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Understanding of ecosystem structure and functioning requires detailed knowledge about plant–animal interactions, especially when keystone species are involved. The recent consideration of parrots as legitimate seed dispersers has widened the range of mechanisms influencing the life cycle of many plant species. We examined the interactions between the burrowing parrot Cyanoliseus patagonus and two dominant algarrobo trees (Prosopis alba and Prosopis nigra) in the Monte Desert, Argentina. We recorded the abundance and foraging behaviour of parrots; quantified the handling, consumption, wasting, and dispersal of ripe and unripe pods; and tested the viability of soft and hard ripe seeds wasted and transported by parrots. We found a high abundance of burrowing parrots. They predated on soft seeds from unripe pods while exclusively feeding upon pulp wrapping hard seeds from ripe pods. Frequent pod wasting beneath the plant or transport at a distance invariably implied the dispersal of multiple seeds in each event. Moreover, soft seeds retained viability after desiccation outside the mother plant, suggesting effective seed dispersal after partial pod predation due to a predator satiation effect. In about half of the foraging flocks, at least one parrot departed in flight with pods in its beak, with 10–34% of the flock components moving pods at distances averaging 238 m (P. alba) and 418 m (P. nigra). A snapshot sampling of faeces from livestock and wild mammals suggested a low frequency of seed dispersal by endozoochory and secondary dispersal by ants and dung beetles. The nomadic movements and long flights of burrowing parrots between breeding and foraging sites can lead to the dispersal of huge amounts of seeds across large areas that are sequentially exploited. Further research should evaluate the role of the burrowing parrot as a functionally unique species in the structure of the Monte Desert woods and the genetic structure of algarrobo species.
Guillermo Blanco; Pedro Romero-Vidal; Martina Carrete; Daniel Chamorro; Carolina Bravo; Fernando Hiraldo; José Tella. Burrowing Parrots Cyanoliseus patagonus as Long-Distance Seed Dispersers of Keystone Algarrobos, Genus Prosopis, in the Monte Desert. Diversity 2021, 13, 204 .
AMA StyleGuillermo Blanco, Pedro Romero-Vidal, Martina Carrete, Daniel Chamorro, Carolina Bravo, Fernando Hiraldo, José Tella. Burrowing Parrots Cyanoliseus patagonus as Long-Distance Seed Dispersers of Keystone Algarrobos, Genus Prosopis, in the Monte Desert. Diversity. 2021; 13 (5):204.
Chicago/Turabian StyleGuillermo Blanco; Pedro Romero-Vidal; Martina Carrete; Daniel Chamorro; Carolina Bravo; Fernando Hiraldo; José Tella. 2021. "Burrowing Parrots Cyanoliseus patagonus as Long-Distance Seed Dispersers of Keystone Algarrobos, Genus Prosopis, in the Monte Desert." Diversity 13, no. 5: 204.
Nest predation is a major cause of reproductive failure in birds, but predator identity often remains unknown. Additionally, although corvids are considered major nest predators in farmland landscapes, whether breeders or floaters are involved remains contentious. In this study, we aimed to identify nest predators using artificial nests, and test whether territorial or non-breeders carrion crow (Corvus corone) and Eurasian magpie (Pica pica) were most likely involved. We set up an experiment with artificial ground nests (n = 1429) in farmland landscapes of western France, and assessed how different combinations of egg size and egg material (small plasticine egg, large plasticine egg, quail and natural hen eggs) might influence predation rates and predator species involved. Nest predators were identified using remotely triggered cameras and marks left in plasticine eggs. Corvids were by far the predators most involved (almost 80% of all predation events), independent of egg type. Carrion crows alone were involved in 60% of cases. Probability of predation increased with egg size, and predation rate was higher for natural than for artificial eggs, suggesting that, in addition to egg size, predators might perceive plasticine and natural eggs differently. Predation rates of artificial nests by corvids were related significantly to corvid abundance, and far more to breeder than floater abundances, for both carrion crows and magpies. This study emphasizes the importance of identifying predators at species level, and considering their social status when assessing corvid abundance impact on prey population dynamics. Combining camera traps and plasticine eggs can achieve this objective. Given the high predation rate by carrion crows, a better understanding of landscape-mediated changes in predator diet seems mandatory to design mitigation schemes able to confront ecological challenges raised by generalist predators.
Carolina Bravo; Olivier Pays; Mathieu Sarasa; Vincent Bretagnolle. Revisiting an old question: Which predators eat eggs of ground-nesting birds in farmland landscapes? Science of The Total Environment 2020, 744, 140895 .
AMA StyleCarolina Bravo, Olivier Pays, Mathieu Sarasa, Vincent Bretagnolle. Revisiting an old question: Which predators eat eggs of ground-nesting birds in farmland landscapes? Science of The Total Environment. 2020; 744 ():140895.
Chicago/Turabian StyleCarolina Bravo; Olivier Pays; Mathieu Sarasa; Vincent Bretagnolle. 2020. "Revisiting an old question: Which predators eat eggs of ground-nesting birds in farmland landscapes?" Science of The Total Environment 744, no. : 140895.
