Response of the endemic Long-tailed Meadowlark (Sturnella loyca obscura) to grazing exclusion in herbivore-dependent upland grasslands of Argentina
Laura M. Bellis A B C and Nadia Muriel BA Instituto de Diversidad y Ecología Animal, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba (IDEA-CONICET-UNC), Vélez Sarsfield 299, 5000, Córdoba, Argentina.
B Cátedra de Ecología, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina. Vélez Sarsfield 299, 5000, Córdoba, Argentina.
C Corresponding author. Email: lbellis@com.uncor.edu
Emu 115(2) 176-184 https://doi.org/10.1071/MU14030
Submitted: 20 July 2013 Accepted: 23 October 2014 Published: 16 April 2015
Abstract
In grassland ecosystems livestock grazing is one of the main activities that modify habitat and which can lead to positive or negative effects on birds. In the Sierras Grandes of Córdoba, Argentina, livestock grazing began early in the 17th century, causing severe soil erosion. To restore the grasslands, livestock were excluded from a large area in 1997. However, the impact of grazing exclusion on endemic birds is not clear. We evaluated the effect of grazing exclusion on density and habitat attributes of populations of Long-tailed Meadowlarks (Sturnella loyca obscura). The highest density was recorded in ungrazed sites. Fitted models explained up to 75% of the variability in density of Long-tailed Meadowlarks. Litter depth, percentage of bare soil (with positive effects), soil compaction (estimated as impedance) and percentage of moss cover (with negative effects) were the most important variables explaining the variation in the estimated density of birds. We concluded that 11 years of grazing exclusion favoured Meadowlark populations, providing increased availability of resources, mainly those related to soil quality. Hence, we recommend promoting alternative management practices, such as reintroduction of large native herbivores where possible and livestock grazing at reduced stocking rates, to counterbalance the cost of soil loss and the benefit that large herbivores provide to the system.
Additional keywords: Córdoba, density, ground-feeding birds, livestock effects, mountains.
References
Albanesi, S., Dardanelli, S., and Bellis, L. M. (2014). Effects of fire disturbance on bird communities and species of mountain serrano forest of Central Argentina. Journal of Forest Research 19, 105–114.| Effects of fire disturbance on bird communities and species of mountain serrano forest of Central Argentina.Crossref | GoogleScholarGoogle Scholar |
Anderson, J. R., and Merritt, R. W. (1977). The impact of foraging Meadowlarks, Sturnella neglecta, on degradation of cattle dung pads. Journal of Applied Ecology 14, 355–362.
| The impact of foraging Meadowlarks, Sturnella neglecta, on degradation of cattle dung pads.Crossref | GoogleScholarGoogle Scholar |
Askins, R. A., Chavez-Ramírez, F., Dale, B. C., Haas, C. A., Herkert, J. R., Knopf, F., and Vickery, P. D. (2007). Conservation of grassland birds in North America: understanding ecological processes in different regions. Ornithological Monographs 64, 2–46.
Azpiroz, A. B., Isacch, J. P., Dias, R. A., Di Giacomo, A. S., Suertegaray Fontana, C., and Morales Palarea, C. (2012). Ecology and conservation of grassland birds in southeastern South America: a review. Journal of Field Ornithology 83, 217–246.
| Ecology and conservation of grassland birds in southeastern South America: a review.Crossref | GoogleScholarGoogle Scholar |
Baker, D. L., and Guthery, F. S. (1990). Effects of continuous grazing on habitat and density of ground-foraging birds in south Texas. Journal of Range Management 43, 2–5.
| Effects of continuous grazing on habitat and density of ground-foraging birds in south Texas.Crossref | GoogleScholarGoogle Scholar |
Bellis, L. M., Rivera, L., Politi, N., Martin, E., Perasso, M. L., Cornell, F., and Renison, D. (2009). Latitudinal patterns of bird richness, diversity and abundance in Polylepis australis mountain forest of Argentina. Bird Conservation International 19, 265–276.
| Latitudinal patterns of bird richness, diversity and abundance in Polylepis australis mountain forest of Argentina.Crossref | GoogleScholarGoogle Scholar |
Bibby, C. J., Burgess, N. D., Hill, D. A., and Mustoe, S. (2000). ‘Bird Census Techniques.’ (Academic Press: London.)
