Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Storage effect wikipedia , lookup
Ecological fitting wikipedia , lookup
Habitat conservation wikipedia , lookup
Latitudinal gradients in species diversity wikipedia , lookup
Occupancy–abundance relationship wikipedia , lookup
Biodiversity action plan wikipedia , lookup
Introduced species wikipedia , lookup
Theoretical ecology wikipedia , lookup
Island restoration wikipedia , lookup
Community Ecology: Structure, Species Interactions, Succession, and Sustainability Other labels for species • • • • Native Non-native Indicator keystone Native vs. nonnative species • The species that naturally/normally live and thrive in a particular area are called native species • A species that migrates into, or is accidentally or intentionally introduced into an ecosystem is a nonnative species • How do these species arrive to their new destination? • Nonnative = exotic = alien= invasive Nonnative nightmares! • • • • • • • Zebra mussels Cane toads African bees (killer bees) Eurasian watermillfoil Snakehead fish Ginko trees Purple loosestrife Why are exotic species intentionally brought/introduced to a new area? Why is this bad? • INVASIVE and HIGHLY PROLIFIC! Indicator species • Species that serve as early warnings that a community or ecosystem may be at risk or being damaged are called indicator species • They are very sensitive to environmental changes • “Many species don’t need us, but we and other species need them.” Some additional info. • • • • • Bioindicators indicator sp. coyotes as indic. sp. lichens as bioindicators surfers as ind. sp. Examples of indicator species • • • • • Most stream macro-invertebrates Birds Trout Lichens amphibians Keystone species • A species whose role in an ecosystem are much more important than their numbers or biomass would indicate are called keystone species • Often linked to a large number of other species • Play critical role in the structure, function, and integrity of an ecosystem. • They are the link to many other species! More of what they do… • Process material out of proportion to their #’s or biomass Examples of keystone species • Bees, bats, hummingbirds, ants for pollinating and seed dispersal • Dung beetles for removal, burial, and recycling of waste • Sea otters for eating sea urchins which destroy kelp beds • American alligator, wolf, lion, great white shark for keeping prey pop.’s in check • Beavers for modifying habitat from streams/rivers into ponds/lakes EXAMPLES: • Keystone species • another keystone species Edward O. Wilson says…. • “The loss of a keystone species is like a drill accidentally striking a power line. It causes lights to go out all over.” Species interactions • Intraspecific competition – same sp. Competing for resc. • Interspecific competition – different sp. Competing for resc. • Predation • Symbiosis (mutualism, commensalism, parasitism) Intraspecific compet. • SAME sp. Compete – Through territoriality • Sp. Mark their home, nesting or feeding site • Defend it against members of own sp. Interspecific competion • When two or more different species compete for limited resources – LIMITED RESOURCES =space, matter, water, food, sunlight, nesting sites, hiding spots, etc. • Those involved are harmed to varying degrees depending on which is the best competitor • If resc. Are abundant...sp. get closer to occupying their fundamental niche BUT if not…parts of their fundamental niches overlap = COMPET.! When fundamental niches overlap… • • • • 1 sp. May be forced to migrate Change eating habits Dec. in pop. Via nat. sel. Extinction may occur Types of Interspecific • • • • Interference competition Exploitation competition Competitive exclusion Competitive exclusion principle Interference competition • One species may limit another’s access to resources • Behaviors include: – – – – establishment and defense of territory Chemical secretions, poisoning Bird calls to mark territory Sp. ACTIVELY INTERFERE with other sp. Access to the limited resc. Exploitative competition • Competing species attempt to exploit their “fitness” over the competition by using their adaptations (reproductive success vs. strength) • For example: – Faster – Stronger – Better vision • So one species gets more of a resource and this limits the growth, reproduction, and survival of the competing species • Species EXPLOIT their best trait! The competitive exclusion principle • One niche, one species, one place – This is why one sp. Is excluded • No two species can occupy the same niche at the same time, indefinitely if there is not enough of a resource • 1 sp. eliminates another sp. In an area via competition for a limited resource. • See research using