Contract Research Findings: Habitat
| Title: | Groundwater supply in Texas: private land considerations in a rule-of-capture state |
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| Journal/Year: | Society and Natural Resources/2004 |
| View: | Visit Taylor & Francis Online - Groundwater supply in Texas: private land considerations in a rule-of-capture state |
| Author(s): | Matthew W. Wagner|Urs P. Kreuter |
| Keywords: | cooperative management|groundwater districts|groundwater markets|local control|rule-of-capture|water supply|wildlife cooperatives |
| Abstract: | Texas is a top water-consuming state in the United States and is increasingly relying on groundwater. Groundwater markets are attracting greater attention as a mechanism for transferring water from rural to urban areas. However, excessive extraction is being exacerbated by the "rule-of-capture" that governs the use of groundwater in Texas combined with widespread subdivision of land. Overexploitation of common-pool resources is not inevitable. A cooperative approach to groundwater management could reduce the negative economic impacts of water transfers in the area of origin and provide landowner incentives to regulate extraction. Landowner associations, monitored by local groundwater conservation districts, offer an instructive model for sustainably managing groundwater while at the same reallocating water resources from rural to municipal uses. |
| Management Implications: | For nearly 100 years, the "rule-of-capture" has survived attempts to regulate groundwater use in Texas. Under this rule, the combination of the need for efficient water supply to urban areas and accelerating rural land subdivision creates challenges that beg for a unified approach to land and water conservation. Coordinated marketing of groundwater by rural landowners could provide an important economic incentive to maintain open space that benefits aquifer recharge as well as wildlife habitat. By coordinating the shared interest of landowners to benefit from groundwater, locally controlled associations could facilitate the distribution of groundwater to locations of greatest need. Because groundwater districts are already authorized to prevent overuse of aquifers and can be operated by landowner representatives, they are the logical institutional entity for coordinating groundwater extraction plans developed by landowner associations, for monitoring extraction rates, and for implementing sanctions against non-compliant landowners. Under this scenario, government oversight and enforcement would be limited to ensuring that groundwater districts adhere to safe use levels for the aquifer. Potential case studies of groundwater marketing associations, such as the Middle Trinity Basin Conservation Cooperative, are arising but they are in their infancy. A detailed study of a wider spectrum of landowner associations in Texas is needed to understand the advantages and limitations of such associations for ensuring the sustainable supply of groundwater and for developing water markets through transfers of groundwater from rural to urban areas. Such a study would also provide important lessons for the cooperative management of other commonpool resources both in Texas and elsewhere. |
| Citation: | Wagner, M. W., and U. P. Kreuter. 2004. Groundwater supply in Texas: private land considerations in a rule-of-capture state. Society and Natural Resources 17:349-357. |
| Title: | Integrating land conservation planning in the classroom |
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| Journal/Year: | Wildlife Society Bulletin/2005 |
| View: | Visit Wiley Online Library - Integrating land conservation planning in the classroom |
| Author(s): | Roel R. Lopez|K. Brian Hays|Matt W. Wagner|Shawn L. Locke|Robert A. McCleery|Nova J. Silvy |
| Keywords: | conservation planning|education|experiential learning|management plans|students|wildlife careers|wildlife education|writing |
| Abstract: | Opportunities for wildlife undergraduates to engage in land conservation planning can bridge the gap between formal academic training and professional wildlife experiences. Land conservation plans are an important component in managing wildlife habitat. In 1995 state legislation offered Texas landowners the opportunity to remain under agricultural valuation (Texas House Bill 1358, Proposition 11, 1-d-1) by designating wildlife management activities as qualifying agricultural practices. To obtain a wildlife management tax valuation, a landowner must have an active, written wildlife management plan. Texas Parks and Wildlife Department (TPWD) biologists often provide technical guidance to landowners in this process. Allowing wildlife undergraduates to have an active role in this process offers a unique opportunity for them to gain practical "hands-on" experiences while improving their writing skills. Students enrolled in Wildlife Habitat Management and Conservation (WFSC 406) work in groups (3-4 students) to develop a management plan for 3 local landowners. In addition to writing an actual management plan, students gain experience in land surveying, vegetation sampling, GIS/GPS technology, and public speaking. Landowners receive 3 peer-reviewed management plans they can select from to implement on their property. Students assist TPWD biologists and Texas Cooperative Extension staff in providing technical guidance to local landowners. Wildlife education can be enhanced by integrating land conservation planning in the classroom via partnerships with natural resource agencies and landowners. |
