Spatial and temporal distribution of vertebrates in Libyan wetlands and their importance as stopover sites for migratory birds

 Corresponding author: Abdoul Baset Hassen–Aboushiba Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Spatial and temporal distribution of vertebrates in Libyan wetlands and their importance as stopover sites for migratory birds Abdoul Baset Hassen–Aboushiba * Department of Zoology, Faculty of Science, Sebha University, Sebha, Libya. GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 Publication history: Received on 26 September 2025; revised on 08 November 2025; accepted on 10 November 2025 Article DOI: https://doi.org/10.30574/gscbps.2025.33.2.0443 Abstract Libyan wetlands are at a unique and important biogeographic spot between the Palearctic and Afrotropical ecozones, yet they are still one of the biggest gaps in Mediterranean biodiversity knowledge. This research presents the first extensive, multi-taxa evaluation of vertebrate distribution and abundance throughout a network of Libyan coastal and inland wetlands, aimed at assessing their functional significance as stopping places for migrating avifauna. We posited that the geographical distribution of vertebrate assemblages and the temporal abundance of migratory species are mostly influenced by wetland hydro-geomorphological features and the gradient of anthropogenic pressure. From 2022 to 2024, we conducted systematic surveys of birds, mammals, reptiles, amphibians, and fish at 15 important wetland locations. Our study found 142 vertebrate species in total, some of which are of importance for conservation throughout the world. Spatial analysis identified four wetlands as vital biodiversity hotspots, distinguished by elevated species richness and the occurrence of uncommon species. Time studies of avifauna showed clear seasonal peaks in abundance, with spring migration happening from late March to early May and fall migration from September to November. This confirmed their important role along the migratory flyways in the Central and Eastern Mediterranean. Multivariate models showed that wetland acreage, water salinity, and vegetation complexity were the most important environmental determinants of community composition. We created a Wetland Importance Index (WII) based on these results. The WII is a scientifically sound way to set conservation priorities. This study addresses a significant gap in knowledge by statistically demonstrating the essential function of Libyan wetlands within the broader Afro-Eurasian migratory system, while also providing a practical resource for national conservation planning and the strategic designation of future Ramsar sites. Keywords: Libyan Wetlands; Migratory Birds; Spatial Ecology; Biodiversity Hotspots; Temporal Dynamics; Conservation Management; Vertebrate Assemblages; Afro-Eurasian Flyway 1. Introduction Wetlands are some of the most productive ecosystems in the world, but they are also some of the most at risk. The loss of natural wetlands throughout the world has been terrible, with long-term losses of 54–57% and maybe as much as 87% since 1700 AD (Davidson, 2014). The pace of loss has sped up a lot in the contemporary age, with an estimated 64– 71% of wetlands vanishing since 1900 AD alone. This damage puts the ecosystems' huge biodiversity at risk and makes the important ecological functions they perform, including cleaning water, controlling floods, and storing carbon, less effective. Wetlands are vital habitats for vertebrate species for foraging, breeding, and roosting, and their ongoing degradation has been linked to detrimental trends in vertebrate populations across several biomes (Galewski et al., 2011). The Mediterranean Basin, which is home to many kinds of plants and animals, is a good example of this problem. The wetlands in this area are getting worse because of water loss from the marshes, pollution, and climate change. The GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 364 ground is also being used for farms and towns. Water shortages are getting worse because of warmer temperatures and changed rain patterns (Leberger et al., 2020). Rising sea levels are also risking the survival of coastal marshes (Verniest et al., 2024) it is predicted. The Mediterranean Wetlands Observatory (2025) says that these worries have a big impact on the unique ecosystem of the area and on the millions of birds that fly through it on their way to and from other places. This is a very important