Dynamics of agricultural practices on ecosystem services : An overview

Green Farming Vol. 2 (5) : 321-324 (February, 2009)

Dynamics of agricultural practices on ecosystem services : An overview SHAKEEL A. KHAN

1*

2

and D. K. SHARMA

Division of Environmental Sciences, Indian Agricultural Research Institute, Pusa, New Delhi - 110 012 (India)

Abstract . Agriculture is a keycard cruise of the global economy. It ropes the livelihoods and subsistence of the largest number of people worldwide and is vital to rural development and poverty alleviation, as well as food and nonfood production. About 70% population of India depends upon this ancient occupation. The main challenge for the agricultural sector is to secure enough high-quality agricultural production to meet demand; conserve biodiversity, sustain ecosystem services and improve human health and well-being. As human populations grow, so do the resource demands imposed on ecosystems and the impacts of our global footprint. Agricultural practices have environmental impacts that affect a wide range of ecosystem services, including water quality, pollination, nutrient cycling, soil retention, carbon sequestration, and biodiversity conservation. In turn, ecosystem services affect agricultural productivity. There is no single, globally applicable sustainable management solution for agriculture. This is because agricultural practices depend on site-specific variables, such as climate, ecology, geography, demography, affluence and regulation. Nonetheless, sustainability principles can be applied across different management systems by taking astute consideration of ecosystem services. Key words : Agriculture, biodiversity, ecosystem, ecosystem services, sustainability.

INTRODUCTION It is now well identified that agricultural activities affect and are affected by the class of the environment and vice versa. Understanding how agriculture impacts ecosystem services, which in turn affect agricultural productivity, is of particular importance because of agriculture is a dominant form of land management (Dale and Polasky 2007). Food production will have to increase by 50 per cent to feed a population of nine billion people by 2050 (FAO, 2007). This brings agricultural production under extreme pressure. Alongside the demands on the agricultural sector for increased production, there are also increasing expectations and needs for cultivation practices to be sustainable. Globally, it is estimated that 38 per cent of land is in agricultural uses (FAO, 2007), and excluding boreal lands, desert, rock and ice, this amount rises to 50 per cent due to exponential population growth (Tilman et al., 2002). During the first 35 years of the Green Revolution, global grain production doubled, greatly reducing food shortages, but at high environmental cost (Tilman et al., 2001). Agriculture practices affects ecosystems by the use and release of limiting resources that influence ecosystem functioning (nitrogen, phosphorus, and water), release of pesticides, and conversion of natural ecosystems to agriculture. Population explosion and per capita consumption are assumed to be the two greatest drivers of global environmental change and affecting the ecosystem services. Global population, which increased 3.7-fold during the 1

2

Scientist (Sr. Scale), Sr. Scientist

*Correspondence

20th century, to 6 billion people is forecast to increase to 7.5 billion by the year 2020 and to about 9 billion by 2050 (World Population Prospects: The 1998 Revision). During the next 50 years, which is likely to be the final period of speedy agricultural expansion, demand for food by a wealthier and 50 per cent larger global population will be a major driver of global environmental change to affect he ecosystem services. This would be accompanied by 2.4-to 2.7-fold increases in nitrogenand phosphorus-driven eutrophication of terrestrial, freshwater, and near-shore marine ecosystems, and comparable increases in pesticide use (Tilman et al., 2001). Noteworthy scientific advances and regulatory, technological, and policy changes are needed to control the implication of agricultural practices on ecosystem services. Sustainable agriculture would require for the production of both food and ecosystem services. But appropriately farmers and other agriculturalists will require the ability to accurately measure ecosystem services in a verifiable quantitative manner.

ECOSYSTEM SERVICES (ES) Humankind benefits from a multitude of resources and processes that are supplied by natural ecosystem. Collectively, these benefits are known as ecosystem services (ES) and include products like clean drinking water and processes such as the decomposition of wastes. Daily (1997) has defined ecosystem services as “the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life”. The natural ecosystem

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accommodates people with goods and services that are fundamental to human wellbeing. Dent to the ecosystem is seriously degrading these services and this will have economic implications. The Millennium Ecosystem Assessment (MEA) classified ecosystem services into four broad categories: = Supporting services, such as nutrient cycling, oxygen

production and soil formation. These underpin the provision of the other 'service' categories. = Provisioning services, such as food, fiber, fuel and water. = Regulating services, such as climate regulation, water purification and flood protection. = Cultural services, such as education, recreation, and aesthetic value.

