Waders (Aves, Charadriiformes) in a Mediterranean remnant wetland: a year-round pilot study evidences contrasting patterns in diversity metrics

Abstract

-Around a yearly cycle (August 2011 -July 2012), we studied the assemblages of waders (Aves Charadriiformes) occurring in a Mediterranean remnant wetland, obtaining a set of diversity metrics. Mean total abundance shows a complementary pattern when compared to species richness and diversity: the highest values of mean total abundance were observed in December-January, due to high dominance of only one very abundant and gregarious species (the lapwing Vanellus vanellus). On the contrary, in this period, species richness and diversity showed the lowest values. These last metrics were highest in values during the April-September period when a large number of species of conservation concern utilize muddy areas as trophic and stop-over sites, due to the seasonal water stress. The highest values in species turnover index were observed between December-January and February-March when passage migrants (high richness, low abundance) substitute the wintering species (low richness, high abundance). Our data highlight that, in Mediterranean remnant wetlands, strategies should be addressed to increase the muddy suitable areas in the April-September period in order to maximize species richness and diversity. In fact, in these months these habitats host pre-and post-breeding migrant waders of conservation concern.Key words: Abundance, species richness, diversity, species turnover, Vanellus vanellus.Riassunto -Limicoli (Aves, Charadriiformes) in una zona umida mediterranea: uno studio pilota annuale evidenzia andamenti contrastanti nelle metriche di diversità.Durante il ciclo annuale agosto 2011 -luglio 2012 sono state studiate le comunità di caradriformi (Aves Charadriiformes) presenti in una zona umida mediterranea, ottenendo una serie di metriche di diversità. L'abbondanza totale media mostra un andamento complementare se confrontata con la ricchezza di specie e la diversità: i valori più alti dell'abbondanza media totale sono stati rilevati in dicembre-gennaio, a causa della elevata dominanza di una sola specie molto abbondante e gregaria (pavoncella Vanellus vanellus). Al contrario in questo periodo ricchezza e diversità hanno mostrato i valori più bassi. Queste ultime metriche hanno mostrato i valori più elevati nel periodo aprile-settembre, quando un gran numero di specie di interesse conservazionistico utilizzano le ripe fangose come sito trofico e di stop-over, anche a causa dello stress idrico stagionale. I valori più alti dell'indice di turnover sono stati osservati tra dicembre-gennaio e febbraio-marzo, quando le specie di passo migratorio (con alta ricchezza e bassa abbondanza) sostituiscono le specie svernanti (con bassa ricchezza e alta abbondanza). Questi dati sottolineano come, in aree umide residuali del Mediterraneo, le strategie di conservazione devono essere indirizzate verso un incremento delle ripe fangose idonee nel periodo aprile-settembre, al fine di massimizzare la ricchezza di specie e la diversità. Infatti, proprio in questi mesi questi habitat ospitano caradriformi di interesse conservazio...

Comparing habitat preferences of a set of waterbird species wintering in coastal wetlands of North Africa: implication for management

“…at this time of the year, especially during and after periodic flooding, floodplain meadows provide feeding grounds for these birds; they were often observed eating small invertebrates picked out of meadows, mudflat or exposed soil. Most of these species have declined significantly in recent years and are now classified as 'of conservation concern' (Battisti et al, 2015). This guild undergoes the previous scenario, it comprised specialist species that were highly concentrated in small area (FLM represents 11.34% of the wetland surface) and have an increasing niche overlaps, which could render them more prone to habitat fluctuations and interspecific competitions.…”

“…3). Several studies suggested that floodplain meadows provide a rich habitat for a range of shorebirds and other long-legged wading birds throughout the wintering season, particularly where there are areas of scrub or hedgerows on the drier ground (Brazner, Hoffman, 1991;Burger et al, 1997;Battisti et al, 2015). at this time of the year, especially during and after periodic flooding, floodplain meadows provide feeding grounds for these birds; they were often observed eating small invertebrates picked out of meadows, mudflat or exposed soil.…”

“…Strategies promoted by wetland practitioners should be addressed to increase suitable meadows and muddy areas that are the second important habitat categories of the wetland, when a large number of waders occur during the migratory pass, in order to increase richness and diversity of these rare and declining species of conservation concern (e.g., included in annex 1 of 79/409/cEE and 147/2009/cE 'Birds'Directives: BirdLife international, 2004; Battisti et al, 2015).…”

Vertebrates in the “Palude di Torre Flavia” Special Protection Area (Lazio, central Italy): an updated checklist

“…Pluvialis squatarola (Linnaeus, 1758) M irr, W irr Lorenzetti & Taffon, 2007;Battisti et al, 2009a;Malavasi et al, 2009aMalavasi et al, , 2009bBattisti et al, 2012a;Battisti, 2014b;Battisti et al, 2015a Pluvialis apricaria (Linnaeus, 1758) M irr, W irr Max 150, 7.2.2004, R. Gildi, V. Dundee; W reg in the neighbouring areas (Macchiatonda); Battisti et al, 2015aBattisti et al, , 2016a Eudromias morinellus (Linnaeus, 1758) A 23.9.2005, M. Biondi, R. Gildi; Charadrius hiaticula Linnaeus, 1758 M reg, W irr Battisti et al, 2009a;Malavasi et al, 2009aMalavasi et al, , 2009bBattisti et al, 2015aBattisti et al, , 2019b Charadrius dubius Scopoli, 1786 M reg, B, W irr Biondi & Pietrelli, 1999;Battisti, 2006b;Causarano et al, 2006;Lorenzetti & Taffon, 2007;Fortunati & Battisti, 2008;Biondi & Pietrelli, 2009;Sozio & Battisti, 2009;Battisti et al, , 2012aBattisti, 2014b;Fraticelli, 2014;Battisti et al, 2015aBattisti et al, , 2016aBattisti et al, , 2018aBattisti et al, , 2020b Charadrius alexandrinus Linnaeus, 1758 M reg, W, B irr EN Lorenzetti & Taffon, 2007;Biondi & Pietrelli, 2009;Battisti et al, , 2012aPietrelli & Biondi, 2012;Battisti, 2014b;Biondi et al, 2014;Battisti et al, 2015a;Biondi et al, 2016;Pietrelli et al, 2016;…”