I studied the grayling populations in 4 tributaries of Becharof Lake. The grayling in Ruth River, and Salmon, Featherly and Becharof Creeks appear to be independent populations, with high fidelity to specific streams. All populations overwintered in the lake and migrated into the streams when water temperatures reached about 2.5 C. These populations contained some of the largest grayling in the state; generally >50% of the population exceeding 6 years in age and had fork lengths >400 mm. Interstream movement rates were about 2%, but intrastream movement was higher (18%). Spring migration into the streams extended from May-July. This extended migration may have invalidated the assumption of a closed population, and resulted in higher than actual estimated abundance. Abundance ranged from a low of 33 grayling/Km in Featherly Creek to a high of 230 grayling/Km in Becharof Creek. Survival rates were similar in all streams.

The Gila topminnow (Poeciliopsis occidentalis occidentalis) is federally and state listed as endangered. My objectives were to quantify microhabitat use and preference of topminnow in the field and test responses to controlled laboratory settings. In Cienega Creek, topminnow preferred stream margins where the water was calm, shallow, and contained aquatic vegetation. Topminnow were always near the water surface. Water temperature averaged 1-2 C warmer in areas occupied by fish. In outdoor pools, groups of topminnow consistently preferred cover provided over no cover and selected the upper 1/3 of the water column. Plastic strips, elicited the strongest response and styrofoam sheets elicited the weakest response. Topminnow did not show a consistent preference for cover when tested singly in aquaria, but showed a strong preference for calm water. Responses of topminnow to tests in aquaria were not in concordance with behavior observed in Cienega Creek or in tests conducted in outdoor pools.

No description available.

Food insecurity and malnutrition are issues that affect approximately one in seven people worldwide and climate change threatens to increase those risks in the future. Many of the policies that address future food systems emphasize resilience - a combination of flexibility in the face of disturbance and the capacity to adapt to change. In Sub-Saharan Africa many households employ livelihood systems that are highly sensitive to change and cannot adapt well to changing environmental conditions, leaving them vulnerable and reliant on coping strategies. Wild edible plants (WEPs) are a particularly common and effective strategy for coping with food insecurity. This research, conducted in rural Eastern Province, Kenya, suggests that certain demographic characteristics and access conditions are correlated with greater use of WEPs. Food insecure households, and those families lacking off-farm income or with lower levels of assets were found to consume WEPs with greater frequency. Access to WEPs was also a major factor, with smaller farm sizes and increased distance to harvest areas correlated significantly to lower levels of WEP use. After reviewing the existing laws pertaining to State forests, privatization trends of communal land and an increasingly formalized management regime for private land tenure, I find that access to WEPs is declining. Development practitioners', governments' and donor organizations' focus on commercialization and commodity value has led extension agents and land owners to ignore the subsistence value of WEPs, especially for poorer populations. The household characteristics identified in this study are specific enough that they can be used to determine the demographic groups that rely heavily on WEPs, and the access conditions that are likely to increase the ability of those vulnerable groups to employ WEPs as a coping strategy to increase system resilience. Protecting and promoting sustainable use of WEPs could increase the current contribution of these valuable resources to household food security, especially if policies can be tailored for the groups that depend on them the most. / L'insécurité alimentaire et la malnutrition affectent environ une personne sur sept à travers le monde et le changement climatique menace d'accroître ces risques à l'avenir. La plupart des politiques qui concernent les systèmes alimentaires futures mettent en relief la résilience - une combinaison de flexibilité face à la perturbation et la capacité de s'adapter au changement. En Afrique sub-saharienne de nombreux ménages utilisent des stratégies de moyens de subsistance qui sont très sensibles aux changements et ne peuvent bien s'adapter aux conditions environnementales, ce qui les rendent vulnérables et dépendants des stratégies de survie. L'utilisation des plantes sauvages comestibles (WEPs) représente une stratégie particulièrement commune et efficace. Cette recherche réalisée dans la Province de l'Est du Kenya suggère que certaines caractéristiques démographiques et conditions d'accès sont en corrélation avec une augmentation de la consommation de WEPs. Les lois forestières dans les zones de conservation, la privatisation des terres communales, et la formalisation des régimes de gestion contribuent à la réduction d'accès aux ressources WEP, tout en mettant l'accent sur la commercialisation et la valeur de ces produits pour l'export, ce qui a provoqué les agents de vulgarisation et les propriétaires fonciers à ignorer la valeur substantielle des WEPs, en particulier pour les populations les plus pauvres. La protection et la promotion de l'utilisation durable des WEPs pourraient augmenter la contribution actuelle de ces ressources importantes à la sécurité alimentaire des ménages, et d'autant plus si les politiques peuvent être adaptées pour les groupes qui dépendent le plus sur les WEPs.

