Geology topics

Research about Lafayette, Louisiana

Source-linked reports with geographic coverage including Lafayette, Louisiana.

3 recordsLinked to original sources

USGS2023

Thirteen years of turtle capture–mark–recapture in a small urban pond complex in Louisiana, USA

Turtles are one of the most imperiled vertebrate groups in the world. With habitat destruction unabated in many places, urban and suburban greenspaces may serve as refugia for turtles, at least those species able to tolerate heavily altered landscapes. In south-central Louisiana, we have conducted a turtle capture–mark–recapture effort in two ponds in an urban greenspace for 13 yr to understand species composition, survival, and individual growth rates. We had 574 total captures of 251 individuals of five species from 2009–2021, with Trachemys scripta elegans (Red-Eared Sliders) and Sternotherus odoratus (Eastern Musk Turtles) being the most common. Apparent annual survival for T. scripta (0.79) was similar to estimates reported in other studies in altered habitats, whereas apparent annual survival for S. odoratus (0.89) was slightly or much higher than other published studies. Growth rates of T. scripta were comparable to other studies and showed both sexes have similar rates of growth until maturity, which is earlier and at a smaller size in males. The two ponds showed marked differences in captures by size, with significantly more juvenile T. scripta captured in the pond with more vegetation, depth, and a softer bottom. Most T. scripta (78.5%) that were recaptured came from the same pond from which they were originally captured. The basic demographic data gained in this study can serve as a starting point for broader questions on urbanization effects and as a comparison to more natural populations.

Louisiana↗

USGS2013

Dendrometer bands made easy: using modified cable ties to measure incremental growth of trees

Dendrometer bands are a useful way to make sequential repeated measurements of tree growth, but traditional dendrometer bands can be expensive, time consuming, and difficult to construct in the field. An alternative to the traditional method of band construction is to adapt commercially available materials. This paper describes how to construct and install dendrometer bands using smooth-edged, stainless steel, cable tie banding and attachable rollerball heads. As a performance comparison, both traditional and cable tie dendrometer bands were installed on baldcypress trees at the National Wetlands Research Center in Lafayette, Louisiana, by both an experienced and a novice worker. Band installation times were recorded, and growth of the trees as estimated by the two band types was measured after approximately one year, demonstrating equivalence of the two methods. This efficient approach to dendrometer band construction can help advance the knowledge of long-term tree growth in ecological studies.

Louisiana↗

USGS2008

Where temperate meets tropical: Multi-factorial effects of elevated CO2, nitrogen enrichment, and competition on a mangrove-salt marsh community

Our understanding of how elevated CO 2 and interactions with other factors will affect coastal plant communities is limited. Such information is particularly needed for transitional communities where major vegetation types converge. Tropical mangroves ( Avicennia germinans ) intergrade with temperate salt marshes ( Spartina alterniflora ) in the northern Gulf of Mexico, and this transitional community represents an important experimental system to test hypotheses about global change impacts on critical ecosystems. We examined the responses of A. germinans (C 3 ) and S. alterniflora (C 4 ), grown in monoculture and mixture in mesocosms for 18 months, to interactive effects of atmospheric CO 2 and pore water nitrogen (N) concentrations typical of these marshes. A. germinans , grown without competition from S. alterniflora , increased final biomass (35%) under elevated CO 2 treatment and higher N availability. Growth of A. germinans was severely curtailed, however, when grown in mixture with S. alterniflora , and enrichment with CO 2 and N could not reverse this growth suppression. A field experiment using mangrove seedlings produced by CO 2 ‐ and N‐enriched trees confirmed that competition from S. alterniflora suppressed growth under natural conditions and further showed that herbivory greatly reduced survival of all seedlings. Thus, mangroves will not supplant marsh vegetation due to elevated CO 2 alone, but instead will require changes in climate, environmental stress, or disturbance to alter the competitive balance between these species. However, where competition and herbivory are low, elevated CO 2 may accelerate mangrove transition from the seedling to sapling stage and also increase above‐ and belowground production of existing mangrove stands, particularly in combination with higher soil N.

Louisiana↗