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Wild boar ecology: a review of wild boar ecological and demographic parameters by bioregion all over Europe

Authors:
  • IREC (CSIC-UCLM-JCCM)
  • University of Sassari - Italy
EXTERNAL SCIENTIFIC REPORT
APPROVED: 1 March 2022
doi:10.2903/sp.efsa.2022.EN-7211
www.efsa.europa.eu/publications
1
EFSA Supporting publication 2022:EN-7211
Wild boar ecology: a review of wild boar ecological and
demographic parameters by bioregion all over Europe
ENETWILD-consortium, Pascual-Rico R, Acevedo P, Apollonio M, Blanco-Aguiar JA,
Body G, del Rio L, Ferroglio E, Gomez A, Keuling O, Plis K, Podgórski T, Preite L, Ruiz-
Rodriguez C, Scandura M, Sebastian M, Soriguer R, Smith GC, Vada R, Zanet S, Vicente
J and Carpio A.
Abstract
The definition of the most relevant parameters that describe the wild boar (WB) population
dynamics is essential to guide African swine fever (ASF) control policies. These parameters should
be framed considering different contexts, such as geographic, ecological and management
contexts, and gaps of data useful for the parameter definition should be identified. This
information would allow better harmonized monitoring of WB populations and higher impact of
ASF management actions, as well as better parametrizing population dynamics and
epidemiological models, which is key to develop more efficient cost-benefit strategies. This report
presents a comprehensive compilation and description of parameters of WB population dynamics,
including general drivers, population demography, mortality, reproduction, and spatial behaviour.
Beyond the collection of current available data, we provided an open data model to allow
academics and wildlife professionals to continuously update new and otherwise hardly accessible
data, e.g. those from grey literature which is often not publicly available or only in local languages.
This data model, conceived as an open resource and collaborative approach, will be incorporated
in the European Observatory of Wildlife (EOW) platform, and include all drivers and population
parameters that should be specified in studies on wild boar, and wildlife in general, ecology and
epidemiology at the most suitable spatio-temporal resolution. This harmonized approach should
be extended to other taxa in the future as an essential tool to improve European capacities to
monitor, to produce risk assessment and to manage wildlife under an international perspective.
© European Food Safety Authority, 2022
Key words: Wild boar ecology, population dynamics, bioregion Europe
Question number: EFSA-Q-2022-00047
Correspondence: biohaw@efsa.europa.eu
Wild boar ecology
www.efsa.europa.eu/publications
2
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Disclaimer: The present document has been produced and adopted by the bodies identified
above as authors. This task has been carried out exclusively by the authors in the context of a
contract between the European Food Safety Authority and the authors, awarded following a
tender procedure. The present document is published complying with the transparency principle
to which the Authority is subject. It may not be considered as an output adopted by the Authority.
The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights
of the authors.
Acknowledgements: We acknowledge EFSA ALPHA and DATA units, and ENETWILD partners
and Bernad A., Martínez A. and Tardón A. for reviewing this manuscript. We are grateful to
ENETWILD collaborators (listed on http://www.enetwild.com/collaborators).
Suggested citation: ENETWILD-consortium, Pascual-Rico R, Acevedo P, Apollonio M, Blanco-
Aguiar JA, Body G, del Rio L, Ferroglio E, Gomez A, Keuling O, Plis K, Podgórski T, Preite L, Ruiz-
Rodríguez C, Scandura M, Sebastian M, Soriguer R, Smith GC, Vada R, Zanet S, Vicente J, Carpio
A, 2022. Wild boar ecology: a collection of wild boar ecological and population dynamics
parameters by bioregion all over Europe. 2022:EN-7211. 27 pp. doi:10.2903/sp.efsa.2022.EN-
7211
ISSN: 2397-8325
© European Food Safety Authority, 2021
Wild boar ecology
www.efsa.europa.eu/publications
3
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Summary
Background and objectives: Wild boar (WB) is an ecologically very plastic species, with
potentially rapid population growth rates. Overall, WB populations are still growing and expanding
despite high mortality rates. This ability to adapt to a wide array of environmental and climatic
conditions makes WB population dynamics highly variable across the European continent,
requiring a deeper understanding of local and regional variations over its distribution range. In
order to guide African swine fever (ASF) control policies, it is essential: (i) to define which basic
parameters of WB population dynamics are most relevant, (ii) to understand them in a context-
dependent manner, based on their variation in given geographical, ecological and management
contexts (hereafter called WB population bioregions”
1
) and conditioned by drivers, and finally
(iii) quantifying their values and range, identifying gap areas or contexts, both management and
epidemiological. The potential impact of the results obtained by this review on WB ecological and
population dynamics parameters for ASF management in the EU are:
Planning integrated and harmonized (comparable) monitoring of WB population dynamics
trends and impacts over space and time under different scenarios.
Monitoring the effects of ASF management actions under an adaptive approach, to inform
future decision-making.
Parametrizing population dynamics and epidemiological models to develop most efficient
cost-benefit strategies.
The aim of the present report is to produce a comprehensive compilation and description of
parameters on WB population dynamics throughout Europe.
Methodology: We compiled WB demographic parameters using a literature review on WB
population dynamics and drivers throughout Europe. From each publication we extracted
available data on parameters describing the basic aspects of wild boar population dynamics
relevant to understand disease dynamics and improve science-based ASF management, i.e.: (1)
description of publication (year of publication, journal, country); (2) general ecological factors or
drivers (bioregion, predator presence, hunting pressure, supplementary feeding and ASF
presence); (3) population characteristics (e.g. density, sex ratio, body size, group size, age
structure by age…); (4) mortality (due to predation, diseases, hunting harvest, and others such
as road kills); (5) reproduction parameters (e.g. litter size, proportion of pregnant females); and
(6) spatial behaviour (e.g. proportion of dispersants, dispersal period, distance travelled, home
ranges).
Results: One of the main difficulties to produce such a harmonized database was the wide
diversity of parameters describing WB population dynamics and different methods applied (e.g.,
for relative abundance). Also, even for peer reviewed sources, there is lack of descriptive
information or this is not sufficiently detailed and/or standardized about the specific context and
main drivers determining population dynamics: spatio-temporal, management (e.g., population
control, hunting), ecological and environment scenarios. All this may impede further use of data
as they are not always comparable. A case example to illustrate the usefulness of such data
collection is presented, analysing the relationship between WB population decrease (%, based
on known densities) and pre-ASF density, considering only the countries where ASF is widespread
and information available. This simple example provided insights into the possible impact of ASF
1
Areas of Europe that result from reducing the dimensionality of the environmental variables into a set
of linearly uncorrelated and independent components (ENETWILD consortium et al. 2021).
