Institutionen för naturgeografi

Status, trends and values of wintering and migrating birds in Gialova Lagoon, Messenia, Greece

Viggo Norrby

Examensarbete avancerad nivå Miljö- och hälsoskydd, 30 hp 2017 2

Förord

Denna uppsats utgör Viggo Norrbys examensarbete i Miljö- och hälsoskydd på avancerad nivå vid Institutionen för naturgeografi, Stockholms universitet. Examensarbetet omfattar 30 högskolepoäng (ca 20 veckors heltidsstudier).

Handledare har varit Håkan Berg och Giorgos Maneas, Institutionen för naturgeografi, Stockholms universitet. Examinator för examensarbetet har varit Salim Belyazid, Institutionen för naturgeografi, Stockholms universitet.

Författaren är ensam ansvarig för uppsatsens innehåll.

Stockholm, den 28 juni 2017

Steffen Holzkämper Studierektor

Abstract

Areas of wetland have for the last century declined globally, mostly as a cause of anthropogenic activitities. Since many bird species are depending on wetlands, this have affected their populations negatively, and today many of the remaining wetlands are protected. This study has investigated the status and trends of Gialova lagoon in Greece, both as a stopover for spring migrating birds and as a wetland for wintering waterbirds. This has been done by doing an own field inventory for two weeks in March, and by compiling and analysing data from winter censuses from the last thirty years. Results showed that Gialova supported many migrating birds during the inventory, and several of these are threatened in Europe. The eastern parts of the lagoon are the most important and sensitive areas, due to the suitable habitat for foraging and protection. The analysis of winter data showed that only one species was increasing, while the rest and the total amount of waterbirds were stable or decreased. The number of birds during winter did not reach thresholds for qualifying as a Ramsar-site of international importance. However, the wetland’s geographical location and context makes it a important area to protect for migrating birds, and it also has values for the local community in terms of different ecosystem services.

Key words: Wetlands, waterbirds, bird migration, Greece, inventory, monitoring.

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Contents Abstract ...... 3 1. Introduction ...... 7 1.1 Purpose and study questions ...... 8 2. Method ...... 9 2.1 Study area ...... 9 2.2 Previous research in the study area ...... 10 2.3 Evaluation of Gialova as a bird habitat ...... 11 2.4 Spring migration inventory ...... 12 2.5 Compilation and analysis of midwinter counting data...... 15 3. Results ...... 16 3.1 Inventories in March ...... 16 3.1.1 Number of species and individuals observed ...... 16 3.1.2 Species of higher conservation values ...... 18 3.1.3 Birds spatial distribution within Gialova lagoon ...... 20 3.2 Midwinter counting data 1986-2015 ...... 21 3.2.1 Long-term trend analysis of most common species...... 24 3.2.2 1% of flyway population ...... 25 4. Discussion ...... 26 4.1 Spring migration ...... 26 4.2 Wintering waterbirds 1986-2015 ...... 28 4.3 Gialova’s values as a bird habitat ...... 29 5. Conclusions ...... 30 Acknowledgement ...... 31 References ...... 32 Appendix I: Swedish translation of some of the most mentioned species in the thesis ...... 35 Appendix II: Species list from inventory, March 2017 ...... 36

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1. Introduction In history, wetlands have been perceived as areas without greater values to offer the human society. Wetlands contribute to the spread of diseases like malaria, and the area that the wetland occupies could be used for something more valuable. This view of the wetland as something less valuable is the main reason why they for the last century have been disappearing at a high rate. Globally it is appreciated that since year 1900 64-71 % of all wetlands have disappeared (Davidson 2014). The rate and degree in which wetlands have vanished differs over the world, but Europe is a part where this negative trend is stated to have been one of the more significant (Zedler & Kercher 2005). During the 20th century two thirds of all European wetlands vanished, with a higher speed during the second half (Silva et al. 2007). The reasons for drying out wetlands in this region have to a large extent been for agricultural activities. Expanding fields for sowing and grazing, freshwater withdrawal for irrigation and new woodland creation are some of the major reasons why wetlands even today are declining in Europe, as well as in other parts of the world (ibid.). Much of the ones remaining are to a large extent also degraded by various, mostly anthropogenic, reasons such as eutrophication, salinization, pollution and by climate change (Zedler & Kercher 2005). The process of decreasing and degraded wetlands has caused large negative impacts on organisms dependent on this sort of environment. To this group of organisms birds is one of the major, where the subgroup waterbirds is the most apparent. Waterbirds are defined as “species of bird that are ecologically dependent on wetlands” (Ramsar convention 1994, art 1.2) including all waterfowl, seabirds and waders. For waterbirds wetlands are possibly the most crucial habitat, for breeding and not the least for migration. Migrating birds are dependent on wetlands both as wintering areas to stay in for longer periods but also as important “stopovers”. Stopovers, or staging sites, are areas which migrating birds make briefer stops at when they are migrating to or from their breeding grounds (Warnock 2010). They use these areas for resting and for foraging to refuel their fat reserves (ibid). Different birds have different migration routes which are more or less predetermined and evolved to pass by suitable stopover areas (Moore et al. 2005). When wetlands along a birds predetermined migration route disappear, the likeliness of the bird to complete its migration is strongly decreased (ibid.). The loss of wetlands has been stated to be one of the major reasons why populations of several waterbird species have shown a decline for the last century and into our days (Bortels et al. 2011, Morrison et al. 2001) The protection and conservation of wetlands and species connected to wetlands are today under a number of conventions and regulations. In the EU the most important regulation is the Bird- and habitat directive, where all member countries have agreed to protect habitats supporting birds listed in the Annex I (European commission 2016), forming the Natura 2000-network of protected areas. Wetlands and waterbirds are here central as habitats and species to protect. Wetlands in Europe are also protected under international conventions such as the Ramsar convention covering the large and most important wetlands (Ramsar convention 1994), and the by UNEP Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) with a focus on multilateral protection of migrating waterbirds and wetlands (AEWA 2017). This study aims to gather and analyse data of birds in a coastal wetland in Greece. The wetland is situated in an important migration route along the west coast of Greece (Birdlife International 2016). In this region there has been seen a massive decline in wetlands in the 20th century. Between 1950 and 1985 63% of all Greek wetland area

7 was lost (Silva et al. 2007), and a substantial part of these were within this migration route (Bortels et al. 2011). Today a larger part of the remaining wetlands is protected, but many are also heavily degraded by human activities (Maragou & Mantziou 2000). They are still threatened by drying processes coming from increased irrigation causing reduced freshwater inflow, or from draining and infilling intending to expand cultivated fields (Gerakis & Kalbutji 1998). In coastal areas, wetlands are meeting threats coming from increased tourism activity and construction works (Maragou & Mantziou 2000). Studies of Greek wetlands have shown that also wetlands with high protection status continues to see negative environmental changes (Kalivas et al. 2003), and even though they are legally protected there is no guarantee they get the needed protection and management (Apostolopoulou & Pantis 2009, Bazigou 2007). In the northern part of the west coast of Greece the most important wetlands exist in form of large lagoon and delta complexes. These wetlands attract high numbers of wintering and staging birds during migration (Liordos et al. 2014, Maragou & Mantziou 2000). In the southwestern part of Greece the wetlands are more scarce. Here, in the south westernmost region Messenia lies the Gialova lagoon, the wetland which status and trends as a bird habitat this essay aims to cover. Gialova lagoon is a wetland known for the number of birds using it all year round. On the internet the lagoon is widely described as one of the most important wetlands for migrating birds. There are however no recent publications of bird data or evaluations of Gialova’s status as a bird habitat, neither as a wintering area nor as a stopover for spring migrating birds. This study aims to fill in this gap of information and to analyse the gathered bird data.

