Objectives, motivations and strategies of ecological restoration James Aronson (CEFE / CNRS, Montpellier, France) CENTRE D ECOLOGIE FONCTIONNELLE & EVOLUTIVE CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
Definición (Soc. Ecological Restoration International, 2002 www.ser.org/primer) Procesos de ayudar a la autoreparación de un ecosistema que ha sido degradado, dañado o destruido. (Mediterranean Socio-ecosystems
La restauration écologique : le processus d assister l auto-regénération des écosystèmes qui ont été dégradés, endommagés ou détruits. (www.ser.org/primer, 2002)
Ecological restoration : the process of assisting the recovery of ecosystems that have been degraded, damaged or destroyed. (www.ser.org/primer, 2002) Rehabilitation focuses on processes, functions; Restoration aims at restoring content (biodiversity) as well as processes.
L Homme peut-il refaire ce qu il a défait? Quelles références? Quels niveaux écologiques parcelle (m²), rive (km), bassin versant ou paysage (km²), écoregion, biosphère,.?
Les piliers I. Concepts, objectifs, modèles II. Outils de travail biologique et mécanique III. Méthodes d évaluation et de suivi de systèmes entiers et ouverts IV. Intégration, Cooperation,
WHY Restore? Approach-A: Recover a certain authenticity historical or natural. Drivers basically spiritual, cultural, aesthetic, pacific, etc.
(Source: Hobbs & Norton, 1996) Level of complexity/function Degraded state Desired state Continued decline Alternative states Subsequent decline Stays the same Time
Level of complexity (Natural Capital Value) NATURAL CAPITAL Original ecosystem Degraded state? After Hobbs & Norton (1996)? Rehabilitation Most biologically complex Restoration Rehabilitation Desired trajectory Subsequent Decline (failure) Continued decline Alternative states trajectories Stays the same Time (Aronson & Milton, in press)
Approach WHY Restore?? B: Preserve or even augment renewable natural capital, i.e., goods and services of natural and socio-ecological systems on which we all depend. >> Drivers pragmatic & idealistic, varying among cultures.
economic social Restoration of degraded ecosystems ecologic cultural (Jackson et al., 1995; Higgs, 1997)
RESTORING NATURAL CAPITAL: AN ECOLOGY/ECONOMICS CONSILIENCE PLATFORM J. Aronson, J. Blignaut, A. Clewell and R. Costanza
Ecosystems (incl. biodiv.) can also be called Natural Capital. Natural goods and services represent the interest (= flows) earned on Natural Capital (= stock).
NORTH Exporters of technology and manufactured goods. Exporters of economic models Colonizers of southern lands; old rich millions. High per-capita consumption; generators of greenhouse gas. Theory-driven research; scientific knowledge. Biodiversity poor. ECONOMIC DIVIDE Exporters of raw materials. Importers of economic development models Formerly colonized; young poor billions. Low per-capital consumption; recipients of climate change. Traditional knowledge and action-driven research. Biodiversity rich. SOUTH Aronson & Milton, in prep; modified from Kates et al. (2001).
Les piliers I. Concepts, objectifs, modèles II. Outils de travail biologique et mécanique III. Méthodes d évaluation et de suivi de systèmes entiers et ouverts IV. Intégration, Cooperation,
(Harris & Van Diggelen, 2005; Whisenant 1999) Abiotic Biotic Fullyfunctional Requires Physical Modification Requires Biological Modification Requires Improved Management 1 Ecosystem Attribute 4 3 2 6 5 Reclamation Restoration Non-functional Degraded ECOSYSTEM STATE Intact
* Plantations multi-strate vs. mono-strate * Espèces «natives» vs. espèces introduites
Landscape perspective LAMB, TONGWAY, LUDWIG,.
RESTORATION Active management Intact (original) ecosystem Disturbance & transformation Emerging alternative ecosystem Prolonged and/or intensive disturbance & transformation Simplified ecosystem Local spp. Alien spp. Reintroduction of plants Reactivation of processes SETTING GOALS Future dynamics?? Value of ecosystem goods & services Slowly emerging ecosystem of some sort Degraded condition and loss of function Do nothing REHABILITATION LAND USE CHANGE (REALLOCATION) Transformed ecosystem Desertified system??? Cost of RNC Abandonment Aronson & Milton, in press
Source: Blondel & Aronson, 1999 INCREASING BIODIVERSITY INCREASING IMPORTANCE OF HUMAN DETERMINANTS
Some successional pathways in eastern Spain Dashed lines represent slow or rare pathways. (Vallejo, Aronson, Pausas & Cortina, 2005). 120 100 Oak forest Biomass (Mg ha -1 ) 80 60 40 Pine woodland Ulex shrubland Garrigue 20 Sward 0 0 10 20 30 Species richness (100 m 2 )
Emerging ecosystems? Emerging ecosystems? "Wild" Intensive agriculture Degradation Invasion Abandonment R. Hobbs et al. (in review)
VALUE ($) TIME (Years) CONSUMPTION BIOL. INVASIONS TOURISM WARM ING V o SCIENCE (Figueroa, Aronson, Milton, in review) t 1 A B C??? RECREATION EXTRACTION CULTURE EM ERGING ECOSYSTEM POLLUTION POLITICS POPULATION SURPRISES AGRICULTURE WASTE t o BUILDING
Références.historiques et autres A fundamental aspect of ecosystem restoration is learning how to discover the past and bring it forward into the present. Egan & Howell (2001) The Historical Ecology Handbook: A Guide for Restorationists
Brusquet Valley, southern France, before and after a RTM project (Restauration de Terres de Montagne (1877) and a century later (1995) (photos: D. Vallauri WWF-France)
? Which reference system?
Four types of ecological references (White & Walker 1997) Different place, same time (refuges) Same time, different time (archeology) Different place, different time Same place, same time (auto référence)
Reference dynamics: Reconstructing ecological processes to restore natural variability Don Falk Laboratory of Tree-Ring Research University of Arizona Tucson, Arizona, USA
(Source: Aronson & Van Andel, in press)?????? Natural capital Reference C Reference B Reference A A B C TIME Initiation of restoration
Biosphere Protection Sustainable use Natural capital persistence Restoration Milton and Aronson in review. Restoring Natural Capital: Views from the South. Island Press.