Origin of the Driftless Area by subglacial drainage - a new hypothesis

Hobbs, H.C.

doi:10.1130/0-8137-2337-x.93

Cited by 18 publications

(24 citation statements)

References 15 publications

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“…The region lacks glacial drift characteristic of retreating ice, hence its name, and there has been extensive debate as to whether it remained unglaciated at the LGM (Jacobs et al. , 1997; Hobbs, 1999). Phylogeographic (Jaramillo‐Correa et al.…”

Section: Discussionmentioning

confidence: 99%

Phylogeographic analysis of North American populations of the parasitic herbaceous plant Monotropa hypopitys L. reveals a complex history of range expansion from multiple late glacial refugia

Beatty

Provan²

2011

Journal of Biogeography

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Aim We carried out a phylogeographic study across the range of the herbaceous plant species Monotropa hypopitys L. in North America to determine whether its current disjunct distribution is due to recolonization from separate eastern and western refugia after the Last Glacial Maximum (LGM). Location North America: Pacific Northwest and north-eastern USA/south-eastern Canada. Methods Palaeodistribution modelling was carried out to determine suitable climatic regions for M. hypopitys at the LGM. We analysed between 155 and 176 individuals from 39 locations spanning the species' entire range in North America. Sequence data were obtained for the chloroplast rps2 gene (n = 168) and for the nuclear ITS region (n = 158). Individuals were also genotyped for eight microsatellite loci (n = 176). Interpolation of diversity values was used to visualize the range-wide distribution of genetic diversity for each of the three marker classes. Minimum spanning networks were constructed showing the relationships between the rps2 and ITS haplotypes, and the geographical distributions of these haplotypes were plotted. The numbers of genetic clusters based on the microsatellite data were estimated using Bayesian clustering approaches. Results The palaeodistribution modelling indicated suitable climate envelopes for M. hypopitys at the LGM in both the Pacific Northwest and south-eastern USA. High levels of genetic diversity and endemic haplotypes were found in Oregon, the Alexander Archipelago, Wisconsin, and in the south-eastern part of the species' distribution range. Main conclusions Our results suggest a complex recolonization history for M. hypopitys in North America, involving persistence in separate eastern and western refugia. A generally high degree of congruence between the different marker classes analysed indicated the presence of multiple refugia, with at least two refugia in each area. In the west, putative refugia were identified in Oregon and the Alexander Archipelago, whereas eastern refugia may have been located in the southern part of the species' current distribution, as well as in the 'Driftless Area'. These findings are in contrast to a previous study on the related species Orthilia secunda, which has a similar disjunct distribution to M. hypopitys, but which appears to have recolonized solely from western refugia.Peer reviewe

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Section: Discussionmentioning

confidence: 99%

Phylogeographic analysis of North American populations of the parasitic herbaceous plant Monotropa hypopitys L. reveals a complex history of range expansion from multiple late glacial refugia

Beatty

Provan²

2011

Journal of Biogeography

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“…1). This geologically unique region was circumvented by ice during the most recent glaciation (Hobbs, 1999) and is characterized by a loess-capped plateau and steep ravines formed by several large rivers that flow through the region. Prairie soils can be found on the ridges, with thick silt loams (loess) covering cherty residuum, with an underlying dolomite bedrock, and silt loam over sandstone on valley walls found in some parts of the region (Albert, 1995).…”

Section: Study Areamentioning

confidence: 99%

Forest change in the Driftless Area of the Midwest: From a preferred to undesirable future

Knoot

Shea

Schulte

et al. 2015

Forest Ecology and Management

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In the midwestern and eastern U.S., oaks (Quercus spp.) have been a dominant component of forests for at least the last 10,000 years, providing vital habitat for numerous wildlife and plant species that have adapted to oak forest conditions. However, the current state of these oak systems, in which there has been a general lack of successful oak regeneration and recruitment and an increase in the relative dominance of mesophytic species, may be nearing critical thresholds. If reached, restoring oak systems through natural regeneration and other methods, such as prescribed fire, may become especially challenging if not impossible. An understanding of spatial variation in oak dominance over time can inform and potentially improve the efficacy of intervention strategies. Using Public Land Survey and Forest Inventory and Analysis (FIA) inventories, we evaluated changes in the composition of timberland across ecoregional subsections in the Driftless Area of the Midwest at three time periods (pre-settlement 1800s, 1990s, and 2000s). We identified an overall decrease in oak dominance, and particularly dominance of the white oak (Quercus alba L., Q. macrocarpa Michx., and Q. bicolor Willd.) species group since the presettlement era, and an increase in other eastern soft hardwoods. Within the last 20 years, both the red oak (Q. rubra L., Q. ellipsoidalis E.J. Hill and Q. velutina Lam.) and white oak species groups decreased in dominance, with an increase in hard maple-basswood (A. saccharum Marsh., A. nigra L., and Tilia americana L.) species group dominance, indicating further mesophication of forests in the region. However, we found a notable decrease in hard maple-basswood relative dominance within the small diameter class across most of the regions within the last 10-20 years, with an increase in dominance of other, non-oak, species. Our findings complement qualitative evidence from interviews with natural resource professionals from the region and offer further information on the potential for forest conversion to ''undesirable'' forest conditions, as identified as a source of concern by some professionals. There was spatial variation in these trends, however, with some pronounced differences across adjacent state boundaries. The variation in forest change across state boundaries suggests the role of state-level socioeconomic and policy factors in affecting forest conditions, and thus the potential for a targeted and timely approach to promoting preferred pathways of change. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. a b s t r a c tIn the midwestern and eastern U.S., oaks (Quercus spp.) have been a dominant component of forests for at least the last 10,000 years, providing vital habitat for numerous wildlife and plant species that have adapted to oak forest conditions. However, the current state of these oak systems, in which there has been a general lack of successful oak reg...

