Planet Earth has always been in a State of Change; the rate of change has never been constant Global Issues in Nematode Ecology and Management Commonalities and Differences in Nematode Issues across the Globe Howard Ferris Department of Nematology University of California Davis
Big Issues in World Agriculture, Economy and Ecology 1. Global climate change and mitigation measures 2. Fossil fuel depletion and costs Context: the need to provide food, fiber, water, and shelter for 6.7 billion people 3. Global trade agreements 4. Land ownership and land tenure …………and their interlinkages
Climate Change Big Issues in World Agriculture, Economy and Ecology Energy Costs Mitigation Mitigation Adaptation: Shifts in land-use patterns and management practices Mitigation- slowing the process Adaptation- minimizing the effect on services Mitigation Mitigation Trade Agreements Land Tenure
How are different nematode functional groups affected by climate and land-use change? Provide Services Provide Disservices Mitigation tradeoffs?
A simplistic analysis of climate change effects on soil nematodes Nematode winners and losers? But.the same factors affect growth and tolerance of hosts, prey and natural enemies of the nematodes. ….And management decisions of the environmental steward. So, the net outcome is unpredictable, at least by me.
Thermal amplitude of bacterivores Physiological Ecology We have some of the necessary information…… Ferris et al., 1995
But we need to think at a larger scale…… A conceptual framework for comparing trade-offs on ecosystem services Foley et al., Science 309, 570 -574 (2005)
Total area 50 ha. Each plot 1 ha. Treatments 14 Replications 3 Landscape Ecology Professor Shenglei Fu, Chinese Academy of Sciences: Mitigation - reforestation – altering climate Adaptation - vegetation mixes to maximize functions and services • Services: • pulp production • wildlife habitat • pollination • refugia • erosion control • groundwater quality • carbon sequestration • decomposition • nutrient cycling • nutrient retention • mineralization • soil quality • esthetics • public education China, 2007
Farmscape Ecology • Temperature effects • Rhizosphere interactions • Host effects Mitigation/Adaptation: Coffee under tree shade – Costa Rica, 2008
Adaptations Winter cover crop – bell beans California, 2006 • Soil fertility • Organic matter • Food web activity • Soil structure • Fossil fuel reduction • Habitat conservation • Food web activity • Soil structure No-till soybeans, Brazil, 2006
Sustainability is a journey, not a destination (Howard Shapiro, Mars Inc.) Soil Fauna Environmental and economic pressures Adapted from: Meine van Noordwijk World Agroforestry Centre Bogor, Indonesia Sustainability of . . . Is life still possible on this planet? Sustainagility: Migration to another region of planet Non-farming livelihoods Sustainagility: Shift to non-farming livelihood New farming system Sustainagility: Change farming system New cropping system Sustainagility: Change cropping system New crops/animals Sustainagility: Change crops/animals Current crops/animals
Consistent N-yield over 75 years without input • N-yield similar to that of high input wheat Structure Index Basal Index Land-use change in Kansas: Soil food web effects Community Ecology From Glover et al., subm.
P P F O Pr O Pr F B B Regulation Soil Food Web: Functions and Services in relation to punctuated and continuous resource supply Mineralization Easier to go in this direction Reverting to prairie? Need to understand invasion biology of omnivores and predators
California, 1999 Some Global Issues in Nematode Management Nematicide tradeoffs – production enhancement vs. economics, environmental hazards and food web simplification (pesticide treadmill) Zimbabwe, 1961
California, 1973 An ideal: Biodiversity-friendly nematicides that protect roots without killing non-target soil organisms: “immunogenic nematicides” Impact on Higher Trophic Levels Korthals et al., 1998
Global Issues in Nematode Management Management practices in industrialized agriculture result in food web simplification – cp1 and cp2 bacterivores and fungivores predominate Reduction in cp3, 4, 5 higher trophic levels Farmscape Ecology Costa Rica, 2008
Conventional Bacterivore Biomass Organic Herbivore Biomass Bacterivore Biomass • Global Issues in Nematode Management • Nematode biomass in soil food web
border cells protozoa arthropods nematodes Molecular Ecology What is the rhizosphere effect of Theobroma on Musa? molecular signals Hawes et al., 1998 Farrar et al., 2003 Hirsch et al., 2003
Other Nematode Services – enhancing soil fertility Behavioral Ecology An example of positive and negative feedback bacteria and bacterivore nematodes 0 nematodes with five nematodes with twenty nematodes Fu et al. 2005
The Importance of Biodiversity California, 1996
Crossover Rotations – Oostenbrink, 1959 FAO - redrawn A B Corn, cassava, beans - Congo C D E Netherlands, 1965 F A B C D E F California, 1982 Depleted Soils of Africa
Land-use Change: TheGlobal Spread of Nematodes Examples: Citrus – Tylenchulus semipenetrans worldwide Grapevines and their nematode complexes Soybeans and Heterodera glycines Cereals and grass seeds – Anguina spp. Potatoes – Globodera and Meloidogyne spp. Bananas and Radopholus, Helicotylenchus, Meloidogyne, Pratylenchus. Invasion Biology Some nematodes have attributes of invaders: Arrival Establishment Integration Spread Detection Escape Effects of global exploration, human migration, modern transportation: Despite regulatory efforts, major crops throughout the world support the same nematode complexes. Most major nematode pest problems in California are caused by non-native species.
Sugarbeet Cyst Nematode - Heterodera schachtii sugarbeet production sugarbeet cyst nematode
Adaptation to Nematode Globalization and Land-use Change • Sources of resistance and other control/mitigation measures should apply in new • areas of production. • Caveat: consider the local acceptability of new varieties and the availability of appropriate infrastructure/technology. • But….. • Every year, we lose between 17,000 and 100,000 species as the result of human activities (The Sixth Extinction. Leakey and Lewin, 1995) • That represents an enormous loss of functions, services and genes. • The problem is compounded by proprietary ownership of resistance genes and • commercialization of seed sources, reducing local selection of desirable traits.
Svalbard Global Seed Vault will store three million different crop varieties in case of a worldwide catastrophe. Genetic diversity is a common legacy – it should be conserved, not owned Dr. Vandana Shiva’s movement concerned with saving seeds, trading seeds, farming without corporate-derived seed. Ghandi: “You cannot monopolize this which we need for life.”
Global Issues in Nematode Ecology and Management: Summary and Research Directions…… • Organismal level: • Adapt knowledge from • biological models and microcosm • experiments • Farmscape and Landscape levels: • Adapt management to scale of system • Develop a biodiversity-friendly • landscape
Global Issues in Nematode Ecology and Management: Summary and Research Directions…… Thank you • Organismal level: • Adapt knowledge from • biological models and microcosm • experiments • Farmscape and Landscape levels: • Adapt management to scale of system • Develop a biodiversity-friendly • landscape