The emblematic minnows of the North American Great Plains: A synthesis of threats and conservation opportunities

Abstract

Anthropogenic changes to the Great Plains rivers of North America have had a large, negative effect on a reproductive guild of pelagic‐broadcast spawning (PBS) cyprinid fishes. The group is phylogenetically diverse, with multiple origins of the PBS mode. However, because of incomplete life‐history information, PBS designation often relies only on habitat and egg characteristics. We identified 17 known or candidate PBS fishes and systematically synthesized the literature on their biology and ecology in relation to major threats to persistence. Research output on an individual species was unrelated to conservation status, but positively correlated with breadth of distribution. The PBS species have opportunistic life‐history strategies and are typically short‐lived (generally 1–3 years) fishes. Many PBS species have truncated ranges showing declines in both distribution and abundance, especially those endemic to the Rio Grande catchment. Fundamental habitat associations are unknown for many species, particularly regarding seasonal shifts and early life stages. Critical thermal tolerances have been quantified for five PBS species and are generally >35°C. Turbidity and salinity changes are linked to responses at multiple life stages, but information is lacking on interactions between water quality and quantity. Hydrologic alteration appears to be a primary threat to PBS species, through complex interactions with landscape fragmentation, and habitat change. We highlight areas where scientific and management communities are lacking information and underline areas of potential conservation gain.

Extreme drought causes fish recruitment failure in a fragmented Great Plains riverscape

“…Raw GSI data are summarized with generalized additive models (GAMs), and model fits (black lines) with 95% confidence intervals (grey areas) are shown. These results highlight recent calls for greater investigation of linkages between environmental fluctuations and dynamics of early life stages to promote conservation of imperilled fishes Worthington et al, 2018). Length data were binned by 2-mm categories for length-frequency plots and relative frequencies are shown chub and mostly age 2 silver chub were collected, indicating that the existing stocks were likely hold-overs from the previous year.…”

“…Research from the Great Plains suggests that fishes with planktonic ova are much more sensitive to low flows compared with fishes with demersal ova (Perkin, Gido, Costigan, et al, 2015;Perkin, Gido, Cooper, et al, 2015;Worthington et al, 2018). Research from the Great Plains suggests that fishes with planktonic ova are much more sensitive to low flows compared with fishes with demersal ova (Perkin, Gido, Costigan, et al, 2015;Perkin, Gido, Cooper, et al, 2015;Worthington et al, 2018).…”

“…Dryland river fishes must contend with truncated expansions and accelerated contractions within habitat arenas that are severely fragmented by instream structures that do not allow downstream movement or upstream recolonization (Lehner et al, 2011;Perkin & Gido, 2011. Previous research in the Great Plains has demonstrated fish diversity loss caused by interactions between spawning mode, habitat isolation, and low flow disturbance (Perkin, Gido, Cooper, et al, 2015;Worthington et al, 2018). Previous research in the Great Plains has demonstrated fish diversity loss caused by interactions between spawning mode, habitat isolation, and low flow disturbance (Perkin, Gido, Cooper, et al, 2015;Worthington et al, 2018).…”

Asymmetric introgression between fishes in the Red River basin of Texas is associated with variation in water quality

“…Dams disrupt the habitat and environmental heterogeneity of rivers, homogenizing habitats (Santucci, Gephard, & Pescitelli, ), which can lead to an increase in introgressive hybridization (Hasselman et al, ; Seehausen, Takimoto, Roy, & Jokela, ). Thus, it is possible that the construction of Lake Texoma could have restricted a species of mobile Macrhybopsis (Wilde, ; Worthington et al, ) upstream and, along with altering upstream habitats (e.g., deeper water, more similar to habitats associated with shoal chubs; Eisenhour, ), could have anthropogenically inflated shoal chub numbers in the zone.…”

The accuracy of ecological flow metrics derived using a physics‐based distributed rainfall–runoff model in the Great Plains, USA

“…The importance of the reduced accuracy at finer temporal resolutions or the ability to utilize predicted flow data aggregated to coarser time steps is dependent on the life‐history requirements of the organisms against which the modelled flow is to be compared. In the context of fishes, the magnitude and timing of high‐flow pulses, thought to trigger synchronous spawning in pelagic‐broadcast spawning cyprinids of the Great Plains (Worthington et al, ), are unlikely to be described by models operating at coarser temporal scales. This is problematic for many prairie fishes where spawning events are typically concentrated in response to hydrologic events or under coupled conditions created by both water temperature and discharge (Rabeni, ).…”