Wild boar ecology
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4
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
and culling policies on WB populations, and what the scenario could be if ASF would spread all
over Europe.
Conclusions:
Beyond the collection of current available data, we provided an open data model to allow
academics and wildlife professionals to continuously update population parameters with
new and/or low accessible data (i.e., grey literature which is not public or only available
in local languages). This data model, to be conceived as an open resource and
collaborative approach, has been incorporated into the European Observatory of Wildlife
2
(EOW) platform.
To overcome the lack, or when available, unharmonized information, our data model
includes the main potential drivers and population parameters that should be specified in
every study on wild boar (wildlife in general) ecology and epidemiology at the proper
spatio-temporal resolution.
Even when we mostly focused on recent data (mainly from 2010 onwards), the temporal
frame of available data does not always represent the current situation. WB populations
have been increasing during the last decade in the absence of ASF, and in certain regions
the direct impact of ASF and/or reactive and proactive policies have led to very different
scenarios. Therefore, recent data is needed.
The immediate potential impact of making available the information we reviewed here
on WB ecological and population dynamics parameters are (i) better understanding the
impact of ASF and ASF-management on wild boar populations and (ii) to identify gaps in
data, areas or management contexts to plan integrated and harmonized monitoring of
WB population dynamics trends (e.g. EOW). In addition, (iii) reliable parameters are now
available to feed population dynamics and epidemiological models.
Next steps that have been identified are:
o This harmonized approach should be extended to other taxa as an essential tool
to improve European capacities to monitor, to produce risk assessment and to
manage wildlife under an international perspective. The EOW aims hosting a
virtual space in the web and promote this activity among wildlife professionals
and academics.
o To promote the use of common standards to record and publish ecological and
population dynamics parameters.
o To continue data collection in the case of WB, including those from grey
literature.
2
A network of “observation points” funded by EFSA which is provided by collaborators from all European
countries capable to monitor wildlife population at European level in the long term
(https://wildlifeobservatory.org/).
Wild boar ecology
www.efsa.europa.eu/publications
5
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Table of contents
Abstract ............................................................................................................................... 1
Summary ............................................................................................................................. 3
1. Introduction .............................................................................................................. 6
1.1. Background and Terms of Reference as provided by the requestor ............................... 6
1.2. Scope of the report ................................................................................................... 6
2. Methodology ............................................................................................................. 8
2.1. Bioregions ................................................................................................................. 8
2.2. Comprehensive compilation and description of data on WB population dynamics
throughout Europe following a standardised data model .............................................. 9
3. Results and discussion ............................................................................................. 14
3.1. General characteristics of articles and drivers identified ............................................. 14
3.2. Density, population structure and aggregation parameters ......................................... 14
3.3. Average body weight by sex an age group ................................................................ 16
3.4. Mortality (survival) by sex and age group ................................................................. 16
3.5. Reproduction .......................................................................................................... 18
3.6. Spatial dispersal parameters .................................................................................... 18
4. Conclusions and further steps .................................................................................. 20
References ......................................................................................................................... 21
Annex A Studies on basic aspects of wild boar population dynamics all over Europe ........ 23
Wild boar ecology
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6
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
1. Introduction
1.1. Background and Terms of Reference as provided by the
requestor
This contract was awarded by EFSA to Universidad de Castilla-La Mancha, contract title: Wildlife:
collecting and sharing data on wildlife populations, transmitting animal disease agents, contract
number: OC/EFSA/ALPHA/2016/01 01.
The terms of reference for the present report (specific contract 9) were (deliverable D5.1): Wild
boar ecology: to develop studies on basic aspects of WB population dynamics all over Europe
(particularly the collection of ecological parameters by bioregion). This deliverable is due by
November 2021.
1.2. Scope of the report
The ENETWILD consortium (www.enetwild.com) implemented an EFSA funded project whose
main objective has been the collection of information regarding the geographical distribution and
abundance of WB and other ungulates throughout Europe to subsequently create geospatial tools
to be used in further risk assessment of diseases, such as African swine fever (ASF) in the case
of wild boar (WB).
Currently, the lack of standardized information WB population dynamics covering the necessary
range of biogeographical, management, socio-economic and cultural factors is impeding the use
of such data at the European level, hampering risk assessments (ENETWILD et al. 2018a, b;
2019b, 2020). Biased, incomplete, or simulated parameters are normally used for these purposes,
and their regional variation is not considered. The situation is further complicated by two factors:
o There exists a wide diversity of parameters to describe WB population dynamics and dif-
ferent methods are applied, which are not always appropriate and/or comparable
(ENETWILD consortium et al. 2018a, 2019b, 2020).
o The temporal frame of available data does not always represent the current situation. WB
populations have been increasing over during the last decade in the absence of ASF, and
in certain regions the direct impact of ASF and/or reactive and proactive policies have led
to very different scenarios (EFSA et al. 2020).
Compiling and generating valid up-to-date information on WB population dynamics is needed,
following harmonised methods and filtering by standards of quality. Recent activity has been
restricted to density and distribution data but not to population dynamics (ENETWILD consortium
et al. 2019a, 2019b, 2020). There is a large body of literature describing basic aspects of WB
population dynamics. However, this literature is extremely biased towards certain regions of its
native range (Central Europe) and certain parameters (reproduction and spatial ecology). WB
population parameters are largely determined by different drivers including natural and human-
related extrinsic factors influencing ecological processes and population dynamics. Population
models addressing the drivers that may affect WB populations depend on the local and regional
variation, and the scarce literature mainly refers to Central European WB populations (e.g., Bieber
and Ruf 2005, Vetter et al. 2020).