| Management Implications: | We found use of experiential learning and writing pedagogies in WFSC 406 to be effective in teaching wildlife undergraduates the basics in wildlife-habitat management and conservation planning. In addition to a strong background in basic ecological and wildlife-management principles, wildlife students also obtained problem-solving skills, team-work experience, and exposure to budget management and report writing. Students also gained experience in habitat assessment, GIS and GPS technology, and public speaking. Most importantly, wildlife students were able to synthesize and present information learned in the classroom in the form of a written wildlife management plan presented to landowners and professional wildlife biologists. One of the unique results from our classroom activity was the interaction of student teams with actual landowners as opposed to fictitious scenarios often presented in wildlife courses. Students gained an understanding of the challenges of working with landowners with diverse perspectives and opinions during the development of landowner plans. Student feedback has been positive in the use of a wildlife management plan in the classroom. For example, students responded the management plan was a useful exercise in class from recent class surveys (Fall 2004 and Spring 2005 class survey data, n = 50; 41/50, 82%, A = strongly agreed; 9/50, B = 18% agreed). Students also like the idea of working with local landowners (Fall 2004 and Spring 2005 class survey data, n = 50; 45/50, 90%, A=strongly agreed; 5/50, B=10% agreed) and TPWD biologists (Fall 2004 and Spring 2005 class survey data, n = 50; 45/50, 90%, A = strongly agreed; 4/50, B = 8% agreed; 1/50, 2%, C = undecided). For landowners, class participation resulted in 3 peer-reviewed management plans they could select to implement on their property. Landowner feedback throughout the semester allows management plans to be tailored to landowner objectives and needs. To date, all previous management plans have been used by landowners (10 landowners since 2003), though the number of actual recommendations implemented has varied (e.g., landowner implements 2 of 3 recommendations selecting to implement a different recommendation for his or her third option). Management plans were conducted free of charge. For TPWD biologists, WFSC 406 students assisted them in fulfilling their mission of providing technical guidance to local landowners. In our case the regional TPWD biologist was assisted in preparing 10 management plans for local landowners since 2003. We propose that wildlife education can be enhanced by integrating land-conservation planning in the classroom via partnerships with natural resource agencies and landowners. |
| Citation: | Lopez, R. R., K. B. Hays, M. W. Wagner, S. L. Locke, R. A. McCleery, and N. J. Silvy. 2005. Integrating land conservation planning in the classroom. Wildlife Society Bulletin 34:223-228. |
| Title: | Linking water conservation and natural resource stewardship in the Trinity River Basin |
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| Journal/Year: | Texas Cooperative Extension/2007 |
| View: | Download Cathey_etal_2007_TrinityRiver.pdf |
| Author(s): | James C. Cathey|Shawn L. Locke|Andrea M. Feldpausch|Israel D. Parker|Carl Frentress|Jay Whiteside|Corey Mason|Matthew W. Wagner |
| Abstract: | As the population of Texas continues to grow, water issues will become a central focus. Water supplies are not growing. Clearly, we must consider alternative ways and seek new innovations for conserving water to meet future demands. Conservation efforts are particularly important in the Trinity River Basin because the river supplies water to approximately 40% of the state's residents. Faced with water shortage and quality issues, Texans have a growing interest in gaining information regarding watershed and land management practices. This improved information is necessary to bridge the watershed and water-use knowledge gap. Within the Trinity River watershed today, municipalities use more water than agricultural and industrial-related activities. Over the last several decades, people have migrated from rural areas to predominately urban areas. Managing this change will require a shift in thinking as individuals and civic leaders redefine how they influence water conservation. Having knowledge of soil, water, flora, fauna and the management practices necessary to enhance ecosystem function will become more important for those engaged in water and land stewardship. Past and current winners of the LSLSA and work done by Texas Master Naturalist offer good examples of how to conduct conservation efforts on large and small landscape scales within the framework of their own land ethic. Good management maximizes both environmental health and output. However, bad management impairs the ability of the environment to provide essential services both now and in the future. To aid decision-making, we provide contacts and sources of more information needed by landowners and stakeholders to further educate themselves on water-related issues. Accurate information is vital for the specific and positive land management required to ensure the availability of quality water in a growing and changing Texas. As the 512-mile course of the Trinity River passes through 38 counties and several major ecoregions, it delivers ecosystem services that benefit nature and humans. Although our tendency is to remove ourselves from nature, it is obvious that we are intimately connected, and conservation efforts need to be employed now in order to provide water in the future. |