1.1 Purpose and study questions Studying Gialova from a bird habitat perspective is interesting of various reasons. It is a wetland in a region where wetlands to a large extent have dried out or are degraded. This in combination with its location within a major migration route makes it a wetland with high conservation values, and the need for analysing old data and gathering new data with adequate methods is high. In this essay, the main purposes are to (1) analyse the wetland’s status as a spring migration stopover area by making an own inventory for two weeks in March. Focus will be on waterbirds and bird species with higher protection status. By doing this, the purpose is also to (2) map which part of the lagoon that holds the highest number of waterbirds and species with higher protection status. This information will be valuable when forming a management plan, something which the area is missing today (European union 2016). Lastly, the third purpose is to (3) evaluate the wetland as a wintering area for waterbirds by compiling and analysing winter counting data for the last 30 years, and from this see if any long-term population trends are visible. Since this thesis is a collaboration with Navarino Environmental Observatory (www.navarinoneo.gr), the hope is that this study will be of value for the observatory’s future research in the area. Another hope is that a complete inventory of the spring migration may be performed in the near future with similar methods. When studying the status and trends of birds in a wetland, purposes outside the topic of birds and migration might also be served. Firstly, it will contribute to the gathered knowledge about the situation of wetlands in a heavily affected region. Birds are often used as indicators of the conditions in our environment (Heath & Rayment 2001, Temple & Wiens 1989). For example, data from bird monitoring is useful when analyzing global environmental issues, such as the climate change effect on migration 8 and habitats (Bellisario et al. 2014), or as indicators of biodiversity (Heath & Rayment 2001). Secondly, Gialova is interesting since it is a protected wetland in a region where tourism is expanding, a process often threatening coastal wetlands in Greece (Maragou & Mantziou 2000). Could the conservation of a wetland like Gialova have other direct values for, and be supported by, the local community, easing the pressure coming from tourism? In the end, a successful conservation management goes through the local communities understanding and appreciation of the protected site. These questions will also be part of the final discussion, in relation to the bird data which is the core of the essay.

2. Method

2.1 Study area Gialova Lagoon, or Divari pilou lagoon, (36° 58' N, 21° 40' E) is a wetland located in the southwestern most part of Greece, in the region Messenia on the Peloponnese peninsula. The wetland is a coastal lagoon, a nature type defined as “areas of relatively shallow water that have been partly or wholly sealed off from the sea by the formation of depositional barriers, usually of sand or shingle, built up above high-tide level by wave action” (Bird 1994, p. 9). Gialova is both one of the few and one of the larger wetlands on the southwestern part of the Greek peninsula Peloponnese, but it is still with its 2.5 km2 much smaller than the Ramsar-sites in northern Greece. Nevertheless, it has a big variety of habitats and nature types. The largest part of the wetland consists of the main lagoon with a maximum depth of one to one point five meters. It has only one saltwater inlet through a small channel from the Navarino bay. To the south, the main lagoon is surrounded by a strip of marshes, meadows, cultivated fields, a car road and a beach towards the Navarino bay. In southwest, the lagoon is delimited by a rocky coastal area and a cliff at which top ruins of Navarino castle lies, which is giving the area cultural values. The area attracting most tourists is however the well-known Voidokilia beach northeast of the lagoon. The area between the beach and the lagoon is made out of sand- dunes. The northern part of the lagoon is made out of salt marshes and salt pond-like areas. North of this the area is dominated by cultivated field, mostly olive trees, some just adjacent to the wetland, but also areas of meadows, marshes and grazing ground. The eastern part of the lagoon has a very different habitat compared to the main lagoon. Fresh water inlets from the Xerolagodos and Tyflomitis river in the north respectively east make this area having a lower salinity and a habitat for reed beds and marshes with not as much open water. To the east, more meadows and agricultural areas are dominating, mostly olives, citrus trees and grazing ground. The difference between the eastern and western area is enforced by a dirt road going right across the lagoon, with the two different environments on each side of the road. Watching the satellite photo (Fig 1 and 2), the traces of human intervention is clear. Ditches, channels and sandbanks are traces from the manipulation of freshwater inlets, beginning in the 1950’s and 60’s with the purpose of making more land available for agriculture. During this process the lagoon lost one third of its size, with the purpose of giving more space for agriculture (Söderblom-Tay 2014). This was followed by more human intervention in both fresh- and saltwater inflow in the 1970’ and 80’s (Koutsobas et al. 2000). In 1993, a large oil spill in Navarino bay caused a large fish death in the lagoon (Dounas et al. 1998). In 1998 actions were made to lead the rivers back to the 9 lagoon to increase the freshwater inflow. In spring the salinity is the lowest because of a higher freshwater inflow, but the salinity increases during summer and autumn. The size of the wetland is also larger in spring and smallest in summer and autumn. The lagoon is used for aquaculture of some commercially popular fishes, such as mullet and sea bream (Koutsobas et al. 2000). Today one group of fishermen regularly fishes in the area. The whole wetland and nearest surroundings is identified by Birdlife International as an Important Bird Area (IBA) (600 hectare). The major threats to the IBA in the 1990’s were according to the Hellenic ornithological society (HOS) fishing, intensified agriculture causing increased salinity in the freshwater marsh, infilling and hunting. Threats of lower priority were tourism/recreation and agricultural extension (HOS 2016a). A more recent study, a bachelor thesis from 2014, showed that the major threats at that time were related to agriculture and possibly tourism expansion, while hunting no longer posed a major threat (Söderblom-Tay 2014). The freshwater inflow was better but still a major issue for the lagoon as a bird habitat (ibid). The wetland is also protected as a Natura 2000-area, qualified as Special Protection Area and a Special Area of Conservation (1010 ha). The area lacks a management plan, even though it has been attempts in forming one. Finally, the lagoon is also protected as a wildlife reserve. Altogether, the lagoon is officially well-protected and of national priority. It is not qualified as Ramsar-site, like ten other wetlands in northern Greece.

Figure 1. Satellite photo showing the lagoon within red border, and the surrounding areas outside; the Navarino bay in south and the Ionean sea in west. Red dot in map in upper right corner show Gialova lagoon’s position in the Mediterranean region.

2.2 Previous research in the study area Since Gialova is known as a good site for birdwatching, some monitoring of its birds has been done in the past. The longest series of data is coming from the International Waterbird Census (IWC), started by the Wetlands international in the 1970’s (Delany 10

2010). In this monitoring, all waterbirds are once per year counted during a midwinter day with the purpose of monitoring waterbirds’ winter populations. In Gialova, this has been regularly done since 1986, creating a series of data for the last thirty years. Gialova is since October 2016 counted once every month by a professional birdwatcher from the Hellenic ornithological society. The monitoring is supposed to continue to form a good basis of understanding how this wetland is used by birds during different times of the year. This data can support decisions of how to give the area proper management measures and to make it attractive for birdwatching. In 2010, more frequent inventories were made during summer and autumn, similar to the one this study has done, however the result was never published (Crespo Roncero 2010 (unpublished)). Birds spatial distribution was mapped, their breeding success was evaluated and the autumn migration was analysed. No such frequent counting has been performed for the spring migration in recent years. In 1996 data from spring of that year was included when assessing the area as an IBA (HOS, 2016a). An intention in this study is to try to repeat the methodology used in 2010 and in the monthly censuses, with the purpose of making this data comparable.

