1. AP Environmental Science Community Processes: Species Interactions and Succession Ch 8 Miller 12 th Ed. © Brooks/Cole Publishing Company / ITP

2. Outline 1. The Ecological Niche roles, fundamental and realized niche, generalists vs. specialists 2. Some General Types of Species native, non–native, indicator, and keystone species 3. Types of Species Interactions 4. Symbiotic Species Interactions parasitism, mutualism, and commensalism 5. Succession primary and secondary succession 6. Island Biogeography 7. Stability and Sustainability © Brooks/Cole Publishing Company / ITP

3. 1. 1. The Ecological Niche © Brooks/Cole Publishing Company / ITP Niche: the role that an organism plays in an ecosystem. Defined by the range of conditions and resources within which an organism can live Conditions: physical attributes of the environment, though not consumed, that influence biological processes and population growth, e.g., temperature, salinity, acidity Resources: substances or parts of the environment used and consumed or otherwise made unavailable to other organisms, e.g., food, water, and nesting sites for animals; water, nutrients, and solar radiation for plants; Contrast with habitat, the actual place an organism lives.

4. Generalists vs. Specialists © Brooks/Cole Publishing Company / ITP Generalists have broad niches, whereas specialists have narrow niches: Generalists: Cockroaches, coyotes, dandelions, humans Have advantage when environmental conditions change Eat wide variety of food and tolerate wide range of conditions: VERY ADAPTABLE Specialists: Spotted owls require old–growth forests, giant pandas eat primarily bamboo in bamboo forests of China Have advantage when environmental conditions are more constant. Prone to extinction due to many limiting resources.

5. Fundamental vs. Realized Niche © Brooks/Cole Publishing Company / ITP Fundamental niche: full range of conditions and resources that an organism could theoretically use in the absence of competition with other species. Realized niche: portion of the fundamental niche that an organism actually occupies; actual range of conditions and resources that an organism uses. Niche overlap between species leads to competition

6. Community  Three characteristics to describe a biological community –1. Physical appearance  Size, stratification, and distribution  Transitional edges between communities can cause variance of community—increased edge area = increased vulnerability –2. Species diversity  Combination of # of different species (richness) and the # of individuals within each species (evenness)  Affected by latitude, pollution, habitat diversity, NPP, etc.  Tropical rainforest at equator (low latitude) most diverse –3. Niche structure  The number of niches and variety and species interaction with one another

7. 2. Some General Types of Species © Brooks/Cole Publishing Company / ITP Native species: species that normally live and thrive in a particular ecosystem: Nonnative species (also called exotic species or alien species) originate in other ecosystems May enter an ecosystem by migration or by deliberate or accidental introduction by humans Example: "killer bees", wild bees from Africa were imported to Brazil to increase honey production, but displaced native bees, decreased honey production, spread. Newly arrived nonnative species usually not able to survive, but when they take hold they can be invasive.

8. Invasive species- special type of nonnative species which aggressively establishes itself in the community to the possible detriment of other plants and animals in the area (can outcompete native species, reproduce rapidly, and alter biodiversity) Kudzu—from Asia--covers, smothers, and kills plants that it covers (can grow up to 1 foot per day!) Cane Toads—introduced into Australia to control sugar cane pests; toads have poison glands and poisoned native species that ate them

9. Some General Types of Species © Brooks/Cole Publishing Company / ITP Indicator species: species that serve as early warnings that a community or ecosystem is being damaged: Example: decline of migratory songbirds in North America indicates loss and fragmentation of habitat in meso-America and South America Example: presence of trout in mountain streams is an indicator of good water quality Example: spotted owls are indicator of healthy old–growth forest. Example: amphibians are especially vulnerable to environmental disruption at several stages in their lives

10. Figure 8-6 Page 147 sperm Eggs Sexual reproduction Fertilized egg development Organ formation Egg hatches Tadpole develops Into frog Young frog Adult frog (3 years) Frogs serve as indicator species because different parts of their life cycles can be easily disturbed.

11. Some General Types of Species © Brooks/Cole Publishing Company / ITP Keystone species: species that play a critical role in an ecosystem Example: sea otters because they prevent sea urchins from depleting kelp beds Example: dung beetles because they remove, bury and recycle animal waste Example: beavers are because they build dams and create habitat for a diverse community of species (bluegill fish, muskrats, herons, ducks…).

12. Some General Types of Species Foundation species: can create and enhance habitats that can benefit other species in a community  Elephants in the savannas uprooting trees benefits growing grasses, smaller grazing species, accelerates nutrient cycling  Bats and birds can distribute seeds in waste, regenerating deforested areas.

