Forensic investigators encountering remains deposited in an outdoor environment face many obstacles, including the scavenging, scattering, and reconcentration of remains by local vertebrate fauna. Scattering rates can vary considerably from region to region, and are highly dependent on the indigenous scavengers present (Haglund et al. 1988; Haglund et al. 1989; Mann et al. 1990; Morton and Lord 2006). In turn, scavenger activity is highly dependent on seasonal changes, rainfall, temperature fluctuations, and environmental stressors such as seasonal resource availability and dietary changes (Brown et al. 2006; Mann et al. 1990; O’Brien et al. 2007). A more thorough knowledge of the variation in scavenging and scattering patterns of the indigenous fauna in different geographical regions would produce a more productive search pattern and increase the recovery rate of scattered remains for those involved in outdoor crime scene investigations. The current study followed and documented the behavior of the indigenous carnivorous birds and mammals, as well as the scattering patterns of these species, in Eastern Massachusetts, using five porcine (Sus scrofa) carcasses. Carcasses were deposited in lightly wooded environments under different depositional settings and tracked by low-light wildlife video cameras and radio transmitter tags attached to the long bones of some of the limbs. The major scavengers of decomposing remains were documented, and the distance and direction of scattered skeletal elements were noted, as well as any secondary depositions. This research was conducted in three phases; the first was a preliminary observation of faunal wildlife and their distribution during the early summer of 2011, followed by one 14-week observation of porcine models during midsummer of 2011 and one 6-week observation of porcine models during late summer and early fall of 2011. Results show that seasonality greatly affects scavenging activity, as carrion deposited in the summer are primarily consumed by the indigenous invertebrate community, causing accelerated decomposition and vertebrate scavenger exclusion. Additionally, though marsupials and avian species fed the longest, coyotes (Canis latrans) produced the most destructive dispersal of carrion. Moreover, although coyotes disarticulated carcasses relatively nearby the original deposition, they sought out outdoor environments that are mostly devoid of human activity to feed upon disarticulated assemblages.

Thesis (M.A.)--Texas State University-San Marcos, 2008. / Vita. Appendices: leaves 74-79. Includes bibliographical references (leaves 80-84). Also available on microfilm.

Roads cause substantial wildlife mortality, but there is currently limited understanding of the relative magnitude of this mortality source. There are also substantial gaps in knowledge concerning the ecological ramifications of carrion introduced to the environment from vehicle collisions and in particular how vertebrate scavengers may consume carrion resulting from vehicle collisions. Although a variety of factors influence scavenger use of carcasses, the mechanisms influencing competition for this resource between obligate and facultative scavengers have not been thoroughly explored. I conducted a global synthesis of mortality of terrestrial vertebrates documenting 42,755 mortalities of known cause from 120,657 individuals representing 305 vertebrate species. Overall, 28% of mortalities were directly caused by humans and 72% were from natural sources. Vehicle collisions accounted for 4% of mortality overall. Larger birds were more likely than smaller birds to die from vehicle collisions and vehicle mortality of mammals increased over time. There was no difference in proportion of rabbit carcasses scavenged or scavenger arrival time between those placed along roads, power line clearings, and forests. No species arrived at roads quicker than other treatments. Turkey vultures (Cathartes aura) and coyotes (Canis latrans) scavenged equally across treatments, whereas gray foxes (Urocyon cinereoargenteus) scavenged along roads and power lines, but not in forests. Scavenger use of carrion near roads likely relates to factors besides carrion availability, such as traffic avoidance and predation risk. Because some scavengers make substantial use of carrion on roads, this resource could be an important mechanism by which human activities impact wildlife. Scavenging by facultative scavengers did not increase in the absence of competition with vultures. I found no difference in scavenger presence between control carcasses and those from which vultures were excluded. Facultative scavengers did not functionally replace vultures during summer in this study. These results suggest that under the conditions of this study, facultative scavengers would not compensate for loss of vultures. Carcasses would persist longer in the environment and consumption of carrion would likely shift from vertebrates to decomposers. Such changes could have substantial implications for disease transmission, nutrient cycling, and ecosystem functioning.

No description available.