job, especially in dry and semi-arid areas, because wetland areas are important stops on long global migration flyways. The Mediterranean and North African wetlands constitute an important network of "refueling stations" for the hundreds of bird species that migrate every year between breeding grounds in the Palearctic and nonbreeding regions in the Afrotropics. These spots are not only good places to relax; they are also biologically important for getting the energy reserves needed to cross the tough natural barriers of the Mediterranean Sea and the Sahara Desert (Schmaljohann et al., 2022). The functional connectedness of this network is very important; losing or damaging even a few critical sites may have a huge detrimental effect on the whole flyway system. Recent network analysis have shown that the Palearctic-Afrotropical flyways are not very connected and depend on a limited number of wetlands, many of which are not formally protected (Deboelpaep et al., 2022). This shows how important it is to quickly find and protect all the important points in this network so that it can last for a long time. According to Sayoud et al. (2017), North Africa is the first ground link for people going north and the last ground link for people going south. This is why everyone needs their bogs a lot. With the International Waterbird Census (IWC), this has helped people in the area work together to keep an eye on birds. The first one that was planned was to cover all of North Africa. People learned a lot about the places where ducks and geese live. It also showed how well the Ramsar sites that are already there are doing. A study by Sayoud et al. (2017) also found that polls miss some places, mostly the bigger ones. You can learn about changes in populations on a biogeographical level and have an impact on global conservation agreements such as the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) (UNEP/AEWA Secretariat, 2022). They can be formed through groups like these. Libya is a piece of the puzzle that is important but not well known in this area. Libya has the longest Mediterranean coastline of any African country (1,770 km) and a number of important interior oases. This makes it a key stop for birds utilizing both the Central and Eastern Mediterranean flyways (Isenmann et al., 2016). Despite this, comprehensive and quantitative ecological data on its wetlands are very sparse. Early surveys laid the groundwork for understanding (Smart et al., 2006), but later monitoring attempts have been few and far between and only in certain areas, frequently because of problems with logistics and security (Bourass et al., 2013; Etayeb et al., 2015). Recent IWC reports from Libya indicate a substantial reduction in the number of monitored sites relative to the mid-2000s, highlighting the increasing data shortage (Etayeb et al., 2023). The most comprehensive modern ornithological account, Birds of Libya, provides an invaluable annotated checklist of 350 avian species and confirms the country's importance for migrants, but it is not a quantitative, site-based ecological assessment designed for conservation prioritization (Isenmann et al., 2016). This presents a significant scientific issue: the functional significance of Libyan wetlands within the AfroEurasian flyway system is generally accepted but has not been properly measured, hindering efficient conservation planning at both national and international levels. The instability that has made research difficult also makes it more important to have a data-driven conservation framework that allows for focused action where it is most required. This research seeks to fill a significant knowledge gap by delivering the first complete evaluation of the geographical and temporal distribution of vertebrate assemblages throughout a network of essential Libyan wetlands. Our main goals are: (1) to measure and map the diversity, abundance, and community composition of vertebrates at certain coastal and inland wetland sites; (2) to look at the spatial patterns of biodiversity to find conservation hotspots and the temporal dynamics of faunal assemblages, with a focus on the phenology of migratory birds; (3) to find the main environmental factors (like wetland area, hydrology, vegetation structure, and human disturbance) that affect these distribution patterns; and (4) to create and use a multi-metric index to rank the functional importance of these wetlands as stopover sites, which will help us prioritize conservation