paramecium Ways to avoid competition.. • Resource partitioning = same habitat…different niche • USE REALIZED NICHE!!!! – warblers Resource partitioning • Dividing up scarce resources so that species with similar requirements can use them at different times, or in different ways, or in different places • Examples: – Wetlands – Warblers in Spruce trees Character displacement • Happens through evolution • When similar species in an area develop slightly differing traits or characteristics (including behavioral) that allow them to use different resources • Examples: – Bills of birds – Tortoise shells Predation • Members of one species feed directly on all or part of a living organism of another species • The predator benefits and the prey is harmed (but does not have to be killed) Predator-prey relationships • • • • Carnivores Herbivores Prey does not have to be killed We are direct and indirect predators Pros and cons… • Although a single animal may be harmed, predators actually HELP prey species by killing the sick, weak, and aged members – This limits competition for resources among prey – And may improve gene pool for species Predatory behaviors… • Pursuit • Ambush Prey behaviors…. • • • • • • Camouflage Warning coloration Mimicry Chemical warfare Protective shells Limbs that break off Symbiosis • Is a long-lasting relationship in which organisms live together intimately • Three types of symbiotic relationships are – Parasitism – Mutualism – commensalism Parasitism • Parasites – – – – – Live in or on host Usually smaller than host Draws nourishment from host Gradually weakens host Rarely kills host Types of parasites…. • Endoparasites- live INSIDE host – Tapeworms, parasitic wasps, plasmodium • Ectoparasites – attach to OUTIDE/ ON host – Lice, ticks, mosquitos, athlete’s foot fungus, lampreys Mutualism • Win-win relationship • Pollination relationship between plants and insects • Nutritional relationships – Lichens (algae and fungus) – Termites and protozoans (home/digest wood) – Rhizobium bacteria and legumes (N conv./sugar) More mutualism • Protective mutualism – Birds and elephants and Rhinos – Stinging ants and acacia trees Commensalism • One species benefits while the other is neither helped nor harmed • Some examples are: – Epiphytes (orchids and bromeliads) – Barnacles on whales Ecological succession • Ecologists describe ecosystems by: – – – – Physical appearance Niche structure Species diversity Species abundance Ecosystems change • Ecosystems change in response to changing environmental conditions • Succession can happen gradually or rapidly depending on environmental conditions Primary succession • The development of communities in a lifeless area with no soil or bottom sediment • Such places might be barren rock, newly cooled lava flow, abandoned highway, boulders/exposed bedrock from retreating glaciers • Primary succession begins with pioneer species – Lichens and mosses are pioneer organisms • They trap soil particles • Lichens secrete acids breaking down the rock • FORMING SOIL! Successional species • Pioneers • Early successional plant species – Grasses, herbs, ferns • Midsuccessional plant species – Grasses, shrubs • Late successional plant species – Trees – Ends in a stable and complex forest Secondary succession • Begins in an area whose natural vegetation has been removed, disturbed, destroyed • Abandoned farms, cut forests, burned forests • Ends in a stable and complex forest Pond succession • Occurs in ponds, lakes, streams Animal succession? • Ecological succession focuses on changes in vegetation • But as plant succession proceeds, the numbers and types of animals changes with it • Different wildlife can be found at different successional stages in each ecosystem • At each stage of succession, species diversity, trophic structure, niches, nutrient cycling and energy flow changes! Factors affecting the rate of succession • Facilitation – 1 sp. modifies the env. and makes an area suitable for sp. with different niche requirements to survive • Inhibition – early sp. hinder the establishment and growth of another sp. (emit toxins) • Tolerance – late successional sp. aren’t affected by plants of earlier stages of succ. The role of disturbances in succession • • • • • • • • Human caused vs. natural Catastrophic vs. gradual Flood Fire Groundwater depletion Waterlogging soils Pesticide application Pollution Intermediate Disturbance Hypothesis • Communities that experience fairly frequent, moderate disturbances have the greatest diversity of species Climax communities • All succession ends theoretically with a climax community being established – Stable and complex ecosystem of long-lived tree species