TY - JOUR
T1 - Resilience of an aquatic macrophyte to an anthropogenically induced environmental stressor in a Ramsar wetland of southern Chile
AU - Jaramillo, Eduardo
AU - Duarte, Cristian
AU - Labra, Fabio A.
AU - Lagos, Nelson A.
AU - Peruzzo, Bruno
AU - Silva, Ricardo
AU - Velasquez, Carlos
AU - Manzano, Mario
AU - Melnick, Daniel
N1 - Funding Information:
Acknowledgements This study was primarily supported by the former Comisión Nacional del Medio Ambiente (CONAMA, Chile) (Contract N° 1210-1203/2004); Servicio de Evaluación Ambiental (SEA, Chile); and Ministerio del Medio Ambiente (MMA, Chile). Partial financial support was provided by the Company ARAUCO during 2015 and 2016, under the contract agreement signed by this company and the Universidad Austral de Chile, to carry out an interannual monitoring program on the abiotic and biotic features of the wetland.
Funding Information:
This study was primarily supported by the former Comisi?n Nacional del Medio Ambiente (CONAMA, Chile) (Contract N? 1210-1203/2004); Servicio de Evaluaci?n Ambiental (SEA, Chile); and Ministerio del Medio Ambiente (MMA, Chile). Partial financial support was provided by the Company ARAUCO during 2015 and 2016, under the contract agreement signed by this company and the Universidad Austral de Chile, to carry out an interannual monitoring program on the abiotic and biotic features of the wetland.
Publisher Copyright:
© 2018, Royal Swedish Academy of Sciences.
PY - 2018/7/3
Y1 - 2018/7/3
N2 - 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.
AB - 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.
KW - Environmental changes
KW - Iron loads in plants
KW - Spatial occurrence of aquatic macrophytes
KW - Wetland
UR - http://www.scopus.com/inward/record.url?scp=85042062336&partnerID=8YFLogxK
U2 - 10.1007/s13280-018-1071-6
DO - 10.1007/s13280-018-1071-6
M3 - Article
AN - SCOPUS:85042062336
SN - 0044-7447
VL - 48
SP - 1
EP - 9
JO - Ambio
JF - Ambio
IS - 3
ER -