Aims Seed dispersal by endozoochory is an important process in plant regeneration and the establishment of new populations. Seeds with dormancy may especially benefit after disperser gut passage. However, the ways in which gut passage affect the germination of plant species with physiological dormancy remain unclear. Here, we experimentally assessed the mutualistic interaction between the Austral parakeet (Enicognathus ferrugineus) as a disperser of calafate (Berberis microphylla), a thorny bush inhabiting the understory of the Austral temperate forests of South America with seeds that are characterized by deep physiological dormancy. Methods Germination success and viability of calafate seeds obtained from faeces and from intact fruits were tested under four treatments: (i) digested seeds, (ii) digested seeds with faecal extract, (iii) intact seeds from fruit and (iv) intact seeds from fruit with pulp. Important Findings About 65% of the Austral parakeet droppings contained calafate seeds. Viability of seeds did not differ between treatments. However, germination was significantly higher in digested seeds than in intact seeds from fruits, while no difference was found between faecal and pulp extracts. Neither faecal matter nor fruit pulp provided seeds with any ecological advantages derived from enhancing germinability, but did confer some disadvantage in germination time. Faecal matter is expected to be completely lacking around seeds after several months under snow before germinating in the following spring, given intense washing due to persistent rain and the spring thaw in the Patagonian Andes. The higher germinability along with faster germination of digested seeds supports the hypothesis of a legitimate mutualistic interaction between Austral parakeets and calafate. We hypothesized that the passage through the disperser digestive tract might break physiological dormancy as differences in germinability between ingested and non-ingested seeds. Our results highlight the relevant role of endozoochory in plant species with physiological dormancy living in highly seasonal environments.
Carolina Bravo; Daniel Chamorro; Fernando Hiraldo; Karina Speziale; Sergio A Lambertucci; José L Tella; Guillermo Blanco. Physiological dormancy broken by endozoochory: Austral parakeets (Enicognathus ferrugineus) as legitimate dispersers of calafate (Berberis microphylla) in the Patagonian Andes. Journal of Plant Ecology 2020, 13, 538 -544.
AMA StyleCarolina Bravo, Daniel Chamorro, Fernando Hiraldo, Karina Speziale, Sergio A Lambertucci, José L Tella, Guillermo Blanco. Physiological dormancy broken by endozoochory: Austral parakeets (Enicognathus ferrugineus) as legitimate dispersers of calafate (Berberis microphylla) in the Patagonian Andes. Journal of Plant Ecology. 2020; 13 (5):538-544.
Chicago/Turabian StyleCarolina Bravo; Daniel Chamorro; Fernando Hiraldo; Karina Speziale; Sergio A Lambertucci; José L Tella; Guillermo Blanco. 2020. "Physiological dormancy broken by endozoochory: Austral parakeets (Enicognathus ferrugineus) as legitimate dispersers of calafate (Berberis microphylla) in the Patagonian Andes." Journal of Plant Ecology 13, no. 5: 538-544.
How animals use food resources according to their relative availability is essential for our understanding and predictions of ecosystem interaction. Non-linear functions between use and availability are described with the feeding functional response, a key tool to describe such functions that is still poorly understood in some cases. For example, in species with a marked sexual size dimorphism it is not clear how such non-linear functions differ between males and females. Here, we used likelihood methods and model selection to model non-linear functions in legume use by male and female great bustards (Otis tarda) based on diet composition data from droppings. The great bustard shows the highest sexual size dimorphism among birds, and it has opportunistic and generalist foraging habits, with a strong selection for legumes. Simple functional-response models described the proportion of legumes in great bustard droppings as a non-linear function of legume availability. Functional response type II fitted to data better than type III in autumn and winter, whereas in spring, type III was the best-fitted model, describing a dietary switch of great bustards feeding on legumes. The best-fitted functional response included an effect of sex in the asymptote of the curve; the female diet included a higher proportion of legumes than the male diet, suggesting a possible effect of sexual size dimorphism. We concluded that great bustards behaved as opportunistic foragers, whose sexual size dimorphism might play a role in the functional response to legumes.
Carolina Bravo; Luis M. Bautista; Carlos Ponce; Juan C. Alonso. Feeding functional responses in a sexually size-dimorphic bird. Acta Oecologica 2019, 101, 103487 .
AMA StyleCarolina Bravo, Luis M. Bautista, Carlos Ponce, Juan C. Alonso. Feeding functional responses in a sexually size-dimorphic bird. Acta Oecologica. 2019; 101 ():103487.
Chicago/Turabian StyleCarolina Bravo; Luis M. Bautista; Carlos Ponce; Juan C. Alonso. 2019. "Feeding functional responses in a sexually size-dimorphic bird." Acta Oecologica 101, no. : 103487.