WB is ecologically very plastic, with potentially rapid population growth rates. WB populations still
growing and expanding despite high mortality rates. They are also able to adapt to a wide array
of climatic conditions (ENETWILD consortium et al. 2019b). All of this makes WB population
dynamics highly variable across the continent, requiring a deeper understanding of local and
Wild boar ecology
www.efsa.europa.eu/publications
7
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
regional variations over its distribution range. The essential steps to guide ASF control policies
are: (i) defining which basic parameters of WB population dynamics are most relevant, (ii)
understanding them in a context-dependent manner, based on their variation in given
geographical, ecological and management contexts (hereafter called “WB population bioregions”)
and conditioned by drivers, and finally (iii) quantifying these parameters (once data gaps are
identified). The potential impact of the results obtained by this review on WB ecological and
population dynamics parameters for ASF management in the EU are:
o Better planning integrated and harmonized (comparable) monitoring of WB population dy-
namics trends and impacts over space and time under different scenarios and drivers oc-
curring in Europe (e.g., protected areas, agricultural land, hunting grounds; management
schemes such as artificial feeding or not), and epidemiological situations (pre-ASF, during
or post-ASF; at a local outbreaks scale and over large frontlines and regions affected by
ASF).
o Monitoring the effects of ASF management actions under an adaptive approach, that is,
information is collected continuously, and this is used to improve biological (including the
human dimension) understanding and to inform future decision-making. For example,
changing hunting strategies to achieve the most effective method WB population reduction
(Massei et al. 2011).
o Parametrizing population dynamics models (disentangling factors regulating population dy-
namics such as compensatory growth, density dependence, top-down control by predators,
stochasticity) and epidemiological models (e.g., risk analysis, control options). Only sci-
ence-based modelling should be accepted to guide policy, for instance, to develop most
efficient cost-benefit strategies: control and eradication of ASF in different scenarios (ASF
affecting large areas, local outbreaks, ASF-free zones) and epidemiological stages of ASF
(epidemic, endemic).
In April 2021, the ENETWILD consortium proposed a number of research protocols for designing
studies/pilot trials to evaluate and to improve effectiveness of WB management in relation to
African swine fever virus (https://enetwild.com/wp-
content/uploads/2021/06/ENETWILD_report_D3.1_SC8_approved_EFSA_for_publication_websit
e-2-2.pdf). This previous report presented twelve research objectives (ROs) grouped into six
categories, the first of which addressed aspects of WB ecology, i.e., studies on basic aspects of
WB population dynamics and assessment of the factors that determine the presence of WB near
outdoor pig farms. Following recommendations by RO1 (Studies on basic aspects of WB
population dynamics all over Europe the aim of the present report is to produce a comprehensive
compilation and description of data on WB population dynamics throughout Europe. This will
facilitate further understanding of disease dynamics, improve science based ASF management,
and will help to identify and prioritize data gaps over the (bio)regions and contexts of Europe.
This will also be useful to determine the main drivers of WB population dynamics and to propose
the approach and design of short-term field research to address these gaps.
Wild boar ecology
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8
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
2. Methodology
2.1. Bioregions
For summarizing and grouping population and ecological parameters of WB, we considered the
European bioregions determined by ENETWILD consortium et al. (2021) (see Figure 1).
Bioregions are areas of Europe that result from reducing the dimensionality of the environmental
variables into a set of linearly uncorrelated and independent components (see Pittiglio et al 2018).
Bioregion has been included as predictor factor in previous ENETWILD wild boar abundance
models, allowing the inclusion of new predictors which help to solve regional or local misleading
predictions.
Figure 1: Map showing the bioregion classification used to subgroup the data for modelling
purposes (ENETWILD consortium et al. 2021).
Wild boar ecology
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9
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
2.2. Comprehensive compilation and description of data on WB
population dynamics throughout Europe following a
standardised data model
We compiled and described data on WB population dynamics and drivers (e.g., management
strategies) following the standardized data model (proposed by ENETWILD,
https://enetwild.com/wp-
content/uploads/2021/06/ENETWILD_report_D3.1_SC8_approved_EFSA_for_publication_websit
e-2-2.pdf). Data collection following these standards guarantees that sufficient information (e.g.,
on methods) was collected to validate data (e.g., density values).
For this purpose, we compiled population dynamics and ecological data using a narrative literature
review. We followed the guidelines of systematic reviews (e.g., Pullin and Knight 2009). The
protocol followed a strict method to guarantee transparency and to minimise sources of bias. We
searched the Scopus and WOS databases by using a search string that combined different terms
related to the WB population and ecological parameters of interests. The search was made in
titles, abstracts and keywords in English-written articles published until June 2021 in the Scopus
and WOS databases (see Table 1 for the full search string).
There may be a large amount of reviewable literature (including grey literature), as WB
populations have grown markedly in recent years, and methods (e.g., telemetry) have greatly
developed. Unpublished and grey literature was researched from other sources of internet (e.g.,
Google scholar) and through contact with researchers, administrations and wildlife managers
collaborating with ENETWILD.
Table 1. List of keywords used in the systematic review.
