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Tinamous and agriculture: lessons learned from the Galliformes

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Resumen. – Tinámidos y agricultura: lecciones aprendidas de los Galliformes. – El 32% de las 47 especies del orden Tinamiformes viven en pastizales. Estas especies están distribuidas en las regiones tro-picales y templadas, pero la mayoría se encuentran en las regiones australes de América del Sur. Las pobla-ciones de estas especies son susceptibles a la conversión de la tierra para agricultura y la intensificación del uso de la tierra después de la conversión. Existe poca información sobre los efectos de la conversión y uso de la tierra en las poblaciones de tinamúes, pero hay mucha investigación sobre sus efectos en los Galliformes. Al considerar los tinamúes que viven en pastizales como los equivalentes ecológicos de los Galliformes, se pueden hacer inferencias generales sobre los posibles efectos de la conversión y inten-sificación del uso de la tierra en estas especies. Es más eficiente ver los impactos potenciales del uso de la tierra como una función de la interacción de múltiples gradientes: el área de la vegetación natural, la estructura de la vegetación, la intensidad de la agricultura y ganadería, y el uso de herbicidas y pesticidas. Este modelo permite una cuantificación de la conveniencia de un lugar para cada especie, flexibilidad potencial de las especies a los cambios de hábitat, la comparación entre lugares y funciona como una herramienta para determinar rápidamente el valor de conservación de los lugares en el paisaje. Abstract. – Species inhabiting grassland and steppes represent 32% of the 47 species of the order Tinami-formes. These species are both tropical and temperate in their distribution but the majority is confined to austral South America. Populations of these species are susceptible to land conversion for agriculture, as well as intensification of land use after conversion. Although little information exists on the effects of land conversion and use on tinamou populations, there is an extensive amount of research on these effects on gallinaceous birds. By viewing the grassland and steppe dwelling tinamous as ecological equivalents to the Galliformes, general inferences can be made about the projected impacts of land conversion and the inten-sity of use on these species. It is most efficient to view the potential impacts of land use as a function of the interaction of several gradients: area of natural vegetation, vegetation structure, intensity of cropping and grazing, and herbicide and pesticide use. This model allows for a quantification of site suitability by species, potential resilience of species, comparison among sites, and serves as a tool to rapidly assess the conservation value of sites within the landscape.
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301
ORNITOLOGIA NEOTROPICAL 15 (Suppl.): 301–307, 2004
© The Neotropical Ornithological Society
TINAMOUS AND AGRICULTURE: LESSONS LEARNED FROM
THE GALLIFORMES
Jeffrey J. Thompson
Daniel B. Warnell School of Forest Resources, University of Georgia, Athens, Georgia
30602-2152, USA. E-mail: perdiz@uga.edu
Resumen. – Tinámidos y agricultura: lecciones aprendidas de los Galliformes. El 32% de las 47
especies del orden Tinamiformes viven en pastizales. Estas especies están distribuidas en las regiones tro-
picales y templadas, pero la mayoría se encuentran en las regiones australes de América del Sur. Las pobla-
ciones de estas especies son susceptibles a la conversión de la tierra para agricultura y la intensificación del
uso de la tierra después de la conversión. Existe poca infor mación sobre los efectos de la conversión y
uso de la tierra en las poblaciones de tinamúes, pero hay mucha investigación sobre sus efectos en los
Galliformes. Al considerar los tinamúes que viven en pastizales como los equivalentes ecológicos de
los Galliformes, se pueden hacer inferencias generales sobre los posibles efectos de la conversión y inten-
sificación del uso de la tierra en estas especies. Es más eficiente ver los impactos potenciales del uso de
la tierra como una función de la interacción de múltiples gradientes: el área de la vegetación natural, la
estructura de la vegetación, la intensidad de la agricultura y ganadería, y el uso de herbicidas y pesticidas.
Este modelo permite una cuantificación de la conveniencia de un lugar para cada especie, flexibilidad
potencial de las especies a los cambios de hábitat, la comparación entre lugares y funciona como una
herramienta para determinar rápidamente el valor de conservación de los lugares en el paisaje.
Abstract. – Species inhabiting grassland and steppes represent 32% of the 47 species of the order Tinami-
formes. These species are both tropical and temperate in their distribution but the majority is confined to
austral South America. Populations of these species are susceptible to land conversion for agriculture, as
well as intensification of land use after conversion. Although little information exists on the effects of land
conversion and use on tinamou populations, there is an extensive amount of research on these effects on
gallinaceous birds. By viewing the grassland and steppe dwelling tinamous as ecological equivalents to the
Galliformes, general inferences can be made about the projected impacts of land conversion and the inten-
sity of use on these species. It is most efficient to view the potential impacts of land use as a function of
the interaction of several gradients: area of natural vegetation, vegetation structure, intensity of cropping
and grazing, and herbicide and pesticide use. This model allows for a quantification of site suitability by
species, potential resilience of species, comparison among sites, and serves as a tool to rapidly assess the
conservation value of sites within the landscape. Accepted 29 December 2003.