| Citation: | Cathey, J. C., S. L. Locke, A. M. Feldpausch, I. D. Parker, C. Frentress, J. Whiteside, C. Mason, and M. W. Wagner. 2007. Linking water conservation & natural resource stewardship in the Trinity River Basin. Texas Cooperative Extension Report, Texas A&M University, College Station, USA. |
| Title: | Managing the commons Texas style: wildlife management and ground-water associations on private lands |
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| Journal/Year: | Journal of the American Water Resources Association/2007 |
| View: | Download Wagner_etal_2007_Groundwater.pdf |
| Author(s): | Matthew Wagner|Ronald Kaiser|Urs Kreuter|Neal Wilkins |
| Keywords: | ground-water management|private lands|social capital|landowner associations|water policy|planning |
| Abstract: | As nearly all of Texas' rural lands are privately owned, landowner associations for the management of white-tailed deer and ground-water have become increasingly popular. Deer are a common-pool resource with transboundary characteristics, requiring landowner cooperation for effective management. Ground-water reserves are economically important to landowner, but are governed by the "rule of capture" whereby property rights are not defined. One ground-water association and four wildlife management associations (WMAs) were surveyed to characterize their member demographics, land use priorities, attitudes, and social capital. Members of the ground-water cooperative were part of a much larger, more heterogeneous, and more recently formed group than members of WMAs. They also placed greater importance on utilitarian aspects of their properties, as opposed to land stewardship for conservation as practiced by members of WMAs. If ground-water association members could be more locally organized with more frequent meetings, social capital and information sharing may be enhanced and lead to land stewardship practices for improved hydrologic functions and sustained ground-water supply. This, coupled with pumping rules assigned by the local ground-water district, could yield an effective strategy that is ecologically and hydrologically sound, and that allows rural provision of water supply to urban consumers. |
| Citation: | Wagner, M., R. Kaiser, U. Kreuter, and N. Wilkins. 2007. Managing the commons Texas style: wildlife management and ground-water associations on private lands. Journal of the American Water Resources Association 43:698-711. |
| Title: | Effects of grassland restoration on avian assemblage characteristics and dickcissel nesting success in Texas |
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| Journal/Year: | Thesis/2009 |
| View: | Download Lituma_2009_GrasslandRestoration.pdf |
| Author(s): | Christopher M. Lituma |
| Abstract: | The prairies of North America have undergone substantial changes since European settlement in the 1800's, with some estimates suggesting that 96% of the tallgrass prairie has been converted. Multiple factors contributed to reduction in prairie, including: grazing, row-crop farming, depressed fire regimes, and exotic grass species introduction. In Texas, 35% of the historic grassland ecosystems have been either altered or converted. Introduced in the 1940's, exotic grass species such as Bermuda grass (Cynodon sp) have displaced native grass species throughout Texas. Introduced grass species can alter the existing plant communities degrading habitat for birds and other animals. Grassland birds are declining faster than any other bird group within North America; due in part to a reduction in suitable breeding habitat. I addressed this issue by comparing nesting success of grassland birds between exotic grass sites and restored native grass sites in the blackland prairie region of east-central Texas during 2007-2008 breeding seasons. I conducted point counts and nest searching from March - July. Point count data indicate no difference in species richness between sites. Dickcissel (Spiza americana) nests represented 89% of the nests found (n = 104). Dickcissel abundance was 44% higher in restored sites and 76% of nests were located in restored sites. Daily survival (DSR) for dickcissels in restored sites was 0.895 (SE = 0.013) and for exotic sites was 0.930 (SE = 0.017). I used an independent samples t-test to compare mean nest height, which was 56% higher in restored sites than exotic sites (n = 83, = 38.0 cm ± 1.90; = 15.2 cm ± 2.19, df = 81, t = -6.31, P = 0.001), and mean nest substrate height which was 58% higher in restored sites than in exotic sites (n = 83, = 118.8 cm ± 6.50; = 46.5 cm ± 4.77, df = 81, t = -6.08, P = 0.001). Although dickcissel abundance was greater in restored sites than exotic sites, their observed nesting success and DSR was lower in restored sites. This is indicative of an ecological trap, which occurs when an organism is attracted to a habitat that negatively impacts the organism. Some research suggests that restored fields in other states are acting as traps for dickcissels, and according to my results restored sites I sampled may also be acting as ecological traps for dickcissels in Texas. |
| Management Implications: | Continued research in the blackland prairie region of Texas should focus on the predator community. Though I did not identify predators for this study because of logistical constraints, I noted signs of predation and the majority of predatory signs suggest that snakes are the main predator in this area. Snakes are a common predator of many passerines including dickcissels (Pietz and Granfors 2000, Renfrew and Ribic 2003, Stake et al. 2005). These restored areas are attracting large numbers of dickcissels, which are potentially attracting predators. Dickcissels were among the most abundant bird species detected on all sites, and this is likely another reason for high depredation. My research provides information suggesting more dickcissel nests fledged in restored areas than in exotic areas, despite a lower DSR and observed success. According to my research prairie restorations in Texas are positively impacting the dickcissel. Further research is needed to definitively state what the cause for high predation rates in this area is, and to more accurately assess the predator community (Vickery and Herkert 2001, Renfrew and Ribic 2003, Weatherhead and Blouin-Demers 2004, Fletcher et al. 2006). |
