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Krumme Summer School 2006

FWU, Vol. 5, Participatory Watershed Management Plan 17

EFU - Ecological Functional Units:

A Basis for Sustainable Development Planning

Klaus Krumme, M.Sc.

Sustainable Development Group

University of Duisburg-Essen

E-mail: [email protected]

Abstract

Ecological Functional Unit (EFU) approach to sustainable development planning

differs from the conventional approaches related to development planning in that it

attempts to base the use of natural resources, be it conservation or economic

development or others, on the ecosystems natural functioning, itself determined by

the ecological key processes and structures of the particular ecosystems and thevariety of interconnections between them. With such an approach clusters of

landscape elements on various spatial scales can be accessed and evaluated to

assess their functions, capacities and limitations for development.

Key Words

Ecological Functional Units (EFU), Landscape Ecology, Landscape Analysis,

Homogeneity, Heterogeneity, Sustainable Development, Integrating Factors,

Pronounced Processing Zones (PPZ), Ecological Clustering, Natural Resource

Management

Introduction

To base management and conservation of natural resources on the knowledge of

the systems identifiable and definable dynamic and self sustaining landscape

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Summer School 2006 Krumme

18 FWU, Vol. 5, Participatory Watershed Management Plan

discrete units, would a great advantage over many other state of the art methods. It

would provide the planner and the manager with a definable element of the

landscape, whose internal interacting processes can concretely be studied. Impacts

of any activity on such a mini landscape element are easily identified thus making

such assessments as ecological risk assessment (ERA) more effective. We term

such a unit in the landscape or ecosystem an Ecological Functional Unit (EFU).

The author recommends that the EFU be treated as the smallest mapable landscape

functional unit. This way the EFU can serve as the basis for an integrated planning

and management of landscapes and the resources therein.

Definition of EFU

In his search to find out the functional components of a complex entity referred to

as a landscape, a German biologically oriented geographer, Carl TROLL in 1950,

coined up the term ecotope (NAVEH & LIEBERMAN 1984). He then went

ahead to hypothesize that a landscape is composed of landscape cells or tiles

which are homogeneous with regard to abiotic factors: physical and chemical

properties of a particular substrate such as porosity, pH, texture and mineral

contents. Such small cells are known as physiotopes. When colonised and

transformed by organisms, the physiotope site, via biotic and abiotic interactions, is

transformed into a mini holistic land unit characterized by homogeneity of at least

one ecological land attribute such as geological parent material, vegetation, soils,

water, climate etc. and non-excessive variations of the other attributes present

(NAVEH & LIEBERMAN 1984). An ecotope thus displays such micro-

ecosystemic functions as succession in a biological community, establishment of

special and temporal micro-climates, building up of niches, energy flow and

nutrient circulation.

When definable elements in a landscape are functionally linked together and

forming a unique pattern of spatial relationship, they build a cluster of landscape

elements forming a landscape unit with peculiar character and function that differs

from other units. We describe the connecting factors of different landscape

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elements as integrating factors. We define the landscape unit so formed as an

Ecological Functional Unit (EFU). The land attributes that are influencing the

interconnection and ecological integration of landscape elements are to a large

extent the land form and geology (which influences meso-scale hydrology,

particularly drainage patterns), local climate regime, or transport of abiotic or

biotic materials and energy etc. that take place in distinctive cut outs of the

landscape to be described as ecological process zones.

It is important to stress that the character and functionality of the ecological

functional unit is not a sum of the ecotopes composing it. The interactions between

the physical and biological factors of the individual ecotopes with each other and

with the new topography created through the integrating factor(s) do create a whole

new and unique dimension of characteristics that are unique to that particular EFU

and differs from those of the individual ecotopes or those of the neighbouring

EFUs. Different EFUs will differ in their structure (ecotope composition) and

functional processes (integrating factors).

The Importance of EFU for Development Planning

From the above explanations, it can be concluded that a particular ecotope in one

part of the landscape plays a completely different role from another ecotope (of the

same type) in another part of the same landscape, because of its interrelationships

with the surrounding landscape. It is therefore advisable not to base any judgments

of potential impact from any activity on the assessments of one particular ecotope

without establishing the linkages between that ecotope and others with which it is

connected. Usually an activity taking place on one ecotope has direct or indirect

impacts on the other ecotopes with which it forms the EFU. Likewise since the

functioning and quality of the EFU is determined by the cumulative quality and

cumulative functioning of individual ecotopes, performance and quality of the

entire EFU is likely to be affected by any activity on one or more ecotopes

composing it.