Increase in nest predation has been identified as a major cause of decline of farmland birds. However, the interactions between agricultural intensification and predation are still poorly understood, particularly after the introduction of agri-environmental schemes (AES). We used an artificial nest predation experiment and camera trapping to examine how AES measures (vetch, organic cereal, and long-term fallows) can affect nest predation in a dry cereal farmland area in central Spain. We found that 66% of nests were predated, and 6% were run over by tractors during the traditional spring works to eliminate weeds in plowed fields. Nests surrounded by tall vegetation suffered lower predation rates, cereal crops being the safest substrate. In contrast, the highest predation rate was found in plowed fields, where nests were more exposed and vulnerable. Nest predation was higher near field edges, where mammals concentrate their predation effort, as shown by camera trapping. Predation was also high in long-term fallows and organic cereal crops, where prey are more abundant than in other field types, thus attracting predators. This was confirmed by the higher mammal predation events recorded by wildlife cameras in fallow fields compared to other substrates. To minimize this predation increase, we recommend that AES-promoted fields should be dispersed, in order to prevent an accumulation of high-quality patches which might attract predators. Finally, it is crucial to establish some restrictions on tractor works in plowed fields in spring to decrease the remarkably high rate of nest destruction (one of every four nests in this substrate).
Carlos Ponce; Iván Salgado; Carolina Bravo; Natalia Gutiérrez; Juan Carlos Alonso. Effects of farming practices on nesting success of steppe birds in dry cereal farmland. European Journal of Wildlife Research 2018, 64, 13 .
AMA StyleCarlos Ponce, Iván Salgado, Carolina Bravo, Natalia Gutiérrez, Juan Carlos Alonso. Effects of farming practices on nesting success of steppe birds in dry cereal farmland. European Journal of Wildlife Research. 2018; 64 (2):13.
Chicago/Turabian StyleCarlos Ponce; Iván Salgado; Carolina Bravo; Natalia Gutiérrez; Juan Carlos Alonso. 2018. "Effects of farming practices on nesting success of steppe birds in dry cereal farmland." European Journal of Wildlife Research 64, no. 2: 13.
. Sexual size dimorphism (SSD) may favour physiological peculiarities in diet, behaviour and home-range size both across species and within species. Sex-specific differences in diet and behaviour have been reported in several bird species but there are fewer studies of foraging area size in sexually dimorphic bird species. Foraging area size should be greater in the bigger sex according to home-range size predictions based on body mass. We tested this prediction in a winter study of foraging area size in the Great Bustard Otis tarda, the most sexually size-dimorphic bird species, which forages in unisexual flocks. In this species the temporal pattern of a flock's feeding intensity; the proportion of birds actively feeding (FI) and the size of the morning foraging area (MFA) of each sex are unknown. We recorded the behaviour and movements of unisexual flocks of Great Bustards during winter mornings and sampled food availability to take into account its effect on FI and MFA. FI increased and then decreased through the morning in both sexes, and was lower in males than in females. This sexual difference was greater where legume availability was smaller. Legumes were the most preferred substrate type. Consequently, MFA sizes were smaller in sites with more legume availability. We did not find sexual differences either in the size of MFA or in the selection of the two preferred substrate types: legumes and stubble fields. MFA and FI were determined to a greater extent by ecological factors such as food availability than by metabolic requirements derived from body size differences. These results obtained from a short-term study do not preclude an effect of sexual size dimorphism on MFA size and FI of Great Bustards over longer periods but show that the body size effect on foraging behaviour may be smaller than predicted only by SSD. Resumen. El dimorfismo sexual en tamaño (SSD) puede favorecer particularidades fisiológicas en la dieta, el comportamiento y el tamaño del área de campeo tanto entre especies como dentro de especies. Se han encontrado diferencias específicas en la dieta y el comportamiento en distintas especies de aves, pero hay pocos estudios sobre el área de aprovisionamiento en especies sexualmente dimórficas. El tamaño del área de aprovisionamiento debería ser mayor en el sexo más grande, de acuerdo a las predicciones sobre el área de campeo basadas en el tamaño corporal. En este trabajo comprobamos esta predicción en un estudio invernal del tamaño del área de aprovisionamiento en la avutarda euroasiática Otis tarda, la especie de ave con el dimorfismo sexual en tamaño más acusado y que forrajea en bandos unisexuales. En esta especie se desconoce el patrón temporal de alimentación de los bandos, la proporción de aves que están alimentándose activamente (FI) y el tamaño del área de forrajeo matutina (MFA) de cada sexo. Registramos el comportamiento y los movimientos de bandos unisexuales de avutardas durante mañanas invernales y muestreamos la disponibilidad de alimento para tener en cuenta su efecto en FI y MFA. El FI aumentó y después decreció durante la mañana en ambos sexos, fue más bajo en los machos que en las hembras. Esta diferencia sexual fue mayor donde la disponibilidad de leguminosas era más baja. Los campos de leguminosas fueron el sustrato preferido. En consecuencia, el tamaño de MFA fue más pequeño en los sitios con mayor disponibilidad de leguminosas. No encontramos diferencias sexuales ni en el tamaño del MFA ni en la selección de los dos sustratos preferidos: leguminosas y barbechos. El MFA y el FI fueron determinados más por factores ecológicos como la disponibilidad de alimento que por los requerimientos metabólicos derivados de las diferencias en el tamaño. Estos resultados obtenidos de un estudio a corto plazo no excluyen un efecto del dimorfismo sexual en tamaño sobre los tamaños de MFA y FI de las avutardas en periodos de tiempo más prolongados, pero muestran que el efecto del tamaño corporal en el comportamiento de forrajeo puede ser más pequeño que lo que se predice solamente por el SSD.
