Biodiversity is defined as "the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic systems and the ecological complexes of which they are a part; this includes diversity within species, between species and of ecosystems."¹ Biodiversity is considered essential for the resilience of ecosystems. Many ecosystem processes regulate conditions for life. Holling² argues that this role provides the rationale for giving priority to rehabilitation, protection of ecosystems and land use management. Resilience enables ecosystems to return to a steady state after being subjected to an unusual event denoted as being a "surprise". The ecosystems may not necessarily return to the same state as before. In other words, ecosystems are subject to discontinuous change. However, there remains the risk that intervention in ecosystems by humans can result in a reduction of their resilient nature rendering them incapable of dealing adequately with unusual events. Holling describes the situation with respect to ecosystems as follows:

"Ecosystems have a natural rhythm of change, the amplitude and frequency of which is determined by internal processes and structures in response to past external variabilities. These rhythms alternate periods of increasing organization and stasis with periods of reorganization and renewal. They determine the degree of productivity and resilience of ecosystems.

Modern technological man affects these patterns and their causes in two ways. First, traditional resource-management institutions constrain rhythms by restricting them temporally and homogenizing them spatially. Internal biophysical relationships then change, leading to systems of increasing fragility, i.e. to a reduced resilience. Moreover, modern man and his institutions operate with a different historical rhythm which can mask indications of slowly increasing fragility and can inhibit effective adaptive responses, resulting in the increased likelihood of internally generated surprises, i.e. crises. Second, the increasing extent and intensity of modern industrial and agricultural activities have modified and accelerated many global atmospheric processes, thereby changing the external variability experienced by ecosystems. This imposes another set of adaptive pressures on ecosystems when they are already subject to local ones. As a consequence, locally generated surprises can be more frequently affected by global phenomena, and in turn can affect these global phenomena in a web of global ecological dependencies." ³

Loss of biodiversity has profound implications for development. Biological resources are renewable and output can be increased under appropriate management. Natural habitats which can maintain productivity without significant management have the ability to provide means for human survival. Highly diverse natural ecosystems also provide important ecological services. These include maintaining hydrological cycles, regulating climate, contributing to the process of soil formation and maturation, storing and cycling essential nutrients, absorbing and breaking down pollutants and providing sites for inspiration, tourism, recreation and research. While nature has some built-in redundancy few data are available on which species are particularly important in the functioning of ecosystems so that the actual value of specific losses of biodiversity is not available. There is need, however, to at least maintain biodiversity by maximizing the number of different species conserved in sufficient quantities to assure survival⁴.

The many values of biodiversity and its importance for development suggest why biodiversity conservation differs from traditional nature conservation. Biodiversity conservation entails a shift from a defensive posture to an offensive effort seeking to meet peoples' needs from biological resources while ensuring the long-term sustainability of earth's biotic wealth. It involves not only the protection of wild species, but also the safeguarding of the genetic diversity of cultivated and domestic species and their wild relatives. This goal applies to modified and intensively managed ecosystems as well as natural ones and is pursued in the human interest and for the human benefit. Conservation of biodiversity seeks to maintain the human life support system provided by nature and the living resources essential for development⁵.

Biological resources support development in virtually all sectors and affect those who live in cities as well as those in the country. Agriculture under good management is an example of the management of a modified ecosystem to yield what is perceived to be optimal productivity. The system is inevitably somewhat impoverished as predators and competitors are eliminated or reduced and the population structure is altered in order to enhance yields. Yet it is ecologically sound and essential to human welfare. Such a system both affects and depends on the more natural ecosystems⁶.

Biodiversity may, therefore, be seen as an indicator of environmental health. Success in maintaining biodiversity must take into account both spatial and temporal factors. It is not, however, possible to ensure a constant level of biodiversity at a particular location over time. Agriculture by its close attachment to the land is in a position to greatly influence biological diversity on the prairies.

