- Количество слайдов: 51
To Be or Not to be a Quercus Bur Oak Quercus macrocarpa St Paul California Blue Oak Justin Quercus Borevitz Prairie Ecosystems 4/19/07
• Wood/lignin evolved 3 times in angiosperms – Asters, grasses (bamboo), legumes • Oaks Hard wood, slow growing • Old growth, 400 years! 2 stories high. . • Obligate hosts (fungal, insect/ant farming) – Edwards hairstreaks • Sudden Oak Death • Syndrome (SODS) – California?
Looks like a hybrid… Limited hybridization between Quercus lobata and Quercus douglasii (Fagaceae) in a mixed stand in central coastal California Kathleen J. Craft 2, Mary V. Ashley 2, 4 and Walter D. Koenig 3 American Journal of Botany. 2002; 89: 1792 -1798. ) We conclude that adult hybrids of Q. douglasii x Q. lobata are rare at this site and plasticity in morphological characters may lead to overestimates of hybridization among Quercus species (Cali - valley oak, blue oak) Mary V. Ashley Professor UIC Biological Sciences . . found that over half of the acorns from isolated stands are pollinated by trees outside the stand, at great distances. Within the stand, pollinations occurred nearly at random. We have clearly demonstrated that the mating system of the bur oak. . Model for Speciation, catch it in the act. . Hmm easy to catch since they done go anywhere fast
Quercus rubra, Red Oak, Quercus muhlenbergii, Chinkapin oak, chinquapin oak, yellow chestnut oak
Tree of Life • Dycotiledonae: Hamamelididae: Fagales: Fagaceae • Taxonomy browser • Genome Project! English oak 1439 ESTs • http: //www. genome. clemson. edu/projects/fagaceae/ • Quercus robur is one of between 300 and 600 species of oak distributed over the entire northern hemisphere. The physical size of the genome is larger than many other woody angiosperms while being among the lower values of plants. Study of Quercus robur is one of the entry points for study of the Fagaceae and allows comparative genomics to become a field of study in woody angiosperms.
• Research Paper Plant biol (Stuttg) 2007; 9: 116 -126 DOI: 10. 1055/s-2006 -924542 Genetic Variation and Differentiation Within a Natural Community of Five Oak Species (Quercus spp. ) A. L. Curtu 1, O. Gailing 1, L. Leinemann 1, R. Finkeldey 1 • Oaks (genus Quercus - Fagaceae) are amongst the most common tree species in the temperate and Mediterranean parts of the Northern hemisphere ([Nixon, 1993]). Because of their high ecological and economical importance, but also due to their propensity to hybridize (e. g. , [Burger, 1975]), oaks have been the focus of intensive research and have become long-standing models in evolutionary genetics. • Only the very rare chloroplast variants are species-specific, and consequently there is a nearly complete lack of differentiation between the two species, Q. robur and Q. petraea
Chesnuts in their bur Bur Oak
• evergreen (Q. ilex, Q. coccifera, Q. suber), • semi-deciduous (Q. trojana, Q. frainetto), • deciduous habits (Q. cerris, Q. pubescens, Q. robur, Q. petraea) • all in Italy!
WHAT ARE GOVERNMENTAL BODIES DOING? • City of Los Angeles protects larger Oaks on large properties • County of Los Angeles protects large Oak trees • Pasadena protects larger “native trees” • City of Bakersfield has no tree protection ordinances • State of California has pending Oak tree conservation legislation • City of Visalia protects Valley Oaks
OAK TREE REMOVAL MITIGATION • Attempt to replace the “value” of what is lost • Minimum by law 2: 1 15 gallon replacement • Minimum in practice, 2: 1 36” box size replacement • No limit on the amount of replacement mitigation
Nutrition • • • Heterotrophic Secrete extracellular enzymes Absorptive nutrition Saprobes: decay dead organic matter pathogens: biotroph, necrotroph symbionts: parasites - commensals - mutualists
A Cooperative Research: USDA Forest The Israel Service International Forest Authority Programs (KKL) Curtis Flather, Ronen Kadmon, Rocky Mountain Research Center, USDA Forest Service Department of Ecology, The Hebrew University of Jerusalem Denis Dean, Department of Forest Sciences, Colorado State University
Adult oaks (Quercus calliprinos) in Mt. Meron
Herbaceous vegetation in the front, recovering trees in the back, Mt
Earlier stages of recovery following land abandonment dwarf shrubs, tall shrubs, and low trees in Mt. Meron
30 years after abandonment of pastoral cultivation in Mt. Meron
Mt. Meron 1945
Mt. Meron 1964
Mt. Meron 1992
Mediterranean type ecosystems
Average annual change Mediterranean vegetation change in long-term, landscape-scale studies
Why is there such a difference between vegetation dynamics in California and the Mediterranean basin? 1. Local ecological and anthropogenic conditions 2. Different soils 3. Different evolutionary history
A transplant experiment is currently conducted, where oaks from both countries are grown together in both sites, in a controlled environment
Phylogenetic structure of long-term experimental communities at Cedar Creek Natural History Area, Minnesota Charles G. Willis University of Minnesota – Twin Cities
What is phylogenetic structure? Phylogenetic structure describes the phylogenetic relationships of species neighbors within a given community. In other words, are neighbors closely related or distantly related evolutionarily?
