|
| ||
|
|
||
Butterfly Abundance (butterfly + abundance)
Selected AbstractsSurvival, movement, and resource use of the butterfly Parnassius clodiusECOLOGICAL ENTOMOLOGY, Issue 2 2004Julia N. Auckland Abstract., 1. A mark,recapture study was conducted on the American Apollo butterfly Parnassius clodius Menetries during three field seasons (1998,2000) to examine its movement patterns over the course of a season within a sagebrush meadow in Grand Teton National Park, Wyoming, U.S.A. The study examined how resources affected butterfly distribution patterns and used mark,recapture data to gain insight into movement differences between sexes and over time. 2. The average straight-line movement of P. clodius was 202 m day,1, adjusted for sampling effort at different distances. Movement estimates in all 3 years were highly correlated with the average distance between plots sampled. 3. Butterfly abundance was correlated positively with per cent cover of its host plant Dicentra uniflora, but this relationship decreased in importance during the peak of the flight period when individuals may be more interested in finding mates. There was a weak, positive correlation between butterfly abundance and the abundance of its primary nectar source, Eriogonum umbellatum in 1999, but no relationship in 2000. 4. Survival, recapture, and transition probabilities were estimated using open population, capture,recapture models. Survival and recapture probability decreased over the course of each season, while the probability of moving between plots increased. Recapture probability was significantly lower for females than for males among all 3 years, but there was no difference between the sexes in survival rate. [source] Asymmetric dispersal and survival indicate population sources for grassland butterflies in agricultural landscapesECOGRAPHY, Issue 2 2007Erik Öckinger We tested the hypothesis that populations in small habitat fragments remaining in agricultural landscapes are maintained by repeated immigration, using three grassland butterflies (Aphantopus hyperantus, Coenonympha pamphilus and Maniola jurtina). Transect counts in 12 matched sets of semi-natural pastures, and linear habitat elements proximate and isolated from the pastures showed that population densities of M.,jurtina and C.,pamphilus were significantly higher in pastures and in linear habitats adjacent to these than in isolated linear elements. A mark-recapture study in a 2×2 km landscape indicated that individuals of all three species are able to reach even the isolated linear elements situated at least 1 km from the grasslands. For two of the species, A.,hyperantus and C.,pamphilus, analysis of the mark-recapture data revealed higher daily local survival rates in the semi-natural pastures and more individuals dispersing from pastures to linear habitat elements. The proportion of old compared to young individuals of C.,pamphilus and M.,jurtina were significantly higher in linear elements than in semi-natural pastures, which suggests that butterflies emerging in pastures subsequently dispersed to the linear elements. In combination, these results suggest that semi-natural pastures act as population sources, from which adult butterflies disperse to surrounding linear elements. Hence, preservation of the remaining fragments of semi-natural grassland is necessary to keep the present butterfly abundance in the surrounding agricultural landscape. [source] Survival, movement, and resource use of the butterfly Parnassius clodiusECOLOGICAL ENTOMOLOGY, Issue 2 2004Julia N. Auckland Abstract., 1. A mark,recapture study was conducted on the American Apollo butterfly Parnassius clodius Menetries during three field seasons (1998,2000) to examine its movement patterns over the course of a season within a sagebrush meadow in Grand Teton National Park, Wyoming, U.S.A. The study examined how resources affected butterfly distribution patterns and used mark,recapture data to gain insight into movement differences between sexes and over time. 2. The average straight-line movement of P. clodius was 202 m day,1, adjusted for sampling effort at different distances. Movement estimates in all 3 years were highly correlated with the average distance between plots sampled. 3. Butterfly abundance was correlated positively with per cent cover of its host plant Dicentra uniflora, but this relationship decreased in importance during the peak of the flight period when individuals may be more interested in finding mates. There was a weak, positive correlation between butterfly abundance and the abundance of its primary nectar source, Eriogonum umbellatum in 1999, but no relationship in 2000. 