European Journal of Wildlife Research
Electronic Supplementary Material
Predators and livestock reduce bird nest survival in intensive
Mediterranean farmland
Pedro Beja1, Stefan Schindler1,2, Joana Santana1, Miguel Porto1, Rui Morgado3,4, Francisco
Moreira3, Ricardo Pita5, António Mira5, Luís Reino1
1
EDP Biodiversity Chair, CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos
Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-601 Vairão, Portugal
2
Department of Conservation Biology, Vegetation and Landscape Ecology, University of
Vienna, Rennweg 14, A-1030 Vienna, Austria
3
CEABN/InBio, Centro de Ecologia Aplicada “Professor Baeta Neves”, Universidade Técnica de
Lisboa, Instituto Superior de Agronomia, Tapada da Ajuda, 1349-017 Lisboa, Portugal
4
ERENA – Ordenamento e Gestão de Recursos Naturais SA, Rua Robalo Gouveia, 1-1A, 1900-
392 Lisboa, Portugal
5
CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Pólo de Évora,
Universidade de Évora, Núcleo da Mitra, Apartado 94, 7002-554 Évora, Portugal
1
Table S1. Description and summary statistics of variables related to field characteristics, landscape context and predator abundances used to model nest
failure rates (2002-2003). Summary statistics were computed before the transformation of variables.
Variable (unit)
Description
Transformation Mean ± SD
Range
Field characteristics
Vegetation height (cm)
Mean height of herbaceous vegetation, estimated from 60 evenly spaced
measurements taken along a transect crossing the longest axis of each field.
-
22.1 ± 10.6
5.2 – 55
Bare soil (%)
Proportion of bare soil, estimated from measurements taken at the same 60
evenly spaced points used to estimate vegetation height.
Angular
3.8 ± 7.2
0 – 38
Hedge (%)
Proportion of field perimeter with hedge
Angular
35.3 ± 16.2
13 – 78
Arboreal hedge (%)
Proportion of field perimeter with arboreal hedge
Angular
17.9 ± 13.8
0 – 62
Hedge height (m)
Hedge height
-
10.2 ± 4.3
1.0 – 19.0
Livestock (%)
Proportion of visits (n=4 or 5) to sampling fields with livestock present
Angular
24.3 ± 24.8
0 – 100
Fences (0/1)
Presence of fences at the field edge
-
0.49
0-1
Roads (0/1)
Presence of paved or dirt roads at the field edge
-
0.54
0-1
Irrigation ditches (0/1)
Presence of irrigation ditches at the field edge
-
0.28
0-1
Landscape context (radius 1 km)
Agricultural land (%)
Proportion of arable fields and pastures
Angular
66.2 ± 17.8
31 – 93
Social areas (%)
Proportion of urban areas, isolated farmhouses and infrastructures
Angular
2.0 ± 1.9
0 – 8.9
Forest plantations (%)
Proportion of eucalyptus and pine plantations
Angular
14.8 ± 9.8
0.6 – 42
Semi-natural habitat (%)
Proportion of cork oak woodland, shrubland, marshes and coastal dunes
Angular
15.7 ± 15.3
0.1 – 65
Mean patch size (ha)
Mean size of agricultural patches (MPS)
Logarithmic
56.6 ± 64.3
9.8 – 292
Edge density (km/km2)
Density of edges between agricultural land and other land cover classes
Logarithmic
8.2 ± 2.5
4.2 – 16
Area weighed mean fractal dimension of agricultural patches (AWMFD)
Logarithmic
1.4 ± 0.04
1.3 – 1.4
Density of irrigation channels
Logarithmic
0.6 ± 0.7
0 – 2.6
Shape complexity
2
Irrigation channels (km/km )
2
Variable (unit)
Description
Road network (km/km2)
2
Tree lines (km/km )
2
Shrubby hedges (km/km )
Transformation Mean ± SD
Range
Density of paved and dirt roads
Logarithmic
3.7 ± 1.0
1.4 – 6.4
Density of linear strips with planted trees
