Variations in pest bird density in Argentinean agroecosystems in relation to land use and/or cover, vegetation productivity and climate

2018 ◽  
Vol 45 (8) ◽  
pp. 668 ◽  
Author(s):  
Noelia C. Calamari ◽  
Sonia B. Canavelli ◽  
Alexis Cerezo ◽  
Sebastián Dardanelli ◽  
Jaime N. Bernardos ◽  
...  
Keyword(s):  
Land Use ◽  
Population Distribution ◽  
Bird Species ◽  
Crop Damage ◽  
Vegetation Productivity ◽  
Monk Parakeet ◽  
Bird Populations ◽  
Myiopsitta Monachus ◽  
Bird Density

Context Changes in environmental conditions may influence bird populations, including pest bird species, and their distribution. In Argentina, particularly in the Pampas region, agricultural expansion has resulted in important changes in agroecosystems, with impacts on bird species. Aims This study analysed the relationship between pest bird densities and the environmental variables associated with land use and/or cover, vegetation productivity and climate. The study focused on the most important pest bird species to grain crops in Argentina and Uruguay: the eared dove (Zenaida auriculata) and the monk parakeet (Myiopsitta monachus). Methods An area in Central Argentina was divided into three agro-productive regions, one predominantly agricultural and two with mixed production activities: agricultural rangeland and agricultural forested rangeland. Bird populations were sampled on a yearly basis between 2003 and 2011 in point-transects located along secondary roads (47 routes in total). Linear mixed models and a multi-model inference approach were used to compare the effects of individual predictive variables on bird densities. Key results Mean estimated density for the eared dove was 0.39 individuals per ha (±0.02), almost three times the density of the monk parakeet (0.10 individuals per ha±0.02). The spatial distribution of changes in density of the eared dove and monk parakeet showed irregular patterns across the study area. Density of eared dove was directly related to cover of native and exotic woodlots and inversely related to cover of fallow and weedy fields, and to temperature and rainfall. Monk parakeet density, in turn, was directly related to cover of woodlots. Conclusions The density of eared doves and monk parakeets changed mostly in relation to land use and/or cover and, to a lesser extent, to climatic conditions. Information of pest bird populations in a long-term period allowed us to understand spatial patterns in bird population distribution and to identify the main environmental factors explaining them. Implications The consideration of land use and/or cover, vegetation productivity and climate variables at regional scale, measured during a long-term period, would be critical for anticipating population increases and, possibly, increases in crop damage.

scholarly journals Dietary plasticity in an invasive species and implications for management: the case of the monk parakeet in a Mediterranean city

2021 ◽  
pp. 185-194
Author(s):  
J. L. Postigo ◽  
J. Carrillo-Ortiz ◽  
J. Domènech ◽  
X. Tomàs ◽  
L. Arroyo ◽  
...  
Keyword(s):  
Invasion Success ◽  
Crop Damage ◽  
Foraging Strategies ◽  
Behavioural Flexibility ◽  
Monk Parakeet ◽  
Myiopsitta Monachus ◽  
Relevant Role ◽  
Dietary Plasticity ◽  
Anthropogenic Food ◽  
Food Consumed

Behavioural flexibility may play a relevant role during invasion of a new habitat. A typical example of behavioural flexibility favouring invasion success refers to changes in foraging behaviour. Here we provide data on changes in the foraging strategies of monk parakeets Myiopsitta monachus over a period of 17 years (2001–2017) in Barcelona city. During this time, consumption of food on the ground increased by more than 25 % and the consumption of anthropogenic food increased by 8 %. Detailed information about the food consumed is provided. Feeding on the ground and consumption of low plants allow parakeets to reach not only anthropogenic food but also crops, thereby increasing the risk of crop damage as the invasion evolves. Early detection of damage to crops is crucial in order to prevent further harm, and makes the precautionary principle highly relevant.

Summer and winter bird populations associated with five age-classes of aspen forest in Alberta

1993 ◽  
Vol 23 (9) ◽  
pp. 1830-1836 ◽  
Author(s):  
D. A. Westworth ◽  
E. S. Telfer
Keyword(s):  
Habitat Structure ◽  
Bird Species ◽  
Canopy Cover ◽  
Species Number ◽  
Age Classes ◽  
Bird Populations ◽  
Clear Cut ◽  
Number Of Species ◽  
Bird Density ◽  
Large Trees

