Dr. Paige Schmidt was recently invited by Louisiana State University’s School of Natural Resources to provide a seminar. Her presentation, “The role of science in the National Wildlife Refuge System: examples from Oklahoma and Texas” was well received. The examples she discussed included snowy plover monitoring at Salt Plains National Wildlife Refuge (NWR); evaluation of environmental DNA to determine the distribution and abundance of aquatic karst species at Ozark Plateau NWR and the Ozark Highlands Emphasis Area; standardized surveys of white-tailed deer at 3 refuges; the development of a duck-energy-model to determine how management decisions influence energetic carrying capacity for wintering waterfowl at Sequoyah NWR; and evaluation of forest and landbird monitoring data at Little River NWR. In addition to her presentation, Paige met with undergraduate and graduate students to discuss internship and career opportunities in the U.S. Fish and Wildlife Service. Many faculty were particularly interested to know what skills she felt were most important for recent undergraduates so they could ensure students leaving their program would be well-trained for today’s natural resources issues.
Previously, Paige attended the 23rd Annual Wildlife Society Conference, in Raleigh, North Carolina. Paige is an active member, former Chair, and current Secretary/Treasurer of TWS’ Native Peoples’ Wildlife Management Working Group which is composed of wildlife professionals and students, tribal and non-tribal, who recognize native people’s cultural, spiritual, and ecological connections to the land. TWS and the Working Group have been exploring ways to promote the development of indigenous wildlife students; both believe one of the most-effective ways to support indigenous wildlife students is to give them an opportunity to attend and participate in TWS’s Annual Conference – the largest gathering of wildlife professionals in North America. TWS, with support from multiple federal agencies, implemented a competitive Native Student Professional Development Program. Individuals selected for this program receive grants to cover costs of conference attendance along with a one-year membership in TWS and the Native People’s Wildlife Management Working Group, subscription to The Wildlife Professional and The Wildlifer, discounts on TWS peer-reviewed publications, and access to the TWS website, blog, career center, mentoring program, and other online resources. During the conference, participants are mentored through the working group. Paige has served as a mentor to program participants for several years and considers this to be one of the most important aspects of her attendance at the annual conference.
The Texas Chapter of the Wildlife Society met in February 2016 and recognized Dr. Matthew Butler as lead author for the “Best Technical Publication“. Specifically, the publication is the I&M protocol for surveying whooping cranes at and around Aransas National Wildlife Refuge in Texas (get protocol). Co-authors include: Cinthia Eichhorn, the talented Data Manager and GIS expert for USFWS southwest, and Brad Strobel, now the head biologist at Necedah National Wildlife Refuge in Wisconsin.
Dr. Jena Moon, Texas Gulf Coast Zone Biologist, was voted in as the Vice President of the Texas Chapter of the Wildlife Society! Jena is an excellent selection for the Board, given her hard work, dedication to wildlife management, and effective collaboration with the public, private landowners, state and federal agencies, and non-profit organizations. In her role, Jena is anticipated to promote a positive public image for the U.S. Fish and Wildlife Service, the Texas Chapter of the Wildlife Society, and the wildlife profession.
As a child my mother told me I would never have a career that kept me playing in the mud…..well she was only partially right. The mud of Texas coastal marshes hold the secrets of times gone past. We are currently starting a study of sediment depositions and elevation levels to understand past and current perturbations from widespread weather events such as hurricanes and long-term trends of climate change.
The Gulf Coast has suffered extensive loss of coastal marshes since human settlement. Where marsh loss has not been directly caused by rising sea level and other anthropogenic activities, it has been caused by a shift from emergent wetland vegetation to mudflats and open water due to salt water intrusion. Sea level rise, subsidence, and anthropogenic hydrological alterations have changed the environmental parameters that historically regulate coastal marsh function, resulting in their degradation. Global climate change additionally poses significant long-term threats to coastal marsh habitats and species that are dependent on those habitats along the Texas coast.
So how do we measure changes in marsh elevations? We measure elevation changes in coastal marsh with a Surface Elevation Table (SET for short).
SETs use a stable platform and a rotating horizontal arm to detect changes in elevation of the marsh surface. The arm is a portable mechanical leveling device for measuring relative sediment elevation changes. The arm has a series of pins that are dropped to the soil surface and then provide researchers with accurate and precise measurements (mm resolution) that are always taken in the exact location.
Over time these measurements can be mapped and then can provide trends of surface change over time.
