Biodiversity tipping points and biodiversity -dependent socio -ecological systems

Biodiversity tipping points and

biodiversity-dependent socio-ecological systems

Pathways for human adaptation?

Prof. Patricia Howard, University of Kent at Canterbury and Wageningen University, the Netherlands ([email protected])Dr. Thomas Thornton, Environmental Change Institute, Oxford

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):

o Mobility (e.g. habitat tracking, migration)o Exchange (e.g. biological trade corridors)o Rationing (e.g. through ritual redistribution)o Pooling (e.g. of decimated herds)o Diversification (e.g. camel pastoralists begin to

fish)o Intensification (e.g. using greater labour inputs)o Innovation (e.g. changing technology)o Conservation (e.g. creating ecological niches)o Revitalization (e.g. regenerating

conservation/management values, limits to accumulation)

Sahrawi nomads’ adaptation (Volpato 2012)

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