Luis M. Bautista; Carolina Bravo; Carlos Ponce; Dácil Unzué-Belmonte; Juan Carlos Alonso. Food Availability But Not Sex Determines Morning Foraging Area Size in the Great Bustard Otis tarda, the Most Sexually Size-Dimorphic Bird Species. Ardeola 2017, 64, 289 -303.
AMA StyleLuis M. Bautista, Carolina Bravo, Carlos Ponce, Dácil Unzué-Belmonte, Juan Carlos Alonso. Food Availability But Not Sex Determines Morning Foraging Area Size in the Great Bustard Otis tarda, the Most Sexually Size-Dimorphic Bird Species. Ardeola. 2017; 64 (2):289-303.
Chicago/Turabian StyleLuis M. Bautista; Carolina Bravo; Carlos Ponce; Dácil Unzué-Belmonte; Juan Carlos Alonso. 2017. "Food Availability But Not Sex Determines Morning Foraging Area Size in the Great Bustard Otis tarda, the Most Sexually Size-Dimorphic Bird Species." Ardeola 64, no. 2: 289-303.
Intra-specific coloration polymorphism coupled with an ancient process of lineage differentiation in Berberomeloe majalis (Linnaeus, 1758) offers the opportunity to analyse the temporal scenario in which the correlation between toxicity and coloration might have evolved. Based on phylogenetic and phylogeographic analyses, we identified the timing for the split between red-striped and entirely black morphotypes of B. majalis. To evaluate whether coloration patterns and toxicity are related in this species, we quantified the concentration of cantharidin across morphotypes and phylogeographic lineages. Phylogenetic analyses based on cox1 mitochondrial DNA sequences recovered three major clades where both morphotypes were intermingled, indicating a multiple homoplastic origin for the entirely black coloration. Our analyses showed that cantharidin content did not differ between morphs of B. majalis; however, it significantly increased in haemolymph in females kept isolated from males, which reveals the females’ ability either to concentrate cantharidin towards haemolymph or to synthesize cantharidin themselves. Lack of monophyly and absence of genetic isolation in both morphotypes favour the hypothesis of a recent homoplastic phenomenon to explain the loss of the striped pattern. Our phylogenetic and phylogeographic analyses show that changes in coloration are recent, suggesting that the ancient pressures that fixed and maintained red-striped colorations are no longer acting today on B. majalis. The absence of change in cantharidin content (i.e. entirely black and red-striped specimens are equally poisonous) suggests that the evolution of colour polymorphisms in B. majalis is probably decoupled from toxicity.
Carolina Bravo; Paloma Mas-Peinado; Luis Miguel Bautista; Guillermo Blanco; Juan Carlos Alonso; Mario García-París. Cantharidin is conserved across phylogeographic lineages and present in both morphs of Iberian Berberomeloe blister beetles (Coleoptera, Meloidae). Zoological Journal of the Linnean Society 2017, 180, 790 -804.
AMA StyleCarolina Bravo, Paloma Mas-Peinado, Luis Miguel Bautista, Guillermo Blanco, Juan Carlos Alonso, Mario García-París. Cantharidin is conserved across phylogeographic lineages and present in both morphs of Iberian Berberomeloe blister beetles (Coleoptera, Meloidae). Zoological Journal of the Linnean Society. 2017; 180 (4):790-804.
Chicago/Turabian StyleCarolina Bravo; Paloma Mas-Peinado; Luis Miguel Bautista; Guillermo Blanco; Juan Carlos Alonso; Mario García-París. 2017. "Cantharidin is conserved across phylogeographic lineages and present in both morphs of Iberian Berberomeloe blister beetles (Coleoptera, Meloidae)." Zoological Journal of the Linnean Society 180, no. 4: 790-804.
Bravo, C., F. Cuscó, M. Borja Morales, and S. Mañosa. 2017. Diet composition of a declining steppe bird the Little Bustard (Tetrax tetrax) in relation to farming practices. Avian Conservation and Ecology 12(1):3. https://doi.org/10.5751/ACE-00938-120103
Carolina Bravo; Francesc Cuscó; Manuel B. Morales; Santi Mañosa. Diet composition of a declining steppe bird the Little Bustard (Tetrax tetrax) in relation to farming practices. Avian Conservation and Ecology 2017, 12, 1 .
AMA StyleCarolina Bravo, Francesc Cuscó, Manuel B. Morales, Santi Mañosa. Diet composition of a declining steppe bird the Little Bustard (Tetrax tetrax) in relation to farming practices. Avian Conservation and Ecology. 2017; 12 (1):1.
