Trait‐based and multi‐scale approach provides insight on responses of freshwater mussels to environmental heterogeneity

Mitchell, Zachary A.; Cottenie, Karl; Schwalb, Astrid N.

doi:10.1002/ecs2.4533

Cited by 4 publications

(4 citation statements)

References 105 publications

(147 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is especially concerning given that nearly half of the mussels found during surveys were L. bracteata, a Texas endemic that is found only in the Colorado River drainage and is a candidate for endangered species listing (USFWS, 2021). Catch per unit effort in the middle segment of the San Saba during our study (0.8 mussels/ p-h) was much lower than in the upper and lower segments of the river, where CPUEs of 7-20 mussels/ p-h have been noted (Mitchell et al, 2023;Randklev et al, 2018).…”

Section: Discussioncontrasting

confidence: 55%

When rivers run dry: Perennial pools as ecological refuges for freshwater mussels during drought

Cushway,

Schwalb

2023

Freshwater Biology

Self Cite

View full text Add to dashboard Cite

As the intensity and frequency of drought and drying events are predicted to increase globally with climate warming and increasing human water usage, there is an urgent need to understand what kind of habitats may serve as refuges for organisms to withstand adverse effects. When flows decrease in rivers, disconnected pools may provide critical habitat for survival of aquatic organisms such as freshwater mussels, a highly imperilled group for which drought and dewatering pose a major threat. The objective of this study was to (1) examine whether pools serve as ecological refuges for freshwater mussels (Bivalvia: Unionidae) in drought‐stricken streams by surveying mussel distribution in an intermittent section (i.e., a section that regularly goes dry) of the San Saba River, Texas, and (2) examine the habitat characteristics that influence whether a pool functions as a refuge. We found that pool dimensions, thermal conditions, past dryness (number of years a pool was dry between 2004 and 2020), underlying geology, and aquatic and riparian vegetation influence the abundance and species richness of freshwater mussels in pools that may serve as important refuges for mussels to avoid desiccation and lethal high temperatures. Despite this, abundances and richness of mussels were low at all sites. Our results suggest that pools that retain water during drought conditions (i.e., perennial pools) may serve as ecological refuges for globally imperilled organisms such as freshwater mussels on shorter timescales (e.g., days to years). Protection and prioritisation of maintaining suitable conditions in refuge pools may help mussels persist as drought and drying issues become more pervasive in aquatic ecosystems. However, if there is a limited number of isolated pools that only allow the survival of a small number of mussels, then these pools cannot prevent overall declines of mussels in drying rivers. Better management of surface water and groundwater in anthropogenically impacted systems could ensure the flowing conditions that are needed to protect mussels in the face of climate change.

show abstract

Section: Discussioncontrasting

confidence: 55%

When rivers run dry: Perennial pools as ecological refuges for freshwater mussels during drought

Cushway,

Schwalb

2023

Freshwater Biology

Self Cite

View full text Add to dashboard Cite

show abstract

“…bracteata and U . imbecillis [ 60 ]). Hence, if many of the mussels found during this study occupied flow refuges in pools that protect them from the effects of shear stress and stream power during high flows, conditions during low flows such as adequate depth, which influences refuge potential during drought, may become more influential [ 87 , 88 ].…”

Section: Discussionmentioning

confidence: 99%

“…All freshwater mussel data was collected under a scientific collection permit issued to Astrid Schwalb by the Texas Parks and Wildlife Department. Survey methods and data are publicly available in [ 60 , 61 ] and in S1 Appendix .…”

Section: Methodsmentioning

confidence: 99%

“…g ., riffle, pool, run) for mussel presence to examine differences based on scale ( Fig 1 ). Surveyed sites were grouped together based on the mesohabitat recorded during sampling in [ 60 ] and compared to aerial imagery [ 63 ]. If a site was identified as the same mesohabitat type as a site directly upstream or downstream, with a continuous channel form in aerial imagery, the sites were combined into a single channel unit based on that mesohabitat.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Go with the flow: Impacts of high and low flow conditions on freshwater mussel assemblages and distribution

Cushway,

Harris,

Piercy

et al. 2024

PLoS ONE

Self Cite

View full text Add to dashboard Cite

Understanding the drivers of distribution and assemblage composition of aquatic organisms is an important aspect of management and conservation, especially in freshwater systems that are inordinately facing increasing anthropogenic pressures and decreasing biodiversity. For stream organisms, habitat conditions during high flows may be impossible to measure in the field, but can be an important factor for their distribution, especially for less mobile organisms like freshwater mussels. Hence, the objective of this study was to use a two dimensional HEC-RAS model to simulate hydraulic conditions during high and baseline flows (flows approx. 10–600 x and 0.7 x median daily flows respectively) in a 20 km segment in the San Saba River, Texas in combination with existing mussel survey data from 200 sites (collected every 100m) to 1) examine whether hydraulic conditions differed between areas of increased mussel richness and diversity (referred to as hotspots) and other sites, and 2) understand how well site occupancy and species abundance could be explained by hydraulic conditions occurring under different flow conditions. The results showed that richness and diversity hotspots occurred in deeper areas with lower shear stress, stream power, and Froude number during both high and low flows. Occupancy could be predicted with 67–79% accuracy at the site scale and 60–70% accuracy at the mesohabitat scale (∼20 to 1200 m long). In addition, hydraulic conditions across flow scenarios explained up to 55% of variation in species abundances, but predictions were less successful for species often observed to occupy micro-scale flow refuges such as bedrock crevices. The results indicate that pools may serve as important refuge for all species during both high and low flow events, which may be relatively unique to bedrock-dominated systems. Understanding hydraulic conditions that occur at extreme flows such as these is important given that the frequency and magnitude of such events are increasing due to climate change.

show abstract