waterfowl-romano et al 2005

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O R I G I N A L P A P E R

Marcelo Romano Ignacio Barberis Fernando PaganoJuan Maidagan

Seasonal and interannual variation in waterbird abundanceand species composition in the Melincue saline lake, Argentina

Received: 3 November 2004 / Accepted: 4 January 2005 / Published online: 17 February 2005 Springer-Verlag 2005

Abstract We conducted 14 bird surveys in the Melincuesaline lake from 1992 to 2002 (7 in winter and 7 insummer), and we detected 223,643 individuals belongingto 71 species from 17 families. The more abundant

species were Fulica leucoptera, Larus maculipennis,Phoenicopterus chilensis, Plegadis chihi, Anas platalea,Himantopus mexicanus, and Rollandia rolland. Birdabundance was similar in winter and summer, whereasspecies composition differed between seasons. We re-corded 65 species in summer and 59 in winter.P. chilensis and A. sibilatrix were more abundant inwinter, whereas Ajaia ajaja, Phalacrocorax olivaceus,Ardea ibis, Sterna nilotica, Egretta thula, Mycteriaamericana, Charadrius collaris, A. versicolor, Calidrisfuscicollis, and Ciconia maguari were more abundant insummer. Bird abundance in each survey was positivelyassociated with the lake level. In summer surveys, the

highest variation in species composition through theyears was associated with water level fluctuations.Shorebirds predominated in those years with lower level,whereas the species that fed mainly on plants or verte-brates predominated in years with higher levels. Thosespecies that fed on invertebrates (not shorebirds) andthose that fed on invertebrates and plants predominatedin years with intermediate level. The omnivorous species

predominated in years of lower level. There were dif-ferences among transects in the proportion of differenttrophic groups. Short-term studies that do not take intoaccount the particular dynamic of these systems may

lead to erroneous generalisations. Thus, the long-terminformation of this study may be useful for managementand conservation of species and system.

Keywords Pampas Shallow lakes Waterfowlcensuses Wetlands

Introduction

Waterbird communities experience seasonal and annualfluctuations in abundance and species composition, on a

local (DuBowy 1988; Bethke 1991; Lo pez de Casenaveand Filipello 1995), as well as on a regional scale (Bethkeand Nudds 1995). Variations in bird abundance resultfrom population processes (i.e. birth and death rates), aswell as migration among habitats (Poulin et al. 1993).Bird abundance at a local scale depends on habitatcharacteristics (i.e. water body size and depth, and waterphysical and chemical conditions), the availability, dis-tribution and density of food, and the availability ofsuitable sites for reproduction or resting (Wiens 1989).Variations in species composition may be associatedwith the arrival of seasonal migratory species, togetherwith the presence of species dwelling in the area

(Filipello and Lo pez de Casenave 1993). Moreover,variations in habitat conditions may also producechanges in community species composition (Garca et al.1997; Caziani and Derlindati 2000). Seasonal or annualvariations are highly dependent on events like precipi-tation and general hydrological budget, whereas pluri-annual variations are dependent on regional or globalmacroclimatic events like ENSO.

In the Pampas plains of Argentina (one of the moremodified and anthropogenised regions of the world),wetlands represent highly complex environments

M. Romano (&) I. Barberis F. Pagano J. MaidaganCentro de Investigaciones en Biodiversidad y Ambiente (Ecosur),Pasaje Sunchales 329, 2000 Rosario, Santa Fe, ArgentinaE-mail: [email protected]: +54-341-4260177

I. BarberisFacultad de Ciencias Agrarias, Universidad Nacional de Rosario,Casilla de Correo 14, S2125ZAA Zavalla, Santa Fe, Argentina

I. BarberisCONICET, Argentina

F. PaganoFacultad de Ciencias Veterinarias, Universidad Nacionalde Rosario, Casilla de Correo 166, Bvd.Ovidio Lagos y Ruta 33, S2170HGJ Casilda,Santa Fe, Argentina

Eur J Wildl Res (2005) 51: 113DOI 10.1007/s10344-005-0078-z


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distributed within a highly simple matrix of agroeco-systems. As a consequence, these wetlands constitutesites where numerous bird species concentrate (Bucherand Herrera 1981; Blanco and Carbonell 2001). There isinformation about waterbirds of the pampas shallowlakes (Nores and Yzurieta 1980; Canevari et al. 1991).However, to our knowledge, temporal variation inwaterbird abundance and species composition associ-ated with these shallow lakes were only analysed in veryfew locations like Mar Chiquita Lake in Co rdoba(Bucher 1992; Bucher et al. 2000) and Encadenadas deChascomus Lakes in Buenos Aires (Vilches 2002).

The Melincue Lake is one of the main sites ofwaterbird concentration in the Humid Pampas (Blancoand Carbonell 2001). Nevertheless, there is no record ofany systematic study before the beginning of the cen-suses in 1991 (Blanco and Carbonell 2001). Therefore,the objectives of this study were (1) to assess seasonaland annual variations in abundance and species com-position of the waterbird community from the MelincueLake, and (2) to evaluate the relationship between theseobserved variations and water level fluctuations. This

basic information would be very useful to elaboratemanagement and conservation plans for the species inparticular and for the system in general.

