ES: Community Ecology, Population Ecology, and Sustainability Chapter 6

KEY IDEAS What determines the number of species in a community? How classify according to roles in community? How do species interact? Communities respond to environmental changes? How do reproductive patterns differ in species? Human Impact? How do Niches Change? Sustainability? Natural Capital?

Lets talk Niche

NICHE and ADAPTATIONS (4.3) & ( 6.3) A Niche is an organisms role in the ecosystem. It affects it and others survival and reproductive Fitness(reproduction) No two organisms occupy the same niche Habitat: Where it lives

Niche: Fundamental and Realized Realized the actual range available due to competition Fundamental Full potential range that can theoretically used Chthamalus : fundamentally could live in many zones. Balanus moves him out.

NICHE Fundamental niche Realized Niche Describes the potential a species has to be completely successful in using its resources to the fullest extent without competition,predation, or pressure from limiting factors. Describes what a species is actually going to do in terms of using its resources due to pressures from limiting factor s ,predation, or competition

Exclusion of an organisms niche Competitive Exclusion or interspecific exclusion Intraspecific Exclusion Competition between two species forms exclusion of each other . They Competitively exclude one another out of a niche .One of the competitors always overcomes the other. New niche may form or evolutionary shift or extinction When the same species exclude each other it is Intraspecific Exclusion. Niches Overlap

Competitive exclusion

When the same species exclude each other it is Intraspecific Exclusion The woodpecker Males characteristically forage on small trees or on small branches of large trees females typically forage on the trunks and larger limbs of large trees. The niches overlap, but the slight distinction limits competition between the sexes So long as there are enough resources species can share them.

Can lead to adaptations or radiation of the species

Radiation of the Species: adaptations form from competition creating speciation – new species

Resource Partitioning reduces or avoids competition Specialized traits evolve that allows them to share resources at different Times -temporal Ways- Ways they get food places - different areas of same resource One tree many resources

Speciation:Formation of a species through competition, limiting factors, and adaptations

Resource partitioning summary: forms adaptations that cause specialization and new niches

Limiting Factors ?DDLF – DDIF? Density Dependent Limiting factors (DDLF) Density Independent Limiting factors(DILF) Limiting factors that are intensified by the density of populations Are typically bioitc factors Competition Bacterial disease Symbiosis-species relationships Limiting factors that are NOT intensified by population numbers Are typically abiotic factors Climate Natural disasters Viral disease

6.1 Community Structure and Species Diversity Physical Appearance – Sizes, stratification and distribution of species (pg 110) Physical Appearance lends to species richness and evenness as physical appearance changes

Community Structure is Zoned Community Structure is Zoned. Zones are Wide and Varied due to many factors Aquatic Zones affected by temperature, amount of light, salinity,pressure,

Some other Factors cause these variances: Sunnier, warmer, drier, lighter, darker,moister, acidic, salinity,biomass abundant…

Zoned Life is Patchy…. (directly from your book!) Community structure also varies around its edges where transitions of communities take place.

Human Impact: Habitat Fragmentation Increases forest edge or buffers: Makes species more vulnerable to stresses like predators, fire, and creates barriers where species cannot colonize and finding food.

Species Diversity and Niche Structure Species Richness (number of species) Species Evenness (number of individuals within species) = Species Diversity Allows community a to differ from b to differ from c……… Typically a community is either rich or even but not both!

Species Diversity Types Species Richness The number of species in an areas of each species present. This is rrsity How rich are the species in your area? Species Evenness : how many of each species exists in that areanumber of members How even is the diversity? IF: Species A = 56 members Species B = 55 members Species C = 52 Then: species evenness is good but diversity is low! Rainforest, coral reef , deep sea, large tropical lakes have high species diversity but low species evenness (few members in each)

DIVERSITY CREATES NICHE STRUCTURE Highest in tropics and declines as move North and south from equator

Are Complex Communities more sustainable than Simple ones? Typically: Net Primary productivity indicates ecosystem is more resilient with species diversity of 30 -4 0 (complex) However, not conclusive, and still a hot environmental topic. Some believe simple communities have just enough diversity to survive. Agree: All communities need producers and decomposers .which producers and which are essential is the question.

Species Types 6.2

6.2 Species Types Native:Normally live and thrives in area Has competitors and Natural predators Non-Native,Invasive, Alien Have Migrated or been deliberately or accidentally transferred into an area Some have no effect: corn, chickens

Indicator Species Think : Range of Tolerance

Indicator Species Biological smoke alarms Fish, birds, amphibians, butterflies Indicate ecosystem health: pH, Habitat fragmentation, dissolved oxygen in water communities, pollution, reduction in stratospheric ozone, climate change, over hunting…

Amphibians as an Indicator Species Habitat loss-defragmentation Prolonged Draught Pollution – pesticides UV Radiation Parasites Overhunting Viral/Fungal diseases Non-native predators/competitors

WHY CARE? 1st – environmental health deterioration 2nd – Amphibians eat more pests and feed many others 3rd – They are genetic storehouse of pharmaceuticals Painkillers, antibiotics, burn treatment (biopharming)

Keystone Species A wedge shaped stone placed in an archway supporting the entire arch IF REMOVED: DRAMATIC !!!! Ecological Services go out all over

Keystone Species Have a huge effect on the species richness and evenness of an ecosystem. A keystone species disappears can lead to population crashes and extinction.

