Prairie Stream Research Articles

A synthesis of the characteristics and drivers of introduced fishes in prairie streams: can we manage introduced harmful fishes in these dynamic environments?

A synthesis of the characteristics and drivers of introduced fishes in prairie streams: can we manage introduced harmful fishes in these dynamic environments?

Effects of cattle intrusion on environmental conditions and fish assemblages of temperate neotropical prairie streams

Effects of cattle intrusion on environmental conditions and fish assemblages of temperate neotropical prairie streams

Kansas Prairie Streams Are Getting Choked, Maybe for Good

A herculean effort to fight back woody plants in the Konza Prairie has largely failed. The outcome shows how difficult it can be to retore these ecosystems.

Bank erosion and erosion processes from dendrogeomorphology in southern U.S. prairie streams

AbstractStreambank erosion processes influence the amount of soil material contributed to rivers and sedimentation rates in receiving reservoirs. However, the amount of data on bank erosion rates is limited both in range and extent affecting planning for mitigation and watershed management. Dendrogeomorphology is used to determine the date of wood anatomy changes in annual growth increments of roots exposed by erosion of stream banks that when coupled with measurement of the distance of roots to the channel side can be used to calculate the bank retreat rate. Erosion rates derived from dendrogeomorphology are important because these provide erosion data over longer time scales (decades). Here, we use this method to quantify erosion for three different sized watersheds (4 to 3781 km2) located in the water‐scarce southern U.S. prairies that are heavily reliant on surface water and reservoir storage. From 49 roots from the two smaller drainages, erosion ranged from 1.5 to 25.4. For 19 roots collected from the larger subbasin erosion rates were larger ranging from 7.4 to 325.0 cm/years with the larger values and variance associated with two high‐flow events that occurred a year before sampling. We also found differences in straight and meandering portions of the streams where the distance to bank was strongly and positively correlated with the years since root exposure in straight sections. In contrast, meandering bends also showed a positive but low correlation for root exposure date and distance collected. We attribute this difference to erosional processes (i.e., scour and mass wasting) occurring at these channel locations. When compared with other erosion studies across the southern U.S. prairie, our values were similar in magnitude but with low correlation to drainage area indicating site specificity of erosion mechanisms, and watershed landcover influence for different drainages, despite being in the same ecological region.

Impact of wastewater treatment upgrade and nitrogen removal on bacterial communities and their interactions in eutrophic prairie streams.

Eutrophication can impact bacteria by altering fluxes and processing of nutrients and organic matter. However, relatively little is known of how bacterial communities, diversity, and interactions with phytoplankton might respond to nutrient management. We used 16S rRNA amplicon sequencing to compare bacterial assemblages in the water column upstream (control) and downstream (impact) of a wastewater treatment plant (WWTP) located on a eutrophic prairie stream. Sampling occurred before (2012) and after (2018) the 2016 biological nutrient removal (BNR) upgrade that removed >90% of nitrogen (N, mainly NH4+). Multivariate ordination suggested that effluent-impacted bacterial communities were associated mainly with elevated NH4+ concentrations before the upgrade, whereas those after BNR were characteristic of reference systems (low NO3-, diverse regulation). Genera such as Betaproteobacteria and Rhodocyclacea were abundant at impacted sites in 2012, whereas Flavobacterium and a potential pathogen (Legionella) were common at impacted sites in 2018. Nitrifier bacteria (Nitrospira and Nitrosomonas) were present but rare at all sites in 2012, but recorded only downstream of the WWTP in 2018. Generalized additive models showed that BNR reduced bacterial diversity, with ∼70% of the deviance in diversity explained by hydrology, pH, nutrients, and phytoplankton abundance. Overall, NH4+ removal reduced symptoms of cultural eutrophication in microbe assemblages.

