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| Lepofsky, Dana; Simon Fraser University; dlepofsk@sfu.ca; Heyerdahl, Emily K; USDA Forest Service; eheyerdahl@fs.fed.us; Lertzman, Ken; Simon Fraser University; lertzman@sfu.ca; Mierendorf, Bob; North Cascades National Park Service Complex; Bob_Mierendorf@nps.gov. |
| The recent encroachment of woody species threatening many western North American meadows has been attributed to diverse factors. We used a suite of methods in Chittenden Meadow, southwestern British Columbia, Canada, to identify the human, ecological, and physical factors responsible for its historical dynamics and current encroachment by woody vegetation. We evaluated three hypotheses about the origin and processes maintaining the meadow: the meadow is (1) of recent human origin; (2) of ancient human origin, maintained by aboriginal burning; and (3) of ancient non-human origin, not maintained by aboriginal burning. Our data supported the idea that the meadow had ancient non-human origins and its recent history and current status have resulted from... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Anthropogenic influence; Archaeology; British Columbia; Cascade Range; Chittenden Meadow; Climate change; Dendrochronology; Fire suppression; Historical dynamics; Meadows; Ponderosa pine; Tree encroachment. |
| Ano: 2003 |
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| Lertzman, Ken; Simon Fraser University; lertzman@sfu.ca; Gavin, Daniel; Department of Plant Biology, University of Illinois, Urbana, IL 61801, USA; dgavin@life.uiuc.edu; Hallett, Douglas; Center for Environmental Sciences & Quaternary Sciences Program, Northern Arizon; Douglas.Hallett@NAU.EDU; Brubaker, Linda; College of Forest Resources, University of Washington, Seattle, WA 98195, USA; lbru@u.washington.edu; Lepofsky, Dana; Simon Fraser University; dlepofsk@sfu.ca; Mathewes, Rolf; Department of Biological Sciences, Simon Fraser University; mathewes@sfu.ca. |
| Coastal temperate rainforests from southeast Alaska through to southern Oregon are ecologically distinct from forests of neighboring regions, which have a drier, or more continental, climate and disturbance regimes dominated by fires. The long-term role of fire remains one of the key outstanding sources of uncertainty in the historical dynamics of the wetter and less seasonal forests that dominate the northerly two thirds of the rainforest region in British Columbia and Alaska. Here, we describe the long-term fire regime in two forests on the south coast of British Columbia by means of 244 AMS radiocarbon dates of charcoal buried in forest soils. In both forests, some sites have experienced no fire over the last 6000 years and many other sites have... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Clayoquot Sound; Fraser Valley; Coastal temperate rainforests; Fire intervals; Long-term fire regime; Soil carbon storage; Soil charcoal; Sub-alpine forest; Time-since-fire. |
| Ano: 2002 |
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| Sutherland, Glenn D; University of British Columbia; gsland@interchg.ubc.ca; Harestad, Alton S; Simon Fraser University; harestad@sfu.ca; Price, Karen; Simon Fraser University; kprice@futurenet.ca; Lertzman, Ken; Simon Fraser University; lertzman@sfu.ca. |
| Natal dispersal is a process that is critical in the spatial dynamics of populations, including population spread, recolonization, and gene flow. It is a central focus of conservation issues for many vertebrate species. Using data for 77 bird and 68 mammal species, we tested whether median and maximum natal dispersal distances were correlated with body mass, diet type, social system, taxonomic family, and migratory status. Body mass and diet type were found to predict both median and maximum natal dispersal distances in mammals: large species dispersed farther than small ones, and carnivorous species dispersed farther than herbivores and omnivores. Similar relationships occurred for carnivorous bird species, but not for herbivorous or omnivorous ones.... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Allometric scaling; Birds; Body mass; Comparative analysis; Connectedness; Diet type; Habitat alterations; Life history; Mammals; Movements; Natal dispersal distances; Probability density function. |
| Ano: 2000 |
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