Monday, January 30, 2012

Field technicians with the NEON network

There are several field technician positions (at many experience levels) currently available with the NEON network. See the "We're Hiring" section on their webpage for position descriptions and locations.

Friday, January 20, 2012

Summer research internships for undergraduates at TAMUG

TAMUG has several summer internships available through the NSF Research Experience for Undergraduates program. My Coastal and Wetlands Ecology lab is one of several potential labs that can host interns. The application deadline is Feb 15, and information can be found here:

Wednesday, January 18, 2012

Wetland biologist opening with AECOM

The Environmental Consulting Agency AECOM (Houston office) is looking for an entry level wetland, permits, and NEPA biologist. Preferred qualifications include some training and experience in the field. If you are interested, please send your resume to Timothy Love at

Tuesday, January 17, 2012

More of the latest from the Wetlands Lab

Following is the abstract of a manuscript currently in press at the Journal of Coastal Research.

The response of photosystem II to soil salinity and nutrients in wetland plant species of the northwestern Gulf of Mexico
Eric N. Madrid, Anna R. Armitage, and Antonietta Quigg

The photosynthetic response of many wetland plant species to soil salinity and nutrients has been described in the laboratory, but less is known about the cumulative effect of these abiotic factors in the natural environment. In this investigation we correlated field measurements of chlorophyll fluorescence with simultaneous measurements of soil nitrogen and phosphorus content, soil salinity, and relative leaf nitrogen content in four species (Spartina alterniflora Loisel, S. patens (Aiton) Muhl, Schoenoplectus californicus (C.A. Mey.) Steud. and S. robustus (Pursh) M.T. Strong), that are common in brackish and salt marshes of the northwestern Gulf of Mexico. We found that the range of environmental conditions experienced by each species in the field is greater than what has been considered in laboratory investigations, and that saline soils may elicit an inverse photochemical response that has not been documented in the laboratory. The relationship between chlorophyll fluorescence and soil N:P ratio was not significant in S. alterniflora, nonlinear in S. patens and S. robustus, and significant and positive in S. californicus. The relationship between leaf nitrogen content and effective quantum yield was significant and positive in S. alterniflora and S. robustus, but only S. alterniflora appeared to be able to increase relative leaf nitrogen content over a wide range of soil nutrient and salinity regimes. S. californicus had the greatest potential for photosynthetic light capture but also had the narrowest ecological distribution. Thus, the species best adapted to high levels of abiotic stress (S. alterniflora) was less dominant at lower salinities, and species with the highest potential for photosynthetic performance (S. robustus and S. californicus) were only found in locations with favorable abiotic conditions.

The research in this article was supported by grants from the Texas General Land Office, Oil Spill and Response Division, and from the GLO Coastal Management Program.

Latest findings

Below are recent abstracts from our research lab. These talks were presented at the Coastal and Estuarine Research Federation 2011 meeting.

Metapopulation dynamics in estuarine habitat restoration: Do reference areas act as source populations?
Anna R. Armitage, Michael T. Bell, Chuan-Kai Ho, Eric N. Madrid, Antonietta S. Quigg
Consideration of metapopulation dynamics in habitat restoration can help to identify suitable source populations to supply restored areas. Metapopulation theory stipulates that source populations will have positive intrinsic growth rates; therefore, we predicted that aquatic faunal populations in reference (source) areas would have higher intrinsic growth rates than in restored (sink) areas. Second, a metapopulation exists if patches of habitat are connected and are suitable for colonization; therefore we predicted that organisms would disperse to and colonize restored areas where the habitat was suitable. To test these hypotheses, we monitored habitat characteristics and densities of three common aquatic species (sailfin molly Poecilia latipinna; rainwater killifish Lucania parva; grass shrimp Palaemonetes pugio) in three patches of recently restored brackish marsh and one reference area in the northwestern Gulf of Mexico from 2008 to 2010. All habitat patches were connected by a network of permanently inundated channels. Faunal densities were constant over time in the reference area but increased in most of the restored areas. This suggests either that (a) the reference area served as a source population that supplied the restored areas with recruits, or (b) the intrinsic growth rate was higher in restored than in reference areas. We used principal components analysis to define threshold suitability values for key habitat characteristics. Only Poecilia density was significantly related to habitat characteristics in the reference site, but Poecilia densities were not higher in restored areas with ideal habitat features than in unsuitable restored areas. Therefore, habitat suitability did not appear to be the primary driver influencing faunal colonization of restored habitat. Our results suggest that metapopulation dynamics were not strongly influencing restored site colonization at this spatial scale. 

Does ecotypic-based genetic diversity of a dominant plant impact ecosystem health and stability? A case study in a restored Spartina alterniflora marsh
Courtney T. Lee and Anna R. Armitage
Increased genetic diversity of habitat-forming species correlates with increased faunal diversity and enhances ecosystem resiliency to and recovery from disturbances. Genetic diversity at the species level may be just as important as species diversity for the long term health and stability of ecosystems. To identify the benefits of increased genetic diversity within a single plant species, I performed a common garden experiment in a constructed salt marsh in Galveston Bay, Texas. The nutrient acquisition patterns and productivity of genetically distinct Spartina alterniflora populations (ecotypes) in monoculture plots (single population) were compared to polyculture plots (two or three populations). Early trends suggest that polyculture treatments have more live plant material and increased shoot production a month after transplanting. I also examined interactions between increased genetic diversity of S. alterniflora and its colonizing insect and spider communities. At this early development stage of the restored marsh, few of these arthropods have colonized the study plots, but faunal response to plant genetic diversity may strengthen over time as the plant community develops. In an effort to maintain diverse community assemblages and ecosystem stability, increased genetic diversity of a dominant primary producer may be an important consideration. 

These projects were supported by grants from the Texas General Land Office Oil Spill Response Division and the GLO Coastal Management Program