Chicago/Turabian StyleCarolina Bravo; Francesc Cuscó; Manuel B. Morales; Santi Mañosa. 2017. "Diet composition of a declining steppe bird the Little Bustard (Tetrax tetrax) in relation to farming practices." Avian Conservation and Ecology 12, no. 1: 1.
RESUMEN En las especies con dimorfismo sexual de tamaño, las limitaciones fisiológicas derivadas de las diferencias en el tamaño corporal pueden determinar diferentes requerimientos alimentarios y por ende una divergencia del nicho trófico entre los machos y las hembras. Estas relaciones entre el dimorfismo sexual de tamaño corporal (DST) y el solapamiento de la dieta no están bien entendidas en las aves. Analizamos las diferencias sexuales en la composición de la dieta, la diversidad de la dieta, la selección de la dieta, y el volumen y la densidad de las heces, así como el solapamiento de la dieta entre sexos en Otis tarda, la especie con mayor DST entre las aves. Las diferencias encontradas fueron analizadas con relación a varias predicciones derivadas de las diferencias ecológicas y fisiológicas entre los sexos, bajo la hipótesis de que estas diferencias están determinadas en última instancia por el fuerte DST en esta especie. Como esperábamos, nuestros mejores modelos lineales de efectos mixtos de selección de alimentos incluyeron al sexo como el factor principal que explica las diferencias en la composición y en la diversidad de la dieta en O. tarda a lo largo del ciclo anual. Ambos sexos fueron principalmente herbívoros, consumiendo legumbres cuando estaban disponibles. Los machos consumieron menos artrópodos pero de tamaño significativamente más grande que las hembras. Las heces de los machos fueron de mayor tamaño y más pesadas, y levemente más densas que las de las hembras. Los machos mostraron una mayor diversidad en la dieta que las hembras, excepto durante la estación post reproductiva. El solapamiento promedio de la dieta entre los sexos fue 0.7, uno de los valores más pequeños entre las aves. En conjunto, nuestros resultados sugieren que el enorme DST en esta especie, junto con el rol reproductivo distintivo de cada sexo, podrían explicar la divergencia del nicho trófico en O. tarda. Palabras clave: agro-estepa, comportamiento trófico, ecología de forrajeo, herbivoría, partición del recurso, segregación sexual, solapamiento de la dieta, tamaño corporal
Carolina Bravo; Carlos Ponce; Luis M. Bautista; Juan C. Alonso. Dietary divergence in the most sexually size-dimorphic bird. Ornithology 2016, 133, 178 -197.
AMA StyleCarolina Bravo, Carlos Ponce, Luis M. Bautista, Juan C. Alonso. Dietary divergence in the most sexually size-dimorphic bird. Ornithology. 2016; 133 (2):178-197.
Chicago/Turabian StyleCarolina Bravo; Carlos Ponce; Luis M. Bautista; Juan C. Alonso. 2016. "Dietary divergence in the most sexually size-dimorphic bird." Ornithology 133, no. 2: 178-197.
Despite the fact that parrots (Psitacifformes) are generalist apex frugivores, they have largely been considered plant antagonists and thus neglected as seed dispersers of their food plants. Internal dispersal was investigated by searching for seeds in faeces opportunistically collected at communal roosts, foraging sites and nests of eleven parrot species in different habitats and biomes in the Neotropics. Multiple intact seeds of seven plant species of five families were found in a variable proportion of faeces from four parrot species. The mean number of seeds of each plant species per dropping ranged between one and about sixty, with a maximum of almost five hundred seeds from the cactiPilosocereus pachycladusin a single dropping of Lear’s Macaw (Anodorhynchus leari). All seeds retrieved were small (
Guillermo Blanco; Carolina Bravo; Erica C. Pacifico; Daniel Chamorro; Karina L. Speziale; Sergio Lambertucci; Fernando Hiraldo; José L. Tella. Internal seed dispersal by parrots: an overview of a neglected mutualism. PeerJ 2016, 4, e1688 .
AMA StyleGuillermo Blanco, Carolina Bravo, Erica C. Pacifico, Daniel Chamorro, Karina L. Speziale, Sergio Lambertucci, Fernando Hiraldo, José L. Tella. Internal seed dispersal by parrots: an overview of a neglected mutualism. PeerJ. 2016; 4 ():e1688.
Chicago/Turabian StyleGuillermo Blanco; Carolina Bravo; Erica C. Pacifico; Daniel Chamorro; Karina L. Speziale; Sergio Lambertucci; Fernando Hiraldo; José L. Tella. 2016. "Internal seed dispersal by parrots: an overview of a neglected mutualism." PeerJ 4, no. : e1688.
