Geology topics

R.F. Keim

Publications and source records attributed to R.F. Keim.

4 recordsLinked to original sources

USGS2022

Influences of channel and floodplain modification on expansion of woody vegetation into Catahoula Lake, Louisiana, USA

Ecosystem structure of wetlands in managed floodplains depends on hydrological processes controlled by geomorphology and water management. Overlapping effects of direct modifications and geomorphic adjustments to management can combine to trigger changes to floodplain ecosystem structure. We examined the case of woody vegetation encroaching into the depressional Catahoula Lake, Louisiana, in the context of regional hydrologic and geomorphic modification in the floodplain of the Mississippi River. Historical aerial photographs indicated woody encroachment into Catahoula Lake for at least 80 years, and the rate of expansion has increased in recent decades. Historical stage analysis revealed that the downstream Red–Atchafalaya–Mississippi River system controls the lower limit of the lake water level when the large rivers are high, but channel enlargement and other hydrological changes there have reduced the frequency of backwater flooding by 42% since 1880. In addition, operation of the water control structure on the lake has altered its hydrological regime to be more regular among years. Historic stage analysis revealed current lake levels are lower in the high-water spring, less variable in the dry period, and lack the extreme high-water events of 100+ years ago, all of which facilitate the expansion of woody vegetation.

Louisiana↗

USGS2019

Hydrologic modifications challenge bottomland hardwood forest management

Bottomland hardwoods are floodplain forests along rivers and streams throughout the southeastern United States. The interrelations among hydrology, soils, geomorphic landforms, and tree species composition are the foundation of forest management in bottomland hardwoods, and historically their correspondence has allowed for somewhat predictable forest responses based upon the hydrogeomorphic setting. However, extensive hydrologic and geomorphic modifications in floodplains have disrupted these interrelations and, on many sites, have created novel disturbance regimes resulting in unpredictable forest responses. Reduced or altered timing of surface flooding and groundwater declines are common in the region and have favored increases in stem densities, particularly of species less tolerant of flooding and more tolerant of shade. In these highly modified systems, more process-level understanding of floodplain hydrology, soil moisture dynamics, interspecific tree competition, and regeneration is needed to develop more effective management prescriptions and for forestry to be represented in integrated water-resource management decisions.

Journal of Forestry↗

USGS2006

Towards sustainable management of Louisiana's coastal wetland forests: Problems, constraints, and a new beginning

Over 345,000 ha of forested swamps occur throughout the Mississippi River Deltaic Plain. Natural and anthropogenic changes in hydrology and geomorphology at local and landscape levels have reduced the productivity in many of these coastal wetland forests areas and have caused the complete loss of forest cover in some places. A summary and interpretation of the available science, suggestions for policy change, and a multidisciplinary (multi-responsibility) approach were needed to address these issues [in the context of private land]. In response, the Louisiana Governor's office formed a Coastal Wetland Forest Conservation and Use Science Working Group (SWG) and an associated Advisory Panel to provide the Governor with information and suggestions of strategies for environmental and economic utilization, conservation, and protection of Louisiana's coastal wetland forest ecosystem in the long-term. The process of engaging scientists, resource managers, and other stakeholders in this effort is described, and the recommendations of the SWG are presented relative to forestry practices and the potential for sustainable management of coastal wetland forests.

Louisiana↗

USGS2004

An annotated bibliography of selected guides for stream habitat improvement in the Pacific Northwest

This annotated bibliography is a response to widespread interest in stream habitat improvement in the Pacific Northwest by land managers, governmental and nongovernmental organizations, and the lay public. Several guides to stream habitat improvement have been written in the past, but may not be easily accessible to people from diverse backgrounds. This annotated bibliography reviews 11 guides to stream habitat improvement so that readers can find literature appropriate to their needs. All reviews begin with summaries of the contents, stated audiences, and goals of each guide. Reviews also include subjective comments on the strengths and weaknesses of each guide. Finally, this bibliography includes recommendations of guides and combinations of guides judged most useful for a range of purposes.

Book↗