Biodiversity tipping points andbiodiversity-dependent socio-ecological systems Prof. Patricia Howard, University of Kent at Canterbury and Wageningen University, the Netherlands (P.firstname.lastname@example.org) Dr. Thomas Thornton, Environmental Change Institute, Oxford Pathways for human adaptation?
Overview: complex, novel topic • Nature of biodiversity tipping points (BTP) per se and at local scale? • Nature of highly biodiversity-dependent societies (HBDS)? • Consequences of BTP for HBDS and adaptation of HBDS given BTP? • Planetary consequences?
Why biodiversity change? • Biodiversity loss is a major driver of global environmental change (Hooper et. al. 2012) and it is probable that there is a mass extinction underway • Environmental change impacts humans principally through changes in flora and fauna • Biodiversity change has many other drivers besides climate change
What is biodiversity change? • Species richness (number of species) • Species abundance (how common, or rare) • Species phenology, range (timing of budburst, leaf fall, reproduction; geographic dispersion (habitat) and mobility • Can reorganise entire ecosystems - including tipping • Drivers: Land use change, habitat fragmentation, invasive species, pollution, pathogens, degradation, over-harvesting, climate change
What are ‘biodiversity tipping points’? • ‘Tipping point’ concept only recently linked to biodiversity but not yet systematically explored (GBO4) • Majority of ecosystem tipping points may be related to biodiversity (diversity, abundance, or functionally important species) • Dynamics: climate-vegetation feedbacks, transitions in semi-arid vegetation, species extinctions in fragmented landscapes, etc. (Scheffer 2009, Critical Transitions).
Possible regional biodiversity tipping points (Leadley et al. 2010) • Amazon forest dieback • African Sahel desertification • Island ecosystems collapse from invasives • Invasion of tundra by boreal forests • Coastal terrestrial systems and sea-level rise • Marine fisheries • Tropical coral reefs
Example: Amazon dieback • Forest dieback – ‘flipping’ to savannah and semi-desert, uneven effects across the region • Climate-vegetation feedbacks – climate change + deforestation = drying + fires • ‘Important’ changes by 2025, ‘flip’ by 2050?
Local biodiversity tipping points Can occur through, e.g. • Loss of specific species (framework species, ecological engineers); • Loss of trophic levels (e.g. large predators); • Loss of communities (e.g. through pollution, disease)(Dobson et. al. 2006)
Local-global synergies • Global state shifts: global forcings or many smaller-scale events originating in local systems? • Past global state shifts all related to global scale forcings that modified oceans, atmosphere, and climate • Known that ‘local-scale state changes…trigger critical transitions over larger regions.’ • If enough systems transform, the rest may change rapidly, ‘especially because emergent, larger-scale forcings…multiply and interact to exacerbate local forcings’ (Barnosky et. al. 2012).
Humans are keystone species across 77% of terrestrial ice-free area (Ellis & Ramankutty 2008)
‘Human societies have been built on biodiversity’ (Díaz et. al. 2006 • The human ‘project’ is to alter the environment – humans organise socially to alter the environment to meet socially-defined needs • Human-nature co-evolution: humans are keystone species and environments shape culture • Humans create tipping points – e.g. urbanisation, hydrological engineering, deforestation/intensive agriculture • The type/degree of environmental transformation depends fundamentally on the ‘rules’ of the mode of production/subsistence - not all societies degrade the environment or over-exploit resources
Today’s highly biodiversity-dependent and highly adaptive societies • of the world’s population…40% subsists to a large degree from agriculture, which occupies 40% of terrestrial ice-free area • 90% of farmers cultivate 2 ha. or less; at least 50% is ‘traditional’ - usually biodiversity-rich polycultures • 250 million live largely from forests, and 60 million indigenous people live exclusively from forests • 50 million depend on small-scale fisheries • 1 billion regularly consume wild food • 1.3 billion live from ‘environmentally fragile’ lands where environmental disturbances and disequilibria rule
Different social formations/environmental relations/resilience • Cultural evolution (e.g. Richarson & Boyd 2005) – has allowed humans to adapt to every type of environment on Earth • Institutions (means of production & exchange, knowledge, technology and innovation) have evolved in part in function of environmental disequilbria and disturbance • Often are low or no external input, biodiverse, knowledge-intensive, with social rules and religious beliefs that regulate resource access and use • Resilience based on institutionalised adaptive capacity, but this is generally ignored by outsiders
Humans are highly adaptive to environmental change Historically a range of pathways to adapt to biodiversity and other environmental change (Thornton and Manasfi 2010): • Mobility (e.g. habitat tracking, migration) • Exchange (e.g. biological trade corridors) • Rationing (e.g. through ritual redistribution) • Pooling (e.g. of decimated herds) • Diversification (e.g. camel pastoralists begin to fish) • Intensification (e.g. using greater labour inputs) • Innovation (e.g. changing technology) • Conservation (e.g. creating ecological niches) • Revitalization (e.g. regenerating conservation/management values, limits to accumulation)
Types of biological outcomes that may lead to SES tipping points • Loss of communities – e.g. forest to savannah as in Amazon dieback, deforestation • Loss (or loss of productivity) of cultural keystone species (camels, eagles, herring, sago palm,etc.) • Loss (or loss of productivity) of other functionally non-redundant species (culturally, economically, ecologically) or trophic levels (e.g. large fish) • Gain of negative species (e.g. elephants, poisonous plants, disease-bearing organisms)
Vulnerability to biodiversity change • Exposure and physical susceptibility (e.g. degree of dependence on species and services that species provide – greater in arid areas, islands, Arctic, coasts) • Breakdown of institutional resilience (loss of knowledge and skills, institutional means of sharing and reconstituting resource base) • Social, economic, and ecological fragilities presented by modern institutions and power relations • Loss of languages and cultures – faster than the current rate of species loss
Modern limits to adaptation or, moving toward collapse? • Prior occupation and other restrictions on movements: borders, nationalism, prior access rights to land, forests, etc., prohibit e.g. habitat tracking, migration • Profit criteria determine resource allocation and use (e.g. land grabs for biofuels or food production) • Power relations (economic but also political) determine who is able to do what with what; who pays costs and who reaps benefits • Limits on collective action – e.g. on what the State and other public institutions can do vis a vis private interests • Knowledge – scientific knowledge is imprecise; local knowledge may be fragile or become inappropriate • Probability of maladaptation (dependence on state and corporate dividends; outmigration with loss of identity and connections to land/community) • Conflict and overspill, upscaling of tipping points
Ruminations • Crossing biodiversity tipping points is nearly inevitable; • We need lots of alternatives for adaptation and generating new stable states - a) institutional arrangements, b) economic relations, c) human-nature relations, and d) knowledge and information, and these must be locally adapted; • Thus, we need evolved planetary cultural resilience in the form of biocultural diversity but we are losing it more rapidly than we are losing species; • We know almost nothing about things that we need to know a great deal about, and lack the wisdom to know it