Predation and Disease Related Economic Impacts of Feral Swine on Livestock Producers

University of Nebraska - Lincoln

DigitalCommons@University of Nebraska - Lincoln
USDA National Wildlife Research Center - Staff
Publications

U.S. Department of Agriculture: Animal and Plant
Health Inspection Service

2019

Predation and disease-related economic impacts of
wild pigs on livestock producers in 13 states
Aaron M. Anderson
APHIS, [email protected]

Chris Slootmaker
USDA APHIS Wildlife Services

Erin Harper
USDA/APHIS/WS National Wildlife Research Center

Ryan S. Miller
USDA APHIS, [email protected]

Stephanie A. Shwiff
USDA, APHIS, Wildlife Services, National Wildlife Research Center, [email protected]

Follow this and additional works at: https://digitalcommons.unl.edu/icwdm_usdanwrc
Part of the Natural Resources and Conservation Commons, Natural Resources Management and
Policy Commons, Other Environmental Sciences Commons, Other Veterinary Medicine Commons,
Population Biology Commons, Terrestrial and Aquatic Ecology Commons, Veterinary Infectious
Diseases Commons, Veterinary Microbiology and Immunobiology Commons, Veterinary
Preventive Medicine, Epidemiology, and Public Health Commons, and the Zoology Commons
Anderson, Aaron M.; Slootmaker, Chris; Harper, Erin; Miller, Ryan S.; and Shwiff, Stephanie A., "Predation and disease-related
economic impacts of wild pigs on livestock producers in 13 states" (2019). USDA National Wildlife Research Center - Staff Publications.
2250.
https://digitalcommons.unl.edu/icwdm_usdanwrc/2250

This Article is brought to you for free and open access by the U.S. Department of Agriculture: Animal and Plant Health Inspection Service at
DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USDA National Wildlife Research Center - Staff Publications
by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln.

Crop Protection 121 (2019) 121–126

Contents lists available at ScienceDirect

Crop Protection
journal homepage: www.elsevier.com/locate/cropro

Predation and disease-related economic impacts of wild pigs on livestock
producers in 13 states
Aaron Anderson a, *, Chris Slootmaker a, Erin Harper a, Ryan S. Miller b, Stephanie A. Shwiff a
a

USDA/APHIS/WS National Wildlife Research Center, 4101 Laporte Avenue, Fort Collins, 80521, Colorado, USA
USDA Animal Health Plant Inspection Service, Center for Epidemiology and Animal Health, Natural Resource Research Center, 2150 Centre Ave. Bldg B-2W68, Fort
Collins, 80526-8117, Colorado, USA

b

A R T I C L E I N F O

A B S T R A C T

Keywords:
Wild pigs
Invasive species
Livestock predation
Livestock disease
Survey

We report the results of a survey on wild pigs (Sus scrofa) damage to livestock producers in 13 US states (Ala­
bama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, South
Carolina, Tennessee, Texas). The survey was distributed by the USDA National Agricultural Statistical Service in
the summer of 2017 to a sample of livestock producers in the 13-state region. Findings indicate that predation
and disease-related damage can be substantial in certain states and for certain types of livestock. In particular,
damage to cattle operations in Texas and Arkansas was substantially higher than damage in other states and
types of livestock operations. When extrapolated to livestock producers across the entire 13-state region, we
estimated that damages sum to an annual cost of about $40 million. We hope findings from this survey will help
guide control efforts and research, as well as serve as a benchmark against which the effectiveness of future
control efforts can be measured.

1. Introduction
Wild pigs (Sus scrofa) have become widespread throughout much of
the United States because of their reproductive potential, adaptable
biology, and relocation by humans. (Seward et al., 2004). Over the past
30 years, the range of wild pigs has increased from 17 to 38 states
(Bevins et al., 2014) (Fig. 1). The recent range expansion of wild pigs has
inflicted substantial costs on agricultural producers in the United States.
Though estimates of damage to agricultural production range widely
and are largely context specific (Bevins et al., 2014), it is clear that wild
pigs have the ability to damage most crops, destroy livestock through
disease and depredation, compete with native wildlife, and effectively
destroy ecosystems (Barrios-Garcia and Ballari, 2012; Crooks, 2002).
With the recent range expansion of wild pigs across much of the
United States, an understanding of the economic and environmental
impacts caused by this non-native invasive species has continued to
develop. While much work has focused on wild pig impacts specific to a
local geographic region or individual resource, some aggregate esti­
mates of damage have been published. As an example of the latter, the
widely cited estimates of invasive species impacts reported by Pimentel
et al. (2005) include an estimate of country-wide wild pig damage in the
US of $800 million annually. More specific analyses of wild pig impacts

