TY - JOUR T1 - Genotypic variation in foundation species generates network structure that may drive community dynamics and evolution. JF - Ecology Y1 - 2016 A1 - Lau,Matthew K A1 - Keith,Arthur R A1 - Borrett,Stuart R A1 - Shuster,Stephen M A1 - Whitham,Thomas G KW - Animals KW - Biological Evolution KW - Computer Simulation KW - Food Chain KW - Genetic Variation KW - Genotype KW - Insecta KW - Models, Biological KW - Populus AB -

Although genetics in a single species is known to impact whole communities, little is known about how genetic variation influences species interaction networks in complex ecosystems. Here, we examine the interactions in a community of arthropod species on replicated genotypes (clones) of a foundation tree species, Populus angustifolia James (narrowleaf cottonwood), in a long-term, common garden experiment using a bipartite "genotype-species" network perspective. We combine this empirical work with a simulation experiment designed to further investigate how variation among individual tree genotypes can impact network structure. Three findings emerged: (1) the empirical "genotype-species network" exhibited significant network structure with modularity being greater than the highly conservative null model; (2) as would be expected given a modular network structure, the empirical network displayed significant positive arthropod co-occurrence patterns; and (3) furthermore, the simulations of "genotype-species" networks displayed variation in network structure, with modularity in particular clearly increasing, as genotypic variation increased. These results support the conclusion that genetic variation in a single species contributes to the structure of ecological interaction networks, which could influence eco-ogical dynamics (e.g., assembly and stability) and evolution in a community context.

VL - 97 SN - 0012-9658 UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=27197399&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 3 ER - TY - JOUR T1 - Community specificity: life and afterlife effects of genes. JF - Trends in plant science Y1 - 2012 A1 - Whitham,Thomas G A1 - Gehring,Catherine A A1 - Lamit,Louis J A1 - Wojtowicz,Todd A1 - Evans,Luke M A1 - Keith,Arthur R A1 - Smith,David Solance KW - Animals KW - Arthropods KW - Biological Evolution KW - Ecosystem KW - Genotype KW - Herbivory KW - Host-Parasite Interactions KW - Models, Biological KW - Plants KW - Species Specificity AB -

Community-level genetic specificity results when individual genotypes or populations of the same species support different communities. Our review of the literature shows that genetic specificity exhibits both life and afterlife effects; it is a widespread phenomenon occurring in diverse taxonomic groups, aquatic to terrestrial ecosystems, and species-poor to species-rich systems. Such specificity affects species interactions, evolution, ecosystem processes and leads to community feedbacks on the performance of the individuals expressing the traits. Thus, genetic specificity by communities appears to be fundamentally important, suggesting that specificity is a major driver of the biodiversity and stability of the world's ecosystems.

VL - 17 SN - 1360-1385 UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=22322002&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 5 ER - TY - JOUR T1 - Genetic components to belowground carbon fluxes in a riparian forest ecosystem: a common garden approach. JF - The New phytologist Y1 - 2012 A1 - Lojewski,Nathan R A1 - Fischer,Dylan G A1 - JK Bailey A1 - Jennifer A Schweitzer A1 - Whitham,Thomas G A1 - Stephen C Hart KW - Carbon KW - Carbon Cycle KW - Carbon Dioxide KW - Chimera KW - Crosses, Genetic KW - Ecosystem KW - Genetic Variation KW - Genotype KW - Populus KW - Soil KW - Trees AB -

Soil carbon dioxide (CO(2)) efflux is a major component of terrestrial carbon (C) cycles; yet, the demonstration of covariation between overstory tree genetic-based traits and soil C flux remains a major frontier in understanding biological controls over soil C. Here, we used a common garden with two native tree species, Populus fremontii and P. angustifolia, and their naturally occurring hybrids to test the predictability of belowground C fluxes on the basis of taxonomic identity and genetic marker composition of replicated clones of individual genotypes. Three patterns emerged: soil CO(2) efflux and ratios of belowground flux to aboveground productivity differ by as much as 50-150% as a result of differences in clone identity and cross type; on the basis of Mantel tests of molecular marker matrices, we found that c. 30% of this variation was genetically based, in which genetically similar trees support more similar soil CO(2) efflux under their canopies than do genetically dissimilar trees; and the patterns detected in an experimental garden match observations in the wild, and seem to be unrelated to measured abiotic factors. Our findings suggest that the genetic makeup of the plants growing on soil has a significant influence on the release of C from soils to the atmosphere.

