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Ambio

Title:		Resilience of an aquatic macrophyte to an anthropogenically induced environmental stressor in a Ramsar wetland of southern Chile
Author(s):		Jaramillo E; Duarte C; Labra FA; Lagos NA; Peruzzo B; Silva R; Velasquez C; Manzano M; Melnick D;
Address:		"Instituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. edojaramillo@gmail.com. Departamento de Ecologia y Biodiversidad, Facultad de Ecologia y Recursos Naturales, Universidad Andres Bello, Santiago, Chile. Centro de Investigacion e Innovacion, para el Cambio Climatico, Facultad de Ciencias, Universidad Santo Tomas, Santiago, Chile. Instituto de Anatomia, Histologia y Patologia, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile. Instituto de Ciencias de la Tierra, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile"
Journal Title:		Ambio
Year:		2019
Volume:		20180703
Issue:		3
Page Number:		304 - 312
DOI:		10.1007/s13280-018-1071-6
ISSN/ISBN:		1654-7209 (Electronic) 0044-7447 (Print) 0044-7447 (Linking)
Abstract:		"In mid-2004, anthropogenically induced changes in water quality of the Rio Cruces wetland, a Ramsar site located in southern Chile (ca. 40 degrees 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 Rio 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"
Keywords:		Chile Herbivory Humans *Hydrocharitaceae Water Quality *Wetlands Environmental changes Iron loads in plants Spatial occurrence of aquatic macrophytes Wetland;
Notes:		"MedlineJaramillo, Eduardo Duarte, Cristian Labra, Fabio A Lagos, Nelson A Peruzzo, Bruno Silva, Ricardo Velasquez, Carlos Manzano, Mario Melnick, Daniel eng 1210-1203/2004/CONAMA/ Sweden 2018/07/05 Ambio. 2019 Mar; 48(3):304-312. doi: 10.1007/s13280-018-1071-6. Epub 2018 Jul 3"