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Norris D, Michalski F. Carnivore coexistence without competition: giant otters are more nocturnal around dens than sympatric neotropical otters. PeerJ 2024; 12:e17244. [PMID: 38590704 PMCID: PMC11000638 DOI: 10.7717/peerj.17244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 03/25/2024] [Indexed: 04/10/2024] Open
Abstract
Nocturnal activity of tropical otters is rarely reported. To date no studies have documented den use by sympatric giant (Pteronura brasiliensis) and neotropical otters (Lontra longicaudis). We used camera-traps to monitor den use by sympatric otters along an equatorial Amazonian river. Camera-traps provided evidence that giant otters were more nocturnal around dens than sympatric neotropical otters. Nocturnal activity was recorded in 11% of giant otter photos (n = 14 of 125 photos), but was recorded only once for neotropical otters. Den use by giant and neotropical otters overlapped spatially and temporally but not concurrently. We hypothesize that previously reported nocturnal activity in neotropical otters is facilitated by the absence or low density of giant otters. Our results also underscore the need to use complementary techniques together with den counts for monitoring otters as sympatric species can use the same dens.
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Affiliation(s)
- Darren Norris
- Environmental Sciences, Federal University of Amapá, Macpá, Brazil
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil
| | - Fernanda Michalski
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil
- Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapa, Brazil
- Pro-Carnivores Institute, Atibaia, São Paulo, Brazil
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Norris D, Michalski F. Human disturbances and the daytime activity of sympatric otters along equatorial Amazonian rivers. PeerJ 2023; 11:e15742. [PMID: 37492398 PMCID: PMC10364808 DOI: 10.7717/peerj.15742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 06/21/2023] [Indexed: 07/27/2023] Open
Abstract
Background Previous studies suggest coexistence between sympatric neotropical (Lontra longicaudis) and giant otters (Pteronura brasiliensis) maybe facilitated by temporal and spatial differences in activity. Yet, to date there has been no systematic evaluation of activity of these species in sympatry. Here we use extensive multi-year field data to compare temporal and spatial patterns in the diurnal activity of sympatric giant and neotropical otters to answer three questions: Do temporal patterns in daytime river use change in relation to seasonal river levels (low, rising, high and declining river levels), do they change due to human disturbances (boats and fishing nets) and do patterns in neotropical otter activity change due to the presence of the larger sized giant otter? Methods Direct observations of both species were recorded using standardized boat surveys along 218 km of rivers over 53 months during nine years (2011-2013 and 2015-2020). Complementary techniques (Generalized Additive Models, Kernel density estimates and non-parametric tests,) were used to compare diurnal activity patterns along rivers subdivided into 41 river reaches. Results The presence of giant otters decreased threefold from 67% of the least disturbed reaches (few boats no fishing nets) to 18% of the most disturbed reaches with many boats and fishing nets. In contrast neotropical otter presence nearly doubled from 44% of the least disturbed to 73% of the most disturbed reaches with fewest giant otter detections. Both species were observed across all daytime hours but were observed rarely on the same day. There was no evidence to suggest simultaneous use of the same reach. When species were detected on the same day, they were separated spatially (median distance between species 12.5 km) and temporally (median time difference 3.0 hours). There was little change in activity of either species among seasons. Giant otters were less active in river reaches with fishing nets and boat use, whereas neotropical otter activity did not appear to be strongly affected by these activities. Conclusions Our findings support evidence that diurnal activity in both otter species is flexible, with daytime activity changing due to human disturbances in the case of giant otters.
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Affiliation(s)
- Darren Norris
- Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil
- Environmental Sciences, Federal University of Amapá, Macapá, Amapá, Brazil
| | - Fernanda Michalski
- Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil
- Pro-Carnivores Institute, Atibaia, São Paulo, Brazil
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Raffo DCD, Norris D, Hartz SM, Michalski F. Anthropogenic influences on the distribution of a threatened apex-predator around sustainable-use reserves following hydropower dam installation. PeerJ 2022; 10:e14287. [PMID: 36285331 PMCID: PMC9588301 DOI: 10.7717/peerj.14287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/02/2022] [Indexed: 01/24/2023] Open
Abstract
Although previous studies demonstrate declines in many large bodied species following hydropower dam installation, others suggest that some species, including the giant otter (Pteronura brasiliensis) may return to newly created reservoir habitats. Yet, there is a lack of evidence to support such theories. Here, we analyzed the effects of a hydropower dam on giant otters using a before-after control-impact study design in the eastern Brazilian Amazon. We collected data 3 years before (2011-2012 and 2015) and after (2017-2019) dam construction, totaling 6,459 km of surveys along rivers with 43 direct sightings of giant otters. Contrary to expectations, our results revealed that giant otters did not remain nor did they return to the dam reservoir. Beyond the zone directly impacted by the dam giant otter occurrence and relative abundance declined next to sustainable-use reserves where the river was more intensely used by people. Our study showed that in the absence of active management sustainable-use reserves and low human density were not sufficient to maintain this apex-predator. Our findings suggest a need to proactively create and maintain areas with low levels of anthropogenic disturbance to enable sustainable coexistence between energy demands and biodiversity across Amazonia.