Intermittent Prairie Streams in the Northern Great Plains: A Case of an Undervalued Ecosystem

Small (<15 m wide), intermittent prairie streams in western South Dakota, a semiarid part of the northern United States, are undervalued ecosystems because they do not exemplify the values of classic, flowing streams. However, they are valuable as wildlife corridors, aquatic habitat for drought-adapted species, and support of local grazing economies. We surveyed 90 streams in 2018–2019, collecting data on geomorphic, water chemistry, and biological properties, focusing on vegetation and grazing impacts. We developed an approach for categorizing streams by landscape position and flow regime to facilitate appropriate land management and stream restoration actions. The result was a published landowner guide to provide information on low-tech riparian management and restoration options of the four stream types we categorized. The headwaters streams and woody draws with drainage areas <26 km2 are the most abundant types and exemplify the issues described above. Large rivers, despite drainage areas exceeding 260 km2 can go dry. Management issues include invasive plant species, lack of woody riparian establishment, poor water quality, overgrazing, channel incision, and water stress from climate change. The most cost-effective management practices involve rotational grazing and practices that reduce cattle impacts. More recently, beaver dam analogs have been installed and beaver reintroduction is being considered along with reestablishment of native bison herds in place of cattle. Intermittent prairie streams present an excellent case study of an undervalued ecosystem, illustrating the challenges and opportunities of such systems. Engagement of grazing landowners can improve stewardship of these systems.

The response of stream ecosystem properties to two size classes of herbivorous minnow species.

Losses in freshwater fish diversity might produce a loss in important ecological services provided by fishes in particular habitats. An important gap in our understanding of ecosystem services by fishes is the influence of individuals from different size classes, which is predicted based on known ontogenetic shifts in metabolic demand and diet. I used 20 experimental stream mesocosms located at Konza Prairie Biological Station (KPBS), KS, USA, to assess the influence of fish size on ecosystem properties. Mesocosms included two macrohabitats: one riffle upstream from one pool filled with consistent pebble and gravel substrate. There were four experimental and one control treatment, each replicated four times (N = 20). I used two size classes of central stonerollers (Campostoma anomalum) and southern redbelly dace (Chrosomus erythrogaster). Five ecosystem properties were assessed: algal filament length (cm), benthic chlorophyll a (μg/cm2), benthic organic matter (g/m2), macroinvertebrate biomass (g/m2), and stream metabolism (g O2/m2/day-1). Size structure of fish populations affected some, but not all, ecosystem properties, and these effects were dependent upon species identity. Size structure of both species had effects on algal filament lengths where stonerollers of both size classes reduced algal filaments, but only small redbelly dace kept filaments short. A better understanding of the relationship between these prairie stream minnows and their small stream habitats could be useful to both predict changes in stream properties if species are lost (redbelly dace are a Species In Need of Conservation) or size structure shifts.

Indirect functional effects of neighbors on food web compartments could not overcome density-dependent limited growth of a grazing minnow

Ecosystems include diverse taxonomic and functional groups of animals with variable levels of niche overlap that can lead to direct and indirect interactions with positive or negative outcomes. Species feeding at low trophic positions might be sensitive to interactions with co-occurring functional groups (neighbors) that influence their food resources through various processes, such as indirect nutrient subsidies and trophic cascades. Employing a target-neighbor experimental design using large, outdoor mesocosms, we tested whether adding neighbors with different functional traits affected food web compartments relative to a control group that had grazing minnows, Campostoma anomalum (Central Stoneroller). Additionally, we tested whether growth and body condition of Central Stoneroller was positively influenced through interactions with each neighbor treatment: additional stonerollers, benthic-insectivorous fish Etheostoma spectabile (Orangethroat Darter), terrestrial insectivorous fish Lepomis megalotis (Longear Sunfish), or filter-feeding mussels (two-species assemblage) that are predicted to increase primary production through nutrient enrichment, a trophic cascade or both. Over the 29-day experiment, the presence of neighbors had generally negative or highly variable effects on food web compartments. Stoneroller growth was not evident during the experiment and body condition generally declined but was not influenced by neighbor treatments. Our results show that adding neighboring functional group did not reduce density-dependent growth of grazing fishes via indirect food web interactions over short temporal scales. This study suggested that indirect interactions among species and their combined influence on ecosystem properties were weak under experimental conditions representing typical prairie stream communities.