Summer and winter bird use of aspen forests was studied in west central Alberta. Forest age-classes in the study included 1- and 2-year-old clear-cut areas and.14-, 30-, 60-, and 80-year-old stands. Habitat structure and composition were quantified by a combination of measurement and estimation of variables. Density of the breeding bird population was estimated by territorial mapping. Changes in habitat structure between different age-classes resulted in a successional replacement of bird species. Number of individuals was greatest in 14-year-old stands at 656 territories per 100 ha, probably owing to the presence of remnant snags and of large trees that had survived past fires. The 30-year-old stands supported 312 territories per 100 ha, 60-year-old stands 380 territories, and 80-year-old stands 231 territories, respectively. Recently clear-cut areas supported only 110 territories. Number of species followed the same pattern with 25 in 14-year-old stands, 22 in the 30-year-old stands, 21 in the 60-year-old stands, and 14 in the 80-year-old stands. Recent clearcuts supported 10 species. In winter 13 bird species were recorded in the combined clear-cut, 14-, 30-, and 60-year-old stands. The highest number of species (11) were recorded in the 60-year-old stand during winter but the greatest winter bird density (125 individuals/100 ha) occurred in the 30-year-old stand. Three principal components extracted from the habitat data explained 83.2% of the variance in bird use. The components corresponded to gradients in canopy cover, occurrence of conifers, and shrub density.

scholarly journals Monitoring Breeding Bird Populations in Grand Teton National Park: 1995-1997

1997 ◽  
Vol 21 ◽  
pp. 13-25
Author(s):  
Martin Cody ◽  
Stephen Cain
Keyword(s):  
Breeding Season ◽  
National Park ◽  
Management Strategies ◽  
Bird Species ◽  
Breeding Habitat ◽  
Breeding Bird ◽  
Grand Teton National Park ◽  
Bird Populations ◽  
The Impact

In summer 1997 our NPS-funded project # CA-1460-5-0010, covering a 3-y period from summer 1995 through summer 1997, was completed. The immediate goals of the project were to instigate a system for monitoring the densities of breeding bird species, by establishment of flxed sites as a basis for a long term monitoring plan and of census protocols that can detect changes of breeding species and their densities over successive years. The monitoring scheme is conducted largely within Grand Teton National Park (GTNP), but covers habitats and an avifauna representative of the Greater Yellowstone Ecosystem (GYE) and the central-northern Rocky Mountains in general. The project emphasizes the need for long­term and on-going studies on breeding bird species and densities and their importance as a tool for evaluating the impact of both local and distant influences on breeding bird populations. For residents, species that remain all year in or near the breeding habitat, local effects include those operating on-site during the non-breeding season as well as during the breeding season. For migrant species, those that breed on-site but leave to spend the non-breeding season in other locations, often distant and usually of quite different habitat composition, there are both on-site influences on breeding population densities, such as inter-year changes in vegetation structure and productivity, and off-site or distant influences, including factors that affect over-wintering success in the non­breeding habitat and others that influence a successful transit between wintering and breeding grounds. The assessment of long-term trends in bird densities may be used as a form of bioassay of the state of the local environments. Information from such studies can provide region-wide indicators that, given a sufficiently comprehensive data base, can segregate local from distant influences on populations. Such indicators can be incorporated into management strategies to aid in determining which local strategies may be necessary (and feasible) to help maintain the biota.

scholarly journals Breeding Bird Communities in a Naturally Fragemented Forest Ecosystem in Grand Teton National Park

1998 ◽  
Vol 22 ◽  
pp. 37-37
Author(s):  
Gregory Schrott
Keyword(s):  
Habitat Fragmentation ◽  
National Park ◽  
Bird Species ◽  
Bird Communities ◽  
Western North America ◽  
Breeding Bird ◽  
Grand Teton National Park ◽  
Bird Populations ◽  
Natural Processes

This project examined the bird species breeding in the morainal forests on the valley floor in Grand Teton National Park. These forests are very patchily distributed and range in size from less than 1 hectare to over 700 hectares, allowing for a unique opportunity to study the responses of the local bird species to a forest system that has been fragmented for centuries through natural processes. This information can be useful for predicting the potential long-term impacts of human-caused forest fragmentation on bird populations in western North America. Until quite recently very little was known of the tolerances of western forest bird species to habitat fragmentation and this project could represent an important step towards understanding their needs in this regard.

scholarly journals The dynamics of avicultural markets

2001 ◽  
Vol 28 (1) ◽  
pp. 76-85 ◽  
Author(s):  
Jennifer M. Robinson
Keyword(s):  
Captive Breeding ◽  
Bird Species ◽  
Decision Makers ◽  
Trade Restrictions ◽  
Model Simulations ◽  
Species Introductions ◽  
Bird Populations ◽  
Potential Source ◽  
The World