include effects of rooting in floodplains (Arrington et al., 1999), impacts
on plant species richness (Hone, 2002), and depredation of invertebrates
in wetlands (Doup�e et al., 2010).
Recent efforts have been made to produce more rigorous estimates of
wild pig impacts at aggregated levels. Regarding crop damage to major
US crops, Anderson et al. (2016) estimates annual crop loss from wild
pig damage of $190 million annually to corn, soybeans, wheat, rice,
peanuts, and sorghum in 11 states. Impacts to livestock production have
also been highlighted due to the potential for disease spread and impacts
on international trade of related products (Miller et al., 2017). While it is
accepted that wild pigs impose significant impacts on domestic livestock
production via depredation and disease (Bevins et al., 2014), aggregate
estimates analogous to those of Anderson et al. (2016) do not exist.
This manuscript summarizes a recent survey-based effort to fill in
this gap. We proceed with a discussion of the survey instrument, survey
distribution, and rules related to disclosure of information. Results are
then presented with a focus on two key objectives: 1) wild pigs gaining
access to livestock production areas and facilities, and 2) the types and
severity of damages that livestock producers experienced. We addi­
tionally examined how the findings related to these objectives varied
across states and types of livestock operations. Presentation of the re­
sults is followed by a discussion of their implications. Ultimately, the

* Corresponding author.
E-mail address: [email protected] (A. Anderson).
https://doi.org/10.1016/j.cropro.2019.03.007
Received 6 November 2018; Received in revised form 8 March 2019; Accepted 15 March 2019
Available online 20 March 2019
0261-2194/© 2019 Published by Elsevier Ltd.
This document is a U.S. government work and
is not subject to copyright in the United States.

A. Anderson et al.

Crop Protection 121 (2019) 121–126

Fig. 1. Wild pig distribution in 1982 and 2015.

from wild pigs and related concerns, as well as pasture damages, pro­
ducers were asked about livestock loss from wild pig depredation, dis­
ease, and other causes. Additionally, they were asked to report costs of
medical treatments and veterinary services related to wild pig contact
with their livestock. Producers that failed to respond to the initial
mailing received multiple follow-up phone calls in an attempt to mini­
mize non-response bias, and a total of 6,394 responses were obtained.
In this manuscript, we focused on two types of information collected
by the survey. The first is the presence of wild pigs. Wild pig presence
provides a general indication of the economic threat they pose in the
area, either through direct damage or the risk of disease transmission.
We solicited information on presence by asking two general questions
regarding wild pig presence in the producer’s county and on their
operation (Fig. 2). Additionally, we asked questions about wild pigs
gaining access to areas where livestock were being kept (Fig. 3). Finally,
as a follow-up questions, we asked the producer to report how frequently
access is occurring.
In addition to our interest in the presence and the frequency of
gaining access to livestock areas, our other focus was on the perceived
damages by wild pigs. We used a series of questions to solicit informa­
tion regarding damages from producers in 2016 (Fig. 4). Specifically we
asked about losses due to predation, disease, and unknown causes (e.g.
undetermined, stress), as well as costs related to veterinary services (e.g.
paying a veterinarian) and medical treatments (e.g. drugs costs).
Despite the potential inaccuracies associated with relying on selfreported damages, we chose this design for several reasons. First, selfreporting of wildlife damages to agriculture is common and has been

