Community Ecology Outline
Community Ecology Outline FOR 332
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This 10 page Bundle was uploaded by Solimar Garcia on Friday October 30, 2015. The Bundle belongs to FOR 332 at University of Wisconsin - Stevens Point taught by James Cook in Summer 2015. Since its upload, it has received 113 views. For similar materials see Forest Ecosystem Ecology in Agriculture and Forestry at University of Wisconsin - Stevens Point.
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Date Created: 10/30/15
FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS 1 WHAT IS A COMMUNITY a Community concept how do we use it i To in uence the number of genotypessometimes mortality for certain genotypes number of parents involve in reproduction increase genetic variation ii You can identify for management purposes classify communities that we have exist iii Generalize a community type aggregation of plants typical conditions for the type of community iv Used for ecological hierarchy too b It s the aggregation of plants and animals living together and occupying a common area 11 Handout example figure 1 what determines composition 0 an area at a point in time Ecotone may only be one foot wide depending on the area on side of mountain ecotone may be 1000s of feet broad and gradual a Staticfixed external i Bedrock in uences soil properties that develop ii Hydrology not as fixed iii Indirect indicators altitude latitude climate temperature moisture timing of events iv Climate b Biotic material i Potential species pool all the species that could show up is not only what s surrounding but also from seed bank dormant seeds in litter layer soil which can persist many years I thousand to 4 thousand seeds per meter squared light temperature and moisture maybe seeds that are no longer in the community 1 Example beech in WI only on eastern coase along all of lake Michigan Glacial in uence they came from the south approx 4000 years ago came inform either the UP or souther lake Michigan looking at pollen grain in FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS old logs to show route when it got anywhere hemlock traveled west from Michigan s UP and eastern WI c Abiotic material site conditions soil and climate sets ultimate limit d Dynamic external natural disturbances i Weather daily ii Fire water landslides mudslides fire dependent communities wind throw storms provides area for new plants e Internal factors species that reside w I community 111 IMPORTANT CHARACTERISTICS of TERRESTRIAL COMM s a Biota primarily above ground see handout b Attributes i Composition related to which species is resent its richness and diversity and relative abundance c Structure i Vertical structure spiders birds feeding habitat 1 Layers strata snags canopy gaps from wind throw ii Forest oor structure 1 Coarse wood debris CWD and pits and mounds decomposers arthropods bacteria and fungi 2 Small animal habitat seedbed for yellow birch and hemlock insect because more moisture 3 For amphibians subnivian below ground travel corridors iii Size and range in diameter of tree iv Pattern 1 Phenology part of the year present timing of growth for owering seed dispersal v Successional stage pioneer vs seral vs late stage FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS IV DIVERSITY DEFINITIONS SPATIAL SCALE amp DETERMINANTS a Diversity vs biodiversity i Biodiversity includes genetic and all appropriate ecological scales ii Diversity is the richness and evenness number of spp and relative abundance 1 When measuring only do so within a taxonomic group for example herps fungi birds b Point Species density quadrat size c Alpha community level d Beta Comparing how different 2 or more species communities are in comparison to each other e Gamma distinct landscape level f Diversity in Forests some general patterns i Diversity is strongly linked to quotagequot years since a major disturbance amp long term implications ii Diversity patterns often vary among taxonomic groups Sets in motion changes that will be noticeable for 100 years iii Often increases as size of community increases 1 Even if same age or same management practices though no increase indefinitely iv Decreases with isolation v Heterogeneity differences is key for all taxonomic groups 1 Variation in quothabitatsquot for group of interest is most important g side note there is no single consistent pattern of richness after significant disturbance always a variety You need info that is specific to your particular region of interest h Final Remarks on Diversity i Difficult and time consuming limited to technology ii Not consistent at a community scale maybe at landscape level but changes are relatively short period of time at comm Level iii Sampling related challenges FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS 1 Go out multiple times to get full sample at different times of the year 2 Will not ever sample all species iv Tension Zone in WI band along the state where northern species don t cross below and quotsouthernquot species don t cross above Ecotone scale to Biome scale the potential species pool is greater in the TZone because of the overlap V DISTURBANCE REGIMES Disturbance is natural destruction plus change in environmental conditions or vital resources that elicits response there is also destruction of above ground biomass and discrete event that disrupts composition a Components of a regime i Intensity measuring potential impact 0 the event itself 1 Low high intensity ie fire how much heat generated as it moves up hillside 2 The phenomenon itself impact caused is the severity which is di eren t ii Frequency number of events per unit of time or number of years between events iii Areal extent number of acres scale of acres iv Time of year relative to phenology 1 fire a different time of year can vary in severity v Duration 1 Can be important to fire and important for oods because water can sit for much longer in ood plain after the actual ood vi Variation 1 Overtime among locations within a type 2 Highly relevant to adaptations and susceptibility 1 Is it regular or irregular 2 ie serotinus cones may only be helpful occasionally if more regular or consistent them fore adaptedhelpful Plants adopt FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS phenology no advantage if drop seeds in April if oodplain in October changes vii Severity Gauging over story and forest oor 1 Tornado for over story severe attened oor Minimal 2 Fire cut amp burn litter layer gone severe for both oor and over story b Impacts on forests amp community response see handout too i Heterogeneity coarse woody debris CWD and microclimate wind patch level and community wide ii note on variation severity and extent of heterogeneity happens among a community example of Yellowstone fire Different impacts a single disturbance