Ecosystem Services

Provisioning Services = Food = Fiber = Fuel

Oxygen production

Regulating Services = Climate = Regulation = Pollination

how agricultural ecosystems are managed at the site scale and on the diversity, composition, and functioning of the surrounding landscape (Tilman, 1999). The scales at which services are provided to agriculture are also critical to how management decisions are made. Many key organisms that provide services and dis-services to agriculture do not inhabit the agricultural fields themselves. Rather, they live in the surrounding landscape or they may move between natural habitats, hedgerows and fields (Zhang et al., 2007). Table 1 summarizes the major actors and scales of provision for the ES and EDS and also highlights the importance of a farm's landscape context in managing many of the supporting and regulating ES and EDS. For example, landscapes that contain diverse habitat types typically are more compatible for beneficial insects and in most cases result in enhanced biological control of pests and provision of pollinators. So, we can now understand that agriculture and ecosystem services are interrelated in at least three ways:

Supporting Services Nutrient cycling

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Soil formation

Cultural Services Recreation = = Education = Aesthetic value

Human well – being and sustaining the Nature

Fig. 1. Classification of ecosystem services from the Millennium Ecosystem Assessment Assessment As such, agricultural management needs to not only further increase the productivity of existing farmland to meet demand by adapting good and efficient management practices, but also embrace the three pillars of sustainability i.e. ecosystem functioning, social adaptability and economics.

Agriculture and Ecosystem services Agriculture both provides and receives ecosystem services. Agro-ecosystems are primarily juggled to optimize the provisioning ES of food, fiber, and fuel (Swinton et al. 2007). In the process, they depend upon a wide variety of supporting and regulating services, such as soil fertility and pollination (MA, 2005), that determine the underlying biophysical capacity of agricultural ecosystems (Wood et al., 2000). Agriculture also receives a group of ecosystem dis-services (EDS) that reduce productivity or increase production costs (e.g., herbivore and competition for water). The flows of these ES and EDS rely on

(1) Agro-ecosystems generate beneficial ecosystem services such as soil retention, food production, and aesthetics; (2) Agro-ecosystems receive beneficial ecosystem services from other ecosystems such as pollination from nonagricultural ecosystems; and (3) Ecosystem services from non-agricultural systems may be impacted by agricultural practices. To make the concept of ecosystem services equipped with reverence to agro-ecosystems, it requires a way of measuring ecosystem services. To be really useful in management and policy discussions, however, there must be a way to measure how ecosystem services change as a function of changing agricultural practices. This requires a thorough understanding how ecological systems function, both under current conditions and how these functions might change with different management regimes (Dale and Polasky 2007). Crop and livestock production are the best quantified services from agriculture. India is having largest population of livestock and 2nd largest population of the world after China and given more importance to increase of productivity to meet the demand of growing population. Our grain production reached at the mark of 210 MT, greatly reduced food shortages, made us self sufficient, but at high environmental cost. A great deal of the increase in production came from increasing yields through a gigantic increase in application of chemical fertilizers and pesticides and water from irrigation systems.

Need of interpreting indicators of ecosystem services Many researchers have used ecological indicators to quantify the magnitude of change, amount of exposure to change, or degree of response to the exposure (Hunsaker and Carpenter, 1990). The purposes of ecological indicators include assessing the condition of the environment, monitoring trends in conditions over time, providing an early warning signal of

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Dynamics of agricultural practices on ecosystem services : An overview

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Table 1. Major ecosystem services (ES) and dis-services to agriculture (adapted from Zhang et al., 2007) ES or EDS

Field

a

Farm

b

Landscape

c

Region/globe

d

Services (ES) Soil fertility and formation, nutrient cycling

Microbes; invertebrates communities; legumes

Vegetation cover

Soil retention

Cover crops

Cover crops

Riparian; vegetation; flood plains

Pollination

Ground-nesting bees

Bees; other pollinating animals

Insects; other pollinating animals

Pest control

Predators and parasitoids (eg., spiders, wasps)

Predators and parasitoids (eg.spiders, wasps, birds, bats)

Water provision and purification

Vegetation around drainage and ponds

Genetic diversity

Crop diversity for pest and diseases resistance

Climate regulation

Vegetation influencing micro-climate (e.g. agroforestry)

Vegetation cover in watershed

Vegetation cover in watershed

Vegetation cover in watershed Wild varieties

Vegetation influencing micro-climate

Vegetation influencing stability of local climate; amount of precipitation; temperature

Vegetation and soils for carbon sequestration

Dis-services (EDS) Pest damage

Insects; snails; birds; mammals; Insects; snails; birds; mammals; Insects; snails; birds; fungi; bacteria; viruses; weeds fungi; bacteria; viruses; weeds mammals; range weeds

