Local environmental features can shape hybrid zone dynamics when hybrids are bounded by ecotones or when patchily distributed habitat types lead to a corresponding mosaic of genotypes. We investigated the role of marsh-level characteristics in shaping a hybrid zone between two recently diverged avian taxa - Saltmarsh (Ammodramus caudacutus) and Nelson's (A. nelsoni) sparrows. These species occu...

when two species of animals overlap geographically, the differences between them are accentuated in the zone of sympatry and weakened or lost entirely in the parts of their ranges outside this zone. The characters involved in this dual divergence-convergence pattern may be morphological, ecological, behavioral, or physiological. [The SCI® indicates that this paper has been cited in over 255 pub...

Two new species of the genus Melanoplus Stål 1873 are described. M. trachodes n. sp., and M. parvus n. sp., both of which are endemic to the cool-temperate mountains of the Eastern Sierra Madre (ESM) in northeastern Mexico. Their habitat represents a transition zone between the ESM and the semiarid High Plateau Biogeographic provinces. This transition zone is characterized by an elevation range...

We assembled a molecular phylogeny for the arid-zone members of the Egernia whitii species group to test Pianka's [Zoogeography and speciation of Australian desert lizards: an ecological perspective, Copeia (1972) 127-145] hypothesis that habitat specificity to the three major arid-zone vegetation communities is the primary cause of lizard speciation within the arid interior of Australia. This ...

Upon the completion of a series of investigations in southeastern Washington and adjacent Idaho (23), in which there was found to be a direct relation between the available water content of the soil and the evaporating power of the air as succession progressed from gl'assland through scrub to forest, the senior writer moved to Minneapolis, Minnesota. Here such excellent conditions of prairie in...

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