| Citation: | Lituma, C. M. 2009. Effects of grassland restoration on avian assemblage characteristics and dickcissel nesting success in Texas. Thesis, Texas A&M University, College Station, USA. |
| Title: | Effects of summer and winter burning on vegetation and wildlife in a sand sagebrush/honey mesquite savanna |
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| Journal/Year: | Thesis/2009 |
| View: | Download Poole_etal_2009_BurningVegetation.pdf |
| Author(s): | Matthew W. Poole |
| Abstract: | There is substantial information on the generalized effects of fire in some grassland ecosystems. However, studies addressing seasonality of fire are less common. The Rolling Plains have high climatic variability with periodic droughts; however, little information is available on the potential role of burning in these communities under these conditions. Therefore, I initiated a project to explore the effects of seasonality of fire on a sand prairie ecosystem. We established 5 blocks of 3 18-ha plots at Matador Wildlife Management Area (WMA) in Cottle County, Texas. Each plot, within a block, was randomly assigned to a summer burn (August), winter burn (February), or a control (no fire) treatment. Herbaceous vegetation cover and frequency were measured twice annually (May-June and August-September) using 0.1 m² quadrats, while woody cover was measured during late summer using the line-intercept method. Invertebrates, herpetofauna, and small mammals were sampled utilizing drift fence arrays during the spring and summer. Invertebrates were also sampled in late summer using sweep nets and small mammals were also sampled twice annually using Sherman live traps. Summer burning appeared to benefit forbs, species richness, evenness and diversity. In general, forbs were not affected by winter burning, but forbs were similar to grasses, in that individual species' responses to winter burning were variable. My results indicated that prescribed summer burning appears to be effective at reducing, but not eliminating sand sagebrush, honey mesquite, prickly pear, yucca, and total woody canopy cover. Summer burning was the most effective treatment at reducing honey mesquite and sand sagebrush, which may have promoted the observed increases in herbaceous vegetation by making resources, such as light and water, available to grasses and forbs. However, many of the wildlife species examined did not respond to the application of summer and winter burning, but responded to onset of drought conditions. Therefore, a combination of both summer and winter burning treatments are recommended for suppressing woody plant cover and increasing overall plant diversity by promoting desirable herbaceous species for a wide variety of wildlife and livestock. Longer term research on the effects of summer and winter burning on herbaceous and woody vegetation, especially in drought years, is needed to fully evaluate the effects of burning in the Rolling Plains of Texas. |
| Citation: | Poole, M. W. 2009. Effects of summer and winter burning on vegetation and wildlife in a sand sagebrush/honey mesquite savanna. Thesis, West Texas A&M University, Canyon, USA. |
| Title: | Grassland bird associations with introduced and native grass conservation reserve program fields in the southern High Plains |
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| Journal/Year: | Western North American Naturalist/2009 |
| View: | Visit BioOne - Grassland bird associations with introduced and native grass conservation reserve program fields in the southern High Plains |
| Author(s): | Thomas R. Thompson|Clint W. Boal|Duane Lucia |
| Keywords: | Ammodramus savannarum|Aimophila cassinii|Cassin's sparrow|conservation reserve program|Eremophila alpestris|Grasshopper sparrow|horned lark|Passerculus sandwichensis|Savannah sparrow|Sturnella neglecta|Western meadowlark |
| Abstract: | We examined relative abundances of grassland birds among Conservation Reserve Program (CRP) fields seeded with 2 monocultures of introduced grass species and 2 mixes of native grasses in the Southern High Plains of Texas. We assessed bird compositions among these 4 cover types and between the cover types pooled into categories of introduced and native fields. Breeding season bird diversity and total abundance did not differ among cover types or between introduced and native fields. Grasshopper Sparrows (Ammodramus savannarum), Cassin's Sparrows (Aimophila cassinii), and Western Meadowlarks (Sturnella neglecta) accounted for more than 90% of breeding season detections. Grasshopper Sparrows were the most abundant and found in all cover types. Cassin's Sparrows were 38% to 170% more abundant among the native seed mix without buffalograss (Buchloe dactyloides) compared to 3 other cover types. Although this association was statistically lost when cover types were pooled into introduced or native fields (U = 93.5, P = 0.91), the species was still 50% more abundant among native CRP than introduced CRP fields. Meadowlarks occurred ubiquitously but at very low numbers during the