different levels of response c Roles of Disturbance i Landscape level heterogeneity in uences different communities to a different degree ii Structure of a forest community iii Composition direct succession iv Selective forces must be relatively consistent and frequent not all disturbances are selective forces v Interactions among types of disturbance wind throw CWD fuel for fire vi Nutrient cycling will be covered in ecosystem unit VI SUCCESSION a Historical Review i Illustration 1 compositional changes over time ie example of N Rocky Mtns after fire structural changes ii Early thinking of Clements and Gleason 1 Clements Organismic theory which has some correct components a Unidirectional biologically driven predictable stable climax stage FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS b Key mechanisms are facilitation and competition Pioneer to Seral to Climax 2 Gleason counterpart to Clements model still used a Not as predictable in succession not same over same soil composition b No climax c Key mechanisms are weather and seed products and dispersal mechanisms and autecology b Stages amp pathways i Illustration 2 Up to 3 or 4 different pathways in the same climatic conditions Not as Clements illustrated ii Different sequences of stages occur pioneer plants are firs to emerge after disturbance iii Multiple pathways are the norm iv Clements theory tossed aside about 1970s V Succession can move in other directions away from stable climax conditions vi Illustration3 alternatives 1 Pioneer stages vary dominated by shrubs or herbs variability in composition from site to site Gleason c Contributing Factors Mechanisms weather unpredictable i Autecology seedbank and local seed pool ii Chance interactions with herbivory and competition iii Physiography iv Depth to water table soil composition d Handout Fig 1 Jack Pine i What is likely to include in all possibilities based on field work ii After clearcutting led to perm sedge iii After burning 3 diff possibilities 1 Carex meadow jackpine and hardwood and shrubs 2 Seed bank to hardwood w shrubs 3 Duration of burn for IP and HW intensity for IP FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS a If serotinus cones opened with enough heat or seared from to much heat 4 Sprouting via asexual means which means they were present in previous stages 5 Current conditions are a factor of what was there and where we re headed 6 Arrested succession stays in the stage longer than the norm a Pioneer stage short lived prevents other stages from occurring e Handout N Rockies 1 ii iii iv vi Know all variables and labels msexual maturity elocal extinction extirpation llongevity Iintolerant Ttolerant cseeds stored in canopy serotinus Dwind dispersed seeds bregeneration availability Why is le at infinity for Hemlock Because it will persist regarless of what happens shade tol Solid arrow are changes that occur in absence of disturbed conditions and dotted lines are disturbances which push succession along Fire can bring Pine again which can reoccur for 1000s of years in a cycle As Pine canopy in place hemlock emerges no fire some larch seeds in before the canopy closes Pine dies naturally hemlock builds up because of shade to readily moves op and larch may emerge still with gap as pine senesce f Modern View i ii iii iv Multiple pathways Multiple directions Disturbance regimes integral part Autecology of dominant keyspp can be low in abundance but still important we need the natural history of the forest spp FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS V Chance events shape process a degree of uncertainty 1 No 100 assurance if we know the current composition of the seed bank and autecology can be 7078 Weather can undercut us w random change vi Stability stage is RARE 1 Bigger differences over longer time frames a seral stage will change w or wo disturbance vii Mechanisms driven factor contributing to successional change several mechanisms at the same time viii Local common components we know about succession current level or understanding Land use history ix Uncommon components 1 Arrested amp accelerated succession VII Plant Invasion a Ecological foundation i Invasive that move in can cause problems and interfere with our management plan ii Woody exotics in the US are a concern because they have many ecological effects almost 14 plants are nonnative b Foundation i European and aisian are the most problematic exotics ii Process by which exotics impact the ecology doesn t happen overnight 1 Disperse or transport humans are primary means intentional or not 2 Establish conditions must be suitable for germination and maturing for sexual reproduction c Principals i Why not everywhere Chance mostly 1 Site conditions can be coarse filter 2 Species pool 3 Human in uence 4 Propatule pressure FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS 5 Disturbances not in every case but many cases severity intensity and time of year amp freq d Why does invasion occur Classic viewpoint i Primary succession 1 If unfilled niche more likely be invaded ii Richness of community BUT evidence is WEAK 1 The spp occupying a site are not necessarily those best adapted to compete 2 If space available and to to site then may survive 3 No other competitive forces iii When a community is disturbed this provides opportunity for invasive because decrease in competition iv More microenvironments 1 pH CWD shade cover v Landscape structure in uences how many exotic invasive are in local pool e Success of Invasives i Human role fragmentation introduction human disturbance human altered disturbance regimes ii Frequency of disturbed places iii Site conditions iv High propagule pressure v Highly heterogeneous conditions 1 Having 2 or more of these conditions greatly increases likelihood of invasion f Concern for Ecological Effects i Structure ii Composition richness exculsion of natives iii Intersections 1 Indirectallelopathy iv Frequency intensity of fire 1 Western grassland exotic increased fire freq 2 Buckthorn increase moisture reducing fire v Direct succession FOR 332 COMMUNITY ECOLOGY OUTLINE 8 KEY CONCEPTS 1 Depends on management objectives if an invasive blocks a particular keystone spp prevents not only that spp but also its associates vi Change ecosystem processes 1 Nutrient cycling and rate of decomposition amount of nutrients present amount of leaf litter can change because of invasives vii Aliens Selective force exotics can be selective fore for more spp not inherently bad viii Facilitate further invasion 1 First make it easier for 2nd to invade g Successful invasion due to these traits i Short regeneration time ii Large number of seeds iii Long distance dispersal mechanisms iv High phenotypic plasticity v Generalist pollination system windwater vi High capacity for asexual spread
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