Presentation made at the Conference on ‘Cascade Ecology & Management – 2021’ 17-18 September, 2021 Organized by the Faculty of Agriculture, Peradeniya, Sri Lanka. The presentation introduced a new definition for tank cascade ecology

1. LESSONS LEARNT FROM DEVELOPMENT PROJECTS TO RESTORE TANK CASCADES
Dr. P.B. Dharmasena, Team Leader, Healthy landscapes Project, Ministry of
Environment:
Conference on ‘Cascade Ecology & Management
– 2021’
17-18 September, 2021
Organized by the Faculty of Agriculture,
Peradeniya, Sri Lanka

2. Definition of the Tank Cascade
Hydrology based definition
• A „cascade‟ is a connected series of tanks organized within a micro-catchment (meso catchment)
of the dry zone landscape, storing, conveying and utilizing water from an ephemeral rivulet‟. –
Madduma Bandara, 1985
Ecology based definition
• Tank cascade is an ecosystem, where water
and land resources are organized within the
micro-catchments of the dry zone landscape,
providing basic needs to human, floral and
faunal communities through water, soil, air
and vegetation with human intervention on
sustainable basis‟. – Dharmasena, 2017

8. Rural verses to forecast weather
ඳු
Can somebody recite the poems for me ?

9. Cascade Ecology
• Ecology is the study of the relationships between
living organisms, including humans, and their
physical environment.
• Cascade ecology does not confine to the cascade
boundary.
• Ecological influence spreads radially.
• Studies should be extended to outside areas of the
cascade
• Influence is of multifaceted (social, ecological)
• Cascade ecology knowledge is still like a just born
child
Ecological nuclei

10. Suggested Definition for
Tank Cascade Ecology
Tank Cascade Ecology is the study of the interactive
relationships between living organisms (flora and
fauna), including humans, and their physical
environment (soil, water and geo-morphology) within
the cascade boundary as well as its surrounding area of
influence.
Area of influence depends on various factors such as types of organism,
human intervention, biodiversity richness, surrounding environment etc.

11. Project - Mainstreaming agro-biodiversity conservation and use in Sri Lankan
agro-ecosystems for livelihoods and adaptation to climate change‟
• Project Period: 2012 – 2017
• Donor Agency: UNEP/GEF- Cycle IV Grant
• International Executing Agency: Bioversity International
• National Executing Agency: Ministry of Environment
• National Project Implementation Agency: DOA
• Project Objective: “to ensure that agro-biodiversity in Sri Lanka is optimally conserved and
used to meet the challenges of climate change and improve rural livelihoods”
• Project Sites:
• Low Country Dry Zone Village Tank System – Giribawa – Gampola tank cascade system
• Mid Country Intermediate Zone – Udukumbura Kandyan Home Garden System
• Low Country Wet Zone – Jamburaliya Peri Urban Agriculture (Ovita) System
This was the first project on Tank cascade system by the MoE

12. Lessons from the Agro-Biodiversity Project:
• People are not interested as they do not get immediate benefit;
• Some community leaders are politically motivated;
• People are discouraged on agriculture - poor recognition, low profitability,
environmental and climatic uncertainties and sudden changes in market (internal
migration from rural to urban areas, then labour shortage)
• Knowledge gap – confusion (traditional knowledge vs. modern knowledge on
agriculture)
• Soil nutrition imbalances and soil fertility reduction in agricultural land, due to
continuous farming practices.
• High cost of production in agriculture
• Value reduction of local animal genetic resources for agriculture development and
food and nutrition security
• Reduction of livestock diversity
• Isolation of climate change adaptations from other adaptations
• Some people are not currently practicing traditional knowledge

13. • Healthy Landscape Project planning was thought of under
such circumstances.
• The ancient tank cascade System – Can it be a solution to
address
• Climate change issues?
• Human health problems?
• Landscape sustainability?
• Biodiversity deterioration?
• Food system shift ?
• Water pollution?
What is this ancient Cascade system?
Ancient
Water
Tanks

14. Project: Healthy Landscapes: Managing agricultural landscapes in
socio-ecologically sensitive areas to promote food security, well-being
and ecosystem health
• Project Objective: Mainstreaming biodiversity using an integrated
land management approach to ensure, development, health and
environmental co-benefits
• Project Components:
1. Implementation of biodiversity activities to improve sustainable landscape
management;
2. Strengthening institutions, policies and integrated landscape planning;
3. Partnerships, awareness raising and capacity building to enhance ecosystem
services and eco-health outcomes
4. Knowledge, Information Management and Monitoring and evaluation

15. Project Component 1:
Implementation of biodiversity based options that improve sustainable
landscape management in socio-ecological sensitive areas;
1.1 Socio-ecological and biophysical system properties mapped and defined in 2
Project landscapes;
1.2 Community familiarization on VTCS restoration and agro-ecological and
sustainable land management strategies and practices;
1.3 Physical and ecological components of selected VTCSs restored as pilot models;
1.4 Biodiversity-based agro-ecological and sustainable integrated land management
practices implemented in the two selected VTCS pilot schemes;
1.5 Goods, services and functions of VTCS ecosystems identified and
mainstreamed.
Baseline study survey was carried out to establish the benchmark of the Socio-
ecological and biophysical status of the project sites with GIS mapping

