Translocation of keystone species may not mean translocation of keystone effect

Diversity and composition of mixed-ploidy unisexual salamander assemblages reflect the key influence of host species

Understanding processes that govern and sustain biological diversity is a central goal of community ecology. Unisexual complexes, where reproduction depends on sperm from males of one or more bisexual host species, are rare and the processes driving their diversity and structure remain poorly understood. Unisexual Ambystoma salamanders produce distinct biotypes ('genomotypes') depending on which bisexual species they 'steal' sperm from. This reproductive mode should generate distinct assemblages depending on the locally available bisexual host species. Yet, how availability and relative abundance of multiple bisexual hosts influences composition and diversity of natural unisexual assemblages at local or regional scales remains unknown. We hypothesize that host identity most directly drives local assemblage composition, with host variation associated with increased beta and gamma diversity within unisexuals. We collected genetic samples from Ambystoma salamanders across Pelee Island, Ontario, Canada (2015-2022). Two host species were identified (A. texanum and A. laterale) with nine sites having a single host and one site having both. Unisexual assemblages were grouped into four clusters by similarity, with host identity being a key determinant. Gamma diversity increased as a result of distinct host-specific assemblages forming at different sites on the island (i.e., high beta diversity). Assemblage composition, but not diversity, was correlated with relative host abundance, which may reflect matching niche requirements between host and unisexual forms they produce. Our results demonstrate that diversity and structure of unisexual assemblages are clearly shaped by their host(s) and such systems may serve as models for studying how biotic interactions shape ecological communities.

The role of ant nests in European ground squirrel's (Spermophilus citellus) post-reintroduction adaptation in two Bulgarian mountains

The European ground squirrel (Spermophiluscitellus) is a vulnerable species, whose populations are declining throughout its entire range in Central and South-Eastern Europe. To a great extent, its conservation depends on habitat restoration, maintenance and protection. In order to improve the conservation status of the species, reintroductions are increasingly applied. Therefore, researchers focus their attention on factors that facilitate these activities and contribute to their success. In addition to the well-known factors like grass height and exposition, others, related to the underground characteristics, are more difficult to evaluate. The presence of other digging species could help this evaluation. Here, we present two reintroduced ground squirrel colonies, where the vast majority of the burrows are located in the base of anthills, mainly of yellow meadow ant (Lasiusflavus). This interspecies relationship offers numerous advantages for the ground squirrel and is mostly neutral for the ants. The benefits for the ground squirrel, including reduced energy demand for digging, as well as additional surveillance and hiding places available, could greatly enhance the post-reintroduction adaptation process.