Ecosystem Ecology I. Introduction II. Energy Flow III. Biogeochemical Cycles IV. Productivity, Diversity, and Stability

A. Productivity

1. Gross Primary Productivity?

A. Productivity 1. Gross Primary Productivity Total photosynthetic productivity; CO 2 + H > Glucose + O 2

A. Productivity 2. Net Primary Productivity?

A. Productivity 2. Net Primary Productivity NPP = GPP - respiration (Plants use some of the energy they absorb; it is not stored as biomass. NPP is only the amount stored as new biomass.)

B. Diversity - Relationships with Productivity

1. Productivity increases diversity

- QUANTITATIVE EFFECT If you have more productivity at the base of a food web, then you can build a longer food chain (adding additional levels AND species)…. And then get keystone effects. B. Diversity - Relationships with Productivity 1. Productivity increases diversity

- QUALITATIVE EFFECT An increase in productivity may also occur because more types of food have been added. This may allow for more specialization at the next trophic level - and the coexistence of more species. B. Diversity - Relationships with Productivity 1. Productivity increases diversity

B. Diversity - Relationships with Productivity 1. Productivity increases diversity 2. Diversity increases productivity

- Sampling Effects More diverse communities are more likely to contain the most productive species, and thus raise the total 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 They all need the same things at the same concentrations; have to place them far apart to reduce competition. Polyculture 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.

- Positive Interactions More diverse communities may contain species that benefit other species, and thus increase the productivity of the whole community

Monoculture They all need the same things at the same concentrations; have to place them far apart to reduce competition. Polyculture Nitrogen fixing legumes (beans) nutrify the soil, increasing the growth of other plants without beans with beans

Diversity and Productivity in a Long-Term Grassland Experiment Tilman, et al Science Cedar Creek Ecosystem Science Reserve m x 9 m plots - 1, 2, 4, 8, or 16 species randomly chosen from a pool of 18 species: 4 species, each, of C4 grasses, C3 grasses, legumes, non-legume forbs; 2 species of woody plants. - ~35 replicates of each treatment

Diversity and Productivity in a Long-Term Grassland Experiment Tilman, et al Science 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.

Diversity and Productivity in a Long-Term Grassland Experiment Tilman, et al Science 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 (can’t just be sampling effect).

Diversity and Productivity in a Long-Term Grassland Experiment Tilman, et al Science 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 complementa rity in natural systems…

Additional Experiments and Results: - Foliar fungal disease incidence decreased at higher diversity because of greater distance between individuals of a species, and resultant lower rates of disease spread (Mitchell et al. 2002). (“Dilution Effect”) - Greater plant diversity led to greater diversity of herbivorous insects, and this effect continued up the food web to predator and parasitoid insects (Haddad et al. 2001). (“Qualitative Effects of Diversity”)

Additional Experiments and Results: - Fewer novel plant species invaded higher diversity treatments because of their lower soil NO3 levels, greater neighborhood crowding and competition, and greater chance that functionally similar species would occur in a given neighborhood (Figs 3; Naeem et al. 2000, Kennedy et al. 2002, Fargione et al. 2003, Fargione and Tilman 2005a, 2005b). Greater plant species numbers led to greater ecosystem stability (lower year-to-year variation in total plant biomass) but to lower species stability (greater year-to-year variation in abundances of individual species), with the stabilizing effect of diversity mainly attributable to statistical averaging effects and overyielding effects (Fig 4; Tilman et al, submitted). Data gathered this past field season shows that soil total C has now become an increasing function of plant species numbers (Fig 5).

Additional Experiments and Results: - Greater plant species numbers led to greater ecosystem stability (lower year-to- year variation in total plant biomass) but to lower species stability (greater year-to-year variation in abundances of individual species).

Additional Experiments and Results: - Stored soil carbon increases with diversity.

- Effects of Genetic Diversity Example Crutsinger, et al Science 313: Methods: m 2 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 Science 313: Results: 1: ANPP correlated with number of genotypes in plot.

- Example Crutsinger, et al Science 313: 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 Science 313: Results: 3. The effects were non-additive; there were more arthropods (and herbivores and predators) in 6 and 12 species plots than predicted by adding the richness values of the monocultures.

- Example Crutsinger, et al Science 313: Results: 4: ANPP increase is NOT due to a sampling effect. Evidence favors niche complementation (p = 0.07).

