Rangeland Ecol Manage 65:292–298 | May 2012 | DOI: 10.2111/REM-D-11-00100.1

Does Cattle Grazing Affect Ant Abundance and Diversity in Temperate Grasslands?
Amanda C. Schmidt,1 Lauchlan H. Fraser,2 Cameron N. Carlyle,3 and Eleanor R.L. Bassett4
Authors are 1Research Assistant, Biological Sciences, Thompson Rivers University, Kamloops, BC V2C 5N3, Canada; 2Professor and 4MSc Student,
Natural Resource Sciences, Thompson Rivers University, Kamloops, BC V2C 5N3, Canada; and 3Doctoral Student, Botany Department, University of
British Columbia, Vancouver, BC V6T 1Z4, Canada.

Abstract
Half of the world’s land base is grazed by domesticated livestock. Because of the important functional role of ants in grasslands,
it is important to understand the effect of livestock grazing on ant abundance and diversity. The objectives of this study were to
examine the effect of cattle grazing and site productivity on the abundance, species richness, and species diversity of ants in Lac
du Bois Grasslands Provincial Park, British Columbia, Canada. We hypothesized that the measured ant variables would be
lowest in grazed areas and at low site productivity. Pitfall trapping was conducted at four sites: two at each low and high site
productivity levels. At each site an ungrazed (fenced exclosure) and grazed transect was sampled during May, July, and August
of 2008. Captured ants were preserved in ethanol and identified. Eight genuses of ants were collected: Tapinoma, Camponotus,
Formica, Lasius, Aphaenogaster, Myrmica, Solinopsis, and Temnotharox. The mean number of ants per pitfall was higher at
high site productivity sites that were grazed (15.10 6 2.96 SE) compared to high productivity sites ungrazed (3.28 6 0.47 SE);
grazing at low productivity reduced numbers of ants from 5.07 (6 0.70 SE) to 2.20 (6 0.39 SE) (F 5 21.806; P , 0.001).
Tapinoma sessile and A. occidentalis had the greatest numbers in the pitfall traps. Species richness (F 5 23.330, P , 0.001) and
diversity (F 5 11.764, P 5 0.001) followed a similar trend. Because productivity and cattle grazing affect ant diversity and
abundance, and ants impact ecosystem functioning, these factors should be considered in management of grasslands.

Resumen
La mitad de las tierras del mundo son pastoreadas por animales domésticos. Debido a la importancia práctica de las hormigas
dentro de los pastizales es importante comprender el efecto del ganado en pastoreo en la diversidad y abundancia de las
hormigas. Los objetivos de este estudio fueron examinar el efecto del pastoreo y la productividad del sitio en la abundancia, la
riqueza, y la diversidad de especies de hormigas en los pastizales de Lac du Bois en el parque Provincial, de la Columbia
Británica, en Canadá. Nuestra hipótesis fue que las variables medidas en las hormigas serı́an menores en áreas pastoreadas y en
sitios de menor productividad. Se utilizaron trampas en cuatro sitios: dos por cada sitio de alta y baja productividad. En cada
sitio, transectos en áreas sin pastoreo (excluidas) y con pastoreo fueron muestrados durante mayo, Julio y Agosto del 2008. Las
hormigas capturadas fueron conservadas en etanol e identificadas. Se recolectaron 8 géneros de hormigas: Tapinoma,
Camponotus, Formica, Lasius, Aphaenogaster, Myrmica, Solinopsis, and Temnotharox. El número medio de hormigas por
trampa fue mayor en de alta productividad y que fueron pastoreados (15.10 6 2.96 SE) comparados a los sitios de alta
productividad sin pastoreo (3.28 6 0.47 SE); mientras que en los sitios de baja productividad se redujo el número de hormigas
de 5.07 (6 0.70 SE) a 2.20 (6 0.39 SE) (F 5 21.806; P , 0.001). Las hormigas Tapinoma sessile y A. occidentalis tuvieron los
mayores números en las trampas. La riqueza de las especies (F 5 23.330, P , 0.001) y la diversidad (F 5 11.764, P 5 0.001)
siguió una tendencia similar. Debido a que la productividad y el pastoreo del ganando afectan la diversidad, la abundancia, y el
impacto de las hormigas en el funcionamiento del ecosistema, estos factores deben considerarse en el manejo de los pastizales.
Key Words:

