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A decline in the size of fish within a population is concerning. Large-sized fish are ecologically important and valued for social and economic reasons. Following widespread collapses from angling overharvest, the densities of Walleyes Sander vitreus in Albertas lakes increased rapidly with large-minimum-size limits. Anglers were unhappy, however, as catch rates increased (>1 Walleyes*hour-1) but fish remained small and did not exceed the minimum size limit. The two alternate explanations for the small, yet old Walleyes were either compensatory growth because of high density (stunting) or size-selective mortality (overfishing). Size-selective mortality has evolutionary consequences. Paradoxically, the management solutions for these problems are in opposition (more harvest versus less harvest), and a wrong diagnosis could exacerbate the problem. I used nested hypotheses, and implemented active adaptive management at several Alberta lakes, to diagnose the causal mechanism creating the small fish problem. For inferences on the source of the mortality, I analysed backcalculated growth rates from pelvic fins. Walleyes that had fast-growth to an early maturity, and then subsequent slow-growth, had greater survival. This hockey stick-shaped growth allows for successful reproduction while the Walleyes remain below the minimum size limit, avoiding harvest. Using changes to sport fishing regulations, I then modified angler effort and harvest at four different Alberta lakes to increase or decrease size-selective harvest and Walleye densities. I found that size-selective mortality from angling rapidly truncated the population-size structure. With concerns of evolutionary consequences because of evidence of size selective harvest, I used an age- and size-structured, single-species model, parameterized with data from Albertas Walleye fisheries, to evaluate the selectiveness of various management regulations. I found that the 50-cm minimum size limit used to recover Albertas Walleye populations did indeed select for the hockey stick life history, although this regulation allowed for sustainable populations (>5 Walleyes*hectare-1) and angler effort up to 16 angler-hours*ha-1*year-1. The optimal regulation to reduce life history selection and allow for population sustainability was a 40-50 cm harvest-tag regulation. This regulation reversed the selection for the hockey stick life history, yet produced sustainable fish densities and allowed angler effort up to 30 angler-hours*ha-1*year-1. However, increasing angler-noncompliance reduced the sustainability of this regulation. / Wildlife Ecology and Management

White-tailed deer (Odocoileus virginianus) have been intensively studied across their range. However, many aspects of the white-tailed deer’s ecology have not been studied or are difficult to study. The advent of global positioning system (GPS) collar technology and molecular genetics techniques now allows researchers to collect fine-scale and cryptic phenomena. In addition, selective harvest of male white-tailed deer, based on antler size, has not been critically evaluated. Thus, development and use of quantitative genetics models will be useful for elucidating the effects of selective harvest on mean population antler size. I used GPS collar technology to further understand white-tailed deer movement ecology. First, I determined the efficacy and influence of a high-tensile electric fence (HTEF) on deer movements. The HTEF controlled deer movements when properly maintained and had little influence on deer spatial dynamics, making it a safe and cost-effective alternative to traditional fencing. Second, I studied fine-scale deer movements using GPS collars collecting locations every 15 minutes. Hourly deer movements were greatest in the morning and evening. Parturition and rut influenced movements of females and males, respectively whereas weather and moon phase had minimal influence on movements. Molecular genetics techniques are becoming more widespread and accessible, which may allow insight into the link between genetics and antler size. I found deer in 3 diverse populations from Mississippi, Oklahoma and Texas were relatively heterozygous and unrelated. Groups of deer with similar antler characteristics did not appear to be inbred or share common ancestors. In addition, there was not a strong link between individual multi-locus heterozygosity and antler points or score. Selective harvest has been implicated in causing negative evolutionary and biological responses in several ungulate species. To better determine how selective harvest (i.e., culling; the removal of deer with inferior antlers) affects white-tailed deer antler size, I used quantitative genetic models to simulate response of deer antlers to selection. In simulated controlled breeding situations response to selection was rapid, resulting in improvement in antler size. In simulated free-ranging populations response of antler size to selection was slow and only resulted in minimal increases in antler points after 20 years.

Minimising the potential impact of forest management requires an understanding of the key elements that maintain forest diversity and its role in ecological processes. Invertebrates are the most diverse of all biota and play important roles in maintaining forest processes. However, little is known about invertebrates in New Zealand's beech forests or the degree to which selective beech harvest might impact on their diversity and ability to carry out ecosystem processes. Studying ecosystem responses to disturbance is considered vital for understanding how ecosystems are maintained. One of the main objectives of this research was to assess whether litter-dwelling invertebrates were susceptible to the impacts of selective harvest and, if so, whether they could be used as indicators of forest health. Changes in invertebrate diversity could have important implications for nutrient cycling and primary production in forests. Litter-dwelling invertebrates contribute to the process of decomposition by increasing the surface area of the leaves, mixing soil organic matter and by infecting leaf particles with soil microbes. This investigation into the function of invertebrates in beech forest was carried out in the context of ecological theories which relate diversity to ecosystem stability and resilience. A replicated study was established in Maruia State Forest (South Island, New Zealand) to assess the potential biotic and abiotic impacts of sustainable beech harvest. Litter-dwelling invertebrates and environmental factors were monitored during 1997, before harvest, to determine how much variability there was between study sites. Specifically, litter pH, light intensity, litter fall, litter temperature, moisture as well as invertebrate abundance and diversity were compared before and after selective harvest. On 17 January 1998, two to three trees were selectively harvested from three of the nine study sites. On 15 February 1998 a similar number of trees were winched over or felled manually to create artificial windthrow sites. The remaining three undisturbed sites were used as controls. Invertebrates belonging to the detritivore guild were assessed from litter samples and a series of litter-bags containing pre-weighed leaf litter which were placed in each of the sites to assess rates of litter decomposition. Millipedes (Diplopoda: Polyzoniidae, Schedotrigonidae, Dalodesmidae, Habrodesmidae, Sphaerotheridae), earthworms (Oligochaeta: Annelida), tipulid larvae (Diptera: Tipulidae), weevils (Coleoptera: Curculionidae), moth larvae (Lepidoptera: Oecophoridae, Tortricidae and Psychidae), slaters (Isopoda: Styloniscidae), Oribatid mites (Acarina: Cryptostigmata) and landhoppers (Crustacea: Amphipoda) were extracted from the litter-bags and their abundance and diversity was compared between the three treatments. Weight loss from the litter-bags and the carbon and nitrogen content of litter were used to measure the rate of decomposition in each treatment. An additional study investigated whether exclusion of invertebrates from leaf litter resulted in reduced rates of decomposition. The results indicated that there was an increase in light intensity and a small increase in temperature following selective harvest and artificial windthrow. There was no significant difference in litter moisture or the amount of litter fall between the treatments. Invertebrate abundances were significantly affected by season but did not appear to be affected by selective harvest or artificial windthrow. The diversity of invertebrates remained relatively constant throughout the year, as did the rate of decomposition. When invertebrates were excluded from the leaf litter there was no consequential effect on the rate of litter decomposition. This suggests that there may be compensatory mechanisms taking place between the trophic levels of the food web to maintain processes and that direct links between invertebrates and decomposition are relatively weak. In conclusion, it appears that the effects of selective beech harvest on forest-floor processes were minimal and are comparable to those created by natural windthrow disturbance. It also appears that macroclimatic effects such as seasonal climatic effects have a large effect on forest biota. As none of the invertebrates studied appeared to be detrimentally affected by selective harvest and as there was no direct link demonstrated with decomposition, it was considered inappropriate to advocate the use of this group of invertebrates as indicators of sustainable forest management. The results from this study provide information which may help inform decisions on the future management of diversity in beech forest ecosystems.