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Journal ArticleDOI

Wildlife Management Techniques

01 Mar 1970-Journal of Range Management (Wildlife Society)-Vol. 23, Iss: 2, pp 150
About: This article is published in Journal of Range Management.The article was published on 1970-03-01. It has received 106 citations till now. The article focuses on the topics: Wildlife management.
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Journal ArticleDOI
TL;DR: A regional network of preserves, with sensitive habitats insulated from human disturbance, might best perpetuate ecosystem integrity in the long term.
Abstract: Land managers have traditionally assumed that achieving maximum local habitat diversity will favor diversity of wildlife. Recent trends in species composition in fragmented landscapes suggest, however, that a more comprehensive view is required for perpetuation of regional diversity. A regional network of preserves, with sensitive habitats insulated from human disturbance, might best perpetuate ecosystem integrity in the long term. (Accepted for publication 5 May 1983)

575 citations


Cites background from "Wildlife Management Techniques"

  • ...For example, in a chapter of a widely used wildlife management text (Giles 1971), Yoakum and Dasmann (1971) urge managers to "develop as much edge as possible" (italics mine), because "wildlife is a product of the places where two habitats meet."...

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Journal ArticleDOI
TL;DR: In this paper, the authors developed landscape-based ecologically scaled landscape indices (ELSI) and modeled species spatial distribution across three spatial scales (landscape-level, element-level and local habitat-level) and found that predator species view landscape fragmentation at different spatial scales and demonstrate strong interspecific differences in their response to elements of the landscape.

282 citations

Book ChapterDOI
01 Jan 1979
TL;DR: This chapter discusses in turn three approaches to understanding individuals’ spatial relationships: quantitative specification of patterns of spacing; analysis of the behavioral mechanisms that control spacing; and identification of the effects of natural selection on the evolution of spacing.
Abstract: Animals of the same species are rarely distributed randomly. Each individual’s movements are influenced by those of its neighbors, with the result that any population exhibits a characteristic pattern of individuals’ locations and activities in space.1 In this chapter, we discuss in turn three approaches to understanding individuals’ spatial relationships: quantitative specification of patterns of spacing; analysis of the behavioral mechanisms that control spacing; and identification of the effects of natural selection on the evolution of spacing. This division separates discussion of the proximate controls of spacing, in our initial sections, from consideration of the ultimate controls, with which we conclude.

160 citations

Journal ArticleDOI
01 Apr 1994-Oikos
Abstract: Temporal variation in animal population size and the related concept of population stability are of substantial interest to animal ecologists (e.g., MacArthur 1955, Holling 1973). Empirical studies of variation in population size are not new (e.g., Watt 1964) but have become especially popular in recent years. Recent empirical work has included interesting research on the relationships between temporal variation in population size and such factors as extinction probability (Karr 1982, Pimm et al. 1988, Schoener and Spiller 1992, Tracy and George 1992), mean population density (Taylor and Woiwod 1980), latitude (Wolda 1978), human disturbance (Pechmann et al. 1991), body size (Gaston 1988, Gaston and Lawton 1988), food habits (Gaston and Lawton 1988, Redfearn and Pimm 1988), geographic range (Gaston 1988, Gaston and Lawton 1988), and taxonomy (Connell and Sousa 1983, Schoener 1985). However, estimation of temporal variation in population size is not a simple matter (Greenwood 1989, Mc Ardle 1989, McArdle et al. 1990). McArdle et al. (1990: 439) recently discussed "problems associated with the measurement and interpretation of population density variability that have confounded most, if not all, previous studies of the subject". These problems include "artefactual patterns" induced by commonly used transformations and misleading conclusions resulting from comparisons of populations sampled at different spatial and temporal scales. McArdle et al. (1990) also argued that the dependence of population variability on mean density should be considered in making comparisons of variability among species and populations. Recent contributions to the literature conclude with statements emphasizing the importance of properly estimating and comparing population variability and recommending additional statistical and biological work on the topic (McArdle et al. 1990, Schoener and Spiller 1992). Despite the fairly extensive literature on population variability and its estimation, there has been little discussion of the fact that virtually all of the empirical work has relied on estimates or indices to animal abundance (see McArdle and Gaston 1993). That is, estimates of population variability are not based on a time series of true population sizes measured without error, but on a series of estimates or indices (count statistics assumed to be related to population size by a proportionality constant, see Lancia et al. in press). Measures of population variability computed using point estimates of population size over time represent the sum of at least two conceptually distinct variance components. One component is temporal variation in actual population size and is relevant to interesting biological hypotheses. Another component is "sampling variation", defined here as the variation associated with the population estimation procedure. This component is sometimes called "error of estimation" and occurs whenever it is impossible to directly enumerate all individuals in the population. This component is not relevant to biological hypotheses and should not be included in measures of population variability computed for the purpose of addressing such hypotheses. We believe that the inclusion of this unwanted variance component in previous studies of population variability is at least as serious a problem as those associated with transformations and scale discussed by McArdle et al. (1990). For studies in which population size is estimated rather than indexed, it is usually possible to estimate the sampling variance of the population estimates. This component can then be subtracted from the total variance (e.g., based on point estimates) to estimate the variance component of interest. This basic approach has been used to estimate variance of survival probabilities among replicate groups of animals receiving different experimental

