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Martínez-Abraín A, Santidrián Tomillo P, Veiga J. Otter diet changes in a reservoir during a severe autumn drought. J Mammal 2019. [DOI: 10.1093/jmammal/gyz185] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Eurasian otters (Lutra lutra) are known to make extensive use of reservoirs in the Iberian Peninsula, where they forage preferentially on small-size fish (10–20 cm). We hypothesized that the usual consumption of small-size fish by otters in reservoirs is not due to prey size preference, but rather to a higher level of difficulty in capturing larger prey. We studied otter diet in a reservoir that experienced an abrupt drop in stored water caused by an unusually severe drought. We compared relative prey size, hunting success, and diving times between the year of the drought (2017) and two standard rainfall years (2015 and 2016). Otters ate a similar proportion of small and large fish during the drought instead of predominantly eating small fish. Mean diving time during the drought was similar to that of the standard climatic years, indicating a similar physiological cost of capture between small and large fish. Otters had higher hunting success in the drought year (89%) than in the standard years (63%) regardless of prey size. This suggests a higher level of catchability of both fish size classes during the drought as the water level was lower. Results suggest that the usual consumption of small-sized fish by otters in reservoirs could not be related to preference or relative abundance but rather to the difficulty of capturing large-size fish when water levels are high.
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Affiliation(s)
- Alejandro Martínez-Abraín
- Department of Biology, Evolutionary Biology Research Group (GIBE), Universidade da Coruña, Campus da Zapateira, A Coruña, Spain
| | | | - Juan Veiga
- Calle Río Barcés 8, Cambre, A Coruña, Spain
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Llinares Á, Martínez-Abraín A, Veiga J. High foraging efficiency of Eurasian otters in a shallow Iberian reservoir. WILDLIFE BIOLOGY 2019. [DOI: 10.2981/wlb.00589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Ánxela Llinares
- Á. Llinares and A. Martínez-Abraín (https://orcid.org/0000-0001-8009-4331) ✉ , Dept of Biology, Evolutionary Biology Research Group (GIBE), Univ. da Coruña, Campus da Zapateira, ES-15008 A Coruña, Spain
| | - Alejandro Martínez-Abraín
- Á. Llinares and A. Martínez-Abraín (https://orcid.org/0000-0001-8009-4331) ✉ , Dept of Biology, Evolutionary Biology Research Group (GIBE), Univ. da Coruña, Campus da Zapateira, ES-15008 A Coruña, Spain
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Hong S, Gim JS, Kim HG, Cowan PE, Joo GJ. A molecular approach to identifying the relationship between resource use and availability in Eurasian otters (Lutra lutra). CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0289] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In South Korea, the Eurasian otter (Lutra lutra (Linnaeus, 1758)), a semi-aquatic carnivore, is found mainly in lower order streams that tend to have a low abundance of preferred prey fish species. To investigate the relationship between resource use and availability, we used DNA barcoding to identify otter diet items in 24 otter spraints (faeces) from 16 sites along the Nakdong River basin from 4 to 6 June 2014. At these sites fish availability was assessed using scoop nets and casting nets. Fish formed the bulk of otter diet, which included also frogs, mammals, and reptiles. By DNA barcoding (success rate: 72.38%), we identified 79 prey items from 105 bone remains. The diet comprised mostly fish, but frogs, mammals, and reptiles were also identified. The fish fauna and otter diet composition differed significantly. Across the study sites, members of the Cyprinidae dominated in netted samples, but occurred less frequently in otter diet. Because most Cyprinidae are fast swimmers, otters also fed on benthic fishes and frogs, suggesting limited foraging flexibility in otters and specialization on more slowly moving prey.
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Affiliation(s)
- Sungwon Hong
- Department of Biological Sciences, Pusan National University, Jangjeon-dong, Gumjeong-gu, Busan 46241, Republic of Korea
| | - Jeong-Soo Gim
- Department of Biological Sciences, Pusan National University, Jangjeon-dong, Gumjeong-gu, Busan 46241, Republic of Korea
| | - Hyo Gyeom Kim
- Department of Biological Sciences, Pusan National University, Jangjeon-dong, Gumjeong-gu, Busan 46241, Republic of Korea
| | - Phil E. Cowan
- Manaaki Whenua Landcare Research, Lincoln 7640, New Zealand
| | - Gea-Jae Joo
- Department of Biological Sciences, Pusan National University, Jangjeon-dong, Gumjeong-gu, Busan 46241, Republic of Korea
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Smiroldo G, Gariano P, Balestrieri A, Manenti R, Pini E, Tremolada P. Predation on Amphibians May Enhance Eurasian Otter Recovery in Southern Italy. Zoolog Sci 2019; 36:273-283. [PMID: 34664897 DOI: 10.2108/zs180147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/06/2019] [Indexed: 11/17/2022]
Abstract
Mediterranean freshwaters undergo extreme seasonal variation in water flow, which, exacerbated by water withdrawal for agriculture or hydroelectric purposes, may affect fish communities and thus prey availability for semi-aquatic predators, such as Eurasian otter Lutra lutra. To investigate the role played by food availability on the ongoing recovery of an otter population at the southernmost limit of its Italian range, we assessed otter diet by the analysis of 357 spraints collected from 2014 to 2017 on eight rivers, and both fish and amphibian availability by, respectively, electrofishing and visual encounter surveys. Fish and amphibians formed the bulk of otter diet, the latter resource contributing as much as fish to otter diet in spring. Use by otters of both fish and amphibians depended only fish availability, suggesting that amphibians constituted an alternative resource to be exploited in conditions of fish shortage. Accordingly, electrofishing showed that fish biomass may barely be sufficient to sustain the current otter population. ATR-FT-IR spectroscopy allowed to point out for the first time the occurrence of amphibian eggs in otter spraints, although the co-occurrence of anuran bones did not allow to discriminate between direct and passive predation. Overall results indicate that the expansion or even survival of this small otter population may depend on the effective management of water resources and reinforcement of fish assemblages.
