St udy sit es Clear - cut t ing (above) and t hinning (t o t he r ight ) in Aleppo pine f or est s sout her n Tunisian ar id st eppes Menzel Habib Obser vat or y (ROSELT/ OSS) Concept ual f r amewor k The 5- step method (McI nt yre & Lavorel 2001) Step 1. Identifying species response groups Examine how species composition among hemicryptophytes and chamaephytes changed in response to disturbances (tested by Canonical Correspondence Analysis) Step 2. Identifying emergent groups Search for correlation patterns among species’ attributes within plant communities (Canonical Analysis) Step 3. Identifying life trait responses Analyze, for each attribute, the variation in its relative abundance in the plant community, with respect to level of disturbances (General Linear Model analysis) Step 4. Identifying syndromes Examine the degree to which attributes-based emergent groups (step 2) are related to the sets of attributes that were significantly associated with disturbances (step 3) Step 5. Functional types Identify functional response groups summarizing results of steps 3 and 4 and relating them to individual taxa (step 1) ; examine how the attribute response groups match actual species responses PLANT FUNCTI ONAL TYPES: A PROMI SI NG TOOL FOR THE RESTORATI ON OF DEGRADED LAND PLANT FUNCTI ONAL TYPES: A PROMI SI NG TOOL FOR THE RESTORATI ON OF DEGRADED LAND Hélène GONDARD 1* , Sandrine JAUFFRET 2 , Sandra LAVOREL 1 , James ARONSON 1 1 Centre d’Ecologie Fonctionnelle et Evolutive, CNRS UPR 9056, 1919 route de Mende, F- 34293 Montpellier Cedex 5, France 2 Pôle I nst it ut de Recherche pour le Développement , Maison de la t élédét ect ion, 500 rue Jean François Bret on, 34093 Mont pellier cedex 5, France E- mail : gondar d@cef e. cnr s- mop. f r , s. j auf f r et @voila. f r , lavor el@cef e. cnr s- mop. f r , ar onson@cef e. cnr s- mop. f r CENTRE D’ECOLOGIE FONCTIONNELLE & EVOLUTIVE I nt r oduct ion Throughout the Mediterranean region human activities often constitute major disturbances to vegetation dynamics which vary in frequency, intensity and spatial distribution. To minimize or reduce loss of biodiversity, it is necessary to better understand and predict the behaviour of various response groups within plant communities. The characterization of community responses to any given disturbance, in terms of functional groups, appears to be a promising tool for this purpose. Plant response groups can be defined as containing species which respond in a similar fashion to selected environmental factors, as a result of their shared biological traits (Lavorel et al. 1997). I nt r oduct ion Throughout the Mediterranean region human activities often constitute major disturbances to vegetation dynamics which vary in frequency, intensity and spatial distribution. To minimize or reduce loss of biodiversity, it is necessary to better understand and predict the behaviour of various response groups within plant communities. The characterization of community responses to any given disturbance, in terms of functional groups, appears to be a promising tool for this purpose. Plant response groups can be defined as containing species which respond in a similar fashion to selected environmental factors, as a result of their shared biological traits (Lavorel et al. 1997). Obj ect ive The main objective was to evaluate the effects of a severe disturbance - logging or over-grazing - on plant species diversity, 1) in natural Aleppo pine (Pinus halepensis) forests of southern France and 2) in steppic ecosystems of southern Tunisia. A five - step method (McIntyre & Lavorel 2001) was used to identify functional response groups. Obj ect ive The main objective was to evaluate the effects of a severe disturbance - logging or over-grazing - on plant species diversity, 1) in natural Aleppo pine (Pinus halepensis) forests of southern France and 2) in steppic ecosystems of southern Tunisia. A five - step method (McIntyre & Lavorel 2001) was used to identify functional response groups. Ref er ences Diaz S., Cabido M., Zak M., Martínez Carretero E., Araníbar J. 1999. Plant functional traits, ecosystem structure, and land-use history along a climatic gradient in central-western Argentina. Journal of Vegetation Science, 10: 651-660. Garnier E., Shipley B., Roumet C., Laurent G. 2001a. A standardized protocol for the determination of specific leaf area and lead dry matter content. Functional Ecology, 15: 688-695. Garnier E., Laurent G., Bellmann A., Debain S., Berthelier P., Ducout B., Roumet C., Navas M.L. 2001b. Consistency of species ranking based on functional leaf traits. New Phytologist, 152: 69-83. Lavorel S., McIntyre S., Landsberg J., Forbes T.D.A. 1997. Plant