This work is important because most climate change models are predicting appreciable sea-level rise along the Texas Gulf Coast. NOAA National Water Level Observation Network tide stations indicate that sea-level rise is not occurring at congruent levels along the entirety of the Texas Coast. Sea-level rise estimates from the Port Isabel tide station indicate a sea-level rise of 1.97 mm, well under the global average of 3.1 mm per year. However, tide stations near Galveston, Texas estimate sea-level rise to be occurring at 6.84 mm per year, over twice the global average. Because the rate of sea level rise for the upper Texas Coast is greater than the global average, it likely reflects the additional impact of local land subsidence due to oil and gas activities or ground water extraction. This information will allow the I&M program to improve climate modeling efforts on National Wildlife Refuges to improve species specific management such as those for whooping cranes and mottled ducks. Additionally, it will allow biologists and managers to better plan and carry out future conservation efforts.
In addition to SETs, coastal I&M staff have assisted in the collection of soil cores for vertical profiling of Cesium-137. Cesium occurs in distinct layers due to fall-out from nuclear testing in the 1940s-early 1960’s. In 1963 the Test Ban Treaty outlawed nuclear testing, which now is allowing geologists to use this unique signature within the soil profile to map long-term soil changes, aggradation and subsidence rates in coastal marshes.
We have collected several samples from Chenier National Wildlife Refuges Complex, Texas Mid-Coast Refuges Complex, and Aransas National Wildlife Refuge for analysis. This project aims to further our understanding of the impacts of sea-level rise, altered hydrology, and subsidence on coastal marshes by establishing a series of SET benchmarks and vegetation monitoring sites on coastal National Wildlife Refuges. The collected data will be compared to local rates of sea-level rise as observed through the National Water Level Observation Network tide stations. he data collected for this project should be able to measure minimum detectable changes in aggradation and subsidence that are significantly less than this observed rate of sea-level rise, and will provide valuable site level information regarding the effects of these processes in a variety of marsh types as well as insight to potential impacts on their future condition. Information collected will be used to improve conservation planning and management actions (e.g., restorative efforts, prescribed burning, etc.) within the coastal zone and to improve climate models (e.g., Sea-level Affecting Marshes Model).
Light Detection and Ranging airborne remote sensing technology, widely known as “LiDAR,” is being used more frequently as data collection and computing power for processing it become more affordable. It is often used to create a very detailed model of elevation and topography that can be used in a geographic information system (GIS). A LiDAR instrument sends thousands of infrared laser light pulses toward the ground from an airplane or helicopter and then simply records the x, y and z coordinates marking the return location for each beam of light. When viewed with specialized computer software, the points resemble a cloud, known as a “point cloud” that describes the height of objects. Detailed LiDAR “Bare Earth” models of topography are commonly at a much greater spatial resolution and vertical and horizontal accuracy than those developed through traditional methods such as aerial photography, making them well suited for civil engineering, geology, and hydrology applications.
Early on, LiDAR points returned from trees, buildings, and other objects above the ground were considered a nuisance to be removed before producing good topographic data. Nevertheless, scientists and natural resource managers quickly understood the value of LiDAR point clouds and potential to create highly detailed information about vegetation structure, habitat conditions, human infrastructure, geomorphology, and other land features that can vary substantially across large landscapes. This potential is now gaining the attention of many private, county, state, and federal entities who are finding LiDAR to be an essential tool for managing natural resources, urban growth, flood control, water management, disaster mitigation, and other purposes, naturally driving down the cost of acquiring LiDAR data.
Gaining ground for songbird conservation
Currently, LiDAR is opening new doors for characterizing and managing wildlife habitat for the US Fish and Wildlife Service (USFWS) Southwest Region Inventory and Monitoring (I&M) Program, starting with endangered songbirds. A common theme contributing to songbird declines is loss and fragmentation of habitat caused by agricultural development and urbanization. The Golden-cheeked Warbler (Setophaga chrysoparia) and Black-capped Vireo (Vireo atricapilla) were listed by the USFWS as Endangered in 1990 and 1987, respectively. The 25,000 acre Balcones Canyonlands National WildlifeRefuge (BCNWR) was established in 1992 to protect habitat for these two species. Both birds are Neotropical migrants, spending winter months in Mexico and Central America while occupying a narrow breeding range in the southwestern USA during the spring and summer. The warbler prefers older oak (Quercus spp.) and Ashe juniper (Juniperous ashei) woodlands while the vireo prefers semi-open shrublands.
BCNWR managers and I&M needed a way to determine where the most suitable habitat conditions exist for warblers and vireos on and off Refuge lands. Specifically, we wanted to know how future land acquisitions, habitat restoration, and protection activities can best be prioritized to make the most of resources allocated to warbler and vireo conservation.