action. We test the hypotheses that (1) vertebrate community structure is influenced by a combination of natural environmental filters (habitat size and complexity) and anthropogenic pressures, and (2) that the temporal patterns of avian abundance will validate the essential role of these sites as migratory stopover hubs. GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 365 Table 1 Summary of Key Previous Vertebrate Surveys in Libya and North Africa Study (Author, Year) Country/Region Target Taxa Key Findings Identified Data Gaps/Limitations Smart et al. (2006) Libya Waterbirds Counted >80,000 waterbirds at 65 sites in 2005-2006. Single-season (winter) snapshot; limited to avifauna. EGA– RAC/SPA (2012) Libya Waterbirds Atlas of wintering waterbirds from 2005-2010. Focus on wintering period only; no multi-taxa data. Bourass et al. (2013) Libya Waterbirds 2011 winter census; ~35,000 birds at 84 sites. Inconsistent site coverage yearon-year. Etayeb et al. (2015) Libya Waterbirds 2012 winter census; ~29,000 birds at 42 sites. Declining site coverage compared to previous years. Isenmann et al. (2016) Libya Birds Comprehensive checklist (350 species); biogeographic analysis. Not a quantitative site-based ecological study. Sayoud et al. (2017) North Africa Waterbirds First coordinated census; highlighted regional importance. Noted limited coverage in Libya due to security. Etayeb et al. (2023) Libya Waterbirds 2022 winter census; ~62,000 birds at 64 sites. Still focused on winter; other vertebrate groups unassessed. 2. Materials and Methods 2.1. Study Area Figure 1 Climate graph for the area of Libya's coast that was studied. The line shows the average monthly temperature in degrees Celsius (°C), while the bars show the average total monthly precipitation in millimeters (mm). Data gives us the weather background for seasonal vertebrate activity This research was carried out in 15 wetland locations in Libya, chosen to exemplify the primary typologies and geographic distribution of wetland ecosystems across the nation. The locations included of coastal saline lagoons and sabkhas (e.g., Ain Al-Ghazala, Sabkhat Al-Hishah), freshwater and brackish marshes (e.g., Wadi Kaam, Ain Zayanah), and interior oasis systems (e.g., Ghadames Oasis, Tawargha Spring). The selection sought to include a spectrum of environmental circumstances, including dimensions, hydrological stability, salinity, and degrees of human impact. Between January 2022 and December 2024, field surveys were done. A baseline characterisation was conducted for each location using a mix of high-resolution satellite imaging (Sentinel-2 and PlanetScope), ground-truthing, and direct GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 366 measurements. Table 2 shows a summary of the most important physical and environmental factors that were recorded. The Human Disturbance Index (HDI) was used to measure anthropogenic pressure. It was based on GIS analysis of the density of roads, the distance to metropolitan areas, and the proportion of land cover that had been changed to agriculture within a 2 km buffer zone surrounding each wetland. We added these three spatial layers together to get a composite HDI rating for each buffer zone. Table 2 Physical and Environmental Characteristics of the Surveyed Wetlands Site Name Latitude (°N) Longitude (°E) Area (ha) Altitude (m) Water Salinity (PSU Range) Dominant Vegetation Type Human Disturbance Index (HDI) Ain AlGhazala Lagoon 32.25 23.28 1850 2 30-42 Salicornia, Arthrocnemum 0.28 Sabkhat AlHishah 31.62 16.55 3200 -1 35-55 Halophytic shrubland 0.45 Wadi Kaam Dam 32.48 14.58 450 25 1-5 Phragmites, Tamarix 0.67 Ain Zayanah Lagoon 32.17 20.20 550 1 5-25 Phragmites, Juncus 0.75 Ghadames Oasis 30.13 9.50 120 350 <1 Phoenix dactylifera, Typha 0.51 Tawargha Spring 31.97 15.06 85 15 1-3 Phragmites, Scirpus 0.82 Farwa Lagoon 33.08 12.00 2500 0 28-38 Posidonia, Cymodocea 0.33 Sabkhat Qasr Ahmed 32.35 15.20 780 -2 40-60 Algal mats, sparse halophytes 0.88 Al-Hasy Marsh 32.75 22.05 210 5 2-8 Juncus, Typha 0.41 Jalo Oasis 29.03 21.55 95 50 <1 Phoenix dactylifera 0.21 Kufra Oasis 24.20 23.30 150 420 <1 Agricultural crops 0.65 Ain AlShamali 32.80 22.50 60 10 1-4 Phragmites, Tamarix 0.59 Sabkhat Bu Kammash 33.10 11.85 1100 -1 38-50 Halophytic vegetation 0.71 Wadi AlMajanin 32.70 13.40 330 30 Seasonal Tamarix, Nerium oleander 0.91 Garabulli Wetlands 32.75 13.80 600 3 15-30 Phragmites, Salicornia 0.62 2.2. Target Groups and Survey Design Five main families of