Home About us Contact
|
Home About us Contact | ||
|
|
||
Population Monitoring (population + monitoring)
Selected AbstractsMonitoring and management of the endangered Cape mountain zebra Equus zebra zebra in the Western Cape, South AfricaAFRICAN JOURNAL OF ECOLOGY, Issue 2 2008Rebecca K. Smith Abstract De Hoop Nature Reserve and a neighbouring conservancy contain the most genetically diverse subpopulation of the Endangered (IUCN) Cape mountain zebra (Equus zebra zebra Linnaeus 1758). Although vital for the long-term stability of the meta-population, the population had received limited monitoring post-1999. We summarize data obtained during a population monitoring programme established in 2005. Ninety-nine individuals were identified indicating a decline in annual population growth from 6.6% (1995,1999) to 4.5% (1999,2005). The population was male biased and the deficit of females is likely to have prevented additional breeding herd formation resulting in excess nonbreeding males. These animals are currently of limited reproductive value to the meta-population and may be contributing to the decline in reproductive potential at De Hoop by competing for limited resources. One solution may be to translocate ,excess' males to reinforce existing small populations or establish new populations with females from elsewhere provided that a minimum of 78 animals is maintained at De Hoop to limit genetic loss. Population monitoring and effective management strategies for the De Hoop population and the meta-population are vital to ensure the long-term survival of Cape mountain zebra and for the success of other species recovery programmes. Résumé De Hoop Nature Reserve et une aire de conservation voisine contiennent la sous-population la plus génétiquement variée du zèbre de montagne du Cap (Equus zebra zebra Linnaeus 1758), classé« en danger » par l'UICN. Bien que vitale pour la stabilitéà long terme de la métapopulation, cette population a été peu suivie depuis 1999. Nous avons résumé les données recueillies au cours d'un programme de monitoring de la population instauré en 2005. Quatre-vingt dix-neuf individus ont été identifiés, ce qui indique un déclin de la croissance annuelle de la population de 6,6% (1995,1999) à 4,5% (1999,2005). La population est biaisée en faveur des mâles, et c'est probablement le déficit en femelles qui a empêché la formation d'un troupeau reproducteur supplémentaire, qui a abouti à un excès de mâles nonreproducteurs. Ces animaux sont actuellement de peu de valeur de reproduction pour la métapopulation et pourraient contribuer au déclin du potentiel reproducteur à De Hoop par la compétition qu'ils représentent pour les ressources limitées.Une solution pourrait être de déplacer les mâles « en excès » pour renforcer les petites populations existantes ou pour en établir de nouvelles avec des femelles venues d'ailleurs, pour autant qu'un minimum de 78 animaux restent à De Hoop pour limiter l'appauvrissement génétique. Des stratégies pour le monitoring et la gestion efficace de la population de De Hoop sont vitales pour garantir la survie à long terme du zèbre de montagne du Cap et pour la réussite des programmes de restauration d'autres espèces. [source] Reduction in an almond moth Ephestia cautella (Lepidoptera: Pyralidae) population by means of mating disruptionPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 10 2006Camilla Ryne Abstract Pheromone-based mating disruption of the almond moth (Ephestia cautella) (Walk.) (Lepidoptera: Pyralidae) was carried out in a chocolate factory in Sweden. Population monitoring was conducted with pheromone-baited traps and water traps. Pheromone traps showed a 94% catch reduction, and monitoring with water traps showed a significant decrease in total catch (5.0 and 1.6 individuals per trap per week before and during treatment respectively). The significance of the results was tested by fitting the observed data to a first-order autoregressive model. This made it possible to test the data with a 95% confidence interval, comparing trap catches before mating disruption treatment with trapping data during the experiment. It is suggested that this statistical approach may be used more frequently in mating disruption experiments where it is extremely difficult to control external factors and therefore equally difficult to use a comparable control plot to evaluate the treatment. Copyright © 2006 Society of Chemical Industry [source] The Conservation Relevance of Epidemiological Research into Carnivore Viral Diseases in the SerengetiCONSERVATION BIOLOGY, Issue 3 2007SARAH CLEAVELAND conservación de carnívoros; investigación epidemiológica; moquillo; rabia; Serengeti Abstract:,Recent outbreaks of rabies and canine distemper in wildlife populations of the Serengeti show that infectious disease constitutes a significant cause of mortality