BCB 322: Landscape Ecology Lecture 1: Introduction

What is a landscape? “Total character of a region” von Humboldt, 19 th century “landscapes … in their totality as physical, ecological & geographical entities, integrating all natural & human patterns & processes” Naveh, 1987 “..a heterogeneous land area composed of a cluster of interacting ecosystems that is repeated in similar form throughout” Forman & Godron, 1986 “a particular configuration of topography, vegetation cover, land use & settlement pattern which delimits some coherence of natural & cultural process & activities” Green et al, 1996

Landscape In general, landscape can be defined as a broad area which is homogenous for some defined characters, in which we are able to perceive relationships between structural & functional components. Translated into parameters which we can analyse, we want to: –Look at the physical layout of an area –Establish what has caused it to look that way –Understand how this impacts on the organisms (at a population level) that live in the area

What is landscape ecology? The study of patterns & processes that occur across a landscape Often related to ecosystems that have been transformed through human activity Allows planning for conservation purposes Requires & promotes understanding of the importance of spatial arrangement of patterns & processes

What is landscape ecology? A complex area, integrating aspects of many different fields, including: –geography –botany –zoology –animal behaviour –ecology –landscape architecture –sociology & human pressures

Perspectives As landscape ecology developed it became clear that there were at least 3 major perspectives in which scientists were operating: –Human: grouping landscape into functional entities with meaning for human interactions –Geobotanical: spatial distribution of biotic & abiotic components of the landscape (soil, ‘perceived’ plant landscapes, distribution of plant communities) –Animal: conceptually related to human scale, although scale can be highly variable, depending on organism

Perspectives Human aspect may be most complex (better data, integrates socioeconomic factors) Dangerous to consider anthropocentric viewpoint exclusively Ignoring ecological criteria/models benefits only humans & human-adapted animals Behavioural ecology & perceptual range Integration of other perspectives requires knowledge about population dynamics & good ecological models Properly structured LE allows change prediction

Change prediction Change prediction could be essential for the survival of entire ecosystems Public/private forest land in Oregon Spies et al Black = pine forest, white = other woodlands

Study Scale a)Hedgehog (Erinaceus europaeus) 300x300m b)Fox (Vulpes vulpes) 3x3km c)Wolf (Canis lupus) 10x10km Farina, 1998

Study Scale Grain: minimum area at which the study organism interacts with the patch structure of the landscape) Extent: coarsest scale at which they react Space: the final frontier Rodenberry, 1970; Kareiva, 1994 Spacing: (spatial arrangement) the scaled property of living organisms (individuals, populations, communities) in response to non-uniform resource distribution & competition in space & time

Study Scale Landscape ecological studies are scale dependent. Although we study complicated systems, it is usually in relation to a reference organism, which determines the study scale Human scale: landscape comprises heterogeneous mosaic of patches (ecotopes), in which we look at physical, biological & cultural elements Ant: drivers of landscape functions for an ant will be much finer – resource availability is much more local, so we need to scale down our study to the beetle’s assumed perception

Landscape structure Landscape is intrinsically heterogeneous at all scales Hence, this mosaic is represented by patches inserted into a matrix (dominant cover) Patches of several community types (higher level for biological complexity) Spatial arrangement of patches, variance in quality & proximity, proportion in the landscape, all modify behaviour of dependent organisms

Landscape Structure L/2√AπAreaPerimeterPatch

Landscape classification Generally used for studying interaction between human activity & landscape. Depends on large amounts of information –Aerial photographs –Satellite images –Cadastral maps –Geological, hydrological & soil maps –Geographic & biothematic maps (eg: vegetation, land use, fire frequency) This information is integrated in Geographical Information Systems (GIS)

Patch types Structural: soil type overlapped with vegetation Functional: physical descriptor (altitude, light, temperature, rainfall). Includes ecotope Resource: animal ecology – equal or smaller than home range Habitat: distinct plant communities (usually larger than home range) Corridor: controversial, but is a section of mosaic used by organism to move, or disperse

Landscape Classification Classification is heirarchical 3 habitat patches overlaid with small mammal territories Territories divided to show resource patchiness Ostfeld, 1992

Landscape classification Complete study area (macrochore) Hydrological zones/catchments (mesochore) Geomorphological zones/physiotopes (mesochore) Vegetation zones (microchore) Each vegetation zone comprises several ecotopes, which are the homogenous units for a specific vegetation type (eg: acacia thicket) Canters et al, 1991

Landscape classification Interestingly, although this classification system is frequently used, scales may depend from site to site. Comparing alpine, hilly & plain areas, topographic complexity may play a significant role However, it allows comparison of different studies, and can be changed for non-human scales as well. Diversity measurements (Whittaker, 1977) correspond to these scales (α-diversity -> ecotopes… ε-diversity -> macrochores) In urban areas, the ecological feedback component of the hierarchy breaks down

Summary Landscape ecology is a young discipline, born in central and eastern Europe after WWII Integrates geobotanic, animal & human components Makes use of several theories (island biogeography theory, hierarchy theory) and combines them with metapopulation and source-sink population theories It is essentially spatial in nature Behavioural ecology is strongly linked to landscape ecology Patches are the emerging elements in the landscape

References Canters, K.J., den Hereder, C.P. de Veer, A.A., & de Waal, R.W. (1991), Landscape-ecological mapping of the Netherlands. Landscape Ecology 5: Farina, A. (1998) Principles and Methods in Landscape Ecology, Chapman & Hall, Cambridge, pp.235 Ostfeld, R. (1992), Small mammal herbivores in a patchy environment: individual strategies and population responses, in: Hunter, M.D., Ohgushi, T. & Price, P.W. (eds.), Effects of resource distribution on animal-plant interaction, Academic Press, San Diego, San Diego, pp Spies, T. Ripple, W.J. & Bradshaw, G.A. (1994) Dynamics & pattern of a managed coniferous forest landscape in Oregon. Ecological Applications 4: Whittaker, R.H. (1977) Evolution of species diversity in land communities. Evolutionary Biology 10: 1-67

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