2.3 Evaluation of Gialova as a bird habitat Several studies use data from bird monitorings to evaluate wetlands as bird habitats and their need for protection. Methods coming from similar studies will work as the methods to evaluate Gialova lagoon, with some difference where it is regarded as needed, due to study design and site-specific conditions. Methods of other studies used in this study is described below, while their findings are further discussed in relation to this study in Discussion. Simply put, evaluations of wetlands as bird habitats can be done either by compiling and analysing old gathered data, or for sites not as well-monitored, by performing new inventories to get the data needed. When evaluating wetlands with bird data, it is common practice to use threshold values set by conventions and directives protecting wetlands (Bibby et al. 1998). One of these is the Ramsar convention created in 1971 which aims to identify and protect wetlands of international importance (Ramsar 2014). For a wetland to qualify as a Ramsar-site certain threshold values must be reached. The two Ramsar-criterias covering birds is the 1%-threshold, which means that if more than 1% of a waterbirds flyway-population (Wetlands international 2012) appears in a wetland, or if the wetland regularly supports more than 20 000 waterbirds, it may qualify as internationally important (Ramsar convention 1994). To qualify as an IBA or Natura 2000-area there are other thresholds and qualifications used, but for this study only the two Ramsar thresholds are used. These two threshold values will be used when analysing data from the midwinter censuses (IWC) in Gialova. Data from IWC can be used when evaluating wetlands and to see if they may qualify as a Ramsar-site, Natura 2000-area, IBA etc. The yearly censuses, started in 1970, now have created long series of data for many sites, which gives valuable information about long-term trends of waterbirds (Delany 2010). By looking at several species’ trends over the latest 30 years, it will also create an understanding in which direction Gialova is going as a habitat for birds. When using this data for population trends in Gialova, the trends will be compared to population trends at a larger geographical scale, using data from Wetlands international (2016) and IUCN Red List of threatened species (IUCN red list 2017). This may give insights if trends are depending on site-specific conditions or on conditions at a larger geographical level. This part of the study has more methodological similarities 11 to the study made by Liordos et al. (2014), covering the coastal lagoon Messolonghi in northern Greece. That study was said to be the first long-term trend analysis of winter data for a large Greek wetland. This study can then be said to be the first long-term trend analysis of winter data for a small to medium sized Greek wetland. Since the Ramsar criterias are mostly used for the most important and often larger wetlands, this study will also use focal species as indicators of the wetland’s status and importance of today. By doing this, it might give more information for a wetland of Gialova’s capacity. This method will be used for the spring migration inventory part of the study. Focal species in this study are waterbirds and bird species with higher conservation values. Waterbirds are chosen to be of focus since they are the most logic group to study when evaluating a wetland’s importance as a bird habitat. They are the group of birds characterizing a wetland and they are also heavily dependent on wetlands existence to maintain a stable population. The other group of focal species are birds appearing in the EU’s Bird Directive Appendix I (European commission 2016) or in the by IUCN made red list of threatened species in Europe (Birdlife international 2015). The first is a list of species used by the European Union to help decide if areas should be protected as Natura 2000-areas. The latter is a list used by the NGO Birdlife International when deciding which areas that qualifies as IBA’s. In the red list, species are divided in different categories, depending on the status of that species’ population. Searching for species in these lists and mapping their distribution can be methods used when studying possibly important bird habitats (Bibby et al. 1998, Blank 2010). This method implicates that the more threatened species, both in abundance and number of species, the higher is the conservation value of that specific site. In both these lists there are representatives from most groups of birds, including several waterbird species. Both methods above are only focusing on the conditions at the specific site, not considering its geographical context. When studying such a mobile organism as a bird, or especially migrating birds, it could seem rather strange to evaluate a wetland without considering the surroundings. This relates to studies highlighting the importance of wetland connectivity and plurality (Bortels et al. 2011, Moore et al. 2005, Smith & Chow- Fraser 2010). These studies mean that wetlands must be in such a high number and spatially distributed in such a way that birds have the possibility to regularly stop for resting during migration. The most challenging distances for a migrating bird are the ones where no good resting grounds are available (Moore et al. 2005), e.g. deserts and seas. But as wetlands continues to decrease, more and longer distances along the migration routes lacks suitable resting and feeding habitats. Therefore, it is interesting when evaluating smaller wetland’s importance for migrating birds to also put the wetland in its wider geographical context, to see what role the wetland has in the terms of wetland connectivity.

2.4 Spring migration inventory An own inventory of birds in Gialova lagoon during spring has been performed for this study. The inventory took place during two weeks in March, from the 9th to the 24th of March, with a total of seven inventory occasions at the lagoon. All inventories were made at almost the same time of the day, from 7 or 8 am to around 12 pm, following the same route, and all inventories were performed when weather conditions were good for bird counting, i.e. no heavy rain or strong winds. The aim was to make censuses every second day, but weather conditions and practical issues made some of the inventories to 12 be performed every third day instead. Also, one visit for preparation were made before the formal inventories to get familiar with area and how to best design the coming inventories. Two other visits were made at other times of the day to see if the birds’ distribution and species assembly were significantly different from the formal censuses. At these extra visits the birds were not counted and are not part of the result. The inventory was made by bike, and the birding equipment was a binocular (8x magnification) and a scope (28x). Also, a tally counting device was used to make the counting easier for birds appearing in larger numbers. The field guide Collins birds guide (Svensson et al. 2010) were used when help in bird identification was needed. Number of birds and location of birds were noted in field, and later transferred to Microsoft Excel.

Date: Weather:

9/3 Light rain, no wind. 10-14 °C

12/3 Clear. No wind -> brief wind. 11-17 °C

14/3 Clear. No wind -> brief wind. 9-15 °C

17/3 Clear. No wind -> moderate wind. 10-16 °C

20/3 Clear. No wind. 14-20 °C

22/3 Cloudy. No wind -> moderate wind. 13-17 °C

24/3 Clear. No wind. 14-21 °C.

Table 1. Dates of inventories and weather conditions.

The methodology used for inventory has many similarities with, what the Swedish EPA calls “Rastfågelräkning”, meaning counting of staging and feeding birds, since it is a suitable method when counting birds at sites where bigger number of birds are concentrated during migration (Blank 2010). The method is often used when collecting the highest number of certain species during chosen periods of the year, e.g. during peak of migration. While “Rastfågelräkning” uses the counting method point counts with predetermined observation points, this study used a combination of this with a line transect. In the latter, censuses are made simultaneously as going (or biking) along a predetermined route/line transect. By doing this combination it is possible to make stops at predetermined observation points with good views, but also note and count the birds between the observation points. This will make a higher proportion of the birds in the area to be part of the data. In this method, all observed birds (seen and heard) are counted, i.e. a complete census (Gregory et al. 2004). Focal species were noted and counted in exact numbers, while other species were noted and their numbers only estimated. The focal species were part of the mapping of

13 their spatial distribution within the lagoon (see Fig. 2). Zones of the lagoon have been determined by Navarino Environmental Observatory and HOS, and used in earlier monitorings. In this study, some of the zones are not counted by various reasons. The zones neglected are those with only agricultural habitats, in which waterbirds are not primarily occurring. A reason for neglecting these areas were also that if they were to be monitored as well, it would have been difficult to count all areas the same morning and the risk for double counting would be higher. Left is fifteen zones in which the focal species have been counted and mapped (Fig. 2). Moreover, in this study the fifteen zones were combined to five different zones when presenting the result. This is made partly to make it easier for the reader to get an overview of the birds’ spatial distribution, and also to combine different zones with similar habitats. L is the open water area, the main lagoon with a high salinity, P+R are the salt ponds and salt marshes. A+B+C+D+E+F+G are all the areas with lower salinity and more freshwater with areas of open water, reed and wet meadows. S+T+O are drier meadows, grass and agricultural areas adjacent to the lagoon and some channels. H is an area dominated by mud and fen separated from the lagoon by a ditch.

Figure 2. Map showing the study area. Marked on the map are the biking road from which the inventory was made, the observation points and the counting zones.

It is important to be aware that the result is not a complete inventory of the spring migration, but for a two-week period during migration. However, this inventory will 14 capture some species’ peak of migration and parts of several others, which makes it possible to get a good understanding of the site’s status in spring. Nevertheless, an inventory of the complete spring migration would of course be valuable, and the hope is that this study and its methodology can be repeated in coming inventories. It is difficult to avoid that this methodology is putting some higher demands on the person making the counting. The person, or persons, must be familiar with all the relevant bird species’ different plumages, behaviour, habitat associations and not the least their sounds since many birds only will be heard. Also it is crucial not to make double counts of the birds in the area. This is, according to Blank (2010) and Bibby et al. (1998) something that the counter must consider at all censuses. In this study, double censuses could be avoided by counting from observation points covering different areas and by being aware of the movements of the birds in the lagoon, and also by completing each count in one morning. Even though the method is called a “total” counting, it is not completely total since it is very difficult to observe all birds in a wetland. Some birds will always be hiding in high grass or reeds and stay quiet during censuses. By making several visits, a larger part of the species will be observed at some time, but the census can never be fully complete in terms of numbers, which then might have consequences for the validity of evaluation of a wetland. Since Gialova is a wetland smaller than many of those in similar studies, an inventory of this kind will probably have a higher accuracy than in the larger wetland complexes (Gregory et al. 2004).