Scopus + WOS
( TITLE-ABS-KEY ( "wild boar" ) AND ( TITLE-ABS-KEY ( population ) OR
TITLE-ABS-KEY ( dynamic ) ) OR ( TITLE-ABS-KEY ( movement ) OR TITLE-
ABS-KEY ( gps ) OR TITLE-ABS-KEY ( telemetry ) ) ) AND ( LIMIT-TO (
DOCTYPE , "ar" ) ) AND ( EXCLUDE ( SUBJAREA , "IMMU" ) OR EXCLUDE
( SUBJAREA , "BIOC" ) OR EXCLUDE ( SUBJAREA , "MEDI" ) OR EXCLUDE
( SUBJAREA , "ARTS" ) ) AND ( LIMIT-TO ( AFFILCOUNTRY , "Italy" ) OR
LIMIT-TO ( AFFILCOUNTRY , "Spain" ) OR LIMIT-TO ( AFFILCOUNTRY ,
"Germany" ) OR LIMIT-TO ( AFFILCOUNTRY , "France" ) OR LIMIT-TO (
AFFILCOUNTRY , "Poland" ) OR LIMIT-TO ( AFFILCOUNTRY , "United
Kingdom" ) OR LIMIT-TO ( AFFILCOUNTRY , "Portugal" ) OR LIMIT-TO (
AFFILCOUNTRY , "Sweden" ) OR LIMIT-TO ( AFFILCOUNTRY , "Russian
Federation" ) OR LIMIT-TO ( AFFILCOUNTRY , "Croatia" ) OR LIMIT-TO
( AFFILCOUNTRY , "Czech Republic" ) OR LIMIT-TO ( AFFILCOUNTRY ,
"Hungary" ) OR LIMIT-TO ( AFFILCOUNTRY , "Switzerland" ) OR LIMIT-
TO ( AFFILCOUNTRY , "Austria" ) OR LIMIT-TO ( AFFILCOUNTRY ,
"Netherlands" ) OR LIMIT-TO ( AFFILCOUNTRY , "Belgium" ) OR LIMIT-
TO ( AFFILCOUNTRY , "Denmark" ) OR LIMIT-TO ( AFFILCOUNTRY ,
"Slovenia" ) OR LIMIT-TO ( AFFILCOUNTRY , "Lithuania" ) OR LIMIT-TO
( AFFILCOUNTRY , "Norway" ) OR LIMIT-TO ( AFFILCOUNTRY , "Greece"
) OR LIMIT-TO ( AFFILCOUNTRY , "Bulgaria" ) OR LIMIT-TO (
AFFILCOUNTRY , "Romania" ) OR LIMIT-TO ( AFFILCOUNTRY , "Serbia"
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
) OR LIMIT-TO ( AFFILCOUNTRY , "Slovakia" ) OR LIMIT-TO (
AFFILCOUNTRY , "Estonia" ) OR LIMIT-TO ( AFFILCOUNTRY , "Turkey" )
OR LIMIT-TO ( AFFILCOUNTRY , "Finland" ) OR LIMIT-TO (
AFFILCOUNTRY , "Latvia" ) OR LIMIT-TO ( AFFILCOUNTRY , "Belarus" )
OR LIMIT-TO ( AFFILCOUNTRY , "Ukraine" ) OR LIMIT-TO (
AFFILCOUNTRY , "Ireland" ) OR LIMIT-TO ( AFFILCOUNTRY , "Iceland" )
OR LIMIT-TO ( AFFILCOUNTRY , "Armenia" ) OR LIMIT-TO (
AFFILCOUNTRY , "Georgia" ) OR LIMIT-TO ( AFFILCOUNTRY , "North
Macedonia" ) )
From each publication we extracted available data on parameters describing the basic aspects of
WB population dynamics relevant to understanding disease dynamics and improve science-based
ASF management: (1) its general description (year of publication, journal, country); (2) general
ecological factors (bioregion, predator presence, hunting pressure, supplementary feeding and
ASF presence); (3) population characteristics (e.g. density, sex ratio, body size, group size, age
structure by age…); (4) mortality (due to predation, diseases, by harvest, and others as road
kills); (5) reproduction parameters (e.g. litter size, proportion of pregnant females); and (6)
spatial behaviour (e.g. proportion of dispersants, dispersal period, distance travelled, home
ranges) (see Tables 2 to 7, indicating response categories and units).
Wild boar ecology
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11
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Table 2. General characteristics of articles and drivers identified.
Location and period
Country
Region
Location
Sampling year
Management, popula-
tion, and environmen-
tal drivers
Bioregion
Supplementary feeding (Y/N)
Predator presence (Y/N)
Predator spp
ASF presence (Y/N)
Epidemic/endemic (Y/N)
Land use
Main biome
Climate
Precipitation
Population control (incl. hunting) Y/N?
Population control method
Table 3. Density, population structure and aggregation data searched in articles.
Density, population
structure and aggre-
gation
Winter local density (ind/km2)
Spring local density (ind/km2)
Summer local density (ind/km2)
Autumn local density (ind/km2)
Local density (ind/km2)
Abundance
Abundance method (Measure units)
Absolute abundance (individuals)
Carrying capacity (K, ind/km2)
Sex ratio (males:females)
Foetus
Juvenile
Yearling
Adult
Population (Age not specified)
Group size (number of individuals)
Male
Female (maternal groups)
Population (Spring)
Population (Summer)
Population (Autumn)
Population (Winter)
Population (year)
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Age structure (% of classes)
Juvenile male
Yearling male
Adult male
Male (age not specified)
Juvenile Female
Yearling Female
Adult Female
Female (age not specified)
Juvenile (sex not specified)
Yearling (sex not specified)
Adults
Population growth rate (r)
Recruitment rate (young:adults)
Table 4. Average body size was reported in this review when it was described in articles, by sex
an age group.
Body size
Juvenile male
Yearling male
Adult male
Male (age not specified)
Juvenile female
Yearling female
Adult female
Female (age not specified)
Juvenile (sex not specified)
Yearling (sex not specified)
Adults (sex not specified)
Population
Table 5. Mortality (survival) data was searched in articles by sex and age group.
Mortality (survival)
Natural: by predator
Juvenile male
Yearling male
Adult male
Male (age not specified)
Juvenile female
Yearling female
Adult female
Female (age not specified)
Juvenile (age not specified)
Population (age and sex not specified)
Natural: by disease
Other: road kills
Natural mortality
By harvest
Mortality (natural + harvest)
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Table 6. Reproduction data searched in articles.
Reproduction y
Litter size
Juvenile
Yearling
Adult
Female (age not
specified)
Foetus/female
Pregnant female (proportion, %)
Juvenile
Yearling
Adult
Female (age not
specified)
Seasonality of reproduction (% of pregnant females)
1 to 12
Table 7. Movement parameters searched in articles.
Movement
Juvenile dispersion: period
(month/season)
Juvenile Male
Yearling Male
Juvenile Female
Yearling Female
Juvenile
Yearling
Dispersion: maximum distance (km)
Juvenile Male
Yearling Male
Adult Male
Male (age not specified)
Juvenile Female
Yearling Female
Adult Female
Female (age not specified)
Juvenile (sex not specified)
Yearling (sex not specified)
Adult (sex not specified)
Family group
Period
Population
Proportion of dispersants (%)
Male
Female
Population (sex not specified)
Annual home range (50 & 95% K)
based on X months
(km2)
Male (50%)
Male (95%)
Maternal group (50%)
Maternal group (95%)
Female (95%)
Population (95%)
Population (50%)
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Annual home range (Convex polygon),
MPC based on X months
(km2)
Juvenile male
Yearling male
Adult male
Male (age not specified)
Juvenile female
Yearling female
Adult female
Female (age not specified)
Juvenile (sex not specified)
Population
Family group
Yearling
3. Results and discussion
We initially identified found 2391 articles of potential relevance, once duplicates were eliminated.