Trade restrictions stemming from the Convention on International Trade in Endangered Species (CITES) have created a situation in which rare and attractive bird species command high prices on international pet markets. Most of these species are of tropical or subtropical origin, and many are amenable to captive breeding. Hence, the possibility of exporting birds under CITES provisions for the export of captive-raised animals is under debate in many countries around the world. If export bans are replaced by systems of export permits, the economics of avicultural markets will govern the magnitude, timing, and nature of the impacts of the bird trade. Avicultural economics, however, is little studied, and the long-term economic viabilities of exotic pet markets are poorly understood. In order to elucidate these, a dynamic model of an avicultural market was constructed, based on descriptive information. Model simulations showed that the high prices commanded by sought-after bird species tended to bring about oversupply and rapid price decline. Short-lived, fecund species produced a rapid, sharp pulse of oversupply; longer-lived species produced more persistent but less acute conditions of oversupply. The present high prices for protected bird species may be regarded as a potential source of windfall profits, or as a factor that might be manipulated to discourage the poaching and smuggling of wild birds. If export-oriented aviculture is considered as a component of strategies for diversification of agriculture and promotion of sustainable development, it is important that decision-makers factor in the likelihood of significant declines in bird prices and that they consider the risk of accidental species introductions that is inherent in holding large exotic-bird populations.

scholarly journals Do Invasive Mosquito and Bird Species Alter Avian Malaria Parasite Transmission?

Diversity ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 111 ◽  
Author(s):  
Josué Martínez-de la Puente ◽  
Alazne Díez-Fernández ◽  
Tomás Montalvo ◽  
Rubén Bueno-Marí ◽  
Quentin Pangrani ◽  
...  
Keyword(s):  
Urban Areas ◽  
Mosquito Species ◽  
Bird Species ◽  
Blood Feeding ◽  
Invasive Pest ◽  
Monk Parakeet ◽  
Myiopsitta Monachus ◽  
Asian Tiger ◽  
Invasive Mosquito ◽  
High Fraction

Alien mosquito and vertebrate host species may create novel epidemiological scenarios for the transmission of pathogens naturally circulating in the invaded area. The exotic Monk parakeet (Myiopsitta monachus) has established populations in Europe and is currently considered an invasive pest. Due to their high abundance in urban areas, Monk parakeets could be involved in the transmission of pathogens, potentially affecting wildlife and livestock. To test this hypothesis, we determined the prevalence and diversity of three vector-borne parasites, namely Plasmodium, Haemoproteus and Leucocytozoon, in Monk parakeets from Barcelona. Many areas of southern Europe shelter high densities of the invasive Asian tiger mosquito Aedes albopictus, which in addition to native mosquito species could affect the transmission of mosquito-borne parasites, such as avian Plasmodium. Thus, we also sampled mosquitoes in the area to trace their blood-feeding hosts and determine the presence of Plasmodium parasites. Monk parakeets were neither infected by Plasmodium nor by Haemoproteus parasites, and only five individuals (3.13%; n = 160) were infected by Leucocytozoon. Monk parakeets were bitten by Culiseta longiareolata and represented 9.5% of Culex pipiens blood meals. The invasive Ae. albopictus showed a clear anthropophilic feeding pattern, with humans dominating its diet. Three Plasmodium lineages were detected in pools of Cx pipiens. These results suggest that Plasmodium circulating in the area cannot develop in the invasive Monk parakeet, in spite of the relatively high fraction of native mosquito vectors feeding on this species in its invaded distribution range.

scholarly journals Long-term declines in bird populations in tropical agricultural countryside

2019 ◽  
Vol 116 (20) ◽  
pp. 9903-9912 ◽  
Author(s):  
Çağan H. Şekercioğlu ◽  
Chase D. Mendenhall ◽  
Federico Oviedo-Brenes ◽  
Joshua J. Horns ◽  
Paul R. Ehrlich ◽  
...  
Keyword(s):  
Protected Areas ◽  
Bird Species ◽  
Agricultural Landscapes ◽  
Tree Cover ◽  
Conservation Value ◽  
Coffee Plantations ◽  
Forest Bird ◽  
Bird Populations ◽  
Capture Rates

