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You’re welcome to linger in these woods. Water sustains the entire Monongahela ecosystem. ECOLOGICAL SUCCESSION • • • • • • PROCESS OF CHANGE OVER TIME DIRECTIONAL PREDICTABLE END-POINT = CLIMAX STAGE CLIMAX = STABLE, SELFPERPETUATING COMMUNITY An autumnal umbrella arches above the 41-year-old forest stand. Where it all ends up: Creeks in the Fernow Experimental Forest feed the glistening Cheat River. SUCCESSION CONCEPT • IMPLIES SEQUENCE OF NEW SPECIES OVER TIME • MUST GET THERE--SOME FORM OF DISPERSAL – OVERCOME BARRIERS (LIST SEVERAL) • COMPLETE LIFE CYCLE • EFFECTIVELY REPODUCE/COMPETE 1 TYPES OF SUCCESSION • NON-DIRECTIONAL – CYCLIC--REPEATED SEQUENCE • DIRECTIONAL – PRIMARY SUCCESSION • BARREN HABITAT (VOLCANIC ISLAND; GLACIAL DEBRIS, ABANDONDED GRAVEL PIT; NEWLY CREATED POND/LAKE) – PIONEER SPECIES • OPPORTUNISTIC COLONIZERS PRIMARY SUCCESSION • PRIMARY COLONIZERS • MODIFY ENVIRONMENT TO ALLOW FOR OTHER SPECIES TO BE BETTER ABLE TO COMPETE/ESTABLISH THEIR PRESENCE AT SITE – NEW SPECIES OUT-COMPETE PRIMARY COLONIZERS – RESULTS IN CHANGE IN COMMUNITY – CHANGE IN SPECIES COMPOSITION PRIMARY SUCCESSION • PRIMARY COLONIZERS--FIRST ONE(s) THERE – CHARACTERISTICS • GOOD COMPETITORS • REPRODUCE MANY OFFSPRING • (r-SELECTIVE) • SEVERAL (MANY) REPR. CYCLES/YEAR • SMALL BODY SIZE PRIMARY SUCCESSION • PROCESS OF SEQUENTIAL CHANGE • TAKES PLACE OVER TIME • STAGES IDENTIFIED: SERES (SERAL STAGES) – OLD FIELD – SHRUB – FOREST • PINE, OAK-HICKORY, BEACH-MAPLE 2 PRIMARY SUCCESSION OAK-HICKORY FOREST @ LOESSEL BOG, EASTERN MICHIGAN UNIVERSITY--1964 BEECH-MAPLE WOODLOT--CURTISS ROAD, YPSILANTI, MI ca. FALL, 1964 CONTIGUOUS QUADRAT SAMPLING: OLD FIELD PRIMARY SUCCESSION @ U of M BOTANICAL GARDENS, JOHN DIX FIELD, ca 1966 (with Wm. S. BENNINGHOFF) BEECH-MAPLE WOODLOT--CURTISS ROAD, YPSILANTI, MI ca. FALL, 1964 VIRGIN BEECH-MAPLE FOREST, PAOLIA, IN (FALL 1970) 3 SECONDARY SUCCESSION VIRGIN BEECH-MAPLE FOREST, PAOLIA, IN (FALL 1970) • SIMILAR SEQUENCE AS PRIMARY; STARTING POINT DIFFERENT – SITE PREVIOUSLY OCCUPIED BY ORGANISMS: ABANDONED FARMLAND RESULTING IN OLD FIELD---FOREST – SOME TYPE OF SOIL STRUCTURE PRESENT • FARMING, LOGGING, FIRE, WINDS – DISTURBANCE LEAVING SOME SOIL/OTHER ORGANISMS SECONDARY SUCCESSION OAK TUBES: Plastic tubes protect oak seedlings from grazing deer, whose numbers are unusually high due to population declines among their natural predators: mountain lions and coyotes. Oaks are prized as timber and for the diversity of wildlife they support, but their numbers are dwindling in the forests of the eastern United States. Their decline is a mystery to rangers and scientists. This forest stand was cut two years ago. Site1/view2 Site 1/view1 FOREST FLOOR: Birds, bears, and other animals carried seeds to this spot. The seeds lay dormant on the ground Site 1/ awaiting an opening in the canopy to admit daylight. view3 Clearing the plot provided that opening. Now blackberries, grapevines, and wildflowers spring up amid a sea of new green life. Animals will eat the fruit and renew the cycle. 