13. 3. Types of Species Interactions © Brooks/Cole Publishing Company / ITP Major types of biotic interactions: Interspecific competition: 2 or more species use same limited resources so fundamental niche overlap. Example: fire ants are better competitors than native species of North America and sharply reduce their populations up to 90% Example: humans and many other species Resource partitioning— species competing for similar scarce resources evolve more specialized traits that allow them to use shared resources at different times, in different ways, or in different places

14. Resource Partitioning © Brooks/Cole Publishing Company / ITP Species with similar resource needs can coexist because they use limited resources at different times, in different ways, or in different places. Example, specialized feeding niches of various birds of coastal wetlands enable coexistence of many species. Fig. 9–4a

15. Resource Partitioning © Brooks/Cole Publishing Company / ITP Fig. 9–5 Five species of insect–eating warblers are able to coexist in spruce forest of Maine. Each species minimizes competition with others for food by spending majority of feeding time in a distinct portion of spruce trees (shaded areas) Each also consumes somewhat different insect species.

16. Resource Partitioning © Brooks/Cole Publishing Company / ITP Fig. 9–5 (continued)

17. Character Displacement © Brooks/Cole Publishing Company / ITP Over many years coexisting species tend to evolve physical and behavioral adaptations to minimize competition. Example: Darwin's finches on the same island have evolved different bill sizes and eat different size prey. Fig. 9–6.

18. Principle of Competitive Exclusion © Brooks/Cole Publishing Company / ITP G.P. Gausse, in a classical experiment (1934), showed that two species with identical niches can not coexist indefinitely. This is called the principle of competitive exclusion. Fig. 9–3

19. Niche Specialization  Niches become separated to avoid competition for resources. Figure 7-6

20. Types of Species Interactions –Predation: members of one species (predator) feed on another species (prey)  Example: lion feeding on zebra  At the population level, predation plays a role in evolution by natural selection  Predators often kill the sick, weak, least fit members of a population  Helps successful genetic traits to become more dominant in the prey population

21. Predation © Brooks/Cole Publishing Company / ITP Predators tend to evolve characteristics for efficient capture of prey (keen eyesight, speed, etc.). Prey tend to evolve characteristics to avoid being eaten (camouflage, chemical defenses, behaviors that startle predators, behaviors that mimic dangerous species (Batesian mimicry), keen sense of smell, etc.).

22. Camouflage—when an animal blends in with its environment The Peppered Moth

23. Countershading- form of camouflage where the animal is darker on top and lighter on the bottom to blend in with shadows Ibexes countershade against a desert background

24. Fig. 7-8a, p. 153 Spanworm (masquerading) Masquerading —when a species disguises itself to look like an inanimate object

25. Fig. 7-8b, p. 153 Wandering leaf insect (masquerading)

26. Fig. 7-8c, p. 153 Bombardier beetle—they emit hot noxious chemical spray from their abdomen (chemical warfare)

27. Fig. 7-8e, p. 153 Poison dart frog (chemical warfare)

28. Fig. 7-8d, p. 153 Foul-tasting monarch butterfly (chemical warfare)

29. Fig. 7-8g, p. 153 Hind wings of Io moth resemble eyes of a much larger animal (mimicry)

30. Fig. 7-8h, p. 153 When touched, snake caterpillar changes shape to look like head of snake. (mimicry)

31. Batesian Mimicry—a harmless species mimics the coloration of an undesirable (dangerous/foul tasting) species The viceroy butterfly at the top appears similar to the foul-tasting monarch butterfly, therefore predators are hesitant to eat the viceroy

32. Types of Species Interactions © Brooks/Cole Publishing Company / ITP Major types of biotic interactions (cont’d): Symbiosis: a long–lasting relationship in which species live together in intimate association: -Parasitism: one organism (parasite) lives on part of another organism (host) -Mutualism: two species interacting in a way that benefits both -Commensalism: one organism benefits from another, but neither helps nor harms the other organism

33. 4. Symbiotic Species Interactions © Brooks/Cole Publishing Company / ITP Parasitism can be viewed as a special type of predation wherein the parasite: 1) is usually smaller than the prey 2) remains closely associated with the prey over time, and 3) rarely kills its host Endoparasites live inside their host, e.g., tapeworm living in the gut; Plasmodium living inside a vertebrate and causing malaria. Ectoparasites live outside their host, e.g., mosquito feeding on the blood of mammal; lamprey attaching to outside of a host fish