that can result in regional extirpation of endangered species even within large, well-protected areas. Nevertheless, effective management of an infectious disease depends critically on understanding the epidemiological dynamics of the causative pathogen. Pathogens with short infection cycles cannot persist in small populations in the absence of a more permanent reservoir of infection. Development of appropriate interventions requires detailed data on transmission pathways between reservoirs and wildlife populations of conservation concern. Relevant data can be derived from long-term population monitoring, epidemic and case-surveillance patterns, genetic analyses of rapidly evolving pathogens, serological surveys, and intervention studies. We examined studies of carnivore diseases in the Serengeti. Epidemiological research contributes to wildlife conservation policy in terms of management of endangered populations and the integration of wildlife conservation with public health interventions. Long-term, integrative, cross-species research is essential for formulation of effective policy for disease control and optimization of ecosystem health. Resumen:,Brotes recientes de rabia y moquillo en poblaciones silvestres del Serengeti muestran que las enfermedades infecciosas constituyen una causa significativa de mortandad que puede resultar en la extirpación regional de especies en peligro, aun en áreas extensas bien protegidas. Sin embargo, el manejo efectivo de una enfermedad infecciosa depende críticamente del entendimiento de la dinámica epidemiológica del patógeno. Los patógenos con ciclo infeccioso corto no pueden persistir en poblaciones pequeñas en ausencia de un reservorio de la infección más permanente. El desarrollo de intervenciones adecuadas requiere de datos detallados de las vías de transmisión entre reservorios y poblaciones de vida silvestre de preocupación para la conservación. Se pueden derivar datos importantes del monitoreo de poblaciones a largo plazo, de patrones de epidemias y de estudios de caso, del análisis genético de patógenos que evolucionan rápidamente, de muestreos sexológicos y de estudios de intervención. Examinamos estudios de enfermedades de carnívoros en el Serengeti. La investigación epidemiológica contribuye a las políticas de conservación de vida silvestre en términos de la gestión de poblaciones en peligro y de la integración de la conservación con intervenciones de salud pública. La investigación a largo plazo e integradora es esencial para la formulación de políticas efectivas para el control de enfermedades y la optimización de la salud del ecosistema. [source] A practical method for predicting the short-time trend of bivoltine populations of Ips typographus (L.) (Col., Scolytidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 1 2006M. Faccoli Abstract:,Ips typographus is the main spruce pest of European forests. In most areas of the Italian Alps there are two generations per year; overwintering adults fly in May looking for trees suitable for breeding, their offspring emerge in summer, 7,8 weeks after tree colonization, and the adults of the second generation emerge in spring of the following year after overwintering under the bark or in the litter. A long-term population monitoring was carried out in north-east Italy with the aim at developing a prediction model able to estimate the population density of the following year. Between 1996 and 2004, pheromone traps monitored populations of I. typographus annually. Monitoring lasted 4 months (May,August), with replacement of pheromone dispensers after 8 weeks. Insects trapped before dispenser change were called ,spring captures' (May,June), and included both overwintering and re-emerging adults. Beetles caught after dispenser change were called ,summer captures' (July,August), and included the adults of the first generation. The results show a high positive correlation between the ratio of summer and spring captures of one year (Summerx/Springx), and the ratio of total captures of the following year (Yx+1) and those of the current year (Yx) (Yx+1/Yx). Summerx/Springx lower than 0.62 indicate decreasing populations in the following year (Yx+1/Yx <1), whereas Summerx/Springx higher than 0.62 indicate increasing populations (Yx+1/Yx >1). The applicability of the model in the study of I. typographus risk of outbreak and in the forest management is discussed. The prediction of the short-time trend of the population allows assessing its density in the following year, and therefore the risk of outbreak. [source] Population trends and habitat use of Harlequin Ducks in Rhode IslandJOURNAL OF FIELD ORNITHOLOGY, Issue 3 2007Christine M. Caron ABSTRACT To assess population trends of Harlequin Ducks (Histrionicus histrionicus) in Rhode Island (U.S.A.), we analyzed Christmas Bird Counts and other historical surveys