BCB 322:Landscape Ecology

Lecture 1: Introduction

What is a landscape?• “Total character of a region” von Humboldt, 19th 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. 1994

• 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

1.11949002775

1.05152222694

1.857100276593

3.217973611252

1.74536523731

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: 145-162

• 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. 43-74.

• Spies, T. Ripple, W.J. & Bradshaw, G.A. (1994) Dynamics & pattern of a managed coniferous forest landscape in Oregon. Ecological Applications 4:555-568

• Whittaker, R.H. (1977) Evolution of species diversity in land communities. Evolutionary Biology 10: 1-67

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