summarizeTrend: summarizeTrend

In NCRN/NCRNbirds: Data analysis and visualization for NPS I&M bird monitoring.

summarizeTrend

Description

Summarizes trends for an unmarkedFit object using methods from the unmarked package.

Usage

summarizeTrend(object, ...)

Arguments

object

An unmarked fit object such as those created by unmarkedBirds or a list of such fits.

Details

This function simplifies the process of extracting trends from unmarked models (Royal 2004, Kery et al. 2005) generated by the unmarkedBirds function.

The function will return a table, where each row is a different year. Columns include the year, the number of points visited., naive occupancy or abundance for each year, the model coefficient and standard error. The function also returns two sets of estimates of the true occupancy or abundance, by each year. The first, psi, is the inverse model coefficient back transformed to occupancy / abundance and represents the estimated value for a site given its site and visit covariates. The second estimate, z, takes into account not only covariates but also the actual detection history for each site. Each estimate comes with its own upper and lower limits for a 95% CI. Note that as z takes into account the actual detection history, its lower occupancy limit is always at least the naive occupancy, whereas psi has no such lower boundary.

Value

A table which summarizes the trend analysis results. Currently fits occupancy models with only year (factor or numeric) as a site covariate. If the input is a list of unmarked fits, then the function will return a list of table.s

NCRN/NCRNbirds documentation built on Aug. 28, 2023, 12:12 p.m.