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“…This 55,000 km2 region is composed of portions of southwestern Wisconsin, southeastern Minnesota, northeastern Iowa, and northwestern Illinois (Figure 1) not covered by glacial ice during the Late Wisconsin glaciation of the Quaternary Period (Hobbs 1999). Because it escaped this most recent glacial advance, the region has high levels of topographic variation and contains a distinctive array of plant communities and several preglacial relict species absent from surrounding regions (Curtis 1971, USFWS 2006.…”

Section: Meters Riversmentioning

confidence: 99%

Reconstructing Vegetation Past: Pre-Euro-American Vegetation for the Midwest Driftless Area, USA

Shea¹,

Schulte

Palik

2014

Ecological Restoration

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Historical reference conditions provide important context for creating ecological restoration and management plans. The U.S. 19th Century Public Land Survey (PLS) records provide extensive ecological information for constructing such reference conditions. We used PLS records to reconstruct pre-Euro-American tree species cover class and vegetation structure types for the Midwest Driftless Area, a 55,000 km2 region currently experiencing multiple conservation threats. We related cover classes to soil texture, topographic roughness, and distance from waterway. Our analyses revealed that the landscape of the Driftless Area was mostly composed of savanna, with two large patches of closed forest and smaller, scattered patches of closed forest, open woodland, and prairie. The Driftless Area was heavily dominated by a variety of oak communities, with bur (Quercus macrocarpa), white (Q. alba), and black (Q. velutina) oak by far the most dominant species across the region. A variety of non-oak communities occurred within the closed forest patches, along rivers, or in smaller areas near the periphery of the region. The prevalence of savanna and oak communities indicates that fire played a key role in mediating historical landscape patterns and ecosystem processes in the region. Variation in soil texture, topographic roughness, and distance from waterways additionally contributed to the diversity of cover classes present prior to Euro-American settlement. Restoration practitioners can use our reconstructions to inform regional and site-specific restoration planning. Because oaks tend to be foundational species within ecosystems and are currently in decline throughout the Driftless Area, restoration activities that encourage these species are urgently needed. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. ABSTRACTHistorical reference conditions provide important context for creating ecological restoration and management plans. The U.S. 19th Century Public Land Survey (PLS) records provide extensive ecological information for constructing such reference conditions. We used PLS records to reconstruct pre-Euro-American tree species cover class and vegetation structure types for the Midwest Driftless Area, a 55,000 km2 region currently experiencing multiple conservation threats. We related cover classes to soil texture, topographic roughness, and distance from waterway. Our analyses revealed that the landscape of the Driftless Area was mostly composed of savanna, with two large patches of closed forest and smaller, scattered patches of closed forest, open woodland, and prairie. The Driftless Area was heavily dominated by a variety of oak communities, with bur (Quercus macrocarpa), white (Q. alba), and black (Q. velutina) oak by far the most dominant species across the region. A variety of non-oak communities occurred within the closed forest patches, along rivers, or in smaller areas near the ...

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Origin of the Driftless Area by subglacial drainage - a new hypothesis

Cited by 18 publications

References 15 publications

Phylogeographic analysis of North American populations of the parasitic herbaceous plant Monotropa hypopitys L. reveals a complex history of range expansion from multiple late glacial refugia

Phylogeographic analysis of North American populations of the parasitic herbaceous plant Monotropa hypopitys L. reveals a complex history of range expansion from multiple late glacial refugia

Forest change in the Driftless Area of the Midwest: From a preferred to undesirable future

Reconstructing Vegetation Past: Pre-Euro-American Vegetation for the Midwest Driftless Area, USA

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