نتایج جستجو برای: historical landscape

تعداد نتایج: 174233  

2009
Douglas J. Shinneman Meredith W. Cornett Brian J. Palik

Restoring altered forest landscapes toward their ranges of natural variability (RNV) may enhance ecosystem sustainability and resiliency, but such efforts can be hampered by complex land ownership and management patterns. We evaluated restoration potential for southern-boreal forests in the 2.1 million ha Border Lakes Region of northern Minnesota (U.S.A.) and Ontario (Canada), where spatially d...

2012
Joy B. Zedler James M. Doherty Nicholas A. Miller

Policy to guide ecological restoration needs to aim toward minimizing the causes of ecosystem degradation; where causes cannot be eliminated or minimized, policy needs to shift toward accommodating irreversible landscape alterations brought about by climate change, nitrogen deposition, altered hydrology, degraded soil, and declining biodiversity. The degree to which lost diversity and ecosystem...

2015
Daniel A. Sarr Robert W. Van Kirk Erik S. Jules

For over a century, increases in the abundance of woody plants in savannas have been occurring worldwide in a process known as encroachment. Encroachment into savannas is a significant management concern because it affects the unique values associated with savanna systems, including high levels of both taxonomic and landscape diversity. Improving methods for reconstructing encroachment patterns...

2008
Kelly O. Maloney Jack W. Feminella Richard M. Mitchell Stephanie A. Miller Patrick J. Mulholland Jeffrey N. Houser

The concept of landscape legacies has been examined extensively in terrestrial ecosystems and has led to a greater understanding of contemporary ecosystem processes. However, although stream ecosystems are tightly coupled with their catchments and, thus, probably are affected strongly by historical catchment conditions, few studies have directly examined the importance of landuse legacies on st...

2007
Anne McClintock

perience pushed a little (and only very little) beyond the actual facts of the case."2 Yet, there is equally a highly important sense in which the Congo of Heart of Darkness is not the Congo of any history book. That is to say, the apparently innocent activity of source-hunting masks a number of serious methodological problems. Perhaps the most important of these can be broached by invoking Con...

2016
Yong-Hua Zhang Ian J. Wang Hans Peter Comes Hua Peng Ying-Xiong Qiu

Examining how historical and contemporary geographic and environmental factors contribute to genetic divergence at different evolutionary scales is a central yet largely unexplored question in ecology and evolution. Here, we examine this key question by investigating how environmental and geographic factors across different epochs have driven genetic divergence at deeper (phylogeographic) and s...

Journal: :The Journal of heredity 2015
Genevieve Metzger Anahi Espindola Lisette P Waits Jack Sullivan

Contemporary and historical processes interact to structure genetic variation, however discerning between these can be difficult. Here, we analyze range-wide variation at 13 microsatellite loci in 2098 Rocky Mountain tailed frogs, Ascaphus montanus, collected from 117 streams across the species distribution in the Inland Northwest (INW) and interpret that variation in light of historical phylog...

Journal: :Environmental management 2009
Heida L Diefenderfer Kathryn L Sobocinski Ronald M Thom Christopher W May Amy B Borde Susan L Southard John Vavrinec Nichole K Sather

Planners are being called on to prioritize marine shorelines for conservation status and restoration action. This study documents an approach to determining the management strategy most likely to succeed based on current conditions at local and landscape scales. The conceptual framework based in restoration ecology pairs appropriate restoration strategies with sites based on the likelihood of p...

2008
Amanda M. Thomson Ian A. Simpson

Defining historic grazing pressures and rangeland management is vital if early landscape threshold crossing and long–term trajectories of landscape change are to be properly understood. In this paper we use a new environmental simulation model, Búmodel, to assess two contrasting historical grazing landscapes in Mývatnssveit Iceland for two key periods—the colonization period (ca. Landnám, A.D. ...

2013
Carlo Ricotta Maria Laura Carranza

In this paper, we apply a special application of the Rao quadratic diversity for multiscale analysis of land use changes in a mixed agricultural-forest landscape in Central Italy. The proposed approach is similar to a block-size analysis of compositional diversity for which a given landscape is overlaid with a series of square grids composed of increasingly larger boxes. The combination of land...

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