Key words: Tinamiformes, Galliformes, agriculture, grazing, agro-ecosystems, grasslands, gamebirds.
INTRODUCTION
Temperate and tropical grassland habitats
(grasslands, steppes, savannas) have been, and
continue to be, extensively converted for
grazing and row crops (from here on agricul-
ture) (White et al. 2000). Consequently, much
of the biodiversity from these natural ecosys-
tems is now associated with a landscape
matrix of varying complexity, consisting of
302
THOMPSON
natural and man modified habitats. Increas-
ingly, these agro-ecosystems have become less
diversified in content and complexity
(McNeely et al. 1995).
During the post-World War II era, grass-
land conversion and/or agricultural intensifi-
cation have increased in intensity and extent
(Fuller 2000). Although Europe and North
America have been placed under high-input
agriculture over the last half-century, other
areas such as South Africa and Argentina
have lagged behind until recently (Pero &
Crowe 1996, Viglizzo & Roberto 1998). This
process of land conversion and agricultural
intensification has been attributed to the glo-
bal declines of grassland and shrubland birds
(Aebischer et al. 1999, Vickery & Herkert
1999, Murphy 2003, Peterjohn 2003).
Among the grassland dependent birds, the
population declines of the gallinaceous game-
birds were some of the first to draw the atten-
tion of researchers and the public. The first,
and one of the most thorough studies into the
effects of farmland composition and manage-
ment on galliform populations was on the
declines of the Grey Partridge (Perdix perdix)
in England (Potts 1980, 1986). This research
highlighted the importance of the composi-
tion and configuration of the agricultural
landscape and how it is managed, particularly
the use of herbicides and pesticides. These
have become major themes in the research of
grassland birds (Vickery & Herkert 1999,
Aebischer et al. 2000, Murphy 2003, Peterjohn
2003) and have been key topics of research
for many gamebirds (Rands et al. 1988),
including Northern Bobwhite (Colinus virgi-
nianus; Brennan 1999), prairie chickens (Tym-
panuchus spp.; Fuhlendorf et al. 2002, Geisen
1998, Ryan et al. 1998), Helmeted Guineafowl
(Numida meleagris; Pero & Crowe 1996, Malan
& Benn 1999, Ratcliffe & Crowe 2001) and
francolins (Fra n colin us spp.; Little & Crowe
1998; Jansen et al. 1999, 2000).
Grassland tinamous (Tinamiformes) rep-
resent 32% of the 47 species and, in most of
South America, occupy the majority of niches
in grassland habitats associated with the galli-
forms in other regions (Davies 2002, del
Hoyo 1992 et al.). Despite their diversity and
importance in sport, commercial, and subsis-
tence harvest, little research has focused on
these birds. Furthermore, as in the rest of the
world, the grassland habitats that these birds
occupy have been, and continue to be, under
intensive agricultural pressure. For example,
the pampas of Argentina and Uruguay have
been nearly completely converted to row
crops and grazing over the last 150 years (Hall
et al. 1992), and for the past decade have been
subjected to rapidly increasing intensification
(Viglizzo & Roberto 1998).
Despite this continuing land conversion,
and increasingly intense utilization, there is a
conspicuous lack of research into their effects
on biodiversity in grassland ecosystems within
South America. For tinamous however, it is
possible to make inferences based upon the
extensive body of research into the impacts of
land conversion and agriculture on galliforms.
Here I draw from examples on the effects of
agricultural land conversion and intensifica-
tion on grassland bird species in general, and
galliforms in particular, highlighting the major
environmental gradients that impact these
birds, for the purpose of assessing the quality
of grasslands and their associated agro-eco-
systems for tinamous, as well as to direct
future research.
CASES IN THE GALLIFORMES
Due to their importance as gamebirds, the
Galliformes are a well-studied order and sub-
sequently population dynamics are well docu-
mented for many species (e.g., Fuller et al.
2000). Over the last half-century however, as
with many grassland species, galliforms asso-
ciated with grasslands and agro-ecosystems
have exhibited significant population declines
303
TINAMOUS AND AGRICULTURE
across several continents. Important examples
are the Northern Bobwhite (Brennan 1999)
and prairie chickens (Johnsgard 1983, Hous-
ton 2002) in North America, the Helmeted
Guineafowl (Pero & Crowe 1996, Malan &
Benn 1999, Ratcliffe & Crowe 2001) and the
francolins (Little et al. 1995; Jansen et al. 1999,
2000) in South Africa, and the Gray Partridge
in Europe (Potts 1980, 1986).