We screened the articles to identify ecological and population dynamics parameters. After that,
we removed those articles that did not present such parameters. The complete list of selected
articles (n=424) is presented as an electronic appendix
(https://doi.org/10.5281/zenodo.6327062).
3.1. General characteristics of articles and drivers identified
As for the general characteristics of articles and main drivers identified, reviewed articles
established their study areas over 32 countries of the continental Europe, comprising published
studies from 1977 until 2021 (June). Most data came from 1-year or less duration studies (69.8%
of extracted parameters), but others (30.2%) were estimated for longer periods, which ranged
up to fifty years.
According to European bioregions, East (27.7%), South (35.9%) and West (33.2%) collected
most of the available WB population dynamic parameters, whereas the North bioregion showed
lower data availability (3.2%).
In 47.4% of the WB studied populations, the existence of hunting pressure on the population
was specified. However, in 1.9% of them hunting was not allowed, for instance, due to protection
regimes of the study area. Moreover, in at least 28.1% of the analysed WB populations, the use
of supplementary feeding was noticed, in most cases for hunting purposes or to mitigate crop
damages. In other cases, these parameters were not indicated.
3.2. Density, population structure and aggregation parameters
In relation to WB density (N=299 density values collected from literature), the mean value was
4.8 (± 5.1) wild boars/km2 at European level. However, this value fluctuated strongly among
bioregions. Mean density for South (N=126) bioregion was 6.0 (±5.1) wild boars/km2; whereas
for West (N=73), mean density was 5.8 5.7) wild boars/km2. East (N=96) and North (N=2)
bioregions showed the lowest mean density values, with 2.4 (± 3.7) and 1.0 wild boars/km2
(standard deviation not available due to low sample size), respectively.
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
In general, sex ratio (males:females; N=129) was 1.0 (±0.4), ranging from 0.4 to 3.4. By
bioregions, sex ratio at East (N=7) was 1.0 (±0.4), at North (N=3) was 1.6 (SD not available), at
South (N=51) was 1.0 (±0.6), and at West was (N=68) 1.0 (±0.2).
By age structure, WB juveniles (N=123) represented 35.5 (±17.5) % of the total population, 31.9
(±15.1) % yearlings (N=101), and 37.6 (±16.1) % adults (N=100). Generally, these parameters
are extracted from harvested WBs, so these parameters values may be affected when
hunting/culling activity were not randomly developed (e.g., hunters preference, control strategy).
Aggregation data searched in articles showed mean group size (N=8) of 4.1 (±2.1) individuals
but may vary among seasons. Female group (including offspring, N=5) averaged 2.9 (±3.9) WB.
Table 8 shows the average value, range, and standard error of each parameter.
Table 8. Density, population structure and aggregation average values (N is indicated within
parenthesis). Average (range, SE).
Local density (ind/km2) (299)
4.8 (0-32, 5.1)
Winter local density (ind/km2) (16)
2.7 (0-11.2, 2.7)
Spring local density (ind/km2) (20)
6.6 (0-21.4, 6.1)
Summer local density (ind/km2) (20)
28.4 (0-72.9, 25.7)
Autumn local density (ind/km2) (20)
20.1 (0-52.8, 20.7)
Carrying capacity (K, ind/km2) (1)
19.6 (2)
Sex ratio (males:females)
Foetus (14) = 1.0 (0.6-1.5, 0.3)
Juvenile (25) = 0.9 (0.4-1.3, 0.3)
Yearling (25) = 1.3 (0.5-2.8, 0.5)
Adult (38) = 1.4 (0.3-14.0, 2.4)
Population (age not specified) (129) = 1.0 (0.4-3.7, 0.4)
Age structure
Juvenile male (43) = 20.4 (6.8-46.8, 9.4)
Yearling male (52) = 16.7 (2.9-81.8, 12.4)
Adult male (71) = 15.3 (1.1-44.4, 9.0)
Male (age not specified) (27) = 44.8 (4.1-75.0, 17.9)
Juvenile female (54) = 22.7 (4.6-53.2, 10.8)
Yearling female (62) = 19.0 (3.8-68.4, 13.0)
Adult female (88) = 19.7 (1.0-80.0, 12.5)
Female (age not specified) (26) = 43.3 (2.7-68.0, 16.7)
Juvenile (age not specified) (123) = 35.5 (0.0-88.2, 17.5)
Yearling (age not specified) (101) = 31.9 (1.4-77.9, 15.1)
Adult (age not specified) (100) = 37.6 (2.7-79.2, 16.1)
Group size (number of individuals)
Male (NA)
Female (maternal groups) (5) = 3.0 (1.0-10.0,3.9)
Population (spring) (7) = 4.8 (3.9-7.4, 1.6)
Population (summer) (7) = 4.6 (3.4-6.8, 1.0)
Population (Autumn) (8) = 4.1 (2.5-5.7, 0.9)
Population (Winter) (7) = 3.4 (2.4-5.7, 1.1)
Population (Year) (8) = 4.1 (1.6-8.7, 2.1)
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
3.3. Average body weight by sex an age group
The average body weights by sex an age group are indicated in Table 11.
Table 11. Body weight average values (N is indicated within parenthesis). Average (range, SE).
Juvenile male (7) = 25.3 (8.7-30, 7.4)
Yearling male (8) = 53.4 (29.0-86.8,17.6)
Adult male (22) = 79.3 (39-133, 21.0)
Male (age not specified) (8) = 55.4 (39.4-71.3, 12.3)
Juvenile female (10) = 30.3 (8.9-40.9, 9.6)
Yearling female (12) = 56.1 (28.0-69.4, 14.2)
Adult female (28) = 67.6 (29-112.5, 19.0)
Female (age not specified) (11) = 45.0 (32.0-64.2, 11.6)
Juvenile (sex not specified) (20) = 34.4 (7.5-64.9, 15.9)
Yearling (sex not specified) (18) = 41.2 (13.6-82.0, 19.7)
Adults (sex not specified) (11) = 65.0 (17.9-114.5, 27.9)
Population (22) = 47.5 (34.0-80.0, 10.5)
3.4. Mortality (survival) by sex and age group
The mortality (survival) parameters by sex and age group are shown in Table 12.
Table 12. Mortality (annual %, N is indicated within parenthesis). Average (range, SE).
