Reliability Estimates for Ivlev's Electivity Index, the Forage Ratio, and a Proposed Linear Index of Food Selection

Strauss, Richard E.

doi:10.1577/1548-8659(1979)108<344:refiei>2.0.co;2

Cited by 453 publications

(286 citation statements)

References 17 publications

Supporting

Mentioning

277

Contrasting

Unclassified

Order By: Relevance

“…Results were summed by macrohabitat type, and the percentage of all available habitats was calculated for each macrohabitat. Strauss's (1979) linear selectivity index (L i ) was chosen to examine habitat selection by pallid sturgeon because it is not as susceptible to sampling bias when the habitat type represents a small or minute proportion of all available habitats (Lechowicz 1982). A chisquare goodness-of-fit test was used to determine whether significant selection was occurring.…”

Section: Methodsmentioning

confidence: 99%

Habitat Use by Middle Mississippi River Pallid Sturgeon

et al. 2004

View full text Add to dashboard Cite

Little is known about the habitat preferences and needs of pallid sturgeon Scaphirhynchus albus, which was federally listed as endangered in 1990. To learn more about habitat use and selection by pallid sturgeon, sonic transmitters were surgically implanted in 27 individuals from the middle Mississippi River. Study fish were located 184 times (1–23 times/individual) from November 1995 to December 1999. Of the seven macrohabitats identified, pallid sturgeon were found most often in main‐channel habitats (39% of all relocations) and main‐channel border habitats (26%); the between‐wing‐dam habitats were used less often (14%). Strauss's linear selectivity index (Li) values indicated that study fish exhibited positive selection for the main‐channel border, downstream island tips, between‐wing‐dam, and wing‐dam‐tip habitats; they showed negative selection for main‐channel, downstream of wing dams, and upstream of wing dam habitats. Comparison of Li values for four temperature ranges and three daily mean discharge ranges revealed little change in habitat selection due to temperature or discharge. Habitat use patterns also were similar across seasons and discharge regimes, except during spring months when between‐wing‐dam habitats saw greater use and main‐channel and main‐channel border habitat use declined. These changes may have been a response to high river stages associated with spring flooding, which may create favorable feeding areas in the between‐wing‐dam habitats. Enhancement and restoration of habitat diversity, particularly downstream island tip and between‐wing‐dam habitats, may be necessary for the recovery of pallid sturgeon in the middle Mississippi River.

show abstract

Section: Methodsmentioning

confidence: 99%

Habitat Use by Middle Mississippi River Pallid Sturgeon

et al. 2004

View full text Add to dashboard Cite

show abstract

“…v www.esajournals.org methods described in the experiment. To assess whether coho in the experiment and field preferred certain prey items, diet selectivity was determined as L ¼ r i À p i , where r i and p i are the proportions by biomass of prey type i in the diet and drift, respectively (Strauss 1979). When calculating selectivity in channels, we used drift biomass rather than abundance.…”

Section: Field Studymentioning

confidence: 99%

Linking resource availability and habitat structure to stream organisms: an experimental and observational assessment

et al. 2014

View full text Add to dashboard Cite

An experiment and a mark‐recapture field study of juvenile coho salmon (Oncorhynchus kisutch) were conducted to identify controls of key energy flow chains in river food webs. In the small‐scale experiment, we investigated the individual and interactive effects of physical habitat structure (PHS) as small wood and resource availability (tissue of adult Chinook salmon, O. tshawytscha) on nutrients, algae, invertebrates, and fish predators including juvenile coho. In the field, we quantified the effects of natural variation in prey availability (invertebrate drift biomass), PHS (wood), and local fish density on summer growth of juvenile coho across multiple stream reaches. Adding salmon tissue to experimental channels resulted in strong bottom‐up effects on select invertebrates including increased population biomass of chironomids and baetids, the numerically dominant invertebrates, and faster growth of juvenile coho. We link the enhanced growth of coho to chironomid productivity: for instance, adult chironomid flux was 4.3× higher and coho consumption of these animals 3× higher in salmon‐subsidized channels. PHS in experimental channels was associated with reduced algal biomass, potentially in response to increased invertebrate consumption, and invertebrate flux or export. The field study revealed coho growth was negatively related to PHS and total fish density and positively related to Diptera drift biomass; however, the effects of fish density and drift biomass on coho growth were relatively weak. The field study also indicated that prey resource availability and coho growth were associated with differences in canopy cover, with prey biomass and coho growth 2–4× higher in reaches receiving more sunlight. As in the experiment, coho in natural stream reaches predominantly fed on adult chironomids and other Diptera, indicating that these taxa and life‐stages are a key link between the benthic food web and mobile vertebrate predators. Our study showed that bottom‐up processes initiated by salmon subsidies and possibly light flux determined key trophic interactions in the Cedar River food web. Moreover, we speculate that PHS may modify some of these interactions indirectly through its effects on the movement of organisms through the environment.

show abstract

“…The relative levels of the various food items (i) found in the bladderworts are expressed both in terms of frequency of occurrence (FOi: number of traps with the item i versus the total number of traps containing at least one prey) and relative abundance (RAi: number of prey i versus the total number of captured prey). Preferences in the diets of U1 and U2 were evaluated using the Liner Food Selection Index (L) (Strauss, 1979). L was calculated for the principal prey as L=ri-pi, where ri is the RA of prey item i in the bladder and pi is the RA of the same prey item i among the overall zooplankton community.…”

Section: Study and Preparation Of Trap Samplesmentioning

confidence: 99%