Hydrologic Influences of the Blanco River on the Trinity and Edwards Aquifers, Central Texas, USA

Smith, Brian A.; Hunt, Brian B.; Andrews, A. G.; Watson, Jeffery A.; Gary, Marcus O.; Wierman, Douglas A.; Broun, Alex S.

doi:10.1007/978-3-642-17435-3_18

Cited by 2 publications

(1 citation statement)

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“…The unique geologic structure of the Edwards Aquifer controls the direction of groundwater movement, with permeable rock units horizontally adjacent to less-permeable units along fractures and faults that may act as either barriers or conduits to groundwater flow depending on the nature of the fault (88)(89)(90). Patterns of subsurface flow may be locally complex (91,92), but in the southern segments water generally flows from areas of higher elevation in the southwest to discharge features in the northeast (36). Although the topographic boundaries between adjacent surface watersheds in the contributing zone of the Edwards Aquifer are well-defined, surface watershed boundaries may or may not be coincident with the extent of the underlying groundwater basins, especially where local geology is complex, for example in the northern segment of the Edwards (81,93).…”

Section: The Edwards-trinity Aquifer Systemmentioning

confidence: 99%

Species delimitation in endangered groundwater salamanders: Implications for aquifer management and biodiversity conservation

Devitt

Wright

Cannatella

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

100

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Groundwater-dependent species are among the least-known components of global biodiversity, as well as some of the most vulnerable because of rapid groundwater depletion at regional and global scales. The karstic Edwards–Trinity aquifer system of west-central Texas is one of the most species-rich groundwater systems in the world, represented by dozens of endemic groundwater-obligate species with narrow, naturally fragmented distributions. Here, we examine how geomorphological and hydrogeological processes have driven population divergence and speciation in a radiation of salamanders (Eurycea) endemic to the Edwards–Trinity system using phylogenetic and population genetic analysis of genome-wide DNA sequence data. Results revealed complex patterns of isolation and reconnection driven by surface and subsurface hydrology, resulting in both adaptive and nonadaptive population divergence and speciation. Our results uncover cryptic species diversity and refine the borders of several threatened and endangered species. The US Endangered Species Act has been used to bring state regulation to unrestricted groundwater withdrawals in the Edwards (Balcones Fault Zone) Aquifer, where listed species are found. However, the Trinity and Edwards–Trinity (Plateau) aquifers harbor additional species with similarly small ranges that currently receive no protection from regulatory programs designed to prevent groundwater depletion. Based on regional climate models that predict increased air temperature, together with hydrologic models that project decreased springflow, we conclude that Edwards–Trinity salamanders and other codistributed groundwater-dependent organisms are highly vulnerable to extinction within the next century.

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