- Example Crutsinger, et al Science 313: Results: 5: Increase in herbivorous insects due to both MORE food (ANPP - quantitative effect) and DIFFERENT food (niche differentiation - qualitative effect).

- Example Crutsinger, et al Science 313: Results: 6: Increase in predator richness due to increase in herbivore richness, not AMOUNT of food. Some herbivores were only associated with some genotypes.

- Example Crutsinger, et al Science 313: Conclusions: ANPP increased with genetic diversity, probably as a function of niche complementarity.

- Example Crutsinger, et al Science 313: Conclusions: ANPP increased with genetic diversity, probably as a function of niche complementarity. Diversity in higher trophic levels increased with increased ANPP and greater genetic diversity. Herbivore richness is a function of both increased abundance and niche complementarity. Predators increase largely due to a greater variety of herbivores.

- Example Crutsinger, et al Science 313: Conclusions: ANPP increased with genetic diversity, probably as a function of niche complementarity. Diversity in higher trophic levels increased with increased ANPP and greater genetic diversity. Herbivore richness is a function of both increased abundance and niche complementarity. Predators increase largely due to a greater variety of herbivores. So, genetic variation WITHIN species, and not just diversity among species, may be critical to the conservation of productive and species- rich communities.

C. Effects on Stability

1. Types - "resistance to change" - "resilience after change"

C. Effects on 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. Effects on Stability Biodiversity and Ecosystem Functioning: Current Knowledge and Future Challenges. Loreau, et al Science 294: As richness increases, communities become less variable (more stable).

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

Decomposition rapid Absorption rapid Volatiles released Stimulate condensation and precipitation Rainforests feed themselves and water themselves.

CUT FOREST DOWN REDUCE RAINFALL... REDUCE NUTRIENTS INCREASE FIRE Select for fire-adapted grasses.... rainforest doesn't come back....

RAINFOREST (wet, few fires) GRASSLAND (dry, many fires) "Multiple Stable States"

We are dependent on the environment for food and resources. Ideally, we would like a STABLE, PRODUCTIVE supply of these resources.... right?? FEAST FAMINE

(We don't want "boom and bust", "feast and famine" scenarios....) FEAST FAMINE

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 ?

We are playing jenga with our life support systems... de Ruiter et al Food Web Ecology: Playing Jenga and Beyond Science 309:

“The pale blue dot” …. Earth from the Voyager spacecraft, > 4 billion miles away

EarthMars CO %95% N2N2 77%2.7% H2OH2O1%0.007% Ar0.93%1.6% O2O2 21%trace

Earth History 4.5 bya: Earth Forms4.0 bya: Oldest Rocks3.4 bya: Oldest Fossils bya: Oxygen 1.8 bya: first eukaryote 0.9 bya: first animals 0.5 bya: Cambrian0.24 bya:Mesozoic0.065 bya:Cenozoic 4.5 million to present (1/1000th of earth history)

All genera “well described” genera The “big five” Mass Extinction Events Millions of Years Ago Thousands of Genera

Permian mass extinction: 96% of all marine species and 70% of terrestrial vertebrate species (% of Genera)

WHY?

ecological collapse Almost all animals over 25kg (~55 lbs) went extinct. (The things that require the most energy to survive)

BIODIVERSITY NOW

Millenium Ecosystem Assessment (2006)

Detritivores Pollinators Insect predators Herbivores

Pollinators Insect Parasitoids (lay eggs on other insects) Insect Predators

Malagasy Sunset Butterfly Jewel Bug madagascar-sunset Herbivores Pollinators Parasites Detritivores

Herbivores Detritivores

PRODUCERS

Most vertebrate species are fishes

ml then Herbivores, Predators, Detritivores, Pollinators

But do we NEED all these species??

There’s a lot of redundancy in nature…

Are all species equally important? If not, which ones are critical?

with without

We don’t know which species are critical So we need to save them all to maintain ecosystem function

But what does biodiversity do??

1) Biodiversity increases “productivity”... FOOD

Monoculture They all need the same things at the same concentrations; they compete.

