https://knowledgecommons.lakeheadu.ca/handle/2453/789 natural resources management is stewardship of both public and private primarily (mainly) forested landscapes, with the intension of reaching a balance of ecological sustainability, economic viability and societal acceptance of prescribed land use. thu, 16 jan 2025 10:14:22 gmt 2025-01-16t10:14:22z https://knowledgecommons.lakeheadu.ca/handle/2453/4114 livestock and the functional habitat of vicuñas in ecuador : a new puzzle mclaren, brian e.; macnearney, douglas; siavichay, carlos a. whether interactions between wildlife and livestock are competitive or facilitative is context dependent. intermediary factors that explain how context (seasonal or regional characteristics of the ecological community) affects these interactions are rarely reported. we compared activity time and density in vicuñas (vicugna vicugna) introduced into the chimborazo faunal production reserve (cfpr), ecuador, to describe how they interact with livestock. we compared vicuña density in wetlands and uplands (two landscape structures) with and without livestock (two conditions) using an isodar approach. we measured, over two seasons, vicuña forage abundance, composition, preference and accessibility, time vicuñas spent vigilant, and their flight distances on approach. we tested optimal foraging theory relating to the hypothesis that time mediates behavior, and found that vicuñas were no less frequently vigilant, nor were flight distances greater, during a wet season or in habitats of greater forage abundance and accessibility. we also found no evidence that vicuña behavior was density dependent; instead, we found that more time was spent vigilant by vicuñas when they foraged near livestock in rainy regions during the dry season. although forage abundance was similar throughout cfpr during a dry season, better forage quality in areas occupied by livestock may constitute an effect of their facilitating vicuñas. a puzzling finding, because it was not explained by any of the other variables we measured, was that at low densities vicuñas selected habitat irrespective of livestock, and where their density was higher, it was doubly so adjacent to livestock. we conclude that in the cfpr, spatial heterogeneity in habitat quality determines the interactions between livestock and vicuñas. to support recommendations that minimize competition between wildlife and livestock, and to expand on descriptions of the contexts that determine the direction of species interactions, future study may require a wider sampling of the densities of sympatric large herbivores in general, and, in the cfpr, a closer resolution of spatial heterogeneity in forage plant quality. includes supplementary appendix s1. mon, 01 jan 2018 00:00:00 gmt https://knowledgecommons.lakeheadu.ca/handle/2453/4114 2018-01-01t00:00:00z https://knowledgecommons.lakeheadu.ca/handle/2453/846 sugar-frosted daphnia: an improved fixation technique for cladocera prepas, ellie egg loss by preserved daphnia was reduced from 35% to 10% by use of a chilled, as opposed to warm, solution of sucrose and formalin. first published in limnology and oceanography, (23:3) 557-559. available from http://www.jstor.org/stable/2835467 or doi: 10.4319/lo.1978.23.3.0557 sun, 01 jan 1978 00:00:00 gmt https://knowledgecommons.lakeheadu.ca/handle/2453/846 1978-01-01t00:00:00z https://knowledgecommons.lakeheadu.ca/handle/2453/845 the enigma of daphnia death rates prepas, ellie; rigler, f.h. birth rates, rates of population change, and mortality rates were computed for daphnia pulex and daphnia rosea collected at three separate stations in 2.5-ha meromictic crawford lake. birth and death rates for the same species at the three separate stations, or at the same station but living at slightly different mean depths were substantially different. a correction for tow net efficiency for young and adult animals increased birth rate values by 40%. mean finite birth rate, b, for daphnia in a thermally stratified lake is calculated from the relation [see article for formula] where for each stratum, s, e is number of eggs, d is egg development time, n is number of animals, and n is number of strata. an assumption of this formulation is that all individuals in the population behave similarly, but at crawford lake d. pulex behaves like two separate populations for at least part of the year. high death rates were calculated for d. rosea in midsummer. a comparison of observed neonates with expected neonates during this period led to the conclusion that most mortality in the population occurs either in late embryos or at hatching. first published in limnology and oceanography, 23(5), 970-988. available from http://www.jstor.org/stable/2835359 sun, 01 jan 1978 00:00:00 gmt https://knowledgecommons.lakeheadu.ca/handle/2453/845 1978-01-01t00:00:00z https://knowledgecommons.lakeheadu.ca/handle/2453/795 benefit–cost analysis of vegetation management alternatives: an ontario case study luckai, nancy j; homagain, krishnahari; shahi, chander; leitch, mathew; bell, f. wayne vegetation management practices are an integral component of forest management. in this paper, we report results of stand-level benefit–cost analyses of 12 vegetation management treatments applied at six study sites in northern ontario. forest vegetation simulator (fvsontario) was used to project gross total and merchantable volumes to 70 years of age, and buck-2 was used to optimize potential products. net present value (npv), benefit–cost ratio (bcr), and internal rate of return (irr) were calculated using 2009 constant dollars and variable real discount rates. aerial herbicide treatments produced the highest npv, bcr, and irr. internal rates of return of 4.32%, 2.90%, 2.82% and 2.50% for aerial herbicide, manual brush cutting, ground-applied herbicide, and brush cutting plus herbicide treatments, respectively, indicated that all of the vegetation management alternatives evaluated are economically viable. this is the publisher’s version of a work published in the forestry chronicle 87:2 (2011) the version on the publisher's website can be viewed at http://pubs.cif-ifc.org/doi/abs/10.5558/tfc2011-013 sat, 01 jan 2011 00:00:00 gmt https://knowledgecommons.lakeheadu.ca/handle/2453/795 2011-01-01t00:00:00z