Blomqvist, M. M., Olff, H., Blaauw, M. B., Bongers, T., and Vanderputten, W. H. (2000). Interactions between above- and belowground biota: importance for small-scale vegetation mosaics in a grassland ecosystem. Oikos 90, 582–598.
| Interactions between above- and belowground biota: importance for small-scale vegetation mosaics in a grassland ecosystem.Crossref | GoogleScholarGoogle Scholar |
Bock, C. E. (1999). ‘Birds and Bovines: Effects of Livestock Grazing on Birds in the West.’ (Public Lands Ranching Organization Press: Boulder, CO.)
Bollinger, E. K. (1995). Successional changes and habitat selection in hayfield bird communities. Auk 112, 720–730.
Buckland, S. T., Anderson, D. R., Burnham, K. P., Laake, J. L., Borchers, D. L., and Thomas, L. (2001). ‘Introduction to Distance Sampling: Estimating Abundance of Biological Populations.’ (Oxford University Press: New York.)
Cabido, M., Funes, G., Pucheta, E., Vendramini, F., and Díaz, S. (1998). A chorological analysis of the mountains from central Argentina: is all what we call Sierra Chaco really Chaco? Contribution to the study of the flora and vegetation of the Chaco. XII. Candollea 53, 321–331.
Cagnolo, L., Molina, S. I., and Valladares, G. R. (2002). Diversity and guild structure of insect assemblages under grazing and exclusion regimes in a montane grassland from Central Argentina. Biodiversity and Conservation 11, 407–420.
| Diversity and guild structure of insect assemblages under grazing and exclusion regimes in a montane grassland from Central Argentina.Crossref | GoogleScholarGoogle Scholar |
Cingolani, A. M., Cabido, M. R., Renison, D., and Solís Neffa, V. (2003). Combined effects of environment and grazing on vegetation structure in Argentine granite grasslands. Journal of Vegetation Science 14, 223–232.
| Combined effects of environment and grazing on vegetation structure in Argentine granite grasslands.Crossref | GoogleScholarGoogle Scholar |
Cingolani, A. M., Renison, D., Zak, M., and Cabido, M. (2004). Mapping vegetation in a heterogeneous mountain rangeland using Landsat data: an alternative method to define and classify land-cover units. Remote Sensing of Environment 92, 84–97.
| Mapping vegetation in a heterogeneous mountain rangeland using Landsat data: an alternative method to define and classify land-cover units.Crossref | GoogleScholarGoogle Scholar |
Cingolani, A. M., Noy-Meir, I., Renison, D., and Cabido, M. (2008a). La ganadería extensiva, ¿es compatible con la conservación de la biodiversidad y de los suelos? Ecología Austral 18, 253–271.
Cingolani, A. M., Renison, D., Tecco, P., Gurvich, D., and Cabido, M. (2008b). Predicting cover types in a mountain range with long evolutionary grazing history: a GIS approach. Journal of Biogeography 35, 538–551.
| Predicting cover types in a mountain range with long evolutionary grazing history: a GIS approach.Crossref | GoogleScholarGoogle Scholar |
Cingolani, A. M., Vaieretti, M. V., Giorigis, M. A., La Torre, N., Whitworth-Hulse, J. I., and Renison, D. (2013). Can livestock and fires convert the sub-tropical mountain rangelands of central Argentina into a rocky desert? Rangeland Journal 35, 285–297.
| Can livestock and fires convert the sub-tropical mountain rangelands of central Argentina into a rocky desert?Crossref | GoogleScholarGoogle Scholar |
Davies, S. K (2005). Nest-site selection patterns and the influence of vegetation on nest survival of mixed-grass prairie passerines The Condor 107, 605–616.
Dechant, J. A., Sondreal, M. L., Johnson, D. H., Igl, L. D., Goldade, C. M., Zimmerman, A. L., and Euliss, B. R. (2002). Effects of management practices on grassland birds: Western Meadowlark. USGS Northern Prairie Wildlife Research Center, Jamestown, ND. Available at: http://digitalcommons.unl.edu/usgsnpwrc/116 (Verified 3 March 2015).
