scholarly journals Abundance Estimates of the Lesser Rhea Rhea pennata pennata in the Argentine Patagonia: Conservation Implications

2015 ◽  
Vol 3 ◽  
Author(s):  
Ricardo Baldi ◽  
Analía Pirronitto ◽  
María V. Burgi ◽  
Milagros Antún
Keyword(s):  
Conservation Implications ◽  
Argentine Patagonia ◽  
Abundance Estimates ◽  
Lesser Rhea

scholarly journals Response of guanacosLama guanicoeto changes in land management in Península Valdés, Argentine Patagonia: conservation implications

Oryx ◽  
2011 ◽  
Vol 46 (1) ◽  
pp. 99-105 ◽  
Author(s):  
María Virginia Burgi ◽  
Andrea Marino ◽  
María Victoria Rodríguez ◽  
Gustavo Pazos ◽  
Ricardo Baldi
Keyword(s):  
Protected Area ◽  
Habitat Degradation ◽  
Plant Cover ◽  
Management Plan ◽  
Ovis Aries ◽  
Domestic Sheep ◽  
Large Herbivore ◽  
Conservation Implications ◽  
Argentine Patagonia ◽  
Sheep Production

AbstractThe guanacoLama guanicoewas the only large native herbivore widely distributed across Patagonia until the introduction of domestic sheepOvis aries. Guanacos have declined because of competition with sheep for forage, high hunting pressure and habitat degradation. Península Valdés is a protected area where sheep ranching is the predominant activity. A ranch formerly dedicated to sheep production was converted into a private wildlife reserve, from which all the sheep were removed in 2005. We studied changes in guanaco abundance inside and outside the reserve after sheep removal, and also plant cover of various vegetation types. We found that guanaco abundance was higher inside than outside the reserve, and increased by three-fold within 3 years. Total plant cover and grass cover were higher inside than outside the reserve. Our results showed that guanacos reacted rapidly to changes in management, and suggest that even at a high density guanacos would not be as damaging to the vegetation as sheep. Although management changes resulted in significant changes in guanaco abundance locally, the size of a protected area influences the persistence of wild populations. A large herbivore such as the guanaco needs to be managed across large areas. We believe it is necessary to implement a management plan for Península Valdés that allows for the coexistence of sustainable livestock production and healthy wildlife populations.

scholarly journals The ecological role of native and introduced species in the diet of the puma Puma concolor in southern Patagonia

Oryx ◽  
2012 ◽  
Vol 46 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Juan Ignacio Zanón Martínez ◽  
Alejandro Travaini ◽  
Sonia Zapata ◽  
Diego Procopio ◽  
Miguel Ángel Santillán
Keyword(s):  
Protected Areas ◽  
Native Species ◽  
Prey Species ◽  
Puma Concolor ◽  
Lepus Europaeus ◽  
Main Prey ◽  
Argentine Patagonia ◽  
Lesser Rhea ◽  
Southern Patagonia ◽  
North Western

AbstractThere is evidence for the ecological extinction of the native prey of the puma Puma concolor in north-western Argentine Patagonia. In this study we examine whether this is also the case in southern Patagonia. From 2004 to 2007 we examined the puma’s diet in three protected areas and two sheep ranches in Santa Cruz province. A total of 282 puma scats were analysed. In two of the protected areas and in the ranches 60–74% of the puma’s diet was native prey. Prey species were primarily guanaco Lama guanicoe, followed by Patagonian mara Dolichotis patagonum, lesser rhea Pterocnemia pennata pennata, Patagonian pichi Zaedyus pichiy and Magellanic penguin Spheniscus magellanicus. In the third protected area the main prey was the European hare Lepus europaeus. Our results show a clear difference in the diet of the puma in southern compared to north-western Patagonia. Large native herbivores (i.e. guanaco and lesser rhea) maintain their role as the main prey species for the puma in southern Patagonia. We suggest, therefore, that native prey could be restored to those areas of Argentine Patagonia, such as the north-west, where they are currently ecologically extinct. Facilitating native species recovery and/or restoration and applying more rigorous controls to prevent the introduction of potential alien prey species of the puma both, within and outside protected areas, needs to be evaluated as a regional strategy.

Analysis of the spatial variation in the abundance of lesser rheas using density surface models

2018 ◽  
Vol 45 (1) ◽  
pp. 47 ◽  
Author(s):  
Milagros Antún ◽  
Ricardo Baldi ◽  
Lucas M. Bandieri ◽  
Romina L. D' Agostino
Keyword(s):  
Spatial Variation ◽  
Vegetation Index ◽  
Austral Summer ◽  
High Resolution Data ◽  
Argentine Patagonia ◽  
Lesser Rhea ◽  
Normalised Difference Vegetation Index ◽  
Surface Models ◽  
Density Surface ◽  
Sampling Procedures