Keystone Niche Pollination Regulation/control population Remove, Bury, Recycle (dung it anyway!) Biopharming

Foundation Species: Create and enhance habitat in ways that benefit others Trimming Trees Rolling over rocks Tearing trees out by roots Planting

6.3 Species Interactions Key Concept: Increase ability to survive through Competition and Symbiotic Relationships

Competition Interspecific Competition Abundant Resources personify fundamental niche Non abundant causes a more realized niche Humans deprive species of resources causing more realized niches occupation Interspecific Competition

Can we Reduce or Avoid Competition? Competition allows for 1.Adaptations through Natural Selection 2.Predator/Prey Relationship Prey on the least fit 3.Keeps populations in check not to exceed resources

How do predators increase their chances of catching prey? Lie in wait Persue Camoflage

Can Prey Defend Themselves? Escape Pretective shells Camoflage Mimicry Chemicals

Parasites Sponge Off Each Other Parasite (sponger) Host (spongee)

Other symbiotic relationships Mutualistic: Commensalistic: Parasitic Both benefit ++ One benefits other is neither harmed or benefits +0 One benefits the other is harmed +-

6.4 Ecological Succession Change of Producers mass Over Time Terrestrial Succession

Aquatic Succession

Succession PRIMARY Gradual establishment of biotic communities on newly exposed rock No soil, No bottom sediment Receding ice bergs New Lava Flows SECONDARY On existing soil, or bottom sediment Reestablishment of any Cleared area due to Fires, tornados, tsunamis, human impact

Is this primary or secondary succession?

From Pioneer Species to Intermediate Species, to a Climax Community Primary: initial, does not need much soil or water Intermediate species: need some soil, water, sun Climax community: needs more soil and other factors

Can we Predict Succession? Not Always An ever changing mosaic of vegetation patches On going struggle by species for resources Climax Community: Mature community for that climate

6.5 Population Dynamics and Carrying Capacity Enter: Births, immigration, and decrease in deaths Exit: Death, emigration

© 2004 Brooks/Cole – Thomson Learning Figure 9-4 Page 193 © 2004 Brooks/Cole – Thomson Learning K Population size (N) Population size (N) Time (t) Time (t) Exponential Growth is J shaped: rarely keeps going Logistic Growth: levels off is S shaped. Growth is never just exponential only – it reaches carrying capacity and levels off

Overshoot of Carrying Capacity Occurs when births are greater than deaths Humans not exempt Then causes a ‘dieback’ or ‘crash’ Polynesians on Easter Island

Carrying Capacity is ecosystems maximum ability to support populations Carrying Capacity is ecosystems maximum ability to support populations. Directly related to producer biomass and climate

Exponential vs. Logistical Growth Curves Lag Phase—First portion of the curve; slow population growth. Exponential Growth Phase—More organisms reproducing causing accelerated growth; continues as long as birth rate exceeds death rate. Stable Equilibrium Phase—Death rate and birth rate equilibrate; population stops growing; achieved in logistical growth curves

Population Growth Curve

Reproductive Patterns R and K Strategies Some species have few offspring and take care of them until they care for themselves K Selected Species ( K = competitor) Some have many and care-less R-selected species (R means Rapid)

Reproductive Strategies and Population Fluctuations Not all species reach a stable carrying capacity. Species can be broadly lumped into two categories: K- strategists- competitor species; they do well in competitive situations where population size is close to or at carrying capacity; logistical growth R-strategists- have a high intrinsic rate (r) of increase; exponential “boom & bust” cycles of growth

Reproductive Strategies Which one has a greater Range of Tolerance? K-selected: mature slowly have few offspring at a time most endangered species are K-selected population stabilizes near carrying capacity maintain numbers in stable ecosystems Do well in competitive conditions Specialist Niche Late Succession dwellers High ability to compete Livestock Mammals r-selected: mature rapidly have many offspring - tend to overproduce  Die before reach maturity  population not regulated by density  opportunistic -- invade new areas Generalist Niche Early Succession dwellers low ability to compete opportunists Crops Algael Bacteria Depends on the available habitat determines success!

6.6 Human Impact on Ecosystems Where Natural Systems would allow re-growth, reuse,recycling, and be renewable…Man doesn’t and is less forgiving ,simplifying biodiversity, Using up non-renewable energy, producing much waste, wastes rather than recycles and uses, destroys, or degrades Net Productivity Ie: (doesn’t share with others well)

Principles of Sustainability Follow Nature - Four Ways Nutrient Cycling -Renewable Resources Especially Energy and waste Solar Energy Use Biodiversity to maintain itself and adapt Control population size and resource use