Materials and methods

Study area

The study area is located in a highly agricultural region(c. 70% of the area), at the south of the Santa Fe province(Fig. 1). This region is known as pampas of the shallowlakes (Pasotti et al. 1984) because the geomorphology

has developed a large number of endorheic watershedswith several shallow lakes. Among them, the mostimportant is Melincue (3325S, 6128O; 84 m a.s.l.)with a maximum depth about 67 m (E. Peralta, personalcommunication) and free water span over 120 km2. Itswatershed comprises 678 km2 and is the final collector ofseveral wet meadows (can adas). The water is moder-ately saline (about 3 g/dm3 of total dissolved solids;Pasotti et al. 1984; Ecosur, unpublished data), with lowwater transparency (about 0.15 m with a Secchi disk;Quiro s 1988). Total phosphorus content was about7,912 mg/m3, total organic nitrogen was about 240 lMand total chlorophyll-a was about 5.7 mg/m3 (Quiro s1988). The particular water chemical composition may bepartially conditioned by the income of water from deepconfined water-tables, due to the location of the lake onthe Tostado-Selva-Melincue geofracture (Pasotti et al.1984), but this contribution was not evaluated yet.

Climate is temperate, subhumidhumid (Pasotti et al.1984). Mean annual temperature is 16C, and annualprecipitation averages 917 mm (period 19331990)concentrated in the summerautumn time (Biasatti et al.

1999). In the last 60 years, annual records have variedbetween 542 mm and 1,258 mm, which in turn hasmarked dry and wet cycles. Soils surrounding the lakehave halo-hydromorphic characteristics, with sodiumexcess and alkaline reaction (Lewis and Pire 1978).

Water level in Melincue Lake, like in other endorheicwetlands, experiences seasonal variations through theannual cycle, mainly conditioned by the balance givenby precipitation, evaporation and watershed runoff.However, the magnitude of these seasonal variations issmall when compared with cyclical pluriannual varia-tions that result from wet or dry macroclimatic cycles(ENSO) (Bucher 1992; Reati et al. 1997; Piovano et al.

Fig. 1 Location of the threesurvey transects (North, Eastand West transects) in theMelincue saline lake(Argentina). In the inset map,the dot shows the location ofthe study area

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2002). Throughout the XX century, these cycles synch-ronically affected other large wetlands of the Southeastof the Neotropical Region (e.g. Mar Chiquita Lake,Pantanal, Parana-Plata watershed) (Piovano et al. 2002).Through the last 20 years, two wet and two dry cycleswere recorded in Melincue. The first dry cycle was re-corded from the beginning of 1983 until 1990 with aminimum water level about 82.58 m a.s.l. in January1990. Then started a wet cycle that increased the waterlevel up to 85.26 m a.s.l. The second dry cycle, started atthe beginning of 1994 and ended in 1997, when the lakereached its minimum water level for the study period(83.62 m a.s.l.) (Biasatti et al. 1999). From then onstarted a new wet cycle that at the end of the studyperiod had increased the water level to 85.03 m a.s.l. andby June 2003 reached 86.13 m a.s.l. Water level varia-tions between cycles determine flooding area fluctua-tions that range about 4,0005,000 ha, whichapproximately represent 36% of the wetland area.

Vegetation is composed by herbaceous communities,prairies and steppes. The halophilous prairie is codom-inated by Distichlis spicata and Paspalum vaginatum. In

small ponds associated with the lake, there are juncalesof Schoenoplectus californicus and totorales of Typhadomingensis. In the neighbourhood of the lake there arepatches of chan ar (Geoffroea decorticans), espinillo(Acacia caven) and cina-cina (Parkinsonia aculeata)(Lewis and Pire 1978). In the lake, aquatic vegetation(large size algae and macrophytes) is scarce or almostabsent (Biasatti et al. 1999).

The fauna is very diverse (Romano 1999). Numerousmigrant and resident bird species use this wetland as aresting and feeding area (Blanco and Canevari 1994,1995; Blanco et al. 1996; Romano et al. 1996; Canevariet al. 1998). Fishes are scarce despite the size of the lake

and are mainly located in the shore areas associated withthe income of rainwater (Biasatti et al. 1999). In theseshallow waters, trophic chains are more complex than indeeper areas (Biasatti et al. 1999). The limnology of thelake is almost unknown.

Geomorphology, soils, and climate, as well as humanactivity (agricultural intensification, and road and urbandevelopment) have conditioned the system dynamicthrough the last century. The lake has experiencedrecurrent and strong oscillations in the water level,producing large alterations on the ecosystem that im-pacted, and still impact, on the lake surrounding areasand the infrastructure linked to them (e.g. farmlands,

roads, towns, etc.), as well as on the associated com-munities (Peralta et al. 2001).

