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Presence and Abundance of Birds in an Atlantic Forest Reserve and Adjacent Plantation of Shade-Grown Yerba Mate, in Paraguay


Abstract and Figures

In the Atlantic forest region, there is a need to develop economic activities that can be carried out in buffer zones around parks, with minimal impact on forest bird species. One such possibility is the farming of yerba mate, Ilex paraguariensis, under native trees. We compared bird speciesȁ9 presence and abundance between a forest reserve and an adjacent plantation of shade-grown yerba mate, to determine which species might use such plantations. Of the 145 species that were regularly recorded in the forest, 66%, including five globally threatened species, were also regularly recorded in the plantation. Most canopy species and tree trunk insectivores showed similar abundance in both habitats, but forest floor and understory species were absent from the plantation. Within the plantation, higher tree density did not lead to a greater abundance of forest birds. Yerba mate grown under native trees could be used to rehabilitate cleared land and allow recolonization by some Atlantic forest bird species.
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Presence and abundance of birds in an Atlantic forest
reserve and adjacent plantation of shade-grown yerba
mate, in Paraguay
Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4J1;
Paraguay, Comandante Rafael Franco 381 c/ Leandro Prieto, Asuncio
n, Paraguay;
Address: Fundacio
n de Historia Natural Fe
lix de Azara, Pero
n 2933, Buenos Aires, Argentina, 1198;
*Author for correspondence (e-mail:; phone/fax: +54-11-4766-5833)
Received 6 November 2003; accepted in revised form 18 May 2004
Key words: Agriculture, Agroecosystem, Atlantic forest, Birds, Ilex paraguariensis, Shade-grown,
Yerba mate
Abstract. In the Atlantic forest region, there is a need to develop economic activities that can be
carried out in buffer zones around parks, with minimal impact on forest bird species. One such
possibility is the farming of yerba mate, Ilex paraguariensis, under native trees. We compared bird
species’ presence and abundance between a forest reserve and an adjacent plantation of shade-
grown yerba mate, to determine which species might use such plantations. Of the 145 species that
were regularly recorded in the forest, 66%, including five globally threatened species, were also
regularly recorded in the plantation. Most canopy species and tree trunk insectivores showed
similar abundance in both habitats, but forest floor and understory species were absent from the
plantation. Within the plantation, higher tree density did not lead to a greater abundance of forest
birds. Yerba mate grown under native trees could be used to rehabilitate cleared land and allow
recolonization by some Atlantic forest bird species.
The Atlantic forest of southeas tern Brazil, northeastern Argentina, and
eastern Paraguay, is one of the world’s top five biodiversity hotspots (Myers
et al. 2000) and one of South America’s highest priorities for bird conser-
vation (Stotz et al. 1996; Stattersfield et al. 1998). Agriculture, cattle-ranch-
ing, and industry have replaced more than 90% of the Atlantic forest, mostly
within the last 30 years. The diverse bird community is threatened by high-
grade logging (Aleix o 1999), hunting (BirdLife International 2000), habitat
loss, and habitat fragmentation (Marsden et al. 2001), all of which have led
to local extirpations of formerly common species (Willis 1979; Christiansen
and Pitter 1996; Ribon et al. 2003). In total, 61 of the Atlantic forest’s 199
endemic bird species are endangered, vulnerable, or extinct in the wild
(IUCN 2002; endemism from Stotz et al. 1996). Indeed , this region now
contains more critically endangered birds than any other in the neotropics
(Stotz et al. 1996).
Biodiversity and Conservation (2005) 14:3265–3288 Springer 2005
DOI 10.1007/s10531-004-0446-0
Protected areas should be the top priority for conservin g Atlantic forest birds,
but, given the region’s large population, private land-ownership , and rapid
deforestation, it is also important to find economically viable activities that do
not involve total deforestation. For example, existing parks require buffer zones
in which economic activities are limited, and, preferably, compatible with
conservation. One such activity could be the production of shade-tolerant crops
under a tree canopy. Research in Africa, Asia, an d Latin America suggests that
such shade-grown crops can conserve some species of birds and other wildlife,
especially when planted under a diverse canopy of native trees and located near
native forest (Moguel and Toledo 1999; Rice and Greenberg 2000).
One of the Atlantic forest region’s most widespread crops is the native yerba
mate, Ilex paraguariensis, whose leaves are used to make mate (hot tea) and
terere (cold tea). Although it is almost always produced as a monoculture in
full sun, yerba mate can be grown in shade under native trees (Eibl et al. 2000).
For certified organic, shade-grown yerba, farmers in Paraguay receive three
times the price of traditional, sun-grown yerba, making shade-grown yerba an
economically viable option despite slightly lower yields (A. Pryor in litt.). Thus,
shade-grown yerba mate could be planted in buffer zones or biosphere reser ves
as a compromise between bird conservation and agriculture.
Despite the potential for yerba mate to be grown under native trees, it is not
clear how such plantations would be used by birds in the region. If shade-
grown crops are to be used in buffer zones, it is important to identify which
forest birds occur in such plantations, and how plantations may be managed to
promote bird conservation.
To our knowledge, only one study has examined the potential for shade-
grown crops to conserve Atlantic forest birds. In Brazil’s coastal Atlantic
forest, Alves (1990) found that, with the exception of tinamous (Tinamidae),
cracids (Cracidae), antbirds (Formicariidae), and manakins (Pipridae), most
bird families present in the forest were also represented in shade-grown cacao
Here we confirm and extend Alves’ (1990) findings in a species-level study of
birds in an Atlantic forest reserve and adjacent plantation of shade-g rown
yerba mate. Our fir st objective was to compare the presence and abundance of
bird species in the forest reserve and adjacent plantation, and to compare
differences in presence and abundance between broad groups of birds char-
acterized by typical habitat, strata, and diet. Our second objective was to
compare two parts of the plantation that differed in tree density and canopy
cover, to determine wheth er higher tree density in the plantation led to higher
total abundance of birds in any of the ecological groups.
Our study was conducted between 16 October and 5 December 2001 (austral
spring) and 19 February and 22 April 2002 (late summer, early autumn) at
Estancia Itabo
, Department of Canindeyu´ , Paraguay (2430¢S5438¢W,
elevation 300 m).
Study site
The study site was located within a 5000 ha tract of Atlantic forest and an
adjacent 80 ha plantation of shade-grown yerba mate, and included approxi-
mately 50 ha of the forest and 45 ha of the planta tion (Figure 1). Fifty hectare
plots are considered necessary to avoid missing rare species in diverse tropical
forest bird communities (Terborgh et al. 1990). The size and layout of the
plantation did not allow for replication of such large plots, and trails were too
close together to be independent; thus, we compare the bird community
between the entire 50 ha of forest and the entire 45 ha of plantation.
Figure 1. A map of the study site showing the forest, the plantation, the trails surveyed in spring
and autumn, and features of the surrounding landscape. Pale gray is degraded forest and capuera
(cleared areas that are now regenerating).
Overall, the forest and plantation were similar in terms of elevation, slope,
tree species, density of standing-dead trees, and abundance of epiphytes
(Cockle 2003). Both had been subject to light logging 25 years before our
study. The plantation was created by removing the forest understory and some
trees, then planting yerba mate below the tree canopy. Thus, the forest had
more lianas and vines, and greater canopy cover than the plantation (80%
canopy cover in the forest compa red to 60% in the plantation; see Cockle 2003
for more details on the study site).
Within the plantation, we also compared a 12 ha subplot with high tree
density and canopy cover (343 stems/ha; 80% cover), to a 12 ha subplot with
low tree density and canopy cover (137 stems/ha; 50% cover; Figure 1).
In the forest, we surveyed birds along three trails (525, 1260, and 1000 m, for
a total length of 2785 m) that were separated by at least 300 m at all points,
and began 75 m from the plantation. In the plantation, we surveyed birds
along trails that formed a grid of 200 m · 200 m cells. We surveyed 15 cells in
the spring sampling period and nine in the autumn. Routes in both habitats
were marked every 25 m with numbered tags that served as reference points for
recording bird locations.
