Review of documented beak and feather disease virus cases in wild Cape parrots in South Africa during the last 20 years

Downs, Colleen T.; Brown, Mark; Hart, Lorinda A.; Symes, Craig T.

doi:10.1007/s10336-015-1258-6

Cited by 6 publications

(5 citation statements)

References 55 publications

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“…Further, warmer temperatures also mean that higher reproductive success and the survival rate of nestlings will depend on fruit availability (Wirminghaus et al., ), even if it means colonizing human‐modified lands. The intensity of drought in South Africa has elevated since 2011 aggravating outbreaks of Psittacine Beak and Feather Virus (Downs et al., ). Fluctuations in precipitation influenced the phenology of plant resources (Chambers et al., ) and availability of fruits for frugivores (Hart et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…Fluctuations in precipitation influenced the phenology of plant resources (Chambers et al., ) and availability of fruits for frugivores (Hart et al., ). However, low precipitation representing conditions of drought can have strong negative consequences on parrot populations through resource constraints (Ortiz‐Maciel, Salinas‐Melgoza, Valdéz‐Juárez, Lopez‐Toledo, & Enkerlin‐Hoeflich, ; Renton & Salinas‐Melgoza, ), and to add to such climatic stressors comes dangerous diseases that decrease the resilience of parrots (Downs et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…Annual surveys showed that parrots are sometimes absent from certain forest fragments (Downs, ), yet there are speculations that their occurrence has remained unchanged for nearly 50 years. With the increasing frequency of drought, juvenile Cape parrots are the most at risk of dying from diseases and/or secondary infections (Downs et al., ). Cape parrot populations continue to be threatened by illegal avicultural trade, hunting, and shooting by farmers, and habitat loss (Downs et al., , ; Lawes, Macfarlane, & Eeley, ; Lawes et al., ; Wirminghaus et al., ).…”

Section: Methodsmentioning

confidence: 99%

“…Climate and land cover as strong global forces of change bring unpredictable environmental variability. This poses dynamic threats to biodiversity by accelerating food shortages, enhancing physiological stress, decreasing species resilience to disease outbreaks, and increasing mortality (Downs, Brown, Hart, & Symes, ; Pearce‐Higgins & Green, ). These negative factors (Renton & Salinas‐Melgoza, ; Wormworth & Şekercioğlu, ) elevate the extinction risk of many tropical species particularly because of their sensitivity to environmental change (Beissinger & Snyder, ; Brooks, Pimm, & Oyugi, ; Keast, ; Şekercioğlu, Primack, & Wormworth, ) and habitat specializations (Downs, ; Downs, Pfeiffer, & Hart, ; Wirminghaus, Downs, Perrin, & Symes, ).…”

Section: Introductionmentioning

confidence: 99%

“…Significant warming trends and decreasing rainfall in South Africa, over the past 50 years (Kruger & Sekele, ; MacKellar, New, & Jack, ), have raised concerns for many forest endemics (Şekercioğlu et al., ; Simmons et al., ; Wormworth & Mallon, ). Since 2011, Cape parrots have increasingly shown low resistance to extreme catastrophe (Downs et al., ). Too hot and too cold weather may reduce reproduction and survival rates of Cape parrots (Wirminghaus et al., ).…”

Section: Introductionmentioning

confidence: 99%

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When and where to move: Dynamic occupancy models explain the range dynamics of a food nomadic bird under climate and land cover change

Kalle

Ramesh

Downs

2017

Global Change Biology

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Globally, long-term research is critical to monitor the responses of tropical species to climate and land cover change at the range scale. Citizen science surveys can reveal the long-term persistence of poorly known nomadic tropical birds occupying fragmented forest patches. We applied dynamic occupancy models to 13 years (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) of citizen science-driven presence/absence data on Cape parrot (Poicephalus robustus), a food nomadic bird endemic to South Africa. We modeled its underlying range dynamics as a function of resource distribution, and change in climate and land cover through the estimation of colonization and extinction patterns.The range occupancy of Cape parrot changed little over time (w = 0.75-0.83) because extinction was balanced by recolonization. Yet, there was considerable regional variability in occupancy and detection probability increased over the years.Colonizations increased with warmer temperature and area of orchards, thus explaining their range shifts southeastwards in recent years. Although colonizations were higher in the presence of nests and yellowwood trees (Afrocarpus and Podocarpus spp.), the extinctions in small forest patches (≤227 ha) and during low precipitation (≤41 mm) are attributed to resource constraints and unsuitable climatic conditions. Loss of indigenous forest cover and artificial lake/water bodies increased extinction probabilities of Cape parrot. The land use matrix (fruit farms, gardens, and cultivations) surrounding forest patches provides alternative food sources, thereby facilitating spatiotemporal colonization and extinction in the human-modified matrix. Our models show that Cape parrots are vulnerable to extreme climatic conditions such as drought which is predicted to increase under climate change. Therefore, management of optimum sized high-quality forest patches is essential for long-term survival of Cape parrot populations. Our novel application of dynamic occupancy models to long-term citizen science monitoring data unfolds the complex relationships between the environmental dynamics and range fluctuations of this food nomadic species.

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Section: Discussionmentioning

confidence: 99%