<p>The management and research of mule deer (<i>Odocoileus hemionus </i>) in Colorado and throughout the Rocky Mountain West is an exciting arena for wildlife professionals as the prevailing view among biologists, managers, researchers, hunters, wildlife viewers and general wildlife enthusiasts is that they would like to see more deer on the landscape. </p><p> In Chapter 1, I used 4 years of data and 8 study units to evaluate the effect of habitat management on the overwinter survival of mule deer fawns. Habitat management consisted of different levels of habitat management efforts: reference study units received no habitat management, traditional habitat treatment units received mechanical disturbance and advanced habitat treatment units were comprised of both mechanical disturbances as well as follow-up chemical control of weeds and reseeding with desirable browse species. Mule deer fawns that overwintered on areas that received both a traditional treatment as well as follow-up treatments experienced an improvement in survival (<i> &Scirc;</i> = 0.768, SE = 0.085) over deer on winter range without habitat treatments (<i>&Scirc;</i> = 0.675, SE = 0.112). When partitioned into different levels of treatment intensity, mule deer inhabiting winter range that advanced treatments (i.e., both traditional treatments and follow-up treatments) experienced higher survival (<i>&Scirc;</i> = 0.768, SE = 0.0849) than deer on areas that experienced only traditional treatments (<i>&Scirc;</i> = 0.687, SE = 0.108), which in turn experienced higher survival than in areas that had received no treatments (<i>&Scirc; </i> = 0.669, SE = 0.113). </p><p> In my second chapter, I relied on recent advancements in abundance estimation methodologies to determine if habitat management strategies increased mule deer density. In order to estimate mule deer density, I conducted annual helicopter mark-resight surveys across the 8 study units that were utilized in chapter 1. Resighting probabilities (range 0.070&ndash;0.567) were best modeled as an interactive function of study unit and year, although sampling method was also important. A consistent pattern of higher deer density on advanced treatment study units was not observed despite its being the primary hypothesis of the study. Total deer densities did vary by latitude with 20&ndash;84 deer/km&sup2; in southern study units and 4&ndash;12 deer/km&sup2; in northern study units. I conclude that if population density is to be used as a population response variable, it only be used in tandem with other, possibly more sensitive parameters, such as overwinter survival of mule deer fawns. </p><p> In my third chapter, I investigate the relationships between habitat, body condition, and life history characteristics. With the increased availability of portable ultrasound machines and the refinement of hormonal assays, assessment of ungulate body condition has become a more accessible monitoring strategy. I employed body condition scoring, estimation of % ingesta-free body fat (%IFBF) and assessment of thyroid hormones (FT4 and FT3) as metrics to determine if landscape-level habitat manipulation affected body condition of adult (&ge;1.5 years old) female mule deer. </p><p> For my final chapter, I assimilate the knowledge and information gained from my first 3 chapters with the existing knowledge base surrounding mule deer population dynamics and population limitation within Colorado. Such reviews have been conducted periodically (e.g., 1960s and late 1990s) and have been precipitated by mule deer population declines. A dramatic decline in mule deer populations was detected during the final years of my field research but the underlying cause of this decline is yet to be determined. (Abstract shortened by UMI.)</p>

No description available.