We present evidence of a possible case of self-medication in a lekking bird, the great bustard Otis tarda. Great bustards consumed blister beetles (Meloidae), in spite of the fact that they contain cantharidin, a highly toxic compound that is lethal in moderate doses. In addition to anthelminthic properties, cantharidin was effective against gastrointestinal bacteria that cause sexually-transmitted diseases. Although both sexes consumed blister beetles during the mating season, only males selected them among all available insects, and ingested more and larger beetles than females. The male-biased consumption suggests that males could use cantharidin to reduce their parasite load and increase their sexual attractiveness. This plausibly explains the intense cloaca display males perform to approaching females, and the meticulous inspection females conduct of the male's cloaca, a behaviour only observed in this and another similar species of the bustard family. A white, clean cloaca with no infection symptoms (e.g., diarrhoea) is an honest signal of both, resistance to cantharidin and absence of parasites, and represents a reliable indicator of the male quality to the extremely choosy females. Our results do not definitely prove, but certainly strongly suggest that cantharidin, obtained by consumption of blister beetles, acts in great bustards as an oral anti-microbial and pathogen-limiting compound, and that males ingest these poisonous insects to increase their mating success, pointing out that self-medication might have been overlooked as a sexually-selected mechanism enhancing male fitness.
Carolina Bravo; Luis M. Bautista; Mario García-París; Guillermo Blanco; Juan Carlos Alonso. Males of a Strongly Polygynous Species Consume More Poisonous Food than Females. PLOS ONE 2014, 9, e111057 .
AMA StyleCarolina Bravo, Luis M. Bautista, Mario García-París, Guillermo Blanco, Juan Carlos Alonso. Males of a Strongly Polygynous Species Consume More Poisonous Food than Females. PLOS ONE. 2014; 9 (10):e111057.
Chicago/Turabian StyleCarolina Bravo; Luis M. Bautista; Mario García-París; Guillermo Blanco; Juan Carlos Alonso. 2014. "Males of a Strongly Polygynous Species Consume More Poisonous Food than Females." PLOS ONE 9, no. 10: e111057.
Studies evaluating agri‐environmental schemes (AES) usually focus on responses of single species or functional groups. Analyses are generally based on simple habitat measurements but ignore food availability and other important factors. This can limit our understanding of the ultimate causes determining the reactions of birds to AES. We investigated these issues in detail and throughout the main seasons of a bird's annual cycle (mating, postfledging and wintering) in a dry cereal farmland in a Special Protection Area for farmland birds in central Spain. First, we modeled four bird response parameters (abundance, species richness, diversity and “Species of European Conservation Concern” [SPEC]‐score), using detailed food availability and vegetation structure measurements (food models). Second, we fitted new models, built using only substrate composition variables (habitat models). Whereas habitat models revealed that both, fields included and not included in the AES benefited birds, food models went a step further and included seed and arthropod biomass as important predictors, respectively, in winter and during the postfledging season. The validation process showed that food models were on average 13% better (up to 20% in some variables) in predicting bird responses. However, the cost of obtaining data for food models was five times higher than for habitat models. This novel approach highlighted the importance of food availability‐related causal processes involved in bird responses to AES, which remained undetected when using conventional substrate composition assessment models. Despite their higher costs, measurements of food availability add important details to interpret the reactions of the bird community to AES interventions and thus facilitate evaluating the real efficiency of AES programs.
Carlos Ponce; Carolina Bravo; Juan Carlos Alonso. Effects of agri‐environmental schemes on farmland birds: do food availability measurements improve patterns obtained from simple habitat models? Ecology and Evolution 2014, 4, 2834 -2847.
AMA StyleCarlos Ponce, Carolina Bravo, Juan Carlos Alonso. Effects of agri‐environmental schemes on farmland birds: do food availability measurements improve patterns obtained from simple habitat models? Ecology and Evolution. 2014; 4 (14):2834-2847.
Chicago/Turabian StyleCarlos Ponce; Carolina Bravo; Juan Carlos Alonso. 2014. "Effects of agri‐environmental schemes on farmland birds: do food availability measurements improve patterns obtained from simple habitat models?" Ecology and Evolution 4, no. 14: 2834-2847.
Predictive species’ distribution models may answer ecological questions about habitat selection, co-occurrence of species and competition between them. We studied the habitat preferences and segregation of two sympatric species of declining sandgrouse, the black-bellied sandgrouse (Pterocles orientalis) and the pin-tailed sandgrouse (Pterocles alchata), during the breeding season. We developed predictive models that related sandgrouse presence to environmental variables at three different spatial levels: large geographical, landscape and microhabitat scales. At the large geographical scale, differences between sandgrouse distributions, in the Iberian Peninsula, seem to be explained mainly in terms of bioclimatology: pin-tailed sandgrouse appear to be a more thermophilous species and occupy warmer sites usually located in flatter areas. At the landscape spatial level, in those areas that exhibit environmental conditions allowing for both species’ co-existence at a large geographical scale, black-bellied sandgrouse appear to be more tolerant to environmental variation than pin-tailed sandgrouse. At the microhabitat level, however, differences between species could be related to different flocking behaviour as a consequence of different sensitivities to vegetation structure and predators. Thus, the observed spatial distribution patterns are the result of different ecological factors that operate at different spatial levels. Conservation guidelines for these species should therefore consider their habitat preferences at large geographical, landscape and microhabitat scales.
