A novel approach to understanding bird communities using informed diversity estimates at local and regional scales in northern California and southern Oregon.

Jared D Wolfe,Jaime L Stephens,John D Alexander,C John Ralph

doi:10.1002/ece3.5008

Abstract

Assessment and preservation of biodiversity has been a central theme of conservation biology since the discipline's inception. However, when diversity estimates are based purely on measures of presence–absence, or even abundance, they do not directly assess in what way focal habitats support the life history needs of individual species making up biological communities. Here, we move beyond naïve measures of occurrence and introduce the concept of “informed diversity” indices which scale estimates of avian species richness and community assemblage by two critical phases of their life cycle: breeding and molt. We tested the validity of the “informed diversity” concept using bird capture data from multiple locations in northern California and southern Oregon to examine patterns of species richness among breeding, molting, and naïve (based solely on occurrence) bird communities at the landscape and local scales using linear regression, community similarity indices, and a Detrended Correspondence Analysis (DCA). At the landscape scale, we found a striking pattern of increased species richness for breeding, molting, and naïve bird communities further inland and at higher elevations throughout the study area. At the local scale, we found that some sites with species‐rich naïve communities were in fact species‐poor when informed by breeding status, indicating that naïve richness may mask more biologically meaningful patterns of diversity. We suggest that land managers use informed diversity estimates instead of naïve measures of diversity to identify ecologically valuable wildlife habitat.

Highlights

Identification of ecologically valuable habitats for birds is often based on measures of species richness and evenness whereby areas with more biologically meaningful resources are assumed to host heightened levels of diversity
We found a striking pattern of increased species richness for breeding, molting, and naïve bird communities fur‐ ther inland and at higher elevations throughout the study area
Our study provided four important findings: (a) patterns of species richness among breeding, molting, and naïve bird communities varied predictably across the landscape with more species occurring inland rather than nearer the coastline. (b) Irrespective of some stations being nearer to each other, local conditions often resulted in starkly different estimates of species richness. (c) The relative number of species often dif‐ fered between stations when considering breeding, molting, and naïve bird communities, suggesting that habitat value changes with respect to avian life cycle phenology. (d) Informed estimates of spe‐ cies richness provide a more holistic framework to assess the habitat value for birds across their entire life cycle

Summary

John Ralph Klamath Bird Observatory

Follow this and additional works at: https://digitalcommons.mtu.edu/forestry-fp Part of the Forest Sciences Commons. A novel approach to understanding bird communities using informed diversity estimates at local and regional scales in northern California and southern Oregon.

| INTRODUCTION

| MATERIALS AND METHODS

Findings

| DISCUSSION