disturbance, Formicidae, productivity, rangelands, semiarid grasslands

INTRODUCTION
Ants (Hymenoptera: Formicidae) represent 10–15% of animal
biomass in the majority of terrestrial systems and are among
the most dominant land organisms on Earth (Hölldobler and
Wilson 1990). Ants contribute to ecosystem function in their
ecological roles as pollinators (Hölldobler and Wilson 1990),
predators, and prey (Raine and Kansas 1990; Bull et al. 1995;
Torgerson and Bull 1995; Noyce et al. 1997); and have
important roles in grasslands as soil engineers (Whitford et al.
Research was funded in part by a Natural Sciences and Engineering Research Council of
Canada Discovery Grant to L. H. Fraser.
Correspondence: Lauchlan Fraser, Natural Resource Sciences, Thompson Rivers University,
Kamloops, BC V2C 5N3, Canada. Email: lfraser@tru.ca
Manuscript received 16 June 2011; manuscript accepted 15 February 2011.

292

1986), seed predators and foragers (Brown and Davidson 1977;
Brown et al. 1979; Higgins and Lindgren 2006), and scavengers
and decomposers (Hölldobler and Wilson 1990). Given the
dominance and diverse functional roles of ants in ecosystems it
is important to understand patterns in their distribution,
abundance, and diversity.
Considering that grazing by domesticated livestock occurs on
approximately half of the Earth’s land surface (Havstad 2008),
it is necessary to understand how the disturbance caused by
grazing may affect ant communities. Consensus as to the effects
of disturbance, in general, on ant communities has yet to be
reached; however, it is clear that different types of disturbance
(fire, agricultural, etc.) affect ant communities differently
(Folgarait 1998; Anderson and Majer 2004; Hoffmann
2010). Furthermore, ant functional groups for Australia and

RANGELAND ECOLOGY & MANAGEMENT 65(3) May 2012

North America have been classified in relation to disturbance
and stress (Andersen 1995, 1997). The effect of cattle grazing,
one type of disturbance in grasslands, reviewed by Folgarait
(1998), found that heavy grazing generally reduces ant density
and diversity, but some studies have been contradictory,
showing either no effect or even positive effects of grazing to
overall ant richness (Abensperg-Traun et al. 1996; Majer and
Beeston 1996; Bestelmeyer and Wiens 1996, 2001).
Energy availability is generally accepted as a factor that
limits diversity in natural systems (Hutchinson 1959; Connell
and Orias 1964; Currie 1991; Kaspari et al. 2000). Organisms
in higher trophic levels depend (either directly or indirectly) on
energy from primary producers. Because a high productivity
area can provide more energy to consumers than a low
productivity area of the same size, the high productivity area
will generally be able to support more individuals. If more
individuals are present, there is a greater chance that
individuals from rare species will also be present and diversity
will be higher as a result (Kaspari et al. 2000). When
productivity is low, energy availability can limit the abundance
of consumer taxa, and rare species, represented by few
individuals, are less likely to exist (Hutchinson 1959). By this
reasoning, constraining density also constrains diversity
(Hutchinson 1959; Connell and Orias 1964). In general, the
same positive relationship exists between productivity and ant
abundance and diversity (Kaspari et al. 2000).
This study examined the effects of productivity and cattle
grazing on the relative numbers of ants and on species richness
and species diversity of the ant community in the grasslands of
Lac du Bois Grasslands Provincial Park, British Columbia,
Canada. It was hypothesised that the relative number of ants
and the species richness and species diversity of ants would
increase with increasing productivity, and decrease with cattle
grazing. To study this, pitfall trapping was conducted in areas
differing in productivity level and grazing intensity at different
times during the growing season of 2008. Although there are
other methods available for estimating ant abundance, such as
direct and intensive sampling, pitfall trapping is recommended
for intersite comparisons (Romero and Jaffe 1989). However, it
should be noted that because some ants in a colony follow each
other’s trails (Hölldobler and Wilson 1990), the chance of
catching an ant of a given species may increase with every ant
of that species caught.