Beatriz Martín; Carlos A. Martín; Carlos Palacín; Pablo Sastre; Carlos Ponce; Carolina Bravo. Habitat preferences of sympatric sandgrouse during the breeding season in Spain: a multi-scale approach. European Journal of Wildlife Research 2014, 60, 625 -636.
AMA StyleBeatriz Martín, Carlos A. Martín, Carlos Palacín, Pablo Sastre, Carlos Ponce, Carolina Bravo. Habitat preferences of sympatric sandgrouse during the breeding season in Spain: a multi-scale approach. European Journal of Wildlife Research. 2014; 60 (4):625-636.
Chicago/Turabian StyleBeatriz Martín; Carlos A. Martín; Carlos Palacín; Pablo Sastre; Carlos Ponce; Carolina Bravo. 2014. "Habitat preferences of sympatric sandgrouse during the breeding season in Spain: a multi-scale approach." European Journal of Wildlife Research 60, no. 4: 625-636.
Faecal sexual steroids have been used in field studies evaluating the relationships between gender and the multiple factors influencing endocrine status of individuals. The determination of faecal steroids has been also proposed as an alternative, non-invasive sexing method when other methods were deemed impractical or risky for the health of birds. In this study, we quantified sexual steroid hormones in faeces of the great bustard (Otis tarda), a large and sexually dimorphic polyginic bird species that it is threatened and subjected to intense wildlife management. We evaluated differences between captivity and wild conditions, flocks and sexes, and used faecal steroids to develop sex determination procedures. We found similar steroid levels in captive and wild bustards, no differences between unisexual wild flocks and clear between-sexes differences in testosterone but not estradiol. Faecal steroids accurately discriminated gender in both captive and wild known-sex great bustards. Total testosterone concentration was always higher than estradiol concentration in faecal samples from males, but estradiol was not always higher than testosterone in females. Faecal steroids failed to reveal the presence of young males in female flocks during winter, despite faecal testosterone levels increased with age in a small sample of captive males. Our results show that faecal steroid measurement for both sexing and characterizing the endocrine status of great bustards is feasible, and therefore it should be valuable in wildlife management, especially in combination with additional information obtained from faeces as diet.
Luis M. Bautista; Gema Silván; Sara Cáceres; Leticia Martínez-Fernández; Carolina Bravo; Juan C. Illera; Juan Carlos Alonso; Guillermo Blanco. Faecal sexual steroids in sex typing and endocrine status of great bustards. European Journal of Wildlife Research 2013, 59, 815 -822.
AMA StyleLuis M. Bautista, Gema Silván, Sara Cáceres, Leticia Martínez-Fernández, Carolina Bravo, Juan C. Illera, Juan Carlos Alonso, Guillermo Blanco. Faecal sexual steroids in sex typing and endocrine status of great bustards. European Journal of Wildlife Research. 2013; 59 (6):815-822.
Chicago/Turabian StyleLuis M. Bautista; Gema Silván; Sara Cáceres; Leticia Martínez-Fernández; Carolina Bravo; Juan C. Illera; Juan Carlos Alonso; Guillermo Blanco. 2013. "Faecal sexual steroids in sex typing and endocrine status of great bustards." European Journal of Wildlife Research 59, no. 6: 815-822.
Capsule Arthropods are the most important diet component of Great Bustards Otis tarda in the first months of life. Aims To determine the diet composition of young Great Bustards in Spain. Methods The diet was estimated by stomach content analysis (n = 49). Results Stomach contents' dry weight consisted of 33% arthropods, 30% green plant material and 23% seeds. Gastroliths were only found in summer and autumn. The diet composition changed significantly between seasons. In summer, diet consisted mainly of arthropods (50%), with green plant material being the main component in winter (56%). Volume of stomach contents and mean size of ingested arthropods were higher in males than in females. Diet composition did not differ between sexes. In summer, ground-dwelling and plant-visiting arthropods such as Mantidae, Tenebrionidae and caterpillars were the most abundant. In winter, weeds, legumes and cultivated seeds were more frequent than arthropods. Cereal plants were the least consumed in all seasons, although Barley and Wheat seeds played an important role during winter and autumn. Conclusion The results highlight the importance of arthropods and weeds as a fundamental component of the diet of young Great Bustards. Because previous studies show that arthropods and weeds are usually more abundant in extensive farming, we recommend the implementation of agri-environmental measures in Great Bustard breeding areas.
Carolina Bravo; Carlos Ponce; Carlos Palacín; Juan Carlos Alonso. Diet of young Great Bustards Otis tarda in Spain: sexual and seasonal differences. Bird Study 2012, 59, 243 -251.
AMA StyleCarolina Bravo, Carlos Ponce, Carlos Palacín, Juan Carlos Alonso. Diet of young Great Bustards Otis tarda in Spain: sexual and seasonal differences. Bird Study. 2012; 59 (2):243-251.
Chicago/Turabian StyleCarolina Bravo; Carlos Ponce; Carlos Palacín; Juan Carlos Alonso. 2012. "Diet of young Great Bustards Otis tarda in Spain: sexual and seasonal differences." Bird Study 59, no. 2: 243-251.
