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Rodríguez-Jorquera IA, Lenzi J, Maturana M, Biscarra G, Ruiz J, Navedo JG. Exploring the recovery of a large wetland using black-necked swan blood parameters and body condition 16 years after a pollution-induced disturbance. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2023; 19:663-675. [PMID: 36793140 DOI: 10.1002/ieam.4748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 02/04/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Resilience theory has taken center stage in tackling the challenge of wetland recovery on a fast-changing planet. Because of waterbirds' enormous dependence on wetlands, their numbers have long been used as surrogates for wetland recovery over time. However, immigration of individuals can mask actual recoveries at a given wetland. One alternative to expanding the knowledge of wetland recovery is the use of physiological parameters from aquatic organism populations. We explored the variations in the physiological parameters of black-necked swan (BNS) before, during, and after a 16-year period of a pollution-induced disturbance that originated in a pulp-mill wastewater discharge. This disturbance triggered the precipitation of iron (Fe) in the water column of the Río Cruces Wetland in southern Chile, one of the main sites for the global population of BNS Cygnus melancoryphus. We compared our recent (2019) original data (body mass index [BMI], hematocrit, hemoglobin, mean corpuscular volume, blood enzymes, and metabolites) with available datasets from the site obtained before the pollution-induced disturbance (2003) and immediately after the disturbance (2004). Results indicate that, 16 years after the pollution-induced disturbance, some important parameters of animal physiology did not return to their pre-disturbance state. For instance, BMI, triglycerides, and glucose were significantly higher in 2019 than in 2004, right after the disturbance. By contrast, the hemoglobin concentration was significantly lower in 2019 than in 2003 and 2004, and uric acid was 42% higher in 2019 than in 2004. Our results demonstrate that, despite higher BNS numbers with larger body weights present in 2019, the Río Cruces wetland has only partially recovered. We suggest that the impact of megadrought and wetland disappearance far from the site results in high rate of swan immigration, casting uncertainty about using the number of swans alone as honest indicators of wetland recovery after a pollution disturbance. Integr Environ Assess Manag 2023;19:663-675. © 2023 SETAC.
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Affiliation(s)
| | - Javier Lenzi
- Department of Biology, University of North Dakota, Grand Forks, North Dakota, USA
| | | | - Gabriela Biscarra
- Bird Ecology Lab, Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Los Ríos, Chile
| | - Jorge Ruiz
- Bird Ecology Lab, Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Los Ríos, Chile
| | - Juan G Navedo
- Centro de Humedales Río Cruces, Universidad Austral de Chile, Valdivia, Los Ríos, Chile
- Bird Ecology Lab, Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Los Ríos, Chile
- Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile
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Velásquez C, Jaramillo E, Camus P, Labra F, San Martín C. Dietary habits of the black-necked swan Cygnus melancoryphus (Birds: Anatidae) and variability of the aquatic macrophyte cover in the Río Cruces wetland, southern Chile. PLoS One 2019; 14:e0226331. [PMID: 31856223 PMCID: PMC6922417 DOI: 10.1371/journal.pone.0226331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 11/24/2019] [Indexed: 11/19/2022] Open
Abstract
The black-necked swan Cygnus melancoryphus is an aquatic herbivorous bird whose dietary habits depend on the dominance and accessibility of macrophyte banks in shallow areas of coastal and limnetic wetlands in southern South America. The swans from the Río Cruces wetland in southern Chile (ca. 39°S) feed mainly on the macrophyte Egeria densa from the water column between depths from less than 0,5 and 2,0 m. A micro- histological analysis of black-necked swan feces (N = 152) collected during six sampling occasions between 2012 and 2017 confirms the preferred consumption of E. densa and highlights the impact of temporal changes in the cover of these macrophytes on the swan's diet. The dietary composition of black-necked swans appears as a reliable proxy for temporal changes in the distribution of the most common aquatic macrophytes in the Río Cruces wetland. These results highlight the importance of preserving shallow wetlands as the habitat for aquatic macrophytes that provide the main food source for these herbivorous water birds.
