Latest Score:

4/5

in 2019

score trend is down over time
Weight: 15%

The diversity of forest-dwelling birds provides a sense of how well Vermont's forests support bird habitat, food sources, and reproductive success. Further, trees rely on birds for flower pollination, seed dispersal, and pest control1. Examining annual bird counts of forest-dwelling bird species can provide an indication of the quality of the forest habitat in supporting wildlife. Here, forest bird species abundance is assessed using a Living Planet Index (LP1)2. The Living Planet Index gives a sense of how this bird diversity is sustaining over time. A high score means that diversity is high.

1Vermont Center for Ecosystem Studies. 2017. The Status of Vermont Forest Birds: A Quarter Century of Monitoring. Available at: https://ndownloader.figshare.com/files/8175131
2Collen, B., Loh, J., Whitmee, S., McRAE, L, Amin, R. and Baillie, J.E., 2009. Monitoring change in vertebrate abundance: the Living Planet Index. Conservation Biology, 23(2), pp.317-327.

-- Expert interpretation for Forest Bird Diversity is not available--

The score is calculated using a target value and the historical range of the the entire long-term dataset. The higher the score, the closer this year's value is to the target.

Once the score is computed for each year, the trend in scores over time is calculated. If the trend is significantly positive or negative, the long-term trend is marked as increasing or decreasing respectively.

Component Description
Scored as

Distance between maximum and minimum (scaled 1-5)

Target value

Data maximum + 10% of range

Directionality of scores

Higher values in the data are better.

Minimum value used in scoring

Data minimum - 10% of range

Maximum value used in scoring

Data maximum + 10% of range

Data on forest bird counts by species were collected by Vermont Center for Ecostudies1 at forested locations throughout Vermont beginning in 1989, with a more complete survey of the selected sites in 1990. From these data, we computed a Living Planet Index (LPI) 2. We used a beta package for R, rlpi3, to compute the LPI for all bird species. We used equal weighting among species and no sub-groupings. Only those Forest Bird Monitoring sites with a complete record were included: Bear Swamp, Concord Woods, Dorset Bat Cave, Galick Preserve, Maypond, Moosebog, Pease Mountain, Roy Mt WMA, Sandbar WMA, Sugar Hollow, The Cape, and Underhill State Park. Living Planet Index ranges from zero to two. We computed the index and set the target to 1, and the current year is scored as the difference between the target and the current year value, scaled to be between 1 and 5.

1Faccio, S. Vermont Center for Ecostudies. 2019. Forest Bird Monitoring Program. Available at: https://vtecostudies.org/projects/forests/vermont-forest-bird-monitoring-program/
2Collen, B., Loh, J., Whitmee, S., McRAE, L, Amin, R. and Baillie, J.E., 2009. Monitoring change in vertebrate abundance: the Living Planet Index. Conservation Biology, 23(2), pp.317-327.
3Indicators and Assessments Research Unit, Institute of Zoology, Zoological Society of London. Available at: https://github.com/Zoological-Society-of-London/rlpi

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