MonoculturePolyculture 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. They all need the same things at the same concentrations; they compete. “Niche Complementarity”

MonoculturePolyculture Nitrogen fixing legumes (beans) nutrify the soil, increasing the growth of other plants. And you have beans! without beans with beans They all need the same things at the same concentrations; they compete. “Positive Effects”

2) Biodiversity improves ecosystem services Estimates of various Ecosystem Services - $U.S. trillions Ecosystem services Value (trillion $US) Soil formation17.1 Recreation3.0 Nutrient cycling2.3 Water regulation and supply2.3 Climate regulation (temperature and precipitation) 1.8 Habitat1.4 Flood and storm protection1.1 Food and raw materials production 0.8 Genetic resources0.8 Atmospheric gas balance0.7 Pollination0.4 All other services1.6 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.

3) Aesthetics and Inspiration: Biodiversity enriches our cultures

How is our biodiversity doing? Genetic diversity within species Species diversity in communities Ecosystem diversity

How is our biodiversity doing? Humans used hundreds of crop species worldwide; now 3 species (rice, wheat, corn) provide 60% of our calories from crop plants. According to the FAO of the UN, 70% of the genetic diversity of crop plants has been lost in the last 75 years as we’ve shifted to industrial farming and the use of GM strains.

How is our biodiversity doing? 2000 Pacific Island bird species (15% of global total) have gone extinct after human colonization 20 of the 297 mussel species in N.A. have gone extinct in the last 100 years; 60% are endangered 40 of 950 fish species in N. A. have gone extinct in the last century; 35% are threatened or endangered currents.htm?customel_dataPageID_206517= Yellow-finned cutthroat trout

How is our biodiversity doing? 1 in 4 mammal species is endangered 1 in 8 bird species is endangered 1 in 3 amphibian species is endangered 48% of primate species are threatened Data from:

How is our biodiversity doing? 35% of mangrove habitat has been lost in the last 20 years In the Caribbean, hard coral cover has declined from 50% to 10% in the last 20 years Since 2000, 232,000 sq miles of old growth forest have been lost (size of Texas).

WHY?

7 billion in 2011 (12 years later)

13,000 sq kilometers is about the size of Connecticut

Extent of Virgin Forest, Contiguous U. S.

Millenium Assessment 2006

1 10 million? Humans use/control 40% of the ‘food’ produced on the planet.

Fragmentation

PLANTS HERBIVORES CARNIVORES LARGE AREA OF HABITAT Area Effects Fragmentation

HABITAT FRAGMENTATION Fragmentation

HABITAT FRAGMENTATION Fragmentation 1)Carnivores lost - (reduce diversity) 2)Herbivores compete – (reduce diversity) 3)Plants overgrazed – (reduce diversity)

We are a geological force, operating on an ecological timescale Mountaintop removal in West Virginia

We are a geological force, operating on an ecological timescale Gold mining in Peruvian Amazon

We are a geological force, operating on an ecological timescale

Hmmmm….

All genera “well described” genera The “big five” Mass Extinction Events Millions of Years Ago Thousands of Genera Sixth major mass extinction event - NOW

22 May 2010 –Secretary-General Ban Ki-moon: “Biodiversity loss is moving ecological systems ever closer to a tipping point beyond which they will no longer be able to fulfill their vital functions.”

What Can We Do? We need to protect and preserve large intact, biodiverse ecosystems.

This is great, but it ain’t gonna do it…

We need to rethink our model of community… Development nature Development

We need to find out what’s out there!

We need to appreciate the societal and economic value of biodiversity Corporate Social Responsibility (CSR) “Protection of biodiversity should be the underlying reason for every CSR effort. Biodiversity loss is the most severe threat to human-wellbeing on the planet. It rates even higher than climate change and related problems…. The head of Deutsche Bank's Global Markets predicts that our current rate of biodiversity loss could see 6% of global GDP wiped out as early as The Economics of Ecosystems and Biodiversity executive summary (2010) The Economics of Ecosystems and Biodiversity executive summary (2010) reports that “over 50% of CEOs surveyed in Latin America and 45% in Africa see declines in biodiversity as a challenge to business growth. In contrast, less than 20% of their counterparts in Western Europe share such concerns”

If we recognize the grandeur of life, we might appreciate it…

If we appreciate it, we might value it…

If we value it, we might sustain it…

If we sustain it, we might be able to sustain our societies and economies, as well. ECONOMY SOCIETY ENVIRONMENT

If we don’t, we won’t… A few extinct animal species. Thylacine Quogga Golden Toad Tecopa Pupfish Yangtze River Dolphin Vietnamese Rhinoceros