What does biodiversity do??

1. Diversity increases productivity and stability

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 niche complementarity or positive effects must be occurring. So, many random assemblages of multiple species have biomass above that of the most abundant monoculture. And we might expect greater niche complementarity in natural systems…

Biodiversity and Ecosystem Functioning: Current Knowledge and Future Challenges. Loreau, et al. 2001. Science 294: 804 - 808 As richness increases, productivity become less variable (more stable).

But what else does biodiversity do??

2) Biodiversity improves ecosystem services Estimates of various Ecosystem Services - $U.S. trillions Ecosystem services Value (trillion $US) Soil formation 17.1 Recreation 3.0 Nutrient cycling 2.3 Water regulation and supply Climate regulation (temperature and precipitation) 1.8 Habitat 1.4 Flood and storm protection 1.1 Food and raw materials production 0.8 Genetic resources Atmospheric gas balance 0.7 Pollination 0.4 All other services 1.6 Total value of ecosystem services 33.3 Source: Adapted from R. Costanza et al., “The Value of the World’s Ecosystem Services and Natural Capital,” Nature, Vol. 387 (1997), p. 256, Table 2. TOTAL GLOBAL GNP (1997) = 18 trillion.

GLOBAL GDP 2011: $75 trillion

Based on different criteria, this is the ecosystem value we lost in that 14 year span. GLOBAL GDP 2011: $75 trillion

3) Aesthetics and Inspiration: Biodiversity enriches our cultures

3) Aesthetics and Inspiration: Biodiversity enriches our cultures

4) Fights Disease Lyme Disease: - fragmentation reduces patch size - abundance of predators like fox declined - white-footed mice (host of Borrela burgdorferi bacterium) increase. - increase host density, increase infection rate of ticks.

High Relative Abundance of Hosts Low Relative Abundance of Hosts West Nile Virus Low Diversity: High Relative Abundance of Hosts High Diversity: Low Relative Abundance of Hosts Transmission rates to humans are higher in less diverse systems Swaddle and Carlos, 2008. PLoS one 3:e2488

Intrinsic Value Utilitarian Why Preserve Diversity/Nature? Ecosystem Services?

Biodiversity: Patterns and Processes The Species-Area Relationship 1. The pattern

"species - area relationship"

"species - area relationship" Breedings Birds - North Am.

"species - area relationship" Number of Bat Species log(N) Island Area log(square km)

Biodiversity: Patterns and Processes The Species-Area Relationship 1. The pattern 2. The Theory of Island Biogeography

MacArthur and Wilson (1967) THEORY OF ISLAND BIOGEOGRAPHY Edward O. Wilson Prof. Emer., Harvard Robert MacArthur 1930-1972

MacArthur and Wilson (1967) THEORY OF ISLAND BIOGEOGRAPHY - Species Richness is a balance between COLONIZATION (adds species) and EXTINCTION (subtracts species)

- Colonization Increases with Area - larger target - more habitats Mainland

confirmation: greater immigration rate on larger islands

- Colonization Increases with Area - larger target - more habitats

- Colonization Increases with Area - larger target - more habitats - Extinction Decreases with Area - more food means larger populations that are less likely to bounce to a size of "0" (extinction)

- Extinction Decreases with Area Reduced Turnover on larger islands Wright, S.J. 1980. Density compensation in island avifaunas. Oecologia 45: 385-389.     Wright, S. J. 1985. How isolation affects rates of turnover of species on islands. Oikos 44:331-340.    

COL - large RATE EXT - small COL - small EXT - large SMALL LARGE species richness

- Colonization Decreases with Distance - fewer species can reach Mainland

- Colonization Decreases with Distance - fewer species can reach saturation is the % of species found on a patch of mainland that size

- Extinction Increases with Distance - recolonization less likely at distance Mainland "Rescue Effect"

- Extinction Increases with Distance - recolonization less likely at distance Wright, S.J. 1980. Density compensation in island avifaunas. Oecologia 45: 385-389.     Wright, S. J. 1985. How isolation affects rates of turnover of species on islands. Oikos 44:331-340.

COL - close RATE EXT - far COL - far EXT - close far close species richness

equilibria Equilbrium Island Biogeography & Turnover Turnover on "Landbridge" islands (California Channel Islands) Island Area km2 Distance km Bird Spp. 1917 Bird Spp. 1968 Extinctions Human Introd. Immigrations Turnover % Los Coronados 2.6 13 11 4 36 San Nicholas 57 98 6 2 50 San Clemente 145 79 28 24 9 1 25 Santa Catalina 194 32 30 34 Santa Barbara 61 10 7 3 62 San Miguel 42 15 8 46 Santa Rosa 218 44 14 Santa Cruz 249 31 37 5 17 Anacapa 2.9 21 Diamond, J.M. 1969. Avifaunal equilibria and species turnover rates on the Channel Islands of California. Proc. Natl. Acad. Sci 64: 57-63.   Jones, H.L. and Diamond, J.M. 1976. Short-time-base studies of turnover in breeding bird populations on the Channel Islands of California. Condore 73: 526-549. [+]     equilibria

equilibria and turnover Equilbrium Island Biogeography & Turnover Turnover on "Landbridge" islands (California Channel Islands) Island Area km2 Distance km Bird Spp. 1917 Bird Spp. 1968 Extinctions Human Introd. Immigrations Turnover % Los Coronados 2.6 13 11 4 36 San Nicholas 57 98 6 2 50 San Clemente 145 79 28 24 9 1 25 Santa Catalina 194 32 30 34 Santa Barbara 61 10 7 3 62 San Miguel 42 15 8 46 Santa Rosa 218 44 14 Santa Cruz 249 31 37 5 17 Anacapa 2.9 21 Diamond, J.M. 1969. Avifaunal equilibria and species turnover rates on the Channel Islands of California. Proc. Natl. Acad. Sci 64: 57-63.   Jones, H.L. and Diamond, J.M. 1976. Short-time-base studies of turnover in breeding bird populations on the Channel Islands of California. Condore 73: 526-549. [+]    

Dramatic evidence that, although the communities had recovered in terms of species richness, the composition was very different with typically about 80% of the species turning over.

Biodiversity: Patterns and Processes The Species-Area Relationship 1. The pattern 2. The Theory of Island Biogeography 3. Why is this important? Fragmentation

- all habitats except the atmosphere are islands. - Why is this important? - all habitats except the atmosphere are islands. Continents - big islands

Minnesota: Land O'Lakes

"Sky Islands" High elevation habitats separated by inhospitable (desert) habitat.

- Why is this important? - all habitats except the atmosphere are islands. - human activity fragments a landscape, making lots of islands, too.

Bolivia has lost 50% of its rainforest in last 30 years

Even Costa Rica has lost 95% of its old growth forest that is outside of national parks...