VL - 195 SN - 0028-646X UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=22642377&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 3 ER - TY - JOUR T1 - The relative influences of host plant genotype and yearly abiotic variability in determining herbivore abundance. JF - Oecologia Y1 - 2012 A1 - Evans,Luke M A1 - James S Clark A1 - Whipple,Amy V A1 - Whitham,Thomas G KW - Animals KW - Bayes Theorem KW - Genotype KW - Herbivory KW - Mites KW - Population Density KW - Population Dynamics KW - Populus AB -

Both plant genotype and yearly abiotic variation affect herbivore population sizes, but long-term data have rarely been used to contrast the relative contributions of each. Using a hierarchical Bayesian model, we directly compare effects of these two factors on the population size of a common herbivore, Aceria parapopuli, on Populus angustifolia × fremontii F(1) hybrid trees growing in a common garden across 8 years. Several patterns emerged. First, the Bayesian posterior estimates of tree genotype effects on mite gall number ranged from 0.0043 to 229 on a linear scale. Second, year effect sizes across 8 years of study ranged from 0.133 to 1.895. Third, in comparing the magnitudes of genotypic versus yearly variation, we found that genotypic variation was over 130 times greater than variation among years. Fourth, precipitation in the previous year negatively affected gall abundances, but was minimal compared to tree genotype effects. These findings demonstrate the relative importance of tree genotypic variation in determining herbivore population size. However, given the demonstrated sensitivity of cottonwoods to drought, the loss of individual tree genotypes from an altered climate would have catastrophic impacts on mites that are dependent upon these genotypes for their survival.

VL - 168 SN - 0029-8549 UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=21918874&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 2 ER - TY - JOUR T1 - Phenotypic variation in nurse traits and community feedbacks define an alpine community. JF - Ecology letters Y1 - 2011 A1 - Michalet,Richard A1 - Xiao,Sa A1 - Touzard,Blaise A1 - David S Smith A1 - Cavieres,Lohengrin A A1 - Callaway,Ragan M A1 - Whitham,Thomas G KW - arizona KW - Ecosystem KW - Genotype KW - Geum KW - Models, Biological KW - Phenotype KW - Plant Leaves KW - Plant Roots KW - Plant Stems KW - Population Dynamics KW - Selection, Genetic AB -

Much is known about facilitation, but virtually nothing about the underlying genetic and evolutionary consequences of this important interaction. We assessed the potential of phenotypic differences in facilitative effects of a foundation species to determine the composition of an Alpine community in Arizona. Two phenotypes of Geum rossii occur along a gradient of disturbance, with 'tight' competitive cushions in stable conditions and 'loose' facilitative cushions in disturbed conditions. A common-garden study suggested that field-based traits may have a genetic basis. Field experiments showed that the reproductive fitness of G. rossii cushions decreased with increasing facilitation. Finally, using a dual-lattice model we showed that including the cost and benefit of facilitation may contribute to the co-occurrence of genotypes with contrasting facilitative effects. Our results indicate that changes in community composition due to phenotypic differences in facilitative effects of a foundation species may in turn affect selective pressures on the foundation species.

VL - 14 SN - 1461-023X UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=21366815&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 5 ER - TY - JOUR T1 - A genetic basis to community repeatability and stability. JF - Ecology Y1 - 2010 A1 - Keith,Arthur R A1 - JK Bailey A1 - Whitham,Thomas G KW - Animals KW - Arthropods KW - Biological Evolution KW - Ecosystem KW - Genotype KW - Populus AB -

Recent studies have shown that genetically based traits of plants can structure associated arthropod and microbial communities, but whether the effects are consistent and repeatable across years is unknown. If communities are both heritable (i.e., related individuals tend to support similar communities) and repeatable (i.e., the same patterns observed over multiple years), then plant genetics may also affect community properties previously thought to be emergent, such as "stability." Using replicated clones of narrowleaf cottonwood (Populus angustifolia) and examining an arthropod community of 103 species, we found that (1) individual tree genotypes supported significantly different arthropod communities, which exhibited broad-sense heritability; (2) these findings were highly repeatable over three consecutive years (repeatability = 0.91) indicating that community responses to individual tree genotypes are consistent from year to year; (3) differences among tree genotypes in community stability (i.e., changes in community composition over multiple years) exhibited broad-sense heritability (H(C)2 = 0.32). In combination, these findings suggest that an emergent property such as stability can be genetically based and thus subject to natural selection.

