ABSTRACT
Habitat fragmentation can lead to a decline of genetic diversity, a potential risk for the survival of natural populations. Fragmented populations can become highly differentiated due to reduced gene flow and genetic drift. A decline in number of individuals can result in lower reproductive fitness due to inbreeding effects. We investigated genetic variation within and between 11 populations of the rare and endangered plant Silene chlorantha in northeastern Germany to support conservation strategies. Genetic diversity was evaluated using AFLP techniques and the results were correlated to fitness traits. Fitness evaluation in nature and in a common garden approach was conducted. Our analysis revealed population differentiation was high and within population genetic diversity was intermediate. A clear population structure was supported by a Bayesian approach, AMOVA and neighbour-joining analysis. No correlation between genetic and geographic distance was found. Our results indicate that patterns of population differentiation were mainly caused by temporal and/or spatial isolation and genetic drift. The fitness evaluation revealed that pollinator limitation and habitat quality seem, at present, to be more important to reproductive fitness than genetic diversity by itself. Populations of S. chlorantha with low genetic diversity have the potential to increase in individual number if habitat conditions improve. This was detected in a single large population in the investigation area, which was formerly affected by bottleneck effects.
Subject(s)
Ecosystem , Endangered Species , Genetic Fitness , Genetic Variation , Genetics, Population , Silene/genetics , Conservation of Natural Resources , Gene Flow , Genetic Drift , Germany , PollinationABSTRACT
The psychometric properties of the Civilian Mississippi Posttraumatic Stress Disorder (PTSD) Scale were explored. The Mississippi is internally consistent (alpha approximately = .89, split-half r approximately = .80), and it can discriminate between traumatized and nontraumatized respondents. However, its relationship with measures of PTSD was weaker than its relationship with measures of depression and anxiety, suggesting that it may be more of a general measure of distress. The results of a series confirmatory factor analyses provided mixed results. These findings were discussed along with recommendations for use of this instrument.
Subject(s)
Personality Inventory/statistics & numerical data , Stress Disorders, Post-Traumatic/diagnosis , Adult , Anxiety/diagnosis , Anxiety/psychology , Depression/diagnosis , Depression/psychology , Diagnosis, Differential , Female , Humans , Life Change Events , Male , Psychometrics , Reference Values , Reproducibility of Results , Stress Disorders, Post-Traumatic/psychology , Students/psychologyABSTRACT
The lifetime prevalence of traumatic events and their psychological impact were assessed in 440 undergraduate students. Eighty-four percent of the subjects reported experiencing at least one event of sufficient intensity potentially to elicit Post-Traumatic Stress Disorder (PTSD). One-third of the sample had experienced four or more traumatic events. Subjects who had experienced trauma reported higher levels of depression, anxiety, and PTSD symptomatology than nontraumatized subjects, and these symptoms were more intense in subjects who experienced multiple traumas. Events that were particularly negative in their impact included unwanted sexual experiences and events that subjects reported were too traumatic to discuss openly. Males and females differed in their probability of experiencing some types of events and in the psychological response to certain events.