breeding season. During winter, avian abundance was 44% greater among native CRP than introduced CRP fields. Meadowlarks, Horned Larks (Eremophila alpestris), and Savannah Sparrows (Passerculus sandwichensis) accounted for 94% of all winter detections. Meadowlarks occurred ubiquitously, but Horned Larks and Savannah Sparrows were 157% and 96% more abundant, respectively, among native CRP than introduced CRP fields. Our data suggest that monocultures of introduced grasses may benefit some bird species but also that native seed mixes may have a more positive influence through increased diversity and abundance of grassland birds. However, pooling cover types into the broader categories of introduced or native grasses may dampen or occlude biologically meaningful results. It may be prudent to avoid broad categorization of CRP fields based solely on native or introduced grass cover when assessing habitat associations of grassland birds. |
| Management Implications: | An important point regarding our data on Cassin's Sparrows concerns resolution of habitat types. Although Cassin's Sparrows were more abundant in native-A fields, the ability to discern their association with heterogeneous mixes of native species was lost when cover types were pooled into the coarser categories of introduced or native field types. Thus assessment of Cassin's Sparrow use of CRP fields, and perhaps use by other grassland species, may require examination at finer resolutions than the broad categories of introduced or native field types. Our data suggest that no one seeding type is most attractive to grassland passerines in general but that CRP fields function as an important conservation tool. Similar to our study, other researchers found that CRP fields planted with mixtures of native grasses promoted increased avian abundance, diversity, use, and production compared to monocultures of introduced grass (Delisle and Savidge 1997, Davis and Duncan 1999, McCoy et al. 2001). In comparison to introduced monocultures, native seed mixes on CRP fields may have more positive influences for grassland birds. Pooling of cover types into the broader categories of introduced or native grasses risks dampening or occluding biologically meaningful results in characterizing vegetative characteristics or avian abundances in CRP fields of different grass compositions. For this reason, it would be prudent to avoid broad categorization of CRP lands as only introduced or native fields when assessing the value of different CRP field cover types. |
| Citation: | Thompson, T. R., C. W. Boal, and D. Lucia. 2009. Grassland bird associations with introduced and native grass conservation reserve program fields in the southern High Plains. Western North American Naturalist 69:481-490. |
| Title: | Toward increasing avian diversity: urban wildscapes programs |
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| Journal/Year: | Urban Ecosystems/2009 |
| View: | Visit Springer Link- Toward increasing avian diversity: urban wildscapes programs |
| Author(s): | Amanda L. Aurora|Thomas R. Simpson|Michael F. Small|Kelly C. Bender |
| Keywords: | avian diversity|urban|wildscapes|neigborhood |
| Abstract: | Residential development in urban and suburban settings is a major cause of habitat change affecting avian communities. The effects from land-clearing prior to initiation of construction, followed by landscaping focused on traditional aesthetics, has reduced habitat diversity at multiple levels. These residential developments generally emphasize the use of ornamental, nonindigenous vegetation with little to no concern for native species and natural vegetation parameters. As a result, avian community composition and diversity is changed. We compared avian communities at three sites in Bexar County, Texas; two residential neighborhoods in the city of San Antonio and an unincorporated undeveloped site, Government Canyon State Natural Area. The residential neighborhoods were a Texas Parks and Wildlife Department certified wildscapes development and a traditionally developed neighborhood. Bird abundance and species richness in the neighborhoods were greater than at Government Canyon State Natural Area (P < 0.01), but no differences existed between the neighborhoods. Bird diversity was greatest at the wildscapes neighborhood (P < 0.01). Further, bird diversity did not differ between the traditional neighborhood and the natural area. Evenness differed among sites (P = 0.006) with the natural area having the greatest value. Bird diversity measures correlated with woody plant density and vertical cover (r = 0.358 to 0.673, P < 0.05) at residential sites. Residential areas incorporating natural landscapes into their design attracted a greater variety of birds than traditionally landscaped residential areas. |
| Management Implications: | Our results are consistent with research linking urban and suburban development and the intermediate disturbance hypothesis (Blair 1996, Marzluff 2005, McKinney 2002). McKinney (2002) suggests the most efficient conservation strategy for maintaining species richness within housing developments is to retain predevelopment vegetation. This practice, incorporated in development of WCN, represents an intermediate stage of neighborhood development compared to traditional construction techniques which remove existing vegetation to facilitate construction. Since completion of our study, five additional neighborhoods have been certified as Texas Wildscapes. Additional studies are needed to evaluate overall program effectiveness, but our study indicates the Texas Wildscapes program and similar programs have the potential to provide significant benefits to native wildlife species in residential areas. |
