Ecosystem Services in Agricultural and Urban Landscapes

Stephen Wratten, Harpinder Sandhu, Ross Cullen, Robert Costanza, Stephen Wratten, Harpinder Sandhu, Ross Cullen, Robert Costanza

• Publisher: Wiley-Blackwell
• Year: 2013
• ISBN:
  9781118506240
• Edition: 1
• Topic: Sciences biologiques
• Subtopic: Zoologie

Ecosystem services are the resources and processes supplied by natural ecosystems which benefit humankind (for example, pollination of crops by insects, or water filtration by wetlands). They underpin life on earth, provide major inputs to many economic sectors and support our lifestyles. Agricultural and urban areas are by far the largest users of ecosystems and their services and (for the first time) this book explores the role that ecosystem services play in these managed environments. The book also explores methods of evaluating ecosystem services, and discusses how these services can be maintained and enhanced in our farmlands and cities. This book will be useful to students and researchers from a variety of fields, including applied ecology, environmental economics, agriculture and forestry, and also to local and regional planners and policy makers.

Part B

Ecosystem Services in Three Settings

4

Viticulture can be Modified to Provide Multiple Ecosystem Services

Sofia Orre-Gordon,^1,2 Marco Jacometti,² Jean Tompkins² and Steve Wratten²

¹ Barbara Hardy Institute, University of South Australia, Adelaide, Australia
² Bio-Protection Research Centre, Lincoln University, New Zealand

Abstract

In wine-producing regions, such as California and New Zealand, the wine industry has an increasing importance to national economies and growers have responded by increasing the area of land devoted to this crop. These virtual monocultures depend on high agrochemical input to control pest, disease and weed problems. This chapter covers different habitat modification methods that can be deployed to enhance existing naturally occurring ecosystem services within vineyards in an attempt to reduce the reliance on synthetic chemicals and increase the sustainability of the wine production.

Introduction

Little did the ancient Greeks know that one day the vine, grown for the wine that symbolized Dionysus, would occupy a vast bleak landscape, with bare soil or short mowed ryegrass on the ground between immeasurable rows of Vitis vinifera L. (Vitaceae), as is the case today.

Currently, around 2.7 million tonnes of wine is produced each year, primarily by Italy, France and the United States (FAO, 2011). Wine production in these and other wine-producing regions is rapidly expanding in area and volume, raising the importance of this crop to their respective national economies. In California, the fourth largest wine producer in the world, the wine industry has an annual impact of $US51.8 billion on the state’s economy and an impact of $US125.3 billion on the US economy as a whole. The industry creates 875 000 jobs throughout the USA and wine industry-related employment has increased by 37% since 2002, despite an increasingly competitive market environment (Wine Institute, 2006). Similar trends may be seen in New Zealand where wine production is one of the country’s top export earners. In the year 2008, the value of wine exports increased by 24% (Beef + Lamb New Zealand, 2010) making the wine industry worth close to $NZ1 billion for this South Pacific nation. Stimulated by this success, the area of wine grape production is rapidly rising with a 71% increase over the last 10 years, resulting in a total production area of 31 057 ha in 2009 (Aitken and Hawlett, 2010). Clearly, wine grapes are increasing in importance to national economies and growers have responded by increasing the area of land devoted to this crop.

This chapter covers different habitat modification methods that can be deployed to enhance existing, naturally occurring ecosystem services. Consequently, it will not cover inundative biological control methods, such as the application of ‘biofungicides’ and ‘biopesticides’ where pest control is achieved by the released biocontrol agents themselves and is often aimed at a shorter time period.

Rather it will look at how vineyards can be modified to enhance ecosystem services (see Chapter 1), especially that of conservation biological control (CBC) – a form of habitat manipulation to improve pest management. Enhancing CBC in vineyards has the potential to improve wine production sustainability as it can reduce the reliance growers have on external synthetic pesticide inputs.

Enhancing CBC in vineyards

Typically, vineyards are virtual monocultures which depend on high agrochemical input to control pest, disease and weed problems. This reliance on synthetic chemicals is high, partially because the simplified vineyard environment is inhospitable to natural enemies of pests, who consequently do not inhabit the vineyard in numbers sufficient to effectively control pest populations. Pesticides have come to replace natural enemies in the role of pest control. More recently, however, with the increased awareness of the need to find alternatives to pesticides, methods are being developed to bring back natural enemies to the vineyard and consequently reinstate a much-valued ecosystem service (Gurr et al., 2007).

A lot of work on habitat manipulations utilized to gain ecosystem function enhancement has been done within CBC (Jonsson et al., 2010). In CBC, habitat manipulation techniques are used to produce trophic cascades. These result in inverse patterns of abundance or biomass across more than one trophic level. In a three-trophic-level food chain, such as crop plants–herbivorous pests–natural enemies, enhancing the top predators (natural enemies) may result in lower abundance of mid-level consumers (herbivores pest) and a higher abundance of basal producers (crop plants) (Carpenter and Kitchell, 1993).

