نتایج جستجو برای: transect

تعداد نتایج: 3966  

Investigation of the relationship between plant species and environmental factors plays an important role in plant ecology. The present study aimed to develop the best predicting model for distribution of Prangos uloptera DC. using logistic regression (LR) and Maximum Entropy Methods (MaxEnt) in its habitat in the southern rangeland of Ardabil province, Iran. Vegetation data (presence and absen...

2006

As the largest ocean, the Pacific is intricately linked to major changes in the global climate system that took place during the Cenozoic. Throughout the Cenozoic the Pacific plate has had a northward component. Thus, the Pacific is unique, in that the thick sediment bulge of biogenic-rich deposits from the currently narrowly focused zone of equatorial upwelling is slowly moving away from the e...

2005
FRED L. RAMSEY

With data from line transeot surveys, the pattern of distances at which animals are detected provides the information for estimating the area which the observer effectively surveys. This paper suggests a parametric structure for the problem wherein this area is characterized by an effective half-width parameter which appears as a scale parameter in the distributions of detection distances. Seve...

Journal: :Biometrics 2010
T A Marques S T Buckland D L Borchers D Tosh R A McDonald

Distance sampling is a widely used methodology for assessing animal abundance. A key requirement of distance sampling is that samplers (lines or points) are placed according to a randomized design, which ensures that samplers are positioned independently of animals. Often samplers are placed along linear features such as roads, so that bias is expected if animals are not uniformly distributed w...

Journal: :Evolution; international journal of organic evolution 2004
Jay F Storz Jean M Dubach

In populations that are distributed across steep environmental gradients, the potential for local adaptation is largely determined by the spatial scale of fitness variation relative to dispersal distance. Since altitudinal gradients are generally characterized by dramatic ecological transitions over relatively short linear distances, adaptive divergence across such gradients will typically requ...

2005
Marika Tuiwawa

The Monasavu catchment was selected as an additional study site for biodiversity assessment at the top of the PABITRA wet-zone landscape transect on Viti Levu. The site consists of upland rain forest with cloud forest and a freshwater lake. The lake was constructed to supply hydroelectric power. The biota of the area has been little studied, but initial surveys indicate that many endemic specie...

2012
Paul B. Conn Jeffrey L. Laake Devin S. Johnson

Ecologists often use multiple observer transect surveys to census animal populations. In addition to animal counts, these surveys produce sequences of detections and non-detections for each observer. When combined with additional data (i.e. covariates such as distance from the transect line), these sequences provide the additional information to estimate absolute abundance when detectability on...

Journal: :Conservation biology : the journal of the Society for Conservation Biology 2008
Nick M Haddad Brian Hudgens Chris Damiani Kevin Gross Daniel Kuefler Ken Pollock

Determining population viability of rare insects depends on precise, unbiased estimates of population size and other demographic parameters. We used data on the endangered St. Francis' satyr butterfly (Neonympha mitchellii francisci) to evaluate 2 approaches (mark-recapture and transect counts) for population analysis of rare butterflies. Mark-recapture analysis provided by far the greatest amo...

2011
Andreas Lang Matthias Dolek Bernhard Theißen Andreas Zapp

Butterflies and moths (Lepidoptera) have been suggested for the environmental monitoring of genetically modified (GM) crops due to their suitability as ecological indicators, and because of the possible adverse impact of the cultivation of current transgenic crops. The German Association of Engineers (VDI) has developed guidelines for the standardized monitoring of Lepidoptera describing the us...

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