A perched culvert and natural obstructions limit fish dispersal in an intermittent prairie stream

Poorly constructed road crossings block upstream movement of fish into stream reaches that provide critical habitat or connect isolated populations. Although removing these barriers is often a conservation priority, quantifying fish passage following removal has not been well studied, particularly in intermittent streams. In this study, we sought to understand how barriers influence the dispersal of fishes in intermittent prairie streams. We used passive integrated transponder tags and antenna stations to quantify fish movement of 3 prairie-stream fishes (Central Stoneroller Campostoma anomalum [Rafinesque, 1820], Southern Redbelly Dace Chrosomus erythrogaster [Rafinesque, 1820], and Creek Chub Semotilis atromaculatus [Mitchill, 1818]) through a road crossing in an intermittent prairie stream for 3 y before and 3 y after removing a perched culvert. We verified that no upstream fish movement occurred through the culvert, despite large aggregations of tagged fish in the intermittent reach below the culvert. In contrast, tagged individuals of all 3 species were detected above the road crossing in each of the 3 y following removal. We also tracked the recovery of these species, plus the Orangethroat Darter Etheostoma spectabile (Agassiz, 1854), following a severe drought in 2018 in 2 spring-fed tributary reaches, 1 without a downstream barrier and 1 with the removed downstream culvert. Surveys of the tributary reaches showed rapid recovery of fish densities following drought in the tributary without a downstream barrier. However, recovery at the site above the removed culvert appeared to be limited by a natural waterfall. Our observations suggest barrier removal allowed access to spawning habitat within the intermittent reach immediately upstream of the site, but other obstacles or shear distance to perennial spring-fed tributary reaches also limited recolonization following severe drought. Increased connectivity between perennial and intermittent reaches in prairie streams likely benefits fishes by increasing their resilience following disturbance and providing habitat during critical life stages.

Ecological integrity assessment of streams in the light of natural ecoregions and anthropic land use.

Reference conditions for river bioassessment should be established inside ecoregions. Our objectives were (1) to implement a bioassessment methodology for Uruguayan prairie streams regarding ecoregions and land use and (2) to assess the ecological integrity of streams of the Río Negro basin in Uruguay. Due to logistical constraints, sampling was divided into two collection trips: one including the upper basin in fall 2015 and the other including the lower basin in spring 2016. Basins were analyzed separately due to seasonal and geographical differences. In the streams sampled in fall 2015, conductivity, total nitrogen (TN), and total phosphorus (TP) were higher in sedimentary ecoregions than in crystalline ones, independent on land use. In those sampled in spring 2016, these variables showed the highest values in the ecoregions dominated by agriculture. Eighty percent of the sampled streams presented the impact of cattle in their riparian zone. Discriminant analysis showed a similar composition of macroinvertebrates among ecoregions in 2015, but different composition between land uses. Conversely, in 2016, there were differences among some ecoregions, but not between land uses. Agriculture was correlated with tolerant invertebrates, while natural land use and afforestation were correlated with sensitive ones. The BMWP-Colombia showed the impact of livestock on streams, but in general good water quality, while an index of genera for Uruguay, indicated that all streams are eutrophic, thereby confirming the importance of using different types of metrics. Due to its geographical homogeneity and small size, a smaller number of ecoregions could be defined for stream assessments in the Río Negro basin.

Prairie stream metabolism recovery varies based on antecedent hydrology across a stream network after a bank‐full flood

ABSTRACTIntermittent streams are characterized by significant periods of low to no flow, yet are also frequently subjected to flashy, high floods. Floods alter ecosystem function and result in variable successional patterns across the stream network. Yet, the timing of restored function after floods in intermittent stream networks is relatively unexplored. We measured recovery of stream ecosystem function using rates of gross primary production (GPP), ecosystem respiration (ER), net ecosystem production (NEP), and the primary production to respiration ratio (P/R) across eight locations in the Kings Creek drainage basin with differing preflood conditions (previously dry [intermittent] or flowing [perennial]) over a 30‐d period following a 2‐yr return interval flood. We found that all metabolic rates (GPP, ER, NEP, P/R) varied primarily by time (days since flood) and antecedent flow, but not spatial network position (i.e., drainage area). Intermittent sites exhibited high rates of ER (0.17–3.33 g dissolved oxygen [DO] m−2 d−1) following rewetting compared to perennial sites (0.03–1.17 g DO m−2 d−1), while GPP, NEP, and P/R were slower to recover and varied less between sites of differing preflood conditions. Metabolic rates were not strongly influenced by other environmental conditions. A large proportion of variation was explained by the random effect of location. Our results suggest that metabolism is temporally asynchronous and highly heterogenous across intermittent watersheds and that antecedent hydrology (drying prior to rewetting) stimulates heterotrophic activity, likely dependent on terrestrially derived organic matter and nutrient subsidies.