4 STUMP: Without direct sunlight to dry them, stumps in this plot remain damp through most of the year. The moisture Site 2/ view1 hastens their decay. Mosses, among the most primitive plants, thrive on the rotting wood. So do fungi such as mushrooms, which spread by spores borne on the wind or via tendrils beneath the ground. FOREST FLOOR: Except for patches of moss, almost nothing green survives on the ground. It is brown and mottled with fallen leaves. As they deepen and decompose, they mix with minerals from the weathered bedrock below to create a rich organic soil. Site 2/ view 3 This forest stand was cut 41 years ago. Site 3/ view 2 This forest stand was cut 12 years ago. Site 2/ view 2 DEBRIS: Some trees, such as the fire cherry (which rarely survives more than 40 years), have run their course and toppled. The dead trunks of this tree litter the ground. Here too are snags—standing trunks of dead trees. They draw woodpeckers, which feast on the insects within them. Squirrels and owls sometimes nest inside hollow snags. Site 3/ view 1 TREES: Shade-tolerant beeches and sugar maples subsist in the understory (above the ground but below the treetops) on what light can reach them. The tallest survivors—rising to heights of 90 feet (27 meters)—include hickories, red maples, and yellow poplars. But no oaks. Sizable trees number 600 per acre (1,500 per hectare). Site 3/ view 3 5 This forest stand was cut about 86 years ago. REBIRTH: No forest is ever finished. Even amid elderly sentinals new plants grace the forest floor. For nature, wrote Gerard Manley Hopkins, “is never spent.” Site 4/ view 3 Site 4/ view 2 CLIMAX COMMUNITY • STABLE TREES: Vestigial oaks, the great providers of the eastern forest, remain here in the oldest plot. Each supports hundreds of other plant and animal species in microhabitats within the limbs, along the trunk, inside the leaves, and among the roots. These mature woods are home to about 125 large trees per acre (310 per hectare). – SELF-PERPETUATING (REGENERATING) – SPECIES ASSEMBLAGE IN EQUILIBRIUM WITH ENVIRONMENT (BIOTIC/ABIOTIC) – IN “HARMONY” WITH REGIONAL CLIMATE AND SOIL TYPES • CLIMAX PATTERN HYPOTHESIS Site 4/ view 1 PIONEER COMMUNITY VS. CLIMAX COMMUNITY • SEQUENCE OF SUCCESSION--MARKED BY STAGES CALLED SERES – SERAL STAGES • OLD FIELD • SHRUB • FOREST • EXAMINE & COMPARE VARIOUS CHARACTERISTICS OF TWO ENDS OF SPECTRUM (PIONEER VS. CLIMAX) – COMMUNITY ADAPTED TO TOTAL PATTERN OF ENVIR. FACTORS PIONEER COMMUNITY • OPPORTUNISTIC SPECIES – PRIMARY COLONIZERS • EASILY OVERCOME DISPERSAL BARRIERS – DIFFUSION DISPERSAL – JUMP DISPERSAL (LARGE BARRIERS_ • MOUNTAIN RANGES, DESERTS, OCEANS 6 PIONEER COMMUNITY (CONT’D) • • • • SMALL BODY SIZE MANY OFFSPRING PER GENERATION MANY GENERATIONS/YEAR/SEASON INTENSE COMPETITION – SIGNIFICANT NICHE OVERLAP • LOW SPECIES DIVERSITY – FEW SPECIES; MANY INDIVIDUALS • r-SELECTIVE SPECIES CLIMAX COMMUNITY (CONT’D) • MULTIPLE ENVIRONMENTAL FACTORS DEFINE SIZE & SHAPE OF NICHE FOR A SPECIES • SPECIES ADAPTATIONS HELP DEFINE NICHE SPACE • NICHE SPACE OF ONE SPECIES MAY OVERLAP WITH ANOTHER CLIMAX COMMUNITY • END-POINT = CLIMAX • STABLE • HIGH SPECIES DIVERSITY – MANY SPECIES • • • • • • LOW COMPETITIVE INTERACTION LIMITED NICHE OVERLAP LARGE BODY SIZE FEW OFFSPRING PER GENERATION “ONE” REPRODUCTIVE CYCLE PER YEAR K-SELECTIVE SPECIES SPECIES DIVERSITY (DEFINITION) • TOTAL NUMBER OF SPECIES IN A GIVEN AREA (PER UNIT AREA) – INTERACTION (COMPETITION) SPECIES DIVERSITY: (USES & APPLICATIONS) • SPECIES DIVERSITY – UNIQUE CHARACTERISTIC OF COMMUNITY OR ECOSYSTEM – QUANTIFIED ATTRIBUTE – MEASURE OF COMPLEXITY AND STABILITY OF HABITAT/ECOSYSTEM – PRACTICAL USE: INDEX AS TO SEVERITY OF POLLUTION 7 GEOGRAPHIC PATTERNS: NOT ALL COMMUNITIES SAME • NORTH-SOUTH LATITUDINAL GRADIENTS –TERRESTRIAL –AQUATIC • FRESH WATER SYSTEMS • OCEANS • TOPOGRAPHIC RELIEF –ALTITUDINAL TRENDS –MNT. SYSTEMS-ROCKIES/APPALACHIANS HAVE GREATER NUMBER THAN AVE. MAMMALS LAVA FLOW COOLING LAVA AFTER ERUPTION VOLCANIC ISLAND 8 WHY HIGH SPECIES DIVERSITY PATTERNS?? DO TO... NUMBER OF SPECIES ON SURTSEY, A NEW ISLAND • • • • COMPLEXITY OF HABITAT DIVERSITY OF HABITAT RESULT IN MORE DIVERSE NICHE SPACE MORE NICHE SPACE--MORE SPECIES ARE ABLE TO OCCUPY NICHE SPACE • IF SPECIES “LEARN” TO PARTITION RESOURCES WHY?? (CONT’D) • TROPICS HAVE GREATER “EVENNESS” IN CLIMATE--FEWER EXTREMES (TEMP) • LONGER GROWING SEASON • LONGER HISTORY...LESS AFFECTED BY GLACIAL ACTIVITY • GREATER HABITAT DIVERSITY...LEADS TO GREATER NUMBER OF NICHES • HIGHER SPECIES DIVERSITY/MORE STABLE BEECH-MAPLE WOODLOT--CURTISS ROAD, YPSILANTI, MI ca. FALL, 1964 CLIMAX COMMUNITY STABILITY • HIGHER SPECIES DIVERSITY • EVOLVED TO CONDITIONS WITH LESS DIRECT COMPETITION • GREATER RESOURCE PARTITIONING • MORE SPECIES...HIGHER STABILITY OF COMMUNITY STRUCTURE VIRGIN BEECH-MAPLE FOREST, PAOLIA, IN (FALL 1970) 9 VIRGIN BEECH-MAPLE FOREST, PAOLIA, IN (FALL 1970) NICHE CONCEPT: FUNCTIONALITY • GIVEN: EACH SPECIES HAS ITS OWN TIME & PLACE IN COMMUNITY, DIFFERENT FROM OTHER SPECIES--INTEREST IN CONCEPT • HABITAT • NICHE SPECIES INTERACTIONS & CONCEPT OF NICHE • HABITAT = WHERE ORGANISM LIVES • NICHE = ROLE/JOB OF ORGANISM IN COMMUNITY (FUNCTION) – PRODUCER, CONSUMER, DECOMPOSER • NICHE = SPATIAL POSITION IN HABITAT – DEFINED BY MULTIPLE ENVIRONMENTAL FACTORS HABITAT • KIND OF ENVIRONMENT IN WHICH SPECIES IS FOUND – DESCRIBE IN TERMS OF