| Citation: | Aurora, A. L., T. R. Simpson, M. F. Small, and K. C. Bender. 2009. Toward increasing avian diversity: urban wildscapes programs. Urban Ecosystems 12:347-358. |
| Title: | Factors influencing the occurrence of inundated playa wetlands during winter on the Texas High Plains |
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| Journal/Year: | Wetlands/2011 |
| View: | Visit Springer Link - Factors influencing the occurrence of inundated playa wetlands during winter on the Texas High Plains |
| Author(s): | William P. Johnson|Mindy B. Rice|David A. Haukos|Philip P. Thorpe |
| Keywords: | hydrology|midwinter waterfowl survey|spatial model|Texas High Plains |
| Abstract: | Playas form the dominant wetland system of the High Plains portion of the western Great Plains of the United States. Ecologically functional playas interact with all other ecosystems of the region to support the biodiversity of the region. Frequency and duration of playa inundation (i.e., hydroperiod) are major influences on the spatial and temporal distribution of flora and fauna in the region. We used a 10-year data set recorded during the annual Midwinter Waterfowl Survey on frequency and spatial distribution of inundation of 221 playa wetlands on the Texas High Plains (THP) to develop models of factors influencing the probability of a playa being flooded during January. We used a generalized estimate equation model with repeated measures and a logistic link to evaluate the relative influence of proportion of watershed in grass, proportion of watershed in crop, expected average annual rainfall, previous year's rainfall, and playa size on the probability of a playa being inundated during January. Of the 221 survey playas, 67% were inundated during January in ≥ 1 year; 33% of the playas never contained water in January during the study period. Our selected model indicated that the proportion of cropland in the watershed, playa size, the previous year's total rainfall, and mean annual rainfall as measured during the 10-years were the best indicators of a playa being inundated during January. Proportion of cropland in the watershed had a negative effect, whereas the other factors were positively related to the probability of being inundated. The probability of a playa being inundated during January increases from west to east across the THP. On average, we would expect individual playas to be inundated during January once every 7 to 10 years, with < 35% of the playas expected to be inundated in greater than 1 year out of 5. Hydrologic function is diminished in playas with cropland watersheds. Conservation efforts should concentrate on playas with grassland watersheds and located in regions of increased probability of being inundated during January. |
| Management Implications: | Our survey results exemplify the dynamic nature of playas. On average, any playa on the THP will be inundated during January only 1 out of 7 years. Furthermore, it is unlikely under natural conditions for an individual playa to be inundated in January during consecutive years. Conservation efforts for playas must recognize this natural variation and incorporate this dynamic into plans for conservation. Conservation of playas, through easements, acquisition or other means, should be focused on those with a large proportion of grassland in their watershed (Tsai et al. 2007). Conservation efforts should include playas occurring in eastern and northeastern THP as well, as they have a greater likelihood of being wet and providing habitat for wintering waterfowl and other wetland-dependent wildlife. |
| Citation: | Johnson, W. P., M. B. Rice, D. A. Haukos, and P. P. Thorpe. 2011. Factors influencing the occurrence of inundated playa wetlands during winter on the Texas High Plains. Wetlands 31:1287-1296. |
| Title: | Impacts of introduced grasses on breeding season habitat use by northern bobwhite in the south Texas plains |
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| Journal/Year: | Journal of Wildlife Management/2011 |
| View: | Visit Wiley Online Library - Impacts of introduced grasses on breeding season habitat use by northern bobwhite in the south Texas plains |
| Author(s): | Joseph P. Sands|Leonard A. Brennan|Fidel Hernandez|William P. Kuvlesky, Jr.|James F. Gallagher|Donald C. Ruthven, III|James E. Pittman, III |
| Keywords: | buffelgrass|Colinus virginianus|Eragrostis lehmanniana|introduced grasses|lehmann lovegrass|northern bobwhite|Pennisetum ciliare|saddlepoint approximation|South Texas plains |
| Abstract: | Introduced grasses may affect diversity of native fauna and flora adversely, and disrupt ecosystem processes. Many rangelands in South Texas have been seeded to or have been colonized by buffelgrass (Pennisetum ciliare) and Lehmann lovegrass (Eragrostis lehmanniana), perennial bunchgrasses native to Africa. The objective of this research was to quantify impacts that these 2 species of introduced grasses may have on northern bobwhite (Colinus virginianus) habitat use on South Texas rangelands during the breeding period (Apr-Aug).We evaluated the effects of buffelgrass and Lehmann lovegrass on northern bobwhite nest habitat (n = 35 nests) and general habitat use sites (n = 86 radiomarked quail) with logistic regression and habitat selection functions based on simple saddlepoint approximations. Buffelgrass was used as a nesting substrate at 11% of nests; however, vegetation height and visual obstruction between 1 cm and 30 cm were the best predictors of nest site use. Areas of introduced grass coverage ≥ 15-20% were avoided by northern bobwhites at general habitat use organism-centered points, but not at nest site use points. Introduced grass coverage and forb coverage were the best predictors of general habitat use, and bobwhites avoided areas with ≥ 18% introduced grass cover. These results suggest that avoidance of areas with extensive introduced grass cover may indicate a reduction in usable habitat space for northern bobwhite in the western South Texas plains. Maintaining native grass stands while implementing localized control of introduced grasses could be used as a strategy to promote habitat for northern bobwhites. |
