Diet Niche Width and Individual Specialization of Brook Trout in Adirondack Lakes

2017 ◽  
Vol 146 (4) ◽  
pp. 716-731 ◽  
Author(s):  
Kurt J. Jirka ◽  
Clifford E. Kraft
Keyword(s):  
Brook Trout ◽  
Niche Width ◽  
Individual Specialization ◽  
Adirondack Lakes

Differences in sexual maturity and fall emigration between diploid and triploid brook trout (Salvelinus fontinalis) in an Adirondack lake

1997 ◽  
Vol 54 (8) ◽  
pp. 1808-1812 ◽  
Author(s):  
J A Warrillow ◽  
D C Josephson ◽  
W D Youngs ◽  
C C Krueger
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Gonadal Development ◽  
Spawning Habitat ◽  
Diploid Males ◽  
Reproductive Risk ◽  
Spawning Areas ◽  
In Captivity ◽  
Adirondack Lakes ◽  
Triploid Fish

High levels of emigration coincident with maturity and spawning have been reported from brook trout (Salvelinus fontinalis) populations in Adirondack lakes. These lakes typically had few spawning areas and required stocking to maintain populations. We compared diploid and triploid brook trout to identify differences in gonadal development and emigration. Age 1 + and 2 + diploid and triploid brook trout held in captivity were examined internally for gonadal development. More diploid trout were mature than triploid fish (p < 0.01). Of triploid brook trout that matured, all were males. Yearling diploid and triploid brook trout were also stocked into a lake that had an outlet but no spawning areas. During the fall spawning season, only mature yearling triploid males, diploid males, and diploid females were caught in an outlet trap. No triploid females were caught. A greater proportion of diploids emigrated than triploids (p < 0.01). Triploidy in females arrested emigration by preventing sexual maturation. Triploid male brook trout should not be stocked because they can pose a reproductive risk to wild brook trout downstream from lakes. Stocking triploid females could reducefall emigration and thus reduce the loss of catchable brook trout from Adirondack lakes with outlets and little spawning habitat.

Selection of Factors Affecting the Presence of Brook Trout (Salvelinus fontinalis) in Adirondack Lakes: A Case Study

1992 ◽  
Vol 49 (3) ◽  
pp. 597-608 ◽  
Author(s):  
J. J. Beauchamp ◽  
S. W. Christensen ◽  
E. P. Smith
Keyword(s):  
Logistic Regression ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Model Development ◽  
Predictive Ability ◽  
Absolute Magnitude ◽  
Regression Diagnostics ◽  
Data Set ◽  
Factors Affecting ◽  
Adirondack Lakes

We used multiple logistic regression techniques to develop models for estimating the probability of brook trout (Salvelinus fontinalis) presence/absence as a function of observable water chemistry variables and watershed characteristics. The data set consists of the Adirondack Lakes Survey Corporation data collected on 1469 lakes during 1984–87. Two models fitted to a randomly selected development subset of lakes, using two sets of candidate explanatory/predictor variables of particular interest, were compared on the basis of coefficient consistency and predictive ability. In addition to the usual maximum likelihood logistic regression results, we also applied collinearity and other associated diagnostics and variable-selection procedures designed specifically for the logistic regression model to arrive at parsimonious models. Both models correctly predicted fish presence in more than 85% of the model development set and more than 80% of the lakes in the verification data. For those variables appearing in both models, the signs of the estimated coefficients were the same and in agreement with expectation. The removal of influential observations, as indicated by the logistic regression diagnostics, caused all of the estimated coefficients to increase in absolute magnitude. This results in a model which is more sensitive to changes in the explanatory variables.

scholarly journals Isotopic Niche Partitioning and Individual Specialization in an Arctic Raptor Guild

2021 ◽  
Author(s):  
Devin L. Johnson ◽  
Michael T. Henderson ◽  
David L. Anderson ◽  
Travis L. Booms ◽  
Cory T. Williams
Keyword(s):  
Resource Availability ◽  
Niche Overlap ◽  
Niche Width ◽  
Foraging Strategies ◽  
Foraging Efficiency ◽  
Isotopic Niche ◽  
Individual Specialization ◽  
Niche Specialization ◽  
Niche Variation ◽  
Golden Eagles