Upland Rootzone Soil Water Deficit Regulates Streamflow in a Catchment Dominated by North American Tallgrass Prairie

Intermittent tallgrass prairie streams depend on surface runoff and are highly susceptible to hydrological disturbances such as droughts. The objective of this study was to investigate the timing of intermittent streamflow pulses and upstream rootzone soil water deficit in a watershed dominated by tallgrass prairie. The study was conducted from July to December 2021 in the Kings Creek watershed located within the Konza Prairie Biological station, Kansas, USA. Hourly precipitation and soil moisture observations in the 0–10, 10–30, and 30–50 cm depth were obtained from a hydrological network consisting of 16 monitoring stations across the Kings Creek watershed. Rootzone soil water storage (S) was computed at hourly time steps as the sum of the soil water storage of each soil layer. A drained upper limit (DUL) was estimated as the soil moisture remaining 24 h after the soil had been thoroughly wetted during large (~100 mm) rainfall events. A lower limit (LL) was estimated as the lowest rootzone soil water storage during the study period. Hourly soil water deficit (D) was computed as D = (DUL − S)/(DUL − LL). The study period had 19 precipitation events totaling 436 mm, and only 14 out of the 19 precipitation events exceeded a common canopy and litter interception threshold of 4 mm for tallgrass prairies in this region. Only two precipitation events resulted in measurable streamflow, and the inception of these two streamflow events was associated with a negative weighted soil water deficit (i.e., S > DUL). This pilot study revealed that upland rootzone soil water deficit plays a major role controlling the timing of streamflow in the Kings Creek watershed and possibly in other catchment areas with intermittent prairie streams.

AGE-SPECIFIC PATTERNS OF OCCURRENCE, DENSITY, AND GROWTH OF TWO CYPRINID FISHES IN HEADWATER PRAIRIE STREAMS

Ontogenetic changes in the ecological requirements of fishes are thought to influence intraspecific patterns of occurrence and abundance, yet patterns of variation in the distribution of different cohorts are unknown for many species. In prairie stream headwaters with variable habitats, we predict cohort occurrences, densities, and juvenile growth rates to vary considerably over both space and time. Specifically, the differences in abiotic factors across sites will likely affect the occurrence and growth of different age classes. To evaluate factors associated with cohort structure, we evaluated population dynamics of two cyprinid species, central stoneroller Campostoma anomalum and southern redbelly dace Chrosomus erythrogaster, using a long-term monitoring data set that included six sites sampled semiannually for 8 to 14 years. Densities of adult stoneroller were higher in pools while juveniles had higher densities in riffles, leading to within-site spatial differences in the occurrence of each age class. Across-site habitats also varied in the occurrence of different age classes of stonerollers, with sites being either suitable for both adults and juveniles, specialized for one age class, or temporally variable for both age classes. In contrast to stonerollers, all age classes of dace were pool specialists with constantly high occurrences of both age classes during all times of the year. Age-specific growth, for both species, did not vary across sites, but growth was higher for stonerollers during wet years compared with drier years at two sites. Headwater streams provide important habitat for many fishes, but the use of age-specific habitats is variable among species and likely driven by species traits as well as biotic and abiotic characteristics of those habitats.

Combined effects of urbanization and longitudinal disruptions in riparian and in-stream habitat on water quality of a prairie stream

Local habitat and riparian modifications imposed by surrounding land use drastically impact the water quality of streams. However, whether these effects could still be discernible when the watercourse also receives urbanization effluents has not been fully explored. We evaluated the water quality of a Neotropical prairie stream exposed to urbanization and explored the role of downstream patches of different surrounding land uses (cropland and livestock) in further regulating water quality. Forty-two variables of water quality, habitat structure and riparian condition were measured at four reaches of the Langueyú stream. Significant differences in water quality were observed. Water conductivity, dissolved oxygen, salinity, dissolved solids, chloride, inorganic nitrogen and bacteriological loads displayed a continuum of recovery from the urban reach. Indeed, almost 24 percent of the total variation in water quality was explained by the longitudinal arrangement of sites. Alternatively, pH, phosphorous, suspended solids and chemical oxygen demand showed a disruption in this continuum of recovery and were highly related with local aspects of habitat structure and riparian conditions imposed by cropland and livestock. Key aspects of effluent treatment, riparian integrity and in-stream habitat must be addressed within a comprehensive social context in order to design sustainable management of fluvial urbanised ecosystems.

