Geology topics
Charles F. Rabeni
Publications and source records attributed to Charles F. Rabeni.
Home range and space use patterns of flathead catfish during the summer-fall period in two Missouri streams
Flathead catfish Pylodictis olivaris were radio-tracked in the Grand River and Cuivre River, Missouri, from late July until they moved to overwintering habitats in late October. Fish moved within a definable area, and although occasional long-distance movements occurred, the fish typically returned to the previously occupied area. Seasonal home range was calculated with the use of kernel density estimation, which can be interpreted as a probabilistic utilization distribution that documents the internal structure of the estimate by delineating portions of the range that was used a specified percentage of the time. A traditional linear range also was reported. Most flathead catfish (89%) had one 50% kernel-estimated core area, whereas 11% of the fish split their time between two core areas. Core areas were typically in the middle of the 90% kernel-estimated home range (58%), although several had core areas in upstream (26%) and downstream (16%) portions of the home range. Home-range size did not differ based on river, sex, or size and was highly variable among individuals. The median 95% kernel estimate was 1,085 m (range, 70– 69,090 m) for all fish. The median 50% kernel-estimated core area was 135 m (10–2,260 m). The median linear range was 3,510 m (150–50,400 m). Fish pairs with core areas in the same and neighboring pools had static joint space use values of up to 49% (area of intersection index), indicating substantial overlap and use of the same area. However, all fish pairs had low dynamic joint space use values (<0.07; coefficient of association), indicating that fish pairs were temporally segregated, rarely occurring in the same location at the same time.
The importance of fluvial hydraulics to fish-habitat restoration in low-gradient alluvial streams
1. A major cause of degradation and loss of stream fish is alteration of physical habitat within and adjacent to the channel. We describe a potentially efficient approach to fish restoration based upon the relationship between fluvial hydraulics, geomorphology, and those habitats important to fish. 2. The aquatic habitat in a low-gradient, alluvial stream in the Ozark Plateaus physiographical province was classified according to location in the channel, patterns of water flow, and structures that control flow. The resulting habitat types were ranked in terms of their temporal stability and ability to be manipulated. 3. Delineation and quantification of discrete physical spaces in a stream, termed hydraulic habitat units, are shown to be useful in stream restoration programmes if the ecological importance of each habitat unit is known, and if habitats are defined by fluvial dynamics so that restoration is aided by natural forces. 4. Examples, using different taxa, are given to illustrate management options.
Demographics and chronology of a spawning aggregation of blue sucker ( Cycleptus elongatus ) in the Grand River, Missouri, USA
The blue sucker ( Cycleptus elongatus ) was sampled as individuals arrived, spawned, and departed from a spawning rime in the Grand River of northcentral Missouri, USA. The Grand River basin was not known to support blue sucker reproduction with few individuals ever recorded. The spawning site is unique in character for the lower river. Individuals began arriving in early April when water temperatures reached 10–12°C. Females with freely-flowing roe were sampled in late April after a large rise in river stage and concurrent lowering of the water temperature 4–5 degrees to 16.5°C. The spawning aggregation had a mean age of 15 y and ranged from 9 to 22 y based on scales that probably underestimated true ages. Males outnumbered females 5.5:1. Mean length was 659 mm for males and 721 mm for females. Females were longer at age than males and no significant age-length relationship was evident.
Recovery of prairie fish assemblages at the transition from channelized to nonchannelized: Implications for conservation of natural channels
Fish assemblages were systematically sampled along the transition from channelized to unchannelized reaches in seven streams in northern Missouri, USA. Streams ranged in size from 4th to 8th order and were located in the Central Dissected Till Plains including the Grand, Chariton, Salt, and Fabius watersheds. Maximum species richness was reached 3-5 km downstream from the end of channelization. A limited core group of 10 species was present at most of the sites (channelized and unchannelized locations), and a diverse group of 45 species was present at relatively few sites (rarely channelized locations). The core group consisted largely of tolerant, omnivorous species and contained no top carnivores. The 45-species diverse group included a greater proportion of intolerant, benthic invertivorous, lithophilous, and carnivorous species. The effect of channelization extended well into unchannelized reaches and should be considered by conservation planners.
