Effect of passage through the gut of Greater Rheas on the germination of seeds of plants of cerrado and caatinga grasslands

Azevedo, Cristiano Schetini de; Silva, Mayara Correa da; Teixeira, Tatiane Pinho; Young, Robert J.; Garcia, Queila de Souza; Rodrigues, Marcos

doi:10.1071/mu12070

Cited by 9 publications

(5 citation statements)

References 32 publications

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“…Rheas (Rhea americana) are birds of substantial size endemic to biomes in South America. These birds play a vital role as seed dispersers and serve as prey for large predators within their native ecosystems [1]. Regrettably, rheas are classified as near threatened globally by the International Union for the Conservation of Nature [2].…”

Section: Introductionmentioning

confidence: 99%

Changes in Sperm Morphology, Morphometry, and Motility from the Epididymis to the Vas Deferens in Rheas (Rhea americana, Linnaeus, 1758)

Bezerra

Jurema

Dantas

et al. 2023

Animals

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The objective was to characterize morphological, morphometric, and ultrastructural changes in rhea spermatozoa between the epididymis and the vas deferens. Sperm samples were collected from the reproductive tracts of seven adult individuals and evaluated for sperm characteristics using brightfield microscopy as well as ultrastructural features using scanning electron microscopy (SM). Mean sperm count tended to increase in the vas deferens (378.0 ± 135.0 × 106) compared to the epididymis (201.0 ± 77.4 × 106). Percentages of motile sperm grew from 37.0 ± 4.9% in the epididymis to 58.5 ± 7.7% in the vas deferens. The proportion of normal spermatozoa was 75.6 ± 1.8% and most common defects were bent tails (9.7 ± 0.9%). However, these proportions were not different between epididymis and vas deferens. SM analysis revealed further features of rhea spermatozoa. Normal rhea spermatozoa were threadlike with an acrosome (0.95 ± 0.0 µm), head (7.53 ± 0.01 µm), midpiece (2.08 ± 0.01 µm), and tail (30.7 ± 0.06 µm). Lengths of sperm acrosome, head, midpiece, and tail were longer in the vas deferens compared to the epididymis. Our findings suggest that rhea spermatozoa undergo a maturation process during the passage from the epididymis to the vas deferens.

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Section: Introductionmentioning

confidence: 99%

Changes in Sperm Morphology, Morphometry, and Motility from the Epididymis to the Vas Deferens in Rheas (Rhea americana, Linnaeus, 1758)

Bezerra

Jurema

Dantas

et al. 2023

Animals

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“…Seeds are carried by native animals, such as gray brocket (Mazama gouazoubira F.), black-rumped agouti (Dasyprocta prymnolopha W.), collared peccary (Pecari tajacu L.), fox (Dusicyon thous L.), yellow armadillo (Euphractus sexcinctus L.), argentine black and white tegu (Tupinambis merianae L.), greater rhea (Rhea americana L.) and white-naped jay (Cyanocorax cyanopogon Wied) (Barreto and Castro, 2010;Cavalcanti et al, 2009a;Cavalcanti and Resende, 2003;Azevedo et al, 2013). The non-native, human introduced cattle (Bos taurus L.) and goat (Capra hircus L.) are also reported dispersing seeds of S. tuberosa (Barreto and Castro, 2010;Griz and Machado, 2001).…”

Section: Restricted Seed Dispersalmentioning

confidence: 99%

Spondias tuberosa Arruda (Anacardiaceae), a threatened tree of the Brazilian Caatinga?

