TY - JOUR T1 - Local biotic adaptation of trees and shrubs to plant neighbors. JF - Okios Y1 - 2017 A1 - Grady, K.C. A1 - Wood, T. E. A1 - Kolb, T. E. A1 - Hersch-Green, E. A1 - Shuster, S.M. A1 - Gehring, C. A. A1 - Hart, S.C. A1 - Allan, G.J. A1 - T. G. Whitham AB -

Natural selection as a result of plant–plant interactions can lead to local biotic adaptation. This may occur where species frequently interact and compete intensely for resources limiting growth, survival, and reproduction. Selection is demonstrated by comparing a genotype interacting with con‐ or hetero‐specific sympatric neighbor genotypes with a shared site‐level history (derived from the same source location), to the same genotype interacting with foreign neighbor genotypes (from different sources). Better genotype performance in sympatric than allopatric neighborhoods provides evidence of local biotic adaptation. This pattern might be explained by selection to avoid competition by shifting resource niches (differentiation) or by interactions benefitting one or more members (facilitation). We tested for local biotic adaptation among two riparian trees, Populus fremontii and Salix gooddingii, and the shrub Salix exigua by transplanting replicated genotypes from multiple source locations to a 17 000 tree common garden with sympatric and allopatric treatments along the Colorado River in California. Three major patterns were observed: 1) across species, 62 of 88 genotypes grew faster with sympatric neighbors than allopatric neighbors; 2) these growth rates, on an individual tree basis, were 44, 15 and 33% higher in sympatric than allopatric treatments for P. fremontii, S. exigua and S. gooddingii, respectively, and; 3) survivorship was higher in sympatric treatments for P. fremontii and S. exigua. These results support the view that fitness of foundation species supporting diverse communities and dominating ecosystem processes is determined by adaptive interactions among multiple plant species with the outcome that performance depends on the genetic identity of plant neighbors. The occurrence of evolution in a plant‐community context for trees and shrubs builds on ecological evolutionary research that has demonstrated co‐evolution among herbaceous taxa, and evolution of native species during exotic plants invasion, and taken together, refutes the concept that plant communities are always random associations.

VL - 126 UR - https://onlinelibrary.wiley.com/doi/full/10.1111/oik.03240 IS - 4 ER - TY - JOUR T1 - Local-Scale Drought Adaptation of Ponderosa Pine Seedlings at Habitat Ecotones JF - Forest Science Y1 - 2016 A1 - TE Kolb A1 - Grady,KC A1 - Mcettrick,MP A1 - Herrero,A AB - Abstract Understanding the magnitude and pattern of intraspecific variation in tree adaptation to drought is needed to evaluate forest capacity to respond to climate change and for management planning. This understanding is important for species growing at ecotonal sites near the trailing edge of their geographic range where impacts of climate warming are predicted to be most severe. We used a greenhouse common garden to investigate phenotypic variations in growth, drought-adaptive structural traits (e.g., wood specific gravity, shoot-root ratio, and specific leaf area), and survival during experimental drought in seedlings of ponderosa pine (Pinus ponderosa Doug. Ex. Laws) sampled from 17 sites in northern Arizona over gradients of elevation, precipitation, and soil parent material. Phenotypic variation was significant in most seedling traits, and the most variation occurred among maternal families within site populations. Growth rate was negatively correlated with wood specific gravity. The large amount of phenotypic variation within populations suggests the potential for future evolution of stress tolerance in trailing-edge populations. The strongest geographic pattern in phenotypic variation was a negative relationship between seedling biomass allocation to roots and precipitation of the population site. Families with the longest survival in a lethal drought experiment tended to come from low-elevation, drier sites. VL - 62 UR - http://www.ingentaconnect.com/content/saf/fs/pre-prints/content-forsci16049 ER - TY - JOUR T1 - Long-term thinning alters ponderosa pine reproduction in northern Arizona. JF - Forest Ecology and Management Y1 - 2016 A1 - Flathers,KN A1 - TE Kolb A1 - Bradford,JB A1 - Waring,KM A1 - Moser,WK VL - 374 N1 - [Original String]:Flathers, K. N., Kolb, T. E., Bradford, J. B. Waring, K. M. and Moser, W. K. (2016). Long-term thinning alters ponderosa pine reproduction in northern Arizona. Forest Ecology and Management 374:154-165. ER -