Dennis, P., Skartveit, J., McCracken, D. I., Pakeman, R. J., Beaton, K., Kunaver, A., and Evans, D. M. (2008). The effects of livestock grazing on foliar arthropods associated with bird diet in upland grasslands of Scotland. Journal of Applied Ecology 45, 279–287.
| The effects of livestock grazing on foliar arthropods associated with bird diet in upland grasslands of Scotland.Crossref | GoogleScholarGoogle Scholar |
Devereux, C. L., Whittingham, M. J., Fernández-Juricic, E., Vickery, J. A., and Krebs, J. R. (2005). Predator detection and avoidance by starlings under different scenarios of predation risk. Behavioral Ecology 17, 303–309.
| Predator detection and avoidance by starlings under different scenarios of predation risk.Crossref | GoogleScholarGoogle Scholar |
Di Rienzo, J. A., Casanoves, F., Balzarini, M. G., Gonzalez, L., Tablada, M., and Robledo, C. W. (2013). InfoStat versión 2013. Grupo InfoStat, FCA, Universidad Nacional de Córdoba, Argentina. Available at: http://www.infostat.com.ar
Díaz, S., Acosta, A., and Cabido, M. (1994). Community structure in montane grasslands of central Argentina in relation to land use. Journal of Vegetation Science 5, 483–488.
| Community structure in montane grasslands of central Argentina in relation to land use.Crossref | GoogleScholarGoogle Scholar |
Donald, P. F., Sanderson, F. J., Burfield, I. J., and Van Bommel, F. P. J. (2006). Further evidence of continent-wide impacts of agricultural intensification on European farmland birds 1990–2000. Agriculture, Ecosystems & Environment 116, 189–196.
| Further evidence of continent-wide impacts of agricultural intensification on European farmland birds 1990–2000.Crossref | GoogleScholarGoogle Scholar |
Dormann, C. F., McPherson, J. M., Araujo, M. B., Bivand, R., Bolliger, J., Carl, G., Davies, R. G., Hirzel, A., Jetz, W., Kissling, W. D., Kühn, I., Ohlemüller, R., Peres-Neto, P. R., Reineking, B., Schröder, B., Schurr, F. M., and Wilson, R. (2007). Methods to account for spatial autocorrelation in the analysis of species distributional data: a review. Ecography 30, 609–628.
| Methods to account for spatial autocorrelation in the analysis of species distributional data: a review.Crossref | GoogleScholarGoogle Scholar |
Fernández, G. J., Posse, G., Ferreti, V., and Gabelli, F. M. (2004). Bird-habitat relationship for the declining Pampas Meadowlark populations in the southern Pampas grasslands. Biological Conservation 115, 139–148.
| Bird-habitat relationship for the declining Pampas Meadowlark populations in the southern Pampas grasslands.Crossref | GoogleScholarGoogle Scholar |
Fjeldsa, J., and Kessler, M. (1996). ‘Conserving the Biological Diversity of Polylepis Woodlands of the Highland of Peru and Bolivia. A Contribution to Sustainable Natural Resource Management in the Andes.’ (Nordic Foundation for Development and Ecology (NORDECO): Copenhagen, Denmark.)
Flores, C. E., Cingolani, A. M., von Muller, A. R., and Barri, F. R. (2012). Habitat selection by reintroduced Guanacos (Lama guanicoe) in a heterogeneous mountain rangeland of central Argentina. Rangeland Journal 34, 439–445.
| Habitat selection by reintroduced Guanacos (Lama guanicoe) in a heterogeneous mountain rangeland of central Argentina.Crossref | GoogleScholarGoogle Scholar |
Fondell, T. F., and Ball, I. J. (2004). Density and success of bird nests relative to grazing on western Montana grasslands. Biological Conservation 117, 203–213.
