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HUC10 watersheds used to evaluate land use alterations for study sites from 1980 to 2012 (Appendix C). The red dots also represent the USGS stream gages used for Indicators of Hydrologic Alteration (IHA) statistics (Appendix D).

HUC10 watersheds used to evaluate land use alterations for study sites from 1980 to 2012 (Appendix C). The red dots also represent the USGS stream gages used for Indicators of Hydrologic Alteration (IHA) statistics (Appendix D).

Contexts in source publication

Context 1
... on the three upper watershed tributaries, the Llano, San Saba, and Pedernales Rivers, were sampled ( Figure 2, Appendix A). The San Saba River is formed at the confluence of the North Valley Prong and the Middle Valley Prong in Schleicher County. ...
Context 2
... use and land cover (LULC) changes were determined for 30 hydrologic unit code (HUC) 10 watersheds ( Figure 2) encompassing all study sites chosen based on previous collections by Edwards (1980Edwards ( ) during 1975Edwards ( -1978. Historical and present geospatial data were used to determine land use alteration and total watershed area. ...
Context 3
... of each LULC dataset is defined in Appendix F. Land use and land cover (LULC) data were evaluated for percent difference between two time periods in order to visualize the gradient in of disturbance in the Colorado River Basin. Percent changes in LULC within each HUC 10 watershed (Figure 2; Appendix G-H) were used as environmental variables for further analysis. ...
Context 4
... San Saba River and Llano River sub-watersheds showed the least amount of change out of all sub-watersheds of interest. Two HUC 10 watersheds encompass the city of Austin, Texas ( Figure 2) and over the thirty-year period HUC 10: 1209020504 showed little change in LULC, while HUC 10: 1209020503 showed a decrease (-3.6%) in high urban area and an increase (7.8%) in low urban area. Urbanization increases or shifts from low urban to high urbanized areas were greatest in two Pedernales River watersheds (HUC 10: 1209020601; HUC 10: 1209020602), two Colorado River watersheds (HUC 10: 1209030102; HUC 10: 1209030107) and one San Saba River watershed (HUC 10: 1209010905). ...
Context 5
... Bass mesohabitat associations were largely dominated by pool classed mesohabitat downstream (F3,12=6.74, P=0.01) of Bastrop (Figure 22), while mesohabitat associations in Bastrop were dominated by riffle (F 3,12=4.28, P=0.02). ...
Context 6
... association was largely dominated by sand and boulder with cobble being significantly selected (F3,12=10.86, P=0.001) for in downstream sites at LaGrange and Altair ( Figure 23). Gravel was selected in equal proportion across all sites and there was no significant difference in selection of any other dominated by sand and boulder with cobble being significantly selected (F3,12=10.86, ...
Context 7
... was selected in equal proportion across all sites and there was no significant difference in selection of any other dominated by sand and boulder with cobble being significantly selected (F3,12=10.86, P=0.001) for in downstream sites at LaGrange and Altair ( Figure 23).substrate type across sites. ...
Context 8
... and bedrock (F3,12=0.96, P=0.45) ( Figure 23). Figure 4. ...