34. Close your eyes if you don’t want to see a picture of a tapeworm in a gut…

35. Ectoparasites: Tapeworms in the guts of host

36. Mutualism © Brooks/Cole Publishing Company / ITP Mutualism: relationship in which both interacting species benefit. Obligatory mutualism results when two organisms cannot live without each other; cannot live apart Example: in lichens an algae provides photosynthesis and a fungi provides a home for the algae Example: Rhizobium bacteria, in legume plant root nodules, fix nitrogen and legume provides carbohydrates and home Example: termites have gut organism that can digest cellulose Facultative mutualism: the organisms can live apart, but there is strong mutual benefit in the relationship Example: flowering plants and their pollinators, plant gets pollinated, pollinator gets nectar or pollen to eat

37. Mutualism © Brooks/Cole Publishing Company / ITP There are many more classic examples of mutualism. Oxpecker bird (“tickbird”) feeds on the parasitic ticks of various large mammals in Africa, such as the black rhinoceros (facultative mutualism) Mycorrhizal fungi live in the roots of various plants; the fungus gets carbohydrates and the plant gets better absorption of nutrients by the fungal mat that extends beyond the roots (obligative mutualism) Clownfish in the coral reefs of Australia; clownfish gains protection from stinging tentacles and food when the anemone feeds; the anemone gains protection from various fish that feed on sea anemones (facultative mutualism)

38. Fig. 7-9c, p. 154 Mycorrhizal fungi on juniper seedlings in normal soil

39. Fig. 7-9d, p. 154 Lack of mycorrhizal fungi on juniper seedlings in sterilized soil

40. Commensalism © Brooks/Cole Publishing Company / ITP Commensalism: relationship in which one species benefits while another is neither helped not harmed to a significant degree. Redwood sorrel, a small herbaceous plant, benefits from growing in the shade of tall redwoods, but the redwoods are not affected; Mosses growing on tree trunks (mosses receive anchorage and shade, while tree is unaffected) Epiphytes (orchids and bromeliads) grow in trees in the tropical rain forest gain a favorable place to live; whereas the tree is not affected **If epiphytes become abundant to block light, the tree can be negatively affected, and this becomes an example of competition. Epiphyte

41. Redwood sorrel at the base of Redwood trees

42. 5. Succession © Brooks/Cole Publishing Company / ITP Succession: gradual and fairly predictable change in species composition with time. Some species colonize and become more abundant; Other species decline or even disappear. Two kinds of succession: Primary succession: gradual establishment of biotic communities in an area where no life existed before  NO SOIL! Secondary succession: gradual reestablishment of biotic communities in an area where a biotic community was previously present  SOIL ALREADY ESTABLISHED

43. Primary Succession © Brooks/Cole Publishing Company / ITP Primary succession occurs with time in lifeless areas. Newly formed islands, post-volcano, post-glacier, post-sand dune Early successional species: typically lichens and mosses first colonize bare rock--the first species to colonize are termed pioneer species (overall low species and plant diversity) Mid: later small herbs and shrubs colonize Late: finally tree species colonize Takes lots of time  1 inch of soil can take 200-1000 yrs. to form.

44. Primary Succession © Brooks/Cole Publishing Company / ITP Primary succession over several hundred years on bare rock exposed by a retreating glacier on Isle Royal in northern Lake Superior. Fig. 9–19

45. Primary Succession on a Sand Dune  Grasses—grasses hold down the sand to allow more complex roots/shrubs to develop  Shrubs/Alders/Willows  Sun-requiring trees (cottonwoods, spruce)  Larger sun-requiring trees (pines, black oaks, aspen, birch)  With larger trees providing shade, trees tolerant of shade grow (beech, maple, ash, hemlock, tulip trees, etc.)  Saplings from the pines, black oaks, aspen, and birch cannot proliferate with the shade, so those species die out, and the vegetation is dominated by the beech, maple, ash, hemlock, etc.

46. Primary Succession © Brooks/Cole Publishing Company / ITP Greatly simplified view of primary succession in a newly created pond in a temperate area. Nutrient rich bottom sediment is shown in dark brown. Fig. 9–20a

47. Secondary Succession © Brooks/Cole Publishing Company / ITP Secondary succession occurs where the natural community of organisms has been disturbed, removed, or destroyed. (post-fire, abandoned agricultural field) Agricultural fields go through succession. Succession proceeds until an area is occupied by a climax community, however recent views recognize that a single climax is not predictable. Not as lengthy process as primary due to existence of soil.

48. Secondary Succession © Brooks/Cole Publishing Company / ITP Fig. 9–21 Secondary succession over 150–200 years in an abandoned farm field in North Carolina. (soil is already present, so no need for pioneer species)

49. An example of Secondary Succession by stages: 1. A stable deciduous forest community 2. A disturbance, such as a wild fire, destroys the forest 3. The fire burns the forest to the ground 4. The fire leaves behind empty, but not destroyed, soil 5. Grasses and other herbaceous plants grow back first 6. Small bushes and trees begin to colonize the area 7. Fast growing evergreen trees develop to their fullest, while shade- tolerant trees develop in the understory 8. The short-lived and shade intolerant evergreen trees die as the larger deciduous trees overtop them. The ecosystem is now back to a similar state to where it began.