Logarithmic
1.2 ± 0.7
0.1 – 2.8
Density of shrubby linear strips
Logarithmic
1.0 ± 0.8
0.1 – 4.5
Predator abundances
Cattle egret (birds/km)
Kilometric index of cattle egret abundance
Logarithmic
45.2 ± 56.1
0 – 321.7
Eurasian jay (birds/km)
Kilometric index of European jay abundance
Logarithmic
2.1 ± 3.1
0 – 12.2
Carrion crow (birds/km)
Kilometric index of carrion crow abundance
Logarithmic
12.7 ± 11.9
0 – 62.6
White stork (birds/km)
Kilometric index of white stork abundance
Logarithmic
9.7 ± 12.2
0 – 62.6
Dog (signs/km)
Kilometric index of feral dog abundance
Logarithmic
2.0 ± 2.0
0 – 11.9
Red fox (signs/km)
Kilometric index of red fox abundance
Logarithmic
2.5 ± 1.9
0 – 8.1
Egyptian mongoose (signs/km)
Kilometric index of Egyptian mongoose abundance
Logarithmic
1.4 ± 1.1
0 – 4.4
European badger (signs/km)
Kilometric index of European badger abundance
Logarithmic
0.3 ± 0.5
0 – 1.9
3
Table S2. Summary statistics of the relative abundances of potential avian nest predators
(birds/km) and mammalian carnivores (signs/km) recorded in spring 2002 and 2003, in
farmland landscapes of southwest Portugal.
Species
MEAN
SD
MAX
% occurrence
(n=57)
Birds
Cattle egret
Bubulcus ibis
45.2 56.1
321.7
89.5
Carrion crow
Corvus corone
12.7 11.9
62.6
86.0
White stork
Ciconia ciconia
9.7 12.2
62.6
80.7
Eurasian jackdaw
Coloeus monedula
9.3 35.3
160.8
10.5
European jay
Garrulus glandarius
2.2
3.1
12.2
45.6
Azure-winged magpie
Cyanopica cyana
0.9
3.7
23.3
8.8
European magpie
Pica pica
0.6
2.0
10.2
10.5
Common raven
Corvus corax
0.5
1.4
7.0
14.0
Red fox
Vulpes vulpes
2.5
1.9
8.1
93.0
Dog
Canis familiaris
2.0
2.0
11.9
47.4
Egyptian mongoose
Herpestes ichneumon
1.4
1.1
4.4
96.5
European badger
Meles meles
0.4
0.5
1.9
38.6
Least weasel
Mustela nivalis
0.07
0.2
0.5
5.3
European genet
Genetta genetta
0.04
0.1
0.6
7.0
Stone marten
Martes foina
0.03
0.1
0.6
14.0
European polecat
Mustela putorius
0.03
0.1
0.5
8.8
Mammals
4
Table S3. Summary of the best AIC models used in variation partitioning, considering
separately the field, landscape and predator sets of variables.
Variables
Predation rate
Trampling rate
Regression coefficients ± SE
Regression coefficients ± SE
Field management
Hedge height
0.11±0.03
Vegetation height
-0.10±0.01
Bare soil
3.96±0.62
-0.04±0.01
Landscape context
Edge density
Semi-natural habitat
-1.09±0.45
Tree lines
Forest plantations
-1.80±0.57
2.64±0.78
-0.53±0.64
-5.05±0.86
White stork
-0.21±0.09
-0.08±0.09
Egyptian mongoose
2.40±0.26
Predator abundances
Dog
0.58±0.20
5
Figure S1. Trend lines derived from multimodel inference (Table 2 in Main Text), describing the
relationships between nest predation rates and variables reflecting field management,
landscape context, and predator abundances. Variable description is given in Table S1 (ESM).
For each explanatory variable, curves were computed from the average model (Table 2 in the
Main Text) by maintaining constant at their average value all other variables.
6
Figure S2. Trend lines derived from multimodel inference (Table 2 in Main Text), describing the
relationships between nest trampling rates and variables reflecting field management,
landscape context, and predator abundances. Variable description is given in Table S1 (ESM).
For each explanatory variable, curves were computed from the average model (Table 2 in the
Main Text) by maintaining constant at their average value all other variables.
7