Cyclolinopeptides (CLs) are hydrophobic cyclic peptides found in flaxseed. They show immunosuppressive activity, but the biological function of these compounds is largely unknown. This thesis presents the results of studies that were conducted to determine whether CLs could act as antioxidants. In the first study, flaxseed oil was passed over a silica adsorbent column to remove polar compounds. The polar compounds were then eluted from the silica absorbant using a series of increasingly polar solvents. Individual polar fractions were then added back to the silica-treated flaxseed oil and the oxidative stability index of these samples was determined at 100 °C. A polar fraction containing mainly CLA, β/γ- and δ-tocopherol increased the induction time of silica-treated flaxseed oil from 2.3 ± 0.28 h to 3.2 ± 0.41 h. A positive effect of the polar fraction containing a mixture of CLA and CLD-CLG on the oxidative stability of oil was also observed. The antioxidant mechanism of CLs was investigated in several model systems using electron spin resonance spectroscopy. The concentration of radicals in a DMPO (5,5-dimethyl-1-pyrroline-N-oxide) radical-CLs reaction mixture was monitored. All CLs exhibited dose dependent scavenging activities. CLA–CLC reactions with DMPO-OH at a concentration of 5 mM resulted in a 24–30% decrease in electron paramagnetic resonance (EPR) signal intensity. The reaction of CLs and the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) revealed a more complex interaction than simple radical scavenging. Peptides (CLG and CLG") that contained both tryptophan and methionine showed stronger radical scavenging activity than did CLs containing methionine or methionine sulfoxide but not tryptophan (CLB and CLC). Irradiation of the reaction mixture of DPPH• and peptide with UV light also affected the radical scavenging behaviour. Scavenging activities of DPPH• by CLB, CLC and CLA were enhanced by light, whereas scavenging of DPPH• by the tryptophan containing peptides CLG and CLG″ was not affected. High-performance liquid chromatography with mass spectrometry (HPLC-MS) analysis of the reaction mixtures after a radical scavenging reaction was used to determine the impact of radical scavenging on the peptides. These reactions revealed new masses that were identified and characterized. It was established that DPPH• reacted with the methionine of CLB and with tryptophan in CLG and CLG, by formation of a new covalently-bonded species. Covalent linkages between these amino acids (alone or in peptides) and DPPH• have not been reported previously.

No description available.

Mass mortality events (MMEs) are die-offs that result in increased carrion biomass and sometimes the impairment of functional roles. Concurrently, several vulture species are declining. Carrion is a basal resource in ecosystems and its recycling by vultures is considered an ecosystem service. However, the consequences of simultaneously increasing carrion loads and declining vulture populations are unknown. I developed a theoretical framework predicting that, with increasing carrion biomass, carrion food web diversity would increase horizontally and vertically, respectively increasing and decreasing carrion recycling efficiency. Using a manipulative experiment, I investigated the role of bottom-up and top-down forces affecting plant communities during an MME. I selected 5 sites to establish 6 treatments crossing different levels of carrion addition and nutrient addition, and control with vertebrate scavenger and herbivore access. I transplanted six cherrybark oak (Quercus pagoda) seedlings to each plot, protecting half of them from herbivory. Carrion biomass shifted dominance of plant functional groups to favor annual plants, an effect reduced by scavenger access. Herbivore access affected plant community response to carrion and limited growth and survival of transplanted seedlings regardless of treatment. Nutrient addition did not affect plant communities, growth, and survival suggesting that MME effects on plants are likely mediated primarily by top-down forces. To determine if behavioral plasticity of vultures affects carrion recycling efficiency, I monitored turkey (Cathartes aura) and black (Coragyps atratus) vulture behavior. Both species increased group size, but only black vultures increased individuals feeding per group and activity overlap between species increased with increasing carrion biomass. As a result, estimated carrion consumption by vultures increased with carrion biomass suggesting behavioral plasticity may alleviate some of the effects of vulture declines on carrion recycling. Finally, vultures compete with invertebrate scavengers so declining vultures may release their populations to compensate for the loss. However, in one of my experiments, variation in vulture visitation was negatively correlated with the abundance of blowflies parasitized by Entomophthora sp. Our observations may suggest that vultures were more likely mediating carrion decomposition affecting parasitism, which may limit blowflies from compensating for declining vultures.

Scavenging bird of prey have been abundant throughout the Mediterranean region for years, establishing a food acquisition relationship with human activities, their characteristics make them especially suitable for the recognition of dangerous environmental conditions. The West Nile Virus (WNV) considered the most widespread arbovirus has been previously discovered in our 3 species of studio. The analyses from feather follicles and serum samples obtain from different regions in Spain shown a higher seroprevalence against West Nile virus or cross-reacting flaviviruses in the northern part of the country and in the Canary archipelago. Our results showed a general seroprevalence of 19.8% (34 out of 172), a prevalence of 19,8% in Egyptian vultures, a prevalence of 27.1% (13 out of 48) in Griffon vultures and no prevalence in Cinereous vultures. Differences were observed for the body condition off Griffon and Egyptian vultures when anthropized and not anthropized areas were compared, being significantly worse in anthropized areas for Griffon vultures and significantly better for Egyptian vultures. The exposure to the virus of the nestlings increased with the age, showing a higher tend in Egyptian vultures than in Griffon vultures. Our results confirm the circulation and a higher seroprevalence of West Nile virus or cross-reacting flaviviruses than in previous studies.