4. Survival, recapture, and transition probabilities were estimated using open population, capture,recapture models. Survival and recapture probability decreased over the course of each season, while the probability of moving between plots increased. Recapture probability was significantly lower for females than for males among all 3 years, but there was no difference between the sexes in survival rate. [source] Fluctuations of Vanessa cardui butterfly abundance with El Niño and Pacific Decadal Oscillation climatic variablesGLOBAL CHANGE BIOLOGY, Issue 5 2003ROBERT VANDENBOSCH Abstract Annual 4th of July Butterfly Count data spanning more than 20 years are examined to explore Vanessa cardui (Painted Lady) population fluctuations with ENSO (El Niño) and Pacific Decadal Oscillation (PDO) indices. California, Colorado and Nebraska censuses exhibit a strong positive correlation with the strong El Niño events of 1982,1983 and 1997,1998 and the weaker event of 1991,1992. Regression analysis shows the population fluctuations are strongly coupled to climate variations on both short (El Niño) and longer (Pacific Decadal Oscillation) time scales. Recognizing the sensitivity to these time scales is important for predicting longer-term global climate change effects. [source] The diversity and abundance of North American butterflies vary with habitat disturbance and geographyJOURNAL OF BIOGEOGRAPHY, Issue 4 2000Scott D. Kocher Abstract Aim We used data from the annual Fourth of July Butterfly Count for the years 1989,97 to examine patterns of species richness and total butterfly abundance across North America and within topographically diverse and disturbed landscapes. Location We analysed counts from 514 different locations in North America. The counts represent all areas of the USA and southern Canada, with a few Mexican sites as well, although most counts were in the eastern USA. Methods First, we standardized published count data according to the effort expended per count (total party-hours). Using regression analysis and analysis of variance, we then examined the impact of latitude, longitude, topographical relief, habitat disturbance and different climatic measures on the species richness and total abundance of butterflies per count. We also examined the abundance of exotic species in disturbed landscapes. Results Our analyses suggest that: (1) species richness is highest at low latitudes and near Rocky Mountain longitudes; (2) the total abundance of individuals is highest in northern US latitudes and Great Plains longitudes; (3) species richness but not total abundance increases with greater topographical relief; (4) species richness and diversity indices are lower in more disturbed habitats; and (5) the abundance of the introduced Pieris rapae (L.) is greater in more disturbed habitats. Main conclusions Different factors control the abundance and species richness of North American butterflies. Along with geographical location, habitat disturbance and topographical variability affect species richness. Our analysis also shows the value of broad-based monitoring regimes, such as the North American Fourth of July Butterfly Count. [source] Effects of plant structure on butterfly diversity in Mt. Marsabit Forest , northern KenyaAFRICAN JOURNAL OF ECOLOGY, Issue 2 2010Nyamweya N. Humpden Abstract Butterflies, like most forest dependent animals are good ecological indicators of the health of the forests they dwell. For example, butterfly species richness decreases after a forest disturbance and fragmentation but a few species may subsequently invade the forest fragment and boost the species richness. Studies were conducted to determine the effects of human activity and seasonal changes on butterfly species in the affected new habitats. Results showed that both seasonal and habitat changes significantly affect the butterfly abundance (P = 0.0001). Similarly, there was significant correlation between plant diversity and butterfly diversity in wet season (r = 0.854) and dry season (r = 0.855). The significance of these studies as a useful tool for sustainable forest use and conservation is discussed. Résumé Les papillons, comme la plupart des animaux dépendant de la forêt, sont de bons indicateurs écologiques de la santé des forêts qu'ils occupent. Par exemple, la richesse d'une forêt en espèces de papillons diminue suite à sa perturbation et à sa fragmentation, mais quelques espèces peuvent par la suite envahir la forêt et booster la richesse en espèces. On a réalisé des études pour déterminer les effets des activités humaines et des changements saisonniers sur les espèces de papillons dans des habitats récemment touchés. Les résultats ont montré que tant les changements saisonniers que les changements de l'habitat affectent significativement l'abondance des papillons (P = 0.0001). De même, il y avait une corrélation significative entre la diversité des plantes et celle des papillons en saison des pluies (r = 0.854) et en saison sèche (r = 0.855). L'on discute de l'importance de ces études comme outil utile à l'utilisation et à la conservation de la forêt. [source] | ||||||||||