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Burnett J.L.,University of Nebraska - Lincoln | Roberts C.P.,Nebraska Cooperative Fish and Wildlife Research Unit | Allen C.R.,U.S. Geological Survey | Brown M.B.,University of Nebraska - Lincoln
Biological Invasions | Year: 2016

Passer montanus became established in a small area of central North America following its introduction in 1870. P. montanus underwent minimal range expansion in the first 100 years following introduction. However, the North American population of P. montanus is now growing in size and expanding in geographic distribution, having expanded approximately 125 km to the north by 1970. We quantify the distance of spread by P. montanus from its introduction site in the greater St. Louis, Missouri-Illinois, USA area, using distributional (presence) data from the National Audubon Society Christmas Bird Count surveys for the period of 1951 to 2014. Linear regressions of the average annual range center of P. montanus confirmed significant shifts to the north at a rate of 3.3 km/year (P < 0.001) km/year. Linear regressions of the linear and angular distance of range center indicates significant northern movement (change in angle of mean range center; P < 0.001) since 1951. Our results quantify the extent of a northward range expansion, and suggesting a probable spread of this species northward. © 2016 Springer International Publishing Switzerland


Lotz A.,University of California at Davis | Allen C.R.,Nebraska Cooperative Fish and Wildlife Research Unit
Ecology and Society | Year: 2013

Most assessments of resilience have been focused on local conditions. Studies focused on the relationship between humanity and environmental degradation are rare, and are rarely comprehensive. We investigated multiple social-ecological factors for 100 countries around the globe in relation to the percentage of invasions and extinctions within each country. These 100 countries contain approximately 87% of the world's population, produce 43% of the world's per capita gross domestic product (GDP), and take up 74% of the earth's total land area. We used an information theoretic approach to determine which models were most supported by our data, utilizing an a priori set of plausible models that included a combination of 15 social-ecological variables, each social-ecological factor by itself, and selected social-ecological factors grouped into three broad classes. These variables were per capita GDP, export-import ratio, tourism, undernourishment, energy efficiency, agricultural intensity, rainfall, water stress, wilderness protection, total biodiversity, life expectancy, adult literacy, pesticide regulation, political stability, and female participation in government. Our results indicate that as total biodiversity and total land area increase, the percentage of endangered birds also increases. As the independent variables (agricultural intensity, rainfall, water stress, and total biodiversity) in the ecological class model increase, the percentage of endangered mammals in a country increases. The percentage of invasive birds and mammals in a country increases as per capita GDP increases. As life expectancy increases, the percentage of invasive and endangered birds and mammals increases. Although our analysis does not determine mechanisms, the patterns observed in this study provide insight into the dynamics of a complex, global, social-ecological system. © 2013 by the author(s).


Chizinski C.J.,Nebraska Cooperative Fish and Wildlife Research Unit | Chizinski C.J.,University of Nebraska - Lincoln | Martin D.R.,Nebraska Cooperative Fish and Wildlife Research Unit | Martin D.R.,University of Nebraska - Lincoln | And 4 more authors.
Fisheries Research | Year: 2014

Spatial layout of waterbodies and waterbody size can affect a creel clerk's ability to intercept anglers for interviews and to accurately count anglers, which will affect the accuracy and precision of estimates of effort and catch. This study aimed to quantify angling effort and catch across a spatially complex system of 19 small (<100. ha) lakes, the Fremont lakes. Total (±SE) angling effort (hours) on individual lakes ranged from 0 (0) to 7,137 (305). Bank anglers utilized 18 of the 19 lakes, and their mean (±SE) trip lengths (hours) ranged from 0.80 (0.31) to 7.75 (6.75), depending on the waterbody. In contrast, boat anglers utilized 14 of the 19lakes, and their trip lengths ranged from 1.39 (0.24) to 4.25 (0.71), depending on the waterbody. The most sought fishes, as indexed by number of lakes on which effort was exerted, were anything (17 of 19 lakes), largemouth bass Micropterus salmoides (15 of 19 lakes), and channel catfish Ictalurus punctatus (13 of 19 lakes). Bluegill Lepomis machrochirus, crappie Pomoxis spp., and largemouth bass were caught most frequently across the lakes, but catch rates varied considerably by lake. Of the 1,138 parties interviewed, most parties (93%) visited a single lake but there were 77 (7%) parties that indicated that they had visited multiple lakes during a single day. The contingent of parties that visited more than one lake a day were primarily (87%) bank anglers.. The number of lake-to-lake connections made by anglers visiting more than one waterbody during a single day was related to catch rates and total angling effort. The greater resolution that was achieved with a lake specific creel survey at Fremont lakes revealed a system of lakes with a large degree of spatial variation in angler effort and catch that would be missed by a coarser, system-wide survey that did not differentiate individual lakes. © 2013 Elsevier B.V.