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Affiliation(s)
- Deborah C. Dávila Raffo
- Postgraduate Programme in Ecology, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil,Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil
| | - Darren Norris
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil,School of Environmental Sciences, Federal University of Amapá, Macapá, Amapá, Brazil,Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil
| | - Sandra Maria Hartz
- Postgraduate Programme in Ecology, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Fernanda Michalski
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil,Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil,Pro-Carnivores Institute, Atibaia, São Paulo, Brazil
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Martins CB, Norris D, Michalski F. Diversity and activity of bird fauna in ephemeral river-created habitats in Amazonia. STUDIES ON NEOTROPICAL FAUNA AND ENVIRONMENT 2021. [DOI: 10.1080/01650521.2021.2005410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Cassiano Bueno Martins
- Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Brazil
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Brazil
| | - Darren Norris
- Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Brazil
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Brazil
- School of Environmental Sciences, Federal University of Amapá, Macapá, Brazil
| | - Fernanda Michalski
- Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Brazil
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Brazil
- Pro-Carnivores Institute, Atibaia, Brazil
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Norris D, Michalski F, Gibbs JP. Community based actions save Yellow-spotted river turtle ( Podocnemis unifilis) eggs and hatchlings flooded by rapid river level rises. PeerJ 2020; 8:e9921. [PMID: 32995087 PMCID: PMC7501802 DOI: 10.7717/peerj.9921] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/21/2020] [Indexed: 11/27/2022] Open
Abstract
The conservation and recovery of increasingly threatened tropical freshwater turtle populations depends on effective management plans and actions. Here we show that community-based actions saved Yellow-spotted river turtle (Podocnemis unifilis) eggs submerged by unseasonal flooding and ensured the release of hatchlings. We recovered 926 eggs and 65 premature hatchlings from 74 submerged nests at 16 flooded nesting areas along 75 km of waterways. The rescued eggs were transferred to a rearing center and incubated. Hatchlings emerged from eggs that had remained underwater for up to two days. Hatchlings were maintained in 250–500 L nursery tanks until yolk sac scars had closed. Healthy hatchlings were then immediately released around the original nesting areas. We released 599 hatchlings (60.4%) from 991 submerged eggs and hatchlings. Egg survival (61.7% (571/926)) was substantially less than hatchling survival (94.2% (599/636)) but within the expected range of values reported for this species. These findings suggest that Yellow-spotted river turtle eggs and embryos are resistant to short-term submersion, which could help explain the widespread distribution of this species across highly seasonal Amazonian rivers. Management plans should take the possible survival of submerged eggs into consideration as part of species conservation and recovery actions.
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Affiliation(s)
- Darren Norris
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil.,Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil.,School of Environmental Sciences, Federal University of Amapá, Macapá, Amapá, Brazil
| | - Fernanda Michalski
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil.,Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil.,Pro-Carnivores Institute, Atibaia, São Paulo, Brazil
| | - James P Gibbs
- Department of Environmental and Forest Biology, State University of New York, Syracuse, NY, USA
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Michalski F, Norris D, Quintana I, Valerio A, Gibbs JP. Substrate influences human removal of freshwater turtle nests in the eastern Brazilian Amazon. Sci Rep 2020; 10:8082. [PMID: 32415212 PMCID: PMC7228982 DOI: 10.1038/s41598-020-65074-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 04/27/2020] [Indexed: 11/09/2022] Open
Abstract
Substrate type determines nesting success and fitness in turtles and is a critical consideration for nesting area protection and restoration. Here, we evaluated the effect of substrate on nest removal by humans in the eastern Brazilian Amazon. We analyzed substrate composition and fate of 216 P. unifilis nests along 88 km of rivers. River segment and substrate type were the most important predictors of nest removal by humans. We found up to 36% lower removal of nests in fine sand and experimental results support the hypothesis that wind more often obscures tracks of nesting females in substrates with more (>66%) fine sand. Our findings are useful for informing the restoration of artificial nesting areas across the Amazon, as nesting area substrates should be selected not only to maintain hatchling sex ratios, but also to minimize nest removal by humans.
