What sampling method involves collecting organisms within a specific band along an environmental gradient?

The correct choice is the method known as a belt transect, which involves systematically collecting organisms along a specific band or strip that is placed along an environmental gradient. This approach allows researchers to analyze how the distribution and abundance of organisms change in relation to environmental factors, such as changes in vegetation, soil type, or moisture levels. By sampling within this defined area, scientists can obtain a clear picture of how ecological features influence biodiversity.

In contrast, quadrat sampling typically involves marking out a square or rectangular area within which all organisms are counted or measured, without necessarily addressing a gradient. Point sampling involves taking samples from specific, randomly chosen points in an area, which may not provide the same comprehensive view as the belt transect method. Stratified sampling divides the study area into different subgroups or strata and samples each one proportionally, but it does not specifically focus on a continuous band along a gradient like the belt transect does.