Sampling techniques
Where possible, we used spot-mapping to census birds (International Bird
Census Committee 1969; Bibby et al. 2000). We surveyed the forest and
plantation on alternate days, choosing our routes in advance and using dif-
ferent starting points and directions to balance for time-of-day within and
between sites. In total, we surveyed the entire study site six times in each of
spring an d autumn. Birds were never surveyed during rain.
Beginning 30 min before first light and for the next 3–4.5 h, we spot-
mapped birds along 1–3 km of trail per day, noting every individual or group
of birds heard or seen. We identified each bird to species based on songs, calls,
and/or visual observation, then estimated its distance and measured its
compass direction from our location. We periodically checked distance esti-
mates by visually confirming the location of a bird that had been detected
aurally. We could reliably estimate distance and direction for all but two
species (Chamaeza campanisona and Grallaria varia), which we did not
attempt to spot-map.
Where possible, we recorded sex, age (adult, immature, or dependent
fledgling), behavior (singing, feeding, carrying food, carrying nesting material,
begging, fighting, etc.), and whether two records of the same species were
simultaneous. Mixed species flocks were treated as a single record, but the
number and species of birds in the flock were recorded. For single-species
groups registered aurally, we noted simply ‘group’ and later substituted the
average group size for that species based on visual observations. We later
omitted birds flying in a straight line over the study site and all birds recorded
outside the plot that we were surveying (e.g. birds calling in the forest while we
were surveying the plantation).
Nocturnal species were spot-mapped in the pre-dawn period of the
morning surveys, and in surveys on five clear moonlit nights (between dusk
and 02:00). On a further 16 nights we played back recordings of 13 nocturnal
species (for details see Cockle 2003); howeve r, we failed to detect any new
species using playback, so the results of these surveys are omitted here.
Playback was most useful in establishing the year-rou nd presence and terri-
toriality of Strix huhula and Strix virgata at our study site (for details see
Cockle 2003).
A preliminary analysis showed that, with the exception of a few migratory
species, there was little variation between seasons in the presence and abun-
dance of birds, so we pooled data over the two seasons. Based on published
literature (e.g. Sick 1993; Stotz et al. 1996) and AB’s field experience, we placed
each species into one of the following three categories (see Appendix 1): (1)
forest species, (2) edge species (includes species associated with anthropogenic
habitats), and (3) aerial species (those that spend most of their active time in
the air). Forest species were then divided into five groups based on the strata in
which they are most often found: (1) canopy species, (2) midstory species, (3)
understory spec ies, (4) forest floor species, and (5) tree trunk species, and five
groups based on the predominant food items in their diet: (1) fruit-or-grain-
eaters, (2) fruit-and-insect-eaters, (3) insectivores, (4) nectarivores, (5) carni-
vores and carrion-eaters.
Qualitative measures
Species were considered to be occasional or accidental, and therefore excluded
from the qualitative analysis, if they were encountered on few er than five
occasions and either (a) used the site only as a stop-over during migration (e.g.
Elaenia albiceps), (b) were found only within 20 m of the edge of the habitat
(e.g. Thamnophilus caerulescens in the plantation), or (c) were visiting from
outside the study site (e.g. Syndactila rufosuperciliata visiting from nearby
gallery forest).
We tested the completeness of species lists by plotting species accumulation
curves for the forest and the plantation. Since species richness is affected by
plot size (James and Rathbun 1981), we calculated species richness using only
the part of the plantation that was surveyed in both seasons (43.8 ha) and an
equivalent sized, randomly selected portion of the forest (also 43.8 ha), here-
after referred to as the ‘main plots’. We assumed that most species at our study
site could be detected up to 100 m away. In order to reduce differences in
detectability between habitats, and to be certain that all our records fell within
the habitat we were surveying, we excluded birds detected beyond 100 m from
our location. We plotted the accumulated number of species against the total
number of individuals accumulated in each of the two main plots. Since both
curves reached a plateau, species richness is compared based on the total
number of species accumulated in each of the main plots.
We calculated the Sørensen coefficient (Brower and Zar 1977) to examine
qualitative community similarity between the forest and the plantation, based
on the species found in the main plots:
¼ 2c=ð s
þ s
where s
is the number of species in community 1 (forest), s
is the number of
species in community 2 (plantation) an d c is the number of specie s shared by
both communities.
For each habitat-, strata- and diet group, we calculated the number of
species found only in the forest (forest-restricted), as a proportion of all species
in the group. For example, a high proportion of forest-restricted species in a
given diet group suggests that birds dependent on the given food source
avoided the plantation. We tested wheth er different habitat-, strata-, and diet
groups had different proportions of forest-restricted species, using a v
of contingency tables with v
= 0.05 (Zar 1999).
Quantitative measures
Since we spent about equal time in each habitat (104 and 103 morning hours in
the forest and plantation, respectivel y), we compared the total num ber of
encounters (records) of each species between habitats, for each of the 123
species that was recorded more than 10 times, to get an index of abundance.
Because we covered the same routes every week, our records presumably in-
cluded repeat observations of the same individuals, thus violating the inde-
pendence assumptions of most statistical tests. Rather than test for statistical
differences between the forest and plantation, we considered a species to be
more abundant in the forest than in the plantation if there were at least twice as
many records of that species in the forest as in the plantation. To find out
whether habitat-, strata-, and diet groups differed in the proportion of species
that were more abundant in the forest than in the plantation, we used a v
analysis of contingency tables with v
= 0.05 (Zar 1999).
For 31 territorial species, we also estimated breeding density using stan-
dard territory mapp ing (International Bird Census Committee 1969) with
some modifications to adapt the method to the tropics (after Terborgh et al.
1990; Thiollay 1994; see Cockle 2003, for details). To calculate breeding
density, we divided the number of territories by the area surveyed, and
multiplied by 100 for a density expressed as N territories/100 ha. Since trails
were at least 200 m apart, we did not assume to have surveye d all points
between trails. Rather, we plotted a detection function (number of encounters
versus distance from trail) for each species, and used the shoulder of this
curve to determine the area that was effectively mapped (see Cockle 2003, for
details). We considered species to differ in density between the two habitats if
their density was twice as high in one habitat as in the other (following
Marsden et al. 2001).
Comparisons within the plantation
To determine whether variation in tree density affected the use of the planta-
tion by birds, we compared two 12 ha subplots within the plantation. For
comparison, we selected a subset of the total visits to the subplots, balancing
for time of day, time of year, and location within the subplot (i.e. corner, edge,
or middle). Night birds were excluded. This exercise reduced our sample size,
so that we did not have enough observations to detect all species in each of the
two subplots, or to compare the number of encounters by species. Instead, we
compared the two subplots based on the total number of encounters of birds in
each habitat-, strata-, and diet group (adding up all the records of all species in
each group).
In 207 h of morning spot-mapping and 29 h of night-surveys and playback, we
registered 13,752 contacts with 201 species of birds in the study site.
Figure 2. Total number of species recorded in the main plots in the forest (solid line) and in the
plantation (broken line) in relation to the total number of records of any species in the same plot.
Species richness
In the main plots, we registered 4627 contacts in the forest and 4024 contacts in
the plantation. We detected 165 species of birds (occasional species omitted):
145 in the forest and 116 in the plantation (Figure 2).
Qualitative community similarity
In total, 49 of the 165 species recorded in the main plots were found only in the
forest, 96 were found in both habitats, and 20 were restricted to the plantation.
Thus, 66% of the birds present in the forest were also present in the plantation,
and Sørensen’ coefficient of community similarity was 0.74.
The proportion of species restricted to the forest differed significantly among
habitat groups (v
=16.7, df = 2, p < 0.001) and strata groups (v
=48.3, df
=4,p < 0.001), but not diet groups (v
=9.34, df = 4, p > 0.05; Table 1).
Forest birds, especially understory-, forest floor-, and midstory species, were
those most often restricted to the forest (Table 1).