| Density and success of bird nests relative to grazing on western Montana grasslands.Crossref | GoogleScholarGoogle Scholar |
Gabelli, F. M., Fernández, G. J., Ferretti, V., Posse, G., Coconier, E., Gavieiro, H. J., Llambías, P. E., Peláez, P. I., Vallés, M. L., and Tubaro, P. L. (2004). Range contraction of the Pampas Meadowlark Sturnella defilippii in the southern pampas grasslands of Argentina. Oryx 38, 1–7.
| Range contraction of the Pampas Meadowlark Sturnella defilippii in the southern pampas grasslands of Argentina.Crossref | GoogleScholarGoogle Scholar |
García, C., Renison, D., Cingolani, A. M., and Fernández-Juricic, E. (2008). Avifaunal changes as a consequence of large-scale livestock exclusion in the mountains of central Argentina. Journal of Applied Ecology 45, 351–360.
| Avifaunal changes as a consequence of large-scale livestock exclusion in the mountains of central Argentina.Crossref | GoogleScholarGoogle Scholar |
Gardner, S. M., Cabido, M., Valladares, G. R., and Díaz, S. (1995). The influence of habitat structure on arthropod diversity in Argentine semi-arid Chaco forest. Journal of Vegetation Science 6, 349–356.
| The influence of habitat structure on arthropod diversity in Argentine semi-arid Chaco forest.Crossref | GoogleScholarGoogle Scholar |
Gilroy, J. J., Anderson, G. Q. A., Vickery, J. A., Grice, P. V., Watts, P. N., Bray, I., and Sutherland, W. J. (2008). Could soil degradation contribute to farmland bird declines? Links between soil penetrability and the abundance of Yellow Wagtails in UK arable fields. Biological Conservation 141, 3116–3126.
| Could soil degradation contribute to farmland bird declines? Links between soil penetrability and the abundance of Yellow Wagtails in UK arable fields.Crossref | GoogleScholarGoogle Scholar |
Hays, R. L., Summers, C., and Seitz, W. (1981). Estimating wildlife habitat variables. Report FWS/OBS-81/47, Biological Services Program, Fish and Wildlife Service, US Department of the Interior, Washington, DC. Available at: http://tidalmarshmonitoring.org/pdf/Hays1981_EstimatingWildlifeHabitatVariables.pdf [Verified 23 February 2015].
Hull, S. D. (2000). Effects of management practices on grassland birds: Eastern Meadowlark. Northern Prairie Wildlife Research Center, Jamestown, ND. Available at: http://www.npwrc.usgs.gov/resource/literatr/grasbird/eame/eame.htm [Verified 23 February 2015].
Hutto, R. L. (1985). Habitat selection by non-breeding, migratory land birds. In ‘Habitat Selection in Birds’. (Ed. M. L. Cody.) pp. 455–476. (Academic Press: Orlando, FL.)
Isaaks, E. H., and Srivastava, R. M. (1989). ‘An Introduction to Applied Geostatistics.’ (Oxford University Press: New York.)
Isacch, J. P., and Martínez, M. M. (2001). Estacionalidad y relaciones con la estructura del hábitat de la comunidad de aves de pastizales de paja colorada (Paspalum quadrifarium) manejados con fuego en la provincia de Buenos Aires, Argentina. Ornitologia Neotropical 12, 345–354.
Knapp, A. K., Blair, J. M., Briggs, J. M., Collins, S. L., Hartnett, D. C., Johnson, L. C., and Gene-Towne, E. (1999). The keystone role of Bison in North American tallgrass prairie. Bioscience 49, 39–50.
| The keystone role of Bison in North American tallgrass prairie.Crossref | GoogleScholarGoogle Scholar |
Lal, R. (2001). Soil degradation by erosion. Land Degradation & Development 12, 519–539.
| Soil degradation by erosion.Crossref | GoogleScholarGoogle Scholar |
Landi, M. A., and Renison, D. (2010). Forestación con Polylepis australis en suelos erosionados de las Sierras Grandes de Córdoba: evaluación del uso de terrazas y vegetación nodriza. Ecología Austral 20, 47–55.
Lanyon, W. E. (1995). Eastern Meadowlark (Sturnella magna). In ‘The Birds of North America’. (Eds A. Poole and F. Gill.) No. 160. (The Academy of Natural Sciences and The American Ornithologists’ Union: , Philadelphia, PA, and Washington, DC.)