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The knowledge of the EFU in the landscape therefore becomes extremely

important in guiding the decisions for management, extents and impacts of

assessment and monitoring procedures among others. The clustering of functional

landscape units is therefore a more realistic means of understanding the ecosystems

than the use of their visual appearance and structural homogeneity, as is often the

case in traditional landscape planning approaches (see MARTINEZ-FALERO &

GONZALEZ-ALONSO 1995). Structural homogeneity is an aspect of a mere

human visual perspective.

In principle, the pattern of functional landscape units exists on every level of

landscape hierarchy, not only on the site level that is target of decisions of for

example management measures for the usage of water resources, vegetation or

geo-resources in a demarcated water catchment (sub-regional level). Landscape

ecology recognizes the existence of clusters of sites, ecosystems or landscapes at

local, regional or global scales. Deriving from our definition for the EFU, it may be

possible to argue that landscapes do not only have functional and structural order

but be also spatially structured and ordered in a hierarchy of functions at variouslevels.

To be successful, ecological planning must respond to the functional order of the

landscape and identify those landscape units that represent the functional clusters

at different scales (Figure 1). For the explained background this approach in

planning has an advantage of maintain ecosystem functioning and health, which

are ultimate goals of sustainable development, unlike most of the current

conservation and development planning approaches, which are oriented on static

goals of resource availability, accessibility of resources, species or structural

richness in the nature, and thus ignoring the functional processes necessary for

developing the patterns they want to conserve or be a basis for economicdevelopment (see also BALMFORD & MACE & GINSBERG 1998).The EFU

approach can be seen as a new attempt to provide the process that would contribute

to the solution of this problem and numerous other conflicts, when landscape

analysis is an ultimate necessity for land use planning. We refer to the planning

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process of recognizing the functional units at different regional landscape scales as

the ecological functional clustering.

Bioregions

In this light we see the so called bioregions (MILLER 1996, BRUNCKHORST

1995, 2000, AJATHI & KRUMME 2002, KRUMME & AJATHI 2006) as

functional clusters of ecosystems and broader landscape units interacting withhuman cultural subsystems. The most determining force in forming a bioregion is

thus the geomorphology as the main underlying driver for site conditions of water,

temperature or nutrients, in forming ecological gradients and at least a main natural

determinant for human settlement and culture. Thus the bioregion is a natural

comprehensive cluster of multiple ecological, socio-cultural and economic features

and the frame in which all these phenomena should interact in a sustainable

manner. The planning process for a sustainable development should thus have the

bioregion as its central management unit.

Water Catchment Areas

For the necessary downscaling and the provision of concrete action plans the

introduction of sub-regional management referring to water catchments appears as

a suitable and strategically coherent means. Water catchments that are naturally

characterised by its watersheds as functional entities could be integrated into such a

hierarchical approach to development planning as another level of ecological

functional clustering that is consistent with the principles explained earlier.

Conservation Areas

Another practise oriented level of planning can be the establishment of protected

areas for the background of conserving ecological processes with an ultimate

function for the regional ecological sustainability. In a bioregional contexttherefore, a protected area should be planned as a priority cluster of key ecological

functions. The protected areas serve as management units for the key processing

areas, which provide important and essential ecological services to the respective

bioregions and at the same time, serve as the ecological architecture of a

bioregion.

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ECOLOGICAL FUNCTIONAL CLUSTERS IN DIFFERENT PLANNING SCALES

Bioregion as comprehensive functional cluster of multiple ecological,

socio-cultural, and economic features

Water Catchment Areas (subregional) + X

EFU x n

Ecotopes

ECOLOGICAL FUNCTIONAL CLUSTERS IN DIFFERENT PLANNING SCALES

Bioregion as comprehensive functional cluster of multiple ecological,

socio-cultural, and economic features

Water Catchment Areas (subregional) + X

EFU x n

Ecotopes

Figure 1: An Association of Functional Clusters in Different Landscape Scales

The Procedure of Functional Landscape Analysis

Being a new idea, the EFU concept in landscape planning has no practical field

application experience as yet. This paper only provides a theoretical process for the

identification of the ecological functional units in the landscape. The author hopes

the application of these ideas in the future will produce concrete results to a

description of an innovative methodology for functional landscape analysis.

Delineation of EFU on the site level, or more generally different functional

landscape units in different scales, starts with the consideration of the factors that

are likely to determine process functioning and structure of the area targeted for

planning. Assessment of those factors could be done using both the inventories of

the ecological records accompanied by analysis of the maps, area photographs and

satellite derived information with the help of computer technologies such as GIS

(Geographical Information System) and simulation programmes.