The decline of populations of these spe-
cies is mostly attributed to changes in the
extent, intensity, and type of land use. Inter-
estingly, several of these species initially
increased their ranges and/or populations as a
function of anthropogenic changes to the
landscape. These changes, however, eventu-
ally passed a threshold where populations
began to decline. The key to making infer-
ences to the tinamous and applying them for
research and management is to understand
the major factors associated with land use that
have both positively and negatively impacted
galliform populations in grasslands and agro-
ecosystems (Johnsgard & Wood 1968, Johns-
gard 1983, Johnson & Knue 1989, Pero &
Crowe 1996, Brennan 1999, Malan & Benn
1999, Ratcliffe & Crowe 2001, Houston
2002).
AGRICULTURAL CHANGES
As discussed by Fuller (2000), the intensifica-
tion in agriculture that has occurred has been
largely due to increased mechanization, the
use of chemical fertilizers, pesticides and her-
bicides, and decreased diversity of crop types.
Mechanization allows for the cultivation of
more area and larger fields, the large-scale
application of fertilizers, pesticides and herbi-
cides, and more frequent tilling or cutting of
hedgerows and field borders.
The use of fertilizers eliminates the need
to leave fields fallow or in pasture, eliminates
the need for manure, thus eliminating the
need for cattle and associated pastures, and
has led to the management of pastures for
silage rather than for hay. The increase in
management for silage allows for higher
stocking levels of livestock since forage can be
subsidized with high quality fodder. High live-
stock densities have been contributing to
decreases in populations of several galliform
species (Jansen et al. 1999, Robbins et al.
2002). Furthermore, mechanization has
allowed for more frequent cutting of these
pastures for silage, leading to increased loss of
nests and young.
The use of petrochemicals, associated
with the decrease in landscape complexity and
diversity, had major implications for popula-
tions of birds in agro-ecosystems due to
impacts on brood survival (Palmer 1995,
Fuller 2000). In particular, the indirect effects
of herbicides and the direct effects of insecti-
cides greatly decrease the quality of agricul-
tural land as brood habitat, and subsequently
brood survival (sensu Potts 1986). Further-
more, the use of fertilizers on silage pastures
leads to a decrease in floral diversity and
structure, and is associated with a decrease in
invertebrate diversity (Fuller 2000).
ASSESSING THE AGRICULTURAL
IMPACTS
The aforementioned factors interact synergis-
tically to decrease the complexity and the
diversity of the landscape and the quality of
habitats within the landscape. Although the
degree to which each factor interacts to affect
a species is species dependent, these factors
can be generalized into several principal gradi-
ents, each consisting of several components.
These gradients are: 1) pesticide and herbicide
use, 2) vegetation structure, 3), intensity of
land use, and 4) area of natural vegetation (i.e.,
not being managed for row crops or silage).
Pesticide and herbicide use includes chem-
ical strength, amount applied, and frequency
of application. Vegetation structure includes
304
THOMPSON
measures of height, density, and species diver-
sity. Intensity of land use is represented by
field size, crop diversity, crop rotation, and
livestock densities and grazing rotations. Area
of natural vegetation not only includes graz-
ing and fallow land, but vegetation and crop
stubble within row crops. The intensity of
land use and area of natural vegetation
together represent a measure of landscape
composition that has been illustrated to be
important for many galliforms (Potts 1986,
Aebischer & Potts 1998, Malan & Benn 1999,
Niemuth 2000).
It is necessary to realize that the impor-
tance that each of these gradients has for a
species will not only depend upon the species
but upon the temporal needs of individuals
and, subsequently, dietary and habitat require-
ments need to be assessed for all stages of a
species life cycle. This is particularly impor-
tant since agro-ecosystems are dynamic envi-
ronments, and subsequently need to be
assessed and measured at regular intervals
throughout the year.
These gradients act synergistically to
impact populations, but it can be hypothe-
sized that there are two general responses that
can be expected based upon the aforemen-
tioned examples, with the magnitude of the
response dependent upon the species (Fig. 1).
The first is where populations initially
increase as a function of cultivation and/or
grazing, when not intensive or extensive;
however, populations begin to decline rapidly
after the combined effects of the gradients
pass a certain magnitude (Fig. 1a). Such popu-
lation responses have been documented for
Helmeted Guineafowls (Pero & Crowe 1996)
and Greater Prairie-Chickens (Tympanuchus
cupido; Johnsgard & Woods 1968, Johnsgard
FIG. 1. Graphical model of the effects of increasing agricultural intensification on grassland Galliformes.
This may also serve as a model for grassland tinamous in South America.
305
TINAMOUS AND AGRICULTURE
1983, Johnson & Knue, 1989, Houston 2002).
The second response is where populations
remain stable despite initial land conversion
and management but, as in the first example,
decline after the combined impacts of the gra-
dients reach a certain threshold (Fig. 1b). This
response has been evident with the popula-
tion declines of the Northern Bobwhite in the
United States, associated with land conversion
in the 19th and early 20th centuries (Brennan
1999), and with the Redwing Francolin (Fran-
colinus levaillantii) stemming from over grazing
(Jansen et al. 1999).