Natural: by predator
Juvenile male (NA)
Yearling male (NA)
Adult male (NA)
Male (age not specified) (NA)
Juvenile female (NA)
Yearling female (NA)
Adult female (NA)
Female (age not specified) (NA)
Juvenile (sex not specified) (1) = 13.5 (NA)
Population (age and sex not specified) (11) = 13.9 (2-63, 17.5)
Natural: by disease
Juvenile male (NA)
Yearling male (NA)
Adult male (NA)
Male (age not specified) (NA)
Juvenile female (NA)
Yearling female (NA)
Adult female (NA)
Female (age not specified) (NA)
Juvenile (age not specified) (NA)
Population (age and sex not specified) (1) = 30.0 (NA)
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Other: road kills
Juvenile male (NA)
Yearling male (NA)
Adult male (NA)
Male (age not specified) (NA)
Juvenile female (NA)
Yearling female (NA)
Adult female (NA)
Female (age not specified) (1) = 13.0 (NA)
Juvenile (age not specified) (NA)
Population (age and sex not specified) (6) = 11.1 (0.9-26.0, 10.0)
Natural mortality
Juvenile male (8) = 16.5 (6.0-35.2, 11.4)
Yearling male (9) = 19.9 (5.4-39.1, 13.4)
Adult male (6) = 13.7 (1.0-1.7, 15.0)
Male (age not specified) (2) = 15.0 (NA)
Juvenile female (8) = 29.6 (7.1-84.0, 26.0)
Yearling female (7) = 24.9 (11.7-43.4, 11.4)
Adult female (13) = 31.1 (1.6-90.0, 25.3)
Female (age not specified) (1) = 13.0 (NA)
Juvenile (age not specified) (8) = 40.4 (6.0-90.0, 25.3)
Yearling (age not specified) (2) = 75.0 (NA)
Population (age and sex not specified) (13) = 35.5 (1.7-100, 33.6)
By harvest
Juvenile male (20) = 24.6 (4.4-56.0, 13.0)
Yearling male (22) = 35.5 (2.5-77.0, 30.2)
Adult male (24) = 43.2 (10.5-76.0, 26.2)
Male (age not specified) (3) = 45.5 (19.0-70.0, 25.6)
Juvenile female (19) = 19.8 (2.0-44.0, 10.5)
Yearling female (21) = 30.4 (1.0-70.0, 25.1)
Adult female (21) = 38.5 (6.0-70.0, 21.1)
Female (age not specified) (3) = 43.2 (39.0-50.7, 6.5)
Juvenile (age not specified) (18) = 25.8 (0.0-60.0, 16.7)
Yearling (age not specified) (18) = 43.7 (20.0-68.4, 13.0)
Adult (age not specified) (19) = 43.2 (2.1-100.0, 28.7)
Population (age and sex not specified) (64) = 56.0 (1.7-100, 26.0)
Mortality (natural + harvest)
Juvenile male (1) = 74.2 (NA)
Yearling male (NA)
Adult male (NA)
Male (age not specified) (NA)
Juvenile female (1) = 48.2 (NA)
Yearling female (1) = 56.8 (NA)
Adult female (NA)
Female (age not specified) (NA)
Juvenile (age not specified) (NA)
Yearling (age not specified) (NA)
Adult (age not specified) (NA)
Population (age and sex not specified) (14) = 27.5 (9.4-64.0,
16.1)
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
3.5. Reproduction
Reproduction parameters are summarized in Table 13.
Table 13. Reproduction and productivity (N is indicated within parenthesis). Average (range,
SE).
Litter size
Juvenile (2) = 2.8 (1.6-4.0, 1.7)
Yearling (5) = 3.6 (1.5-6.0, 1.8)
Adult (4) = 5.5 (4.1-6.3, 1.0)
Female (age not specified) (27) = 4.2 (0.4-7.0, 1.5)
Foetus/juvenile female (14) = 3.5 (2.0-4.9, 0.8)
Foetus/yearling female (30) = 5.0 (1.2-7.0, 1.1)
Foetus/adult female (27) = 5.9 (3.3-9.0, 1.1)
Foetus/female (7) = 4.6 (3.5-6.2, 0.9)
Pregnant female (proportion, %)
Juvenile (35) = 25.6 (0.0-73.0, 18.8)
Yearling (33) = 42.7 (1.0-100, 23.6)
Adult (36) = 49.8 (4.0-100, 33.2)
Female (age not specified) (17) = 50.9 (17.7-86.0, 24.4)
Seasonality of reproduction (% of pregnant
by month)
January (6) = 48.3 (2.5-80.0, 34.8)
February (5) = 51.9 (16.5-80.0, 32.2)
March (3) = 48.7 (35.0-65.0, 15.2)
April (3) = 30.5 (16.5-55.0, 21.3)
May (3) = 30.5 (0.0-55.0, 30.4)
June (3) = 20.3 (3.0-55.0, 30.0)
July (3) = 8.2 (2.0-18.0, 8.6)
August (4) = 16.6 (2.5-43.0, 19.0)
September (4) = 14.4 (3.5-31.0, 1.9)
October (4) = 23.9 (0.0-70.0, 32.2)
November (6) = 42.0 (0.0-80.0, 39.0)
December (5) = 37.6 (2.0-80.0, 39.5)
3.6. Spatial dispersal parameters
Average values on spatial dispersal parameters are summarized in Table 14.
Table 14. Movement average values (N is indicated within parenthesis). Average (range, SE).