PHYS/CHEM ASPECTS OF SETTING – TOPOGRAPHY – SPECIES COMPOSITION • SINGLE SPECIES MAY OCCUPY A RANGE OF DIFFERENT HABITATS HABITAT NICHE • DIFFERENT SPECIES MAY OCCUPY SIMILAR HABITATS • APPLIED TO DEFINE THE DEGREE OR MANNER OF SPECIALIZATION OF SPECIES IN A PARTICULAR HABITAT – BOTTOM DWELLERS (CRABS, LOBSTERS, ETC) • ECOLOGICAL EQUIALENTS OR ECOLOGICAL COUNTERPARTS • DIFFERENT SPECIES FILLING SIMILAR HABITATS GEOGRAPHICALLY – FUNCTIONAL RELATIONSHIPS TO OTHER SPECIES –SPACE –TIME 10 NICHE • DEFINED AS THE SPECIES POSITION IN THE COMMUNITY • A NUMBER OF NICHES IN AN AREA MEANS A HIGHER DEGREE OF SPECIALIZATION OF SPECIES REPRESENTED • DEFINES AN EVOLUTIONARY/GENETIC FUNCTION WITHIN SPECIES COMPLEX NICHE: SPATIAL CONCEPT – TIME, ENVIRONMENTAL CONDITIONS ARE STIMULI SPATIAL CONCEPT OF NICHE SPECIES INTERACTIONS • SPACING PATTERNS • G.E. HUTCHINSON (1957), A YALE SCHOLAR: “THE NICHE IS AN ABSTRACTLY INHABITED HYPERVOLUME” • CONCEPT OF DIMENSIONALITY OF CONTROL FACTORS • FUNDAMENTAL VS. REALIZED NICHE – RANDOM – CLUMPED (AGGREGATION) – EVENLY SPACED--REGULAR-(HYPERDISPERSION) • EVALUATE TYPE OF DISPERSION (DISTRIBUTION) BY POISSON STATISTICS SPECIES DISTRIBUTION PATTERNS 11 TYPES OF COMPETITION • INTRASPECIFIC COMPETITION – INTERACTIONS BETWEEN INDIVIDUALS OF SAME SPECIES • INTERSPECIFIC COMPETITION – INTERACTIONS BETWEEN INDIVIDUALS OF DIFFERENT SPECIES • HUMIDITY NICHE SPACE/OVERLAP NICHE SPACE/OVERLAP • HUMIDITY SYMPATRIC DISTRIBUTION SPECIES A SPECIES A ALLOPATRTIC DISTRIBUTION SPECIES B TEMPERATURE COMPETITIVE INTERACTION • NO OVERLAP OF NICHE SPACE – ALLOPATRIC DISTRIBUTION – NO COMPETITION • OVERLAP OF NICHE SPACE SPECIES B TEMPERATURE – SYMPATRIC DISTRIBUTION – DEGREE OF COMPETITION DEPENDS UPON AMOUNT OF OVERLAP – SPACE, TIME, SEASON, RESOURCE USE 12 RESOURCE PARTITIONING • PROCESS IN NATURE WHERE TWO OR MORE SPECIES OCCUPY SAME NICHE SPACE FIGURES ILLUSTRATE EXTREMES IN RESOURCE PARTITIONING SCHEME % OF DIET – SOME OF THE TIME – COMPETE FOR SAME OR SIMILAR RESOURCES – SHARE RESOURCE & ALLOW FOR MUTUAL EXISTENCE IN SAME NICHE SPACE FEEDING NICHE OF BLUE-GRAY GNATCATCHER CAPTURE OF INSECT PREY OF DIFFERENT SIZES TAKEN AT DIFFERENT HEIGHTS ABOVE THE GROUND TERNS ON CHRISTMAS ISLAND FISH BODY LENGT, CM NICHE CONEPT: ISSUES OF SPECIES CO-EXISTENCE • CO-EXIST IF POPULATIONS SUBJECT TO DIFFERENT CONTROLS (RESOURCE LIMITS OR OTHER POPUL. REG. MECHANISMS) • CO-EXIST IF OCCUPY DIFFERENT SPACES-DIFFERENT HABITATS WITHIN SAME GENERAL AREA • CO-EXIST WITHIN SAME COMMUNITY IF THEY RELATE DIFFERENTLY TO RESOURCES AND/OR OTHER SPECIES IN COMMUNITY SPECIES CO-EXIST IN STABLE COMMUNITY, IF: • DIFFER IN HORIZONTAL & VERTICAL POSITION • TIME RELATIONS • RESOURCE UTILIZATION • KIND OF INTERACTION WITH OTHER SPECIES OR IN THE MANNER OF POPULATION CONTROL 13 FUNDAMENTAL NICHE: ALL POSSIBLE PLACES/POSITIONS