RESEARCH DIRECTIONS
To successfully apply this model to the con-
servation and management of tinamous in
agricultural landscapes there needs to be
quantitatively rigorous population estimation
of species along various intensities of each of
the proposed gradients (sensu Conroy & Car-
roll 2001). This will allow for an assessment
of the impacts of different land use regimes
on populations and provide baseline data to
assess long term population trends.
Such research only yields the effects of
land use; however, and given the small
amount of information on tinamou biology,
research needs to concentrate on understand-
ing the mechanisms that drive population
dynamics by researching the basic biology of
each species throughout the year. Moreover, if
the model of Galliformes as an inference
holds true, there should be an emphasis on
understanding the reproductive biology and
the factors that affect chick survival, since
these appear to be key factors in determining
population size (Potts 1980, 1986, Palmer
1995).
Given the rapid and continued conversion
of grassland systems to agriculture through-
out South America and the intensification of
that agriculture, there looms a growing crisis
for the conservation of biodiversity within
these systems. As pointed out by Jansen et al.
(1999), gallinaceous gamebirds can serve as
excellent indicators of ecosystem health.
Given that tinamous serve as ecological
equivalents to the galliforms, research into the
effects of land use will not only serve to con-
serve and guide management of these species,
but will contribute to conservation of the
increasingly threatened biodiversity associated
with South American grasslands and agro-
ecosystems.
ACKNOWLEDGMENTS
This presentation and the organization and
attendance of the symposium “Ecology and
Conservation Status of the Tinamiformes” at
the VII Neotropical Ornithological Con-
gress, Termas de Puyehue, Chile was partially
made possible through funding from the
American Pheasant and Waterfowl Society
and the Graduate School of the University of
Georgia. This manuscript was improved by
comments from John P. Carroll.
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... All tinamous are relatively poorly studied; however, in austral South American grasslands the tina mous replace the Galliformes and are their ecological equivalent, which allows for inferences to be drawn among the Galliformes and the Tinamiformes in regard to tinamou ecology (Thompson 2004). We used radio telemetry to investigate our theory of ecological equivalence. ...
... The preferences in habitat, size of home ranges, and survival that we observed were consistent with our expectations based upon existing knowledge of tinamou ecology, and the response of Galliformes and other bird species to the intensification of agricultural land use (Thompson 2004). From this study and others (Canavelli et al. 2003, Bellis et al. 2004, Demaría et al. 2002, Fernandez et al. 2003) it is apparent that the intensification of agriculture that has occurred in Argentina has resulted in similar negative ecological effects as observed in other regions. ...
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Full-text available
Changes in the composition and configuration of agricultural landscapes stemming from grassland conver-sion and agricultural intensification have contributed to the global declines of many grassland and shrubland birds. In both North America and Europe there exists a large body of research on the effects of agriculture on populations of terrestrial gamebirds. However, little research exists for these species in Argentina or Latin America in general. In Argentina the most important gamebird species is the spotted tinamou (Nothura mac-ulosa). This species has become increasingly scarce in a significant portion of its range, possibly due to agricultural intensification over the last 15 years. Using radio telemetry, we examined habitat use, movements, and survival of spotted tinamous in 2 landscapes in the province of Buenos Aires, Argentina; one dominated by annual row crops and the other used for annual crops and grazing. During winter, individuals used in order of preference: fallow fields and areas with short herbaceous vegetation, followed by wetlands. Areas in winter wheat and field edges were used least in relation to their availabilty. Although birds generally maintained small home ranges, in some cases changes in cattle density and the structure of row crops caused birds to move considerable distances. Survival mid-winter to early spring was more than double in the mixed landscape s = 0.73, SE = 0.19) compared with the landscape dedicated to row crops s = 0.33, SE = 0.19). Considering how research in other parts of the world has demonstrated the effects of agricultural intensification on terrestrial gamebirds, these results are not unexpected and suggest a precarious future for the conservation of grassland and agroecosystem species in Argentina in light of present agricultural trends.
... Galliformes are an important avian order widely distributed across the continents (del Hoyo et al. 1994). They are seed dispersers, they regulate plant density by eating seeds (Thompson 2004) and they are also strictly connected to humans because they are widely domesticated and hunted for food, plumage and trading (Keane et al. 2005), as well as because of cultural importance (Peters et al. 2016). However, this group of birds is facing increased threats related to overhunting, habitat loss and fragmentation, and human disturbance (McGowan et al. 2012). ...