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Dispersion: maximum distance (km)
Juvenile Male (2) = 14.3 (NA)
Yearling Male (5) = 54.0 (1.9-250; 109.6)
Adult Male (1) = 24.2 (NA)
Male (age not specified) (1) = 6.0 (NA)
Juvenile Female (2) = 250.4 (NA)
Yearling Female (2) = 11.5 (NA)
Adult Female (2) = 3.1 (2.5-3.7, 0.9)
Female (age not specified) (2) = 3.7 (2.5-4.9, 1.7)
Juvenile (sex not specified) (1) = 60 (NA)
Yearling (sex not specified) (3) = 2.3 (1.0-4.0, 1.5)
Adult (sex not specified) (1) = 0.2 (NA)
Population (12) = 12.0 (0.9-40.0, 11.9)
Proportion of dispersants (%)
Male (1) = 42.0 (NA)
Female (1) = 16.0 (NA)
Home range (50 & 95% Kernel polygon, km2)
Male (50%) (3) = 4.6 (1.4-11.1, 5.6)
Male (95%) (1) = 8.7 (NA)
Maternal group (50%) (3) = 0.2 (0.0-0.2, 0.1)
Maternal group (95%) (8) = 3.3 (0.2-12.3, 4.0)
Population (95%) (9) = 4.4 (2.0-14.1, 3.7)
Population (50%) (1) = 0.8 (NA)
Home range (minimum convex polygon, km2)
Juvenile male (NA)
Yearling male (1) = 1.0 (NA)
Adult male (4) = 4.5 (0.7-10.1, 4.5)
Male (age not specified) (NA)
Juvenile female (2) = 23.5 (NA)
Yearling female (2) = 6.2 (NA)
Adult female (4) = 2.9 (0.5-7.6, 3.3)
Female (age not specified) (1) = 0.4 (NA)
Juvenile (sex not specified) (1) = 0.5 (NA)
Yearling (sex not specified) (1) = 23.5 (NA)
Population (14) = 4.6 (0.5-12.6, 3.7)
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
4. Conclusions and further steps
Beyond the collection of current available data, we provided an open data model to allow
academics and wildlife professionals to continuously update population parameters with
new and/or hardly accessible data (i.e., grey literature which is not public or only available
in local languages). This data model, understood as an open resource and collaborative
approach, has been incorporated to the European Observatory of Wildlife (EOW) website
(https://wildlifeobservatory.org/).
To overcome the lack, or the availability of only unharmonized information, our data
model includes several potential drivers and population parameters that should be
specified in every study on WB (and wildlife in general) ecology and epidemiology at the
proper spatio-temporal resolution.
Even when we mostly focused on recent data (mainly from 2010 onwards), the temporal
frame of available data does not always represent the current situation. WB populations
have been increasing during the last decade in the absence of ASF, and in certain regions
the direct impact of ASF and/or reactive and proactive policies have led to very different
scenarios.
The immediate potential impact of making available the information here reviewed on
WB ecological and population dynamics parameters for ASF management in the EU are
(i) better understanding the impact of ASF and ASF-management on WB populations and
(ii) to identify gaps areas or management contexts to plan integrated and harmonized
monitoring of WB population dynamics trends, so as the better strategy (e.g., EOW). In
addition, (iii) reliable parameters are now available to feed population dynamics and
epidemiological models.
Next steps we identified are:
o This harmonized approach of collection on WB population dynamics parameters
should extend to other taxa as an essential tool to improve European capacities
to monitor, to produce risk assessment and to manage wildlife under an
international perspective. The EOW aims hosting a virtual space in the web and
promote this activity among wildlife professionals and academics.
o To promote the use of common standards to record and publish ecological and
population dynamics parameters.
o To continue data collection in the case of WB, also identifying sources from the
grey literature.
Wild boar ecology
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21
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
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scale. EFSA Supporting Publication 2021:EN-6825. 30pp. doi:10.2903/sp.efsa.2021.EN-6825
Massei G, Roy S, Bunting R, 2011. Too many hogs? A review of methods to mitigate impact by
wild boar and feral hogs. Human-Wildlife Interactions, 5, 79-99.
Pittiglio C, Khomenko S, Beltran-Alcrudo D, 2018. Wild boar mapping using population-density
statistics: From polygons to high resolution raster maps. PLoS ONE 13(5): e0193295
Pullin AS, Knight TM, 2009. Data credibility: A perspective from systematic reviews in
environmental management. M. Birnbaum, P. Mickwitz (Eds), Environmental program and
Wild boar ecology
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22
EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
policy evaluation: Addressing methodological challenges. New Directions for Evaluation, pp
122: 65-74.
Vetter SG, Puskas Z, Bieber C, Ruf T, 2020. How climate change and wildlife management affect
population structure in wild boars. Scientific Reports, 10, 1-10.
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Annex A Studies on basic aspects of wild boar population dynamics
all over Europe
Table S1. Key review papers and reports describing the basic aspects of wild boar population
dynamics all over Europe(a).
Type of
parameter
Parameter
Spatial context
Observations
Ref
Population
characteristic
Density
(wb/km2)
West and
Central Europe
Ranged from 1.2 to 90.9(b)
based mostly on not reliable
data.
Acevedo et al. 2007;
Ruiz-Fons et al. 2008
Population
characteristic
(Hunting)
Growth rate
Europe
Growth rate varied from 0.9 to
1.46, based on hunting bag
statistics
Massei et al. 2015
Population
characteristic
(Hunting)
Growth rate
West Europe
(Spain)
Growth rate varied from 2.1 to
40.3, based on hunting bag
statistics
Quirós-Fernández et
al. 2017
Population
characteristic
Growth rate
West and
Central
Europe, and
Asia
Based on projection matrix
models, growth rate varied from
0.85 to 1.63.
Bieber and Ruf, 2005
Mortality
By harvest
Central Europe
Based on hunted tracked WB,
average mortality rate was 0.53.
Keuling et al. 2013
Mortality
By harvest and
disease
West Europe
(Spain)
Average mortality rate was 0.53
by harvest; and 0.30 by disease
(tuberculosis).
Barasona et al. 2016
Reproductive
Litter size
Europe
Mean ranged from 3.58 to 6.5.
Bieber and Ruf, 2005
Reproductive
Litter size
West and
Central Europe
Mean ranged from 2.2 to 4.
Rosell et al. 2001
Reproductive
Litter size
Europe
Mean ranged from 3.6 to 7.6
Fonseca et al. 2011
Reproductive
Litter size
West and
Central Europe
Mean ranged from 3.1 to 6.9.
Bywater et al. 2010
Spatial
behaviour
-
Global
Research tendencies and gaps,
no values provided.
Morelle et al. 2014;
Morelle and Lejeune,
2015
(a): Extensive literature is also available for feral pig population dynamics, especially in the USA, but of very low
application to our cases.
(b): This value is reached under artificial conditions, such as fenced game estates with artificial feeding.
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has
been carried out exclusively by the authors in the context of a contract between the European Food Safety
Authority and the authors, awarded following a tender procedure. The present document is published complying
with the transparency principle to which the Authority is subject. It may not be considered as an output adopted
by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues
addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.