2.5 Compilation and analysis of midwinter counting data In the part of the study analysing data from the IWC, the emphasis is put on finding and analysing trends of waterbird species, much similar to the studies of Messolonghi (Liordos et al. 2014) and to some extent the one of Cota Doñana in Spain (Rendón 2010) and the southern coast of Sweden (Nilsson 2014). Numbers of birds will be compared to those threshold values used for Ramsar-sites, which is a method sometimes used by other studies e.g. Liordos et al (2014). Winter counting data for Gialova exists for 26 years out of a timespan of 30 years, from 1986 to 2015. Censuses were not made in 1987, 1988, 1991 and 1999, therefore data from those years are missing. Birds being part of the long-term trend analyses will be the most abundant species throughout the years. The reason for this is that those species are more likely to show real and clear trends as a result of specific changes at local or regional level, while many other species occurring in lower numbers and few years are more likely to have an appearance based on other random conditions. Still, the trends should be read mostly as estimates since most of the species included are appearing in smaller numbers, compared to numbers in similar studies. Unlike Liordos et al. (2014) which excluded all species that didn’t occur every year, this study is not that strict because species with quick changes in occurrence would then be excluded, even though these might be the most interesting cases. The trend analysis’ are made for the whole time period, but also separately for the last ten years. By doing this it is hopefully easier to see if trends are the same through all years or are changing in more recent time. The trends of species in Gialova are compared to their trends at a flyway population level, using data from Wetlands international (Wetlands international, 2012). The flyway population trends are not for the exact same time period for all species, but all are for at least a five-year period and after year 2000. The compilation of data, visualization of data and eventual trend analysis were made in Microsoft Office Excel.

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The winter data is gathered by different persons throughout the years and therefore there is a risk of some errors in the data. Those errors might come from different level of experience with the person/persons making the census or other differences in conditions between the years, making the census not completely comparable. However, the IWC is designed in such a way that comparisons should be possible, and the counters always have the same directives to follow when doing the census. Liordos et al. (2014) also mention that the numbers from the IWC do not have to be showing the peak of numbers during winter since the peak might arrive at different times of winter for different species and also be varying with yearly weather conditions. In the case of Messolonghi and Doñana, the risk is higher of species being at too long distance or being missed, than for Gialova where the birds are at an easier overviewed area.

3. Results

3.1 Inventories in March

3.1.1 Number of species and individuals observed A total of 120 bird species were observed during the seven days of monitoring. Number of species per day were ranging between 79 and 94, with a weak tendency of more species being observed as migration proceeded. At the same time, the total number of birds per day were decreasing as migration started and the wintering species left the area, such as the Greater flamingo and Common coot. The number of species and total number of birds also seemed to vary depending on weather conditions. For example were both number of species and individuals (Fig. 3 & 4) lower the warmest and sunniest days (see Tab. 1). Compared to inventories made in summer and autumn 2010, the result indicates that Gialova is richer in species during spring migration than autumn migration. In May-October 2010, 103 species were observed in total and 41 species during one day at the most (Crespo Roncero 2010 (unpublished)). To put the number of species in a context, 271 species have been observed in Gialova through all times (ibid). The number of breeding species is lower, probably between 50 and 100, since this is an area mostly used by migrating birds.

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Species per day 120 120

100 94 92 85 87 79 80 83 80

60

Nrspecies of 40

20

0 9/3 12/3 14/3 17/3 20/3 22/3 24/3 All days Date

Figure 3. Graph showing number of species observed per day during inventory.

Total number of birds per day (Average per day: 2105) 3000 2524 2280 2272 2294 2500 2155

2000 1650 1560 1500

Nrbirds of 1000

500

0 9/3 12/3 14/3 17/3 20/3 22/3 24/3 Date

Figure 4. Graph showing number of birds observed per day during inventories.

During the two-week long monitoring, Common coot (Fulica atra) was the bird with the highest daily sum (449), followed by Teal (Anas crecca) and Barn swallow (Hirundo rustica) (378 respectively 350). Some species, such as Barn swallow had high numbers only in one or two days, while Teal had higher numbers all days. For waterbirds, ducks and their allies (e.g. coot and grebes) made out the largest group, with herons and flamingos at second place. Waders and gulls were found in relatively small numbers. (See complete list in Appendix II).

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Species with the highest daily number 500 450 400 350 300 250 200 Nrbirds of 150 100 50 0

Figure 5. Diagram showing the 15 species with highest daily sum during the inventory 9-24 march.

During the inventory, the migration of birds going north started. It was clear that Gialova is a wetland used as a stopover for many long-distance migrating birds. Several species wintering south of Sahara arrived for the first time of the year during the two-week period, such as Black-winged stilt (Himanotopus himanotopus), Ruff (Philomachus pugnax), Marsh sandpiper (Tringa stagnatilis) and Great reed warbler (Acrocephalus arundinaceus). Other species, such as the Greater Flamingo (Phoenicopterus roseus), leaved Gialova after staying here during the winter months (see fig. 6).

Black-winged stilt Greater flamingo 60 300 40 200

20 100 winged winged stilts - 0 0

9/3 12/3 14/3 17/3 20/3 22/3 24/3 9/3 12/3 14/3 17/3 20/3 22/3 24/3

Greater Greater flamingos Black Date Date

Figure 6. A site for migration. Two graph showing two species with different migration pattern; the Greater flamingo (P. roseus) which mostly spend the winter here and thereafter leaves the area, and the Black-winged stilt (H. himantopus) which winters in Africa but breeds in Gialova (or further north) during summer and therefore increased in numbers during inventory.

3.1.2 Species of higher conservation values 27 species listed in the EU’s Bird directive, Annex I were observed during the seven days of inventory. Outside the ordinary seven inventories, another two species listed in the Bird directive, Annex I were observed, Mediterranean gull and Spur-winged lapwing. The latter is a rare vagrant in Europe and only breeds in Turkey, with exception of a few pairs in northeastern Greece and Cyprus.

Species Highest Days observed 18

daily sum (out of seven) Spoonbill 2 3 Glossy ibis 11 1 Crane 4 6 Greater flamingo 194 7 Purple heron 4 2 Squacco heron 1 2 Great white egret 28 7 Little egret 32 7 Bittern 1 1 White-eyed pochard 4 3 Hen harrier 1 2 5 Marsh harrier 10 7 Osprey 1 5 Peregrine falcon 2 2 Black-winged stilt 41 5 Spur-winged lapwing* 1 1 1 Ruff 1 85 7 Golden plover 9 3 Wood sandpiper 9 4 Kentish plover 41 7 Slender-billed gull 2 4 Mediterranean gull* 2 1 Caspian tern 1 9 1 Kentish tern 10 7 Kingfisher 1 22 7 Short-toed lark 2 1 Sand martin 4 1 Tawny pipit 3 4 Mustached warbler 1 4 Table 2. Observed species listed in Bird directive, Annex I (European Commission 2016). Mid column shows highest daily sum of each species during field inventory, March 2017. Right column shows number of days species were observed. *observed outside the ordinary monitoring. 1 also listed in EC red list. 16 species listed in the IUCN Red List for Europe were observed in Gialova during the inventories (IUCN red list 2017). Europe/EU27 Highest Days observed Species status daily sum (out of seven) Curlew VU/VU 21 6 Saker falcon VU/VU 1 1 Meadow pipit NT/VU 80 7 Common coot NT/LC 449 7 Marsh sandpiper LC/EN 11 2 Garganey LC/VU 70 7 Wigeon LC/VU 247 7 Pochard VU/VU 9 3 19

Pintail LC/VU 80 7 Redshank LC/VU 35 7 Black tailed godwit VU/EN 8 2 Caspian tern LC/NT 9 1 Ruff LC/EN 85 7 Spur-winged lapwing LC/VU 1 1 Hen harrier NT/LC 2 5 Kingfisher VU/VU 22 7 Table 3. Observed species listed in red list for Europe/EU27. Second column shows classification of status in red list: VU=vulnerable, NT= near threatened, EN= endangered, LC=least concern. Third column shows highest daily sum of each specie during field inventory. Forth column shows number of days species were observed.