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The assessment of the conservation status of a species is the first step to prevent local extinction and to plan appropriate, effective and scientifically sound conservation actions, hence knowledge of the distribution, population trends and characteristics of preferred habitat is crucial for the conservation of a species. Galliformes are facing increasing threats related to overhunting, habitat loss and fragmentation, and human disturbance. The Sicilian Rock Partridge (hereafter Rock Partridge) Alectoris graeca whitakeri is a significant conservation unit endemic to Sicily (Italy) classified as Near Threatened by the IUCN due to a decreasing population. Few studies have been conducted on the occurrence and population density of this subspecies. Here, we estimated its population density and identified which habitat factors drive the occurrence of this species on Mt. Etna. We used a combination of sampling methods (species- specific play-back calls, distance sampling, camera-trapping) to collect count and presence/absence data, which were then integrated into a single habitat model (presence vs. absence). We obtained 24 responses from play-back calls (plus 8 individuals observed while performing the play-back calls), 8 sightings from distance sampling, 6 detections from camera-trapping. Probability of occurrence of Rock Partridge on Mt. Etna was positively driven by shrub and meadow vegetation, whereas its occurrence decreased with an increase in both woody areas (coniferous and deciduous) and ele- vation. Population density estimated using play-back call data resulted in 0.80 pairs/km2 (95% CI: 0.17–2.22) over an area of 53.7 km2. The density of Rock Partridge on Mt. Etna appeared to have slightly declined and its distribution under- gone a contraction since the previous survey. Several potential threats to the Rock Partridge in Sicily are currently increasing and should be mitigated to ensure the long-term survival of this unique population on Mt. Etna, as well as in the whole island of Sicily.
... There are few studies on nest success of tinamous and 311 species with similar nesting characteristics (i. e., grassland ground-nesters with similar 312 14 nest materials, incubation periods and nest attendance) in South American grasslands, 313 although some comparisons can be made with grassland galliformes in other areas 314(Thompson 2004). Predation was the principal cause of nest failure, and it occurred at 315 similar rates as in other ground-nesting species (Pitman et al. 2005, Brennan 2010). ...
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https://cdnsciencepub.com/eprint/JS8GEVNTGVJJNMJPMZMM/full _______________________________________________________________________ Grassland degradation and fragmentation produced by land use have globally impacted biodiversity. In the Neotropics, the Pampas Grasslands have been greatly altered by agriculture and the introduction of exotic trees. To evaluate the effects of changing habitat features on native grassland fauna, we studied a breeding population of a ground nesting bird, the Spotted Nothura Nothura maculosa (Temminck, 1985) in a natural grassland under cattle-grazing in central-east Argentina. We estimated daily nest survival rate (DSR) and modeled it as a function of habitat (distance to habitat edges, cattle density and nest concealment) and temporal factors. Of the 80 nests found, 64 (80 %) failed, predation being the principal cause of failure. DSR was 0.874, estimating a cumulative survival of only 6.8 % throughout egg laying and incubation. DSR increased with distance to continuous forests and decreased with nest age. Nests located near forest edges could have increased predation risk because they are potentially exposed to forest dwelling predators in addition to grassland dependent ones. Considering the low success found and the ongoing invasion of exotic trees in the region, we encourage governments to protect large areas of grassland that ensure adequate nest success for tinamous and other ground nesting birds.
... En general, Galliformes como la Perdiz gris (Perdix perdix) en Europa (Kalchreuter 1982, Pain & Pienkowski 1997 y el Faisán (Phasianus colchicus) en Norteamérica (Warner & Etter 1989, Warner et al. 1999 , aves similares a la Perdiz chilena, han sufrido una marcada declinación poblacional por muertes directas e indirectas, debida a la intensifi-cación de la agricultura gracias a la mecanización de las labores. Thompson (2004) considera a los tinamúes que viven en pastizales como los equivalentes ecológicos de los Galliformes y postula que los negativos efectos de la mecanización e intensificación de la agricultura registrados en el hemisferio norte sobre este orden también ocurrirán en los Tinamiformes en el Neotrópico, incluyendo muertes directas por maquinaria. ...
... La Colorada (R. rufescens) es una especie fuertemente asociada a hábitats de pastizales con estructuras complejas, y aunque ésta realmente utiliza hábitats agrícolas, es sensible a la pérdida de pastizales y a pastizales fuertemente pastoreados (Hudson 1892, Narosky y DiGiacomo 1993, Pinheiro y López 1999, Isacch et al. 2003, Isacch et al. 2005 Cardoni 2011, BirdLife International 2013, J.J.Thompson: datos no publicados). Esto es consistente con la relación fuertemente negativa con el aumento de la superficie proporcional de cultivos de cosecha observados en nuestro análisis y la respuesta esperada de especies de tinámidos sensibles a la pérdida de hábitat (Thompson 2004). Del mismo modo, la respuesta negativa del Aguilucho langostero (Buteo swainsoni) al área de cultivos anuales estimada por nuestro modelo, es consistente con la ecología de la especie (Canavelli et al. 2003). ...
... major was included in this study because tinamids are ecologically similar to galliforms, and its size is consistent with the range of the guild (Thompson 2004;Brooks et al. 2004). ...