| Management Implications: | Microhabitats composed of introduced grasses can provide usable space for some aspects of northern bobwhite life history (e.g., nesting), but not others (e.g., general habitat use). With respect to general habitat use, relatively small amounts of introduced grasses (e.g., < 10%) may not pose an immediate threat to northern bobwhite habitats, but promoting native grass stands on a landscape scale, and implementing localized control methods for introduced grasses, could help maximize usable space for northern bobwhites. Complete elimination of introduced grasses on a landscape scale is improbable, but managers and landowners interested in providing northern bobwhite habitat should determine the abundance of introduced grass on their lands, and work to control the spread of these grasses. |
| Citation: | Sands, J. P., L. A. Brennan, F. Hernandez, W. P. Kuvlesky, Jr., J. F. Gallagher, and D. C. Ruthven, III. 2011. Impacts of introduced grasses on breeding season habitat use by northern bobwhite in the south Texas plains. Journal of Wildlife Management 76:608-618. |
| Title: | Fate of phosphorus in Richland Creek WMA constructed wetland for water reuse |
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| Journal/Year: | Thesis, TPWD Final Report/2012 |
| View: | Download Shartle_2012_PhosphorusRichlandWMA.pdf |
| Author(s): | T. Wells Shartle |
| Citation: | Shartle, T. W. 2012. Fate of phosphorus in Richland Creek WMA constructed wetland for water reuse. Thesis, Stephen F. Austin State University, Nacogdoches, TX, USA. |
| Title: | Implications of coastal wetland management to nonbreeding waterbirds in Texas |
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| Journal/Year: | Wetlands/2012 |
| View: | Visit Springer Link - Implications of coastal wetland management to nonbreeding waterbirds in Texas |
| Author(s): | Owen N. Fitzsimmons|Bart M. Ballard|M. Todd Merendino|Guy A. Baldassarre|Kevin M. Hartke |
| Keywords: | aquatic invertebrates|marsh management|Texas coast|waterbirds |
| Abstract: | Texas coastal marshes have declined in number and quality, prompting the widespread use of levees and water control structures to create or enhance coastal marsh habitat. In particular, management techniques that control water to provide fresh (< 0.5 ppt) and intermediate (0.5-5 ppt) marsh in a landscape dominated by brackish and saline marsh. However, research is needed to assess the effectiveness of these techniques in providing waterbird habitat. During 2007-09 along the central Texas Coast, we investigated the effects of marsh management on bird, plant, and aquatic invertebrate communities by comparing leveed areas within the coastal marsh that received water level and mechanical management, to adjacent nonmanaged marsh that received no hydrologic or mechanical manipulations. Managed marshes supported more bird species, greater waterbird densities, greater plant diversity, and greater aquatic invertebrate biomass than nonmanaged sites. However, nonmanaged wetlands supported greater densities and more species of secretive marsh birds (e.g., rails). Management of coastal marsh that reduces water salinities and suppresses plant succession appears to be a possible way to mitigate the effects of declines in fresh and intermediate marsh on nonbreeding waterbirds. |
| Management Implications: | Our findings suggest that proper management of wetlands along the Texas coast can provide productive and diverse habitat for many wetland bird species. Greater invertebrate biomass and available energy, as well as greater seasonal variation in hydrology may have contributed to the higher bird species richness, bird diversity, and waterbird densities that we observed in managed wetlands. Marsh management techniques that reduce water salinities and suppress plant succession appear to create habitat for a suite of species that are not present in adjacent saltwater marshes. However, the value of nonmanaged marsh also was evident, as nonmanaged areas supported the majority of secretive marsh bird species (e.g., rails, bittern, sparrows) detected and greater marsh bird densities throughout the study. Future comparative studies should use extended monitoring efforts to account for broader temporal changes in plant and bird communities, and to better assess patterns across years. Also, investigating differences in foraging values of managed and nonmanaged marshes to different groups of waterbirds would help explain differences in their use, as aquatic invertebrates represent only a portion of the foods available to waterbirds in wetlands. Evaluating stopover duration, vital rates, or mass change of birds using managed and unmanaged marsh would allow a stronger assessment as to the quality of these habitats to migratory and wintering birds. Finally, major events such as hurricanes can provide valuable pre- and post event research opportunities, and future monitoring in these areas might provide clearer understanding of natural disturbances. Depending on specific objectives, managed wetlands on the Texas Coast can provide important habitat during crucial non-breeding periods to a large and diverse assemblage of birds, some of which are of high priority for conservation. Marsh management techniques present managers with an effective way to alleviate the negative effects of recent loss and degradation of freshwater and intermediate marsh on the Texas Coast (Moulton et al. 1997). The benefits of such practices are justification for the establishment of managed marshes in conjunction with the conservation of natural areas to improve habitat diversity for wetland birds at the local and landscape level on the Texas Coast. |