VL - 91 SN - 0012-9658 UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=21141200&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 11 ER - TY - JOUR T1 - Genetic basis of aboveground productivity in two native Populus species and their hybrids. JF - Tree physiology Y1 - 2009 A1 - Lojewski,Nathan R A1 - Fischer,Dylan G A1 - JK Bailey A1 - Jennifer A Schweitzer A1 - Whitham,Thomas G A1 - Stephen C Hart KW - Ecosystem KW - Genotype KW - Hybridization, Genetic KW - Populus KW - Species Specificity KW - Utah AB -

Demonstration of genetic control over riparian tree productivity has major implications for responses of riparian systems to shifting environmental conditions and effects of genetics on ecosystems in general. We used field studies and common gardens, applying both molecular and quantitative techniques, to compare plot-level tree aboveground net primary productivity (ANPP(tree)) and individual tree growth rate constants in relation to plant genetic identity in two naturally occurring Populus tree species and their hybrids. In field comparisons of four cross types (Populus fremontii S. Wats., Populus angustifolia James, F(1) hybrids and backcross hybrids) across 11 natural stands, productivity was greatest for P. fremontii trees, followed by hybrids and lowest in P. angustifolia. A similar pattern was observed in four common gardens across a 290 m elevation and 100 km environmental gradient. Despite a doubling in productivity across the common gardens, the relative differences among the cross types remained constant. Using clonal replicates in a common garden, we found ANPP(tree) to be a heritable plant trait (i.e., broad-sense heritability), such that plant genetic factors explained between 38% and 82% of the variation in ANPP(tree). Furthermore, analysis of the genetic composition among individual tree genotypes using restriction fragment length polymorphism molecular markers showed that genetically similar trees also exhibited similar ANPP(tree). These findings indicate strong genetic contributions to natural variation in ANPP with important ecological implications.

VL - 29 SN - 0829-318X UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=19578030&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 9 ER - TY - JOUR T1 - Plant-soil microorganism interactions: heritable relationship between plant genotype and associated soil microorganisms. JF - Ecology Y1 - 2008 A1 - Jennifer A Schweitzer A1 - JK Bailey A1 - Fischer,Dylan G A1 - LeRoy,Carri J A1 - Lonsdorf,Eric V A1 - Whitham,Thomas G A1 - Stephen C Hart KW - Biomass KW - Crosses, Genetic KW - Ecosystem KW - Fatty Acids KW - Genetic Variation KW - Genotype KW - Host-Pathogen Interactions KW - Phospholipids KW - Plants KW - Soil Microbiology KW - Species Specificity AB -

Although soil microbial communities are known to play crucial roles in the cycling of nutrients in forest ecosystems and can vary by plant species, how microorganisms respond to the subtle gradients of plant genetic variation is just beginning to be appreciated. Using a model Populus system in a common garden with replicated clones of known genotypes, we evaluated microbial biomass and community composition as quantitative traits. Two main patterns emerged. (1) Plant genotype influenced microbial biomass nitrogen in soils under replicated genotypes of Populus angustifolia, F1, and backcross hybrids, but not P. fremontii. Genotype explained up to 78% of the variation in microbial biomass as indicated by broad-sense heritability estimates (i.e., clonal repeatability). A second estimate of microbial biomass (total phospholipid fatty acid) was more conservative and showed significant genotype effects in P. angustifolia and backcross hybrids. (2) Plant genotype significantly influenced microbial community composition, explaining up to 70% of the variation in community composition within P. angustifolia genotypes alone. These findings suggest that variation in above- and belowground traits of individual plant genotypes can alter soil microbial dynamics, and suggests that further investigations of the evolutionary implications of genetic feedbacks are warranted.

VL - 89 SN - 0012-9658 UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=18459340&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 3 ER - TY - JOUR T1 - Importance of species interactions to community heritability: a genetic basis to trophic-level interactions. JF - Ecology letters Y1 - 2006 A1 - JK Bailey A1 - Wooley,Stuart C A1 - Lindroth,Richard L A1 - Whitham,Thomas G KW - Animals KW - Aphids KW - Birds KW - Food Chain KW - Genotype KW - Plant Leaves KW - Populus AB -

Recent community genetics studies have shown that specific genotypes of a host plant support distinct arthropod communities. Building upon these findings, we examined the hypothesis that a trophic community consisting of cottonwood trees, a galling herbivore and avian predators could also be related to the genetics of the host tree. We found genetic correlations among phytochemistry of individual tree genotypes, the density of a galling herbivore, and the intensity of avian predation on these herbivores. We detected significant broad-sense heritability of these interactions that range from H(B)2 = 0.70 to 0.83. The genetic basis of these interactions tended to increase across trophic levels suggesting that small genetic changes in the cottonwood phenotype could have major consequences at higher trophic levels affecting species interactions and energy flow. These findings show a heritable basis to trophic-level interactions indicating that there is a significant genetic basis to community composition and energy flow that is predictable by plant genotype. Our data clearly link plant genetics to patterns of avian foraging and show that species interactions are important components of community heritability and ecosystem processes. Overall, these data support the hypothesis that evolution of plant traits can alter trophic-level interactions and community composition.

VL - 9 SN - 1461-023X UR - http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&DbFrom=pubmed&Cmd=Link&LinkName=pubmed_pubmed&LinkReadableName=Related%20Articles&IdsFromResult=16958871&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSumhttp://www.ncbi. IS - 1 ER -