Total numbe r of encounters for each species
Overall, 40% of species were encountered at least twice as many times in the
forest as in the plantation, and were considered to be more abundant in the
forest. We found significant differences among habitat groups (v
df= 2, p < 0.001), strata groups (v
= 39.2, df = 4, p < 0.001), and diet
Table 1. Percent (%) of species in each habitat-, strata-, and diet group, that 1) were restricted to
the forest, and 2) were more abundant in the forest than in the plantation (twice as many records in
the forest as in the plantation).
Restricted to the forest More abundant in the forest
Total 30 40
Edge species 3 0
Aerial species 0 0
Forest species 38 52
Canopy species 14 24
Midstory species 44 81
Understory species 88 100
Forest floor species 70 80
Tree trunk species 9 12
Fruit-or-grain eaters 20 17
Fruit-and-insect eaters 30 46
Insectivores 44 60
Nectarivores 0 100
Carnivores 67
groups (v
=10.6, df = 3, p < 0.025) in the proportion of species that showed
higher abundance in the forest than the plantation (Table 1).
Estimated density
Of the 31 territorial species for which we estimated density, only two were
present in similar densities in both habitats (no more than twice as many
territories in one habitat as in the other; Figure 3). Of the remaining 29 species,
20 were more than twice as common in the forest, and 9 were more than twice
as common in the plantation.
Threatened species
During this study we recorded one Endangered species (Amazona vinacea;
lUCN, 2002), one Vulnerable species (Tinamus solitarius; IUCN, 2002) and five
near-threatened species (Dryocopus galeatus, Piculus aurulentus, Phylloscartes
eximius, Phylloscartes sylviolus, and Polioptila lactea; IUCN, 2002). All seven
species were encountered in the forest, and five were also encountered in the
plantation. Amazona vinacea, Phylloscartes sylviolus,andPolioptila lactea were
recorded at least twice as often in the plantation as in the forest.
Comparisons within the plantation
In the selec ted spot-mapping visits to the high- and low tree density subplots,
we recorded 3202 contacts with 106 species of birds. Bot h forest- and edge
birds were more common in the low tree density subplot (Figure 4). Among
forest birds, canopy species and fruit-or-grain-eaters were markedly more
common in the low tree density subplot, while understory species wer e more
common in the high tree density subplot (Figure 4).
The composition of the bird community differed between the shade-grown
yerba plantation and the forest, but 66% of the species using the forest
also used the plantation. Forest birds were both more abundant and more
diverse in the forest, while edge species were more abundant and more
diverse in the plantation. Never-the-less, five IUCN-listed forest species
were encountered in the plantation (of seven recorded in the forest).
Midstory, forest floor, and understory species, in particular, were less di-
verse and less abundant in the plantation. In contrast, canopy- and tree
trunk birds showed high community similarity and similar numbers of
encounters in both habitats, suggesting that most species in these groups
are able to use the plantation habitat. We found stronger differences be-
tween strata groups than between diet groups, but, among forest birds,
fruit-or-grain-eaters were found more often in the plantation compared to
the other diet groups.
Within the plantation, both fores t- and edge species were most abundant
where tree density was low. Among forest species, canopy birds made up
the majority of the records and were most common where tree density was
low, while the few understory and midstory birds were more abundant
where tree density was high. Among forest canopy species, fruit-and-grai n-
eaters were the only diet group with a large difference in abundance be-
tween the two tree densities, with a higher abundance where tree density
was low.
There are four main sources of bias that could affect our results. (1)
The layout of survey routes differed between the plantation (grid) and the
forest (long trails), so that rare species wer e more likely to be absent from
the plantation by chance. We minimized this bias by using large plots (see
Terborgh et al. 1990). (2) We spent considerable time surveying along the
Figure 3. Number of territories per 100 ha, for 31 species, in the forest (black) and plantation
(white). 1 = Basileuterus culicivorus,2=Myiornis auricularis,3=Conopophaga lineata,
4=Synallaxis ruficapilla,5=Crypturellus obsoletus,6=Basileuterus leucoblepharus,
7=Platyrinchus mystaceus,8=Dysithamnus mentalis,9=Thamnophilus caerules-
cens,10=Hemitriccus diops,11=Trichothraupis melanops,12=Capsiempis flaveola,
13 = Otus atricapillus,14=Synallaxis cinerascens,15=Lathrotriccus euleri,16=Glaucidium
brasilianum,17=Otus choliba,18=Leptopogon amaurocephalus,19=Corythopis delalandi,
20 = Habia rubica,21=Automolus leucophthalmus, 22 = Myiodynastes maculatus,23=Mio-
nectes rufiventris,24=Contopus cinereus,25=Pitangus sulphuratus,26=Troglodytes aedon,
21 = Megarynchus pitangua,28=Colonia colonus,29=Camptostoma obsoletum,30=Myioz-
etetes similis,31=Falco sparverius.
edge of the plantation, but almost no time at the edge of the forest.
This biased our results toward a lower number of encounters in the planta-
tion compared to the forest, because we ignored birds detected outside of the
habitat we were surveying. (3) Visibility (and hence detectability) was higher
in the plantation than in the forest. (4) Our study considered only one
plantation and only one forest site, so our results cannot be generalized.
Figure 4. Number of bird records in low- (white) and high- (stippled) tree density subplots within
the plantation, for each of the habitat-, strata-, and diet groups. Nectarivores are excluded because
there were no canopy nectarivores at our study site.
Shade-grown crops as habitat for forest birds
With some exceptions, our species-level study was consistent with the results of
Alves’ (1990) study that examined families of Atlantic forest birds in a shade-
grown crop. Consistent with our resul ts, Alves (1990) found that, compared to
nearby Atlantic forest, plantations of shade-grown cacao supported lower
abundance of antbirds (Formicariidae and Thamnophilidae), tinamous (Ti-
namidae), and manakins (Pipridae), most of which are forest floor and
understory species. However, our study at the species-level revealed some
interesting differences that would not have been detected in the family level
study. For example, although both studies found that tyrant-flycatchers (Ty-
rannidae) as a family were at least as abundant in the shade-grown crops as in
the forest (see Appendix 1), our study found that only tyrant-flycatchers of the
forest canop y and forest edge wer e more abundant in the plantation than
the forest, while flycatchers of the forest floor and understory were absent from
the plantation. Despite differences between species for several fami lies, our
results support the general conclusions of Alves’ (1990) study that, although
some forest species are absent, birds are abundant in shade-grown cro ps with
native trees, adjacent to native Atlantic forest.
Compared to most other studies of birds in shade-grown crops (Greenberg
et al. 1997a,b; Calvo and Blake 1998), our study revealed a higher proportion of
forest birds in the plantation. In large part, this may be explained by the
proximity of native forest to our plantation. Surveys in plantations within
deforested landscapes rarely nd birds associated with interior forest (Greenberg
et al. 1997a,b; Calvo and Blake 1998). In contrast, near large tracts of natural
forest, other studies have found between 25 and 62% of forest bird species in
shade-grown crops (Terborgh and Weske 1969; Thiollay 1995; Canaday 1997).
While proximity to native forest is important, several other factors also play a role
in determining the bird diversity of plantations. High canopy cover and tree density,
for instance, may allow more forest birds to use a shade-grown crop (Greenberg
et al. 1997b; Calvo and Blake 1998). Contrary to this observation, we found that
forest birds (other than a few midstory and understory birds) were more common in
the plantation subplot with lower tree density, suggesting that, at the tree densities
we studied, high canopy cover and tree density were less important than other
factors in allowing Atlantic forest birds to use the shade-grown yerba plantation.
Other authors have predicted that forest birds will be most abundant
in plantations with structural and floristic diversity and abundant edible fruit
(Moguel and Toledo 1999; Rice and Greenberg 2000), We find support
for these hypotheses when we consider the combined results of several field
studies, including ours. Plantations with structural and floristic diversity
and abundant edible fruit (incl uding plantations, like ours, where the canopy
consisted of remnant forest trees; Alves 1990; Greenberg et al. 1997b;
Calvo and Blak e 1998) tend to support a greater diversity of birds, particularly
canopy frugivores, compared to less diverse plantations without fruit (Thiollay
1995; Cal vo and Blake 1998).
