The Recent Intrusion of Forests in the Ozarks

Beilmann, August P.; Brenner, Louis

doi:10.2307/2394637

Cited by 59 publications

(34 citation statements)

References 4 publications

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“…These regions differ significantly in terms of the time of occupation by collared lizards, and therefore in the likelihood of having attained equilibrium conditions, and in climatic and vegetative history. Because the main impediment to dispersal by collared lizards is vegetation (Templeton et al 1990;Templeton 1996), particularly dense forest undergrowth associated with fire prevention by European settlers (Beilmann and Brenner 1951;Kimmel and Probasco 1980;Cutter and Guyette 1994), regional differences in vegetative history, and fire frequency are important factors affecting regional differences in interactions between gene flow and drift.…”

Section: Testing the Modelmentioning

confidence: 99%

“…Furthermore, prior to European settlement of the Ozark Plateau, glades were often huge (Schoolcraft 1821;Beilmann and Brenner 1951), with presumably larger populations of collared lizards than currently reside in the area. Therefore, until the recent expansion of dense forest undergrowth in the southwestern Ozarks during the last century due to fire prevention by settlers (Kimmel and Probasco 1980), collared lizards were likely able to disperse locally between rather large neighboring populations.…”

Section: Testing the Modelmentioning

confidence: 99%

“…Prior to European settlement, the accumulation of dense undergrowth and the intrusion of cedars were prevented by recurrent and frequent fire, started either by lightning strikes or the deliberate actions of Native Americans (Guyette and McGinnes 1982;Cutter and Guyette 1994). These fires maintained large glade complexes in the area (Schoolcraft 1821;Beilmann and Brenner 1951) and most likely permitted extensive local dispersal between large lizard populations. Given sufficient time and stability of conditions, these processes might well have produced a pattern of isolation-by-distance as in Texas.…”

Section: •-El_mentioning

confidence: 99%

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Correlation of Pairwise Genetic and Geographic Distance Measures: Inferring the Relative Influences of Gene Flow and Drift on the Distribution of Genetic Variability

1999

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Abstract.-Attempts to relate estimates of regional F ST to gene flow and drift via Wright's (1931) equation F ST = 11(4Nm + 1) are often inappropriate because most natural sets of populations probably are not at equilibrium (McCauley 1993), as assumed by the island model upon which the equation is based, or ineffective because the influences of gene flow and drift are confounded in the product Nm. Evaluations of the association between genetic (F ST ) and geographic distances separating all pairwise populations combinations in a region allows one to test for regional equilibrium, to evaluate the relative influences of gene flow and drift on population structure both within and between regions, and to visualize the behavior of the association across all degrees of geographic separation. Tests of the model using micro satellite data from 51 populations of eastern collared lizards (Crotaphytus collaris collaris) collected from four distinct geographical regions gave results highly consistent with predicted patterns of association based on regional differences in various historical and ecological factors that affect the amount of drift and gene flow. The model provides a prerequisite for and an alternative to regional F ST analyses, which often simply assume regional equilibrium, thus potentially leading to erroneous and misleading inferences regarding regional population structure.Key words.-Correlations, Crotaphytus collaris, F-statistics, gene flow, genetic distance, Mantel's test, population structure, random genetic drift.Received March 24, 1998. Accepted June I, 1999.It is notoriously difficult to assess the individual effects of gene flow and drift on regional population structure. Traditional attempts to relate estimates of regional F ST to gene flow and drift via Wright's (1931) equation F ST = 1I(4Nm + 1) are often inappropriate because most natural sets of populations probably are not at equilibrium (McCauley 1993), as is assumed by the island model upon which the equation is based. Furthermore, the influences of gene flow and drift on regional population structure are confounded in the product Nm.In this paper we discuss a method that allows one to test for regional equilibrium before applying Wright's equation or other models that assume such a pattern. Although Nand m remain a product under this approach, it does permit evaluation of the relative historical influences of gene flow and drift on regional population structure by comparing the observed relationship between the genetic (F ST ; Reynolds et al. 1983) and geographic distances separating pairs of populations in a region (Nei 1972;Hartl and Clark 1989;Tilley et al. 1990) with those expected under a stepping-stone model of population structure (Kimura 1953;Malecot 1955;Kimura and Weiss 1964). Further refinement of the analysis is possible by taking into consideration various historical and ecological factors characteristic of a region as they pertain to the amount of drift and gene flow affecting the organisms under study. Finally, it is also p...