CBC utilizes these ‘top-down’ effects to increase the natural enemy population (Gurr et al., 2000). However, habitat manipulation can produce both ‘bottom-up’ and ‘top-down’ effects, consistent with the ‘resource concentration’ hypothesis and the ‘enemy’ hypothesis. According to both these hypotheses, herbivores are predicted to be more abundant in simple systems, that is monocultures, than in more complex ones (Root, 1973). According to the ‘resource concentration’ hypothesis, the reduction in herbivore abundance in complex habitats is caused by mechanisms such as dilution of the contrast between a concentrated crop and the soil. This produces a dilution of the visual and chemical stimuli for the herbivore, resulting in decreased colonization rates and increased emigration rates and thereby a reduction in damage to the crop (Gurr et al., 2000). As the herbivore population in the ‘resource concentration’ hypothesis is determined by a lower trophic level, the effects seen are ‘bottom-up’ effects. According to the ‘enemy’ hypothesis, predators and parasitoids are more numerous and/or effective in more diverse systems than in simple ones (Root, 1973). As the herbivore population in the ‘enemy’ hypothesis is impacted by a higher trophic level, the effects seen are ‘top-down’ effects. These effects are utilized in CBC, which specifically involves maximization of the impact of natural enemies by providing key ecological resources and by minimizing pesticide-induced mortality (Gurr et al., 2000) (Fig. 4.1).

Fig. 4.1 Conservation biological control shares common techniques with habitat manipulation but are not synonymous. (Data from Gurr et al., 2000).

In vineyards the main focus of habitat manipulation work has been on the control of leafrollers and Botrytis cinerea (Helotiales: Sclerotiniaceae). Therefore, the main emphases of this chapter will be given to these two problems and the management of them. Several other global pest and diseases commonly cause problems in vineyards, such as mealy bugs (Signoret) (Planococcus ficus Hemiptera: Pseudococcidae), Japanese beetles (Newman) (Popillia japonica Coleoptera: Scatabaeidae), mildew, black rot and leaf spot. However, no approaches on enhancing naturally occurring ecosystem services have been used to control them. Alternative habitat manipulation techniques than the local environmental manipulations discussed here to control B. cinerea have recently been reviewed by Jacometti et al. (2010).

Leafrollers and Botrytis cinerea in the vineyards

Two of the main yield-reducing problems in vineyards are leafrollers, especially the highly polyphagous light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) and the fungus, B. cinerea. The leafroller larvae feed on new shoots, flowers, stalks and leaves.

Leafroller management methods in many vineyards involve the use of synthetic broad-spectrum insecticides. These are applied on a calendar basis with little regard to pest abundance (Gurr et al., 2007). In California, about 10 million kg of active ingredients of pesticides are used annually to control pest pressures in wine grapes. Despite an overall decrease in all pesticide usage across commodities, in wine grapes there has been a 3% increase in active ingredients usage over the last year (Schwarzenegger et al., 2010).

Leafroller larvae not only damage the grapevines but are one of the factors making the grapes more susceptible to infection by botrytis, causing bunch rot in the damaged bunches. Bunch rot in New Zealand may cause midseason losses exceeding 20% and in very wet seasons may cause complete crop losses. The fungus can also affect flowers, leaves, buds, shoots, stems and/or fruits, often limiting plant development, fruit-set, yield and fruit quality. Botrytis is most commonly managed through canopy pruning and the prophylactic use of fungicides (Jacometti et al., 2010).

Habitat modification to enhance naturally occurring pest control

Both the development of resistance among the pest organisms and public concerns of the effects of the synthetic chemicals on human health and the environment have made high agrichemical input management strategies undesirable. Consequently, alternative methods to control the problem species have been developed. These often rely on the deployment of habitat modification methods to enhance the existing controlling mechanism.

Floral resource supplementation as a form of habitat modification

One way to potentially enhance the biodiversity within a vineyard and, at the same time, increase biological control of pest species is through the application of CBC. In CBC, natural enemies of pests are provided with floral resources. Growing non-crop plants, such as flowering plants within or around the crop from which natural enemies can benefit, may enhance their controlling efficiency of the pest (Tylianakis et al., 2004). CBC is based on Root’s ‘enemies’ hypothesis where natural enemies are more abundant in diverse crop environments (Root, 1973). This implies that habitat management in the form of increased diversification can be used to conserve and enhance natural enemies (Jonsson et al., 2010).

In CBC, omnivorous natural enemies are provided with alternative food sources, such as nectar and/or pollen. This may prevent them from starving or emigration while prey/ host densities are temporarily low in the area. The floral supplementation may also increase longevity, fecundity and other components of ‘ecological fitness’, which may in turn increase the pest controlling efficiency of the natural enemies.

One way to reduce the damage by leafrollers is by increasing the abundance of parasitoids and predators attacking the herbivore through habitat modification in the form of floral resource supplementation. These resources are aimed to increase the ‘ecological fitness’ of natural enemies and subsequently, hopefully lead to increased biological control of the pest through top-down mechanisms.

In New Zealand, the most common natural enemy attacking leafroller larvae is an endoparisitic braconid parasitic wasp, Dolichogenidea tasmanica (Cameron) (Hymenoptera: Braconidae). This parasitoid also controls the leafroller population in Australia together with the egg parasitoid Trichogramma carver (Carver) (Hymenoptera: Trichogrammatidae), the techinid fly Voriella uniseta (Malloch) (Diptera: Tachinidae), and the larva of lacewings such as Micromus tasmaniae (Walker) (Neuroptera: Hemerobiidae) (Gurr et al., 2007).

Floral resources commonly used as a habitat manipulation tool is buckwheat Fagopyrum esculentum (Moench) (Ploygonaceae) and alyssum Lobularia maritima (L.) (Brassicaceae). These have nectar and pollen that is easily accessible by natural enemies of herbivores and tend...