13.0 URBAN AND AGRICULTURAL UNITS
Typically a mixture of farmlands where human agricultural practices of plowing, fertilization and non-native crop production has resulted in long-term soil and/or vegetation changes.
Generally cultivated fields are located on flat to gently rolling terrain. Soil types and local climatic factors influence the types of crops which can been grown. The majority of the lower elevation plateaus and floodplains in the province are used for agriculture.
Two major uses of cultivated fields are as cropland or as pasture. Pasture land is created by clearing of the land. This is sometimes followed by seeding, depending on the intensity of the initial disturbance and successional pattern of the area. Continual grazing often leads to the introduction of many non-native species.
Croplands are much more intensively managed, including plowing and fertilizing. This has long term effects on the soil, often changing the vegetation climax potential for the area. Irrigation is often associated with both types of agriculture, particularly in drier regions.
Perrennial shrubs or uncut/ungrazed grasses are often found along the irrigation ditches, fences and hedgerows that form the boundary lines of these open agricultural lands.
The shape, size and growing patterns of the vegetation found on cultivated fields varies considerably. It is mainly dependent on plant species and climate. Most species are annuals planted in the spring and harvested in late summer. The specifics of germination and harvest time reflect the local climate and the species planted. Crop rotation is also a factor in the composition of these fields, as it is used to conserve soils and maintain productivity.
Cultivated fields are typically associated with or located adjacent to orchard/vineyard units (OV) and urban units (UR). They are also usually associated with aquatic habitats including large lakes (LL), small lakes (LS), reservoirs (RE) and shallow open water (OW).
Typically an area where mining exploration is presently taking place or an area where mining has recently been completed.
Mining activity occurs in all regions of the province, covering large or small areas, depending on the minerals which are desired and the terrain of the chosen area. Open pit mining is a common method used for mineral extraction. Basically, open pit mines are holes in the ground, varying in size and shape, which are open to the sky and have been created for the purpose of extracting minerals or aggregates (including gravel pits). Mines can also be in the form of complex underground tunnels, with only a few tunnels that actually connect to the surface, often via a central mine shaft.
Another common feature of associated with mining activity are mine tailings or rubbly mine spoils. These are areas containing the waste rock or overburden which is discarded in the extraction of ore in a mining operation.
Typically an agricultural area used for growing hard and soft fruit crops, with some form of symmetrical arrangement of the tress, shrubs or vines.
Concentrated in very arid regions of the province including the river valleys of the south Fraser, Thompson and Similkameen Rivers, the Okanagan Valley and southeastern Vancouver Island. Typically orchards and vineyards are associated with the Coastal Douglas-fir, Interior Douglas-fir, Ponderosa Pine and Bunchgrass biogeoclimatic zones.
Orchards are typically open single species tree dominated habitats. Depending on species and pruning method, most trees are low and bushy, less than 5m in height, with an open understory to facilitate harvest. Very often trees are arranged in a linear pattern with uniform spacing. The understory consists of low growing grasses and other herbaceous plants or managed to prevent understory growth entirely.
Vineyards are also single species units planted in rows, with plants usually supported by wood or wire trellises. Vines are typically intertwined along each row but spaced between rows. Understory growth is usually prevented along the rows and managed between rows to control soil erosion.
Typically this unit is associated with other anthropogenic units including cultivated fields (CF), reservoirs (RE) and urban (UR) centres. It is also associated with aquatic habitats such as large lakes (LL), small lakes (LS) and shallow open water (OW).
Orchards and vineyards are associated with rich fluvial materials on flat areas located in the valley bottoms, on terraces or gentle valley slopes. Most sites are subject to a variety of irrigation methods.
Typically a mined area or mine tailings that have plant communities composed of a mixture of agronomic grasses and forbs and native plants.
Mining activity has taken place in all regions of the province, covering large and small areas, depending on the minerals which were desired and the terrain of the chosen area. Reclaimed mines usually contain a mixture of native and introduced plant species. The density and composition of these communities is related to the age and location of the site, as well as the amount of disturbance that resulted from the mining activities.
In some areas of the province, the disturbances caused by mining activities may have provided the ideal conditions for particular native plant species, which have flourished since the operation ceased. However, in other heavily disturbed areas, agronomic species may have been seeded in order to stabilize the soils and have subsequently dominated these previously mined sites.
Typically a linear-shaped land area dedicated to some form of above ground system for carrying products from one point to another, including roads and railways.
Commonly occur in low to middle elevation biogeoclimatic units throughout the southern half of the province. In more northerly locations they are not as widespread. Transportation corridors tend to be associated with communities, linking one community to another and to resource related activities.
Transportation corridors may create physical barriers or boundaries on the surface of the ground. Many roads are both paved and fenced, though many less traveled roads are graveled, primarily used for activities related to forestry, agricultural, mining and petroleum exploration and hydroelectricity. These less traveled roads do not seriously divide vegetated areas, but typically transportation corridors are subject to ongoing human disturbances.
Typically a linear-shaped land area dedicated to some form of above or below ground system for carrying products from one point to another, including transmission lines and pipeline.
Commonly occur in low to middle elevation biogeoclimatic units throughout the southern half of the province. In more northerly locations they are not as widespread in occurrence. Transmission corridors tend to be concentrated around hydroelectric systems.
Transmission corridors, such as gas pipelines and transmission lines, do not form physical barriers on the ground. The vegetation associated with this unit is usually managed and kept in an early successional stage; most often a grass or shrub dominated community. In heavily disturbed areas, grasses or legumes are often seeded to stabilize the soils.
Typically transmission corridors are less frequently traveled and not subject to the influences of constant human disturbances.
Typically a mixture of human-influenced habitats that includes residential areas, urban areas, but excludes major agricultural lands.
Urban development is not limited to specific regions or particular physical environments. However, the majority of urban centres are situated at low elevations and near the coast, large rivers or lakes.
Urban ecosystem units are dominated by urban and rural housing, commercial cores and industrial developments. Vegetative diversity is provided by residential housing, parks, green belts and cemeteries. Each provide a wide variety of annual and perennial herbs, grasses, shrubs and trees in combination with components of existing natural ecosystems.
Forested areas do exist, often containing a variety of tree species, depending on what was planted. The understory also varies in structure and composition depending on the canopy composition and degree of maintenance.
Along many roads there are usually trees, shrubs or grasses planted. The desired development reflects the spacing, type and size of species planted.
Lawns, shrubs and a variety of shade trees are common in all residential areas. All three are typically composed of a variety of species and subject to scheduled maintenance. This maintains a continuous and uniform ground cover.
Over time most urban vegetation is relatively static in species composition because of maintenance. However, shrub and tree species found in urban areas will grow in size and possibly change the composition of much of the understory vegetation. Secondly, the majority of urban centres have a variety of introduced species planted within the city. Very often introduced species outcompete natural vegetation and slowly take over the ecosystems surrounding urban centres. The degree of change is dependent on the amount of maintenance and the desired vegetation structure and form.