11.3.1 Bird Feeding Guild Abundance, Species Richness, and Diversity in Forest Classes
A total of 13,721 individuals of 128 species were included in the analysis; 11 species were excluded because they were raptors and fully aerials, or omnivores. For all feeding guilds, the observed, rarefied, and estimated species richness did not differ significantly among forest classes (Table 11.2). For bark insectivores (BI), observed species richness was significantly higher in > 15-year-old forests on flat areas than in >15-year-old forests on hills; estimated species richness was higher in >15-year – old forests on flat areas compared to 3- to 8-year-old forests (Table 11.2).
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Table 11.1 Description of biophysical variables grouped into three sets of variables: vegetation structure, landscape structure, and spatial structure of sampling sites
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Set of variables
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Description
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Code
|
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Vegetation set
|
|
|
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Stand age
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Age after abandonment following slash-and-burn shifting cultivation
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AGE
|
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Total species richness
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Total number of woody plant species per plot, including adults and saplings
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SPPT
|
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Species richness for adults
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Number of woody plant species >5 cm dbh [diameter at breast (1.3 m) height] per plot
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SPPa
|
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Species richness for saplings
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Number of woody plant species 1-5 cm dbh [diameter at breast (1.3 m) height] per plot
|
SPPs
|
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Abundance of adult individuals
|
Number of individuals of adults per plot
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ABUNa
|
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Abundance of sapling individuals
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Number of individuals of saplings per plot
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ABUNs
|
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Total basal area
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Basal area (m2/ha) of all woody plants per plot, including adults and saplings
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ABT
|
|
Total basal area for adults
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Basal area(m2/ha) of all woody plants for adults per plot
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ABa
|
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Total basal area for saplings
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Basal area (m2/ha) of all woody plants for saplings per plot
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ABs
|
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Mean height of adults
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Mean canopy height (m) for adults per plot
|
Ha
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Mean height of saplings
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Mean canopy height (m) for saplings per plot
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Hs
|
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Total density
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Total number of individuals per hectare
|
TD
|
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Density for adults
|
Number of adults per hectare
|
Da
|
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Density for saplings
|
Number of of saplings per hectare
|
Ds
|
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Simpson diversity index
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Computed for all woody plants, including adults and saplings
|
SIMP
|
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Shannon diversity index Landscape structure set
|
Computed for all woody plants, including adults and saplings
|
SHAN
|
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Proportional abundance of each patch type
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High values indicate dominance of certain successional patch type
|
PLAND
|
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Patch density
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High values indicate higher number of small patches per area unit
|
PD
|
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Edge density at the class level
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High values indicate higher edge density per successional class
|
ED
|
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Overall shape complexity Patch isolation
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High values indicate more irregular patch shape
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SHAPE
ENN
|
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Edge contrast Spatial structure set
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High values indicate higher landscape fragmentation
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TECI
|
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PCNM vectors
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Represents a spectral decomposition of the spatial relationships among the sampling plots and provides a better representation of the spatial structure present in the sampling data than simple geographic coordinates
|
PCNM
|
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Table 11.2 Changes in bird feeding guild species richness (observed and estimated) and diversity for all feeding guilds and for bark insectivores only: rarefaction for all guilds, 1,169 individuals; rarefaction for bark insectivores, 64 individuals. Different letters (a-b) indicate significant differences according to Tukey’s post hoc test (P < 0.05)
Jointly feeding guilds Only bark insectivores
|
Successional
class
|
Total number of samples
|
Total
number
of
individuals
|
Observed number of species
|
95 % Cl (Mao Tau)
|
Number
of
species
(rarefied)
|
95 % СІ
(Мао
Tau)
|
Estimated number of species
|
95 % Cl (Chao 1)
|
Total number of individuals
|
Observed number of species
|
95 % Cl (Mao Tau)
|
Number
of
species
(rarefied)
|
95 %
Cl (Mao Tau)
|
Estimated number of species
|
95 % Cl (Chao 1)
|
|
3-8 year
|
46
|
1,461
|
93a
|
82.96-
103.04
|
95.08a
|
91-97
|
94.23-
|
90.07-
111.02
|
39
|
6“b
|
2.76-9.24
|
7.63a
|
6-8
|
6.38a
|
6.12-9.73
|
|
9-15 year
|
77
|
2,531
|
90“
|
80.36-99.64
|
92.52а
|
88-97
|
99.22-
|
96.11-
113.94
|
84
|
9ab
|
6.26-11.74
|
8.90a
|
7-11
|
9 42“b
|
9.12-12.96
|
|
>15 year on flat
|
87
|
2,934
|
98“
|
89.54-
106.46
|
91.93“
|
86-97
|
99.03-
|
96.84-
111.05
|
162
|
10b
|
8.13-11.87
|
8.73a
|
7-11
|
10.95b
|
10.72-
13.74
|
|
>15 year on hills
|
64
|
2,138
|
91“
|
81.05-
100.95
|
92.93а
|
89-96
|
96.31-
|
93.38-
110.58
|
119
|
T
|
3.87-10.13
|
6.39 a
|
5-8
|
8.45a
|
8.38-9.49
|
|
 |
|
|
|
Conditional
|
|
|
|
|
|
|
|
|
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Fig. 11.2 Amount of variance explained by each set of variables (marginal effect), and the conditional effect explained by all sets of variables for (a) number of individuals and (b) number of species. Unexplained variance is not depicted