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Low intensity subsistence agriculture is generally believed to be less damaging to wildlife than intensive farming. As Myanmar is undergoing rapid modernization, subsistence farming may shift to intensive agriculture, resulting in increased threats to species of conservation concern such as the green peafowl Pavo muticus . Here we investigate habitat use of the green peafowl in a low intensity agricultural landscape surrounding a small forest fragment in southern Shan State, Myanmar. The forest belongs to Nan Kone Buddha Monastery and the green peafowl is protected from hunting in the area on the basis of religious beliefs. We established three survey transects with a total length of 3,414 m. During February 2016–January 2017 we conducted surveys twice daily for 4 consecutive days every month, walking all transects in both directions in the mornings and afternoons and recording visual and auditory peafowl encounters. We estimated peafowl density to be 2.63 animals/km ² in the less disturbed western part of the study area and 1.13 animals/km ² in the eastern part, which had higher levels of human disturbance. The peafowl's habitat use was significantly non-random, with forest patches being the most utilized habitat, followed by croplands. Within a 300 m buffer zone around the forest patch, the order of habitat preference was crop > scrub > fallow, with crop significantly preferred over the other two habitats. We conclude that preserved isolated forest blocks adjacent to community-managed agricultural areas are important for green peafowl conservation, and discuss the implications for long-term conservation management of the species.
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I documented agricultural changes during the mid-18 th century until the present in the principal temperate agricultural regions of the world (western Europe, the United States of America, the Republic of South Africa, and austral South America, with a concentration on the Republic of Argentina) from the perspective of the impacts that intensification in agriculture has on wildlife in agroecosystems. Additionally, I produced an analysis and synthesis of the effects of agricultural land use on birds, with an emphasis on the Galliformes. Based upon these analysis, and field research on the spotted tinamou (Nothura maculosa) in agroecosystems in the Pampas of Argentina, I discuss the past, present, and future implications for wildlife conservation and management in agroecosystems in the Pampas and Chaco and Yungas forest of Argentina. In the regions analyzed, agricultural production has become increasingly intensified since the mid-20 th century; typified by increased mechanization, irrigation, agrochemical use, farm consolidation, regional specialization, area of cultivated pastures, and livestock densities. Combined, these reduce the amount, quality, and heterogeneity in habitats across scales from the region to within fields, which the analysis revealed were the factors most influential in determining distribution and abundance of avian species dependent upon these systems. Specifically, the loss of fallow or idle land, woody encroachment, homogeneity in cover types and vegetation structure and composition, indirect effects of pesticides on food availability, and earlier and more frequent mowing were key in explaining reductions in avian diversity and abundance in temperate agroecosystems. For the Galliformes the loss and/or degradation of preferred habitats, during both the breeding and non-breeding seasons, due to changes in agroecosystem management was related to observed decreases in populations and survival. Over-winter mortality increased during extremes in minimum temperature and snow cover, and was exacerbated where sufficient wintering cover was limited. Moreover, increased over-winter mortality was associated with the proximity of woody areas, which facilitates higher predation. The loss of preferred nesting habitat not only decreases the number of nesting individuals, but increases nest loss and mortality of incubating adults through increased predation and losses to agricultural activities. Of particular importance were decreases in the abundance of preferred arthropod prey for foraging chicks due to direct and indirect effects of pesticides, which were responsible for increased chick mortality. Although there exists a large body research into the effects of land use and birds, particularly gamebirds, little research exists for these species in Argentina or Latin America in general. In Argentina the most important gamebird species is the spotted tinamou (Nothura maculosa). This species has become increasingly scarce in a significant portion of its range, possibly due to agricultural intensification over the last 15 years. Using radio telemetry, I examined habitat use, movements, and survival of spotted tinamous in two landscapes in the province of Buenos Aires, Argentina; one dominated by annual row crops and the other used for annual crops and grazing. During winter, individuals used in order of preference: fallow fields and areas with short herbaceous vegetation, followed by wetlands. Areas in winter wheat and field edges were used least in relation to their availability. Although birds generally maintained small home ranges, in some cases changes in cattle density and the structure of row crops caused birds to move considerable distances. Survival mid-winter to early spring was more than double in the mixed landscape (^s = 0.73, SE = 0.19) compared with the landscape dedicated to row crops (^s = 0.33, SE = 0.19). Given the general trends documented for the Galliformes in relation to agricultural intensification, and considering the Tinamiformes as ecological equivalents to the Galliformes in agroecosystems, these results are not unexpected and suggest a precarious future for the conservation of grassland and agroecosystem species in Argentina in light of present agricultural trends. The intensification and expansion of row crop agriculture and grazing in Argentina have negative implications for wildlife as habitat is converted and degraded as witnessed in the spotted tinamou. In the Pampas, the biggest threat for wildlife conservation is the conversion of remnant grassland and residual areas in row crop regions and the expansion of row crops and perennial forage crops into former extensive grazing areas. In northern Argentina the deforestation of Chaco and Yungas forest for soybean cultivation has been extensive and is accelerating, threatening the relatively high biodiversity of these areas. The lack of sufficient funding and infrastructure, and the decentralized nature of wildlife exploitation in Argentina, hinders effective management. Recent success, however, in managing commercially exploited species (parrots) suggest that innovative specie-specific management actions maybe viable.
