Management Tool For Populations Research Articles

Isolation of Microsatellite Markers and Analysis of Genetic Diversity Among East Atlantic Populations of the Sword Razor Shell Ensis siliqua: A Tool for Population Management

The sword razor shell Ensis siliqua (Linnaeus, 1758) is found mainly from Norway to the Atlantic coast of the Iberian Peninsula. It is intensively caught in Europe, being highly appreciated as seafood. To help in its conservation and management, five microsatellite markers were isolated and genetic variation was analyzed in samples from Ireland, Spain, and Portugal. The highly significant differentiation (θ = 0.287, P < 0.001) observed was mainly due to differences between samples from Irish and Iberian Peninsula localities, except Aveiro (its sample resembled the Irish samples, and it may be predominantly self-recruiting). These groups of samples showed significant differences in allelic richness that could be related to harvesting intensity. Moreover, microsatellites detected low but significant differentiation between Iberian localities (Celeiro and Olhão), and Aveiro differed significantly from Strangford Lough. Overall, results suggest that two independently evolving regions exist and that management strategies should be designed for each region.

How immunocontraception can contribute to elephant management in small, enclosed reserves: Munyawana population as a case study.

Immunocontraception has been widely used as a management tool to reduce population growth in captive as well as wild populations of various fauna. We model the use of an individual-based rotational immunocontraception plan on a wild elephant, Loxodonta africana, population and quantify the social and reproductive advantages of this method of implementation using adaptive management. The use of immunocontraception on an individual, rotational basis stretches the inter-calving interval for each individual female elephant to a management-determined interval, preventing exposing females to unlimited long-term immunocontraception use (which may have as yet undocumented negative effects). Such rotational immunocontraception can effectively lower population growth rates, age the population, and alter the age structure. Furthermore, such structured intervention can simulate natural process such as predation or episodic catastrophic events (e.g., drought), which regulates calf recruitment within an abnormally structured population. A rotational immunocontraception plan is a feasible and useful elephant population management tool, especially in a small, enclosed conservation area. Such approaches should be considered for other long-lived, social species in enclosed areas where the long-term consequences of consistent contraception may be unknown.

The Effects of Myxobolus cerebralis on the Physiological Performance of Whirling Disease Resistant and Susceptible Strains of Rainbow Trout

The development of rainbow trout Oncorhynchus mykiss strains that are resistant to whirling disease has shown promise as a management tool for populations in areas where Myxobolus cerebralis is present. However, the physiological effects of the disease on characteristics necessary for fish survival in natural river conditions have not been tested in many of these strains. Five rainbow trout strains were evaluated for their swimming ability and growth characteristics in relation to M. cerebralis exposure: the resistant German rainbow trout (GR) strain (Hofer strain), the susceptible Colorado River rainbow trout (CRR) strain, and three intermediate (hybrid) strains (F1 = GR x CRR; F2 = F1 x F1; B2 = backcross of F1 x CRR). Three broad response patterns among strain and exposure were evident in our study. First, exposure metrics, growth performance, and swimming ability differed among strains. Second, exposure to the parasite did not necessarily produce differences in growth or swimming ability. Exposure to M. cerebralis did not affect batch weight for any strain, and critical swimming velocity did not differ between exposed and unexposed families. Third, although exposure did not necessarily affect growth or swimming ability, individuals that exhibited clinical deformities did show reduced growth and swimming performance; fish with clinical deformities were significantly smaller and had lower critical swimming velocities than exposed fish without clinical deformities. Research and management have focused on GR x CRR hybrid strains; however, given the performance of the GR strain in our study, it should not be discounted as a potential broodstock. Additional field trials comparing the GR and F1 strains should be conducted before wholesale adoption of the GR strain to reestablish rainbow trout populations in Colorado.

HealthATM: Personal Health Cyberinfrastructure for Underserved Populations

There is an opportunity for personal health record (PHR) systems to play a vital role in fostering health self-management within underserved populations. If properly designed and promoted, it is possible that patients will use PHRs to become more empowered in taking an active role toward managing their health needs. This research examines the potential of a cyberinfrastructure-based PHR to encourage patient activation in health care, while also having population health implications. A multi-phased, iterative research approach was used to design and evaluate a PHR system called HealthATM, which utilizes services from a cloud computing environment. These services were integrated into an ATM-style interface aimed at providing a broad range of health consumers with the ability to manage health conditions and encourage accomplishment of health goals. Evaluation of the PHR included 115 patients who were clients of several free clinics in Los Angeles County. The majority of patients perceived ease of use (74%) and confidence (73%) in using the HealthATM system, and thought they would like to use it frequently (73%). Patients also indicated a belief in being responsible for their own health. However, fewer felt as though they were able to maintain necessary life changes to improve their health. Findings from the field tests suggest that PHRs can be a beneficial health management tool for underserved populations. In order for these types of tools to be effective within safety-net communities, they must be technically accessible and provide meaningful opportunities to increase patient engagement in their health care.