Management considerations
Although the shade-grown yerba plantation did not support forest understory
or midstory birds, it co ntained nearly all of the canopy- and tree trunk species
from the nearby forest, including five globally threatened and near-threatened
species. These results suggest that shade-grown yerba mate may be an
appropriate land-use for buffer zones around reserves in the Atlantic forest.
Our study considered only one plantation, and, therefore, we do not know
whether our results can be generalized. That said, the Atlantic forest requires
urgent conservation action, so we suggest an ‘adaptive management’ approach
to shade-grown yerba mate.
Shade-grown yerba mate could be especially beneficial, and less damaging to
existing forest, if used to rehabilitate some of the land that has already been
deforested, including plantations of yerba mate currently grown in the open.
Planting a wide diversity of native forest trees might return some of the
structural complexity and floristic diversity of natural forest to previously
cleared land, allowing forest birds to re-colonize areas from which they are
currently excluded. Agronomically this appears to be feasible. Eibl et al. (2000)
found promising yields for yerba mate grown alongside native tree seedlings on
abandoned agricultural land, and another study is underway to explore the
costs of reforestation with yerba mate and other native trees, on land adjacent
to Iguazu´ National Park in Argentina (S. Holz, in litt.).
In our plantation, a high tree density subplot (343 stems/ha; 80% canopy
cover) did not support more forest birds than a low tree density subplot (137
stems/ha; 50% canopy cover), suggesting that increasing canopy cover beyond
certain levels may not lead to increased abundance or diversity of forest birds.
Further studies in the Atlantic forest should aim to confirm or refute these
results, and to examine other ways to increase the bird conservation value of
shade-grown crops.
We especially thank R. Clay, M. Vela
zquez, and H. del Castillo, for help with
background information, project planning, and logistics, and A. Horn,
I. McLaren, B. Freedman, C. Staicer, R. Cavalcanti, and anonymous review-
ers, for helpful comments on the manuscript. R. Ribon and S. Holz provided
copies of their unpublished reports and articles in press. We thank Chololo
SRL and Guayakı
Yerba Mate for logistical support and access to the field site.
The project was financed by an Innovative Research Grant from the Canadian
International Development Agency, a Bergstrom Memorial Research Grant
from the Association of Field Ornithologists, an NSERC post graduate
scholarship with a 5NR supplement, a grant to KC from the Patrick Lett
Fund, and an NSERC Discovery grant to ML.
Appendix 1. List of species detected in the plantation and forest, with habitat groups, strata groups, diet groups, special conservation status, presence/
absence in the plantation and forest, estimated density in each habitat, and total number of encounters in each habitat.
IUCN Status
(endemic spp.)
Presence and density
N territories/100 ha
(N territories total)
Total N birds
within 100 m of
Forest Plant’n Forest Plant’n
Tinamus solitarius
f f LR/nt(e) Occasional 00
Crypturellus obsoletus f f 23(22) 78 0
Crypturellus parvirostris e Occasional 0 0
Crypturellus tataupa ff ++ 432
Coragyps atratus
Cathartes aura
e + Occasional 4 1
Sarcoramphus papa
fcc + 40
Leptodon cayanensis
fcc ++ 11
Elanoides forficatus
a + * 23 138
Harpagus diodon
fci ++ 22
Ictinia plumbea
Geranospiza caerulescens
f c c Occasional 10
Buteo magnirostris e (1) 1 20
Micrastur ruficollis f m c (4) 40
Micrastur semitorquatus f c c (3) (1) 2 3
Falco sparverius
e 2(2)* 0 20
Penelope superciliaris
fm + 10
Odontophorus capueira f f (e) Occasional 00
Aramides saracura f f i (e) Occasional 00
Columba speciosa f c fg (1) 11 0
Columba picazuro f c fg + + 22 153
Columba cayennensis f c fg + + 24 38
Zenaida auriculata e Occasional 0 2
Claravis pretiosa
fffg ++ 33
Leptotila verreauxi f f fg + + 7 21
Leptotila rufaxilla f f fg + 30
Geotrygon montana
f f fg + 30
Aratinga leucophthalmus f c fg + * 104 76
Pyrrhura frontalis f c fg + * 212 411
Forpus xanthopterygius e +016
Brotogeris chiriri e Occasional + 2 69
Pionopsitta pileata f c fg (e) + + 12 10
Pionus maximiliani f c fg + * 66 275
Amazona vinacea f c fg EN(e) + + 13 175
Coccyzus euleri f c i Occasional Occasional 0 0
Coccyzus melacoryphus
e Occasional 0 1
Piaya cayana fci ++ 5422
Crotophaga major f m i Occasional 40
Crotophaga ani e (1 group) 0 23
Guira guira e (2 grps) 0 26
Dromococcyx phasianellus
fui + 10
Dromococcyx pavoninus
fui + 20
Tyto alba e++01
Otus choliba f m i 5(2) 10(5)* 16 43
Otus atricapillus
f m i 12(4) + 17 1
Appendix 1. Continued.
IUCN Status
(endemic spp.)
Presence and density
N territories/100 ha
(N territories total)
Total N birds
within 100 m of
Forest Plant’n Forest Plant’n
Strix hylophila f c c Occasional 00
Strix virgata f c c (2) 10
Strix huhula f c c (1) 20
Glaucidium brasilianum f m i 8(10) 12(7) 43 36
Nyctibius aethereus
f c i (1) 00
Nyctibius griseus fci ++ 86
Lurocalis semitorquatus a++4571
Nyctidromus albicollis e +04
Caprimulgus sericocaudatus f c i Occasional 00
Cypseloides fumigatus a Occasional 0 1
Streptoprocne zonaris a Occasional 0 1
Chaetura cinereiventris a + + 29 140
Chaetura meridionalis a +033
Phaethornis eurynome
fmn ++ 6630
Anthracothorax nigricollis
e Occasional 0 1
Stephanoxis lalandi
f m n (e) + + 26 6
Chlorostilbon aureoventris
e +02
Thalurania furcata
fmn +22
Thalurania glaucopis
f m n (e) + + 14 4
Hylocharis chrysura
Agyrtria versicolor
fmn ++ 21
Trogon rufus f m (6) + 48 3
Trogon surrucura f c + * 114 124
Baryphthengus ruficapillus f m i (e) + Occasional 52 6
Momotus momota f m i (1) 60
Notharchus swainsoni
f c i (e) + * 7 15
Nystalus chacuru e Occasional 0 4
Nonnula rubecula
f m i + Occasional 15 1
Pteroglossus castanotis f c fg (3 grps) (2 grps)* 78 96
Selenidera maculirostris f c fg (e) (2) (1) 35 14
Ramphastos dicolorus f c fg (4 grps) (2 grps)* 19 27
Picumnus temminckii
f u i (e) + + 24 5
Melanerpes candidus e Occasional 0 0
Melanerpes flavifrons f c + + 23 176
Veniliornis spilogaster f m i (e) + + 18 67
Piculus aurulentus f c i LR/nt (e) + + 8 2
Colaptes melanochloros fti ++ 325
Celeus flavescens
fti +* 511
Dryocopus galeatus
f t i VU (e) + + 1 1
Dryocopus lineatus
fti +* 212
Campephilus robustus
f t i (e) + + 5 18
Synallaxis ruficapilla
f u i (e) 24(7) 117 0
Synallaxis cinerascens f u i 11(7) 69 0
Cranioleuca obsoleta f c i (e) Occasional Occasional 1 2
Syndactila rufosuperciliata f u i Occasional Occasional 4 4
Philydor lichtensteini f m i (e) + + 228 75
Philydor rufus fci ++ 197
Philydor atricapillus f m i (e) + 30
Automolus leucophthalmus f u i (e) 2(2) 32 0
Sclerurus scansor f f i (e) (1) 50
Heliobletus contaminatus f c i (e) + Occasional 3 1
Appendix 1. Continued.