Methods

Waterbird abundance and species compositionin the Melincue Lake

Fourteen bird censuses were carried out from 1992 to2002 (7 in winter: JulyAugust and 7 in summer:

FebruaryMarch). In each census, all birds presentalong three transects were counted and identified tospecies level using binoculars (10) or Spotting scopes(15/45) and manual counters. For species identifica-tion, Narosky and Yzurieta (1989) field guide wasused. The transects (i.e. walking lines parallel to thecoast) were travelled by vehicle, boat and foot. Theycomprised different environments: (a) Dry grasslands(including farmlands), (b) Shallow water (includingflooded grasslands), (c) Muddy shore (with and with-out vegetation) and (d) Open water. A maximumobservation distance of 500 m from the central line ofeach transect was set out arbitrarily by using a1,000 yard rangefinder. Transects differed in theirlength (range 8.0011.25 km) and complexity (i.e.environmental diversity). In winter 1995, the length ofthe transects was reduced due to flooding problems. Inwinter 1992 and summers 1993 and 1997, the northerntransect was not censused. In 1998, 2000 and 2001,censuses were not carried out in either season. Foreach census, systematic records of the water level wereused (Biasatti et al. 1999; E. Peralta and M. Luppi,

unpublished data).For the genus Calidris, Larus, Tringa and for some

ducks, herons, terns, and plovers, sometimes it was notpossible to identify all individuals to the species level dueto their similarity and their large numbers. In eachcensus, in order to estimate different indexes, doubtfulindividuals were proportionally allocated to each ob-served species according to their abundance (Bucher andHerrera 1981).

Species were grouped in five trophic groups accordingto the consumed items: P=plants (i.e. plants and seeds),F=Plankton (Filter-feeders; this group comprised fla-mingosPhoenicopterus spp.- and spoonbillsA. ajaja),

V=vertebrates (e.g. fishes, batracians, reptiles, birds,rodents), O=omnivores, and I=invertebrates (e.g.insects, molluscs and crustacea). Within the latter, wedistinguished shorebirds (I-S), from those birds that gettheir food from other environments (I-O). Speciesallocation to different trophic groups was based onCanevari et al. (1991), and personal observations.Wetlands International (2002) was followed for scientificnomenclature.

Seasonal variation in waterbird abundanceand species composition

In order to evaluate the relative importance of eachspecies, we modified an index proposed by Bucher andHerrera (1981) that take into account the relativeabundance of each species and the number of censusesin which it was recorded (See Appendix 1). This indexwas estimated for winter, summer and both-seasoncensuses.

Seasonal differences in the number of individuals/km were analysed with a Generalized Linear Modelassuming a Poisson probability distribution of the

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response variable (Quinn and Keough 2002). As cen-suses were carried out on the same transects for eachseason, transects (nested within each census) wereconsidered subjects in the repeated measures analysis.The length of the transects was used as a covariate.Analyses were carried out using the GENMOD pro-cedure of the SAS statistical programme (SAS Insti-tute Inc. 1999).

Seasonal differences in species richness were com-pared using rarefaction curves (standardized speciesrichness). This method allows estimation of the expectedspecies richness from randomized subsamples of indi-viduals in a census (Gotelli and Graves 1996). Curveswere constructed by calculating the average speciesrichness value from random samples of increasingabundance, with 1,000 iterations for each abundancelevel, using the EcoSim program (Gotelli and Entsmin-ger 2002). The program estimates a 95% confidenceinterval for every average species richness value. Varia-tions in species composition among years for each sea-son were estimated using the -diversity index(Whittaker 1967).

Differences in species composition between seasonswere evaluated with the multiple response permutationprocedure (MRPP) of the PC-ORD program (McCuneand Mefford 1999). This non-parametric method has theadvantage of not requiring the assumptions of multi-normality and homogeneity of variance. The Srensenindex was used as a dissimilarity measure.

Species association with either winter or summercensuses was analysed using the Indicator Value Anal-ysis from the PC-ORD program (McCune and Mefford1999). This method combines information on the con-centration of species abundance in a particular group(i.e. season) and the faithfulness of occurrence of a

species in a particular group (i.e. season). Then it cal-culates indicator values for each species in each season,which are tested for statistical significance using a MonteCarlo technique. A value was considered significantwhen P


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and similar between seasons (b-diversity: winter=1.63;summer=1.57).

Species composition differed between seasons (MRPPtest: T=2.64, P=0.012). Sixty-five species were re-corded in summer and 59 in winter (Appendix 2). Twospecies were almost restricted to winter (P. chilensis andA. sibilatrix) and ten to summer (A. ajaja, P. olivaceus,Ardea ibis, Sterna nilotica, Egretta thula, M. americana,C. collaris, A. versicolor, Calidris fuscicollis, and Ciconiamaguari) (Monte Carlo test for species indicator valueP


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In summer, the highest variation in species compo-sition among surveys throughout the study period (CAAxis I Eigen value=0.405) was related to variations inwater level (r=0.63, P=0.003), whereas the secondaxis (Eigen value=0.253) discriminated surveysaccording to the transects (Fig. 5). The first axis dis-criminated the species according to their trophic groups(H=24.18, 6 df, P


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Seasonal variation in waterbird abundanceand species composition

Waterbird abundance in Melincue fluctuated markedlythrough the 10-year study period, but there were nosignificant differences in bird abundance between sea-sons. That may be related, on the one hand, to a mildwinter, in contrast to wetlands located at higher latitudes(De la Balze and Blanco 2002) or at higher altitudes(Caziani et al. 2001), and on the other hand, to the ob-served association of bird abundance and water level(See Sect 4.3).

