What metrics are included?

Overview

AbundanceR generates summary information that describes the bird community and the program calculates estimates of abundance (birds per survey) for up to 3 groups of surveys. Surveys can be grouped by selecting them individually or by selecting a point grouping. A survey is a single visit to a point.

AbundanceR calculates the following metrics:

1) Abundance estimates: detections (raw data) and abundance (birds per survey) by species and group.

    Output fields:

    a) Group

    b) Species

    c) Surveys

    d) Detections per survey

    e) Abundance (birds per survey)

    f) Abundance: Upper and Lower 90% confidence intervals

    g) Abundance: Upper and Lower 95% confidence intervals

    h) Detection probabilities by species and group (Available when saving detailed results in Excel)

The above metrics will provide information about the detection probabilities of different species and the estimated abundance of birds for a group of surveys. The abundance information is useful if you want to compare abundance among up to 3 groups to see if your management actions are supporting the species in the abundances that you expect. If key species have low abundances and/or low detection probabilities, it likely means that you will need larger sample sizes to effectively monitor these species (Dorazio et al. 2006). You may decide to select an alternative target species that is found in higher abundances or has a higher detection probability.

To convert abundance (birds per survey) into birds/area, you need to know the area of the count circle. The Knutson (2008) protocol uses a 100 m radius count circle. This is equivalent to an area of 3.14 ha. To calculate density in birds/ha you divide the birds/survey by 3.14. These calculations can be done after you download the output file.

2) Community summaries based on habitat association

This summary can be used to assess the percentage of all bird abundance made up of early successional, forest edge, forest interior, waterbirds, shorebirds, and seabirds. The program also presents the total number of species detected in each group. For example, if your management actions are designed to benefit early successional species, you might want to compare a group of points over time to see if the percentage composition of early successional species is increasing as expected.

This analysis is also useful if you plan to employ reforestation on a management unit based on a threshold. For example, when the community composition of forest interior birds falls below an established threshold, you will begin reforestation the following season to maintain habitat suitable for forest interior species.
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