Mac Nally, R. (1996). Hierarchical partitioning as an interpretative tool in multivariate inference. Australian Journal of Ecology 21, 224–228.
| Hierarchical partitioning as an interpretative tool in multivariate inference.Crossref | GoogleScholarGoogle Scholar |
Mac Nally, R. (2002). Multiple regression and inference in ecology and conservation biology: further comments on identifying important predictor variables. Biodiversity and Conservation 11, 1397–1401.
| Multiple regression and inference in ecology and conservation biology: further comments on identifying important predictor variables.Crossref | GoogleScholarGoogle Scholar |
Macchi, L., and Grau, H. R. (2012). Piospheres in the dry Chaco. Contrasting effects of livestock puestos on forest vegetation and bird communities. Journal of Arid Environments 87, 176–187.
| Piospheres in the dry Chaco. Contrasting effects of livestock puestos on forest vegetation and bird communities.Crossref | GoogleScholarGoogle Scholar |
Marone, L., Lopez de Casenave, J., and Cueto, V. R. (1997). Patterns of habitat selection by wintering and breeding granivorous birds in the central Monte Desert, Argentina. Revista Chilena de Historia Natural (Valparaiso, Chile) 70, 73–81.
Miatello, R., Baldo, J., Ordano, M., Rosacher, C., and Biancucci, L. (1999). ‘Avifauna del Parque Nacional del Condorito y Reserva Hídrica Provincial de Achala, Córdoba, Argentina. Una lista comentada.’ (Secretaría de Agricultura, Ganadería y Recursos Renovables: Córdoba, Argentina.)
Milchunas, D. G., and Noy-Meir, I. (2002). Grazing refuges, external avoidance of herbivory and plant diversity. Oikos 99, 113–130.
| Grazing refuges, external avoidance of herbivory and plant diversity.Crossref | GoogleScholarGoogle Scholar |
Milsom, T. P., Langton, S. D., Parkin, W. K., Peel, S., Bishop, J. D., Hart, J. D., and Moore, N. P. (2000). Habitat models of bird species’ distribution: an aid to the management of coastal grazing marshes. Journal of Applied Ecology 37, 706–727.
| Habitat models of bird species’ distribution: an aid to the management of coastal grazing marshes.Crossref | GoogleScholarGoogle Scholar |
Molina, S. I., Valladares, G. R., Gardner, S., and Cabido, M. (1999). The effects of logging and grazing on the insect community associated with a semi-arid Chaco forest in central Argentina. Journal of Arid Environments 42, 29–42.
| The effects of logging and grazing on the insect community associated with a semi-arid Chaco forest in central Argentina.Crossref | GoogleScholarGoogle Scholar |
Nack, J. M., and Ribic, C. A. (2005). Apparent predation by cattle at grassland bird nests. Wilson Bulletin 117, 56–62.
| Apparent predation by cattle at grassland bird nests.Crossref | GoogleScholarGoogle Scholar |
Nishida, T., and Chen, D. G. (2004). Incorporating spatial autocorrelation into the general linear model with an application to the Yellowfin Tuna (Thunnus albacares) longline CPUE data. Fisheries Research 70, 265–274.
| Incorporating spatial autocorrelation into the general linear model with an application to the Yellowfin Tuna (Thunnus albacares) longline CPUE data.Crossref | GoogleScholarGoogle Scholar |
Nores, M., and Yzurieta, D. (1983). Especiación en las Sierras Pampeanas de Córdoba y San Luis (Argentina), con descripción de siete nuevas subespecies de aves. El Hornero , 88–102.