Table S2. The main drivers identified on publications that could influence significantly on WB
population dynamics.
Type of driver
Driver
Observations
Ref
Interspecific
interactions
Predation
Lack of top-down control can favour
population growth.
Bassi et al. 2020;
Jędrzejewski et al. 1992;
Segura et al. 2014
Diseases & parasites
Effects on survival, reproductive or
mortality rates.
Barasona et al. 2016; Ruiz-
Fons et al. 2008
Landscape
Land use change
Easier food access or the increment of
available and favourable habitat could
contribute on WB population growth.
Acevedo et al. 2011; Hearn
et al. 2014; Kodera et al.
2010
Urban expansion
Rural abandonment
Climatic
Global warming
Favourable climatic conditions in-
creasing winter survival and food
availability throughout the year.
Bieber and Ruf, 2005;
Melis et al. 2006; Vetter et
al. 2020; Vetter et al. 2015
Drought episodes
Effect on reproductive performance.
Fernández-Llario and Car-
ranza, 2000
Food availa-
bility
Productivity
Related with climatic conditions.
Barbosa et al. 2020;
Frauendorf et al. 2016
Supplementary
feeding
Associated with higher recruitment
rate and litter size.
Massei et al. 2015
Management
Hunting
Hunting induce mortality and affects
WB dynamic. A decrease in the num-
ber of hunters, difficult population
management.
Cromsigt et al. 2013; Hol-
land et al. 2009; Merli et al.
2017
Conservation or ag-
roforestry policy
Differential effect on population dy-
namic among different applied poli-
cies.
Vicente et al. 2005
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has been carried out exclusively by the authors in the context of a contract between
the European Food Safety Authority and the authors, awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority
is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the
conclusions reached in the present document, without prejudice to the rights of the authors.
Table S3. Parameters describing the basic aspects of WB population dynamics relevant to understanding disease dynamics and improve science-based ASF
management. Colours of “trait” column indicate the priority of each parameter to be determined (orange: high; yellow: medium; green: low).
Population pa-
rameters
Trait
Sex by age class
Temporal
Spatial reso-
lution
Units
Why is important?
Ref
Population
characteris-
tics
Local density
Optimally pre-har-
vest season
(for standardiza-
tion)
Manage-
ment or
ecological
unit
ind/km2 or
social
group/km2
- Disease transmission is a density-dependent process.
Population and individual traits are density dependent.
Management is based on numbers (abundance indexes
are not sufficient or comparable)
- It could further elucidate complex species-habitat-man-
agement relationships in spatial distribution models
KramerSchadt et
al. 2009
Absolute
abundance
Nº individu-
als
Yu et al. 2020
Carrying ca-
pacity
Lowest over the
year
Ecological
unit
maximum
population
size or den-
sity (
K
)
- Variable due to habitat perturbations and environmental
factors (e.g., resource availability and climate). Theoret-
ically, maximum productivity (i.e., population growth
rate) is achieved when the population is approx. 50% of
the K (basic logistic growth models). Useful for model-
ling scenarios of potential population growth and conse-
quences for disease spread, maintenance and control.
Groot Bruinderink
et al. 1994
Sex ratio
juvenile (< 1
y)
Optimally pre-har-
vest season
(for standardiza-
tion)
Manage-
ment or
ecological
unit
ff:mm
- Essential to rebuild population structure and model pop-
ulation dynamics
- Influence on the spatial behaviour and interactions
among social units (groups) and modulate the spread of
infectious diseases
- Each sex by age class has distinct properties in terms of
their demographic and infection dynamics
- Key parameters to define population control strategy
- These parameters are among those presenting larger
variation over geographical distribution and manage-
ment
Hema et al. 2020;
Mortensen et al.
2016
yearling (1-2
y)
adult (> 2 y)
Group size
male
average annual
and by month or
season
mean num-
ber of indi-
viduals, as-
sumed 1
Loehle, 1995; Pe-
pin et al. 2020;
Podgórski et al.
2018
maternal
groups
mean num-
ber of indi-
viduals
Age structure
By sex
Pre-harvest sea-
son
%
Hoy et al. 2020
Wild boar ecology
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has been carried out exclusively by the authors in the context of a contract between
the European Food Safety Authority and the authors, awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority
is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the
conclusions reached in the present document, without prejudice to the rights of the authors.
Population
growth rate
yearly
% or in-
crease rate
(r)
Fonseca et al.
2011
Recruitment
rate
coefficient
of
young/adult
DeCesare et al.
2012
Population
characteris-
tics: mortal-
ity
Natural: pre-
dation/
disease
Sex by age.
Especially on
piglets (<3
months old)
yearly
% mortality
(1/survival)
Bassi et al. 2020;
Keuling et al.
2013; Lange et al.
2012; Merli et al.
2017; Tanner et
al. 2019b
By harvest
Other: e.g.,
road kills
Reproduction
(productivity)
Litter size
By age*
yearly
Number of
offspring
born by fe-
male age
class
Fernández-Llario
& Mateos-Que-
sada, 1998;
Frauendorf et al.
2016
Pregnant fe-
males
yearly and
monthly
% of fe-
males be-
coming
pregnant
by age
class
Fernández-Llario
& Mateos-
Quesada, 2005;
Lombardini et al.
2014
Spatial be-
haviour
Proportion of
dispersants
Sex by age
yearly
%
- Related with species geographical and disease disper-
sion.
- Spatial behaviour determines interactions (within and
among groups)
- Spatial behaviour is relevant to implement effective
management strategies.
- Influenced by land uses and human activities among
other factors, including population control and response
to ASF
Casas-Díaz et al.
2013; Truvé & Le-
mel, 2003; Truvé
et al. 2004
Dispersal pe-
riod
Sex by age
month/sea-
son
Dispersal dis-
tance
km
Home range
(50 & 95%K)
Sex by age
(males, mater-
nal groups)
seasonal
km2
Bisi et al. 2018;
Keuling et al.
2008
Modelling wild boar distribution and abundance
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EFSA Supporting publication 2022:EN-7211
The present document has been produced and adopted by the bodies identified above as authors. This task has been carried
out exclusively by the authors in the context of a contract between the European Food Safety Authority and the authors,
awarded following a tender procedure. The present document is published complying with the transparency principle to which
the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority
reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document,
without prejudice to the rights of the authors.
Preprint
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