information we present may enhance the efficiency of producer and
government led control efforts by allowing resources to be allocated to
the most severe problems. Furthermore, this type of information could
serve as a baseline against which the effects of future control efforts
could be measured.
2. Methods
In order to obtain representative estimates of livestock impacts and
costs of wild pigs at the state level, the US Department of Agriculture’s
(USDA) National Agricultural Statistical Service (NASS) distributed a
survey designed by researchers at the USDA’s National Wildlife
Research Center. Targeted operations included producers of cattle (beef
and dairy operations), swine, sheep, and goats. Following the 2015
survey of crop producers reported in Anderson et al. (2016), livestock
producers in the same 11 states (Alabama, Arkansas, California, Florida,
Georgia, Louisiana, Mississippi, Missouri, North Carolina, South Car­
olina, and Texas) were sampled, as well as Tennessee and Oklahoma,
both of which are major producers of the targeted commodities and have
wild pigs. States were ultimately selected by a subjective evaluation of
economic importance (United States Department of Agriculture, 2014),
vulnerability to feral swine (see Fig. 1), and political considerations.
The survey instrument was designed to elicit a range of values
associated with wild pig presence. Although tailored in part to specifics
of livestock production, the survey also collected information on crop
impacts, property damages, control costs, and sport hunting practices. In
addition to operation-wide questions regarding potential disease spread

Fig. 2. Survey questions related to wild pig presence in the area.
122

A. Anderson et al.

Crop Protection 121 (2019) 121–126

Fig. 3. Survey questions related to wild pig presence on the operation and their impact on the two highest-valued livestock types that were on the operation.

Fig. 4. Questions related to wild pig damages to the two highest-valued livestock types that were on the operation.

shown to be quite accurate (Conover, 2002; Johnson-Nistler et al., 2005;
Tzilkowski, 2002; Wywialowski, 1994). Second, livestock values can
vary substantially according to region and type of livestock (even within

specific categories). We believed it preferable to rely on producers that
have first-hand knowledge of values and prices rather than making an
assumption based on potentially crude pricing statistics. Finally, even if
123

A. Anderson et al.

Crop Protection 121 (2019) 121–126

Table 1
Wild pig presence in the last three years by state.
In County
Alabama
Arkansas
California
Florida
Georgia
Louisiana
Mississippi
Missouri
North Carolina
Oklahoma
South Carolina
Tennessee
Texas
Total

Table 3
Producers reporting wild pigs had gained access to areas where livestock are
kept.

On Operation

Yes

No

Don’t Know

Yes

No

Don’t Know

49%
64%
44%
65%
54%
73%
66%
19%
28%
75%
61%
30%
88%
61%

32%
21%
38%
23%
33%
17%
24%
58%
49%
14%
26%
51%
7%
26%

19%
15%
18%
11%
14%
11%
11%
24%
23%
11%
13%
19%
4%
13%

17%
33%
21%
34%
26%
37%
24%
5%
7%
46%
27%
7%
68%
37%

79%
63%
77%
62%
70%
60%
71%
92%
88%
50%
68%
89%
31%
60%

4%
4%
2%
4%
4%
3%
6%
3%
5%
5%
5%
4%
2%
3%

Alabama
Arkansas
California
Florida
Georgia
Louisiana
Mississippi
Missouri
North
Carolina
Oklahoma
South
Carolina
Tennessee
Texas
Total

Table 2
Wild pig presence on operations in the last three years by type.
Beef Cows
Milk Cows
Other Cattle
Domestic Pigs
Sheep and Lambs
Goats and Kids
Poultry
Equine
Other
Total

Yes

No

Don’t Know

41%
40%
43%
39%
28%
29%
36%
42%
44%
40%

56%
59%
54%
58%
69%
68%
62%
55%
52%
57%

3%
1%
3%
3%
4%
3%
2%
3%
4%
3%

FS Had
Gained
Access

Frequency Seen (if present)
Daily

Weekly

About once
a month

Less than
once a month

8%
23%
18%
25%
14%
27%
15%
3%
2%

29%
23%
27%
25%
22%
18%
11%
0%
22%

32%
30%
27%
22%
31%
37%
28%
40%
22%

19%
21%
22%
29%
24%
22%
40%
1%
0%

20%
22%
20%
23%
24%
19%
16%
59%
57%

38%
15%

32%
24%

29%
20%

20%
25%

17%
26%

4%
60%
30%

0%
34%
31%

0%
26%
27%

40%
24%
24%

60%
14%
17%

Table 4
Producers reporting wild pigs had gained access to where livestock are kept.
FS Had
Gained
Access
Beef Cows
Milk Cows
Other Cattle
Domestic
Pigs
Sheep and
Lambs
Goats and
Kids
Poultry
Equine
Other
Total