Spatial and temporal patterns of urea content in a eutrophic stream continuum on the Northern Great Plains

Urea can degrade water quality and stimulate toxic phytoplankton in P-rich lakes, yet little is known of its sources, abundance, or transportation in lotic systems, particularly within the Northern Great Plains. We measured physico-chemical parameters biweekly during May–September 2010–2012 at 16 stations along a 250 km lotic continuum to quantify spatial and temporal variation in urea concentrations and discharge, and to identify potential regulatory processes. Urea concentrations were similar to those in regional prairie lakes (range 5.2–792.1, median 78.6 μg N L−1) with variable seasonal mean (± SD) concentrations (96.6 ± 96.1 μg N L−1) and fluxes (4.22 × 105 ± 257.6 μg N s−1). Landscape analysis with generalized additive models explained 68.3% of deviance in urea concentrations, with high temporal variability predicted mainly by positive relationships with nutrient content and chlorophyte abundance, but not temperature, dissolved organic matter, bacterial abundance, or urban effluent. Seasonal analysis revealed that during spring, urea content was correlated negatively with leguminous forage cover (% area) and positively with stream discharge, oilseed and cereal crops, and shrubs or deciduous plants, while during summer, urea concentrations were correlated negatively with discharge and leguminous crop cover, as well as nutrient levels. Mean porewater urea concentrations (528.5 ± 229.8 μg N L−1) were over five-fold greater than stream concentrations, suggesting that hyporheic production may offset declining influx from terrestrial sources during summer. We conclude that urea may be ubiquitous in eutrophic prairie streams and that management of its export from land may reduce detrimental effects on downstream lakes.

Effects of nitrogen removal from wastewater on phytoplankton in eutrophic prairie streams

AbstractBiological nutrient removal (BNR) may be an effective strategy to reduce eutrophication; however, concerns remain about effects on receiving waters of removing both nitrogen (N) and phosphorus (P), rather than P alone.Phytoplankton abundance (as µg chlorophyll a/L) and community composition (as nmol biomarker pigment/L) were quantified over 6 years in two connected eutrophic streams to determine how algae and cyanobacteria varied in response to a shift from tertiary (P removal) to BNR (N and P removal) wastewater treatment.Phytoplankton were sampled biweekly at nine stations May to September and were analysed using generalised additive models (GAMs) to quantify landscape patterns of phototrophs and identify potential causal relationships both before (2010–2012) and after (2017–2019) BNR installation in 2016.Analysis with GAMs showed that 69%–79% of deviance in phytoplankton abundance and composition could be explained by date‐ and site‐specific variance in stream flow, temperature, and solute concentrations (mainly nutrients), whereas similar GAMs using only effluent N content (δ15Nwater) as a predictor explainedc. 60% of phototroph deviance. Prior to BNR, phytoplankton levels (mainly chlorophytes) increased with‐rich effluent, whereas their abundance declined with δ15N after BNR (diatoms, chlorophytes).Overall, declines in total effluent release of N (67%–97%) but not P (c. 0%) due to BNR resulted in a 52 ± 7% decline in phytoplankton abundance relative to upstream values, despite high inter‐annual variation in discharge and baseline chlorophyll a concentration.Nitrogen removal by BNR improved water quality in N‐limited ecosystems.

Fish assemblage structure in a Neotropical urbanised prairie stream exposed to multiple natural and anthropic factors

AbstractA myriad of factors affect stream fish assemblages, and most of them are intimately regulated by surrounding land uses. One of the most pernicious impacts on streams is the release of urban effluents. Accordingly, understanding the fish assemblage patterns as well as the environmental drivers that modulate them in the context of urban streams which also are exposed to other land uses is mandatory. We evaluated the longitudinal patterns of fish assemblages in an urbanised Neotropical prairie stream exposed to downstream patches of different surrounding land uses. Several variables of water quality, in‐stream habitat and riparian corridors were measured, and their relationships with fish metrics were explored. A fish metric selection protocol was implemented, and several multivariate analyses were used. Three main patterns of fish response were observed. Assemblage‐level attributes as diversity, richness, biomass, number of families and trophic guilds and proportion of Characiformes and intolerant species were responsive to the natural gradient in habitat (pools) and riparian (riparian width) conditions expected in non‐impacted lotic ecosystems. Conversely, a downstream continuum of recovery in water quality (dissolved oxygen, conductivity, NO3:NH4 and bacteriological loads) and habitat structure (sediment depth) would influence the distribution of fish species regarding their environmental tolerance and habitat preferences. Finally, local habitat aspects (nitrites, submerged macrophytes, bare soil cover and bank incisions by livestock) seemed relevant for the trophic structure (omnivorous species) of fish assemblages. A complex natural and anthropic longitudinal scenario together with local disruptions imposed by surrounding land uses were directive for fish.