et al. 2016

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Spondias tuberosa Arr., a fructiferous tree endemic to the northeast Brazilian tropical dry forest called Caatinga, accounts for numerous benefits for its ecosystem as well as for the dwellers of the Caatinga. The tree serves as feed for pollinators and dispersers as well as fodder for domestic ruminants, and is a source of additional income for local smallholders and their families. Despite its vantages, it is facing several man-made and natural threats, and it is suspected that S. tuberosa could become extinct. Literature review suggests that S. tuberosa suffers a reduced regeneration leading to population decrease. At this juncture S. tuberosa cannot be considered threatened according to the International Union for Conservation of Nature Red List Categories and Criteria, as it has not yet been assessed and hampered generative regeneration is not considered in the IUCN assessment. The combination of threats, however, may have already caused an extinction debt for S. tuberosa. Due to the observed decline in tree density, a thorough assessment of the S. tuberosa population is recommended, as well as a threat assessment throughout the entire Caatinga.Keywords: Spondias tuberosa, natural regeneration, conservation, IUCN red list, Caatinga.Spondias tuberosa Arruda (Anacardiaceae), uma árvore ameaçada de extinção da Caatinga?Resumo Spondias tuberosa Arr., é uma árvore frutífera endêmica da Caatinga, floresta seca tropical localizada no Nordeste do Brasil. A árvore traz diversos benefícios para o ecossistema e para a população local. Ela serve de alimento tanto para polinizadores e dispersores quanto para ruminantes domésticos e é fonte de renda extra para os agricultores familiares da região. Apesar de seus benefícios, esta árvore enfrenta várias ameaças naturais e antrópicas que podem levar a sua extinção. A revisão da literatura científica sugere que S. tuberosa sofre de reduzida capacidade de regeneração, o que leva à diminuição da população. Todavia, S. tuberosa não é considerada uma espécie ameaçada de extinção de acordo com as categorias e critérios da Lista Vermelha da União Internacional para a Conservação da Natureza, já que a espécie ainda não foi avaliada e capacidade regenerativa reduzida não é considerado critério pelo UICN. A combinação de ameaças, entretanto, pode já ter levado ao débito de extinção da S. tuberosa. Devido ao declínio observado da densidade das árvores, recomenda-se uma avaliação completa da população de S. tuberosa e uma avaliação de todas as ameaças sofridas pela árvore na Caatinga.Palavras-chave: Spondias tuberosa, regeneracao natural, conservação, lista vermelha da UICN, Caatinga.

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“…One aspect of the species range expansion and introductions is the ecological meaning of greater rheas as seed predator and seed dispersers [22]. While the species seems strongly restricted to pastures and croplands within the Amazon, never being observed in forests or forest borders, populations in the coastal savannas probably interact extensively with native plant communities, which provide interesting research opportunities.…”

Section: Discussionmentioning

confidence: 99%

“…Feeding mainly on broad-leaved herbs, they occasionally eat fruit and invertebrates [21]. They are seed predators for many plant species in Cerrado, while dispersing seeds in a few cases [22]. They are occasional prey for pumas (Puma concolor), jaguars (Panthera onca) and solitary eagles (Buteogallus coronatus) [23,24], while their eggs serve as food for several armadillo species [25].…”

Section: Introductionmentioning

confidence: 99%

Rhea americana Distribution: Range Expansion and Introductions of America’s Largest Bird

Miranda¹

2021

Birds - Challenges and Opportunities for Business, Conservation and Research

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Species distribution is a good predictor of several important traits, including threat status. Additionally, species expanding out of their original range can become invasive and this trend must be evaluated objectively. The greater rhea (Rhea americana) is a flightless large-sized avian species that thrives on open landscapes of South America. The species has been affected by the conversion of their savanna habitat into cropland and pastures, as well as benefited from forest conversion into fields at neighboring ecoregions. I propose to evaluate those range expansions, contractions and extirpations, as well as to depict the current species distribution. Here I show that greater rheas have expanded their range out of the “dry lands diagonal” into degraded portions of forested ecosystems—more extensively on the Amazon Forest—while persisting in human-altered landscapes of their historical range. This suggests that the species is faring well regarding conservation, which does not justify its current status at IUCN. Additionally, the potential ecological interactions of the species in newly colonized environments must be investigated. The faunal savanization undergoing in the Neotropics accounts on many new ecological interactions, of which greater rheas are a relevant part. Future actions of management may improve the species conservation profile.

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Effect of passage through the gut of Greater Rheas on the germination of seeds of plants of cerrado and caatinga grasslands

Cited by 9 publications

References 32 publications

Changes in Sperm Morphology, Morphometry, and Motility from the Epididymis to the Vas Deferens in Rheas (Rhea americana, Linnaeus, 1758)

Changes in Sperm Morphology, Morphometry, and Motility from the Epididymis to the Vas Deferens in Rheas (Rhea americana, Linnaeus, 1758)

Spondias tuberosa Arruda (Anacardiaceae), a threatened tree of the Brazilian Caatinga?

Rhea americana Distribution: Range Expansion and Introductions of America’s Largest Bird

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