Ogada, D. L., Gaad, M. E., Ostfeld, R. S., Young, T. P., and Keesing, F. (2008). Impacts of large herbivorous mammals on bird diversity and abundance in an African savanna. Oecologia 156, 387–397.
| Impacts of large herbivorous mammals on bird diversity and abundance in an African savanna.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1cnltVymsw%3D%3D&md5=b0cb49c360c4b36ed40144d1a929433fCAS | 18288493PubMed |
Pimentel, D., Harvey, C., Resosudarmo, P., Sinclair, K., Kurz, D., McNair, M., Crist, S., Sphpritz, L., Fitton, L., Saffouri, R., and Blair, R. (1995). Environmental and economic costs of soil erosion and conservation benefits. Science 267, 1117–1123.
| Environmental and economic costs of soil erosion and conservation benefits.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXktVKjsL4%3D&md5=b3435a0dc0366e94f5c653e4714b924dCAS | 17789193PubMed |
Pucheta, E., and Cabido, M. (1992). Comunidades de pastizales serranos del centro de Argentina y su relación con el uso pastoril. Phytocoenologia 21, 333–346.
| Comunidades de pastizales serranos del centro de Argentina y su relación con el uso pastoril.Crossref | GoogleScholarGoogle Scholar |
Pucheta, E., Cabido, M., and Díaz, S. (1997). Modelos de estados y transiciones para los pastizales de altura de las sierras de Córdoba, Argentina. Ecotrópicos 10, 151–160.
Pucheta, E., Cabido, M., Díaz, S., and Funes, G. (1998). Floristic composition, biomass, and aboveground net plant production in grazed and protected sites in a mountain of central Argentina. Acta Oecologica 19, 97–105.
| Floristic composition, biomass, and aboveground net plant production in grazed and protected sites in a mountain of central Argentina.Crossref | GoogleScholarGoogle Scholar |
Quinn, G., and Keough, M. (2008). ‘Experimental Design and Data Analysis for Biologists.’ (Cambridge University Press: New York.)
R Core Team (2014). R: a language and environment for statistical computing (version 3.1.0). R Foundation for Statistical Computing, Vienna, Austria. Available at: http://www.Rproject.org [Verified 11 March 2015].
Rahmig, C. R., Jensen, W. E., and With, K. A. (2009). Grassland bird responses to land management in the largest remaining tallgrass prairie. Conservation Biology 23, 420–432.
| Grassland bird responses to land management in the largest remaining tallgrass prairie.Crossref | GoogleScholarGoogle Scholar |
Ralph, C. J., Geupel, G. R., Pyle, P., Martin, T. E., and DeSante, D. F. (1993). Handbook of field methods for monitoring landbirds. General Technical Report PSW-GTR-144-www, Pacific Southwest Research Station, Forest Service, US Department of Agriculture, Albany, CA.
Renison, D., Hensen, I., Suárez, R., Cingolani, A. M., Marcora, P., and Giorgis, M. A. (2010). Soil conservation in Polylepis mountain forests of central Argentina: is livestock reducing our natural capital? Austral Ecology 35, 435–443.
| Soil conservation in Polylepis mountain forests of central Argentina: is livestock reducing our natural capital?Crossref | GoogleScholarGoogle Scholar |
Rotenberry, J. T., and Wiens, J. A. (1980). Habitat structure, patchiness, and avian communities in North American steppe vegetation: a multivariate analysis. Ecology 61, 1228–1250.
| Habitat structure, patchiness, and avian communities in North American steppe vegetation: a multivariate analysis.Crossref | GoogleScholarGoogle Scholar |
Smythe, L., and Haukos, D. (2010). Response of grassland birds in sand shinnery oak communities restored using tebuthiuron and grazing in eastern New Mexico. Restoration Ecology 18, 215–223.
| Response of grassland birds in sand shinnery oak communities restored using tebuthiuron and grazing in eastern New Mexico.Crossref | GoogleScholarGoogle Scholar |
Söderström, B., Pärt, T., and Linnarsson, E. (2001). Grazing effects on between-year variations of farmland bird communities. Ecological Applications 11, 1141–1150.
| Grazing effects on between-year variations of farmland bird communities.Crossref | GoogleScholarGoogle Scholar |
Stattersfield, A. J., Crosby, M. J., Long, A. J., and Wege, D. C. (1998). ‘Endemic Bird Areas of the World. Priorities for Biodiversity Conservation.’ BirdLife Conservation Series 7. (BirdLife International: Cambridge, UK.)