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Affiliation(s)
| | - Eduardo Jaramillo
- Instituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Patricio Camus
- Departamento de Ecología, Facultad de Ciencias, Universidad Católica de la Santísima Concepción, Concepción, Chile
- Centro de Investigación en Biodiversidad y Ambientes Sustentables (CIBAS), Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Fabio Labra
- Centro de Investigación e Innovación para el Cambio Climático, Facultad de Ciencias, Universidad Santo Tomás, Santiago, Chile
| | - Cristina San Martín
- Instituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
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Jaramillo E, Duarte C, Labra FA, Lagos NA, Peruzzo B, Silva R, Velasquez C, Manzano M, Melnick D. Resilience of an aquatic macrophyte to an anthropogenically induced environmental stressor in a Ramsar wetland of southern Chile. AMBIO 2019; 48:304-312. [PMID: 29971664 PMCID: PMC6374225 DOI: 10.1007/s13280-018-1071-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/11/2018] [Accepted: 06/16/2018] [Indexed: 05/10/2023]
Abstract
In mid-2004, anthropogenically induced changes in water quality of the Río Cruces wetland, a Ramsar site located in southern Chile (ca. 40°S), enhanced the resuspension of iron-enriched sediments, which were subsequently deposited over the most abundant aquatic macrophyte of the wetland (Egeria densa Planch. 1849). This event triggered the formation of brownish, necrotic patches and increased iron contents in the leaves and stems of E. densa, which contributed to a significant demise of the plant within the wetland. In this study, we estimate the recovery time as a proxy for resilience of this macrophyte at organismal and population levels. Macro- and micro-optical characteristics, as well as iron contents in tissues of E. densa, were documented in four time windows (2004, 2008, 2012, and 2014). In addition, the size of the macrophyte population and its spatial occurrence were monitored from 2008 to 2016 across 36 study sites within the wetland. Our results suggest necrotic patches and high iron contents in E. densa persisted at least until 2008. After 2013, a significant increase in the spatial occurrence of E. densa was observed within the wetland, reaching full recovery of the population during 2015. The health of plant tissues and iron contents in leaves and stems showed recovery period close to 4 years, while the recovery of the spatial occurrence of E. densa took approximately 9 years. While the monitoring of plant health was not performed on a strict annual basis, the recovery rates estimated here are slower than those described for other macrophytes. This finding might reflect the long-lasting effects of the disturbance from 2004 and the interaction with biotic processes, such as foraging by waterbirds recolonizing the Río Cruces wetland. These results show that full recovery of E. densa was achieved through a cascade of effects starting with abiotic factors (water quality) and passing through physiological and individual levels, to finally reach the population level. A key aspect of this response is the invasive nature of the macrophyte, which likely contributed to its recovery as a consequence of improved water quality. Less successful macrophyte species in other systems may not reach the specific population recovery, and become subdominant species instead, or even be eradicated from the wetland either as the result of herbivory or due to competition with other macrophytes.
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Affiliation(s)
- Eduardo Jaramillo
- Instituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Cristian Duarte
- Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Santiago, Chile
| | - Fabio A. Labra
- Centro de Investigación e Innovación, para el Cambio Climático, Facultad de Ciencias, Universidad Santo Tomás, Santiago, Chile
| | - Nelson A. Lagos
- Centro de Investigación e Innovación, para el Cambio Climático, Facultad de Ciencias, Universidad Santo Tomás, Santiago, Chile
| | - Bruno Peruzzo
- Instituto de Anatomía, Histología y Patología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - Ricardo Silva
- Instituto de Anatomía, Histología y Patología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - Carlos Velasquez
- Instituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Mario Manzano
- Instituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Daniel Melnick
- Instituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
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Wood KA, Newth JL, Hilton GM, Rees EC. Has winter body condition varied with population size in a long-distance migrant, the Bewick’s Swan (Cygnus columbianus bewickii)? EUR J WILDLIFE RES 2018. [DOI: 10.1007/s10344-018-1200-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Minias P. The use of haemoglobin concentrations to assess physiological condition in birds: a review. CONSERVATION PHYSIOLOGY 2015; 3:cov007. [PMID: 27293692 PMCID: PMC4778452 DOI: 10.1093/conphys/cov007] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Revised: 02/02/2015] [Accepted: 02/04/2015] [Indexed: 05/05/2023]
Abstract
Total blood haemoglobin concentration is increasingly being used to assess physiological condition in wild birds, although it has not been explicitly recognized how reliably this parameter reflects different components of individual quality. Thus, I reviewed over 120 published studies linking variation in haemoglobin concentrations to different measures of condition and other phenotypic or ecological traits. In most of the studied avian species, haemoglobin concentrations were positively correlated with other commonly used indices of condition, such as body mass and fat loads, as well as with quality of the diet. Also, chick haemoglobin concentrations reliably reflected the intensity of nest infestation by parasitic arthropods, and haemoglobin was suggested to reflect parasitism by haematophagous ectoparasites much more precisely than haematocrit. There was also some evidence for the negative effect of helminths on haemoglobin levels in adult birds. Finally, haemoglobin concentrations were found to correlate with such fitness-related traits as timing of arrival at breeding grounds, timing of breeding, egg size, developmental stability and habitat quality, although these relationships were not always consistent between species. In consequence, I recommend the total blood haemoglobin concentration as a relatively robust indicator of physiological condition in birds, although this parameter is also strongly affected by age, season and the process of moult. Thus, researchers are advised to control fully for these confounding effects while using haemoglobin concentrations as a proxy of physiological condition in both experimental and field studies on birds.
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Affiliation(s)
- Piotr Minias
- Department of Teacher Training and Biodiversity Studies, University of Łódź, Banacha 1/3, Łódź 90–237, Poland
- Corresponding author:
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