50. Secondary Succession © Brooks/Cole Publishing Company / ITP Successional changes in the animal community accompany successional changes in the plant community. Fig. 9–22

51. Table 8-1 Page 158 Table 8-1 Ecosystem Characteristics at Immature and Mature Stages of Ecological Succession Characteristic Ecosystem Structure Plant size Species diversity Trophic structure Ecological niches Community organization (number of interconnecting links) Ecosystem Function Biomass Net primary productivity Food chains and webs Efficiency of nutrient recycling Efficiency of energy use Immature Ecosystem (Early Successional Stage) Small Low Mostly producers, few decomposers Few, mostly generalized Low High Simple, mostly plant herbivore with few decomposers Low Mature Ecosystem (Late Successional Stage) Large High Mixture of producers, consumers, and decomposers Many, mostly specialized High Low Complex, dominated by decomposers High

52. Disturbance © Brooks/Cole Publishing Company / ITP What is the role of disturbance in succession? Disturbance: a discrete event that disrupts an ecosystem or community Fires, hurricanes, tornadoes, droughts and floods Human–caused disturbance: deforestation, overgrazing, plowing Initiates secondary succession by eliminating part or all of the existing community, and by changing conditions and releasing resources.

53. Mechanisms of Succession © Brooks/Cole Publishing Company / ITP Both primary and secondary succession are driven by three mechanisms: Facilitation: a process by which an earlier successional species makes the environment suitable for later successional species; e.g., legumes fixing nitrogen can enable later successional species. Inhibition: a process whereby one species hinders the establishment and growth of other species; e.g., shade of late successional trees inhibits the growth of early successional trees; Tolerance: a process whereby later successional species are unaffected by earlier successional species.

54. Changes During Succession © Brooks/Cole Publishing Company / ITP During succession species diversity and stratification tend to increase, while growth rates and primary productivity tend to decrease. **See Table 8-1 Fig. 9–23

55. 6. Island Biogeography © Brooks/Cole Publishing Company / ITP In the species equilibrium model of island biogeography (developed by Robert MacArthur and Edward O. Wilson) the number of species on an island is determined by the balance between immigration and extinction. Fig. 9–24

56. Island Biogeography © Brooks/Cole Publishing Company / ITP Small islands are expected to have lower immigration rates and higher extinction rates, and hence fewer species than large islands. Fig. 9–24

57. Island Biogeography © Brooks/Cole Publishing Company / ITP Far islands are expected to have lower immigration rates, and hence fewer species than near islands. Fig. 9–24

58. Case Study: Hawaii  Pre-human Hawaii had great native biodiversity before Polynesian seafarers arrived around A.D. 400. Today it is “synthetic.”  Island biogeography dictates that these islands far from the mainland would have very little possibility of species naturally immigrating. Humans did. WE were an invasive, nonnative species 1500 years ago.  The islands have been further overrun by nonnative species we carried, introduced accidentally or intentionally. It was a popular stopover in Pacific travels. –Of the original 145 endemic birds only 35 remain, 24 of which are endangered –Of the 1900 flowering plant species today, over 900 are alien and are dominating over the rest –Of the 8800 insect and arthropod species, over 3000 are of alien origin –Ants, the leading predators of insects, never used to inhabit Hawaii, but are now wreaking havoc on their insect populations –Feral pigs, not on the island until they were brought by humans, are also causing huge problems with destroying vegetation.

59. Island Biogeography © Brooks/Cole Publishing Company / ITP The model of island biogeography has been widely applied in conservation biology by viewing the landscape as composed of habitat islands separated by an ocean of degraded or unsuitable habitat modified by human activity. Large habitat patches tend to have more species Habitat patches that are near larger intact habitat areas tend to have more species These principles can be applied to land preservation and management efforts.

60. 7. Stability and Sustainability © Brooks/Cole Publishing Company / ITP Stability has three aspects: Inertia (or persistence): the ability of a system to resist being disturbed or altered Constancy: the ability of a living system to maintain a certain size or state Resilience: the ability of a living system to recover after a disturbance

61. Stability and Sustainability  Signs of poor health or stressed ecosystems: –Decrease in primary productivity –Increased nutrient losses –Decline or extinction of indicator species –Increased populations of pests or disease organisms; –Decline in species diversity –Presence of contaminants.  Through an understanding of ecology we can grapple with what it means to have sustainable ecosystems.