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Management of saltpans as potential foraging sites for shorebirds

Rodríguez Montero, Luna (2012) BIOM24 20121
Degree Projects in Biology
Abstract
Abstract

Estuaries and salt marshes are important wetlands used by waterbirds during winter and migration. However, many salt-marshes have been transformed into salinas, which currently function as high-tide roosts. Since traditional salt production is no longer profitable, many salinas have been abandoned or converted into aquaculture potentially becoming less attractive to waders. In this study we investigate the use of salinas by foraging waders that differ in management type. Unmanaged salinas (i.e. abandoned) held less benthic biomass than Managed Salinas and also had lower densities of waders. Waders of distinct sizes showed affinities for different water regimes (from dry to flooded) and these also affected prey distribution and... (More)
Abstract

Estuaries and salt marshes are important wetlands used by waterbirds during winter and migration. However, many salt-marshes have been transformed into salinas, which currently function as high-tide roosts. Since traditional salt production is no longer profitable, many salinas have been abandoned or converted into aquaculture potentially becoming less attractive to waders. In this study we investigate the use of salinas by foraging waders that differ in management type. Unmanaged salinas (i.e. abandoned) held less benthic biomass than Managed Salinas and also had lower densities of waders. Waders of distinct sizes showed affinities for different water regimes (from dry to flooded) and these also affected prey distribution and abundance. Some management actions, (e.g. flooding and emptying ponds) promoted prey abundance offering the most profitable foraging sites. Moist and exposed sediments held the highest biomass for all waders. We therefore suggest that salinas with a dynamic management provide the best foraging conditions.

Popular science summary:

Managing salinas for shorebirds


Estuaries and salt marshes are important wetlands used by waterbirds during winter and migration. Many salt-marshes have been transformed into salinas, which currently function as high-tide sites for roosting and feeding birds. Since traditional salt production is no longer profitable, many salinas have been abandoned or converted into aquaculture, potentially becoming less attractive to shorebirds. This could contribute to the already ongoing general decline in shorebirds population.

Salinas are composed of ponds of different sizes connected to each other. Even if they are man-made, they are recognized as a functional part of wetlands with high biological richness. In this study we wanted to answer the question: which factors best explain the quality of salinas as a foraging habitat for shorebirds?

On the one hand we investigated the use of salinas by feeding shorebirds that differ in morphological features (that is, leg and bill length). On the other hand we looked into macroinvertebrates communities living in the sediment of the salinas ponds, since they are the main food for shorebirds. We chose six different ponds of salinas that differ in management type. Three of them belonged to a managed salina and the other ponds belonged to an abandoned and unmanaged salina. The last objective of the project was to establish how different management actions are affecting both birds and macroinvertebrates distribution and abundance.


Results
Unmanaged salinas held less macroinvertebrates biomass than managed Salinas and also had lower densities of shorebirds. Waterbirds of distinct sizes showed affinities for different water regimes (from dry to flooded) and these also affected prey distribution and abundance. Moist and exposed sediments held the highest biomass for all waders. Dynamic management actions, e.g. flooding and emptying ponds, resulted in prey abundances offering the most profitable foraging sites.

We suggest that salinas with a dynamic management provide the best foraging conditions for shorebirds, creating a mixture of habitats increasing biodiversity of both shorebirds and macroinvertebrate communities.


Advisor: Åke Lindström
Master´s Degree Project 30 credits in 2012
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Rodríguez Montero, Luna
supervisor
organization
course
BIOM24 20121
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
3633624
date added to LUP
2013-04-16 16:01:35
date last changed
2013-04-16 16:01:35
@misc{3633624,
  abstract     = {Abstract

Estuaries and salt marshes are important wetlands used by waterbirds during winter and migration. However, many salt-marshes have been transformed into salinas, which currently function as high-tide roosts. Since traditional salt production is no longer profitable, many salinas have been abandoned or converted into aquaculture potentially becoming less attractive to waders. In this study we investigate the use of salinas by foraging waders that differ in management type. Unmanaged salinas (i.e. abandoned) held less benthic biomass than Managed Salinas and also had lower densities of waders. Waders of distinct sizes showed affinities for different water regimes (from dry to flooded) and these also affected prey distribution and abundance. Some management actions, (e.g. flooding and emptying ponds) promoted prey abundance offering the most profitable foraging sites. Moist and exposed sediments held the highest biomass for all waders. We therefore suggest that salinas with a dynamic management provide the best foraging conditions.

Popular science summary:

Managing salinas for shorebirds


Estuaries and salt marshes are important wetlands used by waterbirds during winter and migration. Many salt-marshes have been transformed into salinas, which currently function as high-tide sites for roosting and feeding birds. Since traditional salt production is no longer profitable, many salinas have been abandoned or converted into aquaculture, potentially becoming less attractive to shorebirds. This could contribute to the already ongoing general decline in shorebirds population.

Salinas are composed of ponds of different sizes connected to each other. Even if they are man-made, they are recognized as a functional part of wetlands with high biological richness. In this study we wanted to answer the question: which factors best explain the quality of salinas as a foraging habitat for shorebirds? 

On the one hand we investigated the use of salinas by feeding shorebirds that differ in morphological features (that is, leg and bill length). On the other hand we looked into macroinvertebrates communities living in the sediment of the salinas ponds, since they are the main food for shorebirds. We chose six different ponds of salinas that differ in management type. Three of them belonged to a managed salina and the other ponds belonged to an abandoned and unmanaged salina. The last objective of the project was to establish how different management actions are affecting both birds and macroinvertebrates distribution and abundance.


Results
Unmanaged salinas held less macroinvertebrates biomass than managed Salinas and also had lower densities of shorebirds. Waterbirds of distinct sizes showed affinities for different water regimes (from dry to flooded) and these also affected prey distribution and abundance. Moist and exposed sediments held the highest biomass for all waders. Dynamic management actions, e.g. flooding and emptying ponds, resulted in prey abundances offering the most profitable foraging sites. 

We suggest that salinas with a dynamic management provide the best foraging conditions for shorebirds, creating a mixture of habitats increasing biodiversity of both shorebirds and macroinvertebrate communities.


Advisor: Åke Lindström
Master´s Degree Project 30 credits in 2012
Department of Biology, Lund University},
  author       = {Rodríguez Montero, Luna},
  language     = {eng},
  note         = {Student Paper},
  title        = {Management of saltpans as potential foraging sites for shorebirds},
  year         = {2012},
}