16. Project Component 2:
Strengthened institutions, policies and integrated landscape planning of Village
Tank Cascade Systems (VTCSs) in socio-ecological sensitive areas;
2.1 Awareness raising and capacity building of key partner institutions, local
organizations and communities in participatory integrated landscape management
planning of VTCS for improved eco-health outcomes;
2.2 Relevant national policies and legislation for enabling environment for the
sustainable integrated landscape management reviewed and revisions
recommended to the Government;
2.3 Participatory sustainable integrated landscape management planning and
coordination platforms developed at district and local level;
2.4 Participatory sustainable integrated landscape planning/ management
guidelines developed for VTCS in socio-ecological sensitive areas.

17. Project Component 3:
Partnerships, awareness raising and capacity building for better sustainable
integrated landscape management in support of improved ecosystem services and
eco-health outcomes
3.1. Concept of Cascade Ecology established through workshops,
symposia and other knowledge products;
3.2 Knowledge mainstreamed to national extension, research
institutions, including universities, and policy makers and other
stakeholders on cascade ecology and landscape management,
ecosystem services and eco-health approaches.
Conference on ‘Cascade Ecology & Management
– 2021’
17-18 September, 2021
Organized by the Faculty of Agriculture,
Peradeniya, Sri Lanka

18. Project Component 4:
Knowledge, Information Management and Monitoring and Evaluation
4.1 Gender sensitive project monitoring system operating and
providing systematic information on progress in reaching expected
outcomes and targets
4.2 Project-related best practices, knowledge products and lessons
learned systematized and published for a variety of audiences and
stakeholder groups

19. Baseline Survey
of the Healthy Landscape Project
Study Team:
• Dr. P. B. Dharmasena, Team Leader/ Agriculture Specialist
• Prof. Renuka Silva, Food & Nutrition Security Specialist, Wayamba University of Sri Lanka
• Dr. H. K. Kadupitiya, Deputy Team Leader/ Land Degradation Assessment and GIS Specialist
• Prof. Keminda Hearth, Ecosystem Services Assessment Specialist, Wayamba University of Sri Lanka
• Mr. Sujith S. Ratnayake, Senior Technical Coordinator, Landscape and Climate Change Impact Modelling
Specialist, UNE, Australia
• Dr. Ananda Chandrasekera, Nutrition Security Specialist, Wayamba University of Sri Lanka
• Mr. Sarath Ekanayake, Terrestrial Biodiversity Assessment Specialist, IUCN
• Dr. Sudeepa Sugathadasa, Medicinal Plants Specialist, Bandaranaike Memorial Ayurvedic Research
Institute BMARI
• Dr. Manjula Ranagalage, LULC Dynamics Assessment Specialist, Rajarata University of Sri Lanka
• Ms. Ramani S, Rajapakse, Aquatic Biodiversity Assessment Specialist, NARA
• Dr. Champika S. Kariyawasam, Invasive Species Impact Modelling Specialist, UNE, Australia
International Coordinator: Prof. Danny Hunter, Senior Scientist, Bioversity International and CIAT, Rome, Italy
Mr. Dharshana Gunarathane, Chief Administrative Coordinator, Ministry of Environment
Ms. Dilshani Gunawardena, GIS Mapping and Modelling Technical Assistant

20. Project Sites
Major
Reservoir
Village Tank
Cascade System
(VTCS)
DS Divisions No. of
tanks
Extent (ha)
Nachchaduwa Mahakanumulla Ipalogama, Thirappane 29 4,717
Thirappane Thirappane, Ipalogama,
Kekirawa
10 2,206
Ulagalle Thirappane, Kekirawa 28 5,127
Horiwila Palugaswewa Palugaswewa 14 2,022
Bellankadawala Palugaswewa, Dambulla 28 4,995
TOTAL 109 19,067

21. Project Sites

23. Land Degradation Status
• Land Degradation types:
• Surface erosion and loss of topsoil;
• Heavy agro-chemical use - increased frequency
and severity of pests/ diseases incidences;
• Fertility decline and reduced organic matter
content;
• Decline of quality and species composition/
diversity;
• Reduction of vegetative cover;
• Increase in invasive tree species;
• Loss of habitats;
• Increased tank water losses and capacity
reduction;
• River bank erosion; and
• Reduction of the buffering capacity of wetland
areas.