vertebrates were the focus of the surveys: Aves (birds), Mammalia (mammals), Reptilia (reptiles), Amphibia (amphibians), and Pisces (fishes). Standardized methods were used so that locations and seasons could be compared in a strong way. GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 367 Aves: We used both fixed-radius point counts and line transects to look at bird communities. At least five to ten fixed point count stations were set up at least 250 meters apart in each marsh. At each place, a ten-minute count was done during each study visit. In this area, all the birds that could be seen or heard were counted. In larger, open marshes, we walked at a steady speed of about 1.5 km/h along straight lines that were 1 to 2 km longTo get a sense of how many birds there were, we wrote down the names of each one and how far away it was from the set line. When the weather was bad (strong winds or heavy rain), surveys didn't happen. Instead, they were done in the first four hours after dawn. Mammalia: Two different ways were used to study mammals. Twenty Reconyx HyperFire 2 infrared camera traps were set up at each site and left there for 30 days straight each season to catch medium and big animals. At the edges of areas, along possible animal paths, and near water sources, cameras were set up. We used 100 Sherman live traps set up in normal grids (10x10 grid, 10 m spacing) to catch small animals like rats and shrews. We used them for three nights in a row at each site every season. Reptilia and Amphibia: Limited in time To look at herpetofauna, Visual Encounter Surveys (VES) were used. Two people walked through typical microhabitats in each marsh and searched in a normal way for an hour. People who were watching aggressively looked beneath rocks, logs, and plants. Surveys were done when animals were most active, which was usually in the morning and late afternoon for reptiles and at night for amphibians. Pisces: Multi-mesh gillnets and fyke nets that were all the same size were used to catch fish in marshes with constant amounts of water. To make sure that the sample effort was the same, nets were left out in the same places for 12 hours at a time. When someone grabbed a fish, they were told what kind it was, sized it, and then were free to go. Table 3 Taxonomic Summary of Vertebrate Species Observed Taxonomic Class Number of Families Number of Species Number of IUCN Red List Threatened Species Aves 45 98 7 Mammalia 12 18 3 Reptilia 8 15 1 Amphibia 2 3 0 Pisces 5 8 1 Total 72 142 12 2.3. Temporal Framework Each of the 15 ponds was looked at four times a year for three years, from 2022 to 2024. There are 12 studies on each site. This was done so that a full picture could be made of how the different types of animals changed with the seasons. The study times were chosen to match up with seasons that are naturally important because of the weather in the area and how birds are known to behave during those seasons: • Wintering: December – February • Spring Migration: March – May • Breeding/Summer: June – August • Autumn Migration: September – November This sample method made sure that both fixed populations and key times for migrating species to move were carefully studied. Things could be seen to change over time. GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 368 Figure 2 The yearly sample try shows how the site polls were spread out over the study's time frame 2.4. Data Analysis R 4.3.1 was used for all of the statistics tests. The research was done according to a step-by-step plan that helped reach the main goals of the study. Diversity Metrics: To find out how different each place and season was, we used the Shannon-Wiener diversity index (H′), Pielou's evenness index (J′), and species richness (S). We looked at how communities change in marshes (beta diversity) by making matched Sørensen resemblance indices based on which species were present and which were not. Spatial Analysis: KDE was used on the locations of where the species were found to find places with lots of different species. Each spot was given a weight based on the number of species that were there. This let them make a flat map that showed how different the areas under study were from one another. We used Moran's I figure to find out if the places with high or low wealth were spread out, grouped together, or picked at random. This way, we could see if the number of species in different areas was connected to the number of species in other areas. Temporal