320 likes | 912 Views
B. Diversity 3. Relationships with Productivity a. Productivity increases diversity b. Diversity increases productivity B. Diversity 3. Relationships with Productivity a. Productivity increases diversity b. Diversity increases productivity - Sampling Effects
E N D
B. Diversity 3. Relationships with Productivity a. Productivity increases diversity b. Diversity increases productivity
B. Diversity 3. Relationships with Productivity a. Productivity increases diversity b. Diversity increases productivity - Sampling Effects More diverse communities are more likely to contain the most productive species, and thus raise the total productivity.
B. Diversity 3. Relationships with Productivity a. Productivity increases diversity b. Diversity increases productivity - Niche Complementarity More diverse communities are more likely to contain different types of species that use different types of energy... thus more efficiently harvesting the available energy
Monoculture Polyculture They all need the same things at the same concentrations; have to place them far apart to reduce competition. Combinations of different plants can be planted at higher density, and they use different "niches" and coexist. Even if abundance of "most productive" species, drops, this loss can be offset.
B. Diversity 3. Relationships with Productivity a. Productivity increases diversity b. Diversity increases productivity - Positive Interactions More diverse communities may contain species that benefit other species, and thus increase the productivity of the whole community
Monoculture Polyculture without beans with beans They all need the same things at the same concentrations; have to place them far apart to reduce competition. Nitrogen fixing legumes (beans) nutrify the soil, increasing the growth of other plants
Diversity and Productivity in a Long-Term Grassland Experiment Tilman, et al. 2001. Science 294. 843 - 845 Dotted line is biomass in a monoculture of the most productive species. Higher productivity than this, at higher richness values, means nich complementarity or positive effects must be occurring.
- Effects of Genetic Diversity Example Crutsinger, et al. 2006. Science 313: 966-968. Methods: - 63 1m2 plots, each containing 12 plants of all goldenrod. - The plants in a plot represent either 1, 3, 6, or 12 genotypes, randomly selected from a pool of 21 genotypes.
- Example Crutsinger, et al. 2006. Science 313: 966-968. Results: 1: ANPP correlated with number of genotypes in plot.
- Example Crutsinger, et al. 2006. Science 313: 966-968. Results: 1: ANPP correlated with number of genotypes in plot. 2: Total insect species diversity, and diversity of herbivores and predators, correlate with ANPP and number of genotypes per plot.
- Example Crutsinger, et al. 2006. Science 313: 966-968. Results: 3: ANPP increase is NOT due to a sampling effect, but due to niche complementarity among genotypes
- Example Crutsinger, et al. 2006. Science 313: 966-968. Results: 4: Increase in herbivorous insects due to both MORE food (ANPP) and DIFFERENT food (niche differentiation).
- Example Crutsinger, et al. 2006. Science 313: 966-968. Results: 5: Increase in predator richness due to increase in herbivore richness, not AMOUNT of food.
- Example Crutsinger, et al. 2006. Science 313: 966-968. Conclusions: ANPP increased with genetic diversity. Diversity in higher trophic levels increased with increased ANPP and greater genetic diversity. So, genetic variation WITHIN species, and not just diversity among species, may be critical to the conservation of productive and species-rich communities.
I. Climate II. Biomes III. Productivity, Diversity, and Stability A. Productivity B. Diversity C. Stability
C. Stability 1. Types
C. Stability 1. Types - "resistance to change"
C. Stability 1. Types - "resistance to change" - "resilience after change"
C. Stability 1. Types 2. Relationships with diversity
C. Stability 1. Types 2. Relationships with diversity - more diverse communities are less susceptible to single "types of disturbance" - (a pest, a flood, a drought) - because the many species are unlikely to be sensitive to the same thing.
C. Stability 1. Types 2. Relationships with diversity - more diverse communities are less susceptible to single "types of disturbance" - (a pest, a flood, a drought) - because the many species are unlikely to be sensitive to the same thing. monoculture - sensitive to one pest Diversity increases resistance
C. Stability Biodiversity and Ecosystem Functioning: Current Knowledge and Future Challenges. Loreau, et al. 2001. Science 294: 804 - 808
C. Stability 1. Types 2. Relationships with diversity - diverse communities may recover more rapidly, too (resilience).... but they may not. Fisheries ... yes Rain forest... maybe not
Stimulate condensation and precipitation Volatiles released Rainforests feed themselves and water themselves. Decomposition rapid Absorption rapid
CUT FOREST DOWN Select for fire-adapted grasses.... rainforest doesn't come back.... REDUCE RAINFALL... REDUCE NUTRIENTS INCREASE FIRE
RAINFOREST (wet, few fires) "Multiple Stable States" GRASSLAND (dry, many fires)
I. Climate II. Biomes III. Productivity, Diversity, and Stability A. Productivity B. Diversity C. Stability D. Summary
D. Summary We are dependent on the environment for food and resources. Ideally, we would like a STABLE, PRODUCTIVE supply of these resources.... right?? FEAST FAMINE
D. Summary (We don't want "boom and bust", "feast and famine" scenarios....) FEAST FAMINE
D. Summary We are dependent on the environment for food and resources. Ideally, we would like a STABLE, PRODUCTIVE supply of these resources.... right?? (We don't want "boom and bust", "feast and famine" scenarios....) STABILITY ? PRODUCTIVITY
D. Summary We are dependent on the environment for food and resources. Ideally, we would like a STABLE, PRODUCTIVE supply of these resources.... right?? (We don't want "boom and bust", "feast and famine" scenarios....) STABILITY DIVERSITY ..... right...... PRODUCTIVITY