soil fertility, water quality and human health, as well as often-irreparable damage to biodiversity (Sandhu et al., 2007). The two main processes that result in biodiversity loss are reductions in the size of natural areas and changes in ecosystem conditions (Martens et al., 2003). Global climatic change is providing further challenges for agriculture as species distributions change and extinction rates increase.

The consequences of biodiversity loss and consequent loss of ES such as biological control can be difficult to detect. One method of measuring the decline in biological control by non-tradable beneficial species on farmland is the use of sentinel baits. Figure 2 shows the difference in insect predation rates in organic and conventional arable fields, detected using this experimental method.

Background biological control of only one pest guild by one natural enemy guild on organic farms can reduce variable costs by up to NZ$130/ha/yr and is a significant source of pest suppression in a system largely dependent on ES to keep pest populations low – most chemical inputs are prohibited in organic agriculture (Sandhu et al., 2007). Conventional agriculture requires significant quantities of synthetic oil-based fertilisers, which add globally-significant amounts of environmentally detrimental nitrogen and phosphorus to terrestrial ecosystems (Tilman et al., 2002). METHODS

Detailed methods are not given here but can be found in Berndt et al. (2006), Scarratt et al. (2008) and Jacometti et al. (2007a, b).

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RESULTS AND DISCUSSION Improving Resistance and Resilience to Pests in Agro-Ecosystems

The acronym SNAP summarises a practical (biological control based) conservation approach to improving ES on farmland. Biodiversity is boosted by providing the following food and habitat sources for beneficial species: Shelter, Nectar, Alternative prey, Pollen. Careful consideration must be given when introducing new species to provide SNAP into an ecosystem – how much biodiversity should be introduced, what type and where should it be deployed? A common perception is that as species richness increases, there is a continual proportional increase in ecosystem function (complementarity between species). This is not usually the case, however, with a steady increase in ecosystem functioning followed by an eventual levelling out being more common (‘redundancy’ between species). It is also possible that an introduced species will have a negative impact on the ecosystem, resulting in a sharp decline in ecosystem function after increasing initially; therefore any plant or animal species deliberately introduced to an ecosystem must be thoroughly investigated in regards to its suitability before release (Fig. 3). A relevant example is the case of the harlequin ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) which now has the unenviable status of “the most invasive ladybird on Earth” (Roy et al., 2006; www.harlequin-survey.org). Native to Asia, H. axyridis was initially sold in Europe and North America as a commercial biological control agent of aphids and coccids (Brown et al., 2007). Although H. axyridis has been effective in controlling a range of pest insects in a variety of crops, it is now classified as an invasive alien species. A voracious polyphagous predator, out of its native range H. axyridis displaces native aphidophagous species through direct competition (Majerus et al., 2006) with biodiversity declines as a result. Present in the United Kingdom since 2004 and with populations increasing rapidly, a national survey website (www.harlequin-survey.org) has been launched to monitor its spread and the possible impacts on native ladybird species.

Research at the Bio-Protection Research Centre, Lincoln University, has centred around planting the introduced annual species tansy leaf (Phacelia tanacetifolia), buckwheat (Fagopyrum esculentum) and selected endemic New Zealand trees and shrubs in and around vineyards and pastoral farms to augment the biodiversity in productive agricultural ecosystems, with a net result of significantly increasing the variety, quantity and quality of ES provided, including biological control of pests and diseases.

The lightbrown apple moth Epiphyas postvittana Walker (Lepidoptera: Tortricidae) (LBAM) is a significant pest of grapevines in New Zealand and Australia and has recently invaded California. The larvae (leafrollers) damage grape bunches by feeding on berries, flowers and stalks. This causes a direct reduction in yield, but more importantly the larvae promote the spread of the fungal disease grey mould, Botrytis cinerea, increasing the incidence of infected bunches and the severity of infection within bunches (Lo and Walker, 2006). The presence of B. cinerea can reduce grape yield, taint wine and increase its sensitivity to oxidation (Mullins et al., 1992).

Dolichogenidea tasmanica is a hymenopteran larval parasitoid of LBAM and is the most abundant of the 22 parasitoids found in New Zealand that attack LBAM. Prior to the introduction of the New Zealand Integrated Winegrape Production scheme in 1998, vineyard leafroller control was limited in many cases to calendar-based spraying of broad-spectrum insecticides (Berndt et al., 2006).

Introducing floral resources to agricultural ecosystems provides beneficial insects such as parasitic wasps and hoverflies with a reliable source of nectar (a carbohydrate energy source) and pollen (which provides protein, necessary for egg production), hence increasing their longevity and fecundity. Flowering plants also provide a protective physical habitat for invertebrates, a feature of which many conventional agricultural landscapes are severely lacking.

Sowing one inter-row in ten with buckwheat can help vineyard owners to avoid pesticide use against leafrollers by enhancing populations of D. tasmanica. As shown in

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Figure 4, these wasps can help bring the number of LBAM larvae present in grape bunches below the economic spray threshold.

Mulching these non-native plants after their nectar has delivered biological control enhancement may accelerate degradation of vine prunings, interrupting the life cycle of B. cinerea. Recent research has shown that mulching the under-vine area with plant material from cover crops, grape marc or with shredded office paper reduces grape infection rates to such an extent that fungicides are no longer needed (Fig. 5). The increased soil moisture provided by these mulches raises functional soil biological activity, resulting in increased vine debris degradation, reduced B. cinerea primary inoculum on the debris and decreased B. cinerea at flowering and at harvest (Jacometti et al., 2007a).

