Sedgwick Reserve

09 May, 05 AM - 11 May, 05 AM

Microtus californicus has been investigated from numerous perspectives including ecology, reproduction, and behavior. Few of these studies have been inclusive of wide ranging populations, thus the parameters estimated may only reflect local conditions. One exception is the seminal work on M. californicus taxonomy (Kellogg, 1920). Subsequent refinements to Kellogg?s taxonomy have also incorporated samples across the range of the species. Another example of a broad study is that of Gill (1980) who noted genetic and morphologic differences between northern and southern California populations. The impetus behind my study was partly to study the genetic architecture of this species to investigate whether local ecological studies apply to a homogenous species, or if significant population structure may warrant further study in each evolutionarily significant unit. A second reason to investigate this species is to investigate shared phylogeographic history between this species and the other species in California that have already been investigated. A third was to investigate congruence between subspecific taxonomy and underlying genetic structure. Thus far, I have uncovered two substantially differentiated clades with mitochondrial DNA. These clades are nearly as divergent as other pairs of well-recognized species of voles. The two clades come into contact in the Mountains North of Ventura as well as along the coast in and near Goleta, west to Tajiguas landfill. A nuclear marker indicates gene flow is occurring among these individuals. Gill's (1980) study of divergence between north and south vole populations was done without prior knowledge of the underlying mtDNA divergence. Her work showed that there was fixation in allozyme markers, significant morphological divergence in the skull, and reproductive barriers. Specifically on the latter point, Gill recorded aggression between northern and southern populations, reduced fertility in creation of hybrids (male hybrids did not produce sperm), and reduced fertility in further back crosses (Gill, 1980). Thus it is extremely interesting to find sympatry of the northern and southern clades. These could turn out to be excellent laboratories for future study. I would like to secure voles at Sedgwick in hopes that they might also be mixed populations. Sedgwick could be an ideal setting to investigate the zone of contact between these incipient species. Use of Sedgwick at this time is only to live trap and remove about 10 voles (and a few other representative mammal species to include in phylogeographic studies). Future work could include longer stays, behavioral observations, mark and recapture, etc. The current work is only to map the extent of the two clades and find localities with mixed populations. I only need to set Sherman live traps and have room to camp and prepare museum specimens. I can be largely self-sufficient.

Visit #1273 @Sedgwick Reserve

Approved

Under Project # 1065 | Research

Phylogeography of California voles

research_scientist - University of California, Berkeley

Reservation Members(s)

Chris Conroy May 9 - 11, 2003 (3 days)

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