Analyzing resilience in dryland agro-ecosystems

A case study of the Makanya catchment in Tanzania

Elin Enfors

Natural Resources Management

Department of Systems Ecology

Stockholm University

Based on manuscript by Enfors and Gordon (2006), submitted to World Development

• Presenting a conceptual framework for analyzing resilience and conceptualizing alternative trajectories of developmentin smallholder farming systems

• Applying this framework on the Makanya catchment in Tanzania

A combination of qualitative and quantitative methods used:

• Interviews with local farmers, extensionists and authorities about agro-ecological changes and underlying driving forces

• aerial photo/satellite image interpretations of land cover change

• analysis of rainfall dynamics

Why focus on dryland agro-ecosystems?

• 250 million people in SSA: poverty, population growth, and malnourishment

• Small-scale rainfed farming main income source, but productivity low

• People depend on ecosystem services such as fodder for livestock,firewood and construction materials to cover basic needs

• Climatic constraints and poor soils limit the agro-ecological productivity and make drylands inherently dynamic and vulnerable

• Land degradation reduce both productivity and capacity to cope with change

The resilience concept

Definition: the capacity of a social-ecological system to absorb changes, and to reorganize after and adapt to them, so that essential functions are not lost

• Social-ecological systems can have multiple stability domains, characterized by different functions and feed-backs

• Low resilience increases the probability for shifts between these

• Most systems are robust over a range of conditions but respond strongly when key variables approached certain thresholds

The resilience concept applied

The main function of agro-ecosystems is to generate food and other ecosystem services needed by the population

Two alternative states envisioned for this system: one desirable where this capacity is up-held over time, one degraded where is is not

We propose that the “soil water index” and the “ecosystem insurance capacity” are two of the key variables in this system

Soil water index - amount water available per capita for food production

• Rainfall and run-on

• Probability of actually receiving this due to dry-spells etc.

• Soil properties affecting plant available water and plant productivity response to this water

Ecosystem insurance capacity - capacity of the surrounding landscape to provide ecosystem services that could buffer yield variations

• Availability of such ecosystem services (timber products, wild life etc.)

• Capacity of the resource base generating these to recover after periods of stress

The conceptual framework

The Makanya catchment

The Colonial period - 1961

The Development of independent Tanzania 1961-2985

The economic liberalization period 1985-

Socio-political structure

• Low population that live from subsistence farming• The colonials rule through local chiefs• Imposed cash crop production

• Population growth, improved health and education• Socialism, self-reliance and ujamaa national goals• Villagization

• Economic crisis leads to reforms and SAP• Multi-party system adopted• NGOs important actors in rural development• Participation on the agenda

Natural resource management

• Colonial laws to protect land, water and forests exist parallel to local institutions for resource access/control• Local chiefs enforce these rules and laws

• Replacement of local chiefs leads to weaker protection of NR• Farming and livestock keeping more permanent• By-laws created to protect the environment

• By-laws for environmental protection inefficient• Far reaching policy changes make alternative forms of NRM possible

Local perceptions of agro-ecological conditions

• Natural resources used in daily life readily available• More reliable rainfall• Only a small portion of the land used for farming

• Expansion of agr. land, farmers cultivate both seasons• Protected areas encroached upon• Decreasing forest / bush land cover• Disappearance of wildlife• Drier conditions

• Lack of farming land in spite of expansion, low soil fertility• Illegal logging - large scale problem• Natural resources used in daily life increasingly difficult to find• Low rainfall and pop. growth seen as reasons behind this change

The narratives on agro-ecological change and land cover change analysis largely support each other

Analysis of rain data

High variability, no significant changes

Significant increase, p=0.024

Summary

• Over the past 50 years the landscape in the catchment has undergone considerable changes: reduction in bush land and expansion of farm land, loss of ecosystem services other than food

• At the same time the frequency of dry-spells has increased significantly and the population in Same district is estimated to have increased with more than 200 %

Applying the resilience framework on this case

a) Population increase outgrows management of farming land -> decline in SWI, accelerated by increasing dry-spell frequency

b) Low SWI -> increased dependency on ecosystem insurance capacity. Institutions for access and control of NR collapse -> the system moves to the degraded state

c) Today: a system where production of food and other ecosystem services is not upheld over time

A window of opportunity for change seems to be opening:

• Awareness of the problem

• Practical solutions available - soil and water system innovations: water harvesting, conservation tillage etc.

• Policy changes the last 10 years have made local initiatives for NRM possible

• New local institutions are being built

Potential for reversing a negative trend

Thanks for listening!