3.1.3 Birds spatial distribution within Gialova lagoon Focal species were counted in the same, but not all, zonal areas as the earlier censuses performed by Navarino Environmental Observatory and Hellenic Ornithological Society (See Fig. 2 in section Method).

Focal species spatial distribution (individuals, all days) (n= 10539) H T+O+S 5% 1%

A+B+C+D+E+F+G 31% L 50%

P+R 13% L P+R A+B+C+D+E+F+G H T+O+S

Figure 7. Graph showing which zones focal species were located in. The main lagoon, zone L, was the area holding the highest number of birds of focal species. This is the area in which the most abundant species occurred in, such as Greater flamingo (P. roseus) and Great cormorant (P. carbo). Also the northeastern part of L, which is partly closed by the sand banks, were popular for congregations of dabbling ducks and Coots. The freshwater and reed areas, A-G, were clearly favored by most of the dabbling ducks and herons. The wet meadows in these areas were used by a variety of birds; larger waders, dabbling ducks, Water rails (Rallus aquaticus) and Meadow pipits (Anthus pratensis), while the open waters and channels held Little grebe (Tachybaptus ruficollis), diving ducks and Kingfishers (Alcedo Atthis). The ponds in P+R+S were the areas holding the majority of small waders such as Kentish plover (Charadrius alexandrines), Dunlin (Calidris alpina), Little stint (Calidris minuta) and Ruff (P. pugnax). H were preferred by waders adapted to less salty water and more marsh- like habitat such as Little ringed plover (Charadrius dubius), Marsh sandpiper (T. 20 stagnatilis) and Temminck’s stint (Calidris temmincki). The zones holding least number of the focal species were the agricultural/grassy areas adjacent to the wetland. Nevertheless, these areas were preferred by some species with conservation values such as Little egret (Egretta garzetta), Curlew (Numenius arquata), Tawny pipit (Anthus campestris) and Meadow pipit (A. pratensis). Also a family of three Cranes (Grus grus), which is less common in southern Greece, were seen in zone O most of the days.

Figure 8. Map showing what parts of the wetland focal species mostly occurred in during the inventory. Letters A-H are the zones in which bird were counted.

3.2 Midwinter counting data 1986-2015 Winter counting data exists from 26 years out of a timespan of 30 years, from 1986 to 2015. Censuses were not made in 1987, 1988, 1991 and 1999, therefore data from those years are missing. Censuses are standardized and are always performed during one day in midwinter (see Method for more).

21

All waterbirds per year (7122, 1706-19325) 25000

20000

15000

10000

5000

0

1990 2012 1989 1992 1993 1994 1995 1996 1997 1998 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2013 2014 2015 1986 Figure 9. Graph showing total numbers of all waterbirds per year, counted in the yearly midwinter counting of Gialova. Below title in figure is average per year and range.

For the period 1986-2015 the average number of birds counted during IWC is 7122 per year, ranging from 1706 to 19325. The range in number between years is large but not completely unexcepted or unusual when it comes to midwinter censuses in wetlands. Big variations were also seen in the case of Messolonghi in Greece and Doñana in Spain (Liordos et al. 2014, Rendón 2010). The total numbers of all waterbirds have had a negative trend for the whole period of thirty years. For the last twenty years the decline has been weaker, with the exception of the dramatic fall from 18738 in 2002 to 5834 in 2003. For the five last years, numbers have been more stable but in lower numbers between 1706 and 2577 birds. Two periods are standing out with much higher numbers than the average, 1989- 1992 and 2000-2002. Not in any year the total number of waterbirds exceeded 20 000, which is the threshold value for Ramsar site qualification. Closest were in year 2000 with 19325.

15 most common species 1986-2015 80000 70000 60000 50000 40000 30000 20000 10000 Nrbirds of per species 0

Figure 10. Diagram showing the 15 most common species in numbers during the IWC 1986-2015.

22

Common coot (F. atra) is (by large numbers) the most common species reaching almost 70 000 counted during the winter censuses. Coot is followed by Teal (A. crecca) and Pochard (Aythya ferina).

Coot (F. atra) (2639, 84-8900) 10000 9000 8000 7000 6000 5000

F. ATRA ATRA F. 4000 3000 2000 1000

0

2000 2001 2002 1986 1989 1990 1992 1993 1994 1995 1996 1997 1998 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 YEAR

Figure 11. Graph showing numbers of common coot (F. atra) 1986-2015. Numbers below title are mean value and range. The graph for Coot has a very similar pattern to the one for all waterbirds (Fig. 10). A reason for this could be that the Coot makes out such a big part of all waterbirds. For the last ten years it has been around 500-2000 individuals, but has been as much as 9000 in 2002. This is around one third to one half of all waterbirds counted yearly.

Pochard (A. ferina) 4000 3500 3000 2500 2000

A. FERINA A. 1500 1000 500

0

1986 1989 1990 1992 1993 1994 1995 1996 1997 1998 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 YEAR

Figure 12. Graph showing numbers of Pochards (A. ferina) 1986-2015. Pochard (A. ferina) stands for the most negative trend in numbers for the whole time period. From regularly being counted in very high numbers in the beginning of the 23 period (up to 3500), Pochards have now not been seen at all at for the last seven midwinter censuses. This is also the only species which have gone from being seen most or all years in the beginning to being completely absent in the later period.

Greater flamingo (P. roseus) 600

500

400

300

P.ROSEUS 200

100

0

2010 1986 1989 1990 1992 1993 1994 1995 1996 1997 1998 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2011 2012 2013 2014 2015 YEAR

Figure 13. Graph showing numbers of Greater flamingo (P. roseus) 1986-2015. Greater flamingo (P. roseus) is one of few species with a positive trend. From the first one observed in 1996, the increase has been steady, with the exception of 2007 and 2010 when numbers were very low. For the last five years, numbers have been around 300-500 each winter. This positive trend has been seen in more wetlands and coastal areas around the Mediterranean Sea, which implies that the reason for the increase is not only at a site-specific level, but rather at a regional Mediterranean level.

3.2.1 Long-term trend analysis of most common species Species included in the long-term trend analysis are the 22 most frequent observed species during the midwinter censuses. Since waders and gulls were not mandatory to count during the first ten years, they only have complete numbers from 1996. Out of the analysed species, only the Greater flamingo is clearly increasing through both time periods. Three species are decreasing during all both periods, being Northern pintail (Anas acuta), Pochard (A. ferina) and Coot (F. atra). Among waders and gulls, trends were more difficult to see since the numbers are low and gulls are known to be very mobile. Nevertheless, none of the waders are increasing in any of the periods, and the same goes for Black-headed gull (Larus ridibundus), while Yellow-legged gull (Larus cachinnans) is the only one in this group increasing for the last ten years. Generally, more species have negative trends for the last ten years, compared to the trends of the complete thirty-year period, where only three species have negative trends (but in the longest time period, fewer species are included). Looking at the latest period, eight of the twenty-two species is shown to have the same trend in Gialova as in the flyway population, while twelve is contradictive and three is unclear. 24

Species (n= 22) 1986- 2006- Flyway 2015 2015 pop Wigeon → ↓ → Teal → ↓ ? Gadwall ↑ ↑ ↑ Mallard → ↓ ↓ Northern pintail ↓ ↓ ↓ Shoveler → ↓ → Pochard ↓ ↓ ↓ Little grebe → ↓ ↑ Great cormorant ↑ → ↑ Little egret → ↓ → Great white egret ↑ → ↑ Grey heron → ↓ ↑ Greater flamingo ↑ ↑ → Common coot ↓ ↓ ↑ Kentish plover ? ? Little stint ↓ ↑ Dunlin → → Northern lapwing ↓ ↓ Common snipe ? ↓ Redshank → ↓ Black-headed gull ↓ ↓ Yellow-legged gull ↑ ↑ All species ↑ 4 ↑ 3 ↑ 8 → 7 → 4 → 5 ↓ 3 ↓13 ↓ 7 ? 0 ? 2 ? 2 (n=14) (n=22) (n=22)

Table 4. Table showing the long-term trend of 22 species. The arrows indicate if the population of the species are decreasing, increasing or are staple. ?-mark means the trend is unclear. The column to the far right shows the flyway population trend, i.e. in a larger geographical scale, with data from Wetlands international (2012).