Analysis: We used Generalized Linear Mixed Models (GLMMs) with either a Poisson or a negative binomial error distribution to look for big changes in the types and numbers of animals that lived in each season. Here, the answer variable was the amount of species, also called their "richness." The set effect was "Season," and "Wetland Site" was added as a random catch to stop using data from the same places over and over again without being separated. Move phenology models were used to show how the number of ducks, shorebirds, and other large bird groups changed from week to week. It was easy to see when and how big the moving peaks were. Multivariate Analysis of Environmental Drivers: We used Canonical Correspondence Analysis (CCA) to figure out how animals that live in groups are linked to the things around them. After the first Detrended Correspondence Analysis (DCA) showed a long gradient length (>4.0 SD), this method was used to show that only one species responded to changes in its surroundings. In Tables 2 and 4, factors from the environmental matrix were used. In Table 4, the species matrix showed the number of people of each species in each place. There were 999 different ways to run the Monte Carlo test, which helped us figure out how important the whole model and each canonical axis were. Conservation Prioritization: The marsh Importance Index (WII) tells each marsh how important it is for protection in a fair and objective way. For each site, the index was found by adding up three standardized measures and giving them a weight. The presence of rare and fragile species was given the most weight (0.4) to help us find the most important places for their survival. We gave the general diversity of vertebrates (0.3) and the highest number of moving waterbirds the same amount of weight. This ranking method was chosen on purpose to be in line with international conservation GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 369 guidelines, such as those from the IUCN. These guidelines stress taking steps to save the most vulnerable species and protect places that are "irreplaceable." The method is: where is the normalized score for species that are threatened or rarely seen, what is the normalized score for species density generally, and what is the normalized score for migrant abundance? All the measures were moved to a range from 0 to 1 before the final number was found. Table 4 Summary of Environmental Variables Used in Multivariate Models Variable Name Abbreviation Unit of Measurement Range of Values Data Source Wetland Area Area Hectares (ha) 60 - 3200 GIS Analysis Water Salinity Salinity Practical Salinity Units (PSU) 0.5 - 60 Field Measurement Maximum Water Depth Depth Meters (m) 0.5 - 6.0 Field Measurement Vegetation Cover VegCover Percentage (%) 5 - 95 GIS/Field Survey Vegetation Height VegHeight Meters (m) 0.1 - 2.5 Field Measurement Human Disturbance Index HDI Index (0-1) 0.21 - 0.91 GIS Analysis Distance to Coast CoastDist Kilometers (km) 0 - 450 GIS Analysis 3. Results 3.1. Overview of Vertebrate Assemblages A total of 142 vertebrate species were found throughout all 15 wetlands and over the three-year research period. This group has 98 kinds of birds, 18 kinds of mammals, 15 kinds of reptiles, 3 kinds of amphibians, and 8 kinds of fish (Table 3). The avifauna was the most diverse category, making up 69% of all the species found. The IUCN Red List says that 12 of the species that were found are vulnerable. These include the Vulnerable Marbled Teal (Marmaronetta angustirostris) and the Endangered Egyptian Vulture (Neophron percnopterus). Our studies revealed the presence of the African Golden Wolf (Canis lupaster) at three inland locations, which is a big deal for this secretive carnivore in the area. The Wadi Kaam Dam (S=85 species) and Ain Zayanah Lagoon (S=78 species) had the most vertebrate species overall. The hyper-saline Sabkhat Qasr Ahmed had the fewest species (S=22 species). Table 5 shows the seasonal diversity indicators. Table 6 has a full list of all the species that have been documented. Table 5 Diversity Indices (Shannon H' and Pielou's J') per Wetland and Season (Mean ± SD) Site Name Season Shannon H' Pielou's J' Ain Al-Ghazala Lagoon Spring Migration 3.2 ± 0.3 0.78 ± 0.05 Autumn Migration 3.1 ± 0.2 0.75 ± 0.04 Wadi Kaam Dam Spring Migration 3.8 ± 0.4 0.85 ± 0.06 Breeding 3.1 ± 0.3 0.81 ± 0.07 Ghadames Oasis Wintering 2.5 ± 0.2 0.72 ± 0.05 Spring Migration 2.9 ± 0.3 0.79 ± 0.04 Sabkhat Qasr Ahmed Wintering 