Recent Submissions

  • Body shape variation of three species of Percichthys in relation to their coexistence in the Limay River basin, in northern Patagonia 

    Cussac, VE, D. Ruzzante, S. Walde, PJ Macchi, et al. 1998. "Body shape variation of three species of Percichthys in relation to their coexistence in the Limay River basin, in northern Patagonia." Environmental Biology of Fishes 53(2): 143-153.
    We describe morphological variation within and among three species of Percichthys (Perciformes, Percichthyidae) inhabiting two reservoirs within a single river drainage (Limay River) in Argentina. Two small-mouthed 'percas', ...
  • The functional response of Typhlodromus pyri to its prey, Panonychus ulmi: the effect of pollen 

    Wei, QC, and SJ Walde. 1997. "The functional response of Typhlodromus pyri to its prey, Panonychus ulmi: the effect of pollen." Experimental & applied acarology 21(10-11): 677-684.
    We looked at the effect of the presence of pollen (Typha latifolia) on the functional response of Typhlodromus pyri (Phytoseiidae) to Panonychus ulmi (Tetranychidae) in the laboratory. We found that pollen significantly ...
  • Habitat Dimensionality and Mean Search Distances of Top Predators - Implications for Ecosystem Structure 

    WHITEHEAD, H., and SJ WALDE. 1992. "Habitat Dimensionality and Mean Search Distances of Top Predators - Implications for Ecosystem Structure." Theoretical population biology 42(1): 1-9.
    No abstract available.
  • Nonbreeding-Season Drivers of Population Dynamics in Seasonal Migrants: Conservation Parallels Across Taxa 

    Calvert, Anna M., Sandra J. Walde, and Philip D. Taylor. 2009. "Nonbreeding-Season Drivers of Population Dynamics in Seasonal Migrants: Conservation Parallels Across Taxa." Avian Conservation and Ecology 4(2): 5-5.
    For seasonal migrants, logistical constraints have often limited conservation efforts to improving survival and reproduction during the breeding season only. Yet, mounting empirical evidence suggests that events occurring ...
  • Surviving historical Patagonian landscapes and climate: molecular insights from Galaxias maculatus 

    Zemlak, Tyler S., Evelyn M. Habit, Sandra J. Walde, Cecilia Carrea, et al. 2010. "Surviving historical Patagonian landscapes and climate: molecular insights from Galaxias maculatus." Bmc Evolutionary Biology 10: 67-67.
    Background: The dynamic geological and climatic histories of temperate South America have played important roles in shaping the contemporary distributions and genetic diversity of endemic freshwater species. We use ...
  • Across the southern Andes on fin: glacial refugia, drainage reversals and a secondary contact zone revealed by the phylogeographical signal of Galaxias platei in Patagonia 

    Zemlak, Tyler S., Evelyn M. Habit, Sandra J. Walde, Miguel A. Battini, et al. 2008. "Across the southern Andes on fin: glacial refugia, drainage reversals and a secondary contact zone revealed by the phylogeographical signal of Galaxias platei in Patagonia." Molecular ecology 17(23): 5049-5061.
    We employed DNA sequence variation at two mitochondrial (control region, COI) regions from 212 individuals of Galaxias platei (Pisces, Galaxiidae) collected throughout Patagonia (25 lakes/rivers) to examine how Andean ...
  • Climate-induced changes to the ancestral population size of two Patagonian galaxiids: the influence of glacial cycling 

    Zemlak, Tyler S., Sandra J. Walde, Evelyn M. Habit, and Daniel E. Ruzzante. 2011. "Climate-induced changes to the ancestral population size of two Patagonian galaxiids: the influence of glacial cycling." Molecular ecology 20(24): 5280-5294.
    Patagonia is one of the few areas in the Southern Hemisphere to have been directly influenced by Quaternary glaciers. In this study, we evaluate the influence that Quaternary glacial ice had on the genetic diversity of two ...
  • Relative importance of substrate particle size and detritus to stream benthic macroinvertebrate microdistribution 

    Culp, J. M., S. J. Walde, and R. W. Davies. 1983. "Relative importance of substrate particle size and detritus to stream benthic macroinvertebrate microdistribution." Canadian Journal of Fisheries and Aquatic Sciences 40(10): 1568-1574.
    Manipulative field experiments were conducted in Carnation Creek, British Columbia, to determine whether particle-size composition of the stony substrate influenced macroinvertebrate microdistribution if substrate detritus ...
  • Prey Exchange Rates and the Impact of Predators on Prey Populations in Streams 

    Cooper, S. D., S. J. Walde, and B. L. Peckarsky. 1990. "Prey Exchange Rates and the Impact of Predators on Prey Populations in Streams." Ecology (Washington D C) 71(4): 1503-1514.
    We present four lines of evidence that the magnitude of prey exchange (=immigration/emigration) among substrate patches has an overwhelming influence on the perceived effects of predators on prey populations. (1) An extensive ...
  • Territoriality and the evolution of character displacement and sexual dimorphism 