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ABSTRACT The grasslands of southeastern South America (SESA), comprising one of the most extensive grassland ecosystems in the Neotropics, have been negatively impacted by the development of the livestock industry, arable agriculture, and forestry. SESA grasslands have a rich avifauna that includes 22 globally threatened and near-threatened species, and many other species have suffered local population extinctions and range reductions. In addition to habitat loss and fragmentation, grassland birds in SESA are threatened by improper use of agrochemicals, unfavorable fire management regimes, pollution, and illegal capture and hunting. Studies to date have provided information about the distribution of grassland birds, the threats populations face, and the habitat requirements of some threatened species, but more information is needed concerning dispersal and migration patterns, genetics, and factors that influence habitat use and species survival in both natural and agricultural landscapes. There are few public protected areas in the region (1% of original grasslands), and many populations of threatened grassland birds are found on private lands. Therefore, efforts to preserve grassland habitat must reconcile the interests of land owners and conservationists. Current conservation efforts include establishment of public and private reserves, promotion of agricultural activities that reconcile production with biodiversity conservation, development of multilateral conservation projects across countries, and elaboration of action plans. Measures that result in significant losses to private land owners should include economic compensation, and use of economic incentives to promote agriculture and forestry in native grassland areas should be discouraged, especially in priority areas for grassland birds. Although more studies are needed, some actions, particularly habitat protection and improved management of public and private lands, should be taken immediately to improve the conservation status of grassland birds in SESA. Los pastizales del sureste de Sudamérica (SESA), que conforman uno de los mayores ecosistemas de pastizales en el Neotrópico, han sufrido transformaciones importantes debido al desarrollo de la industria ganadera, la agricultura y la forestación. Los pastizales del SESA tienen una rica avifauna que incluye 22 especies amenazadas o casi amenazadas y muchas otras han sufrido extinciones poblacionales locales y reducciones muy sustanciales de sus rangos de distribución. Además de la pérdida de hábitat y la fragmentación, las aves de pastizal del SESA están amenazadas por el uso inapropiado de agroquímicos, regímenes desfavorables de manejo del fuego, contaminación, captura y caza ilegales. Los estudios al día de hoy han generado información sobre la distribución de aves de pastizal, las amenazas que sus poblaciones enfrentan y de los requerimientos de hábitat de algunas especies amenazadas, pero aun es necesaria más información sobre patrones de dispersión y migración, genética y los factores que afectan los patrones de uso de hábitat y la sobrevivencia de especies en paisajes naturales y agrícolas. Hay muy pocas áreas protegidas públicas en la región (1% de los pastizales originales) y muchas poblaciones de aves de pastizal amenazadas se encuentran en tierras privadas. Por ende, los esfuerzos que buscan preservar características de hábitat similares a las de los pastizales naturales deben reconciliar los intereses de productores y conservacionistas. Los actuales esfuerzos de conservación, incluyen, el establecimiento de reservas privadas y públicas, la promoción de prácticas agrícolas que reconcilien producción y conservación, el desarrollo de proyectos multilaterales de conservación entre varios países, y la elaboración de planes de acción. Las medidas que resultan en pérdidas significativas para los productores privados deberían incluir compensaciones económicas, y el empleo de incentivos económicos para fomentar la agricultura y forestación en pastizales nativos deberían ser desalentado, especialmente en el caso de áreas de prioridad para aves amenazadas. A pesar de que todavía se necesitan mas estudios, algunas medidas, en particular la protección y manejo de hábitat tanto en tierras públicas como privadas deberían aplicarse inmediatamente para mejorar el estado de conservación de las aves de pastizal en el SESA.
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Helmeted guineafowl Numida meleagris populations in KwaZulu-Natal which once provided some of the best gamebird hunting in Africa have declined significantly over the past 15 years. This study investigated, by means of a questionnaire survey, the apparent collapse of guineafowl populations in the KwaZulu-Natal Midlands and Drakensberg regions, and the potential agricultural causes thereof. The number of pesticides used, their toxicity levels, and the proportion of land under cultivation can be used to discriminate significantly between extinct and declining versus stable and increasing guineafowl populations, being higher in the former populations. These results suggest that efficient, intensive farming practices have not only compressed the period in the farming year over which food is available to the guineafowl, but also reduced the suitability of farmlands as wildlife habitat. Remedies are suggested to resuscitate declining populations and optimize their long-term preservation for potential sustainable utilization. Recommended management actions include the judicious use of pesticides and the creation of suitable habitat at the landscape scale.