IUCN Status
(endemic spp.)
Presence and density
N territories/100 ha
(N territories total)
Total N birds
within 100 m of
Forest Plant’n Forest Plant’n
Xenops minutus fmi + 14 2
Xenops rutilans fci ++ 2012
Dendrocincla turdina f t i (e) + 90
Sittasomus griseicapillus f t i + + 237 175
Xiphocolaptes albicollis fti +* 5736
Dendrocolaptes platyrostris fti +* 9079
Lepidocolaptes fuscus fti ++ 507
Lepidocolaptes falcinellus fti +01
Mackenziaena severa f u i (e) + 37 0
Thamnophilus caerulescens f u i 17(9) Occasional 159 2
Dysithamnus mentalis f u i 19(12) 196 0
Herpsilochmus rufimarginatus f c i + + 221 6
Terenura maculata f c i (e) + + 71 4
Pyriglena leucoptera f u i (e) + 70 0
Chamaeza campanisona ffi + 41 0
Grallaria varia ffi + 30
Conopophaga lineata f u i (e) 42(15) 190 0
Mionectes rufiventris f u (e) 1(1) 50
Leptopogon amaurocephalus f u i 5(3) 33 0
Hemitriccus diops
f u i (e) 16(5) 85 0
Corythopis delalandi f f i 4(2) 30 0
Phyllomyias virescens
f c i (e) + + 3 6
Camptostoma obsoletum f c + 3(1)* 4 36
Capsiempis flaveola
f u i 15(3) 34 0
Myiopagis caniceps f c i + + 125 94
Myiopagis viridicata fci ++ 82
Elaenia flavogaster e Occasional 0 1
Elaenia albiceps
e Occasional 0 1
Phylloscartes eximius f m i LR/nt(e) + 20
Phylloscartes ventralis
fci + 20
Phylloscartes sylviolus
f c i LR/nt(e) + (1)* 3 25
Myiornis auricularis
f u i (e) 67(16) 7(2) 236 10
Tolmomyias sulphurescens fmi ++ 94
Platyrinchus mystaceus f u i 21(7) 141 0
Cnemotriccus fuscatus
fui + 60
Lathrotriccus euleri f u i 11(9) Occasional 109 2
Contopus cinereus f c i 1(1) 8(4)* 10 80
Colonia colonus e + 4(2)* 2 22
Sirystes sibilator fci ++ 4791
Myiarchus swainsoni e++229
Myiarchus ferox e Occasional 0 1
Ramphotrigon megacephala f m i (1) 60
Tyrannus melancholicus e Occasional 0 3
Empidonomus varius
e +08
Megarynchus pitangua e + 18(12)* 12 168
Conopias trivirgata fci ++ 2545
Myiodynastes maculatus e 2(1) 18(8)* 12 139
Myiozetetes similis e 2(1) 0 7
Legatus leucophaius
e *05
Pitangus sulphuratus e 1(1) 29(14)* 16 342
Schiffornis assemblage
Schiffornis virescens f m (e) (4) 48 0
Piprites chloris fm ++ 544
Pachyramphus viridis e++1352
Pachyramphus castaneus e+*374
Appendix 1. Continued.
IUCN Status
(endemic spp.)
Presence and density
N territories/100 ha
(N territories total)
Total N birds
within 100 m of
Forest Plant’n Forest Plant’n
Pachyramphus polychopterus e Occasional 0 1
Pachyramphus validus e +011
Tityra cayana f c + + 58 124
Tityra semifasciata fc +03
Tityra inquisitor f c + * 48 136
Pyroderus scutatus
f c (e) Occasional 0 0
Oxyruncus cristatus fc ++ 3714
Pipra fasciicauda
f u (4) 36 3
Chiroxiphia caudata f m (e) (2) 14 0
Cyclarhis gujanensis f c i (3) + 39 3
Vireo olivaceus fci + 30
Cyanocorax cyanomelas e Occasional 0 0
Cyanocorax chrysops f c + + 170 293
Progne chalybea a  55
Progne tapera a  33
Petrochelidon pyrrhonota a  04
Troglodytes aedon e 48(20) 0 412
Polioptila lactea
f c i LR/nt(e) + + 8 16
Turdus subalaris
f c (e) + 10
Turdus rufiventris e++825
Turdus leucomelas e + * 50 442
Turdus amaurochalinus e++87
Turdus albicollis fm ++ 41
Parula pitiayumi fci ++ 9170
Basileuterus culicivorus f u i 69(33) 9(3) 501 66
Basileuterus leucoblepharus f u i 21(12) 217 0
Conirostrum speciosum f c i + + 185 194
Cissopis leveriana fc ++ 4015
Hemithraupis guira f c i + + 333 238
Tachyphonus coronatus
f u Occasional 30
Habia rubica f u 4(3) 45 1
Trichothraupis melanops f u 15(8) 133 1
Thraupis sayaca e Occasional + 2 70
Pipraeidea melanonota
fc ++ 21
Euphonia chlorotica fc ++ 1681
Euphonia violacea fc ++ 3456
Euphonia pectoralis f c (e) + + 52 41
Chlorophonia cyanea
fc ++ 1426
Tangara seledon
f c (e) + + 10 60
Dacnis cayana
fc ++ 2546
Tersina viridis e + + 23 139
Coryphospingus cucullatus
e  10
Sporophila caerulescens e  01
Arremon flavirostris fffg  20
Zonotrichia capensis e  03
Appendix 1. Continued.
IUCN Status
(endemic spp.)
Presence and density
N territories/100 ha
(N territories total)
Total N birds
within 100 m of
Forest Plant’n Forest Plant’n
Cacicus haemorrhous f c + * 56 127
Icterus cayanensis e++1687
Gnorimopsar chopi e Occasional + 2 27
Molothrus bonariensis e Occasional 0 1
Molothrus oryzivorus e Occasional 0 1
Molothrus rufoaxillaris e +09
Taxonomy follows Mazar Barnett and Pearman (2001).
Species whose vocalization cannot be heard consistently 100 m away.
Species that vocalize infrequently during the time of year covered by our study seasons.
Habitat groups are: f = forest; e = edge, a = aerial.
Strata groups (for forest birds only) are: c = canopy, m = midstory, u = understory, f = forest floor, t = tree trunk.
Diet groups (for forest birds only) are: fg = fruit-or-grain-eater, = fruit-and-insect-eater, i = insectivore, n = nectarivore, c = carnivore or carrion-eater.
IUCN conservation status follows IUCN (2002). EN = endangered, VU = Vulnerable, LR/nt = lower risk / near-threatened.
Species endemic to the Atlantic forest are marked (e). We follow Guyra Paraguay (2004).
Presence (in the main plots) is indicated by +, the estimated density, the total number of territories, or* (see below). Species considered absent are marked if
they were never recorded in the habitat, or ‘occasional’ if they were occasional visitors to the habitat. We report the total number of territories and estimated
density only for species for which these numbers could be determined in both habitats.
* Species confirmed breeding in the habitat (active nests, adults repeatedly carrying nest material or food to the same tree, or newly fledged young within a
known territory)
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... Ilex paraguariensis A. St.Hil., Aquifoliaceae ("yerba mate") is a native tree from South America whose leaves are used to prepare an infusion or tea of popular consumption with a market expanding internationally, as yerba mate is nutritious, energizing, and it contains antioxidants Agriculture, cattle-ranching, and industry have replaced much of the Atlantic forest, and its diverse fauna is threatened by high grade logging, hunting, habitat loss, and habitat fragmentation (Cockle et al. 2005;Brewer 2011). ...