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Affiliation(s)
- Fernanda Michalski
- Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil. .,Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil. .,Pro-Carnivores Institute, Atibaia, São Paulo, Brazil.
| | - Darren Norris
- Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil.,Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil.,School of Environmental Sciences, Federal University of Amapá, Macapá, Amapá, Brazil
| | - Itxaso Quintana
- Ecology Department, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Andressa Valerio
- Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil.,Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil
| | - James P Gibbs
- Department of Forest and Environmental Biology, State University of New York, College of Environmental Science and Forestry, Syracuse, NY, USA
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Quintana I, Norris D, Valerio A, Becker FG, Gibbs JP, Michalski F. Nest removal by humans creates an evolutionary trap for Amazonian freshwater turtles. J Zool (1987) 2019. [DOI: 10.1111/jzo.12689] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- I. Quintana
- Ecology Department Universidade Federal do Rio Grande do Sul (UFRGS) Porto Alegre Brazil
| | - D. Norris
- School of Environmental Sciences Federal University of Amapá Macapá Brazil
- Postgraduate Programme in Tropical BiodiversityFederal University of Amapá Macapá Brazil
- Ecology and Conservation of Amazonian Vertebrates Research Group Federal University of Amapá Macapá Brazil
| | - A. Valerio
- Postgraduate Programme in Tropical BiodiversityFederal University of Amapá Macapá Brazil
- Ecology and Conservation of Amazonian Vertebrates Research Group Federal University of Amapá Macapá Brazil
| | - F. G. Becker
- Ecology Department Universidade Federal do Rio Grande do Sul (UFRGS) Porto Alegre Brazil
| | - J. P. Gibbs
- Department of Forest and Environmental Biology State University of New York College of Environmental Science and Forestry Syracuse NY USA
| | - F. Michalski
- Postgraduate Programme in Tropical BiodiversityFederal University of Amapá Macapá Brazil
- Ecology and Conservation of Amazonian Vertebrates Research Group Federal University of Amapá Macapá Brazil
- Instituto Pró‐Carnívoros Atibaia, São Paulo Brazil
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Norris D, Michalski F, Gibbs JP. Community involvement works where enforcement fails: conservation success through community-based management of Amazon river turtle nests. PeerJ 2018; 6:e4856. [PMID: 29868271 PMCID: PMC5985759 DOI: 10.7717/peerj.4856] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/08/2018] [Indexed: 11/30/2022] Open
Abstract
Law enforcement is widely regarded as a cornerstone to effective natural resource management. Practical guidelines for the optimal use of enforcement measures are lacking particularly in areas protected under sustainable and/or mixed use management regimes and where legal institution are weak. Focusing on the yellow-spotted river turtles (Podocnemis unifilis) along 33 km of river that runs between two sustainable–use reserves in the Brazilian Amazon as an illustrative example, we show that two years of patrols to enforce lawful protection regulations had no effect on nest harvesting. In contrast, during one year when community-based management approaches were enacted harvest levels dropped nearly threefold to a rate (26%) that is likely sufficient for river turtle population recovery. Our findings support previous studies that show how community participation, if appropriately implemented, can facilitate effective natural resource management where law enforcement is limited or ineffective.
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Affiliation(s)
- Darren Norris
- School of Environmental Sciences, Federal University of Amapá, Macapá, Amapá, Brazil.,Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil.,Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil
| | - Fernanda Michalski
- Ecology and Conservation of Amazonian Vertebrates Research Group, Federal University of Amapá, Macapá, Amapá, Brazil.,Postgraduate Programme in Tropical Biodiversity, Federal University of Amapá, Macapá, Amapá, Brazil.,Instituto Pró-Carnívoros, Atibaia, São Paulo, Brazil
| | - James P Gibbs
- Department of Forest and Environmental Biology, State University of New York (SUNY), Syracuse, NY, United States of America
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