These two simple strategies allow pests and diseases to be brought below their economic thresholds naturally, saving up to NZ$1000/ha/year in New Zealand vines through ‘ecological engineering’ of what were formerly high input vineyards. The ‘Greening Waipara’ Project

Often the best way of generating interest and promoting uptake of a new method or technology is to create a practical working example of the model system at hand and incorporate elements of ‘social learning’ (Cullen et al., 2008; Warner, 2007). The Greening Waipara project, located in the Waipara Valley, North Canterbury, New Zealand is a prime example of the promotion of a sustainable approach to managing an area of productive land which could otherwise become a bleak monocultural landscape. Functional agricultural biodiversity (FAB) is being introduced to vineyards and farms in the form of native New Zealand plants, as well as introduced species such as buckwheat and phacelia.

Educational initiatives stemming from Greening Waipara operate at many levels in the Waipara-North Canterbury community, further afield in the greater Canterbury region as well as in a national context. The project began in 2005 with native plantings in four vineyards in the valley. In July 2009, the number of properties involved was 51, including plantings on pastoral farms, a variety of horticultural operations (including but not limited to vineyards) and the local primary school. There are a further seven plantings at prominent sites throughout the community such as the local domain and road frontages on State Highway One; local community groups and families are extremely supportive of the project with a correspondingly high level of participation on planting days as well as funding being sourced elsewhere.

Research is being carried out into the specific ES that endemic New Zealand plant species are capable of providing. Of key interest are two characteristics with the potential to decrease vineyard pesticide inputs: the sugar ratios of the nectar of native plants and their contribution towards enhancing the longevity and fecundity of beneficial insects (Vattala et al., 2006) and the ability of endemic groundcover plants to suppress weeds in the under-vine area. Vineyard Biodiversity Trails

Four participating vineyards with adjacent restaurants or tasting rooms have opened ‘biodiversity trails’. These are a world-first for vineyards and a further step in educating children and families who visit Waipara vineyards about the cultural and ecological values of native plants and their contribution to the provision of ES.

Educational quizzes have been developed for children, unique to each trail, with prizes including a puzzle book and the chance to win a Maori hand-woven flax basket (kete) containing NZ native plant seeds – an excellent way for children to reinforce their in-vineyard experience of the value of biodiversity.

In early winter 2008, several researchers involved with Greening Waipara toured the main winegrowing regions of New Zealand at the invitation of Sustainable Winegrowing New Zealand (http://www.nzwine.com/swnz/) and presented a series of interactive workshops. These were well received by the people who are of paramount importance in the process of implementing and expanding sustainable management

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programs – the winegrowers themselves. There are plans to extend the programme to the other major winegrowing regions of NZ.

The benefits to growers joining a programme such as Greening Waipara are many – increased sustainability and profitability due to increases in ES provision and the related decrease in pesticide use and increased marketability due to product differentiation – Greening Waipara-specific back labels are now in use. The project also helps the relatively new Waipara Valley wine region distinguish itself from the other more established New Zealand wine regions by projecting a dynamic, sustainable image from a unique vantage point; overseas marketing opportunities are likely to be enhanced as a result.

The project has a strong media profile and continues to attract national and international attention. More information about the project can be found at http://ecovalue.uvm.edu/newzealand and http://www.bioprotection.org.nz/greening-waipara.

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Cardinale, B.J., Srivastava, D.S., Duffy, J.E., Wright, J.P., Downing, A.L., Sankaran, M. and Jouseau, C. 2006. Effects of biodiversity on the functioning of trophic groups and ecosystems. Nature 443:989–992.

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Cullen, R. 2007. Ecosystem services and native plants and communities on the Canterbury Plains. In: The role of native plants and native plant communities on the Canterbury Plains and their contribution to sustainable development. In: Proceedings of the Flock Hill Workshop held at Lincoln University, 26–27 April 2007.

Cullen, R., Warner, K.D., Jonsson, M. and Wratten, S.D. 2008. Economics and adoption of conservation biological control. Biological Control 45:272–280.

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Jacometti, M.A., Wratten, S.D. and Walter, M. 2007b. Understorey management increases grape quality, yield and resistance to Botrytis cinerea. Agriculture, Ecosystems and Environment 122:349–356.

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Majerus, M., Strawson, V. and Roy, H. 2006. The potential impacts of the arrival of the harlequin ladybird, Harmonia axyridis (Pallas) (Coleptera: Coccinellidae), in Britain. Ecological Entomology 32:207–215.

Mullins, M.G., Bouquet, A. and Williams, L.E. 1992. Biology of the grapevine. Cambridge University Press, Cambridge, New York.

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and farmers’ management strategies in Hengduan Mountains, China. Acta Hort. 561:225–230.

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Figures

Fig. 1. Range of ecosystem services provided by the biosphere (adapted from Cullen,

2007).

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Fig. 2. Mean rate of predation (percent removal/24 h) of aphids and fly eggs in selected

fields (H.S. Sandhu, S.D. Wratten and R. Cullen, Ecological Complexity – in review).

Fig. 3. Relationships between ecosystem function and biodiversity (M.B. Thomas and

S.D. Wratten, unpublished).

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Fig. 4. Proportion of grape bunches infested light brown apple moth Epiphyas postvittana

Walker (Lepidoptera: Tortricidae) larvae when buckwheat is or is not deployed in the vineyard. Economic threshold for leafrollers shown (S. Scarratt, unpublished data).

Fig. 5. The effects of different under-vine mulch treatments on B. cinerea infection rates

of grape bunches at harvest in New Zealand (modified from Jacometti et al., 2007b).