functional classification: from general groups to specific groups based on response to disturbance. Tree, 12 (12): 474-478. McIntyre S., Lavorel S. 2001. Livestock grazing in sub-tropical pastures: steps in the analysis of attribute response and plant functional types. Journal of Ecology, 89 (2): 209-226. Ref er ences Diaz S., Cabido M., Zak M., Martínez Carretero E., Araníbar J. 1999. Plant functional traits, ecosystem structure, and land-use history along a climatic gradient in central-western Argentina. Journal of Vegetation Science, 10: 651-660. Garnier E., Shipley B., Roumet C., Laurent G. 2001a. A standardized protocol for the determination of specific leaf area and lead dry matter content. Functional Ecology, 15: 688-695. Garnier E., Laurent G., Bellmann A., Debain S., Berthelier P., Ducout B., Roumet C., Navas M.L. 2001b. Consistency of species ranking based on functional leaf traits. New Phytologist, 152: 69-83. Lavorel S., McIntyre S., Landsberg J., Forbes T.D.A. 1997. Plant functional classification: from general groups to specific groups based on response to disturbance. Tree, 12 (12): 474-478. McIntyre S., Lavorel S. 2001. Livestock grazing in sub-tropical pastures: steps in the analysis of attribute response and plant functional types. Journal of Ecology, 89 (2): 209-226. Conclusions These two studies can be useful to improve management strategies for the conservation and/or restoration of biodiversity and ecosystem services in the study areas and ecologically similar areas. Plant functional types are a good tool for diagnosis of disturbance processes and elaboration of long-term strategies in ecosystem management and ecological restoration projects. To further this line of research will require measuring relevant plant traits in situ, in communities, using standardized measurement procedures (Diaz et al. 1999; Garnier et al. 2001a and 2001b). Conclusions These two studies can be useful to improve management strategies for the conservation and/or restoration of biodiversity and ecosystem services in the study areas and ecologically similar areas. Plant functional types are a good tool for diagnosis of disturbance processes and elaboration of long-term strategies in ecosystem management and ecological restoration projects. To further this line of research will require measuring relevant plant traits in situ, in communities, using standardized measurement procedures (Diaz et al. 1999; Garnier et al. 2001a and 2001b). Lif e t rait s st udied accor ding t o available dat a in f loras and ot her lit er at ur e (logging- LO; over - gr azing- OG) Morphological LO OG Life history LO OG Reproduction LO OG Leaf structure Graminoid, malacophyllous, sclerophyllous or semi-succulent U U Nutritional mode Oligotrophic or eutrophic U Dispersal mode Wind, animal, other U U Leaf pubescence With or without hairs U Light tolerance Heliophyllous or shade tolerant U Regeneration mode Sexual or sexual + vegetative reproduction U U Plant height classes U U Flowering period Winter, spring, summer or year-round U Palatability U Sandy to loamy soils with thick gypsum crust when degraded Substrate limestone (m: ave. min. temp. of coldest month ; M: ave. min. temp. of hottest month) 14 (m = 1, M = 30) 800-900 200-300 Aleppo pine forests in southern France (logging) 20 (m = 6, M = 33) Mean annual temperature (°C) 150-200 Mean annual rainfall (mm) 45-100 Altitude (m) Steppic ecosystems in southern Tunisia (over- grazing) Variables Result s summar ized in dynamical st at e and t r ansit ion models State 1 Aleppo pine forest Co-dominance of hemicryptophytes and phanerophytes; shade tolerance & animal-dispersed seeds common State 2 Canopy reduction & thinning Increased diversity of hemicryptophytes, chamaephytes & phanerophytes State 3 Canopy removal Increased diversity of hemicryptophytes & therophytes; heliophylly common & wind or animal-dispersed seeds State 4 New management techniques Plant new tree species in mixed or pure stands Aleppo pine f or est , sout her n Fr ance St eppic ecosyst ems, sout her n T unisia State 1 Good Co-dominance of palatable chamaephytes and of perennial grasses (C 3 + C 4 ) High perennial plant cover State 2 Medium Dominance of palatable chamaephytes and of perennial grasses C 3 in protected habitats Great number of therophytes Medium perennial plant cover State 5 Degraded Dominance of unpalatable chamaephytes Great number of therophytes Medium to high perennial plant cover State 3 Steppe clearing and soil cultivation for cereal cropping State 4 Degraded to Very degraded Low or no perennial plant cover Great number of therophytes Eroded to bare soils Degradation Restoration Rehabilitation Reallocation