Population viability analysis of the Endangered shortnose sturgeon

Jager, Henriëtte I.; Bevelhimer, Mark S.; Peterson, Douglas L.

doi:10.2172/1047606

Cited by 2 publications

(1 citation statement)

References 34 publications

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“…Because bottom and surface measurements were not significantly different, we used an average of the two, if both were available, and the single available measurement, if not. Longitudinal variation in temperature was not significant, but season explained at least 94% of variation in water temperatures (sine term in equation 3) measured by Jager et al (2011Jager et al ( ) in 2007Jager et al ( -2009. In the Ogeechee River, water temperature also showed a significant decrease in response to increased total flow.…”

Section: Dynamic Habitat Qualitymentioning

confidence: 90%

A Population Model to Assess Influences on the Viability of the Shortnose Sturgeon Population in the Ogeechee River, Georgia

et al. 2013

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Southern populations of the federally endangered Shortnose Sturgeon Acipenser brevirostrum are considered to be at greater risk of extirpation than northern populations. Our study focused on the Ogeechee River, Georgia, a small, undeveloped, coastal river that supports a population with fewer than 300 Shortnose Sturgeon. We designed a population viability analysis (PVA) model to represent and quantify the demographic influences of three factors (poor water quality, intrusion of saline water via rice canals, and incidental harvest) on the viability of this population. As an isolated population, only 75% of simulated populations persisted beyond a 20‐year time horizon with all factors simulated. However, immigration from the Altamaha River may help to support the population. We quantified population persistence with and without simulating each factor and found that (1) incidental harvest had no effect on simulated persistence, (2) poor water quality decreased simulated persistence by 29%, primarily due to low oxygen conditions in summer, and (3) roughly one‐third of this effect was attributed to rice canals (premature exposure of juveniles to high salinities). Simulated recruitment to age 1 was limited by a habitat squeeze between density‐dependent starvation upstream near the spawning grounds and premature exposure to salinity downstream. These results highlight a need for research on availability of summer refuge and freshwater rearing habitat. As these results derived from a PVA model, which required many assumptions, they should be considered preliminary. Further field research is needed to confirm those results where it is possible to test intermediate predictions. We conclude by suggesting that efforts to maintain or increase the number of viable populations of Shortnose Sturgeon in southern U.S. rivers will probably require an understanding of (1) source‐sink dynamics between populations in rivers with access to adequate freshwater rearing habitat and those without, and (2) the effects of climate change.

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Section: Dynamic Habitat Qualitymentioning

confidence: 90%

A Population Model to Assess Influences on the Viability of the Shortnose Sturgeon Population in the Ogeechee River, Georgia

et al. 2013

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Landscape Influences on Headwater Streams on Fort Stewart, Georgia, USA

Jager

Bevelhimer

King

et al. 2011

Environmental Management

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Military landscapes represent a mixture of undisturbed natural ecosystems, developed areas, and lands that support different types and intensities of military training. Research to understand water-quality influences of military landscapes usually involves intensive sampling in a few watersheds. In this study, we developed a survey design of accessible headwater watersheds intended to improve our ability to distinguish land-water relationships in general, and training influences, in particular, on Fort Stewart, GA. We sampled and analyzed water from watershed outlets. We successfully developed correlative models for total suspended solids (TSS), total nitrogen (TN), organic carbon (OC), and organic nitrogen (ON), which dominated in this blackwater ecosystem. TSS tended to be greater in samples after rainfall and during the growing season, and models that included %Wetland suggested a "build-and-flush" relationship. We also detected a positive association between TSS and tank-training, which suggests a need to intercept sediment-laden runoff from training areas. Models for OC showed a negative association with %Grassland. TN and ON both showed negative associations with %Grassland, %Wetland, and %Forest. Unexpected positive associations were observed between OC and equipment-training activity and between ON and %Bare ground + Roads. Future studies that combine our survey-based approach with more intensive monitoring of the timing and intensity of training would be needed to better understand the mechanisms for these empirical relationships involving military training. Looking beyond local effects on Fort Stewart streams, we explore questions about how exports of OC and nitrogen from coastal military installations ultimately influence estuaries downstream.

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Population viability analysis of the Endangered shortnose sturgeon

Cited by 2 publications

References 34 publications

A Population Model to Assess Influences on the Viability of the Shortnose Sturgeon Population in the Ogeechee River, Georgia

A Population Model to Assess Influences on the Viability of the Shortnose Sturgeon Population in the Ogeechee River, Georgia

Landscape Influences on Headwater Streams on Fort Stewart, Georgia, USA

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