3.2.2 1% of flyway population No species reach the threshold value of 1% of its flyway population in Gialova for the midwinter censuses 1986-2015. Closest to reach the threshold were Greater flamingo (P. roseus) which in 2012 were counted in 516 individuals. The threshold for this species were 600, and with the increasing trend of the Greater flamingo in mind it is possible it could reach the 1%-threshold the coming years. On the other hand, the flyway population is also increasing, making the 1%-value larger. Other species were relatively far from reaching the threshold, some were in numbers close to half from the 1%, such as Wigeon (Anas Penelope) and Pochard (A. ferina). Pochard’s number were however a record from 1989, since then it has decreased dramatically, and also note that the 1% number from Wetlands international (2012) could be more recent than some of the species’ highest record.

Species 1% of flyway Highest number % of flyway population 1986-2015 population Wigeon 3000 1560 (2001) 0.5 Teal 10 200 2350 (2000) 0.2

25

Mallard 20 000 700 (2006) <0.1 Norhtern pintail 7500 1490 (2000) 0.2 Shoveler 4500 780 (2004) 0.2 Pochard 8000 3500 (1989) 0.4 Coot 25000 8900 (2002) 0.4 Great cormorant 4500 1000 (1996, 2000) 0.2 Little egret 560 210 (1998) 0.4 Great white egret 460 192 (2009) 0.4 Greater flamingo 600 516 (2012) 0.9 Kentish plover 400 62 (2011) 0.2 Table 5. Table showing the twelve most common species during IWC in Gialova. First column shows the 1% of species’ flyway population (Wetlands international 2012), and the second column shows the highest number in Gialova of that species during IWC 1986-2015. The third column shows the percentage of the flyway population from the number in the second column.

4. Discussion

4.1 Spring migration Results from the inventory of spring migration show that Gialova lagoon still is a wetland with important bird habitats, supporting several species with higher conservation values and larger numbers of waterbird species during spring migration. When comparing the result in this study to the one made in the summer and autumn of 2010 (Crespo Roncero 2010 (unpublished)), the site seems to be more important during spring. The reasons for this are not certain. Probably the result from Gialova is related to the differences in suitable habitat throughout the year. In spring the freshwater inflow is the highest, the salinity lower and the wetland area the largest, making it an area with more suitable habitats for resting and foraging. Many of the species seen in the inventory are relaying on freshwater, such as several ducks and herons (IUCN red list 2017), making Gialova in autumn a harsher environment. The seasonal variation might also depend on its location on the Balkan peninsula. When it is at the southwestern most part of the peninsula it will work as the first suitable stopover for many exhausted spring migrants who have flew non-stop over the Mediterranean Sea, or even non-stop from south of Sahara (Bortels et al. 2011). The situation in the autumn is very different. When migrating from north to south over the Balkan peninsula the birds have had the possibility of staying in the larger wetlands in the northern part of Greece, which are very suitable stopovers for waterbirds (HOS 2016b). This makes a stop at Gialova not as crucially important as it may be in spring. Gialova could, however, be important as the last possible stop before crossing the Mediterranean Sea, for those birds in need of more frequent stops. Even though, the location on the peninsula combined with better habitat during spring, should be the main reason why it holds more birds and species in spring. Result showed that Gialova is a wetland mostly used by ducks (including coots) and herons (including flamingos and cormorants). Waders, which in other coastal wetlands can be seen in high numbers were here in relatively low numbers. The reason should be that the largest habitat types are more suitable for ducks and herons i.e. the larger areas of open water, reed beds and high grass in meadows. Waders prefer very shallow water, mudflats and meadows with short grass, areas which in Gialova are

26 smaller (area P, H and some of the eastern parts). The mapping of focal species showed that all parts of the wetland supported waterbirds and threatened species. The eastern part supported most species, while the main lagoon held the largest numbers, mostly thanks to Greater flamingos and Greater cormorants which were strictly bound to this area. In terms of biodiversity and threatened species, the eastern part and the salt pond areas seemed to be the most important for migrating birds. This was expected since these areas showed a larger diversity of habitats, which also are scarce and ephemeral in this region of Greece and therefore should attract many birds. However, these habitats are also the most difficult to protect. Firstly, high evaporation and reduced freshwater inflow makes these areas dry in summer, a process expected to increase with climate change when prolonged droughts and warmer temperatures are getting more common (Giorgi & Lionello 2008). Secondly, these areas in the wetland’s fringe are the ones most threatened by agriculture and/or tourism expansion (Maragou & Mantziou 2000). This was apparent in the northern part with olive groves just adjacent to the lagoon, and the northwestern part where a parking lot for visitors to Voidokilia beach is just next to the by wader’s popular ponds. Worth noting when discussing the birds’ distribution is the fact that this inventory was made for two weeks in March, meaning that species arriving later in spring not could be covered. To this category of species are Collared pratincole (Glareola pratincola), Glossy ibis (Plegadis falcinellus) and Wood sandpiper (Tringa glareola) which all were part of the motivation why Gialova were classified as an IBA (HOS 2016a). Most of these species arriving later in spring are birds preferring freshwater, reeds and meadows (IUCN red list 2017), i.e. the same habitats that showed to be important for most species in this study. Among the observed threatened species, 23 out of 27 species in the Bird Directive Annex I are connected to wetland or water habitats (European Commission 2016). The reasons for having them on the list are in almost all cases due to habitat loss coming from loss of wetlands (ibid). The most common reasons for having them in the Annex I, are the intensification of agriculture and drainage of wetlands for agricultural activity, affecting their breeding and wintering habitats (ibid). Other reasons mentioned are for example the use of agrochemicals, disturbance from tourism activities and illegal hunting. Agricultural activities have been stated as one of the threats to Gialova as well (HOS, 2016a), especially the way agriculture may affect the freshwater inflow. With the result of this study showing that most of the species with conservation concerns have intensified agriculture as major threat, agriculture can be said to be of major concern for Gialova’s future as an important bird habitat. It is unclear how the use of agrochemicals in the region may affect Gialova’s avifauna. It could be an interesting focus for coming research in the area to investigate what chemicals that are used in the watershed of Gialova and what concentrations that reaches the lagoon. When forming a management plan for the area, the previous mentioned agricultural areas in east and north should be prioritized in terms of protection and management. The relation with farmers adjacent to the eastern and northern part will be important to form a sustainable way of agriculture, where both the threatened bird’s habitat and the livelihood of farmers can prosper. Furthermore, when doing the inventory, it was clear that Gialova is a suitable place for studying the birds’ phenology i.e. their seasonal variation in appearance. It was easy to establish when the first individual for the year of a certain species arrived. Other studies have stated that migrating birds now are arriving earlier in spring, presumably as an adaption to a warmer climate with earlier springs (Jonzén et al. 2006). These

27 patterns are difficult to capture in the monthly censuses compared to more frequent inventories, like in this study. Some species, like the first Garganey (Anas querquedula) and Ruff (P. pugnax), arrived between the two censuses of February and March and also showed their highest numbers in this in-between period. Frequent censuses would therefore be valuable to perform during the migrating period (Bibby et al. 1998), but unfortunately they are difficult and demanding to perform, compared to the monthly. The monthly counting is also valuable to keep going to have longer series of data for all months. Outside of this study’s focus, it can also be mentioned that during inventories large numbers of passerines were observed in the surrounding agricultural areas, especially around the olive growths. These areas held large numbers of Song trush (Turdus philomelos), Blackcaps (Sylvia atricapilla) and Chaffinches (Fringilla coelebs) and other passerines. An interesting focus of coming studies in this area could be to describe these species’ patterns of occurrence during migration in olive growths in this region, and how they might be affected by different farming techniques.

