CHANGING COMMUNITIES OF AQUATIC BIRDS IN WETLANDS OF THE MANCHA HÚMEDA BIOSPHERE RESERVE: METAPOPULATION ANALYSIS APPROACH G. Sánchez-Emeterio1, R. Gosálvez Rey2, J.A. Gil-Delgado3, D. Sanchez-Ramos4, M. Florín Beltrán4 1Facultad
de Educación de Toledo, Universidad de Castilla-La Mancha, Spain 2Departamento de Geografía y Ordenación del Territorio, Universidad de Castilla-La Mancha, Spain 3Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València, Spain 4Centro Regional de Estudios del Agua, Universidad de Castilla-La Mancha, Spain
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Figure 3. Evolution of the waterfowl species population (left) and relationship between population and size of the wetlands (right)
INTRODUCTION
RESULTS
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Wetland management at the network level remains a pending task.
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More than 70 waterfowl species were found, mostly concentrated in a few wetlands with seasonal behavior.
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Assessing changes in specific bird populations and how they use the wetlands is considered crucial for management.
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Three groups have been selected on the basis of their temporal strategies:
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The Mancha Húmeda Biosphere Reserve (MHBR) has large nesting and wintering waterfowl populations with conservation priority at European level.
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The wetlands in the MHBR are numerous and highly variable (intra- and inter-annually) habitats, so the waterfowl populations are also highly variable.
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MHBR has more than 100 wetlands in a protected area of about 418,000 ha. It is considered the greater protected area of mainland wetlands in Europe.
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The climate is semiarid and the hydrological functioning in the wetlands is asynchronous depending mainly of rains and aquifers.
2)
Breeding populations, specially in winter.
3)
Sedentary species.
Guild 1 (Divers) Guild 2 (Swimmers) Guild 3 (Crane fly) Tachybaptus ruficollis Anas clypeata Ciconia ciconia Anas crecca Anas penelope Larus fuscus Larus cachinnans Anas acuta Podiceps cristatus Anas querquedula Egretta garcetta Podiceps nigricollis Larus melanocephalus Bubulcus ibis Aythya ferina Larus ridibundus Oxyura leucocephala Anas strepera Fulica atra Tadorna tadorna Ardea cinerea Netta rufina Anas platyrhynchos Phoenicopterus roseus Guild 6 (l. visuals) Guild 7 (Marshland) Guild 8 (For feed) Calidris alpina Anser Anser Calidris minuta Grus grus Actitis hypoleucos Calidris canutus Tringa ochropus Gallinula chloropus Glareola pratincola Tringa totanus
STUDY AREA The Mancha Húmeda Biosphere Reserve (MHBR) is located in the upper basin of the Guadiana River (Central Spain).
Spring and summer populations.
Table 2. Guilds classification (in bold, species selected for study in detail) based in the classification from Gosálvez (2011)
Purpose: to analyze the changing communities of waterfowl species in the MHBR, from the point of view of metapopulation dynamics, as a critical goal in the planning for the conservation of species that live in these fragmented habitats, understanding that network management should prevail above that of isolated wetlands.
•
1)
Tadorna tadorna
Philomachus pugnax Calidris ferruginea Gallinago gallinago
Guild 4 (l. waders)
Guild 5 (l. touch)
Recurvirostra avosetta Himantopus himantopus Limosa limosa
Charadrius dubius Charadrius hiaticula Arenaria interpres Charadrius alexandrinus
Guild 9 (Air predators) Circus cynaeus Strategy 1 Strategy 2 Strategy 3
Gelochelidon nilotica Chlidonias hybridus Circus aeruginosus Chlidonias niger
Vanellus vanellus
Figure 1. Location of the study area Table 3. Population dynamics of selected birds. e represents the process of extinction, c colonization process and eq balance process
Table 1. Study wetlands
Study wetlands
Mancha Húmeda Biosphere Reserve
Wetland Alcahozo Camino de Villafranca Manjavacas Mermejuela Pajares Pedro Muñoz Quero Salicor Veguilla Yeguas
Area (ha) 72.94 136.37 244.20 9.62 22.52 54.50 150.79 47.87 70.73 67.04
Figure 2. Picture of Salicor wetland
METHODOLOGY •
Monthly censuses were conducted between October 2006 and October 2010, whose reliability was based on gregariousness and stability of species in wetlands.
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The most important characteristics of each species were described: distribution and population, habitat, status and conservation.
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Their metapopulation structures were analyzed:
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Structure type.
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Population and size relationships of wetlands.
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Isolation.
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Degree and type of neighborhood of populations.
In the analysis of metapopulation dynamics the Levins model was used. The survival viability of the selected species was calculated assuming the disappearance of a 20% of the habitats.
Recurvirostra avosetta
Species
R2
R
Podiceps nigricollis
0.19
1
Oxyura leucocephala
Type of Metapopulation Dynamic Metapopulat. Wetlands Extinction metapopulation size variation occupation at risk H c e eq Results the same time Classic
15
15
13
Stable
1/8
9
Medium
0.18 0.8
Classic
12
7
11
Positive
1/4
6
Low
Netta Ruffina
0.45 0.8
Classic
14
12
13
Positive
1/6
7
Low
Anas clypeata
0.61 0.9
Classic
19
18
17
Positive
1/7
10
Medium
Tadorna tadorna
0.9
0.9
Classic/Continent 24 island
23
18
Down
1/9
10
High
Phoenicopterus roseus
0.8
0.9
Classic
20
20
16
Stable
1/8
10
High
Recurvirostra avosetta
0.6
0.9
Classic
19
20
14
Down
1/8
10
High
Charadrius alexandrinus
0.6
0.9
Classic
15
14
12
Positive
1/4
10
Low
Actitis hypoleucos
0.4
1.1
Classic
8
9
6
Down
1/5
9
Low
Tringa totanus
0.6
1.1 Continent island
11
12
9
Stable
1/8
9
Medium
Anser anser
0.42 1.6
Continet
4
7
4
Down
1/2
3
Medium
Gelochelidon nilotica
0.06 0.9
Classic
9
8
9
Positive
1/7
9
Medium
Circus aeruginosus
0.7
Classic
15
13
14
Positive
1/6
10
Medium
0.9
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Almost all species analyzed had a classical metapopulation structure and most of them were positive. There was not a unique large population that secure the survival of all metapopulation.
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Habitat patches had high rates of dispersion (R values between 0.78-1.56).
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All wetlands were never inhabited by the same species at the same time.
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The risk of a 20% loss of habitats in the analyzed species can lead to the disappearance of the species.
CONCLUSIONS •
There is a wide variety and diversity of species, whose survival depends largely on maintaining the asynchronous functioning of the network of wetlands that sustains them.
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Species and registered individuals are concentrated in a few wetlands with larger size and availability of water.
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Asynchronous dynamic occupation occurs in wetlands according to habitat and water availability.
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The understanding of the dynamic metapopulation has a essential limitation very difficult to overcome: the "black boxes" or the influence of unknown waterfowl populations.
References: Gosálvez, R.U. 2011. Análisis biogeográfico de las lagunas volcánicas de la Península Ibérica. Bases científicas para su Gestión. PhD Thesis. Universidad de Castilla-La Mancha. Ciudad Real, Spain. This work has been funded by two projects from the Department of Environment (reference PREG05-016) and the Department of Education and Science (reference PAC06-0116-3683) of the Castilla-La Mancha regional Government. It has also been supported by a training scholarship of research staff from the Castilla-La Mancha regional Government.