... Organic yerba mate growing with the native tree Enterolobium contortisiliquum (timbo), a valuable nitrogen fixing tree. (Photo: F. Montagnini) With yerba mate being one of the Atlantic forest region's most widespread crops, it is important to ascertain how these trees can be used by fauna in the region and how plantations may be managed to promote conservation (Cockle et al. 2005). These authors compared bird species' presence and abundance between a forest reserve and an adjacent plantation of shade-grown yerba mate in Paraguay. ...
... Within the yerba mate AFS, higher tree density did not lead to a greater abundance of forest birds. The authors conclude that yerba mate AFS with native trees could be used to rehabilitate cleared land and allow recolonization by some Atlantic forest bird species (Cockle et al. 2005). While these results are encouraging, it would be interesting to compare bird abundance and diversity in this type of yerba mate AFS with other modalities for cultivating yerba mate in the region. ...
Biodiversity islands can contribute to protect biodiversity in human-dominated landscapes. Agroforestry systems (AFS), as they can harmonize productivity with environmental functions, can be part of biodiversity islands, especially in the buffer zones of protected areas. AFS are heterogeneous in their design and management, with consequences for their restoration and conservation functions. This chapter discusses the role of AFS on restoration and conservation of biodiversity at the ecosystem and landscape levels, with emphasis on tropical Latin America and examples from other regions.
... Despite of being usually produced as a monoculture, shadegrown yerba mate systems have been encouraged among communities as an alternative to promote forest conservation while meeting their economic needs (Ferreira & Salas-Dueñas 2019). Cockle et al. (2005) analysed the potential for shade-grown yerba mate to conserve Atlantic Forest's birds in the Canindey u department in Paraguay. The authors found that although some forest species are absent, birds are abundant in shade-grown crops with native trees, adjacent to native Atlantic Forest. ...
... Point counts at the edge were located approximately at 50 m inside within the limit of the forest and croplands (CP). Birds were categorised into functional groups using diet and foraging stratum (understory species include those that use low and medium stratum) based on literature and field observations, following Sick (1993), Stotz et al. (1996), Cockle et al. (2005) and Ara ujo et al. (2016). The following categories were used: frugivores, insectivores, canopy species or understory species. ...
... Overall, our research shows that bird richness is higher inside the forests with shade-grown yerba mate, than at the edge or in monoculture croplands. These results imply that shade-grown yerba mate plantations allow the maintenance of the diversity of bird species richness at some level, with a positive impact, making this activity a suitable strategy for sustainable production and forest recovery (Cockle et al. 2005). Also, this indicates that productive landscapes can be managed to maintain native biodiversity (Faria et al. 2007;Pardini et al. 2009), providing economic viable alternatives for local communities. ...
Native Ilex paraguariensis (yerba mate) is one of the most widespread crops in the Atlantic Forest region of southern South America and has an important economic and cultural value in Paraguay, Argentina, Brazil and Uruguay. Despite the known potential of shade-grown products (especially cocoa and coffee) to protect biodiversity, the benefits of shade-grown yerba mate for biodiversity conservation in the Atlantic Forest remain scarce, one of the most threatened ecoregions in the world, also considered a biodiversity hotspot. In order to understand these potential benefits, it is important to identify how species use shade-grown yerba mate plantations, as well as if it can be an strategy to improve or maintain biodiversity in complex socio-ecological landscapes. We analyzed the potential benefits of forests with shade-grown yerba mate for birds, amphibian and reptiles in the Reserve for National Park “San Rafael” and its buffer area (Itapúa Department, Paraguay). We evaluated differences in species richness and composition between three environments: forest with shade-grown yerba mate, forest edge and monoculture crop plantations analyzing beta diversity. A total of 112 bird species were recorded in all three environments. Regarding the herpetological community, we recorded 10 species (seven amphibians and three reptiles). Our results indicate that forests with yerba mate plantations not only maintains the bird species richness, but also its species composition differs significantly from edge and croplands, which might be an indicator of the contribution of shade-grown yerba mate plantations to conservation. The results of the research would help to value the impact of sustainable agroforestry activities for the conservation of Atlantic Forest biodiversity.
... Agriculture, cattle-ranching, and industry have replaced Eibl et al. 2017). Photo: F. Montagnini much of the Atlantic forest, and its diverse fauna is threatened by high grade logging, hunting, habitat loss, and habitat fragmentation (Cockle et al. 2005;Brewer 2011). ...
... Within the yerba mate AFS, higher tree density did not lead to a greater abundance of birds. Yerba mate AFS under native trees could therefore be used to rehabilitate cleared land and allow recolonization by Atlantic forest bird species (Cockle et al. 2005). ...
... Some protected areas are Sustainable Management Resources Reserves (239 km 2 ), where 50% of the surface of the reserve are allowed to be managed for economic benefits, including agriculture, shade-grown plantations, or harvesting timber or non-timber products in the forest. While comparing the bird community in a shade-grown yerba mate plantation with the forest in one of the core areas, Itabó Biological Reserve, only 66% of the species of the forest were present in the plantation, being the understory, forest floor, and mid-story species more restricted to the forest; 40% of the species that were present in both habitats were two times more abundant at the forest, and five of the seven threatened species found in the forest were present at the plantation [41]. These results suggest that this sustainable activity does have lower impact in the forest bird community than traditional plantations and could be beneficial if used to rehabilitate some of the deforested areas, including areas where yerba mate is grown in the open [41]. ...
... While comparing the bird community in a shade-grown yerba mate plantation with the forest in one of the core areas, Itabó Biological Reserve, only 66% of the species of the forest were present in the plantation, being the understory, forest floor, and mid-story species more restricted to the forest; 40% of the species that were present in both habitats were two times more abundant at the forest, and five of the seven threatened species found in the forest were present at the plantation [41]. These results suggest that this sustainable activity does have lower impact in the forest bird community than traditional plantations and could be beneficial if used to rehabilitate some of the deforested areas, including areas where yerba mate is grown in the open [41]. The effects of selective logging on the bird community is still not evaluated at the UPAF in Paraguay, being one of the objectives of the censuses developed in this study. ...
Full-text available
The Atlantic Forest, one of the most biodiverse biomes in the world, is also one of the most endangered. In Paraguay, its remnants are mostly fragmented and isolated. The Paraguay Biodiversity Corridor is an initiative that is being developed to generate and maintain connectivity of the main conservation areas. With the objective to analyze the bird richness and occurrence in each of the core areas of this corridor, we gathered published data, details of the management plans, and bird surveys recorded during 2015 and 2017 in these areas. In total, 557 bird species occur in the core areas of the Corridor, representing more than 80% of the birds of the country. San Rafael National Park and Mbaracayú Forest Nature Reserve are the richest areas, with 427 (70) and 408 (61) bird species (Atlantic forest endemics), respectively. These two areas also harbor more than 30 bird species of global conservation concern. Only 24% of the Corridor area is protected or sustainably managed, with only 10% under strict protection. The Corridor situated within this endangered biome encompasses some of the most important areas for bird conservation, but the situation of many of these areas is alarming as they are not protected or effectively managed to conserve their biodiversity. Restoration of connectivity, legal enforcement, and strengthening of authorities to combat deforestation on core areas, along with research focused on the impact contributed by human activities (selective logging, ecotoxicity exposure to agrochemicals) are key actions prioritized for the Upper Parana Atlantic forest (UPAF) Corridor.
... As a result, several Paraguayan NGOs, including the Fundacion Moises Bertoni and Guyra Paraguay, have positioned the Atlantic forest at front and center of their conservation efforts. Through these efforts, the idea emerged that shade-grown yerba mate can be an ecologically sound alternative in forest remnants (Cabral et al., 2020;Cockle et al., 2005) and serve as a counterweight to expansion on the extensive margin. ...