METHODS
Site Description
Ant specimens were collected from the temperate grasslands in
Lac du Bois Provincial Park and adjacent areas within the
bunchgrass grasslands 2–10 km north of Kamloops in the
southern interior of British Columbia, Canada. The region is
semiarid, with annual precipitation of 279 mm, 75.5 mm of
which is snowfall. Average annual daily temperature for the
region is 8.9uC, the warmest month is July, 21.0uC, and the
coldest is January, 24.2uC (Environment Canada 2009). We
selected two different grassland types associated with elevation,
lower grasslands (between 400 and 600 m above sea level
[a.s.l.]) and upper grasslands (between 800 and 1 000 m a.s.l.).
A productivity gradient correlates positively with elevation

65(3) May 2012

across the study area. This gradient is thought to be driven by a
decrease in transpiration rate with increasing elevation, where
rainfall is higher and temperature is cooler than at lower
elevations (van Ryswyk et al. 1966; Carlyle et al. 2011). In
2007, from May to September, a mean temperature of 19.3uC
was recorded in the lower grasslands and 15.4uC in the upper
grasslands. The mean total rainfall for the same period was
96 mm in the lower grasslands and 145 mm in the upper
grasslands (C. Carlyle, unpublished data). The lower grasslands
have high levels of bare ground and are dominated by
Pseudoroegneria spicata (Pursh) A. Love (bluebunch wheatgrass) and the shrub Artemisia tridentata Nutt. (big sagebrush),
with Poa secunda J. S. Presl (Sandberg’s bluegrass) and Vulpia
octiflora (Walter) Rydb. (six-week fescue) as other common
species. The upper grasslands are devoid of shrubs, have very
little bare ground, and are dominated by Festuca campestris L.
(rough fescue); Poa pratensis L. (Kentucky bluegrass) and
Juncus balticus Willd. (Baltic rush) are the next most common
species. Plant live and litter biomass is approximately four
times greater in upper grasslands compared to lower grasslands, and is reduced by grazing (Bassett 2009). The lower
grassland soil is a brown Chernozerm with a fine sandy loam
texture; the upper grassland soils are black Chernozerm (van
Ryswyk et al. 1966).
Grasslands in Lac du Bois Park are grazed by cattle from April
to November on a rest-and-rotation schedule at an animal unit
measurement of approximately one cow per hectare. Pastures
grazed in the spring one year have been rested the second year,
grazed in the fall the third year, and rested the fourth year on an
ongoing cycle over the past four decades. Approximately 20-yrold fenced cattle exclosures 100 3 150 m exist within the park as
reference sites to monitor changes in vegetation with the
exclusion of cattle grazing. We selected four paired grazed and
ungrazed (fenced) sites, two at lower and two at upper elevations
(Table S1, available at http://dx.doi.org/10.2111/REM-D-1100100.s1), for a total of eight experimental sites.

Pitfall Traps
In July 2007, pitfall traps were placed every 10 m on a 90-m
transect in each grazed and exclosed areas at each site for a
total of 10 traps per transect and 20 traps per site. A buffer of
at least 2 m was maintained from fence lines. Traps were dug
into the ground so that the tops were even with ground level.
Each trap was made of a funnel and small cup (50-mm
diameter, 30-mm depth) in a larger cup (9-mm diameter,
97-mm depth) (Brose 2003). Two holes were punched in the
bottom of each large cup to create a drain for overflow from
rain. Traps were covered with plywood cover boards
(30 3 30 3 4 cm) to reduce capture of Staphylidae beetles,
Orthopterans, and Dipterans, and were set by filling the small
cup with 20 ml each of propylene glycol and water (Grandchamp et al. 2005). In 2008, traps were set for 1 wk starting
May 15, July 16, and August 21 for a total of three trapping
periods. Samples were collected and stored in denatured
alcohol until they were sorted and counted.
Identification
Individuals were identified to species, but when this was not
possible they were identified to genus or species group.

293

Table 1. List of the species captured and the locations of their capture.
LG 5 lower grasslands, UG 5 upper grasslands. Ants were identified to
species when possible; if species could not be determined they were
listed under a higher taxonomic group.1

Subfamily

Genus

Species or
species group

Elevation of
occurrence

Dolichoderinae Tapinoma

sessile

Formicinae

Camponotus

vicinus

LG, UG
LG

Formica

Fusca species group
Rufa and Microgyna

LG, UG
LG, UG

species groups
Sanguinea species

UG

group
Lasius
Myrmicinae

LG, UG

Aphaenogaster

occidentalis

Myrmica

crassirugis

LG, UG

Solinopsis

fracticornis
molesta

UG
LG

rugatulus

LG

nevadensis

LG

Temnothorax

LG, UG

1

The Fusca species group included F. hewitti and F. subpolita. The Rufa and Microgyna
species groups included F. microgyna, F. obscuripes, and F. ravida. The Sanguinea species
group included F. puberula (a new record for British Columbia). Ants identified from the
Lasius genus included L. crypticus.