[Truncated abstract] One of the standard ways of assessing time since death is from the stages of decomposition of the body. It is well known that the rate of decomposition is affected by environmental factors such as temperature and humidity. Another factor that can affect decompositional rates is the presence of breaches in the protective barrier of the skin, whether arising from antemortem injury or postmortem damage, including that occurring from animal necrophagy. Scavengers have the potential to affect decomposition by breaching the skin allowing access to associated insect material, feeding on the maggot masses, or by consumption of the carcass itself. Each locality will have its own set of features determining the rate of decomposition of the body, and variation may occur within localities based on the seasons. Such variation implies the need for local calibration of time since death against degree of decomposition and to establish the magnitude of interseasonal variation. When the localities are outdoors, the influence of potential scavengers, and the factors affecting their activity need also to be taken into account. This study investigates the interaction of environmental factors and animal scavenging on the rate of decomposition of pig (Sus scrofa) carcasses at four south-west Western Australia sites; Jandakot, Shenton Park, Perup Forest, and Watheroo National Park. Jandakot and Shenton Park are both close to the Perth metropolitan area and the western coast while Perup Forest is southern and inland and Watheroo is northern and inland. ... The most common insectivore feeding in relation to the carcasses was the Willie Wagtail (Rhipidura leucophrys) which was associated with the carcasses in all seasons and all locations except for Perup Forest. The breeding cycle appeared to have a marked influence on the intensity of scavenging by several species. The effect of season on decompositional rates was greatly reduced in carcasses that were exposed to scavenging. It took no additional time for carcasses to achieve skeletonization in winter than in the other seasons in the presence of scavenging. Scavenging had no significant impact on the rate of breakdown of carcasses in summer, when decompositional rates were greatest and scavenging at a minimum. v In Western Australia, it is not uncommon for bodies to remain undiscovered in bush environments for lengthy periods of time due to the low human population density. This study shows conclusively that it is not sufficient simply to consider the accumulated degree day (ADD) when estimating time since death by the degree of decomposition of the body. Attention must also be given to local wildlife assemblages and variations in their activities with the seasons. The implications of this research are in the determination of time of death. If the effects of scavengers accelerate decomposition this must be taken into account when any calculation since time of death is determined. The marked variations between sites in the rates of decomposition of carcasses exposed to natural animal scavenging in this study highlights the need for local calibration of time since death to decompositional stages for all locales. The techniques devised in this study are straight forward and easily conducted yet are informative and essential in determining time since death for bodies which have been exposed to animal scavenging.

Oxygen scavengers are used in active packages to protect the food against deteriorative oxidation processes. The aim of this work was to investigate the possibilities to produce oxygen-scavenging packaging materials based on oxygen-reducing enzymes. The enzymes were incorporated into a dispersion coating formulation applied onto a food-packaging board using conventional laboratory coating techniques. Various enzymes were used: a glucose oxidase, an oxalate oxidase and three laccases originating from different organisms. All of the enzymes were successfully incorporated into a coating layer and could be reactivated after drying. For at least two of the enzymes, re-activation was possible not only by using liquid water but also by using water vapour. Re-activation of the glucose oxidase and a laccase required relative humidities of greater than 75% and greater than 92%, respectively. Catalytic reduction of oxygen gas by glucose oxidase was promoted by creating an open structure through addition of clay to the coating at a level above the critical pigment volume concentration. Migration of the enzyme and the substrate was reduced by adding an extrusion-coated liner of polypropylene on top of the coating. For the laccase-catalysed reduction of oxygen it was possible to use lignin derivatives as substrates for the enzymatic reaction. The laccase-catalysed reaction created a polymeric network by cross-linking of lignin-based entities, which resulted in increased stiffness and increased water-resistance of biopolymer films. The laccases were also investigated with regard to their potential to function as oxygen scavengers at low temperatures. At 7°C all three laccases retained more than 20% of the activity they had at room temperature (25°C), which suggests that the system is also useful for packaging of refrigerated food.