Eleven new spider species discovered from coastal grasslands of Estonian EBA during the era of biodiversity loss

29 September 2023

On 28 September 2023, Mylene Martinez, a PhD student from the Estonian University of Life Sciences, presented SHOWCASE preliminary findings at the 18th Eurasian Grassland Conference 2023. The conference was held in Szarvas, Hungary on 25-28 September, under the theme of “Conservation and management of grasslands in transforming landscapes”. Mylene's research focused on spiders and the sustainable management of Estonian coastal grasslands, a critical habitat adjacent to the Baltic Sea.

Over the course of two intensive years of field- and laboratory work, Mylene employed two collection methods: pitfall traps in 2021 and vacuum sampling in 2022. Her efforts yielded approximately 13,000 specimens and encompassing 199 species, which accounts for roughly 35 % of all spider species in Estonia.

During her presentation, Mylene presented eleven previously unrecorded spider species from the Estonian coastal grasslands in SHOWCASE's Estonian Experimental Biodiversity Area (EBA). Notably, several of these species had never been documented in the Baltic states. Mylene's research also shed light on potential climate-induced range shifts in spider populations, as suggested by the presence of Agroeca dentigera and Rugathodes instabilis. Furthermore, her study discovered the northernmost occurrence of the invasive species Mermessus trilobatus in the Estonian coastal grasslands, indicating its expanding distribution range in Europe.

Her study findings revealed that grassland abandonment had a positive impact on the abundance of the second generation - juvenile spiders, though not on adult spiders. Mylene stressed the significance of grassland abandonment for enhancing species richness and diversity within spider assemblages in the Estonian coastal grasslands.

Based on her preliminary results, Mylene concluded that undisturbed areas or selective management are necessary for the conservation of spider fauna in the Baltic Sea coastal grasslands. Continuous monitoring of spiders and other ground-dwelling macroarthropods is crucial for increasing effectivness of biodiversity conservation in coastal areas, particularly in the face of global environmental changes.

Photo: Mylene presenting her SHOWCASE research results in the visitor centre of the Körös-Maros National Park.