Background Estimating the abundance of organisms. Ecology is often referred to as the "study of distribution and abundance". This being true, we would often like to know how many of a certain organism are in a certain place, or at a certain time. Information on the abundance of an organism, or group of organisms is fundamental to most questions in ecology. However, we can rarely do a complete c...

To investigate the uniformity of copper particles in formulation design of copper-coated graphite, a quadrat-based method was presented with the image processing. Firstly, the particles were located by the foreground and background clustering algorithm. Then, an improved uniformity quantification model was established using the size and position of the particles. The findings based on the exper...

A technique for inferring long term time trends in vegetation from permanent quadrat data using the different patterns in the scattergram of the mean and rates of change of attributes, e.g., cover, from individual quadrats over short periods is described. The technique is illustrated using point intercept cover data for Hieracium species from permanent transects in the Waimakariri measured at i...

Synthetic seed banks are a useful tool for tracking how weed populations change over time. By sowing a known number of seeds of a given species within a quadrat with defined boundaries, an investigator can measure the number remaining and thereby calculate demographic rates (e.g., mortality). The alternative is to use in situ seeds and estimate their initial population density via sampling. To ...

We studied vegetation change on 142 permanently marked transects spread throughout tussock grasslands of Otago and Canterbury, in areas subject to both pastoral and conservation management. The transects were established between 1982 and 1986 and re-measured between 1993 and 1999, providing a record of vegetation change at each site over an interval varying from 10 to 15 years. Each transect co...

1. It is of interest to field ecologists to estimate the abundance of a given species in a commonwealth of plants. The method usually employed for this purpose is that of sampling by quadrat. A square lattice-the quadrat-is dropped at random points in the commonwealth, and the number of plants of the given species found in the quadrat is counted. It is thus possible, with repeated sampling, to~...

The influence potential on a quadrat (IPQ) is an index for measuring the ecological effect that trees have on understory vegetation observed in a quadrat of a plot. IPQ is defined as the sum of the effect of every trees in the plot, where the effect depends on the size of the tree and the distance between the tree and the quadrat. Since only the trees in the plot have been observed and not the ...