Table 3 Results of GLMMs of the variation in the acoustic properties of soundscapes.

From: Bird population declines and species turnover are changing the acoustic properties of spring soundscapes

 

Fixed effects

North America

Europe

Estimate (SE)

χ2

DF

p

Estimate (SE)

χ2

DF

p

(a) ADI

Latitude

0.00002 (0.00088)

0.03

1

0.856

−0.0004 (0.0005)

0.78

1

0.376

 

Longitude

0.00002 (0.00035)

0.19

1

0.659

0.0005 (0.0003)

3.57

1

0.059

 

Year

−0.00198 (0.00068)

8.46

1

0.004

−0.0073 (0.0030)

5.98

1

0.014

(b) AEI

Latitude

−0.00001 (0.00009)

0.01

1

0.949

−0.0005 (0.0005)

1.25

1

0.263

 

Longitude

−0.00009 (0.00003)

0.08

1

0.782

−0.0005 (0.0003)

2.84

1

0.092

 

Year

0.00144 (0.00057)

6.47

1

0.011

0.0053 (0.0030)

3.08

1

0.079

(c) BI

Latitude

0.00004 (0.00009)

0.16

1

0.691

−0.0002 (0.0005)

0.25

1

0.621

 

Longitude

0.00002 (0.00003)

0.44

1

0.508

0.0004 (0.0003)

2.26

1

0.132

 

Year

−0.00217 (0.00088)

6.08

1

0.014

−0.0056 (0.0021)

6.91

1

0.009

(d) H

Latitude

0.00010 (0.00009)

1.38

1

0.239

−0.0004 (0.0005)

0.86

1

0.353

 

Longitude

0.00006 (0.00004)

3.19

1

0.074

0.0006 (0.0003)

4.65

1

0.031

 

Year

−0.00625 (0.00175)

12.79

1

<0.001

−0.0095 (0.0030)

10.01

1

0.002

  1. Annual values for each acoustic index were standardised at the site-level prior to analyses.
  2. (a) Acoustic Diversity Index (ADI), (b) Acoustic Evenness Index (AEI), (c) Bioacoustic Index (BI) and (d) Acoustic Entropy (H) in 202737 NA-BBS sites across North America between 1996 and 2017 and in 16524 PECBMS sites across Europe between 1998 and 2018.
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