Translating point clouds to habitat
In 2012, the first BCNWR-wide bird point count survey was conducted following a protocol developed by I&M Zone Biologist Dr. Jim Mueller. Drawing on modern sampling techniques from published studies, a total of 250 randomly selected locations were surveyed to record presence, distance, and time of detection of the Golden-cheeked Warbler and the Black-capped Vireo, and potential nest predators such as the Brown-headed Cowbird (Molothrus ater), Western Scrub-jay (Aphelocoma californica), and Blue Jay (Cyanocitta cristata), at four separate occasions during the breeding season. Detections for the Northern Bobwhite (Colinus virginianus), a species of conservation concern, were also recorded.
LiDAR and on-the-ground bird surveys are now beginning to play a role in estimating woodland conditions that are most important to the warbler and vireo, and eventually map locations across the landscape where they are likely to exist or which habitats are likely to be colonized in the future. Of considerable advantage, the state of Texas maintains substantial LiDAR data archives for many of the counties known to maintain warbler and vireo populations. In addition, the US Department of Agriculture National Agricultural Imagery Program (NAIP) acquires high-quality and high spatial-resolution color-infrared (CIR) aerial photography for the entire state of Texas every 2 to 3 years. Each of these data sources is freely available through the Texas Natural Resource Information System (TNRIS) and important to developing relationships between songbirds and habitat characteristics such as woodland vegetation composition and structure.
Remotely sensed data must first be processed, often using sophisticated computational techniques that require fast computers to translate them into information that is useful for conservation planning and management. However, results can be astonishingly accurate and simple to interpret for making management decisions. For the warbler, we have developed highly accurate vegetation height, density, and canopy cover data layers from LiDAR that can be mapped and quickly be related to preferred habitat conditions by songbirds.
Synthesizing LiDAR outputs with data collected in the field is not only telling a story about preferred songbird habitat conditions, but also where these conditions exist over large areas. A recent study by Farrell et al. (2013) provides an excellent example of how LiDAR derived vegetation data can be used effectively to identify key habitat for the Golden-cheeked Warbler and Black-capped Vireo on the Fort Hood military installation. We are taking similar steps to develop spatial models of songbird and nest-predator occupancy that will afford important information on where to prioritize conservation and habitat restoration actions both on and off Refuge lands. LiDAR and CIR imagery are also helping to address other questions such as understanding how understory vegetation, heterogeneity in height and canopy structure, successional status, and woodland species composition are related to the presence of warblers and vireos. This information will provide keen insights into how management activities such as hazardous fuels mitigation and other woodland treatments may best enhance habitat conditions and help minimize the negative influence of songbird nest predation. These monitoring and modeling activities are aimed at achieving refuge management goals, consistent with the 2001 Comprehensive Conservation Plan (2001) and Draft Habitat Management Plan (2010).
In the future, larger-scale efforts to characterize habitat conditions throughout the range of these two species may also help to identify locations where conservation credits to private land owners can best meet endangered songbird recovery objectives. Thus, the answer to these and many other questions about wildlife habitat relationships and management might just be in the clouds.
Balcones Canyonlands National Wildlife Refuge Comprehensive Conservation Plan. 2001. U.S. Fish and Wildlife Service, Albuquerque, New Mexico.
Balcones Canyonlands National Wildlife Refuge Habitat Management Plan (Draft). 2010. U.S. Fish and Wildlife Service, Marble Falls, Texas.
Farrell, S. L., B. A. Collier, K. L. Skow, A. M. Long, A. J. Campomizzi, M. L. Morrison, K. B. Hays, and R. N. Wilkins. 2013. Using LiDAR-derived vegetation metrics for high-resolution, species distribution models for conservation planning. Ecosphere 4:1-18.
Bitter Lake National Wildlife Refuge is home to 8 species that are listed as Federally Threatened or Endangered, and to several additional species listed as Threatened or Endangered by the State of New Mexico. Among the Federally Endangered species is a tiny snail, so small it went unnoticed until 1987. Pecos assiminea (Assiminea pecos) ranges in size from 1.4 to 2.2 mm. It occurs near the wetted edges (mud-water interface) of certain sinkholes, springs, and spring-runs (also known as cienega) on the Refuge. Pecos assiminea was listed as Endangered in 2005. In addition to Bitter Lake NWR, the snail is found on The Nature Conservancy’s Diamond Y Springs in west Texas.
Sketch of Pecos assiminea, excerpted from Taylor, 1987 (Figure 2):
Due in large part to its tiny size, it is extremely difficult to survey. Imagine trying to find a small brownish snail that is often less than 2 mm long in a shaded, uneven brown background; this difficulty is compounded because the habitat being searched is also full of small brown seeds, bits and pieces of small brown vegetation, and little mud stained salt crystals. Search efforts, thus, have traditionally been hindered because they were extremely time-consuming and tedious. Researchers have to lie on the ground with their face only a few inches above the ground, and several hours might be required to cover only a small area. Additionally, large-scale sampling efforts have been hindered by the lack of a feasible monitoring technique.