152 citations

Journal ArticleDOI
01 Mar 1993-Ecology
TL;DR: Ostriches had a frugal water economy when compared to other nonpasserine birds, with both subadults and adults having lower WIRs than predicted, suggesting that adults may be more efficient at acquiring resources.
Abstract: We measured the field metabolic rate (FMR) and water influx rate (WIR) of the largest species of bird, the Ostrich (Struthio camelus), which lives in the Namib desert, one of the driest regions on earth. Along with doubly-labeled water (DLW) mea- surements of FMR and WIR, we examined the availability of plants in various habitats, the plants selected by Ostriches, and the daily activity patterns of these birds. During 6-8 d periods, adult Ostriches (88.25 kg) had an FMR of 18 040 kJ/d, while subadult birds (50.75 kg) metabolized energy at a rate of 15 428 kJ/d. Adult energy expenditure was 26% lower than predicted, but subadults had an FMR nearly equivalent to expectation, suggesting that adults may be more efficient at acquiring resources. Conclusions remain tentative because data for the Ostrich exceed previous data used for allometric equations by almost an order of magnitude. Gravel and stoney plains together accounted for 84% of the study area, whereas washes occupied < 1%. Vegetation cover was sparse in all habitats, varying between 7 and 19% in most areas, but comprising 15% along drainage lines. Ostriches foraged on gravel plains nearly 65% of their daytime hours and 25.5% of their day in washes. They consumed a narrow range of green plants with Monechma arenicola, Schmidita kalahariensis, Blepharis spp., Trianthema triquetra, and Dicoma capensis representing the principal items in the diet. From a time-activity budget, Ostriches spent 7.5 h of their 24-h day walking, and roosted at night for 11.5 h. Transport between food patches accounted for 62.2% of FMR while nighttime rest was 19.0%. Preening and other maintenance behaviors were responsible for < 1% of the Ostriches' energy budget. Ostriches had a frugal water economy when compared to other nonpasserine birds, with both subadults and adults having lower WIRs than predicted. Values for WIR were higher than allometric predictions based on four other desert birds previously studied, but because Ostriches are two orders of magnitude larger in body mass, firm conclusions await further data. Calculations of the water economy index (WEI), the ratio of water influx to FMR (in millilitres of water per kilojoule), showed that Ostriches conserved water like smaller desert birds. Four species of desert birds had WEI values averaging 0.16 mL/kJ; values for the Ostrich averaged 0.17 mL/kJ. An itemized water budget suggested that adults did not drink during the periods of observation, while water intake by subadults averaged 729 ml/d. This suggests that adults may have lower minimum water requirements than subadults. Combining available data for FMR and WIR with data for the Ostrich, we constructed new allometric equations that nearly span the entire range of bird size and include 62 species of birds.

139 citations