Effects of topoclimatic complexity on the composition of woody plant communities

AoB Plants. 2016 Aug 3;8. pii: plw049. doi: 10.1093/aobpla/plw049. Print 2016. . Oldfather MF1, Britton MN2, Papper PD3, Koontz MJ4, Halbur MM5, Dodge C5, Flint AL6, Flint LE6, Ackerly DD7. Author information 1 Department of Integrative Biology, University of California, Berkeley, CA 94720, USA meagan_oldfather@berkeley.edu. 2 Department of Biological Sciences and Bolus Herbarium, University of Cape Town, Private Bag, Rondebosch 7700, South Africa. 3 Department of Integrative Biology, University of California, Berkeley, CA 94720, USA. 4 Department of Plant Sciences, University of California Davis, Davis, CA 95618, USA. 5 Pepperwood Preserve, 2130 Pepperwood Preserve Road Santa Rosa, CA 95404, USA. 6 Water Resources Discipline, U.S. Geological Survey, Placer Hall, 6000 J Street, Sacramento, CA 95819, USA. 7 Department of Integrative Biology, University of California, Berkeley, CA 94720, USA Jepson Herbarium, University of California, Berkeley, CA 94720, USA. Abstract Topography can create substantial environmental variation at fine spatial scales. Shaped by slope, aspect, hill-position and elevation, topoclimate heterogeneity may increase ecological diversity, and act as a spatial buffer for vegetation responding to climate change. Strong links have been observed between climate heterogeneity and species diversity at broader scales, but the importance of topoclimate for woody vegetation across small spatial extents merits closer examination. We established woody vegetation monitoring plots in mixed evergreen-deciduous woodlands that spanned topoclimate gradients of a topographically heterogeneous landscape in northern California. We investigated the association between the structure of adult and regenerating size classes of woody vegetation and multidimensional topoclimate at a fine scale. We found a significant effect of topoclimate on both single-species distributions and community composition. Effects of topoclimate were evident in the regenerating size class for all dominant species (four Quercus spp., Umbellularia californica and Pseudotsuga menziesii) but only in two dominant species (Quercus agrifolia and Quercus garryana) for the adult size class. Adult abundance was correlated with water balance parameters (e.g. climatic water deficit) and recruit abundance was correlated with an interaction between the topoclimate parameters and conspecific adult abundance (likely reflecting local seed dispersal). However, in all cases, the topoclimate signal was weak. The magnitude of environmental variation across our study site may be small relative to the tolerance of long-lived woody species. Dispersal limitations, management practices and patchy disturbance regimes also may interact with topoclimate, weakening its influence on woody vegetation distributions. Our study supports the biological relevance of multidimensional topoclimate for mixed woodland communities, but highlights that this relationship might be mediated by interacting factors at local scales. Published by Oxford University Press on behalf of the Annals of Botany Company. KEYWORDS: California; climatic water deficit; community analyses; oak woodlands; topoclimate; woody vegetation PMID: 27339048 PMCID: PMC4972463 DOI: 10.1093/aobpla/plw049 Free PMC Article Share on FacebookShare on TwitterShare on Google+ Images from this publication.See all images (6)Free text Figure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6. LinkOut - more resources