Nomenclature followed Naumann et al. (1999), except for
Myrmica crassirugus (Francoeur 2007) and Temnothorax
(Mackay 2000). All species identifications were confirmed by
Dr. Robert J. Higgins. The ant species and number of
individuals per species were recorded for each pitfall trap.

Analysis
Four pitfall traps were either removed or destroyed by animals
and were excluded from analysis. Ant species diversity was
calculated with the use of the Hill diversity number (Ludwig and
Reynolds 1988). Three two-way analyses of variance (ANOVAs)
and post hoc Tukey tests were done to test the effects of elevation
(lower and upper), and grazing (grazed, ungrazed) on the total
number of ants captured, abundance of, species richness, and
species diversity of ants. We also conducted two two-way
ANOVAs and post hoc Tukey tests to test the effects of elevation
and grazing on the number of Tapinoma sessile Say and
Aphaenogaster occidentalis Emery because these two species
were the most abundant. The factorial analyses were done with
the use of Systat 13 (Systat 2009). Nonmetric multidimensional
scaling (NMDS) was done with the use of the vegan package
(Oksanen et al. 2010) in R (R Development Core Team 2008) to
examine ant community composition. From random starting
configurations a two-dimensional solution was sought with the
use of a Bray-Curtis distance measure.

Temnothorax rugatulus Emery, and Temnothorax nevadensis
W. M. Wheeler were captured only in the lower grasslands;
Myrmica fracticornis Forel and ants in the Formica sanguinea
species group occurred only in the upper grasslands. Formica
puberula Emery was a new record for British Columbia,
Canada. Tapinoma sessile Say and Aphaenogaster occidentalis
Emery were the most common species of ants captured in this
study. Taken together these species represent 61.7% of all ants
captured (T. sessile 5 48.6%, A. occidentalis 5 13.1%).

Elevation Effects
The total number of ants captured was highest in upperelevation grasslands (Fig. 1a, Table 2), and so too was the
number of ants captured of T. sessile (6.21 [6 1.40 SE] in upper
elevation compared to 0.14 [6 0.07 SE] in lower) and A.
occidentalis (1.60 [6 0.28 SE] in upper elevation compared to
0.12 [6 0.06 SE] in lower). The mean species richness of ants
was greater in upper-elevation grasslands (Fig. 1b; Table 2).
Species diversity of ants did not differ between lower and upper
grasslands (Fig. 1c; Table 2).
Grazing Effects
Grazing increased the total number of ants captured (Fig. 1a,
Table 2), as well as increasing T. sessile (F 5 10.584;
P 5 0.001) and A. occidentalis (F 5 3.75; P 5 0.05). There
was no difference in species richness or diversity of ants
between grazed and ungrazed areas (Table 2).
Interacting Elevation and Grazing Effects
Elevation and grazing had interacting effects on total numbers of
ants captured, species richness, and diversity (Table 2). Upperelevation grazed sites had the highest total numbers of ants (as
well as T. sessile and A. occidentalis); however, at lower elevation,
ants were more numerous in exclosed areas than grazed areas
(Fig. 1a). At lower elevation, species richness was higher in
exclosures, but grazing had the opposite effect at upper elevation
(Fig. 1b). Grazed lower-elevation sites had a lower species
richness than grazed upper-elevation sites (Fig. 1b). Species
diversity was higher in lower-elevation exclosure sites compared
to lower-elevation grazed sites, but lower in upper-elevation
exclosure sites compares to upper-elevation grazed sites (Fig. 1c).
Nonmetric Multidimensional Scaling (NMDS)
The NMDS found two convergent solutions after 14 tries and had
a stress of 13.2 in two dimensions, the nonmetric fit between the
observed dissimilarity and ordination distance was R2 5 0.982. A
three-dimensional solution had a lower stress, but we chose the
two-dimensional solution because the stress value was acceptable
(McCune and Grace 2002) and two dimensions was sufficient to
express the variation within factors. The data separated out along
the x axis by elevation, with species and sites that occurred at
lower elevation on the left and the species and sites that occurred
at upper elevation on the right (Fig. 2).