Citations

... While the area was historically farm and ranch land, single-family home developments are now commonplace (Hill Country Alliance 2008). The associated increase in impervious surfaces from this change has altered the natural flow regime in portions of the Colorado River watershed (Pease et al. 2017(Pease et al. , 2018. With few exceptions, local land- development regulations and ordinances for protecting water quantity and quality are generally lacking, and further land development in sensitive areas (e.g., riparian areas or aquifer recharge zones) will likely have deleterious effects on groundwater and surface water systems. ...
... Many small springs and streams throughout Texas have experienced general declines in annual flows or ceased to flow permanently as a result of increased demands on groundwater (Bowles and Arsuffi 1993). Changes to Guadalupe Bass population structure resulting from altered hydrology have been hypothesized (Grabowski 2014a) but are largely unstudied, with a few exceptions (e.g., Edwards 1978;Groeschel 2013;Pease et al. 2017). Filling this knowledge gap would be critical to effectively managing populations. ...
... Filling this knowledge gap would be critical to effectively managing populations. Long-term reduction in base flow could decrease growth of Guadalupe Bass (Groeschel 2013) and ulti-mately change population structure (Pease et al. 2017). Reduction of spring flows would also likely negatively impact the 13 endemic species of fish in the Edwards Plateau ecoregion considered spring-associated obligates (Craig et al. 2016). ...
Chapter
Full-text available
The Colorado River of Texas originates in the northwest portion of the state and runs southeasterly across the environmentally sensitive Edwards Plateau ecoregion, eventually emptying into Matagorda Bay on the Gulf of Mexico. The Texas Parks and Wildlife Department (TPWD) and other conservation partners have worked for decades to conserve native fishes in the river and its associated estuary. The river and its tributaries are also the major water source for millions of people, and portions of the watershed are undergoing unprecedented human population growth and a concomitant increased demand for water. Drought, which is a frequent occurrence in Texas, exacerbates these effects. Providing adequate streamflow and water quality to conserve aquatic species while still fulfilling obligations for municipal, industrial , agricultural, hydropower, and recreational water use is increasingly challenging. Since the 1980s, the TPWD has promoted water management policies in the watershed to benefit aquatic life, conducted research to maintain a sound ecological environment for fish and other aquatic taxa, provided technical guidance and financial incentives to private landowners to improve land practices that benefit water quality and quantity, and improved public access to foster increased stewardship of the river. The TPWD has also collaborated with researchers to study the potential impacts of altered hydrology on two endemic, flow-dependent fish species, Guadalupe Bass Micropterus treculii and Blue Sucker Cycleptus elongatus. Two portions of the Colorado River watershed have been identified as native fish conservation areas in part for persistence of populations of these native fishes. Outcomes from these activities are now being leveraged using federally funded research and conservation delivery programs to further advance the conservation of native fish populations and other aquatic life in native fish conservation areas of the Colorado River watershed.
... . Habitat degradation, resulting from urbanization in central Texas, is a chronic threat to the conservation of Guadalupe Bass populationsCurtis et al. 2015;Pease et al. 2017). Blue Sucker is listed as State Threatened in Texas and of Special Concern in North America(Jelks et al. 2008), with early life history stages hypothesized as vulnerable to flow alteration(Adams et al. 2006).Threats to these focal fishes and other flow-dependent aquatic species in the Central Edwards Plateau Rivers and Lower Colorado River NFCAs are largely associated with increasing human populations and associated demands for surface and groundwater. ...
... Groeschel 2013, Pease 2017. The clear and fast-flowing headwater streams of the Central Edwards Plateau Rivers NFCA meet the habitat requirements of Guadalupe Bass, while river base flows are largely dependent on spring discharge from groundwater that is under increased threat of pumping due to human development pressures. ...
... Numerous springs and streams throughout Texas have experienced general declines in annual flows, or ceased to flow permanently as a result of groundwater pumping(Bowles and Arsuffi 1993). Long-term reductions in base flow could decrease growth of Guadalupe Bass(Groeschel 2013), and change their population structure(Pease et al. 2017).Reduction of spring flow would also likely negatively impact the thirteen endemic species of fish in the Edwards Plateau ecoregion that are considered spring-associated obligates(Craig et al. 2016).River flows in the Lower Colorado River NFCA downstream of the City of Austin are largely dependent on controlled releases from the upstream Highland Lakes. Unlike the fast flowing, narrow and clear headwater streams located in the Central Edwards Plateau Rivers NFCA, this portion of the river is relatively wide and slow moving with intermittent pools, riffles, occasional rapids, and intermittent boulder fields(Magnelia 2018). ...
Technical Report
Full-text available
Native Fish Conservation Areas of the southwestern USA consist of springs, ciénegas, creeks, rivers, and associated watersheds uniquely valued in preservation of freshwater fish diversity. These freshwater systems were identified through a spatial prioritization approach that identifies areas critically important to the long-term persistence of focal fish species. Through a shared mission of collaborative stewardship, conservation partnerships have formed among non-governmental organizations, universities, and state and federal agencies to plan and deliver actions to restore and preserve native freshwater fishes and aquatic habitats within the Native Fish Conservation Areas. Furthermore, the Native Fish Conservation Areas have increased awareness of the ecological, recreational, and economic values of freshwater systems in the region, and helped increase interest and capacity of local landowners, communities, and recreational users (e.g., paddlers, anglers) to act as advocates and local stewards of these systems. By facilitating partnership development, coordinating multi-species, watershed-based conservation planning, and leveraging technical and financial resources toward strategic conservation investments, Native Fish Conservation Areas have served as a catalyst for collaborative, science-based stewardship of native freshwater fishes and aquatic habitats in the southwestern USA. Efforts described herein to prioritize and deliver a network of Native Fish Conservation Areas in the southwestern USA offer a successful case study in multi-species and watershed approaches to freshwater fish conservation transferrable to other states and regions of the USA. This report offers a synthesis of recent (2011-2018) multi-species aquatic assessments, Native Fish Conservation Area prioritizations, conservation planning, and conservation delivery within the southwestern USA explicitly focused on implementation of the Native Fish Conservation Areas approach.
Article
Full-text available
Predicting how stream fishes may respond to habitat restoration efforts is difficult due, in part, to an incomplete understanding of how basic biological parameters such as growth and ontogenetic habitat shifts interact with flow regime and riverscape ecology. We assessed age-specific Guadalupe Bass Micropterus treculii habitat associations at three different spatial scales in the South Llano River, a spring-fed stream on the Edwards Plateau of central Texas, USA, and the influence of habitat and flow regime on growth. Substrates were classified using a low-cost side-scan sonar system. Scale microstructure was used to determine age and to back-calculate size at age. Over 65% of captured Guadalupe Bass were age-2 or age-3, but individuals ranged from 0-7 years of age. Habitat associations overlapped considerably among age classes 1-3+, but age-0 Guadalupe Bass tended to associate with greater proportions of pool and run mesohabitats with submerged aquatic vegetation. While habitat metrics across multiple scales did not have a large effect on growth, river discharge was negatively correlated with growth rates. Understanding age-specific Guadalupe Bass habitat associations at multiple scales will increase the effectiveness of restoration efforts directed at the species by assisting in determining appropriate ecological requirements of each life-history stage and spatial scales for conservation actions.