7 paginas, 3 figuras y 1 tableFor many years anticoagulant rodenticides have been used in vole control campaigns, in spite of the proven risk of secondary poisoning of non-target predators and scavengers. In this paper we analyse for the first time great bustard exposure and intoxication by anticoagulant rodenticides in Spain, based on residues found in\ud the livers of 71 bustard carcasses collected during 1991–2010. Ten individuals contained chlorophacinone and one flocoumafen. Chlorophacinone level was significantly correlated with the pathogen and parasite burden of intoxicated birds. Moreover, through the last 12 years the annual number of great bustards that present chlorophacinone in liver collected in our study areas was correlated with vole peaks at a nearby area, suggesting that the ingestion of rodenticide was proportional to the amounts spread in the fields. We\ud conclude that rodenticide consumption is a regular event among great bustards when baited cereal is spread on fields, and that this may cause chronic weakening of intoxicated individuals, possibly affecting their survival. Future rodent control actions should consider these negative side effects on non target granivorous steppe and farmland species, particularly when they are globally threatened.Financial support was provided by project CGL2008-02567 of the Dirección General de Investigación, Spanish Ministry for Science and\ud InnovationPeer reviewe
J.A. Lemus; Carolina Bravo; M. García-Montijano; Carlos Palacín; C. Ponce; M. Magaña; Juan Carlos Alonso. Side effects of rodent control on non-target species: Rodenticides increase parasite and pathogen burden in great bustards. Science of The Total Environment 2011, 409, 4729 -4734.
AMA StyleJ.A. Lemus, Carolina Bravo, M. García-Montijano, Carlos Palacín, C. Ponce, M. Magaña, Juan Carlos Alonso. Side effects of rodent control on non-target species: Rodenticides increase parasite and pathogen burden in great bustards. Science of The Total Environment. 2011; 409 (22):4729-4734.
Chicago/Turabian StyleJ.A. Lemus; Carolina Bravo; M. García-Montijano; Carlos Palacín; C. Ponce; M. Magaña; Juan Carlos Alonso. 2011. "Side effects of rodent control on non-target species: Rodenticides increase parasite and pathogen burden in great bustards." Science of The Total Environment 409, no. 22: 4729-4734.
Organic farming is considered an important way to preserve biodiversity in agricultural landscapes. However, more work is still necessary to enable a full appraisal of the potential benefits of this way of farming, since studies differ in the evaluation of its effectiveness. Studies are particularly scarce in the Mediterranean region, where different climatic and ecological conditions prevent simple extrapolations from work carried out at northern latitudes. In the present study, an analysis of weed and arthropod communities was conducted in 28 pairs of organic and conventional fields in a dry cereal farmland in central Spain. Plants were identified to the species level, and arthropods to the family level. Pitfalls and sweep nets were used to sample respectively, ground-dwelling and plant-visiting arthropods. Abundance (total numbers of individuals), richness (total numbers of plant species or arthropod families), diversity (Shannon–Wiener index) and biomass (milligrams per pitfall/sweep-net) were calculated for each field and compared between organic and conventional fields using Generalized Linear Mixed Models (GLMMs). To explore the effect of predictor variables on weed richness and arthropod biomass, GLMMs were used. Organic fields showed higher abundance of weeds and arthropods (3.01 and 1.43 times, respectively), higher weed richness and diversity (2.76 and 2.33 times, respectively), and a 24% reduction in cereal plants. Arthropod diversity was lower in organic fields due to the presence of three dominant groups: Collembola, Chloropidae (Diptera), and Aphididae (Hemiptera). Weed richness increased as cereal cover decreased in organic fields. Total arthropod biomass was slightly higher in organic fields, and was affected by weed abundance and diversity. The differences between organic and conventional fields found in this study were higher than those reported for northern latitudes. This could be explained by the richer weed flora in the Mediterranean region, and a higher weed seed availability favored by the two-year rotation system typical of Iberian dry cereal farmland. We conclude that organic farming may contribute to preserve biodiversity in dryland cereal agroecosystems in the Mediterranean region.
Carlos Ponce; Carolina Bravo; David García de León; Marina Magaña; Juan Carlos Alonso. Effects of organic farming on plant and arthropod communities: A case study in Mediterranean dryland cereal. Agriculture, Ecosystems & Environment 2011, 141, 193 -201.
AMA StyleCarlos Ponce, Carolina Bravo, David García de León, Marina Magaña, Juan Carlos Alonso. Effects of organic farming on plant and arthropod communities: A case study in Mediterranean dryland cereal. Agriculture, Ecosystems & Environment. 2011; 141 (1-2):193-201.
Chicago/Turabian StyleCarlos Ponce; Carolina Bravo; David García de León; Marina Magaña; Juan Carlos Alonso. 2011. "Effects of organic farming on plant and arthropod communities: A case study in Mediterranean dryland cereal." Agriculture, Ecosystems & Environment 141, no. 1-2: 193-201.