Ecological Subregions: Sections and Subsections for the conterminous United States

Cleland, David T.; Freeouf, Jerry A.; Keys, James E.; Nowacki, Gregory J.; Carpenter, C.A.; McNab, W. Henry

doi:10.2737/wo-gtr-76d

Cited by 173 publications

(74 citation statements)

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“…Our study area encompassed approximately the northern half of Minnesota, USA (Fig. 1) within the Laurentian Mixed Forest Province (Cleland et al 2007). The study area is within the transition zone between temperate deciduous and boreal forest ecoregions, and the vegetative composition varies considerably (MNDNR 2017).…”

Section: Study Areamentioning

confidence: 99%

Ecological forecasts reveal limitations of common model selection methods: predicting changes in beaver colony densities

Johnson‐Bice

Ferguson

Erb

et al. 2020

Ecological Applications

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Over the past two decades, there have been numerous calls to make ecology a more predictive science through direct empirical assessments of ecological models and predictions. While the widespread use of model selection using information criteria has pushed ecology toward placing a higher emphasis on prediction, few attempts have been made to validate the ability of information criteria to correctly identify the most parsimonious model with the greatest predictive accuracy. Here, we used an ecological forecasting framework to test the ability of information criteria to accurately predict the relative contribution of density dependence and density-independent factors (forage availability, harvest, weather, wolf [Canis lupus] density) on inter-annual fluctuations in beaver (Castor canadensis) colony densities. We modeled changes in colony densities using a discrete-time Gompertz model, and assessed the performance of four models using information criteria values: density-independent models with (1) and without (2) environmental covariates; and density-dependent models with (3) and without (4) environmental covariates. We then evaluated the forecasting accuracy of each model by withholding the final one-third of observations from each population and compared observed vs. predicted densities. Information criteria and our forecasting accuracy metrics both provided strong evidence of compensatory density dependence in the annual dynamics of beaver colony densities. However, despite strong within-sample performance by the most complex model (density-dependent with covariates) as determined using information criteria, hindcasts of colony densities revealed that the much simpler density-dependent model without covariates performed nearly as well predicting out-of-sample colony densities. The hindcast results indicated that the complex model over-fit our data, suggesting that parameters identified by information criteria as important predictor variables are only marginally valuable for predicting landscapescale beaver colony dynamics. Our study demonstrates the importance of evaluating ecological models and predictions with long-term data and revealed how a known limitation of information criteria (over-fitting of complex models) can affect our interpretation of ecological dynamics. While incorporating knowledge of the factors that influence animal population dynamics can improve population forecasts, we suggest that comparing forecast performance metrics can likewise improve our knowledge of the factors driving population dynamics.

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Section: Study Areamentioning

confidence: 99%

Ecological forecasts reveal limitations of common model selection methods: predicting changes in beaver colony densities

Johnson‐Bice

Ferguson

Erb

et al. 2020

Ecological Applications

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“…Average precipitation varies from 10 to 50 inches per year, increasing from west to east. The region's forests occur in portions of the Prairie, Warm Continental, Hot Continental, and Subtropical ecological divisions, and encompass all or part of 16 ecological provinces (Cleland et al 2007). For this study, provinces were grouped into four ecological subdivisions: Central/Plains, Lake, Mid-Atlantic, and New England.…”

Section: Mapping Efforts In 1947mentioning

confidence: 99%

“…-Number of sample locations on forest land, by ecological subdivision and province(Cleland et al 2007), Midwest and Northeast.…”

mentioning

confidence: 99%

Subcontinental-scale patterns of large-ungulate herbivory and synoptic review of restoration management implications for midwestern and northeastern forests

McWilliams

Westfall

Brose

et al. 2018

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Browse of forest understory vegetation by deer and other large ungulates alters ecosystem processes, making it difficult to regenerate forest land in herbivory-stressed areas. Seventy years ago, Aldo Leopold identified problem areas in the United States where overpopulation of whitetailed deer (Odocoileus virginianus) was likely to lead to overbrowsing of nutritive plants. Species of plants with little or no nutritive value would thereby gain a competitive advantage. Recent measurements of browse impacts on regionwide forest inventory plots in the midwestern and northeastern United States provide the opportunity to review the work of Leopold and others. A visualization of the probability of browse impact levels that warrant consideration during regeneration planning is presented for comparison to historical maps.Currently, 59 percent of the 182.4 million acres of forest land inventoried in the Midwest and Northeast was estimated to have moderate or high browse impacts. The Mid-Atlantic region had the highest proportion of forest land with moderate or high browse impacts (79 percent). The oak/hickory (Quercus/Carya) and maple/beech/birch (Acer/Fagus/Betula) forest-type groups each had percentages of forest land with moderate or high impacts above the regional average, 69 percent and 65 percent, respectively. The problem areas described by Leopold and others persist

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“…I subdivided the eastern region into the central east and southeast ecoregions (Figure 2; hereafter each of the three extents is considered a region). The regions generally followed ecological divisions, but I moved the forested Oklahoma Cross Timbers and Texas savannas from the central grasslands to eastern forests (Cleland et al, 2007 .8, 5.8-11.6, 11.6-17.4, and >17.4 deer/km 2 . Spatial units were by county or divisions of the county.…”

Section: Me Thodsmentioning

confidence: 99%

Addressing regional relationships between white‐tailed deer densities and land classes

Hanberry

2021

Ecology and Evolution

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White-tailed deer (Odocoileus virginianus) populations have recovered to about 30 million animals in the United States, but land cover has changed during the interval of recovery. To address the relationship between deer densities and current land cover at regional scales, I applied random forests and extreme gradient boosting classifiers to model low and high deer density classes, at two different thresholds (5.8 and 11.6 deer/km 2 ), and land classes in three regions during approximately 2003. For low and high deer density classes divided at 5.8 deer/km 2 , deciduous broadleaf forest overall was the most influential and positive variable in the central east and central regions and crop and pasture were the most influential and negative variables in the southeast region. Deer density increased with area of deciduous and mixed forests, woody wetlands, and shrub in all regions. Deer density decreased with area of crop, developed open space, and developed low and medium residential density in all regions. For density classes divided at 11.6 deer/km 2 , deer density had the strongest relationship with woody wetlands in the central east region, mixed and deciduous forest in the southeast region, and woody wetlands and herbaceous vegetation in the central region. Deer density increased with deciduous and mixed forests, woody wetlands, and shrub in all regions. Conversely, deer density decreased with herbaceous vegetation, crop, and developed low residential densities in all regions. Therefore, at regional scales, deer overall occurred at greater densities in forests and woody wetlands and lower densities in agricultural and residential development, which did not appear to support more deer. Deer preference for forests does result in damage to forest products, but alternatively, some may consider that deer provide important socioeconomic and ecological services by reducing number of small trees, particularly in the absence of other disturbances that historically controlled tree biomass.

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Ecological Subregions: Sections and Subsections for the conterminous United States

Cited by 173 publications

References 0 publications

Ecological forecasts reveal limitations of common model selection methods: predicting changes in beaver colony densities

Ecological forecasts reveal limitations of common model selection methods: predicting changes in beaver colony densities

Subcontinental-scale patterns of large-ungulate herbivory and synoptic review of restoration management implications for midwestern and northeastern forests

Addressing regional relationships between white‐tailed deer densities and land classes

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