OF SPECIES WITHIN HABITAT • ENVIRONMENTAL CONTROL FACTORS PROJECTED INTO n-DIMENSIONAL SPACE • DEGREE OF HYPERVOLUME (SPATIAL) OVERLAP A FUNCTION OF COMMONALITY OF VARIABLES REALIZED NICHE FUNDAMENTAL NICHE • COMMUNITY NICHE RELATIONSHIPS REFLECT n-DIMENSIONAL COMPONENTS • EACH SPECIES HAS ITS OWN POSITION (OR NICHE) WITH A CENTRAL LOCATION THAT DIFFERS FROM OTHER SPECIES, BECAUSE OF: –EVOLUTIONARY PROCESSES (INCLUDING REDUCED COMPETITION) –LEADS TOWARD SCATTERING OR DISPERSION OF SPECIES IN NICHE SPACE FIVE (5) WARBLER SPECIES OCCUPYING DIFFERENT NICHE SPACE IN CONIFER • COMPETITIVE INTERACTION RESULTS IN EITHER EXTINCTION OR CO-EXISTENCE • COMPETITION PARTITIONS NICHE SPACE, RESTRICTING SPECIES TO PART OF FUNDAMENTAL NICHE • THUS, REALIZED NICHE ACTUALLY SMALLER IN SPATIAL EXTENT (VOLUME) THAN FUNDAMENTAL NICHE COMPETITIVE EXCLUSION PRINCIPLE (GAUSE) COMPETITIVE EXCLUSION PRINCIPLE (GAUSE) • IF TWO SPECIES OCCUPY THE SAME NICHE IN THE SAME STABLE COMMUNITY, ONE WILL BECOME EXTINCT • NO TWO SPECIES OBSERVED IN STABLE COMMUNITY ARE DIRECT COMPETITORS LIMITED BY SAME RESOURCES – THEY DIFFER IN NICHE REQUIREMENTS IN WAYS THAT REDUCE COMPETITION BETWEEN THEM • NO TWO SPECIES MAY OCCUPY THE SAME NICHE SPACE – AT SAME TIME – ALL OF TIME – UTILIZING SAME RESOURCES – AND SURVIVE • OUTCOME: ONE OR BOTH BECOME EXTINCT 14 COMPETITIVE EXCLUSION (CONT’D) • TWO SPECIES CANNOT COEXIST INDEFINITELY IN SAME HABITAT IF THEY REQUIRE IDENTICAL RESOURCES (NICHE SPACE) • ONE OR BOTH MAY BECOME EXTINCT SPECIES CO-EXISTENCE • NICHE SPACE OVERLAP • RESOURCE PARTITIONING • RESULTS IN MORE SPECIES IN SAME HABITAT • INCREASED SPECIES DIVERSITY • INCREASED COMMUNITY STABILITY – “COMMUNITY” SURVIVES IN FACE OF ADVERSE ENVIRONMENTAL CHANGE...TO A POINT BIOMES • MAJOR INTEGRATION OF ECOSYSTEMS ON A LARGE SCALE – OVER LARGE EXPANSE OF LANDSCAPE • BIOMES CHARACTERIZED IN TERMS OF: – VEGETATION – CLIMATE – SOIL TYPE – ANIMALS ALPINE TUNDRA SEVEN MAJOR BIOMES: • • • • • • TUNDRA TIAGA (BOREAL/CONIFEROUS) FOREST DESERT (HOT & COLD) PRAIRIE DECIDUOUS FOREST TROPICAL RAIN FOREST ALPINE LANDSCAPE--ABOVE TREELINE 15 ALPINE VEGETATION @ TREELINE ALPINE VEGETATION @ TREELINE ALPINE BOREAL FOREST--CLINGMANS DOME PINE FOREST IN NORTHERN MICHIGAN GRASSLAND--PRAIRIE VEGETATION TALLGRASS PRAIRIE VEGETATION 16 DESERT VEGETATION, SOUTHERN ARIZONA DESERT VEGETATION, SOUTHERN ARIZONA SAND PLAINS VEGETATION: LONG LEAF PINE (IN DEPRESSION) & TURKEY OAK (ON RIM OF DEPRESSION) IN COASTAL PLAIN, NC DESERT FLOWERS, SOUTHERN ARIZONA TURKEY OAK BOG MAT VEGETATION: NORTHERN MICHIGAN BOG ORCHID: CALOPOGON 17 CATHEDRAL WOODLOT @ CMU--1977 LOOKING SOUTH-SOUTHEAST EAST CATHEDRAL WOODLOT @ CMU--1977 LOOKING EAST VEIT’S OLD FIELD: SPECIES DIVERSITY MAP BASED ON STUDY BY BAILEY & CHANEY TOPOGRAPHIC MAP OF VEIT’S OLD FIELD SHOWING SAMPLE PLOTS 18