A first impression of the factors composing the landscape is made through a

systematic classification of the important ecological drivers for landscape

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phenology and function. We classify those landscape factors in four groups

namely:

Limiting factors: These are the ecological factors that control the growth

and succession of a plant community and that lead to a gradual change in

the ecosystem. Examples are water (PAM: plant available moisture),

nutrients (PAN: plant available nutrients) or climatic limits for plant oranimal communities like minimum temperature or extreme heat in day

rhythmic or as seasonal recurring events.

Trigger factors: These are natural phenomena that usually trigger a sudden

major shift or change in the ecosystem. Examples in some ecosystems are

fire or flood and drought. Some of these phenomena, like fire, can also be

caused by human culture (HARRIS 1980 for Savannah ecosystems).

Conditioning factors: These are dominating factors in an ecosystem

setting, which play important roles in determining an ecosystem, but do not

limit its succession. Examples are water in a river or a lake or soil

characteristics like the high nutrient volcanic ashes of the Serengeti grass

plains in Tanzania.

Integrating factors: An integrating factor represents the connectivity of the

sub-systems of a landscape. Landscape patches, like seasonal ponds, small

woodland plots or swamps, can be connected by natural corridors and

pathways (e.g. through groundwater layers, linear pattern of trees and

bushes or a seasonal brook or river including their riparian vegetation) in-

between a surrounding landscape matrix like a Savannah of a grassy

phenology.

To understand the dynamics of functions of the landscape spatial elements and

over time scales, it is necessary to examine the factors of landscape carefully.

Especially the role played by the integrating factor is of crucial importance in the

functional analysis process. The integrating factor provides the frame on which the

corresponding (connected) elements (e.g. ecotopes) in the landscape synchronously

function, by determining the degree of connectivity between those ecotopes. The

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integrating factor can in its associated elements of an EFU also represent the

functions of limit to growth, trigger or general condition.

An Example on Water

Water is one of the determining factors in the development of a valley in a

landscape where seasonal flood events are occurring. These events form the

geomorphology of the valley through the erosive and abrasive force of the floodingwater and the materials transported in it. For most of the year in the centre of the

valley there is only a small stream, where water is the conditioning factor of an

aquatic ecotope. Connected to the stream are riparian ecotopes, which are

determined by plant available moisture (PAM) as a limiting factor and which is

provided by the stream. On higher flood plains of the valley water is only available

for a short period of the year and can here play the role of the trigger and limiting

factor for the vegetation growth period. Likewise it plays the role of a trigger for

multiple effects in the plant and animal community (e.g. reproduction behaviour)

during the flood period. All these ecotopes are depending on one integrating factor:

water. Interference in one of the ecotopes (e.g. the valley riparian ecotope) may haveserious destructive consequences for the equilibrium of the whole functional unit.

Given the above described landscape phenomena, the examination of functional

connections between different parts of the landscape is therefore a must if realistic

conclusions concerning the impacts of any activity in a landscape has to be drawn.

It is evident therefore that landscape analysis on the basis of single ecotopes is

likely to produce errors and incomplete information for planning purposes.

During the landscape analysis and delineation of the functional landscape units

process it is advisable to orientate on the following principles:

Do not focus on homogeneous structures in the landscape but on the

ecological processes determining and integrating these structures and the

inhabiting species.

Verify the effects any given landscape pattern would have on the landscape

functioning before adopting it as a basis for further action.

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Always consider the mechanism and sources of the ecological processes in

the landscape which determine other physical factors such the distribution

of water, temperature and nutrient.

From the background of the above EFU description, an ecological functional

clustering can be determined in five major steps (see also Figure 2):

Examination of the geographical distribution of water (which standsstrongly connected with the nutrient distribution), the main climate factors

(temperature, evapotranspiration, wind systems) and the soil parent material

(geo-resources) in the planning area.

Identification of the processes which drive those distributions. The landform

(geomorphology) thus plays a key role, because it determines the directions

and pathways of flows through slope aspect and elevation (e.g. drainage

characteristics) (BELL 1998). These flows can occur either in a simple

linear connection of source and storage (of e.g. nutrient or water) or as a

more complicated cycle (e.g. temperature and local wind systems).

By integrating the above two steps, it is possible to delineate zones in which

the processes and flows are taking place. According to BELL (1998), these

zones are called Pronounced Processing Zones of the landscape (PPZ)

which represent the borderlines for functional landscape units.

