Geology topics

Research about Cache River

Source-linked reports with geographic coverage including Cache River.

4 recordsLinked to original sources

USGS2003

Soil seed banks and the potential restoration of forested wetlands after farming

1 Changes in farming practice provide an opportunity to restore once extensive forested wetlands on agricultural land. In some parts of the world, however, it has proved difficult to restore the full complement of plant species through natural regeneration. Similarly, the restoration of forested wetlands by replanting has often resulted in ecosystems of low diversity. Better methods of restoring these important ecosystems are now required and baldcypress swamps provide an opportunity to investigate alternative approaches to the restoration of forested wetlands. This study examined the composition of seed banks of farmed fields to determine their value in restoring swamps in the south-eastern United States. 2 A seed bank assay of soils from baldcypress swamps was conducted to determine the extent to which seeds are maintained during farming for various lengths of time. Soils from swamps that were farmed for 0–50 years were collected near the northern boundary of the Mississippi Alluvial Valley along the Cache River, Illinois. Soils were placed in a glasshouse setting in flooded and freely drained conditions, and the numbers and species of seeds germinating were recorded. 3 Woody species including trees, shrubs, and vines were poorly represented in seed banks of both farmed and intact sites (51 and 9 sites, respectively). Missing dominants in the seed banks included tree species with short-lived seeds such as Taxodium distichum and Nyssa aquatica . Cephalanthus occidentalis constituted the most abundantly dispersed seed of all woody species. 4 Herbaceous species were well represented in the seed banks of both farmed and intact swamps (species richness of 207 vs. 173 species, respectively) suggesting that herbaceous species may live longer than woody species in seed banks. Few of the herbaceous species decreased in seed density in seed banks with time under cultivation, although seed density was lower at sites that had not been farmed. Species that relied on vegetative organs for dispersal were absent in the seed banks of farmed sites including Heteranthera dubia , Hottonia inflata , Lemna minor , Lemna trisulca and Wolffia columbiana . These species may require active reintroduction during restoration. 5 Synthesis and applications. Both restoration ecologists and managers of nature conservation areas need to be cognisant of seed bank and dispersal characteristics of species to effectively restore and manage forested wetlands. In the case of baldcypress swamps, critical components of the vegetation are not maintained in seed banks, which may make these floodplain wetlands difficult to restore via natural recolonization. Ultimately, the successful restoration of abandoned farm fields to forested wetlands may depend on the re-engineering of flood pulsing across landscapes to reconnect dispersal pathways.

Illinois↗

USGS2002

Effects of canopy gaps and flooding on homopterans in a bottomland hardwood forest

Canopy disturbance is a major factor affecting forest structure and composition and, as a result of habitat alterations, can influence insect communities. We initiated a field study to quantify the effects of canopy disturbance on aerial insect abundance and distribution within a bottomland hardwood forest along the Cache River, Arkansas, USA. We used passive flight-intercept traps to sample insects in canopy gap and forest interior habitats from May to July in 1996, 1997, and 1998. The hydrologic conditions of our study site varied among years: 1996 was relatively dry, 1997 incurred a long-duration flood, and 1998 was moderately wet. Of the 34,000+ Homopterans collected, many groups were distributed in a non-uniform manner among years and between habitats. Total Homopterans, two families of Homopterans, and six morphospecies were more abundant in canopy gaps than interior forest. Many Homopteran taxa were least abundant in 1997 following almost six months of flooding. Alternatively, relatively large Homopteran abundances were associated with the dry conditions of 1996 and the moderately wet conditions of 1998. Differences in Homopteran abundance among years and habitats may be related to differences in vegetation density. Canopy gaps supported more vegetation cover than the interior forest in all but the first sampling interval. In addition, similar to Homopteran abundance, vegetation density was lower in 1997 than in 1998. These results demonstrate that natural disturbance and flooding contribute to Homopteran abundance and distribution patterns in bottomland hardwood forests of the south central United States.

Arkansas↗

USGS1996

Denitrification in bottomland hardwood wetland soils of the Cache River

Denitrification rates were quantified in bottomland hardwood wetland soils of the Cache River. N 15 labeled nitrate was added to columns containing wetland soils and river water. Over 40 days, nitrate-N in floodwater (approximately 9 mg N L −1 ) decreased by between 82% and 59%, which gave estimates of N export from the water column of between 11.5 mg N m −2 day −1 and 7.5 mg N m −2 day −1 . These values correlated directly with organic content of surface sediment, which included forest litter. Added glucose doubled rates of nitrate loss in these soils, which indicated that the process was carbon limited. Nitrification occurring simultaneously with denitrification was determined using isotopic dilution techniques. Contributions of nitrate to water from nitrification were estimated at between 5% and 12% of the total nitrate reduced. Rates of nitrogen transformation in these forest soils were likely limited by available soil carbon from tree litter and perhaps canopy leachate, rather than by nitrate concentration in inflowing floodwater.

Wetlands↗

USGS1977

Well records, water-level measurements, logs of test holes, and chemical analyses of ground water in the Cache River alluvial aquifer-stream system, northeast Arkansas, 1946-76

Most of the ground-water data for the Cache River alluvial aquifer-stream system in northeast Arkansas were collected between March 1973 and April 1976, but some were collected as early as April 1946. The data includes records of 363 wells and test holes, water-level measurements of 295 wells, logs of 32 test holes, and chemical analyses of water samples from 85 wells.

Arkansas↗