A new threat for the globally Endangered Hooded Grebe Podiceps gallardoi : the American mink Neovison vison .

Bird Conservation International

2013

Self Cite

SummaryWe present the results of searches for the Austral Rail Rallus antarcticus in Argentine and Chilean Patagonia between January 1998 and February 2006 and from subsequent visits. We surveyed 58 localities and found the rail in 22, which collectively cover approximately 85 km2 of habitat. A maximum of 175 individuals were detected. This poorly known species was rediscovered in 1998; since then, it has been found in 18 additional localities, providing further data on distribution, habitat and seasonal movements. During the searches, we found that the species faces different threats, such as reduction of wetlands due to cattle grazing, burning and abnormal water management, but also the presence of American mink Neovison vison. However, due to the lack of prior information we conclude that the species should be maintained as Vulnerable.

Section: Discussionmentioning

confidence: 99%

Distribution and habitat use of the Austral Rail Rallus antarcticus and perspectives on its conservation

Barnett¹,

Imberti

Bird Conservation International

2013

Self Cite

“…The main plateaus from north to south are: "Buenos Aires", "Asador", "Strobel", "Ventana", "Moro", "Siberia", "Viedma" and "Vizcachas" ( Figure 1A); they extend from 47°S to 51°S, with elevations varying between 500 and 1,500 m asl. These plateaus areas range from 30 to 2,900 km 2 and hold endorheic volcanic and non-volcanic lakes that accumulate water from precipitation and snow melt during winter, their number varying greatly among plateaus (Roesler et al 2012). The physicochemical characteristics of water in these lakes are mainly determined by the composition of the underlying bedrock, which results in a wide diversity of limnological characteristics (Lancelotti et al 2009).…”

Section: Study Sitementioning

confidence: 99%

Hooded GrebePodiceps gallardoipopulation decreased by eighty per cent in the last twenty-five years

Bird Conservation International

Imberti

Casañas³

et al. 2012

Self Cite

SummaryWe estimated the present population size of the Hooded Grebe Podiceps gallardoi and compared it with the population in 1985. During the breeding seasons 2009/2010 and 2010/2011 we monitored 251 lakes on the main plateaus of Santa Cruz province, southern Patagonia, Argentina, where the entire population of Hooded Grebes spends the breeding season. During 2009/2010 we monitored 131 lakes and observed 521 Hooded Grebes in 16 lakes, while during 2010/2011 we monitored 186 lakes and observed 535 individuals in 14 lakes. At both breeding seasons five lakes contained near 85% of the population. We only observed 6 breeding colonies, two in 2009/2010 and four in 2010/2011, totalling 242 nesting attempts. Nearly 90% of the nests failed during egg stage, mainly due to strong winds and depredation by American mink Neovison vison. Only 28 nests hatched chicks, but none of the young survived to independence due to low temperatures. We compared the results of our 2010/2011 survey with one conducted during 1984/1985 and detected that the population diminished by approximately 80%. This decline was observed on all but one plateau (“Buenos Aires”) where most breeding attempts occurred. Our results show that at present Hooded Grebes are highly dependent on a few suitable lakes where they congregate to breed. We analyse possible causes for the decline of the population and propose conservation actions to protect this species.

“…During the reproductive period (spring–autumn) the hooded grebe inhabits lakes within an array of nine elevated (600 m a.s.l.) basaltic plateaus of southern Patagonia, migrating to river estuaries on the southern Atlantic coast for overwintering (Fjeldså, ; Beltrán, Bertonatti, Johnson, Serret, & Sutton, 1992; Roesler, Imberti, Casañas, & Volpe, ). It reproduces only in mid‐size lakes (0.05–0.7 km 2 ), and among the large array of lakes available in the plateaus displays a clear preference for those with abundant emergent macrophytes and surrounding areas with open water (Lancelotti, Pozzi, Yorio, Diéguez, & Pascual, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…The introduction of rainbow trout ( Oncorhynchus mykiss ) in lakes of the plateaus, the predation by alien American mink ( Neovison vison ), the consumption of eggs and chicks by a growing population of kelp gull ( Larus dominicanus ) – favoured by the proliferation of garbage dumps – and the occurrence of extremely dry periods have all been proposed as major threats for this species (Lancelotti, Marinone, & Roesler, 2017; Roesler, Imberti, Casañas, Mahler, & Reboreda, ; Roesler, Imberti, Casañas, & Volpe, ; Fasola & Roesler, ). Although several studies have concentrated on the impacts of new predators and competitors, the effects of changes in habitat availability in response to regional climate is virtually unexplored.…”

Section: Introductionmentioning

confidence: 99%

Climate variability and trends in the reproductive habitat of the critically endangered hooded grebe

Lancelotti

Pessacg

et al. 2020

Aquatic Conservation

The population of the critically endangered hooded grebe (Podiceps gallardoi) has decreased drastically during recent decades. The effects of climate change on their reproductive area (Southern Patagonia) have been proposed as one of the potential causes of their critical situation. However, there is much uncertainty about climate variability and climate trends at local scales in Patagonia, and their effects on the hooded grebe habitat. Variability and trends in temperature, precipitation, and wind from 1960 to 2016 in one of the most important reproductive areas of hooded grebe – the Lake Strobel plateau – were analysed. A Landsat satellite image series (1973–2016) was used to evaluate changes in lake area in the region. Generalized linear models were used to analyse the relationship between the variation in lake area and climatic variables, including the Antarctic Oscillation Mode (AAO) index, which is the most important year to year pattern in climate variability at high latitudes of the Southern Hemisphere. High inter‐annual variability and increasing coefficients of variation in precipitation and wind were found, as well as a significant positive trend in temperature. Total lake area, as well as the area specifically used by hooded grebe to reproduce, decreased significantly over time, with high inter‐annual variability. Variation in lake area was significantly correlated with variation in precipitation, and with the AAO index. The loss of reproductive habitat may force the hooded grebe to use sub‐optimal environments, such as lakes with lower food supply, lower macrophyte cover, and less protection from wind – a potential major handicap for this declining species. Information on lake variation in response to climatic variability could be used to guide hooded grebe conservation strategies, directing more resources and special efforts to those reproductive lakes that are more resilient to the effects of climate fluctuations.