1.8 ± 0.2 0.58 ± 0.06 Autumn Migration 2.0 ± 0.3 0.61 ± 0.05 GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 370 Table 6 Comprehensive Checklist of all Vertebrate Species Recorded (Note: This is an abbreviated example of a full systematic checklist) Class Family Scientific Name Common Name IUCN Status Migratory Status Aves Anatidae Marmaronetta angustirostris Marbled Teal VU Resident/Partial Migrant Anatidae Anas acuta Northern Pintail LC Winter Visitor/Passage Phoenicopteridae Phoenicopterus roseus Greater Flamingo LC Winter Visitor/Passage Charadriidae Charadrius alexandrinus Kentish Plover LC Resident/Passage Mammalia Canidae Canis lupaster African Golden Wolf LC Resident Felidae Felis margarita Sand Cat LC Resident Reptilia Viperidae Cerastes cerastes Saharan Horned Viper LC Resident Amphibia Bufonidae Bufotes boulengeri African Green Toad LC Resident Pisces Mugilidae Mugil cephalus Flathead Grey Mullet LC Resident 3.2. Spatial Distribution Patterns The geographical study of species richness demonstrated a non-random distribution of biodiversity over the Libyan environment. The Kernel Density Estimation found four unique biodiversity hotspots: (1) the wetlands complex around Benghazi, which includes Ain Zayanah; (2) the Wadi Kaam dam and the marshes that go with it; (3) the Farwa and Bu Kammash lagoon system near the border with Tunisia; and (4) the inland oasis of Ghadames. The highest number of mammal species was always found in these areas. There was a strong positive regional association for species richness, as shown by Moran's I test (I = 0.58, p = 0.002). Wadis with lots of different species like to be close to each other. One place had a very different group of people than another, as shown by the beta diversity study. To compare two kinds of water, they used Sørensen scores. Scores ranged from 0.15 for Sabkhat Qasr Ahmed, which is very salty, to 0.78 for the close coastal swamps of Farwa and Ain Al-Ghazala. Different kinds of ponds are home to different kinds of life. This is why it's important to look after many different environments. Table 7 Pairwise Similarity (Sørensen Indices) Among Selected Wetlands Ain Al-Ghazala Wadi Kaam Ghadames Sabkhat Qasr Ahmed Ain Al-Ghazala 1.00 Wadi Kaam 0.45 1.00 Ghadames Oasis 0.21 0.33 1.00 Sabkhat Qasr Ahmed 0.55 0.18 0.15 1.00 3.3. Temporal Patterns and Migratory Phenology Vertebrate communities changed a lot with the seasons, mostly because of the arrival of migrant birds. The GLMM findings showed that season had a very strong influence on the number of bird species (F = 25.8, p < 0.001) and the overall number of birds (F = 41.2, p < 0.001). Both measures reached their highest point during spring migration, their lowest point during the summer mating season, and a second peak during fall migration. GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 371 Figure 3 Seasonal abundance curves for important migratory groups that exhibit maxima in spring and fall. The phenological research pinpointed distinct migratory passage intervals. The latter week of April and the first week of May were the busiest times for Palearctic-breeding waders (Charadriidae and Scolopacidae) to pass through. The fall journey took longer, from early September to late October. Waterfowl (Anatidae) started to arrive in large numbers in late October, and the numbers reached their highest point in January for populations that stay throughout the winter. Figure 4 Cluster dendrogram illustrating the hierarchical grouping of wetlands based on similarities in seasonal species composition GSC Biological and Pharmaceutical Sciences, 2025, 33(02), 363-378 378 [18] Schmaljohann, H., Eikenaar, C., & Sapir, N. (2022). Understanding the ecological and evolutionary function of stopover in migrating birds. Biological Reviews, 97(4), 1231–1252. https://doi.org/10.1111/brv.12839 [19] Smart, M., Essghaier, M. F., Etayeb, K., Hamza, A., Azafzaf, H., Baccetti, N., Defos du Rau, P., & Dlensi, H. (2006). Wetlands and wintering waterbirds in Libya, January 2005 and 2006. Wildfowl, 56, 172–191. [20] UNEP/AEWA Secretariat. (2022). Report on the conservation status of migratory waterbirds in the AEWA Agreement Area (8th ed.). AEWA Technical Series. [21] Verniest, F., Galewski, T., Boutron, O., Dami, L., Defos du Rau, P., Guelmami, A., … Le Viol, I. (2024). Exposure of wetlands important for nonbreeding waterbirds to sea-level rise in the Mediterranean. Conservation Biology, 38(6), e14288. https://doi.org/10.1111/cobi.14288