With regard to a time scale sometimes the dynamic distribution or

availability of abiotic factors like water or temperature in an area triggers

periodic cyclic movements (migrations) of biodiversity between different

parts of a landscape. Therefore animal migrations can be an appropriate

indicator of those driving processes and simplify the delineation of

processing zones.

In the case of a site based planning, the analysis up to this point is

incomplete. This is because we do not yet know exactly the elements

composing the ecological functional unit. The distribution of soil-

vegetation-systems of the planning area should therefore be examined to

define the extent of the ecotopes. Correlating this with the afore mentioned

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energy flows, we are finally able to characterize an EFU. This aspect is

logical because the soil and vegetation pattern are a direct result of the afore

analysed abiotic processes.

The sequential order of these steps as shown in (Figure 2) is important. It would be

an impediment to begin a functional landscape analysis with the examination of

soil or vegetation, because this would be obstructing the basic processesresponsible for those patterns of vegetation and soil formation. It is absolutely

necessary first to focus on the ecological drivers shaping the larger landscape

structure and only apply that information at a later time during the down scaling to

an ecotope level.

BASIC

GEO MAP

GEO MAP

PHYSIOTOPEMAP

ECOTOPEMAP

PPZ

RECOGNITION

EFU

DEFINITION

water climat

eeee

eeee

eeee

eeee

geology

landform

soil

vegetation

ECOLOGICAL FUNCTIONAL LANDSCAPE ANALYSIS (SITE LEVEL)

BASIC

GEO MAP

GEO MAP

PHYSIOTOPEMAP

ECOTOPEMAP

PPZ

RECOGNITION

EFU

DEFINITION

water climat

eeee

eeee

eeee

eeee

geology

landform

soil

vegetation

ECOLOGICAL FUNCTIONAL LANDSCAPE ANALYSIS (SITE LEVEL)

Figure 2: Ecological Functional Landscape Analysis on the site level

Conclusions

It was shown that rather to refer to homogeneous structures in landscape mapping,

it has a great advantage to assess process zones that consist of several different but

ecologically connected subsystems and are forming a heterogeneous functional

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cluster. If this cluster is the basis for the evaluation of the geographical situation,

suitability and intensity of the human interference into the natural resource base of

a special area, the hereby presented theoretical approach provides the prerequisite

to realistically measure the impact of these actions for the long term sustainability

of the broader landscape system. Doing so natural resource use in planning areas

goes a step forward to the goal of the long term stability of human used natural

systems.

Furthermore the described idea offers a framework for a hierarchical system of

land use on different spatial levels according to the naturally given functional order

of landscape ecology and with this a valuable contribution to sustainable

development planning.

References

AJATHI, H.M. & KRUMME, K. (2002):Ecosystem based Conservation Strategy forProtected Areas in Savannas - with special Reference to East Africa (Joint

M.Sc. Thesis). University of Duisburg-Essen, Miless Electronic LibraryEssen: http://miless.uni-duisburg-essen.de/servlets/DocumentServlet?id=11932

BALMFORD A., MACE, G.M. & GINSBERG J. (1998): Conservation in a ChangingWorld. Cambridge University Press, Cambridge.

BELL, S. (1998):Landscape : patterns, perception, process. London.

BRUNCKHORST, D.J. (1995): Sustaining Nature and Society - A BioregionalApproach. In: Inhabit No. 3, pp 5-9.

BRUNCKHORST, D.J. (2000):Bioregional Planning: Resource Management Beyondthe New Millennium. Harwood Academic Publishers: Sydney, Australia.

KRUMME, K. & AJATHI, H.M. (2006):Learning Bioregions Concrete Visions for

Sustainability, First German Conference on Sustainability Research,TuTech, 24th

of March 2006, Hamburg.

MARTINEZ-FALERO, E. & GONZALEZ-ALONZO, S. (1995): Quantitative Techniquesin Landscape Planning. Lewis Publishers, CRC Press, Florida .

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MILLER, K. (1996):Balancing the Scales. Guidelines for Increasing Biodiversitys

Chances through Bio-Regional Management. World ResourcesManagement. Washington, D.C., U.S.A.

NAVEH & LIEBERMANN (1984):Landscape Ecology. Cambridge University Press,

Cambridge.

SMITH, R.D. & MALTIBY, E. (2001): Using the Ecosystem Approach to implement

the CBD (Global Synthesis Report). University of London, London.

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