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A large number of techniques are available for assessing populations of vertebrates. However, application of many of those techniques to Galliformes is hampered by a variety of constraints. These problems are often magnified by poor understanding of the biology of many species of concern, and an absence of valid estimates of abundance and demographic parameters. Researchers interested in developing estimates of Galliformes populations must address a number of key issues before collecting field data, to avoid biases in the resulting population estimates. General guidance exists for the identification of appropriate population estimation techniques, and a dichotomous key has been developed for abundance estimation of other vertebrates, such as mammals. First, we review some of the basic principles of abundance estimation, with the goal of identifying sources of bias, and avoiding these in field surveys. We then develop specific guidelines for Galliformes, and a key to abundance estimation for field researchers. Based on our knowledge of the general biology of Galliformes, the most applicable techniques for estimating abundance are based on variations of distance sampling techniques, mark-resighting techniques, and removal techniques. Use of indices should be considered only when more quantitative analyses are logistically or biologically impossible. However, their use can be made more valuable by employing double sampling or other methods that directly link indices to unbiased estimates of abundance.
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The effects of deciduous fruit orchard farming on the distribution of the southern African endemic Cape francolin, Francolinus capensis, was investigated by comparing the size and placement of the home ranges of six individuals (coveys) in the fruit orchards with those of four individuals (coveys) in an extensive fynbos habitat. The mean daily home range size of Cape francolin was 1.34 ha in the orchards and only 0.23 ha in extensive fynbos. Whereas home ranges were separated, on average, by 96.7 m in the natural habitats, they were highly overlapping and straddled the fynbos patches present within the orchards. Roosting sites in the orchards were all within the fynbos patches and the mean distance moved daily from these patches was 125.3 m. The mean proportion of the day spent outside of the fynbos patches within the orchards was 72.5%. Group sizes were not significantly different between orchards (mean=4.27, SD=1.5, N=15 coveys) and extensive fynbos (mean=4.9, SD=2.5, N=16 coveys) habitats. It is therefore suggested that the placement, size and connectedness of fragmented natural habitats between the orchards determines the distribution of Cape francolin within deciduous fruit farms.
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In western Canada, the Greater Prairie-Chicken (Tympanuchus cupido) has come and gone. Following closely on agricultural settlement, thriving on grain as an alternate food, the "Pinnated Grouse" reached Winnipeg in 1881 and Carberry, Manitoba, in 1886; Indian Head, Saskatchewan, in 1895; and Hanna, Alberta, in 1911. It spread as far northwest as Lac la Biche, Alberta. Once half the land in a given area was broken, this species diminished in numbers, retreating to local areas of thick grass around sloughs and lakes. By the late 1930s almost all were gone. Habitat factors such as fragmentation and separation of grasslands were further accentuated by cattle overgrazing, burning, and drought, and then by hybridization of surviving, isolated birds. By accessing records for the prairie provinces from nine unpublished or not-readily-available sources (unavoidably skewed by a preponderance of Saskatchewan records), I offer documentation of increases and decreases, as well as an assessment of the species' status in northeastern Montana and northwestern Ontario. I have also catalogued 131 Northern Great Plains egg sets from 36 North American oology collections. Together this material allows a more complete assessment than has been possible previously.
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This chapter focuses on the causes of the decline of the grey partridge and explains the associated increase of the red-legged partridge in some areas. It is intended to develop an ecological rationale for the practical conservation and exploitation of these birds, bearing in mind current trends in agriculture. Computer simulation techniques have been extensively used. Most attention is directed to the grey partridge, and the future of this as a quarry species on farmland is seriously threatened by the inexorable increase in the use of pesticides and by the removal of hedges and similar nesting cover. Comparative studies on the red-legged partridge have been included because they support much of the argument concerning population processes. By way of deterministic population simulation models, density dependent prebreeding dispersal could have evolved in partridges as a way of reducing nest predation. Spacing is considered as a means of increasing productivity rather than as a means of limiting breeding density.
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Greater prairie-chickens (Tympanuchus cupido pinnatus) have declined dramatically across their range because of habitat loss, primarily agricultural development. In Wisconsin, most prairie-chicken populations are found in grassland reserves managed primarily for prairie-chickens. However, a few remnant populations persist in an agricultural landscape with little or no management for prairie-chickens. I compared land use within 2.4 km of 29 prairie-chicken leks and 25 random points in an agricultural landscape to determine habitat associated with presence of prairie-chickens in central Wisconsin. Areas around leks had higher proportions of grasslands, wetlands, and shrubs than around random points, and lower proportions of forests, row crops, and hay fields. Differences between leks and random points varied with scale of sampling. Leks were unevenly distributed in the landscape, with mean distance to nearest lek shorter for leks than random points (P < 0.001). Leks were positively correlated with proportion of grass, shrub, and pasture, and negatively correlated with distance to nearest lek. Number of displaying males was negatively correlated with proportion of row crops and positively correlated with proportion of grassland in the landscape. Correlates of number of males also varied with scale of sampling.