The lower winter species diversity may be related, onthe one hand, to a lower species richness, and on theother hand, to a lower evenness, because a few species(P. chilensis, L. maculipennis and F. leucoptera) con-centrated about 60% of the individuals. It is worthnoting that these species do not overlap in their trophicniches (P. chilensis (filter-feeder), L. maculipennis(omnivore) and F. leucoptera (herbivore)). In summer,the three species with higher relative importance con-centrated fewer than 30% of the individuals, thus a

higher niche overlap would be expected. Even thoughthe results in this waterbird community suggest thatresource competition may be higher in winter than insummer (DuBowy 1988), a final conclusion cannot beformulated because resource abundance was not analy-sed.

Differences in species composition between seasonsmay be related to a seasonal species replacement due tothe latitude where the wetland is located. Species thatspend summertime at higher latitude like Patagonia (e.g.C. modestus, C. falklandicus, Theristicus melanopsis andA. sibilatrix) or at higher altitude like the Andean Alti-plano (e.g. P. andinus) arrive to the site at the beginning

of winter, and in turn, an exodus to the north is observedfor those species that spend summertime in the area.Some species (e.g. A. ajaja and M. americana) migratetoward lower latitudes of the Neotropical Region,whereas other species (e.g. Pluvialis dominica, T. mela-noleuca, T. flavipes, Calidris canutus, Calidris melanotos,Calidris bairdii, Calidris fuscicollis, Limosa haemastica,Micropalama himantopus and Phalaropus tricolor) mi-grate toward the Neartic Region. Similar results wereobserved in the Mar Chiquita Lake (Bucher and Herrera1981) and in the coastal zone of Ro Negro, Argentina(Gonza lez 1996). Although some of these species wereobserved throughout the year, the highest proportion

was observed in summer (e.g. Phalaropus tricolor and T.melanoleuca). In the case of P. andinus, even thoughsome individuals were recorded during some summercensuses, the highest proportion was observed in winter,thus it may be classified as a winter visitor, matchingobservations in Mar Chiquita (Bucher 1992; GCFA2001). Calidris bairdiideserves a special comment; for, inspite of being considered a summer visitor (Canevariet al. 1991), it presented a higher proportion of indi-viduals in winter.

Some species considered residents, showed importantvariations in their numbers between seasons(e.g. P. chilensis more important in winter; R. rolland,E. thula, Ardea ibis, N. peposaca, P. olivaceous, Cosco-roba coscoroba, A. versicolor, Stena nilotica, Ciconiamaguari, Nycticorax nycticorax, C. collaris and Dendr-ocygna bicolor more important in summer). That may beassociated with their reproductive habits (concentrationor dispersion according to the season), with the use ofthe environments at a higher spatial scale (lake sys-tems), or because at least part of the population travelsto other areas (Bucher and Herrera 1981; Simmons2000; GCFA 2001; Menegheti and Dotto 2002).

In Melincue , most species with higher relativeimportance (F. leucoptera, P. chihi, L. maculipennis andH. mexicanus) did not show significant differences inabundance between seasons. That contrasts with theresults showed by Blanco and Carbonell (2001) for otherplaces. In our study, P. chilensis was the only importantspecies that showed marked seasonal variations. Nev-ertheless, contrary to what happens in two of the mostimportant sites in Argentina for this species, such as Mar

Chiquita saline lake and Llancanelo shallow lake (Bu-cher 1992; Bucher et al. 2000; H. Sosa, personal com-munication), the higher abundance was observed inwinter. The summer of 1999 deserves special mention,when that species showed a high number of individuals(1,807 adults) matching the only successful reproductiveevent (400/500 nestlings) recorded during the studyperiod.

Seasonal variation in trophic group abundances maybe related to migration patterns due to food availabilityor reproductive behaviour. For instance, the higherproportion of species that fed on vertebrates andinvertebrates, either shorebirds or not, in summer than

in winter was probably associated with higher foodavailability. In contrast, higher abundance of filter-feeders in winter than in summer was probably related tothe reproductive behaviour of the main species.

Relationship between water level and waterbirdabundance and species composition

Water level variations influence the physical, chemical,and biological characteristics of a wetland (Garca et al.1997; Piovano et al. 2002), determining the higher orlower availability of suitable environment for feeding,

reproduction, and/or resting, as well as nutrient avail-ability; conditioning in turn bird abundance (Bucheret al. 2000; Keddy 2000). In Melincue, a positive asso-ciation between water level and bird abundance wasobserved. That may be related to the fact that increasingthe water income to the system, increases on the onehand, the income of allochtonous nutrients, producingan increment in species richness (phyto and zooplank-ton, invertebrates, fishes, etc.) (Garca et al. 1997; Bu-cher et al. 2000), and on the other, increases the area of

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some important environments for birds (e.g. floodedgrasslands, shallow water and open water) (M. Romanoet al., unpublished data). This is coincident with theresults from Cezilly et al. (1995) in the Camargue(France), Garca et al. (1997) in Fuente de Piedra Lake(Spain), and with the results from Lopez de Casenaveand Filipello (1995) for the Reserva Costanera Sur(Argentina). In contrast, Scott and Carbonell (1986 citedby Reati et al. 1997) showed a reduction in bird abun-dance when shore environments disappeared due to anincrease in water level. Similar observations were doneby Johnsgard (1956) for a group of wetlands in the stateof Washington (USA) and by Bucher (1992) in MarChiquita Lake (Argentina), where an increase in waterlevel caused that the shoreline be in contact with theshrubby vegetation, and therefore suitable environmentsfor waterbirds disappeared.