and also conducted surveys during the winter of 2005,2006. We estimated sex and age ratios, evaluated the effects of tidal regime and time of day on survey precision, and quantified habitat use. The population in Rhode Island experienced logistic growth from 1976 to 2004, with approximately 150 birds now wintering at three primary sites in the state. We estimated that the current ratio of males to females in the region was 1.6:1 (62% males) and that 13% of males were first-winter birds. Most Harlequin Ducks were observed in rocky habitats within 50 m of the shore or offshore islands. We detected the greatest numbers of birds, with the least amount of variation, during morning surveys at low tide, suggesting that this may be the most appropriate time for population monitoring. Increases in the Rhode Island population and male-biased sex ratios may indicate a local population recovery resulting from a hunting ban initiated in 1990. Although most Harlequin Ducks in eastern North America winter in Maine, the population in Rhode Island represents one of the largest in the southern part of their range. SINOPSIS Para determinar las tendencias poblacionales de arlequines (Histrionicus histrionicus), en Rhode Island, analizamos los conteos navideños, otros censos históricos y además llevamos a cabos censos durante el invierno de 2005,2006. Cuantificamos el uso de habitat, estimamos la tasa de edad y sexos y evaluamos el efecto del régimen de mareas y la hora del dia en la presición de los censos. La población de patos arlequines experimentó un crecimiento logístico de 1976,2004, con unos 150 patos pasando el invierno en tres localidades primarias, del estado. Estimamos una tasa de 1.6:1 de machos a hembras (62% de machos), siendo un 13% de los machos individuos de primer invierno. La mayoría de las aves fueron observadas en hábitats rocosos a unos 50 m de la playa o en islas cerca de la playa. Detectamos el mayor número de aves, con la menor variación, en los censos que se llevaron a cabo durante la marea baja, lo que sugiere que este es el momento más apropiado para monitorear sus poblaciones. El aumento de estas aves en Rhode Island, el sesgo en su sexo, hacia mayor cantidad de machos, pudiera indicar, de un recobro poblacional como resultado la prohibición de su cacería a partir de 1990. Aunque la mayoría de los arlequines de la parte este de los EUA pasan el invierno en Maine, la población de Rhode Island representa una de las mayores en la parte sur de su distribución. [source] Effect of varying monoterpene concentrations on the response of Ips pini (Coleoptera: Scolytidae) to its aggregation pheromone: implications for pest management and ecology of bark beetlesAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2003Nadir Erbilgin Abstract 1,Host plant terpenes can influence attraction of conifer bark beetles to their aggregation pheromones: both synergistic and inhibitory compounds have been reported. However, we know little about how varying concentrations of individual monoterpenes affect responses. 2,We tested a gradient of ratios of ,-pinene, the predominant monoterpene in host pines in the Great Lakes region of North America, to Ips pini's pheromone, racemic ipsdienol plus lanierone. 3,Ips pini demonstrated a parabolic response, in which low concentrations of ,-pinene had no effect on attraction to its pheromone, intermediate concentrations were synergistic and high concentrations were inhibitory. These results suggest optimal release rates for population monitoring and suppression programmes. 4,Inhibition of bark beetle attraction to pheromones may be an important component of conifer defences. At terpene to pheromone ratios emulating emissions from trees actively responding to a first attack, arrival of flying beetles was low. This may constitute an additional defensive role of terpenes, which are also toxic to bark beetles at high concentrations. 5,Reduced attraction to a low ratio of ,-pinene to pheromone, as occurs when colonization densities become high and the tree's resin is largely depleted, might reflect a mechanism for preventing excessive crowding. 6,Thanasimus dubius, the predominant predator of I. pini, was also attracted to ipsdienol plus lanierone, but its response differed from that of its prey. Attraction increased across all concentrations of ,-pinene. This indicates that separate lures are needed to sample both predators and bark beetles effectively. It also provides an opportunity for maximizing pest removal while reducing adverse effects on beneficial species. This disparity further illustrates the complexity confronting natural enemies that track chemical signals to locate herbivores. [source] The history and control of the pine beauty moth, Panolis flammea (D. & S.) (Lepidoptera: Noctuidae), in Scotland from 1976 to 2000AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2001B. J. Hicks Abstract 1,The pine beauty moth, Panolis flammea, has been a serious pest of lodgepole pine plantations in Scotland since 1976. It historically feeds on native Scots pine throughout Europe but population levels of P. flammea on this host have never been high enough to cause tree mortality in the U.K. 2,This paper reviews recent advances in the biology of the pest and documents control programmes from 1976 to 1999. 