producer perceptions are not entirely accurate, the perception them­
selves are important to consider given that production and control de­
cisions are based on these perceptions.
3. Results
A total of 12,000 surveys were administered by NASS, with a
response rate of 53%, for a total of 6,394 responses. In order to produce
estimates of wild pig impacts at the state level, NASS calculates weights
that account for state-wide production of each commodity. Additionally,
individual level responses are weighted to account for non-response by
other producers. These producer-level weights were used and adjusted
accordingly for non-response of specific questions, leaving estimates of
wild pig damages representative at the state level. In cases where either
a single producer made up a large portion of responses to a specific
question or only a few producers responded to it, values are not dis­
closed in order to protect the private information of producers. At the
state level, these disclosure requirements are largely unrestrictive in
terms of limiting presentable results. Analysis of survey responses at the
more disaggregated level of livestock types within states is not as im­
mune to disclosure concerns and is therefore unreported here.
A majority (61%) of counties in most of the surveyed states are
believed to have had wild pigs in the last three years (Table 1). Addi­
tionally, over a third (37%) of the targeted livestock producers in these
states reported wild pigs on their operation during this period. The re­
ported belief that wild pigs are present in the county or on the operation
are highest in Texas (88%/68%) and Oklahoma (75%/46%) and lowest
in Missouri (19%/5%) and North Carolina (28%/7%). In addition to
summarizing presence at the state level, we also calculated the percent
of responses that reported presence on their operation by livestock type
(Table 2). Note that producers may report on more than one livestock
type for their operation. Thus, total values do not necessarily align when
comparing state-level and type-level calculations. The results indicate
that operations with cattle were most likely to report the presence of

Frequency Seen (if present)
Daily

Weekly

About once
a month

Less than
once a month

35%
33%
27%
29%

35%
10%
25%
4%

26%
36%
32%
1%

24%
11%
20%
7%

13%
43%
22%
77%

4%

34%

29%

0%

39%

20%

18%

16%

49%

18%

7%
13%
15%
30%

21%
0%
15%
31%

42%
6%
52%
27%

1%
59%
33%
24%

37%
34%
0%
17%

wild pigs, while sheep and goat operations were the least likely.
A primary concern stemming from the close proximity of wild pigs
and domestic livestock production is the potential for wild pigs to spread
disease to both animals and humans (Miller et al., 2017). Although wild
pigs may be present on many operations, the question of contact with
domestic animals is more specific. To this end, producers were asked if
wild pigs had gained access to areas where livestock were kept during
2016, and if so, how frequently wild pigs had been seen in these areas
(Table 3, Table 4). As these responses are specific to each (of up to two)
livestock types reported on, the state and type totals are the same.
Regarding a comparison across states, the results largely mirror the re­
sults presented in Table 1. Nearly 34% of Texas responses indicated that
wild pigs gain daily access to areas where livestock are kept. Signifi­
cantly, in nine (82%) of the states, responses indicate that wild pigs are
gaining daily access to areas where livestock are kept on over 20% of
operations.
Beef cattle operations are the most likely to report wild pigs gaining
access to areas where livestock are kept, while poultry and sheep and
lambs are the least likely to report access gained (Table 4). We suspect
that the differences observed in Table 4 are driven by several different
factors. First, there may be geographic effects. Certain types of opera­
tions may be more prevalent in areas with high wild pig density.
Additionally, biosecurity and the prevalence of large commercial oper­
ations probably plays a role. For example, large commercial cattle op­
erations may find it difficult to prevent wild pig access, but hobby farms
that raise small numbers of sheep, goats, or chickens may not have the
124

A. Anderson et al.

Crop Protection 121 (2019) 121–126

Table 5
Value of livestock deaths and medical expenditures due to wild pigs by state.
Alabama
Arkansas
California
Florida
Georgia
Louisiana
Mississippi
Missouri
North Carolina
Oklahoma
South Carolina
Tennessee
Texas
Total