Phylogenies A Phylogeny represents the evolutionary relatedness and history of a given set of species
Patterns of Phylogenetic Structure communities Phylogenetic clustering Phylogenetic overdispersion
Why look at phylogenetic structure? Phylogenetic structure can provide insight into what ecological mechanisms determine community assembly. In other words, by looking at the evolutionary relationships of neighboring species, we can come to conclusions on what ecological mechanisms allowed the species to be neighbors in the first place.
Community Assembly Modern ecologists tend to define communities between the contrasting views of Clements and Gleason, with a stronger inclination toward Gleason. Although there is interdependence in communities, by and large communities tend to be better represented as groups of independent individuals falling out along their niche dimensions Gleason Community Abundance Clements Community Environmental gradient
Community Assembly Rules Several ecological processes have been put for to explain how and why communities assemble. Environmental filtering is the process whereby species are precluded from a habitat due to biophysical limited of the species morphology. • Competitive exclusion is the process whereby species are precluded from a habitat due to competition with a superior competitor. • Neutral theory is the process whereby species occurrence in a community is driven by species abundance and stochastic colonization during dispersal
Community Assembly Rules Environmental Filtering Competitive Exclusion Species A BC Traits Species ABC DE F GH I D E F GH I Communities Traits Communities
Phylogenetic Structure and Community Assembly Rules Phylogenetic structure can be used to determine the ecological mechanisms of community assembly with additional information on the evolutionary history of species traits
Integration and Explanation: Phylogenetic Overdispersion
Integration and Explanation: Phylogenetic Clustering
Determining Phylogenetic Structure: A Matter of Scale is the level at which a system is observed. There are several scales with numerous levels to be studied in ecology and evolution. Three of the most important ones for this study include: Spatial Scale – the physical boundary by which a community is considered Temporal Scale – the unit of time over which a community is considered Cladistic Scale – the number of branches on a phylogeny that are considered.
Methods Phylogenetic Distances Pairwise Co-occurance Cih =1 - 0. 5*S|pij - phj| This method of analysis was run using programs designed by Jeannine Cavender. Bares and Clarence Lehman Correlation Co-efficient
Methods: Null Models allow for statistical analyses of data sets that are not normal distributed as in the case of phylogenetic distances between species pairs and for statistical analyses of relationships that might have a weak correlation. We used null models in our analyses to compare the correlation co-efficient between phylogenetic distance and co-occurrence for observed data to the correlation co-efficient of a 1000 randomly generated data sets These random data sets where generated from existing the existing data sets, and basically consisted of randomly shifting species abundances around within plots.
Communities at Cedar Creek Three large data sets available from Cedar Creek provide an excellent opportunity to apply these analyses to Minnesota prairie-savanna communities Oak-Savanna Burn Nitrogen Addition Old-Field Succession Experiment – E 133 Experiment – E 001 Experiment – E 014
Oak-Savanna Experiment: Analysis and Results Experimental Background This study examines the effects of long-term prescribed burning treatments on vegetation structure and composition, productivity, and nutrient cycling in oak savanna communities. Burning as been occurring on certain plots since 1964. Plots are prescribed a burn frequency of years along a gradient of “no-burn” to every 2 -3 years. Vegetation surveys of the savanna burn units began in 1984 and have been carried out roughly every five years since then. Previous results: Fire suppresses shrubs and trees and favors native prairie species. Responses of plant species to burning, however, are related to season of burning intensity and frequency of fires. Plant species respond in an individualistic manner.
A tree of Cedar Creek Poaceae Asteraceae Eurosid 1
Explanation: Evolutionary Cedar Creek is an open community. All species that exist here have evolved ex situ, colonized the region only after glacial retreat 12, 000 years ago.
Explanation: Evolutionary Post-glacial colonization is individualistic (Davis and Shaw 2001). Species advance upward following the retreating glacier line along their niche dimensions. Compositional patterns that existed 10, 000, 6, 000 or even 1, 000 years ago are not seen today At large, scales these niches tend to be conserved through strong stabilizing selection i. e. environmental filtering. If traits necessary for colonization are conserved among lineages than it is likely that communities will be phylogenetically clustered.
Explanation: Ecological Oak-Savannas • Similar explanations could explain the patterns observed in the oak-savanna analyses. At finer spatial scale, stochastic ecological processes might ‘muddle’ detectable patterns phylogenetic structure, but at a larger scale, strong patterns in phylogenetic structure are detectable. • As with the N addition fields, the Oak-savanna plots are often both environmentally and compositionally heterogeneous thus encouraging ‘random’ events of colonization and population fluctuations.
Conclusions At larger scales patterns in phylogenetic structure are clustered. This suggests that traits necessary to inhabit these communities are conserved. This prediction fits in with the individualist idea of post-glacial invasion in the area and the effects of environmental filtering acting with niche conservatism in the assembly of open communities.