Bush encroachment is currently of great concern in Marakele Park. The main motivation for this study, conducted during the 2003/2004 and 2004/2005 seasons, was to determine whether mechanical bush thinning, executed with a mechanical mulc her, namely the Barko Tractor, was successful in solving the bush encroachment problem in the areas where it was applied. The specific objectives of this study were to identify, describe and interpret the plant communities of a section of Marakele Park, and to establish the influences of the thinning treatments on the dynamics of the ecosystem, more specifically the regrowth and browse production of the woody plants, the species composition and dry matter (DM) yield of the herbaceous layer and the short term changes in the soil. Eight experimental plots (3 treatments, 3 controls, 2 coppice) were selected in three veld types (Acacia mellifera â Grewia flava, Combretum apiculatum â Grewia flava and Acacia erubescens â Dichrostachys cinerea), in which tree thinning was applied during 2002 and 2003. Each plot was 100 m x 200 m (20 000 m2 = 2 ha) in size. The vegetation of the plots was phytosociologically studied during the 2003/2004 season with the aid of the Braun-Blanquet vegetation sampling method. A total of 80 relevés were surveyed and upon analysis 3 major communities, 7 communities, 6 sub-communities and 3 variants were identified. The woody layer was quantified with a quantitative description technique, which is incorporated in the BECVOL-model. A step point-method and the Ecological Index Method were used to determine the species composition and veld condition of the herbaceous layer, respectively, and a harvesting method was used to determine the DM yield and the associated grazing capacity. The thinning treatments resulted in an initial decreased number of woody plants, but since no follow-up treatments were applied, a large number of new seedlings have since established and the majority of cut-plants coppiced vigorously. However, approximately three years after the thinning treatments the leaf biomass (ETTE ha-1) of the woody layer increased due to regrowth and re-encroachment to a point where negative interactions between the woody and herbaceous plants, as a result of competition for soil water and nutrients, were evident again. The species diversity of the herbaceous layer increased after the thinning treatments, but species normally associated with disturbed and overgrazed veld still dominated. It was concluded that the herbaceous layer of Marakele Park is in a poor ecological state and indications are that it is still deteriorating. The herbaceous DM yield did not respond to the thinning treatments as expected, except in areas protected from grazing herbivores. As a result, the grazing capacity of the Park was comparatively low. It is clear that Marakele Park is currently overstocked with various game species, especially of high density, selective short grass grazers. Thinning treatments will therefore not be successful unless the herbivore game numbers are reduced. Few soil variables changed significantly as a result of the thinning treatments, but in view of the fact that soil enrichment is a slow process, monitoring of the soil variables is recommended. The specific soil propertie s did, however, have a decisive influence on the vegetation type. The Combretum apiculatum â Grewia flava plots occurred on relatively shallow, gravelly soil, while the Acacia dominated plots occurred on deeper, more fertile soil. It was also concluded that the Barko Tractor, due to its size and weight, had a negative impact on the soil, mainly in the form of soil compaction. Subhabitat differentiation, rainfall and herbivory played an important role in the study area and indicated that the vegetation of Marakele Park displays both equilibrial and non-equilibrial trends. The high grazing pressure, together with the high incidence of coppice and re-encroachment of woody plants after the initial thinning treatments, as well as the lack of follow-up treatments, effectively neutralised the success of the mechanical bush thinning treatments. In order to restore these thinned areas from re-encroachment it will be necessary to cut the plants again and combine this effort with a cut-stump treatment (chemical herbicide). Due to the negative impact of the Barko Tractor, it should not be used again during any follow-up operation.