| Citation: | Fitzsimmons, O. N., B. M. Ballard, M. T. Merendino, G. A. Baldassarre, and K. M. Hartke. 2012. Implications of coastal wetland management to nonbreeding waterbirds in Texas. Wetlands 32:1057-1066. |
| Title: | Understanding functional connectivity in shortgrass and mixedgrass prairies using the swift fox as a model organism |
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| Journal/Year: | Dissertation/2012 |
| View: | Download Schwalm_2012_PrairiesSwiftFoxDissertation.pdf |
| Author(s): | Donelle L. Schwalm |
| Abstract: | Habitat fragmentation and loss are the greatest sources of biodiversity loss today. The negative relationship between these phenomena and myriad ecological processes are well-documented. Chief amongst these impacts is the disruption of dispersal regimes, resulting in isolated or semi-isolated groups. Reduced dispersal in turn negatively influences gene flow between groups of individuals, resulting in reduced genetic diversity, increasing risk of inbreeding depression and, ultimately, heightened extinction risk. Thus, maintaining functional connectivity in ecosystems is high on the list of conservation priorities. The Great Plains is a vast ecosystem characterized by habitat fragmentation natural and anthropogenic in origin. Remnant shortgrass and mixedgrass prairies, in which this study occurs, have been reduced to < 50% of their previous extensive geographic area, largely due to agricultural development. Anthropogenic impacts on connectivity are predicted to increase, resulting in loss of up to 50% of remnant native grasslands. Thus, understanding these factors' influence on grassland connectivity is critical for conservation and management in both contemporary and future time scales. Here, I employed a landscape genetics approach to address a series of objectives, which include assessing current and historic genetic diversity and structure in swift fox populations, relating gene flow and genetic structure patterns to landscape influences, and providing insight into conservation needs for the species. In addition, I used the swift fox as a model species to elucidate connectivity patterns across two focal areas in the shortgrass and mixedgrass prairies, ultimately presenting functional connectivity maps for these regions. Finally, I developed a new method for studying connectivity networks in fragmented populations with empirically derived cost metrics, and demonstrated its utility for identifying movement corridors using leastcost path modeling; this analysis was conducted in a fragmented swift fox population wherein genetic diversity appears to be linked to inter-population movement; thus identification of movement corridors is a critical conservation need locally. |
| Management Implications: | Movement between subgroups in the regional population appears to be a critical process for maintaining genetic diversity in fragmented habitats. Thus, swift fox management should emphasize connectivity conservation at a multi-state level. This will require identifying and conserving extant corridors, which may be few in number and narrow in width in this impacted region. Sohl et al. (2012) predict as much as 50% of remnant grassland will be lost within the region in the next ~90 years; preemptive grassland conservation is therefore critical for connectivity conservation. Although patches of grassland are conserved as part of the Forest Service National Grassland system (e.g., the Rita Blanca and Kiowa National Grasslands), the vast majority of shortgrass and mixedgrass prairie in the study area is privately owned and vulnerable to further development. Thus, managing for connectivity will require coordination between private landowners and state and federal agencies for success. In the study area, swift fox management varies by state. In all four states the swift fox is listed as a furbearer; however, in Colorado and Oklahoma the season is closed, whereas in New Mexico and Texas, swift fox can be harvested during regulated seasons. These results imply that genetic diversity in the eastern group, which exists primarily in Texas, is maintained by high immigration from the central group; furthermore, population numbers in the Texas population appear to benefit from immigration, with nearly 30% of resident foxes originating from other sources. At minimum, I encourage managers to afford the swift fox in Texas greater protection. Reliance on support from other populations is a tenuous option, given anticipated future connectivity reductions in the face of grassland conversion. Given the aforementioned limitations of the sample distribution in New Mexico, I am hesitant to extend recommendations for this region, but urge caution in management decisions, given the limited indication of gene flow my results imply. |
| Citation: | Schwalm, D. L. 2012. Understanding functional connectivity in shortgrass and mixedgrass prairies using the swift fox as a model organism. Dissertation, Texas Tech University, Lubbock, USA. |