Purpose This study explores the determinants of growth of credence-based exports of yerba mate from Paraguay, potential for increased export growth, and the fragility of the credence-based export model. Much of the growth in value of yerba mate exports from Paraguay is due to positioning of the good within the universe of products where consumption is driven by perceptions of sustainable production and health benefits to consumers. Credence claims for yerba mate—benefits to indigenous producing communities, environmental sustainability under certain production processes, healthful alternatives to energy drinks—are now widely known, but the growth of this awareness came via a new entrepreneurial strategy of a single firm. Design/methodology/approach Primary information was collected through interviews of actors in the Paraguayan yerba mate value chain during spring/summer 2020. These included representatives from three exporting companies, processors, public institutions and indigenous producers. Findings The Paraguayan yerba mate export boom was stimulated through the careful cultivation of an image of healthful consumption and sustainable production processes. The cost of this cultivation was borne mainly by a single firm. Findings suggest that future marketing efforts will need to reinforce credence claims, highlighting the benefits to indigenous producers. Research limitations/implications This case study explores the determinants of growth of credence-based exports of yerba mate from Paraguay, potential for increased growth, and the fragility of the credence-based model. Originality/value Findings are supported by field interviews with value chain participants and detailed analysis of extant data. The paper is the first to discuss the fragility of relying on credence attributes for long-term demand growth.
... Different types of agroforestry systems, including silvopastoral systems, have been reported to contribute to the conservation of birds in agricultural landscapes in the tropics (Cockle et al., 2005;Faria et al., 2006;Gómez and García, 2014;Greenberg et al., 1997;Komar, 2006), but their effectiveness depends on the existence of surrounding forest remnants (Aerts et al., 2017;Greenler and Ebersole, 2015;Norfolk et al., 2017). In silvopastoral systems, birds provide biological pest control, eating cattle parasites frequently found in pastures (Sujii et al., 2004), while also pollinating native vegetation and dispersing seeds in and from surrounding forest (Gómez and García, 2014). ...
The quality of a landscape's matrix is a key condition for the conservation of biodiversity and affects the diversity and composition of bird assemblages in agricultural landscapes with forest remnants. In southern Brazil most agricultural landscapes are a mosaic of cultivated areas, treeless pastures and forest remnants. These landscapes must be planned and managed for food production while synergically enhancing ecological restoration and biodiversity conservation. In this study, we compared the diversity and composition of bird species in High Biodiversity Silvopastoral Systems (SPSnuclei), treeless pasture areas, forest edges and forest interiors. SPSnuclei is a type of silvopastoral system (SPS) whose design was inspired by applied nucleation reforestation techniques using multispecies agroforestry nuclei. In this study, we sought to understand the influence of the SPSnuclei on the diversity and composition of birds by comparing SPSnuclei to treeless pasture areas, forest edges and the forest interior. We hypothesize that multispecies agroforestry nuclei would restore some of the ecosystem biodiversity, and therefore resilience. To quantify bird diversity, sound recorders were installed simultaneously within these habitats during the spring and summer of 2016 and 2017 on three dairy farms. We identified calls from 108 bird species in 2400 min of recordings (600 min/habitat). The High Biodiversity Silvopastoral System increased the diversity of birds in the agroecosystem. Species richness was higher in the parcels with SPSnuclei compared to treeless pastures (P < 0,05). Although, species richness was smaller in the SPSnuclei than forest edge and interior of the forest remnants (P < 0,05). Eight species from the interior and forest edge were observed in the SPSnuclei, but not in the treeless pastures. This research presents evidence that SPSnuclei has positive effects on the diversity and composition of the avifauna in agricultural landscapes and could act as stepping stones that increase connectivity between forest remnants.
... Esto implica, en parte, reconocer que algunas actividades productivas son más compatibles que otras con la conservación de la biodiversidad. Además, como camino hacia la sustentabilidad, se deberían fomentar sistemas agroforestales que incluyan el uso del bosque entre los pequeños y medianos productores, y sistemas de producción intensiva que sean permeables a la flora y la fauna nativas (e.g., plantaciones de yerba mate con árboles nativos) (Cockle et al. 2005;Eibl et al. 2017), o también plantaciones forestales en superficies reducidas y con turnos de por lo menos 18 a 20 años de corta y manejos tendientes a aumentar la diversidad en el sotobosque (Dummel and Pinazo 2013;Zurita et al. 2006;Ritter 2017;Trentini et al. 2017). Un sistema agroforestal exitoso en Brasil es el cultivo de yerba mate orgánica bajo el bosque (Marques 2014). ...
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Para conservar una superficie representativa de los bosques subtropicales de Misiones (Argentina), ecosistema amenazado a nivel mundial, es necesario encontrar una solución económicamente viable a las superficies que hoy, y de acuerdo con la Ley 26331, sólo se pueden destinar al manejo sostenible del bosque nativo, así como a disminuir la deforestación en las áreas pasibles de ser reemplazadas (901617 ha y 477858 ha, respectivamente, de acuerdo con el último ordenamiento territorial realizado por la Provincia de Misiones). La deforestación, que ocurre desde mediados del siglo pasado, fue fomentada por políticas públicas de incentivos a actividades de producción intensivas como las plantaciones forestales u otros cultivos. Los bosques remanentes están degradados por la explotación de las principales especies nativas comerciales en ciclos de corta menores a 20 años, y la productividad maderera es más baja de lo necesario para sostener económicamente la actividad. En algunos casos, la productividad podría recuperarse con manejos post-extracción (e.g., el corte de bambúes y lianas), mientras que, en situaciones de mayor degradación, se necesitan acciones de manejo más intensivas como la escarificación de los suelos o la plantación de renovales de especies de alto valor comercial y rápido crecimiento que permitan turnos de corta de 30 años e incrementos de al menos 3 m3.ha-1.año-1. Asimismo, se necesita una política de control del comercio ilegal de madera nativa, que disminuye los precios y reduce la rentabilidad de productores responsables. Por otra parte, la obtención de madera debería complementarse con reducciones impositivas, por ejemplo, a través de la compensación por provisión de servicios ecosistémicos, o mediante otros tipos de usos, como el aprovechamiento de recursos no madereros. En el caso de pequeños y medianos productores, el gobierno y ONG deberían estimular la conservación del bosque por el uso de sus recursos y servicios ambientales, incentivar activamente la diversificación de la producción y brindar las herramientas que les permitan a los productores independizarse del cultivo intensivo de tabaco. Es necesario un mayor financiamiento directo a los productores para el manejo, así como a organismos dedicados a generar conocimiento que permita avances concretos en el manejo sostenible del bosque.
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Recopila las memorias de la primera década de vida de la Fundación Azara (2000-2010).
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Yerba mate, Ilex paranguariensis, is a shrub commonly found in the Atlantic Forest of South America which covers part of northeast Argentina, eastern Paraguay, and southern Brazil. The dried leaves and stem of the tree are used to make an infusion, called mate, used first by indigenous Guaraní people. Today, yerba mate is widely consumed in the Southern Cone region and is regarded as the national drink of Argentina, Paraguay, and Uruguay. I argue that yerba mate has entered the U.S. as a “superfood,” marketed as a product with nutritional and symbolic medicinal values. In this thesis, I trace yerba mate’s construction as a symbol of Argentine national identity which entailed both the exploitation of indigenous labor and erasure of the mate’s indigenous roots. I show that this history continues to be relevant for understanding the meaning of yerba mate today in Argentina. I focus specifically on two successful yerba mate brands, Taragui and Titrayju. Drawing on a semiotic analysis of product packaging and a discourse analysis of contemporary media narratives on yerba mate, I situate these brands within a larger historical context. I then follow yerba mate transnationally with an analysis of its more recent marketing to U.S. consumers. I focus on the most popular yerba mate brand, Guayakí, that markets yerba mate as a superfood and as a socially and environmentally sustainable product to young consumers. Despite different yerba mate narratives across the Americas, as a national symbol and as a transnational superfood, very similar historical processes continue to undermine indigenous rights and identity in both its place of origin and in its new U.S. market.