RESULTS
Species Identified
Ant species from eight genera were identified from the pitfall
traps (Table 1). Most species were captured at both elevations;
however, Camponotus vicinus Mayr, Solenopsis molesta Say,

294

DISCUSSION
In all four measured response variables (total ant abundance, T.
sessile abundance, species richness, and Hill diversity) we found

Rangeland Ecology & Management

interaction effects, our results only show partial support for our
two hypotheses.
Although pitfall traps are the most commonly used method
for trapping ants in grasslands and sample surface-active ants
effectively (Romero and Jaffe 1989; Hoffman 2010) they may
be less effective for sampling ants that are active predominantly
underground or on vegetation. Also, as previously stated,
because some ants in a colony follow each other’s trails
(Hölldobler and Wilson 1990), the chance of catching an ant of
a given species may increase with every ant of that species
caught. Nevertheless, Romero and Jaffe (1989) recommend
pitfall trapping for comparison between sites.
The total number of ants captured was generally greater in
upper-elevation grasslands, as hypothesized; however, exclosures in upper grasslands had similar ant numbers as lowerelevation sites (both grazed and not grazed). Because elevation
is a strong driver of site productivity in Lac du Bois Provincial
Park (van Rieswick et al. 1966; Carlyle et al. 2011) we can
interpret our findings with regards to differences in productivity. The NMS showed separation of ant species and study
transects along the x axis according to elevation. These results
support the hypothesis that the number of ants in grasslands is
limited by energy availability. Increased primary productivity
could directly affect ant numbers because of an increase in
available resources. An area with more resources can likely
support greater numbers of individual ants. The results from
this study are consistent with those found in a study done by
Kaspari et al. (2000) that also evaluated the number of ants
over a productivity gradient. Considering structural complexity
may be useful in explaining these results. Generally, habitats
with higher structural complexity support greater biodiversity
because they provide more ecological niches; as such, the
habitat requirements of more species can be met (Currie 1991).
Bestelmeyer and Wiens (2001) found a relatively high ant
richness and diversity in some Atriplex canescens shrub land,
compared to short-grass steppe. In this study, lower elevation
sites have grasses, bare ground and sage brush but high
elevation sites have mostly rough fescue and other types of
grass. It is possible that upper elevation, high productivity sites
causes an increase in the abundance of only a few dominant
species of ants, and that the lower levels of structural
complexity is responsible for the decreased richness and
diversity of ants captured there. In this case, the dominant
ant species (T. sessile and A. occidentalis) did have higher
relative abundances in high productivity grasslands which
provide some support for this idea. Additionally, the observation that C. vicinus occurred only in lower-elevation grasslands
where the woody substrate they prefer for nesting is more
available further supports this idea.
Figure 1. Mean (+/2SE) relative total ant numbers captured (a),
species richness (b), and species diversity (Hill diversity number N1) (c).
Error bars indicate standard error. The letters above the error bars
indicate significant differences among bars based on a post hoc Tukey
test (P , 0.05).

interacting effects between elevation and grazing. We found
that the number of ants captured increased in grazed sites at
upper elevation (i.e., high productivity). However, ant numbers
was reduced by grazing in lower-elevation sites. Because of the

65(3) May 2012

Grazing Response
The prediction that ants would be more abundant in ungrazed
areas than in grazed areas was not supported; as a main effect,
there was no difference in the relative abundance of ants
between grazed and exclosed areas. Similarly, the species
richness and species diversity of ants was not different between
grazed and ungrazed areas. Predictions that the species richness
and diversity of ants would be lower in grazed sites were
originally based on the observation that generally heavy

295

Table 2. Separate and interacting effects of elevation (lower and upper) and grazing (grazed and exclosures) on ant total number of ants captured,
species richness, and Hill diversity. Bold numbers indicate significance at the P , 0.05 level.
Total number of ants captured

Elevation

Species richness

Hill diversity (N1)

F

P

F

P

F

P

12.484

, 0.001

4.171

0.042

0.077

0.781

Grazing

8.100

0.005

0.216

0.642

0.009

0.926

Elevation 3 grazing

21.806

, 0.001

23.330

, 0.001

11.764

0.001

grazing reduces ant density and diversity (Folgarait 1998;
Hoffman 2010), but in this study the sites were moderately
grazed, not heavily grazed. Still, the relative abundance of T.
sessile was greater in grazed areas than exclosed areas. This
indicates that grazing does effect the abundance of some species
of ants and that grazing effects can act to increase ant numbers
in some cases.