As additional information for Melincue , it is worthnoting that a census carried out in winter 2003 (waterlevel 86.10 m a.s.l.) resulted in 39,284 observed indi-viduals, from a survey of only 50% of the area. Thisresult is the highest observed abundance for all censuses

and matches the highest water level recorded in the last60 years (86.10 m a.s.l.).

Species richness and diversity are associated with re-source availability and with environmental heterogene-ity (Keddy 2000). Filipello and Lo pez de Casenave(1993) observed a reduction in species number anddiversity coincident with the reduction of the floodedarea. In Melincue , there was no correlation betweenwater level and species number or diversity for waterlevel above 84 m a.s.l. However, in the only surveycarried out when the water level was below 84 m bothdeclined abruptly. That may be associated with the areareduction of some important environments for several

species (e.g. flooded grassland) (Romano et al. unpub-lished data), as well as an increase of salt content and theconsequent modification of the aquatic community(plankton, vegetation, fishes, etc).

Numerous studies recorded a positive associationbetween variations in water level of a wetland and theabundance of different waterbird guilds (Amat 1981,1984 cited in Filipello and Lo pez de Casenave 1993;Bethke and Nudds 1995). In saline wetlands, the waterlevel is inversely correlated with the salt concentration.That in turn conditions the bird abundance by affectingthe presence, abundance, and/or diversity of food re-sources (e.g. fishes, submerged macrophytes, inverte-

brates, algae, etc) (Garca et al. 1997; Reati et al. 1997;Bucher et al. 2000). In Melincue , in high water-levelyears, the relative increase of those species that fed onplants, vertebrates and invertebrates, except shorebirds,may be related to the change in the chemical composi-tion of water (salinity reduction) and to the increase ofshallow water areas and flooded grasslands, which inturn favours an increase in the population of the plantsand prey species (e.g. fishes, batrachians, invertebrates,etc). This pattern matches the results observed by Me-negheti and Dotto (2002) for ducks in Brazil. Likewise,

the relative increase of shorebirds in low water levelyears may be associated with a higher availability ofsuitable environments (mud shores) (Bucher and Her-rera 1981; Amat 1984 cited by Filipello and Lopez deCasenave 1993), as well as with the availability of foodresources, because the larvae of some diptera which theyfeed on can tolerate high levels of salinity (Reati et al.1997). The relative increase of the omnivores, mainly L.maculipennis and L. cirrocephalus, in those years maynot be related to the increase of the availability ofenvironments or food resources, but to a large amplitudeof their trophic spectrum and to their opportunisticbehaviour, which allows them to use allochtonous re-sources (Canevari et al. 1991), while using Melincue as aresting site (M. Romano et al., unpublished data).

The abundance of flamingos (filter-feeders) is notassociated with water level. Even though out of thisstudy, is interesting to mention that surveys carried outduring winter 2003 (water level 86.10 m a.s.l.) showed adrastic reduction in the abundance of both flamingospecies (391 individuals of Ph. chilensis and no individ-ual of Ph. andinus). This pattern matches the results of

several studies carried out in Mar Chiquita Lake (Bu-cher 1992; Martnez 1995; Bucher et al. 2000). That largevariation in abundance may be related to a nomadicopportunistic behaviour conditioned by resource avail-ability, with the effect that, when facing unfavourableenvironmental conditions (e.g. drought or flood), birdswould change their displacement pattern at a regionallevel, seeking better quality sites (Johnsgard 1956;Baldassarre and Arengo 2000; Tuitte 2000; Meneghetiand Dotto 2002; S. Caziani et al., in preparation). Bydirectly affecting the amount, quality, and availability ofresources (e.g. food and habitat) (DuBowy 1988; Garcaet al. 1997), the water level might be strongly influencing

the habitat suitability for these species. Nevertheless, inorder to determine the causes, these aspects should bestudied in greater depth.

Differences in trophic group abundances amongtransects may be associated with differences in envi-ronmental complexity (i.e. proportion of different envi-ronments), in disturbance intensity (i.e. proximity toroads and urban areas), or in their resilience to waterlevel variation. Moreover, the total availability of dif-ferent environments is expected to change with annualand decadal variation in precipitation (Boyle et al.2005). These observations deserve more study.