Noninvasive analysis of fecal reproductive hormone metabolites in female veiled chameleons (Chamaeleo calyptratus) by enzyme immunoassay

The noninvasive technique of gonadal steroid metabolite measurement in feces for evaluation of reproductive activity has proven an effective and important tool for population management in various captive species, but has not yet been validated and used in reptile species. In this study, enzyme immunoassays (EIAs) were validated for the analysis of fecal samples from female veiled chameleons (Chamaeleo calyptratus) for estrogen (E2), testosterone (T), and progesterone (P) and their metabolites. High performance liquid chromatography and physiological methods (GnRH stimulation) were used for the validation of the assays. Biological events, such as skin color changes indicative of ovarian activity and oviposition, correlated with the cyclical pattern of E2, T and P metabolites in feces over a period of two reproductive cycles. This is the first study to report frequent longitudinal measurements of fecal hormone levels by EIA in a reptile species.

Bioecology of the uçá-crab, Ucides cordatus (Linnaeus, 1763), in Vitória Bay, Espírito Santo State, Brazil

The biology of the Ucides cordatus in Vitória Bay (ES) was evaluated as a possible tool for population management. Sampling occurred monthly for about a year (October 1998 to September 1999) with biometric analysis (CW = carapace width; WW = total wet weight) and abiotic factors on four transects, each with four bands (margin to supratidal region). The density was 3.7±1.5 crabs.m-2 , with an increase toward the supratidal region, and depth of the galleries with 1.1 ± 0.3 m. The salinity of interstitial water differed between bands, being higher in the supratidal. There was significant correlation between the abundance of individuals and some environmental factors, the same occurring with open and closed burrows. The sex ratio showed a predominance of females (1.0M:1.6F), particularly between 50 and 75 mm (CW). The higher incidence of closed burrows occurred in August and September, while ovigerous females were recorded from January to April. The relationship WW/CW showed isometry for males (WW=0,425.10-3 LC3,0014; R²=0.99) and females (WW=0,439.10-3 LC2,97; R²=0.99). For the total population the average size (CW) and weight (WW) were 54.6±11.8 mm and 77.5±42.4 g, respectively. The population is under super-exploitation, requiring proper management for the viability of activity in the area.

Wild boar (Sus scrofa) harvesting using the espera hunting method: side effects and management implications

Harvesting of wildlife by man has been linked to demographic and evolutionary impacts in many populations. We investigated the sex ratio and age class structure in hunting bags of wild boar harvested by espera—nocturnal single hunt at bait—during four hunting seasons in Alentejo (Portugal). In addition, we assessed whether the hunting method is a significant predictor of the probability of harvesting an animal of a particular gender, of particular age class or of a particular combination of these two attributes. We found that the espera hunting method allows very selective harvesting regimes, and thus, it seems a highly effective population management tool. Removing a large proportion of adult males, however, may bias the population sex ratio towards females, reduce male life expectancy and raise the degree of polygyny. Our results suggest that recruitment rates are resilient to this skewed sex ratio, and possibly the higher proportion of females in the adult population may even increase productivity.

Contraceptive efficacy of a novel intrauterine device (IUD) in white-tailed deer

Overabundant white-tailed deer ( Odocoileus virginianus) pose risks to property, health, and safety of human beings. Public concerns about lethal management can impair efforts to address these issues, particularly in urban settings. Several techniques developed for reducing reproductive output of deer have limited utility because they require repeated dosing to achieve permanent effect and face uncertain regulatory approval for use beyond experimentation. From 10 August 2006 through 30 December 2007, we evaluated the contraceptive efficacy of copper-containing intrauterine devices (IUDs) implanted trans-cervically in white-tailed deer at the E.S. George Reserve in Pinckney, Michigan. Intrauterine devices were implanted before ( n = 9) and shortly after ( n = 10) the breeding season. Post-breeding season IUD treatment was in conjunction with a 5 cm 3 dose of 5 mg/ml prostaglandin F 2α (PGF 2α), delivered subcutaneously. Intrauterine devices reduced pregnancy rates when administered prior to breeding ( P < 0.001) and prevented pregnancy for up to 2 years (the duration of the study). Two of 8 does that received IUDs prior to the breeding season and survived to the end of the study became pregnant (due to loss of the implant) during the second year while all ( n = 16) does without implants conceived. Cervical changes associated with early pregnancy made trans-cervical implantation after the breeding season challenging, and resulted in improperly placed IUDs in 2 treated does. The apparent expulsion of IUDs by pregnant does that received the combined treatment after breeding suggests IUD treatment should be limited to the pre-breeding season. Intrauterine devices show potential as a tool for small-scale deer population management via non-steroidal reproductive inhibition.