    Whitehead, H., and S. J. Walde. 1993. "Territoriality and the evolution of character displacement and sexual dimorphism." Ethology Ecology and Evolution 5(3): 303-318.
    In this paper we argue that even spacing of the logarithmic diameter of canine teeth in mustelids and felids as shown by DAYAN et al. (1989a, 1990) may be more likely to result from behaviourally mediated competition for ...
  • Direct and indirect species interactions influencing within-season dynamics of apple rust mite, Aculus schlechtendali (Acari, Eriophyidae) 

    Walde, SJ, JM Hardman, and CN Magagula. 1997. "Direct and indirect species interactions influencing within-season dynamics of apple rust mite, Aculus schlechtendali (Acari, Eriophyidae)." Experimental & applied acarology 21(9): 587-614.
    We conducted a series of path analyses to determine which direct and indirect species interactions were most important in determining the within-season dynamics of apple rust mite (Aculus schlechtendali) (Eriophyidae) in ...
  • Dynamics of Panonychus-Ulmi and Typhlodromus-Pyri - Factors Contributing to Persistence 

    WALDE, SJ, JP NYROP, and JM HARDMAN. 1992. "Dynamics of Panonychus-Ulmi and Typhlodromus-Pyri - Factors Contributing to Persistence." Experimental & applied acarology 14(3-4): 261-291.
    We addressed the question of persistence of predator and prey in a biological control system by examining temporal patterns of Panonychus ulmi (Koch) and its predator, Typhlodromus pyri Scheuten at two geographic locations ...
  • Feeding preference of Zetzellia mali: Does absolute or relative abundance of prey matter more? 

    Walde, Sandra J., Cebisle N. Magagula, and Madeleine Leigh Morton. 1995. "Feeding preference of Zetzellia mali: Does absolute or relative abundance of prey matter more?." Experimental and Applied Acarology 19(6): 307-317.
    The importance of the acarine predator, Zetzellia mali, in the control of phytophagous mites in apple orchards is not well understood. Zetzellia mali tends to prefer the eriophyid, Aculus schlechtendali, over the economically ...
  • A Refuge for Red Scale the Role of Size-Selectivity by a Parasitoid Wasp 

    Walde, S. J., R. F. Luck, D. S. Yu, and W. W. Murdoch. 1989. "A Refuge for Red Scale the Role of Size-Selectivity by a Parasitoid Wasp." Ecology (Washington D C) 70(6): 1700-1706.
    The presence of a physical refuge (an area where mortality due to parasitism is very low) has been demonstrated for California red scale, a pest of citrus. Density of red scale is very high, and parasitism by the principal ...
  • Variation in songbird migratory behavior offers clues about adaptability to environmental change 

    Calvert, Anna M., Stuart A. Mackenzie, Joanna Mills Flemming, Philip D. Taylor, et al. 2012. "Variation in songbird migratory behavior offers clues about adaptability to environmental change." Oecologia 168(3): 849-861.
    For seasonally migrating birds, aspects of migratory behavior, such as the use of temperate versus tropical wintering areas, may influence their ability to respond to environmental change. Here, we infer potential flexibility ...
  • How quality of host plant affects a predator-prey interaction in biological control 

    Walde, Sandra J.. 1995. "How quality of host plant affects a predator-prey interaction in biological control." Ecology (Washington D C) 76(4): 1206-1219.
    In cases of successful biological control the pest population is maintained at low densities by a natural enemy, but the mechanisms by which the predator or parasitoid manages to control the pest are often unknown. This ...
  • Estimation of Temporal Variability in Populations 

    STEWARTOATEN, A., WW MURDOCH, and SJ WALDE. 1995. "Estimation of Temporal Variability in Populations." American Naturalist 146(4): 519-535.
    A common measure of the temporal variability of a population is the standard deviation of the logarithms of successive estimated population sizes, In(D-t). This measure overestimates true temporal variability (the standard ...
  • Spatial variation in population growth rate and community structure affects local and regional dynamics 

    Trzcinski, M. Kurtis, Sandra J. Walde, and Philip D. Taylor. 2008. "Spatial variation in population growth rate and community structure affects local and regional dynamics." Journal of Animal Ecology 77(6): 1153-1161.
    1. Theory predicting that populations with high maximum rates of increase (r(max)) will be less stable, and that metapopulations with high average r(max) will be less synchronous, was tested using a small protist, Bodo, ...
  • The dynamics of Aphis pomi De Geer (Homoptera: Aphididae) and its predator, Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae), on apple in Nova Scotia 

    Stewart, HC, and SJ Walde. 1997. "The dynamics of Aphis pomi De Geer (Homoptera: Aphididae) and its predator, Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae), on apple in Nova Scotia." Canadian Entomologist 129(4): 627-636.
    The dynamics of Aphis pomi De Geer (Homoptera: Aphididae) and its predator, Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae), were studied over two seasons in a commercial apple orchard in Nova Scotia. Aphid and ...
  • Intraguild interactions and large-scale population patterns 

    Sircom, Julie, and Sandra J. Walde. 2009. "Intraguild interactions and large-scale population patterns." Journal of the North American Benthological Society 28(3): 649-658.
    Competitive interactions, including interference and intraguild predation, occur in many aquatic food webs and influence large-scale patterns of abundance, especially in lentic habitats. In a study of small coastal streams ...

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