Turek K.C.,University of Nebraska - Lincoln | Turek K.C.,Nebraska Cooperative Fish and Wildlife Research Unit | Pegg M.A.,University of Nebraska - Lincoln | Pope K.L.,University of Nebraska - Lincoln | Pope K.L.,U.S. Geological Survey
Ecology of Freshwater Fish | Year: 2015

Laboratory and in-stream enclosure experiments were used to determine whether rainbow trout Oncorhynchus mykiss influence survival of longnose dace Rhinichthys cataractae. In the laboratory, adult rainbow trout preyed on longnose dace in 42% of trials and juvenile rainbow trout did not prey on longnose dace during the first 6 h after rainbow trout introduction. Survival of longnose dace did not differ in the presence of adult rainbow trout previously exposed to active prey and those not previously exposed to active prey (χ12 = 0.28, P = 0.60). In field enclosures, the number of longnose dace decreased at a faster rate in the presence of rainbow trout relative to controls within the first 72 h, but did not differ between moderate and high densities of rainbow trout (F2,258.9 = 3.73, P = 0.03). Additionally, longnose dace were found in 7% of rainbow trout stomachs after 72 h in enclosures. Rainbow trout acclimated to the stream for longer periods had a greater initial influence on the number of longnose dace remaining in enclosures relative to those acclimated for shorter periods regardless of rainbow trout density treatment (F4,148.5 = 2.50, P = 0.04). More research is needed to determine how predation rates will change in natural environments, under differing amounts of habitat and food resources and in the context of whole assemblages. However, if rainbow trout are introduced into the habitat of longnose dace, some predation on longnose dace is expected, even when rainbow trout have no previous experience with active prey. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.


Deboer J.A.,Grand Valley State University | Deboer J.A.,Nebraska Cooperative Fish and Wildlife Research Unit | Ogren S.A.,Little River Band of Ottawa Indians | Holtgren J.M.,Little River Band of Ottawa Indians | Snyder E.B.,Grand Valley State University
American Midland Naturalist | Year: 2011

Resident fish exhibited higher short-term resiliency than did non-resident fish to a 100 y flood in a low-gradient stream. In Jun. 2008, a substantial flood (400% higher than mean daily discharge) occurred in the Big Manistee River watershed in Michigan. Pre-and post-flood fish communities were sampled at two sites on Bear Creek, a 4th order tributary of the Big Manistee River. One site was low-gradient and dominated by sand; the second site was higher gradient and dominated by large woody debris and fine gravel. At both sites, post-flood fish communities were similar to pre-flood communities (Morisita's Index (Im) ≈ 0.8), especially for resident fish (Im ≈ 0.95). Total Catch Per Unit Effort (CPUE) of non-resident fish declined dramatically (5.2 to 1.4 fish per minute) in post-flood surveys, whereas CPUE of resident fish increased slightly (4.3 to 4.7) post-flood. Individual species response was site-dependent and mixed: CPUE of mottled sculpin and burbot increased post-flood, whereas CPUE of other resident species decreased. Resident non-native (i.e., rainbow trout) and non-resident non-native salmonids (i.e., Chinook salmon) experienced the most negative response, suggesting life-history traits of native fish encompass evolutionary adaptations to better persist through extreme disturbance events as compared to non-native salmonids. © 2011, American Midland Naturalist.

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