Predation

Disease

Other Deaths

Veterinary Services

Medical Treatments

$349,950
$3,160,753
$19,193
$349,903
$154,919
$204,053
(D)
(D)
$0
$107,586
$126,089
$0
$12,794,578
$17,303,516

(D)
$0
(D)
$0
$59,872
(D)
(D)
$0
$0
$2,313,105
$27,437
$0
$6,711,569
$9,518,034

(D)
$2,810,725
$0
$823,390
$27,421
$151,646
(D)
$0
$0
(D)
$11,212
$0
$2,946,801
$7,003,548

$55,538
(D)
(D)
(D)
$46,717
(D)
(D)
$0
(D)
$301,242
$4,209
$0
$2,050,828
$2,641,853

$24,196
$1,428,871
$5,803
(D)
$46,492
$81,588
$0
(D)
(D)
$1,288,340
$10,308
$0
$543,673
$3,481,148

Table 6
Value of livestock deaths and medical expenditures due to wild pigs by livestock type.
Beef Cows
Milk Cows
Other Cattle
Hogs
Sheep
Goats
Poultry
Equine
Other
Total

Predation

Disease

Other Deaths

Veterinary Services

Medical Treatments

$8,111,869
(D)
$9,124,638
(D)
$0
$8,937
$0
(D)
$0
$17,303,516

$8,594,582
$0
(D)
$0
$0
(D)
$0
(D)
$0
$9,518,034

$6,069,188
(D)
$887,602
$0
(D)
(D)
$0
$0
$0
$7,003,548

$2,034,733
$0
(D)
(D)
$0
$0
$0
$0
$0
$2,641,853

$3,004,286
$0
$447,317
(D)
(D)
(D)
$0
$0
$0
$3,481,148

same difficulty if production occurs in small, easily enclosed areas.
Our primary objective was to collect information about economic
impacts and damages. To address this objective we calculated the annual
dollar value of livestock losses to predation, disease, and other deaths, as
well as veterinary and medical expenditures, as a result of wild pigs.
These values were calculated by state (Table 5) and livestock type
(Table 6). For reasons of disclosure described above, some categories of
damages cannot be reported. Such observations are given a “(D)”, which
means there may be positive loss in this category, but it cannot be re­
ported. These values should not be interpreted as a zero. For columns
where the value of more than one state or livestock type cannot be
disclosed, the total may still contain the undisclosed values, and there­
fore be different from the sum of the reported values in that column. This
also implies that the state-level estimates should be interpreted as lower
bounds on the true damages.
It is apparent from these results that predation is the most severe
impact to livestock producers. It is also clear that the majority of dam­
ages occur in Texas and Arkansas, while producers in many other states
suffer relatively little damage. Likewise, cattle producers suffer far more
damage that other livestock producers, largely as a result of the much
higher production value of cattle.

hindered by pig’s habit of consuming entire carcasses (Seward et al.,
2004). Finally, additional caution is warranted because our results are
based on self-reported damages.
Our results suggest that in the 13 states included in the study, wild
pigs are believed to be present in most of the sampled counties, and on
many of the operations sampled. Contact between wild pigs and do­
mestic animals is also common and highlights the potential danger wild
pigs pose in terms of disease transmission and other impacts. While the
costs of control efforts and other damages may be substantial, this report
summarizes only the direct costs in terms of deaths and medical ex­
penditures resulting from wild pig presence. For the group of targeted
producers in these 13 states, these damages sum to an estimated annual
cost of $39,948,099.1 Although the total estimated annual cost is not
large relative to the size of the industry in the surveyed states, our
findings have important implications. Damages appear to be heavily
concentrated in several states and among several types of livestock
producers. In fact, producers of most livestock types in most of the states
with wild pigs populations appear to be relatively unaffected by the
presence of wild pigs. This may result from relatively low swine density
in many areas, differences biosecurity and control efforts, or geographic
heterogeneity in the true nature of the threat posed by wild pigs.
We believe the results of our survey can serve two key purposes.
First, an understanding of which areas and livestock types experience
the most damage can help improve management efficiency. Producers
and government agencies expend considerable time and effort managing
wild pig damage, and knowing where the problem is most severe will
help these entities allocate their resources more appropriately. Second,
USDA/APHIS Wildlife Services has initiated a widespread feral swine
control campaign. In addition to guiding the implementation of this
program, the findings we present can serve as a benchmark for evalu­
ating this control program. Thus, our hope is that this survey can be
repeated at regular intervals to ensure that the objectives of the control

4. Discussion
Contact between wild pigs and domestic livestock imposes a poten­
tially wide range of costs on producers. These include losses of livestock
to predation and disease, expenditures on veterinary services and
medical treatments as a result of such contact, and costs of control ef­
forts to reduce contact. Additionally, damages to property, loss of crops,
rooting of pasture land, and damage to other farm resources (e.g. live­
stock waterers) may be significant (Bevins et al., 2014). In the present
analysis we have focused on only a few of the relevant impacts. Thus, the
total damages implied by our findings should be interpreted as a lower
bound on the true impacts of wild pigs on livestock producers. This is
reinforced by the fact accurate assessment of feral swine predation is

1

125

This is the sum of the totaled values in Table 5.