3,There has been practically uninterrupted population monitoring of P. flammea from 1977 to the present day in Scottish lodgepole pine plantations. Intervention with chemical spraying has often been necessary. 4,The population data suggest that populations of P. flammea may have had a cyclic pattern over the monitoring period, with outbreaks occurring at regular intervals of between 6 and 7 years. 5,The amplitude of population cycles was large during the 1970s and 1980s, but has dampened in recent years. Natural enemies are believed to contribute to this trend. Fungal disease, specifically, appears to have had a greater effect on pest populations in recent years than in the past and is suggested to have contributed significantly to the population dynamics observed since 1990. [source] Rarity and decline in palaeoendemic Martino's vole Dinaromys bogdanoviMAMMAL REVIEW, Issue 4 2008BORIS KRY, TUFEK ABSTRACT 1Martino's vole Dinaromys bogdanovi is the only living member of the Tertiary genus Dinaromys, and probably also the only surviving member of the Pliomys lineage. The range of the genus Dinaromys has historically been small and its rate of evolution has been low. 2Martino's vole shows all three attributes of rarity in accordance with Rabinowitz's ,seven forms of rarity' model: (i) its range is estimated at 43 545 km2 but the area of occupancy is <5200 km2; (ii) its habitat requirements are narrow and the species is strictly tied to exposed, karstified bedrock; and (iii) current populations are invariably small and frequently isolated. 3The Pleistocene range of Martino's vole exceeded the recent one, at least in the north-western part of the Balkans, and its shrinkage continued into the Holocene. 4Martino's vole may be in competition with the European snow vole Chionomys nivalis, which has a very similar morphology and presumably identical habitat requirements, but is shifted towards an r-selected life-history strategy. Long-term sympatry of these voles has probably resulted in competitive exclusion of the relatively K-selected Martino's vole by the relatively r-selected European snow vole. 5Martino's vole consists of two deeply divergent (about one million years ago) phylogeographical lineages, which may represent distinct cryptic species. Rarity is particularly pronounced in the north-western lineage to the west of the Neretva River, where rocky habitats are largely occupied by the European snow vole. 6In the IUCN Red List of Threatened Animals, Martino's vole is classified as ,near threatened'. However, the north-western lineage, which is phylogeographically most divergent and has the greatest genetic diversity, is classed as a ,vulnerable' evolutionary significant unit on the basis of its small area of occupancy (<2000 km2). Long-term population monitoring is an essential step in evaluating the conservation needs of Martino's vole. [source] SNPs in ecological and conservation studies: a test in the Scandinavian wolf populationMOLECULAR ECOLOGY, Issue 2 2005J. M. SEDDON Abstract Single nucleotide polymorphisms (SNPs) have the potential to become the genetic marker of choice in studies of the ecology and conservation of natural populations because of their capacity to access variability across the genome. In this study, we provide one of the first demonstrations of SNP discovery in a wild population in order to address typical issues of importance in ecology and conservation in the recolonized Scandinavian and neighbouring Finnish wolf Canis lupus populations. Using end sequence from BAC (bacterial artificial chromosome) clones specific for dogs, we designed assays for 24 SNP loci, 20 sites of which had previously been shown to be polymorphic in domestic dogs and four sites were newly identified as polymorphic in wolves. Of the 24 assayed loci, 22 SNPs were found to be variable within the Scandinavian population and, importantly, these were able to distinguish individual wolves from one another (unbiased probability of identity of 4.33 × 10,8), providing equivalent results to that derived from 12 variable microsatellites genotyped in the same population. An assignment test shows differentiation between the Scandinavian and neighbouring Finnish wolf populations, although not all known immigrants are accurately identified. An exploration of the misclassification rates in the identification of relationships shows that neither 22 SNP nor 20 