scholarly journals The importance of grazing regime in the provision of breeding habitat for grassland birds: The case of the endangered little bustard (Tetrax tetrax)

2012 ◽  
Vol 20 (4) ◽  
pp. 211-218 ◽  
Author(s):  
Nuno Faria ◽  
João E. Rabaça ◽  
Manuel B. Morales
Keyword(s):  
Grassland Birds ◽  
Breeding Habitat ◽  
Tetrax Tetrax

Population productivity and late breeding habitat selection by the threatened Little Bustard: the importance of grassland management

2017 ◽  
Vol 28 (4) ◽  
pp. 521-533 ◽  
Author(s):  
NUNO FARIA ◽  
MANUEL B. MORALES
Keyword(s):  
Habitat Selection ◽  
Species Conservation ◽  
Grassland Management ◽  
Breeding Habitat ◽  
Breeding Period ◽  
Tetrax Tetrax ◽  
Species Population ◽  
Suitable Habitats ◽  
Stocking Rates ◽  
The Relationship

SummaryWe investigated population productivity and habitat selection of the Little BustardTetrax tetraxin the late breeding period, in grassland-dominated landscapes of south-west Iberia. Specifically, our goals were to investigate how these parameters are influenced by the management of (1) grazing and (2) hay production. We conducted bird counts from 22 June to 4 July (2012 to 2016) using low speed 4x4 car surveys. The relationship between the density of the species, population productivity and farm management (grazing and haying) was evaluated using Generalized Linear Mixed Models and Kruskal-Wallis tests. Male and female densities were significantly higher in short vegetation compared to all other types of vegetation considered, but population productivity was similar in short and medium vegetation. Hay stubbles were found to be unattractive for the species. The availability of suitable habitats depends on the timing of grazing, notably of seasonal (spring) grazing. Species density was higher in fields ungrazed during winter and with moderate to high stocking rates in spring (around 0.8 LU/ha or higher), depending, at least for males and females, on each year’s weather characteristics. We conclude that low to moderate stocking rates during winter and spring are essential to ensure successful breeding and thus population persistence. Current levels of haying in our study area are detrimental for the species’ conservation.

scholarly journals Changes in grassland management and linear infrastructures associated to the decline of an endangered bird population

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ana Teresa Marques ◽  
Francisco Moreira ◽  
Rita Alcazar ◽  
Ana Delgado ◽  
Carlos Godinho ◽  
...  
Keyword(s):  
Grassland Birds ◽  
Grassland Management ◽  
Power Lines ◽  
Spatial And Temporal Variation ◽  
Habitat Availability ◽  
Population Declines ◽  
Tetrax Tetrax ◽  
Species Population ◽  
Linear Infrastructures

Abstract European grassland birds are experiencing major population declines, mainly due to changes in farmland management. We analyzed the role of habitat availability, grazing management and linear infrastructures (roads and power lines) in explaining spatial and temporal variation in the population density of little bustards (Tetrax tetrax) in Portugal, during a decade in which the species population size halved. We used data from 51 areas (totaling ca. 1,50,000 ha) that were sampled in two different periods (2003–2006 and 2016). In 2003–2006, when the species occurred at high densities, habitat availability was the only factor affecting spatial variation in bustard density. In the 2016 survey, variation in density was explained by habitat availability and livestock management, with reduced bird numbers in areas with higher proportions of cattle. Population declines across the study period were steeper in areas that initially held higher densities of bustards and in areas with a higher proportion of cattle in the total stocking rate. Areas with higher densities of power lines also registered greater density declines, probably due to avoidance behavior and to increased mortality. Overall, our results show little bustards are currently lacking high quality grassland habitat, whose persistence depends on extensive grazing regimes and low linear infrastructure densities.

scholarly journals Reproductive Success of Chestnut-Collared Longspurs in Native and Exotic Grassland

The Condor ◽  
2005 ◽  
Vol 107 (2) ◽  
pp. 363-374 ◽  
Author(s):  
John D. Lloyd ◽  
Thomas E. Martin
Keyword(s):  
Survival Rate ◽  
Reproductive Success ◽  
Nest Survival ◽  
Grassland Birds ◽  
Egg Laying ◽  
Breeding Habitat ◽  
Agropyron Cristatum ◽  
Population Declines ◽  
Grassland Bird ◽  
Native Prairie