Conservation

Large wetlands, such as Melincue shallow lake, repre-sent sites of high importance for biodiversity conserva-tion, mainly by being immersed in highly modifiedecosystems, like the agroecosystems of the HumidPampas. In the last years, a great number of canalizationand drainage works have let agriculture spread overseveral wetlands of the region, producing a drasticreduction in heterogeneity at the landscape level, and

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therefore, its biodiversity. A proper hydrological man-agement needs to know in depth the physical and bioticfactors of the system and in particular, the differentphases of the water cycle (i.e. precipitation, absorption,runoff, evapotranspiration and infiltration in large re-gions and for long periods) (Canevari et al. 1999), takinginto account the long-term cycles that dictate its dy-namic. In the case of Melincue , that is particularlyimportant, because the results presented in this papershow a high correlation between the water level and theabundance and species composition of the waterbirdcommunity, and reinforce the information presented byBlanco and Canevari (1994, 1995), Blanco et al. (1996),Canevari et al. (1999), Blanco and Carbonell (2001) andRomano et al. (2002), demonstrating the great impor-tance that this wetland has from the conservationviewpoint.

This wetland meets three of the RAMSAR conven-tion criteria. Melincue is one of the two known plainwetlands of Argentina, that sustains large populations ofP. andinus in its winter distribution area (Blanco andCarbonell 2001; GCFA 2001; Romano et al. 2002). This

species is considered as the rarest of the five flamingospecies in the world (Rose and Scott 1994), classified bythe IUCN as Vulnerable (Wetlands International 2002),and included in the Appendix 1 of the convention ofmigratory species (CMS) (Groombridge 1994; Johnson1995, 1996). That supports its fully inclusion under thesecond criterion of the RAMSAR convention (Con-vencio n de Ramsar 1996). Moreover, this wetland holdsin winter a variable number that includes between 5%and 7% of the estimated world population of P. andinus(Blanco and Carbonell 2001; GCFA 2001; Romanoet al. 2002). That justifies its inclusion under the sixthcriterion of the Convention (Convencio n de Ramsar

1996). In addition, the results of the NeotropicalWaterbird Census (Blanco and Canevari 1994, 1995;Blanco et al. 1996; Canevari et al. 1998; Blanco andCarbonell 2001) justify the inclusion of the wetlandunder the fifth criterion of the Convention (Convencionde Ramsar 1996). In addition, P. chilensis, Coscorobacoscoroba, Ciconia maguari, Podiceps major, R. rolland,

L. dominicanus, A. georgica, A. platalea, F. leucoptera,Nycticorax nycticorax and P. olivaceus use the wetlandarea for their reproduction (M. Romano et al., unpub-lished data).

Although the wetland is protected as a Multiple UseProvincial Reserve (Reserva Provincial de Usos Multi-ples), it does not have an effective implementation, so itsconservation faces several potential risks. It would behighly recommendable to implement a strategic man-agement plan that secures its effective conservation inthe future and to include this wetland in the RAMSARsite list for Argentina.

Acknowledgements We greatly appreciate the collaboration fromMarcelo Luppi, Eduardo Pire and Ernesto Micol for their help inthe field. We thank Luis Amestoy, Alfredo Jorro and Carlos On-tivero Campo for field facilities during the censuses, the agriculturalcompanies La Tehuelche, El Pedernal and Laguna San Carlos forallowing us to get into their properties, and Sandra Caziani andJohn Middleton for critically reading the manuscript. We declarethat the surveys comply with the current Argentinian laws.

Appendix 1

Relative importance index

In order to estimate the relative importance index, wemodified an index proposed by Bucher and Herrera(1981) using the following equation:

RI Ni=Nt Ci=Ct 100;

where Ni is the total number of recorded individuals ofspecies i through the whole study period, Nt is the totalnumber of individuals of all species through the wholestudy period, Ci is the number of censuses where indi-

viduals of species i were observed, and Ct is the totalnumber of censuses

Appendix 2

Table a

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References

Amat J (1981) Descripcio n de la comunidad de patos del ParqueNacional de Don ana. Don ana Acta Vertebrata 8:125158

Amat J (1984) Las poblaciones de aves acua ticas en las lagunasandaluzas: composicio n y diversidad durante un ciclo anual.Ardeola 31:6179

Baldassarre GA, Arengo F (2000) A review of the ecology andconservation of Caribbean flamingos in Yucata n, Mexico.

Waterbirds 23:7079Bethke RW (1991) Seasonality and interspecific competition inwaterfowl guilds: a comment. Ecology 72:11551158

Bethke RW, Nudds TD (1995) Effects of climate change and landuse on duck abundance in Canadian prairie-parklands. EcolAppl 5:588600

Biasatti N, Delannoy L, Peralta E, Pire E, Romano M, Torres G(1999) Cuenca Hidrogra fica del Humedal de la Laguna Melin-cue , Provincia de Santa Fe. ProDIA, SRNyDS, Buenos Aires

Blanco DE, Canevari P (eds) (1994) Censo Neotropical de AvesAcua ticas 1993. Humedales para las Ame ricas (WA), BuenosAires

Blanco DE, Canevari P (eds) (1995) Censo Neotropical de AvesAcua ticas 1994. Humedales para las Ame ricas (WA), BuenosAires

