OOS 15
Evaluating The Dynamics Of Tree Species Range Limits Under Climate Change For Sustaining Biodiversity

Wednesday, August 7, 2013: 8:00 AM-11:30 AM
101A, Minneapolis Convention Center
Anantha Prasad, Northern Research Station, USDA Forest Service
Louis Iverson, Northern Research Station, USDA Forest Service
Species range limits are dynamic and subject to local, regional and global processes that encompass ecological and evolutionary phenomena. Genetic constraints on adaptation and biogeographic constraints on colonization of suitable habitats are the main drivers of species range limits. Understanding how these processes will play out at the range limits is critical to addressing the question whether species can adapt, migrate or go extinct under rapid climate change. Given the interplay of evolutionary and ecological factors, sustaining biodiversity in an era impacted by rapid climate change will require a merging of disciplines to study the various processes involved. The purpose of this organized session is to assess how these processes will affect the distribution of tree species at the range margins and to show how recent improvements in data and models can help manage for biodiversity and ecosystem functionality. There are three main factors that influence species range boundaries. A) Historical & evolutionary mechanisms: Species niches historically have remained relatively constant in the face of historical climatic change (niche conservatism) causing them to migrate in line with their native climatic-niches. Nevertheless many species migration involved some degree of adaptive evolutionary change during the Holocene. For example, gene-flow from pre-adapted range-centers can aid tree species adaptation; low levels of genetic variation in ecologically important traits due to genetic drift and low mutational input can hamper it. In contrast, the trailing edge does not receive pre-adapted genes – therefore adaptation is dependent on local variation and the populations are subjected to more intense competition and demographic effects that could result in range contraction. B) Source-sink dynamics: Spatial heterogeneity in the distribution of tree species due to geographic-environmental-stochastic processes has led to spatial variation in sources and sinks that could enable or impede range expansion in the temporal dimension. These processes are better evaluated at macro-ecological scales. C) Ecological processes: There is a host of ecological factors that influence tree species abundance like density dependent demography, Allee effects, smaller-scale metapopulation dynamics, intraspecific/interspecific competition/mutualism, parasitism and herbivory. These processes impact species abundance at more local scales and could be important in maintaining or expanding range margins.
8:00 AM
 Combined impacts of rarity and anthropogenic habitat fragmentation on genetic diversity at species range-limits
Jason McLachlan, University of Notre Dame; Candice Y. Lumibao, University of Notre Dame
8:40 AM
 Looking back to see ahead: Considering genetic divergence within tree species to anticipate responses to climate change
Kevin M. Potter, North Carolina State University; William Hargrove, USDA Forest Service, Eastern Forest Environmental Threat Assessment Center; Valerie D. Hipkins, USDA Forest Service; Robert E. Means, Bureau of Land Management; Robert M. Jetton, North Carolina State University
9:00 AM
 The impact of biotic interactions on seedling recruitment during tree range expansion
Daniel W. Katz, University of Michigan; Inés Ibáñez, University of Michigan
9:20 AM
 Processes at work on North American tree species range edges have implications for the predictability of their movements under climate change
Volker Bahn, Wright State University; Stephen N. Matthews, The Ohio State University; Xavier Morin, CNRS
9:40 AM
9:50 AM
 Incorporating range position and temporal stability of projected changes in tree species habitats to assess regional climate change vulnerability
Stephen N. Matthews, The Ohio State University; Louis Iverson, Northern Research Station, USDA Forest Service; Anantha Prasad, Northern Research Station, USDA Forest Service; Matthew P. Peters, Northern Research Station, USDA Forest Service
10:50 AM
 Demographically driven distribution models; Advantages of using integral projection models to incorporate demography into species distribution models
Cory Merow, Smithsonian Environmental Research Center; Andrew M. Latimer, University of California Davis; Adam M. Wilson, Yale University; Sean McMahon, Smithsonian Tropical Research Institute; John A. Silander, University of Connecticut
11:10 AM
 Climatic and biotic velocities for woody taxa distributions over the last 16,000 years in eastern North America
Alejandro Ordonez, Aarhus University; John W. Williams, University of Wisconsin-Madison