Agriculture has substantially changed the prairie landscape. Annual crops have replaced the grasses which previously covered the land. In fact, modern agriculture can be said to have had a greater impact on biodiversity in the Plains region than any other activity. As agriculture became more intensive, wetlands were drained, trees removed and grasslands cultivated. These actions, while being advantageous for the use of large modern equipment, effectively destroyed the habitat for many plant and animal species. In no area was this development more effective than on the open prairie. These actions were largely induced by public policy which directly or indirectly fostered expansion of the cultivated area. Indeed, more than 80 per cent of the prairie landscape has been altered by agriculture. Drainage for use in agriculture has been responsible for 85 per cent of the total land drained. The impact on the bird population because of following this course has been significant since the sloughs and small lakes drained provided the habitat for more than 60 percent of the waterfowl on the continent. It should therefore not be surprising that waterfowl populations have declined over time. Continued expansion of the area in agriculture, whether by removal of indigenous prairie trees or extension into the parkland area, serves to reduce the habitat for wildlife. Animals also suffer from the reduction in habitat, often being forced to retreat into more remote areas. In many parts of the prairies native vegetation has become a thing of the past, stimulating organizations to strive to protect any areas remaining.

The extent to which agriculture on the prairies has changed the landscape has been described by Gauthier and Henry⁷ . Only one percent of the tall grass prairie, 18 percent of the short-grass prairie, 25 percent of the mixed grass prairie and 25 percent of the aspen parkland remain. Furthermore, conversion of these lands to agriculture continues, as a result largely of agricultural policy. The remaining areas of untouched wildlife habitat have become progressively more fragmented, more isolated, and often too small to sustain viable populations of species that had once been abundant. In no case is this predicament more evident than in that of wetlands, which are said to be disappearing at the rate of 0.5 percent annually in Alberta.

On the prairies, 60 percent of the wetland basins and 80 percent of the habitat surrounding these basins are affected by farming each year. This occurrence has a significant impact on waterfowl. Grazing by cattle and other domestic animals reduces plant cover and the supply of food and shelter for meadow and grassland species of mammals, birds and invertebrates. On the other hand, some forms of wildlife thrive under the conditions arising from agriculture. Farm shelterbelts provide cover for numerous species of birds. Other species have benefited from the increased feeding opportunities provided by agricultural crops. These include ducks, geese, sandhill cranes, robins and blackbirds. However, biodiversity remains threatened by agricultural operations, as 12 of the 62 species of plants considered endangered are wetland species. Furthermore, diseases of farm livestock have been known to be transmitted to native animals with devastating results. Conversely, diseases can be transmitted from native animals to those on the farm.

Maintenance of the current level of biodiversity on the prairies, which reflects the impact of agriculture on habitat, cannot be considered particularly difficult. Biodiversity in terms of numbers of different species on the prairies has not been so much affected as have the numbers remaining within given species. The factors contributing to the decline in numbers include agricultural policies, regional development plans, institutional structures, world trade, characteristics unique to the rural economy and the world view prevailing in rural areas⁸.

Additional sites of interest:

U.S. National Biological Service

Footnotes:

1. As quoted by R. Sopuck, Canada's Agricultural and Trade Policies: Implications for Rural Renewal and Biodiversity, July 1993. p. 14.
   
2. C.S. Holling. "The Resilience of Terrestrial Ecosystems: Local Surprise and Global Change", Sustainable Development of the Biosphere, W.C. Clark and R.E. Munn eds., undated.
   
3. Holling. p. 313.
   
4. J.A. McNelly. "The Biodiversity Crisis: Challenges for Research and Management," Conservation of Biodiversity for Sustainable Development, O.T. Sandlund et al eds., Scandinavian University Press, 1992.
   
5. World Resources Institute et al. Global Biodiversity Strategy, United Nations, 1992.
   
6. J.A. McNelly. Economics and Biological Diversity, International Union for Conservation of Nature and Natural Resources, Gland, Switzerland, 1988.
   
7. D.A. Gauthier and J.D. Henry. "Misunderstanding the Prairies", Endangered Spaces: The Future for Canada's Wilderness, M. Hummel ed., Toronto, 1989. pp. 183-185.
   
8. Sopuck. p. 16.
   

INDEX:

Great Plains Home Page

Measurement of Sustainability

Land Use

Degradation of Soil Resources

Preservation of Biodiversity

Water Use and Quality

Rural Communities

Economic Situation

Use of Common Property

Impacts of Trade on Sustainability

Federal & Provincial Policies

Global Changes