Natural thermal refugia for temperate warmwater stream fishes
The seasonal use of an Ozark spring branch by fishes was evaluated from January 1993 to January 1995. Temperatures in the spring branch were fairly constant, at 13.5 ± 1°C, and usually exceeded the temperature of a receiving stream during the November–March coldwater period. Black redhorse Moxostoma duquesnei , smallmouth bass Micropterus dolomieu , shadow bass Ambloplites ariommus , and longear sunfish Lepomis megalotis showed a temporal pattern of use in the spring branch. The lowest use was during the April–October warmwater period, and the greatest use was during the coldwater period. During cold periods, biomass of these four species in the spring branch was significantly greater and fish size significantly larger than in similar habitats in the adjoining stream. The weight per unit length of fish using the spring branch during cold periods was also significantly greater. Shadow bass and longear sunfish had significantly greater relative stomach contents than conspecifics in equivalent habitats from the adjoining stream, but had similar relative numbers of eggs. Large concentrations of adult fish used spring branches during the coldwater period, and these fish may be more vulnerable to angling than conspecifics in similar habitats in adjoining streams dominated by surface water. Thus, we suggest that stream managers consider the usefulness of fish refuges in spring branches and adjacent thermally influenced areas.
Climate response among growth increments of fish and trees
Significant correlations were found among the annual growth increments of stream fish, trees, and climate variables in the Ozark region of the United States. The variation in annual growth increments of rock bass ( Ambloplites rupestris ) from the Jacks Fork River was significantly correlated over 22 years with the ring width of four tree species: white oak ( Quercus alba ), post oak ( Quercus stellata ), shortleaf pine ( Pinus echinata ) and eastern red cedar ( Juniperus virginiana ). Rock bass growth and tree growth were both significantly correlated with July rainfall and stream discharge. Variations in annual growth of smallmouth bass ( Micropterus dolomieu ) from four streams were significantly correlated over 29 years (1939–1968) with mean May maximum air temperature but not with tree growth. The magnitude and significance of correlations among growth increments from fish and trees imply that conditions such as topography, stream gradient, organism age, and the distribution of a population relative to its geographic range can influence the climatic response of an organism. The timing and intensity of climatic variables may produce different responses among closely related species.
Sensitivity of early-life stage golden trout to low pH and elevated aluminum
Early-life-stage golden trout ( Oncorhynchus aguabonita aguabonita ) were exposed to acid and Al to examine the response and determine the sensitivity of a western, alpine salmonid to conditions simulating an episodic pH depression. Freshly fertilized eggs, alevins, and swim-up larvae were exposed for 7 d to one of 12 combinations of pH and Al, and surviving fish were held to 40 d post-hatch to determine the effect of exposure on subsequent survival and recovery. Golden trout are sensitive to conditions simulating episodic acidification events typically observed in the field. Significant mortality occurred when the pH of test waters was below 5.0 in the absence of Al or when pH was 5.5 in the presence of 100 μg/L total Al. Behavioral impairments were sensitive indicators of low pH and Al stress. Impaired locomotory and feeding behavior occurred at pH 5.5 without Al and at Al concentrations > 50 μg/L. In contrast, growth, RNA-to-DNA ratio, and whole-body ion concentration were relatively less sensitive indicators of sublethal acid and Al stress.
Biomonitors of stream quality on agricultural areas: fish versus invertebrates
Although the utility of using either fish or benthic invertebrates as biomonitors of stream quality has been clearly shown, there is little comparative information on the usefulness of the groups in any particular situation. We compared fish to invertebrate assemblages in their ability to reflect habitat quality of sediment-impacted streams in agricultural regions of northeast Missouri, USA. Habitat quality was measured by a combination of substrate composition, riparian type, buffer strip width, and land use. Invertebrates were more sensitive to habitat differences when structural measurements, species diversity and ordination, were used. Incorporating ecological measurements, by using the Index of Biological Integrity, increased the information obtained from the fish assemblage. The differential response of the two groups was attributed to the more direct impact of sediments on invertebrate life requisites; the impact of sedimentation on fish is considered more indirect and complex, affecting feeding and reproductive mechanisms.