Interacting Elevation and Grazing Responses
Grazing and elevation (productivity) had significant interacting
effects on the relative numbers of ants captured and species
richness of ants. Areas with high productivity and grazing had a

Figure 2. Multidimensional scaling ordination plot showing locations of
transects and ant taxa. The ellipses (95% confidence interval) indicate
separation of the low- and high-elevation locations along NMDS 1, with
the left representing low productivity grasslands and the right
representing high productivity grasslands. Symbols are as follows:
black 5 grazed, gray 5 ungrazed; triangle 5 May, square 5 July, circle 5 August; solid 5 high productivity, open 5 low productivity. The
Fusca species group referred to as ‘‘F. fusca’’ included F. hewitti and
F. subpolita. The Rufa and Microgyna species groups referred to as
‘‘F. spp.’’ included F. microgyna, F. obscuripes, and F. ravida. The
Sanguinea species group referred to as ‘‘F. Sanguinea’’ included
F. puberula (a new record for British Columbia). Ants identified from
the Lasius genus referred to as ‘‘Lasius’’ included L. crypticus.

296

much higher number of ants than all other areas; however, of
low productivity sites, exclosed areas had a higher relative
number of ants than grazed areas. Structural complexity and
resource availability were likely driving these patterns. The
plant modification that takes place with grazing could be of
varying importance depending on productivity of the site,
because both the quantity and the type of vegetation changes at
different elevations. These differences may be affecting both
competitors and predators of ants. In a study on seed-eating
rodents and ants, it was found that changes in the population of
each were reciprocal as a result of competition for resources
(Brown et al. 1979). It is possible that seed-eating rodents and
other granivores such as birds find the high productivity,
ungrazed grasslands in this study to be a more suitable habitat
than the high productivity, grazed grasslands because ungrazed
vegetation provides better cover from predators (Carlyle et al.
2010). The higher competition in ungrazed areas at high
productivity would likely reduce ant abundance there. In a
similar way, the ungrazed high productivity grasslands may
provide a better habitat for predators of ants such as spiders
and birds, which would also act to reduce ant abundance. At
low productivity, a different pattern is seen, as exclosed areas
had a higher relative abundance than grazed areas. The high
abundance of big sagebrush at lower sites could be providing
the cover and habitat needed for predators and competitor
species to ants, allowing resource availability to be the
prevailing driving factor at those sites. Species richness of ants
was also affected by the interacting effects of productivity and
grazing. The highest species richness occurred in exclosed
ungrazed sites, and the trend for species diversity was similar
but was not significant. This is likely due to higher structural
complexity owing to the presence of big sagebrush and lack of
grazing.

Species Descriptions
Two species, T. sessile and A. occidentalis, represented more
than 60% of all ants captured. Tapinoma sessile was the only
species caught from the subfamily Dolichoderinae during this
study, and was captured at both low and high productivity
sites. This species can be lestobiotic (meaning that it nests in the
walls of other species’ nests, steals food and resources from the
host nest, and preys upon host workers and brood), but can
also be independent, forming nests in soil or under rocks,
wood, or dung. This small ant typically has colonies with
thousands of individuals and feeds on fruit juices, nectars, flesh
of other organisms and sometimes tends aphids or other
honeydew secretors (Smith 1928; Naumann et al. 1999; Heron
2005). Aphaenogaster occidentalis is a species that nests in
both extremely covered and open areas and usually has
hundreds of individuals in each colony (Naumann et al.

Rangeland Ecology & Management

1999; Heron 2005). This slow-moving ant was captured at
both low and high productivity sites and was relatively
numerous in this study, as well as in a grassland study done
by Heron (2005).

MANAGEMENT IMPLICATIONS
Ants perform many different ecosystem functions and therefore
have extensive impacts on their environment. Although
grassland management is typically concerned with vegetation
and mammals, consideration of invertebrates such as ants is
important for maintaining biodiversity and ecosystem function.
The results of this study are useful for informing grazing and
biodiversity management of grasslands. This study suggests
that when designing grazing regimes ant diversity could be
maximized to contribute to overall biodiversity by maintaining
and adding to exclosed areas, or reducing grazing intensity, at
low productivity levels. This would be most important early in
the growing season; avoiding grazing in low productivity areas
altogether until later in the season when impacts on species
richness would be less severe would also help to increase
biodiversity.

ACKNOWLEDGMENTS
We thank Jessica Gossling and Anna-Maria Pellet for help collecting pitfalls
in the field. Dr. Rob Higgins verified identification of ant taxa. We thank
Agriculture and Agri-Foods Canada, Kamloops Range Research branch for
allowing use of cattle exclosures and the British Columbia Ministry of
Environment for allowing access to Lac du Bois Provincial Park. This work
was funded by a Natural Sciences and Engineering Research Council
(NSERC) Discovery Grant to L.H.F.