Abstract Intra- and inter-specific resource partitioning within predator communities is a fundamental component of trophic ecology, and one proposed mechanism for how populations partition resources is through individual niche variation. The Niche Variation Hypothesis (NVH) predicts that interindividual trait variation leads to functional trade-offs in foraging efficiency, resulting in populations comprised of individual dietary specialists. A modified version of the NVH [mNVH] predicts niche specialization is plastic and responsive to fluctuating resource availability. We quantified niche overlap and tested the mNVH within an Arctic raptor guild, focusing on three species that employ different foraging strategies: Golden Eagles (generalists); Gyrfalcons (facultative specialists); and Rough-legged Hawks (specialists). Tundra ecosystems exhibit cyclic populations of arvicoline rodents (lemmings and voles), providing a unique system under which to examine interannual fluctuations in predator resource availability. Using blood δ13C & δ15N values from 189 raptor nestlings on Alaska’s Seward Peninsula (2014–2019), we calculated isotopic niche width and used Bayesian stable isotope mixing models (BSIMMs) to characterize individual specialization and test the mNVH. We observed a high degree of isotopic niche overlap between the three species and variable trophic responses to different stages of the arvicoline rodent cycle. Elevated arvicoline rodent abundance corresponded to reduced niche overlap among species and increased individual specialization in Golden Eagles and Gyrfalcons. Further, Gyrfalcons displayed a positive relationship between individual specialization and population niche width on an interannual basis consistent with the mNVH. Our findings suggest plasticity in niche specialization may reduce intra- and inter-specific resource competition under dynamic ecological conditions.

Does prey mobility affect niche width and individual specialization in hunting wasps? A network-based analysis

Oikos ◽  
2012 ◽  
Vol 122 (3) ◽  
pp. 385-394 ◽  
Author(s):  
Carlo Polidori ◽  
Davide Santoro ◽  
Nico Blüthgen
Keyword(s):  
Niche Width ◽  
Individual Specialization ◽  
Prey Mobility

scholarly journals Individual dietary specialization reduces intraspecific competition, rather than feeding activity, in black amur bream (Megalobrama terminalis)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuguo Xia ◽  
Yuefei Li ◽  
Shuli Zhu ◽  
Jie Li ◽  
Shanghao Li ◽  
...  
Keyword(s):  
Intraspecific Competition ◽  
Linear Models ◽  
Feeding Activity ◽  
Isotope Analysis ◽  
Natural Populations ◽  
Niche Width ◽  
High Plasticity ◽  
Dietary Specialization ◽  
Individual Specialization ◽  
Size Groups

Abstract Individual specialization and high plasticity in feeding activity are common in natural populations. However, the role of these two in intraspecific competition is unclear. In this study, the rhythm of feeding activity, dietary composition, niche width, niche overlap, and individual specialization was explored in four different size groups of black amur bream (Megalobrama terminalis), using microscopic identification of foregut contents and stable isotope analysis (δ13C and δ15N) of dorsal muscle. Both methods observed ontogenetic shifts in dietary preference and individual specializations, and revealed that the total niche width of large individuals was greater than small individuals. Mixed linear models indicated that feeding activity was significantly influenced by time (p < 0.0001), and no significant changes among size groups was evident (p = 0.244). Niche overlaps revealed that there was intensive diet competition between different size groups of black amur bream. Individual specialization in small juveniles was likely to be stronger than sub-adult and adult groups. Pearson’s correlation analysis revealed that the individual specialization was positively correlated with mean diet similarity within a group. The results indicated that intraspecific competition is reduced mainly by individual dietary specialization, rather than shift in feeding activity.

Use of Outlet Barriers to Prevent Fall Emigration of Brook Trout Stocked in Adirondack Lakes

2001 ◽  
Vol 21 (4) ◽  
pp. 843-854 ◽  
Author(s):  
Daniel C. Josephson ◽  
Charles C. Krueger ◽  
Patrick J. Sullivan
Keyword(s):  
Brook Trout ◽  
Adirondack Lakes

Production and Growth Efficiency of Brook Trout (Salvelinus fontinalis) in Two Adirondack Mountain (New York) Lakes Following Liming

1989 ◽  
Vol 46 (2) ◽  
pp. 333-341 ◽  
Author(s):  
Carl L. Schofield ◽  
Steven P. Gloss ◽  
Barbara Plonski ◽  
Robert Spateholts
Keyword(s):  
New York ◽  
Brook Trout ◽  
Production Efficiency ◽  
Salvelinus Fontinalis ◽  
Size Structure ◽  
Food Limitation ◽  
Growth Efficiency ◽  
Limited Range ◽  
First Year ◽  
Adirondack Lakes

Yearling and spring fingerling brook trout (Salvelinus fontinalis) stocked in two Adirondack lakes after liming in the spring of 1985 produced 10–14 kg∙ha−1yr−1 at average standing crops of 8–10 kg∙ha−1 during the first year after stocking. These values were similar to levels observed in other limed and circumneutral Adirondack lakes, which collectively support a limited range of biomass (10–20 kg∙ha−1) and production (7–16 kg∙ha−1) compared with more fertile waters in other regions. The estimated level of food consumption required to maintain initial production rates observed in the two limed lakes was 80–100 kg∙ha−1. This level of predation was sufficient to significantly alter the size structure and composition of the invertebrate prey community within a few months after stocking. However, mean production efficiency in these populations remained at levels of 20–25% and the development of adverse water quality conditions in the first year after liming appeared to be of greater significance than food limitation in regulating production and biomass of these stocked brook trout populations. Reacidification of one lake 5 mo after liming resulted in rapid declines in biomass and production as a result of both increased mortality and reduced growth.

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