Temple, S. A., Fevold, B. M., Paine, L. K., Undersander, D. J., and Sample, D. W. (1999). Nesting birds and grazing cattle: accommodating both on Midwestern pastures. Studies in Avian Biology 19, 196–202.
Thomas, L., Buckland, S. T., Burnham, K. P., Anderson, D. R., Laake, J. L., Borchers, D. L., and Strindberg, S. (2002). Distance sampling. In ‘Encyclopedia of Environmetrics’. (Eds A. H. ElShaarawi and W. W. Piegorschs.) pp. 544–552. (John Wiley & Sons: Chichester, UK.)
Trimble, S. W., and Mendel, A. C. (1995). The cow as a geomorphic agent – a critical review. Geomorphology 13, 233–253.
| The cow as a geomorphic agent – a critical review.Crossref | GoogleScholarGoogle Scholar |
Tubaro, P. L., and Gabelli, F. M. (1999). The decline of the Pampas Meadowlark: difficulties of applying the IUCN criteria to Neotropical grassland birds. Studies in Avian Biology 19, 250–257.
Van Horne, B. (1983). Density as a misleading indicator of habitat quality. Journal of Wildlife Management 47, 898–901.
Vargas, O., Premauer, J., and Cárdenas, C. (2002). Efecto del pastoreo sobre la estructura de la vegetación en un páramo húmedo de Colombia. Ecotrópicos 15, 35–50.
Vickery, P. D., Hunter, M. L., and Wells, J. W. (1992). Is density an indicator of breeding success? Auk 109, 706–710.
| Is density an indicator of breeding success?Crossref | GoogleScholarGoogle Scholar |
Vickery, P. D., Casañas, H. E., and Di Giacomo, A. (2003). Effects of altitude on the distribution of Nearctic and resident grassland birds in Cordoba province, Argentina. Journal of Field Ornithology 74, 172–178.
| Effects of altitude on the distribution of Nearctic and resident grassland birds in Cordoba province, Argentina.Crossref | GoogleScholarGoogle Scholar |
Whitmore, R. C. (1981) Applied aspects of choosing variables in studies of bird habitats. In ‘The Use of Multivariate Statistics in Studies of Wildlife Habitat’. General Technical Report RM-87. (Ed. D. E. Capen.) pp. 38–41. (Forest Service, US Department of Agriculture: Burlington, Vermont.)
Whittingham, M. J., and Evans, K. L. (2004). The effects of habitat structure on predation risk of birds in agricultural landscapes. Ibis 146, 210–220.
| The effects of habitat structure on predation risk of birds in agricultural landscapes.Crossref | GoogleScholarGoogle Scholar |
Whittingham, M. J., Stephens, P. A., Bradbury, R. B., and Freckleton, R. P. (2006a). Why do we still use stepwise modelling in ecology and behaviour? Journal of Animal Ecology 75, 1182–1189.
| Why do we still use stepwise modelling in ecology and behaviour?Crossref | GoogleScholarGoogle Scholar | 16922854PubMed |
Whittingham, M. J., Devereux, C. L., Evans, A. D., and Bradbury, R. B. (2006b). Altering perceived predation risk and food availability: management prescriptions to benefit farmland birds on stubble fields. Journal of Applied Ecology 43, 640–650.
| Altering perceived predation risk and food availability: management prescriptions to benefit farmland birds on stubble fields.Crossref | GoogleScholarGoogle Scholar |
Wilson, A. M., Fuller, R. J., Day, C., and Smith, G. (2005). Nightingales Luscinia megarhynchos in scrub habitats in the southern fens of East Anglia, England: associations with soil type and vegetation structure. Ibis 147, 498–511.
| Nightingales Luscinia megarhynchos in scrub habitats in the southern fens of East Anglia, England: associations with soil type and vegetation structure.Crossref | GoogleScholarGoogle Scholar |
Yates, C. J., Norton, D. A., and Hobbs, R. (2000). Grazing effects on plant cover, soil and microclimate in fragmented woodlands in south-western Australia: implications for restoration. Austral Ecology 25, 36–47.
| Grazing effects on plant cover, soil and microclimate in fragmented woodlands in south-western Australia: implications for restoration.Crossref | GoogleScholarGoogle Scholar |