4.2 Wintering waterbirds 1986-2015 The analysis of data from the IWC shows that Gialova lagoon has the possibility of holding larger numbers of wintering waterbirds. However, no species reached the 1%- threshold, and the total number of waterbirds did not exceed 20 000. Also, the site has a long-term trend of decreasing numbers in almost all waterbird species. Greater flamingo (P. roseus) is the only species with a clear positive trend, while species such as Pochard (A. ferina) have gone from 3000 in the 1980’s to 0 the last winters. Several other ducks and Coot (F. atra) also have decreasing numbers. So, what do these, mostly negative, trends tell us about Gialova lagoon as a bird habitat? When comparing this study with Liordos et al.’s (2014) analyzing IWC-data 1982-2012 in the Messolonghi lagoon in northern Greek, there are signs that the trends in Gialova are dependent on site-specific reasons. In Messolonghi the total number of waterbirds increased over long time, and 20 out of the 28 most abundant species were increasing, and only two were decreasing (and two were unclear). They found that the trends among species in Messolonghi mostly correlated with the same species’ trends in other countries, while this was not to the same extent the case in Gialova. Nevertheless, it is possible to see some similarities between Messolonghi and Gialova as well, for example both sites have seen the same dramatic decrease of Pochards, and an increase of cormorants and herons. In the latter group, not all were increasing in Gialova, but some were and others were stable, contrasting to most other groups which were decreasing. Liordos et al. (2014) saw a tendency that fish-eating birds were increasing more than algae-eating birds. One possible explanation to trends of bird populations in Gialova could therefore be related to the fish population and the aquaculture, and/or the condition of algae in Gialova. The clear increase of Greater flamingo is something that has happened at a broader scale and not just in Gialova. Studies have shown that the Mediterranean population has seen a stable increase during the last decades (European commission, 2016), so it is not surprising that this is the case at Gialova as well since it is a very suitable habitat for the species. One of the more dramatic changes among species in Gialova, the disappearance of Pochard, does not neither have to be a response to conditions in the lagoon. Studies have shown that wintering areas of closely related species have moved further northeast for the last decades (Lehikoinen et al. 2013), away from southern Greece. Also, Pochard is one of the species which have had a negative trend in most parts of Europe for 28 decades (Wetlands international 2012). These two cases show how a wetland’s population can change for reasons outside the site’s condition. When comparing Gialova to Messolonghi it is important to be aware that the latter are many times bigger than Gialova and divided in different wetland complexes, and therefore have very different prerequisites of holding large and more stable populations. Unfortunately, no similar studies made for wetlands of Gialova’s size in a comparable region could be found to compare with. The species mentioned above had such clear trends and appeared in such large numbers that their trends were easy to see. Other species in Gialova were in relatively small numbers (compared to Liordos et al (2014), Rendón (2010) etc.), making eventual trends more difficult to discuss. This could be seen as a limitation when using this kind of methodology for a wetland of Gialova’s size. What can be said about the trend of the total number of waterbirds in Gialova is that it is similar to the pattern of other major wetlands of Greece. Maragou & Mantziou (2000) stated that the number of wintering waterbirds in Greece Ramsar sites were decreasing in all, except Messolonghi and one other. Studies of wintering populations of waterbirds have shown that the temperature is possibly the most important factor affecting the numbers from year to year (Adam et al. 2015). This might be one of the more likely explanations to the three winters the numbers in Gialova were much higher than the average. Adam et al. (2015) found that very cold winter in northern and central Europe forced the birds to migrate further south to find open water, making concentrations to appear further south than usual, in places such as Gialova. In the same way, a warmer winter makes it possible to avoid flying further south than necessary, lowering the numbers in southern wetlands, as certain years in Gialova. It might also be a major explanation to the general decrease in wintering waterbirds in Greek Ramsar sites (Maragou & Mantziou 2000). An interesting comparison can be made with Coots, between Gialova lagoon and Messolonghi lagoon. The years when Gialova had the highest numbers of Coots, 1989-1992 and 2000-2002, Messolonghi happened to have the lowest numbers of Coots in the period 1982-2012 (Liordos et al 2014). This could be an indication of some external factor causing Coots migrating further south some years, where temperature should be one possible factor. A similar, but not as clear, relation is also visible for the total number of waterbirds in Gialova and Messolonghi (ibid.). Further analysis, with more species and more wetlands, is needed to better understand the distribution of wintering waterbirds in Greece. The relationship of weather conditions (and specifically temperature) and European winter populations, makes this kind of monitoring data interesting when studying climate change effect on birds (Nilsson 2014, Adam et al. 2015). This strongly motivates why the censuses of Gialova has to continue. The unique location in southernmost Europe and the already are existing long series of data makes it possible to follow trends of several interesting species.

4.3 Gialova’s values as a bird habitat Gialova lagoon has in this study been shown to be a wetland with habitats supporting several threatened species during spring migration. In winter time it holds larger numbers of waterbirds, but the long-term trends are mostly decreasing numbers. There is no doubt that the result of this study’s spring inventory and winter data analysis, confirms previous descriptions of Gialova as an area with important habitats supporting many birds. However, it cannot be said to be of international importance in this sense, according to qualifications in the Ramsar-convention (Ramsar convention 1994). It is 29 interesting to briefly discuss this matter, in the light of this study. When searching similar studies for comparison, it was clear that it is not very common to perform a study like this for a wetland of Gialova’s relatively small to medium size. Rendón (2010), Liordos et al. (2014), Nilsson (2014) and other studies all covers wetland complexes many times bigger than Gialova. Of natural reasons, larger wetlands are more prioritized to make comprehensive studies of since they can hold larger populations and more species and therefore reach threshold values giving them higher conservation statuses. This is a problem for smaller wetlands; they are not perceived as valuable as the larger ones and are not very likely to reach the threshold values needed for getting the best protection (Smith & Chow-Fraser 2010). Taking Gialova as an example, it might not be large enough to reach Ramsar threshold values, but it has other values easily missed when only studying the numbers of waterbirds. Placing it in its larger regional context, it can be stated to be one of few IBA’s in southwestern Greece (HOS 2016b), also along an important migration route (Birdlife International 2016). If this wetland was to be heavily degraded or completely dried, there is no wetland replacing it as a first stopover closer than 110 km further north along this route (HOS 2016b), making this a very important node in the connectivity of wetlands (Smith & Chow-Fraser 2010). However, important habitats in Gialova are under threat, mostly from agriculture and expansion of tourism. A possible way forward to meet both the expanding tourism and the needed conservation of the wetland, could be to develop its ecotourism. The wetland has good accessibility, a road taking visitors around and into the lagoon, and the relatively small sized area makes it possible to see many habitats and a large diversity of birds at close distance, without too much effort. Since the surroundings of Gialova today are known as a tourist destination, especially the big relatively new hotel complex some kilometers north of the area, the ecotourism should be able to develop for the area, for example with birdwatching activities and education for school classes. Income from ecotourism could both be an income for the local community making them positive to conservation, and also for funding some of the conservation. However, as a site for international birdwatchers, the Ramsar-sites of northern Greece are probably hard to compete with, in terms of species and numbers. Wetlands in the Mediterranean region will be of big importance in the future. Climate change is prognosticated to cause prolonged droughts, hotter summers, and unpredictable precipitation, and more (Giorgo & Lionello 2008). The ecosystem services coming from the remaining wetlands will with high certainty in the future be even more important (Gardner et al 2015). Gialova can be said to be one of these wetlands, and by continuing the monitoring and protection of its birds, the wetland is more likely to continue to support both the birds and the human society in different direct and indirect ways.

