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Land(scape) classification (continued) approaches applications. Land(scape) classification. ecosystematic. climatic. physiographic. vegetative. Climatic classification: -climate naturally dictates the major vegetation zones -useful at broad scales, but land units too broad
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Land(scape) classification (continued) • approaches • applications
Land(scape) classification ecosystematic climatic physiographic vegetative
Climatic classification: -climate naturally dictates the major vegetation zones -useful at broad scales, but land units too broad for local level uses
Physiographic classification: -based on landform and soils -based on relatively permanent features, so can be more long-lasting than e.g. vegetation classification alone -lends itself to remote sensing -of limited use for ecological purposes unless combined with vegetation
Vegetation classification: -based on vegetation physiognomy floristic composition -integrates the total environment (vegetation is largely determined by climate and physiographic factors…) -but, subject to change – vegetation form and composition also depends on time since last disturbance
Ecological Land Classification for Southern Ontario (new): Based on physiognomy (e.g. coniferous forest, thicket swamp) at coarse level, floristic composition (e.g. sugar maple-white ash deciduous forest type) at finer level
Ecosystem classification: -incorporates climate, vegetation, soils, landform -usually focuses on vegetation-soil units -more useful in changing landscapes -more useful for ecosyste-based management
Land classification systems can be parametric (”bottom-up”)… -classifies land units based on the value of selected parameters (e.g. soil nutrient levels, elevation, height of dominant plants, mean annual temperature) -precise, objective approach….but, difficult to select appropriate attributes and the ‘cut-off’ values between classes …or based on morphological appearance (“top-down”) -uses observations of topography, vegetation to distinguish different land units -can be more subjective…but more intuitive as it is based on obvious distinguishing features
-Moss has suggested classifying landscapes based on rates of different ecological functions (e.g. productivity, decay)
-Land classification is done for a purpose, not as an end in itself -choice of characteristics on which a classification system is based depends on the end use of the system -too many characteristics = small classes (few land units in each class) = less useful for making generalizations -too few characteristics = large classes = not specific enough
Choice of criteria should be based on: • Accessibility (easy to measure/observe) • Significance (how well does the characteristic distinguish one land unit from another?)
Applications of land classification systems based on ecosystem characteristics: -forest management -conservation -forest fire control
-different classes of jack pine forest may be more or less susceptible to fire -the Northwestern Ontario Forest Ecosystem Classification distinguishes between jack pine-dominated forests based on understory vegetation -the type of understory vegetation partly determines the burn potential of a forest patch -fire control personnel can better predict the behaviour of fire (potential for intensity, spread, etc.), and prioritize control efforts, using the FEC to map out jack pine forest types
-ecosystem classification can be used to plan habitat reserves in a managed landscape -setting aside a representative amount of each land type can help to ensure the protection of different habitat types -traditionally, reserves set aside on poor and/or inaccessible land
Categories of landscape elements: describing landscape structure • matrix • patch • corridor • mosaic • network • edge • interior • total habitat area • patch area • patch shape • connectedness • connectivity • heterogeneity • scale
Matrix: -the dominant, all encompassing element in the landscape Patch: -relatively homogenous areas of contrasting habitat patch matrix
Carolinian Region: pre-European settlement
Carolinian Region: Mid-1990s
Both the quantity and quality of patches of a given type will affect the ecological functioning of the landscape (e.g. for wildlife habitat) The habitat quality in a patch is related to its size and shape: -large patches have a high ratio of interior to edge compared to small patches
-for a given total area of a habitat type, fewer, larger patches will have less edge than numerous, small patches Total area: small patches =2 km2 (8 x 0.25 km2) Total perimeter length =14 km !! Total area: large patch =2 km2 Total perimeter length =5 km
-for a given patch area, a circular patch will have less edge than an elongated patch Total area: long patch =2 km2 Total perimeter length =6.84 Total area: circular patch =2 km2 Total perimeter length =5 km
Why do we care how much ‘edge’ there is? -different from interior -more influence from adjacent patches
In the case of forest patches in a fragmented landscape, edge habitat has: -different microclimate, e.g. more light availability -more ground vegetation -different species… more ‘pioneers’, opportunistic species
The ‘edge effect’ – different microclimate near forest edge vs. interior
The ‘edge effect’ – different plant community composition near edge
The ‘edge effect’ – can result in more diversity at the forest edge vs. interior forest old field
From a study of the effects of forest harvesting on landscape patterns in NB
Corridor: -linear elements, may stand alone or link patches together -not necessarily continuous…’stepping stones’ of habitat may also be considered corridors Network: a set of corridors on the landscape
Function of corridors: -provide connectivity between patches of habitat -increase the permeability of the landscape -(sometimes a distinction is made between connectivity and connectedness)
Function of corridors: -why is more connectivity usually desirable in fragmented landscapes? -is more connectivity always good?
Even in non-terrestrial ‘landscapes’…corridors aid dispersal between habitat patches (this result was found in an estuary, with marine invertebrates moving through corridors and patches of seagrass)
The ‘patch/matrix’ view has largely given way to the ‘mosaic’ view landscape composed of a collection of patches landscape is composed of patches of habitat within a ‘hostile’ matrix of non-habitat in the real world…the ‘matrix’ is just another habitat type derived from ‘islands in ocean’ analogy
Landscape pattern: -the spatial arrangement of the mosaic and networks -the scale or grain with which you view or consider the landscape also influences the pattern you perceive fine grain = lots of detail coarse grain = little detail beans corn cropland wheat hay young forest old forest forest
-what constitutes a patch in this photo….forest cover in general, or each different type of forest cover? -fine grain vs. coarse grain view depends on the question you are asking about the landscape, e.g. the organism you are concerned about