A. Anderson et al.

Crop Protection 121 (2019) 121–126

program are being met and progress is being made against the threat
that wild pigs represent to US agricultural producers.

Bevins, S.N., Pedersen, K., Lutman, M.W., Gidlewski, T., Deliberto, T.J., 2014.
Consequences associated with the recent range expansion of nonnative feral swine.
Bioscience 64 (4), 291–299.
Barrios-Garcia, M.N., Ballari, S.A., 2012. Impact of wild boar (Sus scrofa) in its
introduced and native range: a review. Biol. Invasions 14 (11), 2283–2300.
Conover, M., 2002. Resolving Human-Wildlife Conflicts: the Science of Wildlife Damage
Management. CRC Press, Boca Raton.
Crooks, J.A., 2002. Characterizing ecosystem-level consequences of biological invasions:
the role of ecosystem engineers. Oikos 97 (2), 153–166.
Doup�
e, R.G., Mitchell, J., Knott, M.J., Davis, A.M., Lymbery, A.J., 2010. Efficacy of
exclusion fencing to protect ephemeral floodplain lagoon habitats from feral pigs
(Sus scrofa). Wetl. Ecol. Manag. 18 (1), 69–78.
Hone, J., 2002. Feral pigs in Namadgi National Park, Australia: dynamics, impacts and
management. Biol. Conserv. 105 (2), 231–242.
Johnson-Nistler, C.M., Knight, J.E., Cash, S.D., 2005. Considerations related to
Richardson’s ground squirrel control in Montana. Agron. J. 97 (5), 1460–1464.
Miller, R.S., Sweeney, S.J., Slootmaker, C., Grear, D.A., Di Salvo, P.A., Kiser, D.,
Shwiff, S.A., 2017. Cross-species transmission potential between wild pigs, livestock,
poultry, wildlife, and humans: implications for disease risk management in North
America. Sci. Rep. 7 (1), 7821.
Pimentel, D., Zuniga, R., Morrison, D., 2005. Update on the environmental and economic
costs associated with alien-invasive species in the United States. Ecol. Econ. 52 (3),
273–288.
Seward, N.W., VerCauteren, K.C., Witmer, G.W., Engeman, R.M., 2004. Feral swine
impacts on agriculture and the environment. Sheep Goat Res. J. 12.
Tzilkowski, W.M., Brittingham, M.C., Lovallo, M.J., 2002. Wildlife damage to corn in
Pennsylvania: Farmer and on-the-ground estimates. J. Wildl. Manag. 66 (3),
678–682.
United States Department of Agriculture, 2014. 2012 Census of Agriculture, Summary
and State Data, vol. 1. Geographic Area Series, Part 51.
Wywialowski, A.P., 1994. Agricultural producers’ perceptions of wildlife-caused losses.
Wildl. Soc. Bull. 22 (3), 370–382.

Acknowledgement
This research was supported by the intramural research program of
the U.S. Department of Agriculture. The findings and conclusions in this
preliminary publication have not been formally disseminated by the U.S.
Department of Agriculture and should not be construed to represent any
agency determination or policy. Additionally, we would like to thanks
Charles A. Haley, Christine A. Kopral, Dan Grear, and Bruce A. Wagner
for their expert assistance and support.
Appendix A. Supplementary data
Supplementary data to this article can be found online at https://doi.
org/10.1016/j.cropro.2019.03.007.
References
Anderson, A., Slootmaker, C., Harper, E., Holderieath, J., Shwiff, S.A., 2016. Economic
estimates of feral swine damage and control in 11 US states. Crop Protect. 89, 89–94.
Arrington, D.A., Toth, L.A., Koebel, J.W., 1999. Effects of rooting by feral hogsSus scrofa
L. on the structure of a floodplain vegetation assemblage. Wetlands 19 (3), 535–544.

126