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Section: Testing the Modelmentioning

confidence: 99%

Section: Testing the Modelmentioning

confidence: 99%

Section: •-El_mentioning

confidence: 99%

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Correlation of Pairwise Genetic and Geographic Distance Measures: Inferring the Relative Influences of Gene Flow and Drift on the Distribution of Genetic Variability

1999

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“…After Euro-American settlement, fires were less frequent and burned smaller areas. The reduction in fire frequency resulted in replacement of large areas of grasslands by woodlands (Beilmann and Brenner 1951;Muir 1965;Pyne 1997).…”

Section: Fire Regime Characteristicsmentioning

confidence: 99%

“…One of the most aggressive woody species in the prairie is eastern redcedar. In the absence of fire this species could quickly become the dominant tree over much of the Ozark region (Beilmann and Brenner 1951). Cedar forests now occupy 6.4 million acres (2.6 million ha) in five Midwestern States, an increase of 113 percent during the last three decades (Schmidt and Leatherberry 1995).…”

Section: Prairiementioning

confidence: 99%

Wildland fire in ecosystems: effects of fire on flora

Brown¹,

Smith²

2000

300

156

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_____________________________________This state-of-knowledge review about the effects of fire on flora and fuels can assist land managers with ecosystem and fire management planning and in their efforts to inform others about the ecological role of fire. Chapter topics include fire regime classification, autecological effects of fire, fire regime characteristics and postfire plant community developments in ecosystems throughout the United States and Canada, global climate change, ecological principles of fire regimes, and practical considerations for managing fire in an ecosytem context.

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A reconceptualization of open oak and pine ecosystems of eastern North America using a forest structure spectrum

2018

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We present a reconceptualization of forests in eastern North America by differentiating the ecological characteristics of open oak (Quercus) and pine (Pinus) forests from closed successional and oldgrowth forests. Despite historical abundance of savannas and woodlands, the fundamental ecology of open forest ecosystems remains ill-defined when compared to either closed forests or grasslands. Open forests were characterized by simple internal stand structure consisting of a single stratum of variably spaced, often very old overstory trees and limited midstory, maintained by understory disturbance that controlled tree regeneration and allowed instead a taxonomically rich herbaceous groundlayer. In contrast, closed forests have dense woody growth throughout the vertical profile, limiting herbaceous plants. To provide further clarity about these ecosystems, we developed a canopy closure spectrum model dependent on the interactions between prevailing disturbance regimes of the historical and current eras, which affect either the tree understory (regeneration) or overstory, and tree traits of fire and shade tolerance. Recognition of different stand structures, disturbance regimes, and their interrelationships should expand understanding of open forests and limit ecological misunderstandings and restoration misapplications, thereby improving management of these once historically extensive ecosystems.

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The Recent Intrusion of Forests in the Ozarks

Cited by 59 publications

References 4 publications

Correlation of Pairwise Genetic and Geographic Distance Measures: Inferring the Relative Influences of Gene Flow and Drift on the Distribution of Genetic Variability

Correlation of Pairwise Genetic and Geographic Distance Measures: Inferring the Relative Influences of Gene Flow and Drift on the Distribution of Genetic Variability

Wildland fire in ecosystems: effects of fire on flora

A reconceptualization of open oak and pine ecosystems of eastern North America using a forest structure spectrum

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