Sampling of Sparse Species with Probability Proportional to Prediction

Abstract

In this article, a 3P sampling (Probability Proportional to Prediction) approach is presented for surveying sparse species connected to certain types of substrates. The method uses the surveyor's judgement of the probability of finding the species on a substrate as the base for selection of substrates for species inventories. The method is presented together with estimators, variances and variance estimators. The method is first presented for sampling based on all substrates in a study area and then as a subsampling technique in a two-stage design in which plots or strips are selected in a first stage. The presented approach was evaluated as a subsampling technique in a strip survey of calicioid lichen species associated with coarse broadleaf trees. In comparison with a simple random subsampling without replacement, 3P subsampling was in one study area found to be an improvement with 30-55% in terms of standard errors. The improvement was more modest in the other study area, only between 10-16%. The strip survey with 3P subsampling was more cost-efficient than a strip survey without subsampling except in one case. Based on the results in the test, 3P sampling seems to have a potential for sampling sparse species.

Predicting foundation bunchgrass species abundances: model‐assisted decision‐making in protected‐area sagebrush steppe

“…Also, our predicted probability map could be used to target early-detection weed surveillance activities around the perimeters of high priority areas (e.g., areas A and B in Fig. 3), a strategy known as sampling with probability proportional to predictions (Ringvall and Kruys 2005). In the specific setting of sagebrush steppe, both the extent of degradation Wisdom 2009, Davies et al 2011) and the relative paucity of healthy sagebrush steppe in the existing conservation reserve system (Caicco et al 1995, Storms et al 1998) underscores the importance of trying new approaches of prioritization and evidence-based decision-making Wisdom 2009, Chambers et al 2014).…”

Scale dependence of plant species richness in a network of protected areas

“…Probabilistic samplings are less efficient in recording species richness of groups of species characterised by very low detection probabilities (Diekmann et al 2007), as is typical for protected or alien species. Specific sampling strategies are needed to efficiently record the species richness and complementarity of such groups (Newmaster et al 2005;Ringvall and Kruys 2005;Guisan et al 2006;Hedgren and Weslien 2008). The ratio between the rarefaction curves of different groups of species proved to be an interesting tool to understand different features of biological communities, The ''?''…”

Applicability of non-destructive substitutes for leaf area in different stands of Norway spruce (Picea abies L. Karst.) focusing on traditional forest crown measures

“…3P-sampling is a well established and efficient sampling method, resulting in unbiased and thus reliable estimates (e.g., Schreuder et al, 1993). Although mainly used for estimating stand volume by selecting sample trees with a probability proportional to their estimated volume, it has also been used for estimating sparse species (Ringvall and Kruys, 2005) and needle mass (Eckmüllner and Sterba, 2000). Branches with a branch base diameter between 5 and 10 mm were not included in the 3P sample.…”