Can Guideline Adherence Be Improved by Letter Outreach?

The Heart Protection Study established that statins are beneficial for most patients with diabetes regardless of baseline LDL cholesterol (1–2). Kaiser Permanente Colorado, a group-model, nonprofit health-maintenance organization in the Denver/Boulder metropolitan area, developed a letter-based population management strategy to improve statin utilization in patients with diabetes. Kaiser Permanente Colorado maintains a disease state registry of patient-specific data for members with validated diagnoses, which serves as an ideal tool for patient tracking, quality improvement, and population management. Although letters have previously been employed for population education purposes (3–5), no published literature describes their effectiveness at …

Population-level effects of immunocontraception in white-tailed deer (Odocoileus virginianus)

In North America, dense populations of white-tailed deer (Odocoileus virginianus) in suburbs, cities and towns have stimulated a search for new population-management tools. Most research on deer contraception has focused on the safety and efficacy of immunocontraceptive vaccines, but few studies have examined population-level effects. We report here results from two long-term studies of population effects of the porcine zona pellucida (PZP) immunocontraceptive vaccine, at the National Institute of Standards and Technology (NIST), Gaithersburg, Maryland, USA, and at Fire Island National Seashore (FIIS), New York, USA. Annual population change at NIST was strongly correlated with population fertility (rP = 0.82, P = 0.001); when population fertility at NIST dropped below 0.40 fawns per female, the population declined. Contraceptive treatments at NIST were associated with a 27% decline in population between 1997 and 2002, and fluctuated thereafter with the effectiveness of contraceptive treatments. In the most intensively treated segment of FIIS, deer population density declined by ~58% between 1997 and 2006. These studies demonstrate that, in principle, contraception can significantly reduce population size. Its usefulness as a management tool will depend on vaccine effectiveness, accessibility of deer for treatment, and site-specific birth, death, immigration, and emigration rates.

Spatial interactions and habitat use of rabbits on pasture and implications for the spread of rabbit haemorrhagic disease in New South Wales

Successful control of European rabbit (Oryctolagus cuniculus) populations in Australia has been achieved with the use of disease, initially myxomatosis and more recently rabbit haemorrhagic disease (RHD). Predicting the effectiveness of disease as a control agent depends on understanding the spatial and social organisation of its host population. We radio-tracked 37 rabbits from adjacent burrow systems during May and June 1999. Surface-dwelling rabbits had larger home ranges and core areas and a higher proportion of vegetation cover in their ranges than warren-based rabbits. Interactions between rabbit dyads from the same warren showed greater range overlap than those involving rabbits from different warrens and those involving itinerants. Static interaction was high and positive for intra-warren dyads, but low and negative for inter-warren, warren–surface and surface–surface dyads. These patterns of range use and interaction behaviour create a hierarchical contact and transmission structure within the rabbit population that is likely to vary according to external factors such as population density, resource availability, season, climate and the environment. Quantifying these links between the environment and the transmission process is important to increase our understanding of RHD as an effective management tool for rabbit populations.

Usefulness of Structural and Condition Indices in Management of High-Mountain Stream Salmonid Populations

Abstract We assessed the utility of relative weight (Wr ), young-to-adult ratio (YAR), and a stock density index (SDI) calculated in a manner similar to the proportional stock density index as management tools for populations of brook trout Salvelinus fontinalis in six high-elevation streams. On each stream, estimates were made for production, biomass, production: biomass ratio, and brook trout density, as well as 14 environmental variables. The SDI varied substantially among streams and was significantly related to mean depth and conductivity, but not to any other environmental variables or to any of the population parameters. Values of Wr varied substantially over the growing season and were inversely related to mean depth for fish 100–150 mm and more than 150 mm total length, and directly (but marginally) related to production: biomass ratio for medium (>150-mm) and large (>200-mm) fish. Estimates of YAR were related only to the production biomass ratio. Structural indices, in general, were correlated ...

