Modified Staff-ball Technique for Densely Vegetated Areas

Abstract

Staff-ball technique is a method used to measure the horizontal cover of vegetation in an area. For the occupancy study of two threatened avian species, a modified version of this method has been developed, employed and standardized in the field, to collect data that has been used as proxy for visibility of these species through the undergrowth in plantations within Western Ghats, India. This modified cost-effective technique is very useful in areas which are highly vegetated with undulating terrain, as opposed to its original use in grasslands. Two staffs and a ball are the main equipment used, wherein a central staff with ball is placed within vegetation and viewed using a peripheral staff at a fixed height from different points in an imaginary circle. A weakness of this technique is the difficulty in alignment with the central staff-ball, which may be rectified by the use of a laser rangefinder.

An investigation into the patterns of occupancy and detection of two endemic montane bird species, in Southern Western Ghats, India

“…Details about the covariates measured/observed can be found in Method S1.2. While other covariate observations were straightforward, a modified staff-ball technique for measurement of horizontal cover/visibility was used during the study (Pop, 2019) .…”

“…Vegetation parameters collected were of three types: understorey height, canopy height and horizontal cover/visibility. The first two were measured by visual estimation whereas horizontal cover was measured using a modified Staff-ball technique (Pop, 2019). Five measurements each of the former two were taken for every hectare, whereas three measurements of horizontal cover were taken per hectare.…”

“…Mock surveys were carried out at several plots near Ooty (Nilgiris district, Tamil Nadu). Employment and standardization of various covariate estimation was done in this location, especially the modified staff-ball technique for horizontal cover estimation (Pop, 2019).…”

“…All birds (besides the focal species) heard or seen within the survey were also noted down and checklists of all surveys were uploaded in eBird platform to aid further (Pop, 2019) .…”