Competition for water from other ecosystems

Weeds

Competition for pollination Flowering weeds services

Vegetation cover neat drainage ditches

Vegetation cover in watershed

Flowering weeds

Flowering plants in watershed

Vegetation cover in watershed

a

Services provided from within agriculture field themselves.

b c

Services provided from farm property, but not necessarily in active field themselves. Services provided from landscape surrounding typical farms, not from farmers property.

changes in the environment, and diagnosing the cause of an environmental problem (Cairns et al., 1993). Because no one indicator can meet all of these goals, we anticipate that a set of indicators will be needed to capture key attributes of ecological systems of interest (Bockstaller et al., 1997; Dale et al., 2004). Yet multiple, interdependent ecosystem services and values present both conceptual and empirical research challenges (Turner et al., 2003). There must be a set of ecological indicators for ecosystem services both from and to agriculture should be considered as they relate to all pertinent spatial resolutions. Ecological indicators are meant to provide a simple and efficient means to examine the ecological composition, structure, and function of complex ecological systems.

Ecological indicators A challenge in developing and using a suite of ecological indicators for ecosystem services interrelated with agriculture is determining those indicators that adequately characterize the complexities of the entire system yet are simple enough to be effectively and efficiently monitored and modeled (Dale et al., 2004). Such indicators must be closely linked to, and analytical

d

Services provided from broader region or globe.

of, changes in ecosystem services. Dale and Polasky (2007) have suggested following criteria for ecological indicators of ecosystem services related to agriculture. = Indicator should be easily measured = Should be sensitive to changes in the system = Respond to change in a predictable manner = Should be anticipatory, that is, signify an impending change

in key characteristics of the ecological system = Predict changes that can be averted by management

actions = Indicator should be integrative = Have known variability in response

Developing a set of indicators that are both assessable and united to the provision of ecosystem services is one way to make progress on tracking changes in ecological systems and how this might affect the course of ecosystem services. A key challenge is to assemble the appropriate suite of indicators for ecosystem services relevant to a particular agro-ecosystem that captures key ways that agriculture activities can affect and are affected by ecosystem services. All of these types of indicators must be considered in order to have full

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understanding of agriculture's effects on ecological systems, but in the end only a select few will be able to be gauged because of resource limitations. By focusing on ecosystem services provided to and affected by agriculture, the relationship of agriculture practices to the ecosystems in which they occur will be made more clearly. Obviously people value the food provided by agriculture, but other benefits can be important as well. Furthermore, being able to quantify how agriculture can affect ecosystem services is necessary to perform a full accounting of the costs and benefits of agriculture both worldwide and in specific locations (Tilman et al., 2002). Understanding the benefits and costs of different types of management practices is necessary in order to be able to establish and maintain sustainable agro-ecosystems. After going through today's agriculture scenario, here we suggest some services which must be considered are protection of ground water quality, surface water quality, air quality, soil quality, non-renewable resources, biodiversity, and landscape quality and indicators measured in each field should be nitrogen, phosphorus, carbon, pesticide, irrigation, organic matter, GHGs, energy, crop diversity, soil structure, soil cover and ecological structures. As suggested by Dale and Polasky (2007), the indicators relate to one or more of these services.

CONCLUSION Promoting the healthy functioning of ecosystems ensures the resilience of agriculture as it intensifies to meet the stress of growing demands for food production. Climate change and other stresses have the potential to make major impacts on key functions, such as pollination and pest regulation services. Learning to strengthen the ecosystem linkages that promote resilience and to mitigate the forces that impede the ability of agro-ecosystems to deliver goods and services remains an important challenge. The destruction and exploitation of the ecosystems and natural resources appears economically rational, as many of the values of the ecosystem or natural resources are not recognized in decision-making. Similarly the values of ecosystem services are not fully reflected in our national accounting systems. In India, public policies related to development and conservation seldom overlaps. That is the basis of the environmental problem that we face today. There is an intense need to understand the dynamics of ecosystem services in relation to agriculture. And for these we have to develop the site specific indicator for agricultural practices because it would help to target key environmental problems and opportunities for improvement. Indicators can be helpful in designing effective farming systems and in monitoring them. In a landscape context, indicators can be useful in evaluating the overall ecosystem services provided by agricultural lands in contrast to other land uses. In sum, agricultural ecosystems offer newly recognized potential to deliver more diverse ecosystem services and mitigate the level of past ecosystem disservices.

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