LITERATURE CITED
ABENSPERG-TRAUN, M., G. T. SMITH, G. W. ARNOLD, AND D. E. STEVEN. 1996. The effects
of habitat fragmentation and livestock grazing on animal communities in
remnants of gimlet Eucalyptus salubris woodland in the Western Australian
wheatbelt. I. Artropids. Journal of Applied Ecology 33:1281–1301.
ANDERSEN, A. N. 1995. A classification of Australian ant communities, based on
functional groups which parallel plant life-forms in relation to stress and
disturbance. Journal of Biogeography 22:15–29.
ANDERSEN, A. N. 1997. Functional groups and patterns of organization in North
American ant communities: a comparison with Australia. Journal of
Biogeography 24:433–460.
ANDERSEN, A. N., AND J. D. MAJER. 2004. Ants show the way down under:
invertebrates as bioindicators in land management. Frontiers in Ecology and
the Environment 2:291–298.
BASSETT, E. R. L. 2009. The effects of grazing and site productivity on carabid
beetles (Coleoptera: Carabidae) in a semi-arid grassland [master of science
thesis]. Kamloops, British Columbia, Canada: Thompson Rivers University.
BATES, J. D., R. F. MILLER, AND T. J. SVEJCAR. 2000. Understory dynamics in cut
and uncut western juniper woodlands. Journal of Range Management
53:119–126.
BESTELMEYER, B. T., AND J. A. WIENS. 1996. The effects of land use on the structure
of ground-foraging ant communities in the Argentine Chaco. Ecological
Applications 6:1225–1240.
BESTELMEYER, B. T., AND J. A. WIENS. 2001. Ant biodiversity in semiarid landscape
mosaics: the consequences of grazing vs. natural heterogeneity. Ecological
Applications 11:1123–1140.

65(3) May 2012

BROSE, U. 2003. Bottom-up control of Carabid beetle communities in early
successional wetlands: mediated by vegetation structure or plant diversity?
Oecologia 135:407–413.
BROWN, J. H., AND D. W. DAVIDSON. 1977. Competition between seed-eating rodents
and ants in desert ecosystems. Science 196:880–882.
BROWN, J. H., D. W. DAVIDSON, AND O. J. REICHMAN. 1979. An experimental study of
competition between seed-eating desert rodents and ants. American Journal
of Zoology 19:1129–1143.
BULL, E. L., T. R. TORGERSON, A. K. BLUMTON, C. M. MCKENZIE, AND D. S. WYLAND. 1995.
Treatment of an old-growth stand and its effects on birds, ants, and large
woody debris: a case study. Portland, OR, USA: USDA Forest Service Pacific
Northwest Research Station. Gen. Tech. Rep. PNW-GTR-353. 12 p.
CARLYLE, C. N., L. H. FRASER, C. M. HADDOW, B. A. BINGS, AND W. HARROWER. 2010. The
use of digital photos to assess visual cover for wildlife in rangelands. Journal
of Environmental Management 91:1366–1370.
CARLYLE, C. N., L. H. FRASER, AND R. TURKINGTON. 2011. Tracking soil temperature and
moisture in a multi-factor climate experiment in temperate grassland: do climate
manipulation methods produce their intended effects? Ecosystems 14:489–502.
CONNELL, J., AND E. ORIAS. 1964. The ecological regulation of species diversity.
American Naturalist 98:399–414.
CURRIE, D. J. 1991. Energy and large-scale patterns of animal- and plant-species
richness. American Naturalist 137:27–49.
ENVIRONMENT CANADA. 2009. National Climate Data and Information archive. Available at:
http://climate.weatheroffice.ec.gc.ca/climate_normals/index_e.html. Accessed 6 October 2009.
FOLGARAIT, P. J. 1998. Ant biodiversity and its relationship to ecosystem
functioning: a review. Biodiversity and Conservation 7:1221–1244.
FRANCOEUR, A. 2007. The Myrmica punctiventris and M. crassirugis species groups
in the Nearctic region. Memoirs of the American Entomological Institute
80:153–185.
GRANDCHAMP, A. C., A. BERGAMINI, S. STOFER, J. NIEMELA, P. DUELLI, AND C. SCHEIDEGGER.
2005. The influence of grassland management on ground beetles (Carabidae,
Coleoptera) in Swiss montane meadows. Agriculture, Ecosystems and
Environment 110:307–317.
HAVSTAD, K. M. 2008. Mongolia’s rangelands: is livestock production the key to the
future? Frontiers in Ecology and the Environment 6:385–391.
HERON, J. 2005. Ants of the south Okanagan grasslands, British Columbia.
Arthropods of Canadian Grasslands 11:17–22.
HIGGINS, R. J., AND B. S. LINDGREN. 2006. The fine scale physical attributes of coarse
woody debris and effects of surrounding stand structure on its utilization by
ants (Hymenoptera: Formicidae) in British Columbia. In: Insect biodiversity and
dead wood: Proceedings of a symposium for the 22nd International Congress
of Entomology. Asheville, NC, USA: USDA Forest Service Southern Research
Station. Gen. Tech. Rep. SRS-93. p. 67–74.
HOFFMANN, D. B. 2010. Using ants for rangeland monitoring: global patterns in
the responses of ant communities to grazing. Ecological Indicators 10:
105–111.
HÖLLDOBLER, B., AND E. O. WILSON. 1990. The ants. Cambridge, MA, USA: The
Belknap Press of Harvard University Press.
HUTCHINSON, G. E. 1959. Homage to Santa Rosalia, or why are there so many kinds
of animals? American Naturalist 93:145–159.
KASPARI, M., S. O’DONNELL, AND J. R. KERCHER. 2000. Energy, density, and constraints
to species richness: ant assemblages along a productivity gradient. American
Naturalist 155:280–293.
LUDWIG, J. A., AND REYNOLDS, J. F. 1988. Statistical Ecology: A Primer on Methods
and Computing. New York, NY, USA: John Wiley & Sons.
MACKAY, W. P. 2000. A review of the New World ants of the subgenus Myrafant,
(genus Leprothorax) (Hymenoptera: Formicidae). Sociobiology 36:265–444.
MAJER, J. D., AND G. BEESTON. 1996. Biodiversity integrity index: an illustration using
ants in Western Australia. Conservation Biology 10:65–74.
MCCUNE, B., AND J. B. GRACE. Analysis
.
of ecological communities. Gleneden Beach,
OR, USA: MjM Software Design.
NAUMANN, K., W. B. PRESTON, AND G. L. AYRE. 1999. An annotated checklist of the
ants (Hymenoptera: Formicidae) of British Columbia. Journal of the
Entomological Society of British Columbia 96:29–68.