Blanco DE, Carbonell M (2001) El Censo Neotropical de avesacua ticas. Los primeros 10 an os: 19901999. Wetlands Inter-national, Buenos Aires and Ducks Unlimited Inc Memphis

Blanco DE, Minotti P, Canevari P (1996) Exploring the value ofthe neotropical waterbird census as a conservation and wildlifemanagement tool. Report to Canadian Wildlife Service, LatinAmerican Program. Humedales InternacionalAmericas,Buenos Aires

Boyle TP, Caziani SM, Waltermire RG (2005) Landsat TMinventory and assessment of waterbird habitat in the southernaltiplano of South America. Wetland Ecology and Management(in press)

Bucher EH (1992) Population and conservation status of flamingosin Mar Chiquita Co rdoba, Argentina. Colonial Waterbirds15:179184

Bucher EH, Herrera G (1981) Comunidades de aves acua ticas de lalaguna Mar Chiquita (Co rdoba, Argentina). Ecosur 8:91120

Bucher EH, Echevarra AL, Juri MD, Chani JM (2000) Long-termsurvey of Chilean flamingo breeding colonies on Mar ChiquitaLake, Co rdoba, Argentina. Waterbirds 23:114118

Canevari M, Canevari P, Carrizo GR, Harris G, Rodrguez MataJ, Straneck RJ (1991) Nueva gua de las aves argentinas. Fun-dacio n Acindar, Buenos Aires

Canevari P, Blanco DE, Bucher EH, Castro G, Davidson I (eds)(1998) Los Humedales de la Argentina: Clasificacio n, Situacio nActual, Conservacio n y Legislacio n. Wetlands InternationalPubl 46, Buenos Aires

Canevari P, Blanco DE, Bucher EH (eds) (1999) Los beneficios delos humedales de la Argentina. Amenazas y propuestas de so-luciones. Wetlands International, Buenos Aires

Caziani S, Derlindati EJ (2000) Abundance and habitat of HighAndes flamingos in Northwestern Argentina. Waterbirds23(Spec publ 1):121133

Caziani SM, Derlindati EJ, Ta lamo A, Sureda AL, Trucco CE,

Nicolossi G (2001) Waterbird richness in Altiplano wetlands ofNorthwestern Argentina. Waterbirds 24:103117

Ce zilly F, Boy V, Green RE, Hirons GJM, Johnson AR (1995)Interannual variation in greater flamingo breeding success inrelation to water levels. Ecology 76:2026

Convencio n de Ramsar (1996) Manual de la Convencio n deRamsar: Una gua a la Convencio n sobre los Humedales deImportancia Internacional (Davis TJ, Blasco D, Carbonell M).Oficina de la Convencio n de Ramsar, Gland

De la Balze V, Blanco DE (2002) El cauque n colorado (Chloephagarubidiceps): una especie amenazada por la caza de avutardas.In: Blanco DE, Beltra n J, De la Balze V (eds) Primer Taller

sobre la caza de aves acua ticas: hacia una estrategia para el usosustentable de los recursos de los humedales. Wetlands Inter-national, Buenos Aires, pp 119122

DuBowy PJ (1988) Waterfowl communities and seasonal environ-ments: temporal variability in interspecific competition. Ecol-ogy 69:14391453

Filipello AM, Lo pez de Casenave J (1993) Variacio n estacional dela comunidad de aves acua ticas de la Reserva Costanera Sur.Rev Mus Arg Cs Nat B Rivadavia Ecologa 4:115

Garca CM, Garca-Ruiz R, Rendo n M, Xavier Niell F, Lucena J(1997) Hydrological cycle and interannual variability of the

aquatic community in a temporary saline lake (Fuente de Pie-dra, Southern Spain). Hydrobiologia 345:131141

GCFA (2001) Priority actions for the conservation of high AndesFlamingos. Final Report for the Convention on MigratorySpecies (CMS). Grupo para la Conservacio n de FlamencosAltoandinos y Fundacio n Pachamama. CMS, Bonn

Gonza lez PM (1996) Habitat partitioning and the distribution andseasonal abundances of migratory plovers and sandpipers inLos A lamos, Ro Negro, Argentina. In: Hicklin P (ed) Shore-bird ecology and conservation in the Western Hemisphere 8.International Wader Studies, Ottawa, pp 93102

Gotelli NJ, Entsminger GL (2002) EcoSim: null models softwarefor ecology, version 7. Acquired Intelligence Inc and Kesey-Bear,Burlington

Gotelli NJ, Graves GR (1996) Null models in ecology. SmithsonianInstitution Press, Washington

Groombridge B (1994) IUCN red list of threatened animals.IUCN, Cambridge

Johnsgard PA (1956) Effects of water fluctuation and vegetationchange on bird populations, particularly waterfowl. Ecology37:689701

Johnson AR (1995) Annual Reports 19911994. Newsletter N7.IWRB Flamingo Specialist Group

Johnson AR (1996) WI/SSC Flamingo Specialist Group. SpeciesNewsletter of the Species Survival Commission. In: McCane E,Howes C, Nelson K (eds) IUCN 124

Keddy PA (2000) Wetland ecology: principles and conservation.Cambridge University Press, Cambridge