Although biodiversity is in sharp decline around the globe, collectiing precise information on changes in overall species richness remains extremely challenging. Efficient and reliable proxy methods are therefore needed, with the diversity of higher taxa representing one such potential proxy for species‐level diversity. Nonetheless, the stability of using this measure across different regions and animal taxa at the global scale has never been investigated thoroughly. Global. Up to 2016. Animalia. We used a large global dataset containing published studies on diversity in the terrestrial Animalia to analyse the relationship between diversity at the family, genus and species level across different orders. Family and species diversity were positively correlated, with the strongest correlations in Diptera, Hemiptera and Coleoptera. Correlations were slightly weaker in family–species than in genus–species relationships, whereas differences were stronger in observed richness than in diversity indices. Across all taxa, family–species correlations of Shannon diversity index values were independent of sample size, and they showed limited variation across biomes for the three orders containing sufficient case studies for this analysis. Based on the Shannon diversity index, the species diversity per site increased linearly with the increase in family diversity, with an average species : family diversity index ratio of 2.5, slightly lower than the ratio of 2.7 for observed species and family richness values. Our study confirmed that recording family‐level diversity can be a meaningful proxy for determining species‐level diversity patterns in biodiversity studies, and trade‐offs between identification costs and retained information content need to be considered when using higher taxon surrogacy.
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I evaluated the effects of selective logging upon a bird community in the Brazilian Atlantic forest. Two areas 500 m apart were selected for quantitative (point censuses) avian surveys: a non-fragmented primary forest (PF) and a selectively logged forest (LF). Six of eight quantitative measures of vegetation structure compared between PF and LF were reduced at LF. Indices of avian species richness and diversity were very similar between PF and LF sites; species composition, however, differed strongly. Although the composition of guilds remained largely the same, most guilds differed in membership between PF and LF in at least one species. Understory and terrestrial insectivores were the most sensitive ecological groups (with most species missing in LF), as also observed in the process of forest fragmentation in other parts of the Neotropics. Based on the results of this study, I recommend the following procedures to minimize adverse effects of selective logging on bird communities in the Atlantic forest: (1) logged areas should be close enough to unfragmented, unlogged forests to allow recolonization of some species, (2) the exploitation of the forest should be carded out using as few roads and as little mechanized equipment as possible, and (3) long-term rotation should be used in areas designed for logging to allow time for forest regeneration.
Complete surveys of the bird faunas of 4- to 10-acre study plots in six habitats were undertaken at a locality in the Apurímac Valley of Peru. Two of the habitats, forest and matorral, represent the primary vegetation of the region. Four secondary habitats incorporated varying degrees of departure from the structure and species composition of natural vegetation. Of the 211 species of land birds found in the 6 habitats, all but 10 were recorded in at least of the 2 primary habitats. With the exception of these 10 species the fauna of the secondary habitats was drawn from 3 species pools: forest, martorral and species common to both. The proportions of forest and matorral species in the secondary habitats varied greatly in relation of the vegetation of the habitats and their proximity to the source faunas. Mist nets were used in all the study plots to sample the using the airspace between 6 in. and 6 ft above the ground. The species diversity in samples of 100, calculated according to the Shannon-Wiener formula, showed rather little variation from one habitat to another. Of greater interest was the fact that in most nests caught fewer than half of the species known to be present. In temperature habitats virtually all species are eventually captured. This contrast is considered to reflect a fundamental difference in the spatial relationships of bird niches in temperate and tropical forests. The above and other evidence indicate that many tropical bird species confine their foraging activities to narrow vertical zones in the vegetational column. The number of bird species in the four secondary habitats was much lower than in primary habitats having similar foliage height profiles. The discrepancies are accounted for by an hypothesis that evokes two complementary parameters: the isolation of tracts of secondary habitat from primary vegetation and certain qualitative aspects of habitat that are not adequately expressed by the foilage height diversity index.
To help fill the gap in detailed knowledge of avian community structure in tropical forests, we undertook a census of a 97-ha plot of floodplain forest in Amazonian Peru. The plot was censused over a 3-mo period spanning the 1982 breeding season. The cooperative venture entailed @?12 person-months of effort. Conventional spot-mapping was the principal method used, but several additional methods were required to estimate the numbers of non-territorial and group-living species: direct counts of the members of mixed flocks, saturation mist-netting of the entire plot, opportunistic visual registrations at fruiting trees, determination of the average size of parrot flocks, color banding of colonial icterids, etc. Two hundred forty-five resident species were found to hold territories on the plot, or to occupy all or part of it. Seventy-four additional species were detected as occasional-to-frequent visitors, wanderers from other habitats, or as migrants from both hemispheres. By superimposing territory maps or the areas of occupancy of individual species, we determined that point (alpha) diversities exceeded 160 species in portions of the plot. About 1910 individual birds nested in 100 ha of this floodplain forest, making up a biomass conservatively estimated at 190 kg/km^2. The total number of breeding birds was equivalent to that in many temperate forests, but the biomass was about five times as great. Predominantly terrestrial granivores contributed the largest component of the biomass (39%), followed by largely arboreal frugivores (22%). Considering only insectivores, the biomass (34 kg/km^2) is somewhat less than that in the forest at Hubbard Brook, New Hampshire (40 kg/km^2), although it is greater (55 kg/km^2) if one includes omnivores. The number of insectivores was considerably less than at Hubbard Brook, due to their 60% larger average body size (32 vs. 20 g). Even though a large majority of the species were patchily distributed, the 97-ha plot was found to include 99% of the bird species that regularly occupy mature floodplain forest at Cocha Cashu. The most abundant species occupied territories of 4-5 ha, and 84 species (26%) had population densities of @<1 pair per square kilometre. Of these, 33 (10% of the total community) were judged to be constitutively rare (i.e., having low population densities everywhere), rather than being merely locally rare. Many of these are predicted to be vulnerable to forest fragmentation and disturbance. Comparison of these results with those from other tropical forests proved difficult due to a lack of standardized methodology.
Much of the remaining “forest” vegetation in eastern Chiapas, Mexico is managed for coffee production. In this region coffee is grown under either the canopy of natural forest or under a planted canopy dominated by Inga spp. Despite the large differences in diversity of dominant plant species, both planted and rustic shade coffee plantations support a high overall diversity of bird species; we recorded approximately 105 species in each plantation type on fixed radius point counts. We accumulated a combined species list of 180 species on repeatedly surveyed transects through both coffee plantation types. These values are exceeded regionally only by moist tropical forest. Of the habitats surveyed, shade coffee was second only to acacia groves in the abundance and diversity of Nearctic migrants. The two plantation types have similar bird species lists and both are similar in composition to the dominant woodland—mixed pine-oak. Both types of shade coffee plantation habitats differ from other local habitats in supporting highly seasonal bird populations. Survey numbers almost double during the dry season—an increase that is found in omnivorous migrants and omnivorous, frugivorous, and nectarivorous resident species. Particularly large influxes were found for Tennessee warblers (Vermivora peregrina) and northern orioles (Icterus galbula) in Inga dominated plantations.
We studied the avifauna of sun and shade coffee plantations and associated mid-elevation habitats during the dry season of 1995. The three plantation types (Inga, Gliricidia, and sun) showed high faunistic similarities with each other and were both distinct and depauperate compared to matorral and forest patch habitats. Of all the coffee plantation habitats, Inga shade had the highest diversity. Species associated with wooded vegetation were more common in shade plantations, particularly in Inga. A second census showed a decline in bird numbers that was more pronounced in sun and Gliricidia than in Inga plantations. Overall, differences between the plantation types were small and all coffee plantations were less diverse than traditional coffee farms previously studied in nearby Chiapas, México. The relatively low bird diversity was probably due to the low stature, low tree species diversity, and heavy pruning of the canopy. These features reflect management practices that are common throughout Latin America. The most common species of birds in all coffee plantation habitats were common second-growth or edge species; more specialized forest species were almost completely absent from plantations. Furthermore, many common matorral species were rare or absent from coffee plantations, even sun plantations with which matorral shares a similar superficial structure. Coffee plantations probably will only be important for avian diversity if a tall, taxonomically and structurally diverse canopy is maintained. We suggest this is most likely to occur on farms that are managed for a variety of products rather than those designated entirely for the production of coffee.