Context The study of the spatial variation in abundance of wild populations and the identification of factors explaining the observed patterns are key both to understand aspects of basic ecology and the effects of human activities. This is usually difficult to evaluate for low-density and widely distributed species, such as the lesser rhea (Rhea pennata pennata), an endemic bird from South America. Recent advances in spatial modelling such as the density surface models (DSM) combine distance-sampling procedures with modelling techniques to produce maps of spatial variation in abundance, and its relationship with predictive variables. Aims We aimed to analyse the spatial distribution and abundance of lesser rhea, and the variables that affect its abundance in Península Valdés (PV) Argentine Patagonia. Methods We conducted 338.4 km of ground surveys of lesser rheas in PV during the end of the Austral summer of 2015. Spatial models were constructed using DSM. Ecological and human-related variables were included in the models to account for variation in the abundance of animals at 4-km2 spatial resolution. Key results We estimated an overall density of 0.44 birds km–2 (CV = 32%) for the prediction area of 3320 km2. High values of normalised difference vegetation index, a correlate of plant productivity, were associated with increased numbers of lesser rheas. The location of ranch buildings, indicators of human presence, had a strong negative effect on lesser rheas, although their abundance increased at high sheep stocking rates. Conclusions As reported by previous studies in different sites, the abundance of lesser rheas in our study area was low. The use of DSM allowed a detailed examination of the spatial variation, as well as the variables involved and the uncertainty of the prediction. Implications The use of DSM techniques can be a useful tool for conservation planning and monitoring. Spatial, high-resolution data combined with knowledge on the factors affecting the number of animals are crucial to target specific conservation actions and monitor their results, and should allow government agencies to make better decisions concerning conservation-oriented management.

Abundance Estimates of Guiana Dolphins (Sotalia guianensis; Van Bénéden, 1864) Inhabiting an Estuarine System in Southeastern Brazil

2019 ◽  
Vol 45 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Aline B. de Mello ◽  
Julia M. B. Molina ◽  
Maja Kajin ◽  
Marcos C. de O. Santos
Keyword(s):  
Southeastern Brazil ◽  
Estuarine System ◽  
Sotalia Guianensis ◽  
Abundance Estimates

Stranding cases of endangered Ganges river dolphins in the Ghaghara–Sharada irrigation canals, Ganges river basin, India: conservation implications

Mammalia ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Shakti Prajapati
Keyword(s):  
River Basin ◽  
Local Population ◽  
Uttar Pradesh ◽  
Ganges River ◽  
Population Declines ◽  
Irrigation Canals ◽  
Indus River ◽  
River Dolphin ◽  
Conservation Implications ◽  
Media Reports

AbstractPopulations of endangered Ganges and Indus river dolphins have been under severe threat from diversion of river water by dams, barrages, and canal networks across the Indus and Ganges–Brahmaputra river basins. River dolphins prefer deep water and might enter irrigation canals in the dry-season, getting stranded there. Stranding can cause mortality and local population declines, and poses an emerging challenge to river dolphin conservation efforts. In Pakistan’s Indus river basin, stranding rates of Indus dolphins in irrigation canals are high, and well-coordinated rescue-release operations are undertaken. Despite commendable river dolphin rescue efforts in some parts of India, stranding cases are not always reported. From open-access media reports (2007–08 to 2017–18), I found 26 stranding cases of Ganges river dolphins from the Ghaghara–Sharada canal network across seven districts of Uttar Pradesh, India. Of these, 62% reports were from 2015 to 2016. Most cases occurred in secondary and tertiary canal branches. Interviews with fishers, farmers, and government officials revealed low awareness of stranding cases. Stranded dolphins might have no chance of returning to their source habitat, unless rescued. From my results, I discuss how current barrage-canal operations could influence dolphin stranding risk, and their implications for flow management in the Ghaghara–Sharada river basin.

Bridled Quail-dove Geotrygon mystacea population assessment after hurricanes Irma and Maria, St. Eustatius, Caribbean Netherlands

2021 ◽  
pp. 1-12
Author(s):  
FRANK F. RIVERA-MILÁN ◽  
HANNAH MADDEN ◽  
KEVIN VERDEL
Keyword(s):  
National Park ◽  
Food Limitation ◽  
Distance Sampling ◽  
Population Status ◽  
Management Actions ◽  
Abundance Estimates ◽  
Detection Mode ◽  
Limited Food ◽  
Seed Eating ◽  
Free Ranging

Summary Structural vegetation damage and food limitation are important effects of major hurricanes, particularly for fruit/seed-eating, forest-dependent Caribbean birds with restricted distributions and small populations, such as the Bridled Quail-dove Geotrygon mystacea. Motivated by the lack of abundance estimates, corrected for detection probability, we conducted distance-sampling surveys inside and outside the Quill National Park each May in 2016-2019. Detection mode was the most important covariate, with others receiving no support from the data. Detectability of available single individuals and clusters of individuals within 60 m of transect centrelines averaged 0.957 ± 0.114 standard error for audio detections, 0.434 ± 0.052 for visual detections, and 0.693 ± 0.064 for detection modes combined. Availability averaged 0.475 ± 0.138 and the product of detectability and availability averaged 0.329 ± 0.098. Density averaged 1.459 ± 0.277 individuals ha-1 and population size averaged 642 ± 122 individuals in 440 ha. Density did not differ along and away from forest trails, but was higher inside than outside the park and at elevations within 201-400 m than 100-200 m and 401-600 m. Density declined by 76% after hurricanes Irma and Maria in 2017. We suggest that major hurricanes together with free-ranging livestock overgrazing degraded foraging habitats, limited food supply, and caused a population bottleneck. Our methodology can be implemented across the distribution range to assess population status and trends and evaluate the result of management actions at key conservation sites. Bridled Quail-dove populations probably were declining on most islands before the 2017 hurricanes and population status warrants revision.

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