Not available

A study was conducted to evaluate the effects of different dietary energy levels on the productive (ADG, FCR, body weight, carcass) and reproductive (scrotum, testes, semen) characteristics of young Dorper rams. The study was carried out in two phases at the University of the Free State campus in Bloemfont ein, South Africa. Out of a group of 60 rams, 36 animals that were successfully trained for semen collection with the aid of an artificial vagina (AV), were selected to be part of this study and housed in individual metabolic cages. During phase 1 of this study, 36 (11 to 12 months old) Dorper rams with a mean initial body weight of 42.0 ± 0.52kg were randomly allocated to 3 groups (n=12 per group). Each group was randomly assigned to one of 3 experimental diets (treatments), formulated on a crude protein, degradable protein, calcium and phosphorus equivalent basis. A medium energy (Me) diet was formulated according to the National Research Council standards (NRC) for young growing rams to serve as the control diet. The metabolisable energy (ME) content of this diet (Me) was increased by 15 % for the high energy (He) and decreased by 15% for the low energy (Le) diets respectively. The actual ME levels for the Le, Me, He: were 6.52, 8.09 and 9.39 MJ/kg, respectively. The rams received the diets and fresh water ad libitum during a 127 day trial period and were weighed once a week. Their ADG, FCR and ME/kg weight gain calculated and compared amongst groups. During this trial, a digestibility trial was conducted for 7 days (during week 14 of the trial), using 5 randomly selected animals from each treatment group. The amount of feed offered and consumed by each animal as well as the feaces excreted daily were recorded. The chemical composition of the diets and the feaces (dry matter, energy, crude and degradable protein) were determined. Semen was collected from each ram, every forthnight for 3 consecutive days, with the aid of an AV and evaluated for volume, overall sperm motility, forward progression, sperm concentration, % live sperm and % normal sperm. The semen samples were then diluted (using a one-step dilution method with a cryodiluent containing 5% glycerol), packed in 0.25ml plastic straws, equilibrated for 4 hours and cryoperserved (frozen) in liquid nitrogen vapour (-70 ºC). One week after freezing, the semen was thawed (38 ºC for 30 seconds) and evaluated for the same qualitative parameters as the fresh semen. The results were compared amongst groups for each collection time, using ANOVA for repeated measures analysis procedures of SAS. The energy level of the diet and the collection week as well as their interaction was used as independent variables, while the different semen parameters cons idered were the dependent variables in the model. When means differed significantly, the Tukey method was used to compare means. At the end of this trial period, 6 rams per group were randomly selected and slaughtered at a commercial abbatoir. After slaughtering the carcass characteristics (cold carcass weight, dressing percentage, carcass grade, shoulder circumference, buttock circumference, backfat thickness, eye muscle area, marbeling and kidney fat) were recorded and compared amongst groups. The scrotum (total weight, skin weight, fat and circumference), testes (volume and weight) and epid ydimis (weight and volume) characteristics were also recorded and compared between groups, using ANOVA procedures of SAS. When means differed significantly the Tukey method was used to compare means. From the independent variables considered in the model, only the diet (ME level) had a significant effect on the parameters considered. In general, an increase in dietary energy level resulted in higher growth rates, better feed conversion rates, heavier carcasses, higher dressing percentages and greater fat deposition, both in the carcass, around the kid neys and in the scrotum (particularly in the neck region, over the testicular vascular cone). It seems that the energy requirements recommended by the NRC (1985) are not applicable for early mature Dorper replacement ram lambs, as those in the He group, (real ME level similar to NRC recommendations) deposited excessive fat in their body. Despite the significant differences induced by the He on the growth performance, carcass characteristics as well as on the scrotal and testicular characteristics of Dorper rams, no detrimental effects were recorded in their semen quantity, quality and cryotole rance. During the following 90 days (phase 2), the remaining rams (n=6 per group) were further maintained on the Le diet for 90 days. This was done to simulate the situation when overconditioned (fat) rams bought at auctions are placed on low energy diets (veld). Other objectives of this trial phase were to evaluate if the fat deposits accumulated in the scrota of rams fed on high energy diets are mobilized during subsequent periods of moderate nutritional restriction and if these nutritional restrictions induce any changes on the semen characteristics of rams. During this phase of the trial, semen was collected, with the aid of an AV, every 3 weeks during 2 consecutive days. The semen was evaluated using the same procedures described for phase 1 of this study. The rams were slaughtered at the end of this trial period (90 days) at a commercial abattoir. After slaughtering, the carcass characteristics (cold carcass weight, dressing percentage, carcass grade, shoulder circumference, buttock circumference, backfat thickness, eye muscle area, marbeling and kidney fat), the testicular (volume and weight), the scrotal (weight, circumference, skin weight and fat) and the epididymis characteristics (weight and volume) were also recorded and compared amongst groups. Data was analysed statistically using the same procedures as described for phase 1. The results of this trial clearly indicated that the scrotal fat deposits of rams previously fed on the He diet are mobilized (at least partially) during subsequent periods of moderate dietary energy restrictions without adverse effects on semen quantity and qua lity. This is the first time that such finding is reported. Further research on the effect of high energy diets on subsequent ram fertility (short and long terms), as well as their reversibility are warranted. Different age groups, feeding regimes and other management practices must also be associated to high energy diets in order to fully evaluate the effect of these common practices on subsequent ram fertility.

Genetic (co)variances for yearling body weight (BW), clean fleece weight (CFW) and mean fibre diameter (MFD) in the SA Dohne Merino population were estimated using records of 107 389 animals recorded between 1992 and 2004. The data include records of 1 530 sires and 45 178 dams. An animal model with direct and maternal additive, maternal permanent and temporary environmental effects was fitted for all traits. Sire-flock (SF) and sire-flock-year-season (SFYS) was included as additional random effects. Fixed effects were (FYSSM) (1594 classes), type of birth (singles, multiples), age of dam (2 to 7+ years) and average age (± SD) at measurement fitted as a linear covariate (385 ± 12 days). Estimates obtained by single -trait analyses were used as starting values in three-trait analyses. The direct genetic heritability estimates for FD, CFW and BW obtained from the three-trait analysis were 0.447 (0.009), 0.216 (0.008) and 0.277 (0.008) respectively. The genetic correlations were 0.050 between BW and CFW, 0.100 between BW and FD and 0.139 between FD and CFW. The phenotypic correlations were 0.318 between BW and CFW, 0.129 between BW and FD and 0.180 between FD and CFW. Direct genetic correlations of BW, CFW and MFD were positive, which suggest that selection for bigger and heavier sheep would generally lead to a stronger MFD and higher CFW. Because these values are very low the subsequent effect of this phenomenon would be that the effect of selection for body traits on fleece traits would be very small and vice versa. Genetic trends were calculated using the annual average breeding value estimates (EBV) for each trait. According to the genetic trends derived, the selection policy followed did cause genetic change in the traits studied, even though it was slow. The level of inbreeding (F) in the South African Dohne Merino sheep population is very low. The proportion of animals that was inbred to some extent increased from 0% (average F=0) in 1980 to 38% in 2003 (average F=1.22%). No significant inbreeding depression on BW, CFW and MFD could be found. In general the results suggest that inbreeding at present is not a serious problem in the South African Dohne Merino breed.