Assessing Linkages Between Small Impoundments and Long-term Trajectories of Prairie Stream Fish Assemblages

Most stream fish communities have changed over time in response to common anthropogenic disturbances. Impoundments are a widespread anthropogenic stressor that can negatively impact stream fishes as they alter flow regimes, block movements, and act as fountainheads for the introduction and spread of invasive species. Recent studies, however, have reported the occurrence and reproduction of native fishes in impoundments, suggesting they might benefit some native fishes. Our primary objective was to evaluate whether impoundment construction has led to changes in fish community structure in prairie streams. To accomplish this, we compared fish occupancy in small impoundments (,5 ha) to temporal trends in stream occupancy among species to test whether species' increases in stream occupancy were related to their occupancy in impoundments. We examined stream fish communities in the Upper Cottonwood River basin, Kansas, from 1948–2018, and sampled small impoundments in 2016 and 2017. A third (32%) of fish communities in impoundments were similar to stream assemblages, whereas most impoundments (68%) were dominated by sport or bait fishes. In streams, six species showed increases in occupancy and four species showed decreases since small impoundment construction. Of the species that exhibited increased stream occupancy, five showed a positive, logistical relationship between a species' impoundment occupancy and its increase in stream occupancy. Species declining in stream occupancy experienced continued linear declines and may still be declining. Our research suggests stream fish communities have changed since impoundment construction, and are associated with locally-invasive, native species reaching a new stable state in streams accompanied by declines in other native stream fish species.

Trophic ecology of the Neotropical tolerant fish Corydoras paleatus under the influence of contrasting environmental conditions in a prairie stream.

Worldwide, land use changes and urbanization affect habitat and biota in streams, drastically disrupting environmental conditions and biotic interactions. We evaluated the trophic ecology of the tolerant fish Corydoras paleatus in a prairie stream with contrasting environmental conditions intimately aligned with different nearby land uses. Gut analyses was conducted at three stream reaches with contrasting ecological attributes regarding water quality, habitat structure and riparian condition. A total of 231 guts were analyzed and 15 prey items identified. A significant variation in composition and structure of the dietary assemblage, niche breadth and feeding patterns of C. paleatus under different environmental conditions was observed. Psychodidae prevailed in most deteriorated environmental conditions and Chironomidae, followed by nematodes, in stream reaches where environmental conditions improved. Maximum niche breadth and a larger proportion of generalist individuals were found at the most deteriorated site. Conversely, the proportions of specialized individuals were slightly higher at sites with better ecological conditions. Psychodidae and mineral fragments were positively correlated with the most detrimental conditions, while filamentous algae prevailed where these conditions improved. Overall, good evidence suggesting that trophic ecology of a tolerant species is affected by local environmental conditions in water quality, habitat structure and riparian corridor was observed.

Reproduction and Age Structure of the Plains Killifish Fundulus zebrinus from Two Tributaries of the Upper Red River, Texas

Plains Killifish Fundulus zebrinus (subgenus Plancterus) is native to river basins in Oklahoma, New Mexico, and Texas. Original descriptions of Plains Killifish life history information are now applicable to the sister taxon Northern Plains Killifish Fundulus kansae following recognition of the 2 species in 2001. Study objectives were to quantify (1) length of the reproductive season, using the gonadosomatic index and categories of gonadal maturation, (2) batch fecundity, and (3) number of age groups for Plains Killifish taken from 2 rivers within the upper Red River basin of Texas. Reproductive season was from March through September, with the production of multiple batches and a maximum batch of 131 mature oocytes. Plains Killifish were sexually mature at age 1 and had an estimated life span of 2–3 years. Reproductive season, production of multiple batches, and age of Plains Killifish were similar to those reported for Northern Plains Killifish and 2 other closely related subgenera, Wileyichthys and Zygonectes. These similarities suggest strong trait conservatism among a monophyletic group of fundulids that inhabit a diversity of freshwater and saltwater environments in western shallow bays and salt marshes, southwestern arid and prairie streams, and eastern low-gradient streams of North America.