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Affiliation(s)
- Giorgio Smiroldo
- Department of Environmental Sciences and Policy, University of Milan, I-20133 Milan, Italy,
| | | | - Alessandro Balestrieri
- Department of Environmental Sciences and Policy, University of Milan, I-20133 Milan, Italy
| | - Raoul Manenti
- Department of Environmental Sciences and Policy, University of Milan, I-20133 Milan, Italy
| | - Elena Pini
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Generale e Organica "A. Marchesini", Università di Milano, I-20133 Milan, Italy
| | - Paolo Tremolada
- Department of Environmental Sciences and Policy, University of Milan, I-20133 Milan, Italy
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Smiroldo G, Villa A, Tremolada P, Gariano P, Balestrieri A, Delfino M. Amphibians in Eurasian otter
Lutra lutra
diet: osteological identification unveils hidden prey richness and male‐biased predation on anurans. Mamm Rev 2019. [DOI: 10.1111/mam.12155] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Giorgio Smiroldo
- Department of Environmental Sciences and PolicyUniversity of Milan Via G. Celoria, 26 I‐20133 Milan Italy
| | - Andrea Villa
- Dipartimento di Scienze della TerraUniversità di Torino Via Valperga Caluso 35 10125 Torino Italy
| | - Paolo Tremolada
- Department of Environmental Sciences and PolicyUniversity of Milan Via G. Celoria, 26 I‐20133 Milan Italy
| | | | - Alessandro Balestrieri
- Department of Environmental Sciences and PolicyUniversity of Milan Via G. Celoria, 26 I‐20133 Milan Italy
| | - Massimo Delfino
- Department of Environmental Sciences and PolicyUniversity of Milan Via G. Celoria, 26 I‐20133 Milan Italy
- Institut Català de Paleontologia Miquel CrusafontUniversitat Autònoma de Barcelona Edifici ICP, Campus de la UAB s/n 08193 Cerdanyola del Vallès Barcelona Spain
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Petrov K, Lewis J, Malkiewicz N, Van Dyke JU, Spencer RJ. Food abundance and diet variation in freshwater turtles from the mid-Murray River, Australia. AUST J ZOOL 2018. [DOI: 10.1071/zo17060] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Consumers usually respond to variations in prey availability by altering their foraging strategies. Generalist consumers forage on a diversity of resources and have greater potential to ‘switch’ their diet in response to fluctuations in prey availability, in comparison to specialist consumers. We aimed to determine how the diets of two specialist species (the eastern long-necked turtle (Chelodina longicollis) and the broad-shelled turtle (Chelodina expansa) and the more generalist Murray River short-necked turtle (Emydura macquarii) respond to variation in habitat and prey availability. We trapped and stomach-flushed turtles, and compared their diets along with environmental variables (turbidity, macrophyte and filamentous green algae cover, and aquatic invertebrate diversity and abundance) at four wetlands in north-central Victoria. Diets of E. macquarii differed from those of both Chelodina species, which overlapped, across all four sites. However, samples sizes for the two Chelodina species were too small to compare among-wetland variation in diet. Dietary composition of E. macquarii was variable but did not differ statistically among sites. Emydura macquarii preferentially selected filamentous green algae at three of the four sites. Where filamentous green algae were rare, total food bolus volume was reduced and E. macquarii only partially replaced it with other food items, including other vegetation, wood, and animal prey. Many turtles at these sites also had empty stomachs. Thus, filamentous green algae may be a limiting food for E. macquarii. Although E. macquarii has previously been described as a generalist, it appears to have limited ability to replace filamentous green algae with other food items when filamentous green algae are rare.