297

NOYCE, K. V., P. B. KANNOWSKI, AND M. R. RIGGS. 1997. Black bears as anteaters:
seasonal associations between bear myrmicophagy and ant ecology in north
central Minnesota. Canadian Journal of Zoology 75:1671–1686.
OKSANEN, J., F. G. BLANCHET, P. KINDT, P. LEGENDRE, R. B. O’HARA, G. L. SIMPSON,
P. SOLYMOS, M. H. H. STEVENS, AND H. WAGNER. 2010. vegan: Community Ecology
Package. R package version 1.17-3.
R DEVELOPMENT CORE TEAM. 2008. R: a language and environment for statistical
computing. Vienna, Austria: R Foundation for Statistical Computing. Available
at: http://www.R-project.org.
RAINE, R. M., AND J. L. KANSAS. 1990. Black bear seasonal food habits and distribution by
elevation in Banff national park, Alberta. In: L. M. Darling and W. R. Archibald [EDS.].
Proceeding for the Eighth International Conference of Bear Research and
Management. Victoria, BC, Canada: International Association for Bear Research
and Management. p. 297–304.

298

ROMERO, H., AND K. JAFFE. 1989. A comparison of methods for sampling ants
(Hymenoptera, Formicidae) in savannas. Biotropica 21:348–352.
SMITH, M. R. 1928. The biology of Tapinoma sessile Say, an important-house
infesting ant. Annals of the Entomological Society of America 21:307–330.
SYSTAT SOFTWARE, INC. 2009. SYSTAT 13 Statistics. Chicago, IL, USA: SYSTAT
Software, Inc.
TORGERSON, T. R., AND E. V. BULL. 1995. Down logs as habitat for forest dwelling
ants—the primary prey of pileated woodpeckers in northeastern Oregon.
Northwest Science 69:294–303.
VAN RYSWYK, A. L., A. MCLEAN, AND L. S. MARCHAND. 1966. The climate, native
vegetation, and soils of some grasslands at different elevations in British
Columbia. Canadian Journal of Plant Science 46:35–50.
WHITFORD, W. G., D. SCHAEFER, AND W. WISDOM. 1986. Soil movement by desert ants.
Southwest Naturalist 31:273–274.

Rangeland Ecology & Management