24. Conclusions from Land Degradation Study
• Most of the areas are not managed properly
and Sustainable Land Management (SLM)
practices are not adopted.
• Nature of Land use is the most crucial factor
determining the magnitude of land
degradation
• LADA-WOCAT approach which has been
globally recognized and well tested, can be
confidently applied for all the land categories
in VTCS zones.
In many tanks kattakaduwa (downstream
reservation) has been completely encroached
by paddy farmers

25. Biodiversity Assessment
Important Facts from Terrestrial Biodiversity
• Ecosystem diversity ranges from near natural systems to man-made
agricultural systems.
• Home gardens and natural forests are sustaining more biodiversity and
yielding better ecosystem services.
• Kattakaduawa takes the lead in sustaining high animal diversity.
• Livelihoods of cascades rely on ecosystem services including
pollination, biological pest control, maintenance of soil fertility and
hydrological services.
• Intensive agricultural practices cause loss of wildlife habitat,
sedimentation of tanks, greenhouse gas emission, and pesticide
poisoning of humans and non-target species.

26. Biodiversity Assessment
Important Facts from Terrestrial Biodiversity
• Establishment of an ethno botanical garden can showcase
most of the agro-biodiversity for wider awareness.
• Practices can be introduced to increase crop land
productivity such as low cost controlled environment
agriculture for discouraging natural area encroachments.
• Tree cover can be increased in rainfed areas through
introduction of high income generating crops such as
mango, guava, sour sops (anoda), coconut etc.
• Traditional knowledge must be protected, preserved and
encouraged.
• A pilot project on cascade ecotourism can be initiated for
visiting natural areas in order to learn, study and carry out
activities in environmental friendly manner.

27. Biodiversity Assessment
Important Facts from Aquatic Biodiversity
• Proper management of riparian areas together
with vegetation is needed to maintain the
biodiversity.
• Best management practices such as home garden
improvement, traditional rice farming, crop
diversification and fisheries & livestock
development are required to ensure healthy food
and to minimize adding excess nutrition load into
water.
• Traditional wisdom associated with VTCS in
particular to develop resilience for climate
change should be documented.

28. Biodiversity Assessment
• Home gardens of indigenous practitioners contain multiple crops including large number of
medicinal and medicinal edible plants.
• These home gardens act as units of ex-situ conservation of medicinal plants as well as
providing medicine, variety of nutritious foods and other uses for households and in some
instant for income generation.
• Cultivation of food crops with high medicinal value is not much practiced at home garden
level.
• Promoting cultivation of medicinal edible plants with high demand and market value in
home gardens can make substantial contribution to family‟s income.
• Limited extension advices cause serious drawback of knowledge on medicinal plants.
• Awareness and education on conservation, cultivation and value of medicinal plants are
essential for younger generation in these areas.
• At the village level people should establish community-based organization to protect and
enhance their environment as well as faunal and floral diversity.
Important Facts from Medicinal Plant Biodiversity

29. Ecosystem Services Assessment - Provisional Services Identified
Provisional services
• Paddy and other cereals,
• Legumes and other seed crops,
• Leafy vegetables,
• Vegetables and tuber crops,
• Clean/ fresh water for drinking and domestic use,
• Irrigation water,
• Inland fishery,
• Livestock, fodder and grasses,
• Sedges and other alternative plants,
• Herbals/ medicinal plants and materials,
• Ecotourism.

30. Ecosystem Services Assessment – Regulatory Service identified
• Control floods/ flood protection,
• Groundwater recharge and flow
maintenance,
• Water purification,
• Local and global climate regulation,
• Pollination,
• Soil nutrient and erosion regulation.

31. Ecosystem Services Assessment – Support Services Identified
• Food and nutrient
security,
• Biodiversity conservation
and maintenance

32. Ecosystem Services Assessment – Cultural Services Identified
• Recreational and
aesthetic value,
• Traditional knowledge
and values,
• Culture,
• Traditions, customs and
practices,
• Peace, harmony and
corporation.

33. Food Security and Human Health - Recommendations from the Study
1. Policies and regulations are required for the
biodiversity conservation and sustainable use
interventions.
2. Interventions should be done to conserve and
restore the village tanks with the involvement of
multi-stakeholders.
3. Farmer awareness and provision of necessary
technical and infrastructure support.
4. Plan and implement programmes which promote
the traditional and indigenous knowledge in their
food production systems.
5. Conduct research to mainstream indigenous
knowledge in conserving and popularizing the
traditional landraces that will result in
implementing effective adaptation action on the
ground.

34. Food Security and Human Health - Recommendations from the Study
1. Provide farmers necessary awareness and inputs
to enhanced popularity of organic and locally
grown food.
2. Programmes should be carried out to build
knowledge and understanding of native
agriculture and food systems and help promote
native communities‟ innovative ideas and best
practices.
3. Programmes should be conducted to transfer the
traditional knowledge in food culture using novel
behavioural communication techniques.
4. Promotion of local traditional agriculture and
local cuisines can be used to promote agro-
tourism, eco-tourism and cultural activities.
5. Action has to be taken to provide access to better
medical facilities to vulnerable groups such as
elderly, adults and school children and awareness
and behavioural change communication actions
must be taken.