Limitations of Male-Oriented Contraception for Controlling Feral Horse Populations

We developed a computer program to simulate key features of feral horse (Equus caballus) population dynamics and breeding cycles because of the continuing controversy over male- versus female-oriented contraceptive approaches to population management. We used the program to investigate the potential efficacy of male-oriented contraception as a population management tool, and to explore the impacts of such programs on the normal seasonal foaling pattern. The treatment strategies we tested included sterilizing only dominant harem stallions and sterilizing males without regard to their social status

Population Dynamics in Complex Landscapes: A Case Study.

The abundance and distribution of natural populations can be strongly influenced by the types and arrangement of habitat patches within a landscape. The impact of landscape changes on population dynamics is difficult to study using conventional population models and field techniques. Spatially explicit simulation models provide a powerful method for modelling landscape and population changes at large spatial scales and may prove useful as a management tool for mobile animal populations. As an example of this approach, we present a model designed to elucidate the effects of landscape-level variation in habitat dispersion on the size and extinction probability of avian populations in a region managed for timber production. In the model, habitat suitability and availability within the landscape change annually as a function of timber harvest and management strategies. The model incorporates life history characteristics of Bachman's Sparrow (Aimophila aestivalis), a species of management concern in the southeastern United States, and the landscape characteristics of the Savannah River Site, South Carolina, an area managed for timber production where the sparrow is relatively common. Life history characteristics used in the model include dispersal, survivorship, and reproductive success information reported for Bachman's Sparrow at this site or elsewhere in its range. Results of the simulations suggest that variation in demographic variables affects population size more than variation in dispersal ability. Changes in adult and juvenile survivorship have especially large impacts on the probability of population extinction. The presence of habitat types that serve as permanent sources of dispersers increases the total population size in the landscape, and lowers the probability of extinction. Results of models such as BACHMAP can suggest modifications to current management plans that would increase the probability of population persistence for species of special concern in managed landscapes.

Interaction Assessment II: A Tool for Population and Community Management

To successfully preserve or manage a species, we must understand how the community of which it is a part functions. We must know how environmental alterations affect the fitness not only of the species of interest, but also that of its competitors, predators, and prey; and we must know the form and intensity of the pertinent inter-species interactions. Interaction Assessment (INTASS) is a non-manipulative approach to constructing quantitative expressions for fitness, written as functions of measured environmental variables including local population densities of conspecifics and other interacting species. We applied this approach to, and evaluated its consistency from, data on the European land snail (Cepaea nemoralis), American eel (Anguilla rostrata), longnosed and blacknosed dace (Rhinichthys cataractae and R. atratulus), and small- mouth bass (Micropterus dolomieu) until data sets can be compiled on more typically studied vertebrates. INTASS analyses on key species of a community can provide the tools for predicting community-wide ramifications of environmental disturbances. They also can permit the planned manipulation of relative species abundances through habitat alteration.

Activity of Cyromazine on Onion Maggot Larvae (Diptera: Anthomyiidae) in the Soil

A laboratory bioassay technique with soil was developed to investigate the toxicity and activity of the insect growth regulator, cyromazine, to onion maggot larvae, Delia antique (Meigen) (Diptera: Anthomyiidae). LC50’s (ppm in soil) for chlorpyrifos, fonofos, and cyromazine were 8.4, 9.4, and 17.5, respectively. Significant mortality due to cyromazine treatment was observed at the time of molt between first and second instar (72 h). Surviving larvae in soil treated with cyromazine developed more slowly than larvae in untreated soil. At 144 h, > 90% mortality occurred in the cyromazine treated soil compared with <10% in untreated soil. Because it has a different mode of action than the currently registered insecticides, cyromazine may have potential as a management tool for resistant populations, or in a resistance management program. Cyromazine may also be effective in controlling other soil insects.

Fertility control as a management tool for feral horse populations

Technology for the humane regulation of feral horse populations is currently inadequate. The application of fertility control technology to feral horses may yield improved management capabilities. The present paper addresses the possibilities for fertility control in feral horses within the framework of characteristics of the ideal contraceptive. The pros and cons of various methodologies are given, with resultant selection of the preferred ones. A brief description of completed and current studies of feral horse fertility control is presented, with constructive critical analysis of each technique for males and females. Finally, projections are made for relative cost effectiveness of the most studied fertility control method in comparison with Adopt-A-Horse.

A Model for Optimization of Roe Deer Management in Central Europe

A Model for Optimization of Roe Deer Management in Central Europe