Tropical agriculture is a major driver of biodiversity loss, yet it can provide conservation opportunities, especially where protected areas are inadequate. To investigate the long-term biodiversity capacity of agricultural countryside, we quantified bird population trends in Costa Rica by mist netting 57,255 birds of 265 species between 1999 and 2010 in sun coffee plantations, riparian corridors, secondary forests, forest fragments, and primary forest reserves. More bird populations (69) were declining than were stable (39) or increasing (4). Declines were common in resident, insectivorous, and more specialized species. There was no relationship between the species richness of a habitat and its conservation value. High-value forest bird communities were characterized by their distinct species composition and habitat and dietary functional signatures. While 49% of bird species preferred forest to coffee, 39% preferred coffee to forest and 12% used both habitats, indicating that coffee plantations have some conservation value. Coffee plantations, although lacking most of the forest specialists, hosted 185 bird species, had the highest capture rates, and supported increasing numbers of some forest species. Coffee plantations with higher tree cover (7% vs. 13%) had more species with increasing capture rates, twice as many forest specialists, and half as many nonforest species. Costa Rican countryside habitats, especially those with greater tree cover, host many bird species and are critical for connecting bird populations in forest remnants. Diversified agricultural landscapes can enhance the biodiversity capacity of tropical countryside, but, for the long-term persistence of all forest bird species, large (>1,000 ha) protected areas are essential.

scholarly journals The forest avifauna of Arabuko Sokoke Forest and adjacent modified habitats

2021 ◽  
Author(s):  
David Chiawo ◽  
Wellington N. Kombe ◽  
Adrian J.F.K. Craig
Keyword(s):  
Land Use ◽  
Habitat Use ◽  
Bird Species ◽  
Bird Community ◽  
Primary Forest ◽  
Future Research ◽  
Coastal Forest ◽  
Plantation Forest ◽  
Bird Populations ◽  
Vegetation Heterogeneity

Arabuko Sokoke Forest (ASF) is the largest area of coastal forest remaining in East Africa and a major Important Bird Area in mainland Kenya. The study analysed data from point count surveys over 15 months in three land use types; primary forest (PF), plantation forest (PL), and farmlands (FM), and compared these to the first comprehensive bird checklist for the forest, as well as recent surveys from other studies.  Avifaunal diversity and abundance were compared using multivariate analysis to determine bird responses to different land use characteristics. The primary forest held a distinctive bird community, while the bird communities of farmlands and plantation forest were more similar to each other. Land use had a significant effect on overall avian diversity and abundance. The current forest avifauna was divided into forest specialists (16 species), forest generalists (26 species) and forest visitors (30 species).   Seven species of forest specialist and generalists recorded prior to 1980 may no longer occur in the forest.  Of 38 specialists and generalists recorded in our point counts, 19 were also recorded on farmland and 28 in plantations.  One forest specialist, the Green Barbet, was most encountered outside the forest.  Future research should focus on habitat use by these bird species, and the extent of movement by forest birds between the remaining patches of coastal forest. Patterns of habitat use by birds in the area suggest that vegetation heterogeneity and habitat complexity are especially significant in sustaining diverse and abundant bird populations. The management of plantations and farmland will be critical for the conservation of forest generalists and forest visitors.

Patterns of association between birds and invertebrates in the Clyde Estuary

1986 ◽  
Vol 90 ◽  
pp. 185-201
Author(s):  
D. B. A. Thompson ◽  
D. J. Curtis ◽  
J. C. Smyth
Keyword(s):  
Prey Availability ◽  
Bird Species ◽  
Stepwise Multiple Regression ◽  
Estuarine Ecosystem ◽  
Bird Density ◽  
Tidal State ◽  
Tidal Movement ◽  
Variation Explained ◽  
Bird Distribution

SynopsisRelationships between feeding ecology, population dynamics and conservation of estuarine shorebirds are becoming better understood mainly as a result of detailed long-term studies of birds in the northwest European estuaries most vulnerable to industrial and agricultural developments. Until five years ago the tidal flats of the Clyde Estuary held internationally and nationally important populations of ducks (Anatinae) and waders (Charadrii). To understand the reasons for changes in bird distribution it is necessary to know more about the factors which determine distribution. In this paper we examine the pattern of association between the Clyde's birds and their prey by evaluating the extent to which the distribution of birds is related to that of benthic invertebrates, heterospecific birds, season and tidal state.Stepwise multiple regression analysis indicated that heterospecifics had effects on bird distributions over-riding those of prey. In summer, the significant independent variables explained 41–61% variation in bird density (number km−2) and 33% variation in bird feeding hours (bird-hours km−2); in winter they explained 17–35% and 29–32% respectively. The amount of variation explained was greater during flow than ebb tides, and the number of species for which some of the variation was explained was greater in winter than in summer. Three associations, each consisting of two bird species, are suggested: redshank with lapwing, dunlin with mallard, and shelduck with gulls. We provide explanations for some of the mechanisms underlying the above patterns and indicate areas for more detailed observational and experimental work. The integrity of the avian component of the estuarine ecosystem appears to be dependent on associations and interactions between birds as well as between birds and their prey. The associations are labile, and in many species stem from the effect of tidal movement on prey availability.

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