Lewis JP, Pire EF (1978) Suelos y Vegetacio n. In: Rasgos geolo g-icos y geomorfolo gicos de la laguna Melincue . Instituto deFisiografa y Geologa Dr Alfredo Castellanos. UNR Edi-tora, Rosario

Lo pez de Casenave J, Filipello AM (1995) Las aves acua ticas de laReserva Costanera Sur: cambios estacionales en la composicio nespecfica y en la abundancia de poblaciones y gremios. Horn-ero 14:914

Martnez DE (1995) Changes in the ionic composition of a salinelake, Mar Chiquita, province of Co rdoba, Argentina. Int J SaltLake Res 4:2544

McCune B, Mefford MJ (1999) Multivariate analysis of ecologicaldata. MjM Software, Gleneden Beach

Menegheti JO, Dotto JC (2002) Regulaciones de caza en RioGrande do Sul y resultados de los monitoreos de ana tidos:acuerdos y controversias. In: Blanco DE, Beltra n J, De la BalzeV (eds) Primer Taller sobre la caza de aves acua ticas: hacia unaestrategia para el uso sustentable de los recursos de los hume-dales. Wetlands International, Buenos Aires, pp 5966

Narosky T, Yzurieta D (1989) Gua para la identificacio n de las

aves de Argentina y Uruguay. Asociacio n Ornitolo gica delPlata, Va zquez Mazzini Editores, Buenos Aires

Nores M, Yzurieta D (1980) Aves de ambientes acua ticos deCo rdoba y centro de Argentina. Sec Agr Ganad Co rdoba,Co rdoba, Argentina

Passotti P, Albert O, Canoba C (1984) Contribucio n al conocimi-ento de la laguna Melincue . Instituto de Fisiografa y GeologaDr. Alfredo Castellanos, Publ 66. UNR Editora, Rosario

Peralta E, Romano M, Delannoy L, Biasatti NR (2001) Manejointegrado de cuencas hidrogra ficas. Caso de estudio: La la-guna Melincue , Problema tica y Perspectivas. Ambiental 4:90105

12


13/13

Piovano EL, Ariztegui D, Damatto Moreiras S (2002) Recentenvironmental changes in Laguna Mar Chiquita (centralArgentina): a sedimentary model for a highly variable salinelake. Sedimentology 49:13711384

Poulin B, Lefebvre G, McNeil R (1993) Variation in bird abun-dance in tropical arid and semi-arid habitats. Ibis 135:432441

Quinn GP, Keough MJ (2002) Experimental design and dataanalysis for biologists. Cambridge University Press, Cambridge

Quiro s R (1988) Relationships between air temperature, depth,nutrients and chlorophyll in 103 Argentinian lakes. Verh In-ternat Verein Limnol 23:647658

Reati GJ, Florn M, Ferna ndez GJ, Montes C (1997) The Lagunade Mar Chiquita (Co rdoba, Argentina): a little known, secu-larly fluctuating, saline lake. International J Salt Lake Res5:187219

Romano M (1999) Unidad de Planificacio n Estrate gica y Gestio nAmbiental de la Cuenca Hidrogra fica del Humedal de la La-guna Melincue (Santa Fe, Argentina). Technical Report, BID-SRNyAH, Buenos Aires

Romano M, Pagano F, Biasatti N, Pire E (1996) Ana lisis Prelim-inar de Cinco An os de Censos de Avifauna en la LagunaMelincue . In: Proceedings of the IX Argentine OrnithologicalMeeting. Asociacio n Ornitolo gica del Plata, Buenos Aires

Romano M, Pagano F, Luppi M (2002) Registros de Parina grande(Phoenicopterus andinus) en la laguna Melincue , Santa Fe,Argentina. Nuestras Aves 43:1517

Rose PM, Scott DA (1994) Waterfowls population estimates, 2ndedn. Wetlands International Publication 44, Wageningen

SAS Institute Inc (1999) SAS System version 8. SAS Institute Inc.,Cary

Scott DA, Carbonell MC (eds) (1986) Directory of Neotropicalwetlands. IUCN, Cambridge and IWRB Slimbridge

Simmons RE (2000) Declines and movements of lesser flamingos inAfrica. Waterbirds 23 (Spec publ 1):4046

Tuitte ChH (2000) The distribution and density of lesser flamingosin East Africa in relation to food availability and productivity.Waterbirds 23 (Spec publ 1):5263

Vilches A (2002) Monitoreo de poblaciones de ana tidos en la la-guna de Chascomus en la provincia de Buenos Aires. In: BlancoDE, Beltra n J, De la Balze V (eds) Primer Taller sobre la cazade aves acua ticas: hacia una estrategia para el uso sustentablede los recursos de los humedales. Wetlands International,Buenos Aires, pp 109112

Wetlands International (2002) Waterbird population estimates, 3rdedn. Wetlands International Global Series N 12, Wageningen

Whittaker RH (1967) Gradient analysis of vegetation. Biol Rev42:207264

Wiens JA (1989) The ecology of bird communities. CambridgeUniversity Press, Cambridge

Zar JH (1999) Biostatistical analysis, 4th edn. Prentice Hall Inc.,Upper Saddle River

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