AbstractHabitat loss and fragmentation have been identified as important factors in the decline of grassland bird populations. However, population declines are apparent even in prairie ecosystems that remain relatively intact suggesting that additional factors are involved. The degradation of breeding habitat may be one such factor, but few studies have examined habitat-specific demography of grassland birds, and thus little is known of how changes in breeding habitat may be related to population declines. We addressed this question by comparing reproductive success of Chestnut-collared Longspurs (Calcarius ornatus) in patches of native prairie and in monocultures of crested wheatgrass (Agropyron cristatum), a grass introduced from Asia. Using recently developed methods for estimating nest survival rate, we found that, independent of habitat type, daily nest survival generally declined from egg laying to fledging. We also found a positive effect of clutch size on nest survival rate, which we interpreted as evidence for individual heterogeneity in nest survival. Finally, we found that the odds of a nest surviving a given day were 17% lower in the exotic habitat, and that nestlings grew more slowly, and had a smaller final mass in the exotic habitat. Despite having lower reproductive success in the exotic habitat, we found no evidence that Chestnut-collared Longspurs preferred to nest in the native habitat. Our results show that the introduction and spread of a commonly planted exotic grass has adverse fitness consequences for a grassland bird, and highlight the importance of maintaining native prairie.Éxito Reproductivo de Calcarius ornatus en Praderas Nativas y ExóticasResumen. La pérdida y fragmentación de hábitat han sido identificados como factores importantes con respecto a la disminución de las poblaciones de aves de pastizales. Sin embargo, las poblaciones están en disminución aún en ecosistemas de pradera relativamente intactos, lo que sugiere que otros factores están involucrados en el proceso. La degradación del hábitat de nidificación podría ser uno de estos factores adicionales, pero pocos estudios han examinado la demografía de aves de pastizales en distintos hábitats. En consecuencia, se conoce muy poco acerca de cómo los cambios en el hábitat podrían estar relacionados con las disminuciones poblacionales. En este estudio abordamos esta pregunta comparando el éxito reproductivo de individuos de la especie Calcarius ornatus en parches de praderas nativas y en monocultivos de Agropyron cristatum, un pasto introducido de Asia. Empleando métodos recientemente desarrollados para estimar la tasa de supervivencia de los nidos, encontramos que independientemente del tipo de hábitat, la supervivencia diaria de los nidos en general disminuyó desde la puesta hasta el momento de emplumamiento de los pichones. También encontramos un efecto positivo del tamaño de la nidada sobre la tasa de supervivencia de los nidos, el cual interpretamos como evidencia de que existe heterogeneidad individual en la supervivencia de los nidos. Finalmente, encontramos que en el ambiente exótico la probabilidad de sobrevivir de un nido durante un día dado fue un 17% menor, los pichones crecieron más lentamente y presentaron una masa final menor. A pesar de presentar un éxito reproductivo menor en el ambiente exótico, no encontramos evidencia de que las aves prefirieran nidificar en el ambiente nativo. Nuestros resultados muestran que la introducción y propagación de un pasto exótico que es plantado con frecuencia tiene efectos adversos sobre la adecuación de un ave de pastizal, y resaltan la importancia de mantener las praderas nativas.

Characterising essential breeding habitat for whales informs the development of large-scale Marine Protected Areas in the South Pacific

2016 ◽  
Vol 548 ◽  
pp. 263-275 ◽  
Author(s):  
RE Lindsay ◽  
R Constantine ◽  
J Robbins ◽  
DK Mattila ◽  
A Tagarino ◽  
...  
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Large Scale ◽  
South Pacific ◽  
Breeding Habitat ◽  
The South

scholarly journals Scaling up private land conservation to meet recovery goals for grassland birds

2021 ◽  
Author(s):  
David C. Pavlacky ◽  
Christian A. Hagen ◽  
Anne M. Bartuszevige ◽  
Rich Iovanna ◽  
T. Luke George ◽  
...  
Keyword(s):  
Grassland Birds ◽  
Scaling Up ◽  
Land Conservation ◽  
Private Land ◽  
Private Land Conservation

scholarly journals Patch Size and Landscape Effects on Density and Nesting Success of Grassland Birds

2006 ◽  
Vol 70 (1) ◽  
pp. 158-172 ◽  
Author(s):  
MAIKEN WINTER ◽  
DOUGLAS H. JOHNSON ◽  
JILL A. SHAFFER ◽  
THERESE M. DONOVAN ◽  
W. DANIEL SVEDARSKY
Keyword(s):  
Patch Size ◽  
Grassland Birds ◽  
Nesting Success ◽  
Landscape Effects

scholarly journals Factors affecting nest-site selection of Sabine's Gulls in the eastern Canadian Arctic

2005 ◽  
Vol 83 (9) ◽  
pp. 1240-1245 ◽  
Author(s):  
Iain J Stenhouse ◽  
H Grant Gilchrist ◽  
William A Montevecchi
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Nest Site Selection ◽  
Breeding Habitat ◽  
Factors Affecting ◽  
Invertebrate Prey ◽  
Terrestrial Invertebrate ◽  
Individual Fitness ◽  
Sabine’S Gull ◽  
Selection Of

The selection of breeding habitat is of prime importance for individual fitness. Among birds, natural selection should favour the ability to recognize and select habitat suitable for nesting and rearing chicks. This study compares the characteristics of Sabine's Gull, Xema sabini (Sabine, 1819), nest sites with random points across a coastal tundra environment on Southampton Island, Nunavut, Canada. The availability of terrestrial invertebrate prey was also examined among habitats. Sabine's Gull nests were nonrandomly distributed in relation to vegetation, substrate, and proximity to water. Gulls nested within approximately 1 km of the coastline and selected sites with the greatest proportions of moss and standing water (i.e., they nested close to the edge of small freshwater ponds near shore). However, there were no detectable differences in characteristics between successful and unsuccessful nests within preferred habitat. The dynamics of terrestrial invertebrate prey communities varied between years, but the volume of invertebrates in Sabine's Gull nesting habitat was intermediate between the most productive habitats and the least productive habitats in both years. However, nest-site selection in Sabine's Gulls may also be influenced by the availability of aquatic invertebrates (not examined in this study) and their proximity to the marine coastline, where chicks are taken to be reared.

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