In 2011, Bitter Lake National Wildlife Refuge decided to pursue a monitoring effort that would help it better understand the species distribution, habitat associations, and density on the refuge. Field work for this project was largely carried out by Elizabeth (Beth) Roesler, who joined Bitter Lake NWR as an intern working for the Student Conservation Association. Roesler’s field work involved systematically searching areas of the Refuge where Pecos assiminea is known and suspected to occur. Roesler searched small quadrats of known size, and the quadrats were regularly spaced in searched habitats. She also collected habitat information concurrent with each quadrat searched, such as vegetation type, soil texture/saturation, ground temperature, and water quality (from adjacent spring flows). This information was collected in order to better understand habitat parameters associated with the species, and will eventually be incorporated into models that help predict where the species might occur. However, even with a scientifically rigorous sampling design, positive finds of Pecos assiminea were few and searches still proved to be a tedious process.
In fall of 2012, Roesler incorporated a second technique into her sampling efforts. This technique involved using known dimension wood tiles, and was suggested by Brian Lang, invertebrate biologist with New Mexico Department of Game and Fish. Known dimension clay tiles are often used to sample aquatic snails, but Lang’s prior experience using clay tiles in attempts to sample Pecos assiminea had proved unsuccessful. However, since Pecos assiminea are sometimes seen attached to small wood fragments, wood tiles seemed like they warranted a try.
Initially, wood tiles were placed on the ground only along the edges of Sinkhole 31, which is believed to have the highest densities of Pecos assiminea on the Refuge. Roesler’s use of wood tiles proved almost immediately successful. Within a few weeks, Pecos assiminea began to attach to the wood tiles, and detection rates with tiles were much higher than detection rates from visually searching quadrats of known area.
As opportunity would have it…
In 2012, Bitter Lake NWR received an “Invasives with Volunteers” grant, which enabled them to initiate an ambitious phragmites (pronounced frag-mit-ies) plant removal program to restore a 1 mile spring run (approximately 7 acres of cienega habitat), known as Bitter Creek, to conditions that existed prior to phragmites invasion. One of the goals of removing phragmites was to alter habitat in favor of Pecos assiminea and the 5 other federally listed species that occur there. Pecos assiminea snails rarely occur in phragmites dominated habitats and declined along Bitter Creek after the spread of this invasive plant species.
Subsequent to receiving the “Invasives with Volunteers” grant, Texas Tech University received a Science Support Grant in partnership with U.S. Geological Survey and the Refuge. The purpose of this grant was to monitor the response of Pecos assiminea to phragmites removal on Bitter Creek. As Roesler was already experimenting with two monitoring techniques (visual searches of small quadrats and wood tiles) to monitor this species, and had already fully sampled Bitter Creek the prior year using quadrat searches, she was the best choice to make the leap from Student Conservation Association intern to graduate student. In spring of 2013 she enrolled as a graduate student at Texas Tech University to work on the Science Support Grant funded project. Two main goals of her graduate project are to monitor the effects of phragmites removal on Pecos assiminea, and to concurrently examine the efficacy of the two monitoring techniques mentioned above. Unlike most graduate students in the field of conservation science, Roesler actually entered graduate school as one of the leading experts on her study species. Thanks to her Student Conservation Association internship, perhaps only 1 or 2 people in the world have observed and sampled more Pecos assiminea than Roesler.
So what does Bitter Lake NWR gain from this project? First, the Refuge aims to benefit an endangered species through its management actions/prescriptions, and the monitoring effort will help the Refuge learn how the species responds. Secondly, the Refuge will get answers concerning the efficacy of two potentially suitable sampling techniques that can each be used to answer questions about Pecos assiminea distribution and density. Hopefully one of the techniques can be used for “operational” monitoring for the species. From a general conservation standpoint, the U.S. Fish and Wildlife Service will get estimates of Pecos assiminea density in multiple habitats, which will be among the first abundance estimates for this species! Upon completion of the work, the Refuge will have enough information to make reasonable predictions about the response of Pecos assiminea to phragmites control if additional removal efforts are pursued, and, lastly, the Refuge should have enough information to start modeling likely occurrence of Pecos assiminea based on its habitat parameters. This project is adaptive management at its best.
Citation: Taylor, D.W. 1987. Fresh-water mullusks from New Mexico and vicinity. New Mexico Bureau of Mines and Mineral Resources Bulletin 116.