This thesis investigates three endangered dragonfly species in Andalusia, Spain: Onychogomphus cazuma, Onychogomphus costae and Lestes macrostigma. Focused on Málaga province, the research integrates population assessments, habitat analyses, and behavioral studies to inform conservation strategies for these flagship species.
Field work period: Mid April to Mid July.
Basement: El Chorro, at a rural house (pending price for accommodation).
Displacement: bicycle (El Chorro). There is a train between Málaga city and El Chorro.
Receiving Entity: Andalusian Dragonfly Recording Scheme (ROLA / AEA El Bosque Animado).
Supervisor in Andalusia: Florent Prunier (ROLA)
We are seeking a highly motivated student with prior experience in entomology / odonatology. The ideal candidate will be independent and able to take responsibility for field surveys while working under close supervision.
Case study #1 : Onychogomphus cazuma
This case study will be the main focus of the survey.
Taxonomy and Distribution. Onychogomphus cazuma is a rare gomphid dragonfly species endemic to Spain. It was described relatively recently compared to other members of the genus, and its known distribution is highly restricted. Historically, it was thought to be confined to a few localities in eastern Spain, but recent discoveries have extended its range. The El Chorro population is particularly significant for conservation, as it represents a southern range extension and is genetically distinct from populations in eastern Spain.
Population Status and Conservation. The only known population in Southern Spain is located in Málaga province (El Chorro). Prunier and De Knijf (2023) identified three closely situated sites within a two-kilometer radius. The species is considered endangered due to its limited distribution, small population sizes, and vulnerability to habitat alteration. Recent monitoring suggests that exuviae counts may underestimate the true population size, as adult counts in 2024 indicate a higher number than previously thought.
Habitat and Ecology. Onychogomphus cazuma inhabits clean, well-oxygenated seepages with permanent water. It prefers sites with moderate flow and is potentially sensitive to water quality and habitat disturbance.
– Population Estimation: Exuviae counts: Biweekly surveys. Adult transects: Regular monitoring at breeding sites. Capture-Mark-Recapture (CMR): Adult tracking for population estimate, local dispersal between sites, adult survival.
– Habitat Requirements: Water parameter quantification (e.g., temperature). Microhabitat characterization (substrate, flow, vegetation).
– Behavioral Ecology: Logging marked individuals to assess: Territory choice. Thermoregulation behaviours . Intra-/inter- specific competition.
– Habitat Selection: Odonata transects in adjacent streams/rivers to identify habitat specialization.
References
Prunier, F., & De Knijf, G. (2023). Discovery of a population of Onychogomphus cazuma in Andalusia, Spain. Notulae Odonatologicae, 10(2), 60-66.
De Knijf G., Díaz-Martínez C., Billqvist M., van Grunsven R.H.A., Prunier F. & Vinko D. 2023. Onychogomphus cazuma. The IUCN Red List of Threatened Species 2023: e.T177247357A208811110. Accessed on 13 December 2023. https://www.iucnredlist.org/species/177247357/208811110
Case study #2 : Onychogomphus costae
Taxonomy and Distribution. Onychogomphus costae is another member of the Gomphidae family, found in the western Mediterranean region, including parts of North Africa and southern Europe. In Spain, it is primarily distributed in the southern provinces, with notable populations along the Guadalhorce River in Málaga.
Population Status and Conservation. The Guadalhorce River, especially below the dam at El Chorro, is recognized as a stronghold for O. costae in Málaga province (Prunier, 2018). The species is considered locally threatened, primarily due to habitat loss, water abstraction, and river regulation. Despite these pressures, the El Chorro area supports robust populations, with key sampling sites located 3 and 9 km apart.
Habitat and Ecology. Onychogomphus costae favors slow-flowing rivers with silty sandy or gravelly bottoms. It is less sensitive to moderate human disturbance than some other gomphids but still requires stable water levels. The species is often found in association with riparian vegetation, which provides shelter.
Research Objectives & Methodology
– Population Monitoring. Weekly exuviae and adult transects.
– Comparative density analysis across sites.
– Habitat Connectivity. GIS mapping of dispersal corridors between sites.
References
Prunier, F. (2018). Onychogomphus costae in Andalusia, southern Spain – mapping an overlooked species (Odonata: Gomphidae). Odonatologica, 47(1/2), 1-22.
Prunier, F., Billqvist, M., De Knijf, G., van Grunsven, R.H.A. & Vinko, D. 2024. Onychogomphus costae (Europe assessment). The IUCN Red List of Threatened Species 2024: e.T60291A208819737. https://apistaging.iucnredlist.org/en/species/60291/208819737. Accessed on 27 June 2025.
Case study #3 : Lestes macrostigma
Taxonomy and Distribution. Lestes macrostigma (the “Dark Spreadwing”) is a damselfly (Zygoptera) with a broad but fragmented distribution across the Mediterranean basin, extending from the Iberian Peninsula to Central Asia. In Spain, its distribution is severely fragmented, with main populations along the Atlantic coast of Andalusia, in the interior “La Mancha Húmeda” wetlands, and in saline lagoons of the Antequera Depression in Málaga province.
Population Status and Conservation. Lestes macrostigma is listed as Vulnerable (VU) in the Spanish Red List of Invertebrates and is considered Near Threatened (NT) at the European level. Its populations are small and highly localized, with only a few sites in Andalusia supporting regular and continuous observations. The Arraijanal Canal near Málaga is a notable peri-urban population, discovered in 2015, and is now one of the most consistently monitored sites for the species. Population numbers fluctuate dramatically, influenced by habitat management, hydroperiod, and spring rainfall.
Habitat and Ecology. Lestes macrostigma favors shallow, temporary or semi-permanent water bodies with abundant emergent vegetation, especially sea club-rush (Bolboschoenus maritimus), which is its preferred plant for oviposition. The species is adapted to subsaline conditions and can survive in habitats with variable water levels and salinity. Its ability to disperse and colonize new sites is notable, but successful reproduction depends on the maintenance of suitable vegetation and water conditions.
The Arraijanal Canal, a recently created wetland, demonstrates the species’ capacity to colonize and persist in peri-urban environments, provided habitat management is appropriate and disturbance is minimized.
Research Objectives & Methodology
– Population Dynamics: Weekly surveys to track emergence patterns and abundance.
– Habitat Management: Water physicochemical profiling (pH, salinity). Vegetation structure analysis and restoration recommendations.
– Rainfall and breeding success. Correlation between Spring rainfall and Population size.
References
Prunier, F., Ripoll, J., & Winter, P. (2025). A peri-urban population of Lestes macrostigma in Spain (Odonata: Lestidae). Notulae odonatologicae, 10(5), 165-175.
Prunier, F., Billqvist, M., De Knijf, G., van Grunsven, R.H.A. & Vinko, D. 2024. Lestes macrostigma (Europe assessment). The IUCN Red List of Threatened Species 2024: e.T165480A208836704. https://apistaging.iucnredlist.org/fr/species/165480/208836704. Accessed on 27 June 2025.
Commentaires récents