5. Conclusions

The study showed that Gialova lagoon is a wetland supporting large numbers of migrating birds in spring. During the two-week long inventory in March, 27 species in the Bird directive, Annex I and 16 species in the EC red list were observed. The eastern part of the lagoon, with more freshwater, reeds and meadows, supported most focal species, and is also the most sensitive area. Agricultural activity and freshwater inflow are key factors to consider when managing these parts of the area. An inventory

30 covering the full spring with the same, or similar, methods should be the next step to have a complete comprehension of Gialova as a stopover for spring migrating birds. The compilation and analysis of wintering waterbirds in the lagoon for the last thirty years showed that the area holds large numbers of waterbirds during winter, but only one species showed a clear increase during this period (Greater flamingo (P. roseus)). Other studies have showed that temperature in winter is the most important factor behind numbers of wintering waterbirds, but also site-specific reasons are most likely contribute to the fluctuations, such as land use near the lagoon or the salinity. Data also showed that the wetland did not reach the threshold values to qualify as Ramsar-site of international importance. Even though, Gialova lagoon has values worth protecting since it is the first suitable stopover for birds crossing the Mediterranean Sea, it is a wetland in a dry region with few other wetlands, and it is a suitable place for ecotourism with possibility of supporting the local community.

Acknowledgement

A special thanks goes to Giorgos Maneas, manager at NEO, for help and valuable information throughout the process and especially during fieldwork in Gialova. A thanks also goes to Navarino Environmental Observatory for accommodation during fieldwork, and finally to Håkan Berg for supervising.

31

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Appendix I: Swedish translation of some of the most mentioned species in the thesis

Coot = Sothöna

Pochard = Brunand

Heron = Häger

Barn swallow = Ladusvala

Grebes = Doppingar

Greater flamingo = Större flamingo

Great cormorant = Storskarv

Teal = Kricka

Dabbling duck = Simand (till exempel kricka och gräsand)

Spur-winged lapwing = Sporrvipa

Waders = Vadare (till exempel snäppor, beckasiner och vipor)

Passerines = Tättingar

Gull = Måsfågel

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Appendix II: Species list from inventory, March 2017

Date:

Species 7/3 * 9/3 12/3 14/3 17/3 20/3 22/3 24/3 Mustached warbler 1 1 1 1 Kingfisher 15 22 18 9 9 10 15 9 Tawny pipit 2 1 2 3 Purple heron 4 1 Squacco heron 1 1 White eyed pochard 2 4 1 Bittern 1 Short-toed lark 2 Kentish plover 23 30 37 40 41 39 30 21 Hen harrier 1 1 2 1 1 Great white egret 20 17 28 17 15 16 14 9 Little egret 20 27 21 18 23 21 32 24 Black-winged stilt 6 20 20 32 41 Spur-winged lapwing 1 Pochard 1 9 1 Barn swallow 150 20 5 10 40 350 20 Slender-billed gull 2 1 2 1 Mediterranean gull 2 Osprey 1 1 1 1 1 Rough 1 55 85 81 74 48 7 Greater flamingo 132 174 194 86 50 63 64 76 Spoonbill 1 2 1 Glossy ibis 11 Golden plover 9 9 4 2 Sand martin 4 Caspian tern 9 Kentish tern 3 6 6 5 6 10 7 6 Wood sandpiper 1 9 4 8 Curlew 1 1 3 21 1 1 Saker falcon 1 Meadow pipit 30 70 70 40 50 40 80 50 Common coot 300 360 449 315 276 218 282 132 Marsh sandpiper 11 1 Garganey 12 63 70 24 15 12 14 Wigeon 118 128 247 181 178 188 211 141 Pintail 30 69 53 55 39 34 51 80 Redshank 4 35 22 33 5 2 4 3 Black tailed godwit 6 8

Non listed wetland species:

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Grey plover 11 23 21 15 12 5 8 10 Dunlin 31 30 41 35 21 13 11 4 Little stint 6 6 10 10 8 7 14 5 Temminck's stint 3 7 Little ringed plover 2 3 8 13 23 38 32 Water rail 5 8 7 2 4 3 6 5 Moorhen 3 1 6 1 1 2 2 common snipe 95 39 24 40 16 36 20 33 Greenshank 1 3 Shelduck 1 8 4 7 7 9 1 5 Teal 36 131 378 339 131 95 130 Shoveler 60 160 96 74 60 55 100 Gadwall 21 13 12 5 2 4 Great cormorant 72 83 115 84 84 88 83 Grey heron 23 32 16 22 19 37 13 Common sandpiper 2 1 1 1 1 1 2 3 Green sandpiper 3 3 1 1 4 4 2 Little grebe 18 21 6 6 6 5 10 Black necked grebe 3 3 7 3 3 4 Great crested grebe 7 5 8 8 8 7 5 Mallard 81 135 138 151 67 84 87 Yellow-legged gull 46 25 41 24 23 22 26 Black-headed gull 1 4 1 1 1 Spotted redshank 1 2 1 4 Mute swan 5 6 5 5 4 5 5 5 Crane 2 4 3 3 3 3 Little snipe 1 Whimbrel 1 1 1 Greylag goose 2

Non wetland birds: Hoopoe 1 Quail 1 1 1 Common swift 50 50 5 Fan tailed warbler 7 7 10 10 15 15 15 15 Water pipit 10 15 10 10 10 5 4 2 Red-throated pipit 2 3 1 2 3 Tree pipit 1 1 Common buzzard 6 5 9 6 9 4 3 5 Marsh harrier 8 8 10 5 6 4 3 4 Sparrow hawk 1 Kestrel 1 2 Peregrin falcon 2 1 Alpine Swift 70 45 4 Domestic pigeon 2 40 15 5 5

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Collared dove 5 2 2 2 2 2 House martin 100 10 5 3 Rock martin 30 15 5 Penduline tit 1 1 10 Robin 5 3 2 3 2 2 1 skylark 5 5 4 4 5 2 2 crested lark 30 30 15 25 25 25 20 white wagtail 100 70 40 40 30 50 40 gray wagtail 1 3 1 1 Yellow wagtail 1 5 10 70 20 70 20 Black redstart 1 1 1 wheatear 2 1 1 5 5 5 5 Black-eared wheatear 1 Stonechat (maurus) 3 6 2 2 2 3 3 songtrush 10 15 5 5 3 3 2 blackbird 2 1 2 2 3 blackcap 40 50 20 25 25 35 20 sardinian warbler 10 5 5 5 5 5 3 sedge warbler 2 2 3 2 4 8 25 Great reed warbler 5 5 cetti warbler 15 15 15 15 15 15 15 Subalpine warbler 1 1 chiffchaff 7 15 15 20 15 15 10 great tit 1 2 1 1 2 3 Wren 1 magpie 4 2 1 2 1 2 1 jay 2 2 1 1 1 1 crow 7 10 10 15 15 20 20 raven 2 2 1 1 2 1 starling 30 5 5 5 3 2 house sparrow 40 20 10 20 10 20 20 Spannish sparrow 20 10 10 20 chaffinch 30 30 20 10 10 5 5 linnet 15 15 15 10 15 15 15 goldfinch 40 40 30 30 20 15 15 Serin 1 2 greenfinch 20 20 5 10 10 5 5 reedbunting 15 2 3 5 5 5 5 Corn bunting 10 15 10 10 10 10 15 Cirl bunting 1 Nr of species per day 79 80 85 94 83 92 87

*Only try out visit, no formal counting

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