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Martínez-Abraín A, Jiménez J. Anthropogenic areas as incidental substitutes for original habitat. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2016; 30:593-598. [PMID: 26483140 DOI: 10.1111/cobi.12644] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/23/2015] [Accepted: 09/29/2015] [Indexed: 06/05/2023]
Abstract
One speaks of ecological substitutes when an introduced species performs, to some extent, the ecosystem function of an extirpated native species. We suggest that a similar case exists for habitats. Species evolve within ecosystems, but habitats can be destroyed or modified by natural and human-made causes. Sometimes habitat alteration forces animals to move to or remain in a suboptimal habitat type. In that case, the habitat is considered a refuge, and the species is called a refugee. Typically refugee species have lower population growth rates than in their original habitats. Human action may lead to the unintended generation of artificial or semiartificial habitat types that functionally resemble the essential features of the original habitat and thus allow a population growth rate of the same magnitude or higher than in the original habitat. We call such areas substitution habitats and define them as human-made habitats within the focal species range that by chance are partial substitutes for the species' original habitat. We call species occupying a substitution habitat adopted species. These are 2 new terms in conservation biology. Examples of substitution habitats are dams for European otters, wheat and rice fields for many steppeland and aquatic birds, and urban areas for storks, falcons, and swifts. Although substitution habitats can bring about increased resilience against the agents of global change, the conservation of original habitat types remains a conservation priority.
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Affiliation(s)
- Alejandro Martínez-Abraín
- Evolutionary Biology Group, Facultad de Ciencias, Universidade da Coruña, Campus da Zapateira s/n, 15071, A Coruña, Spain.
- Population Ecology Group, Mediterranean Institute of Advanced Studies (CSIC-UIB), C/Miquel Marquès 21, 07190, Esporles, Mallorca, Spain.
| | - Juan Jiménez
- Servicio de Vida Silvestre, Consellería de Infraestructuras, Territorio y Medio Ambiente, Generalitat Valenciana, C/ Castán Tobeñas, 77, 46018, Valencia, Spain
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Kloskowski J, Rechulicz J, Jarzynowa B. Resource availability and use by Eurasian ottersLutra lutrain a heavily modified river-canal system. WILDLIFE BIOLOGY 2013. [DOI: 10.2981/12-104] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Brzeziński M, Chibowska P, Romanowski J. Dam reservoir affects diet of otters inhabiting mountain river in SE Poland. FOLIA ZOOLOGICA 2013. [DOI: 10.25225/fozo.v62.i1.a8.2013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Marcin Brzeziński
- Department of Ecology, University of Warsaw, ul. Banacha 2, 02-097 Warsaw, Poland
| | - Patrycja Chibowska
- Department of Ecology, University of Warsaw, ul. Banacha 2, 02-097 Warsaw, Poland
| | - Jerzy Romanowski
- Centre for Ecological Research, Polish Academy of Sciences, ul. Konopnickiej 1, 05-092 Łomianki, Poland
- Faculty of Biology and Environmental Studies UKSW, Wóycickiego 1/3, 01-938 Warsaw, Poland
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Novais A, Sedlmayr A, Moreira-Santos M, Gonçalves F, Ribeiro R. Diet of the otter Lutra lutra in an almost pristine Portuguese river: seasonality and analysis of fish prey through scale and vertebrae keys and length relationships. MAMMALIA 2010. [DOI: 10.1515/mamm.2010.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The seasonal diet and size of fish prey of the otter Lutra lutra were studied in an almost pristine river of North Portugal (Paiva river) through the analysis of spraints collected during 1 year. To identify Iberian freshwater fish species (Salmo trutta, Micropterus salmoides, Lepomis gibbosus, Luciobarbus bocagei, Cyprinus carpio, Carassius auratus, Pseudochondrostoma polylepis, Achondrostoma arcasii, and Iberocypris alburnoides) consumed by the otter keys based on scales and vertebrae were first developed and tested. Both keys allowed identification of all fish species, although three Cyprinidae species could not be discriminated (P. polylepis, A. arcasii, and I. alburnoides). Regression equations were calculated to estimate the dimensions of preyed fish. Highly significant linear relationships were obtained for the standard length versus vertebrae measurements, for all fish species, except for C. carpio. Fish was the predominant prey category in autumn and winter, but the otter also preyed on amphibians, reptiles, mammals, and birds, particularly during spring and summer. In general, the otter consumed high proportions of small size fish (3–12 cm for the three indiscriminate Cyprinidae, 3–9 cm for C. carpio, and 6–12 cm for S. trutta).
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Affiliation(s)
| | - Ambra Sedlmayr
- IMAR – CMA, Department of Zoology, University of Coimbra, Largo Marquês de Pombal, P-3004-517, Coimbra, Portugal
| | - Matilde Moreira-Santos
- IMAR – CMA, Department of Zoology, University of Coimbra, Largo Marquês de Pombal, P-3004-517, Coimbra, Portugal
| | - Fernando Gonçalves
- CESAM and Departamento de Biologia da Universidade de Aveiro, Campus Universitário de Santiago, P-3810-193 Aveiro, Portugal
| | - Rui Ribeiro
- IMAR – CMA, Department of Zoology, University of Coimbra, Largo Marquês de Pombal, P-3004-517, Coimbra, Portugal
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