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PHYLOGEOGRAPHY OF BUFO PUNCTATUS: LONG TERM EVOLUTION WITHIN THE WARM DESERTS OF NORTH AMERICA AND LATE QUATERNARY RANGE SHIFTING
Citation:
Jaeger, J R., B. R. Riddle, AND D F. Bradford. PHYLOGEOGRAPHY OF BUFO PUNCTATUS: LONG TERM EVOLUTION WITHIN THE WARM DESERTS OF NORTH AMERICA AND LATE QUATERNARY RANGE SHIFTING. Presented at Annual meeting of the American Society of Ichthyologists and Herpetologists, Kansas City, MO, July 3-8, 2002.
Impact/Purpose:
The primary objectives of this research are to:
Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;
Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;
Develop and validate multivariate models based on quantification studies;
Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;
Complete an initial draft (potentially web based) of a national landscape condition assessment.
This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.
Description:
Bufo punctatus, the red-spotted toad, is a widespread anuran of the warm-desert regions of western North America. This distribution makes this species ideal for evaluating biotic response to geotectonically and climatically mediated episodes of landscape transformation (e.g., earth history since the late Tertiary, and Pleistocene pluvial-interpluvial cycles). To identify phylogenetic patterns across the species range, we evaluated mitochondrial cytochrome b sequence data.
Analysis of these data reveals three evolutionary lineages (clades) with sequence divergences of about 7 - 7.5 %, after adjusting for intra-lineage variation. The geographic distribution of haplotypes within these three lineages are roughly concordant with the boundaries of the Baja California Peninsular Desert, a combined Sonoran-Mojave deserts region, and a Chihuahuan Desert-Colorado Plateau region. The general concordance between the distribution of these deeply- divergent haplotype lineages, desert regional boundaries, and lineage distributions in other codistributed taxa, indicate that B. punctatus (as currently recognized) probably evolved independently along with each of three core warm desert regions. These patterns indicate late Miocene-Pliocene divergence times between lineages. This cryptic divergence has implications for accurate recognition of taxa and definition of regional biotas. Contrasting within-lineage haplotype distributions across the three haplotype groups indicates differing responses to more recent (Pleistocene-Holocene) climatic variation within each of the main desert regions.