microsatellite loci are able to discriminate across single order relationships. Despite the remaining obstacle of SNP discovery in nonmodel organisms, the use of SNPs in ecological and conservation studies is encouraged by the advent of large scale screening methods. Furthermore, the ability to amplify extremely small fragments makes SNPs of particular use for population monitoring, where faecal and other noninvasive samples are routinely used. [source] Assessing levels of contaminants in breast milk: methodological issues and a framework for future researchPAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 1 2008Mary J. Renfrew Summary To assess the scale of the possible exposure by the breast-fed infant to potentially harmful substances in breast milk, methodologically robust studies are essential. Many studies in this field, however, do not report details of crucial issues such as recruitment and milk sampling. The aims of the study reported here were to develop robust methods for the study of contaminants in breast milk, and to develop a framework for future research and population monitoring. Three cohorts of women and babies were recruited by midwives from five sites in northern England. Cohort 1 (cross-sectional, n = 322) were asked to provide two milk samples, one at one week following birth and one at a subsequent time point. Cohort 2 (longitudinal, n = 54) were asked to provide five samples at specified time points over the first 12,16 weeks after birth. Cohort 3 (convenience, n = 18), mothers of babies in the Special Care Unit, were asked to donate surplus breast milk. A novel method of analysing fat concentration in small volumes was developed and tested. A randomly selected set of samples from different donors and stages of lactation was screened for organochlorine pesticide residues, polychlorinated biphenyls, dioxins/furans, phthalates and heavy metals. A total of 453 samples were donated. Cohort 3 was the least successful route of recruitment. Cohorts 1 and 2 combined were most representative of the population. Sample collection, transport and storage procedures, and the collection of data on life style and diet, were robust and acceptable to women. Midwifery involvement in recruitment was an essential component. This study offers a framework both for the conduct of future research studies, and for the establishment of regional and national monitoring mechanisms for contaminants in breast milk. Similar work on contaminants in formula as fed to babies is needed to inform risk assessment methods. [source] Distribution modelling to guide stream fish conservation: an example using the mountain sucker in the Black Hills National Forest, USAAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2008Daniel C. Dauwalter Abstract 1.Conservation biologists need tools that can utilize existing data to identify areas with the appropriate habitat for species of conservation concern. Regression models that predict suitable habitat from geospatial data are such a tool. Multiple logistic regression models developed from existing geospatial data were used to identify large-scale stream characteristics associated with the occurrence of mountain suckers (Catostomus platyrhynchus), a species of conservation concern, in the Black Hills National Forest, South Dakota and Wyoming, USA. 2.Stream permanence, stream slope, stream order, and elevation interacted in complex ways to influence the occurrence of mountain suckers. Mountain suckers were more likely to be present in perennial streams, and in larger, higher gradient streams at higher elevations but in smaller, lower gradient streams at lower elevations. 3.Applying the logistic regression model to all streams provided a way to identify streams in the Black Hills National Forest most likely to have mountain suckers present. These types of models and predictions can be used to prioritize areas that should be surveyed to locate additional populations, identify stream segments within catchments for population monitoring, aid managers in assessing whether proposed forest management will potentially have impacts on fish populations, and identify streams most suitable for stream rehabilitation and conservation or translocation efforts. 4.When the effect of large brown trout (Salmo trutta) was added to the best model of abiotic factors, it had a negative effect on the occurrence of mountain suckers. Negative effects of brown trout on the mountain sucker suggest that management of recreational trout fisheries needs to be balanced with mountain sucker conservation in the Black Hills. However, more spatially explicit information on brown trout abundance would allow managers to understand where the two species interact and where recreational fisheries need to be balanced with fish conservation. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||