Ants are known to contribute to the physical and chemical improvement of the soil. In this context, the hypothesis put forward is that ants improve the nitrogen (N) supplementation necessary to ensure the high primary production measured in the Lamto savannah. Recent investigations in the humid savannah ecosystem showed that ant nests’ association with perennial grasses enhances their growth, productivity, and microorganism activity. This study aimed at understanding the effect of ant nests on organic matter (OM), carbon (C), and N flux beneath grass tufts. Under each grass tuft chosen to carry out this study, soil samples were taken from the depths of 0–10 cm using an auger at shrubby, clear grassy, and transitional grassy savannah. The analytical method by incineration of the loss on fire was used to determine the OM amount. The Kjeldahl method was used to determine the total N amount in the soil under grass tufts. The results showed that these components’ amount is higher beneath grass tufts associated with ant nests than those not associated with ant nests. The presence of ant nests increases OM and C amount in the soil under Hyparrhenia diplandra tufts than Andropogon schirensis, and Loudetia simplex tufts. In contrast, N amount is higher under L. simplex tufts than A. schirensis; but mean under H. diplandra. The carbon/nitrogen ratios less than 10 indicate high OM mineralization under grass tufts associated with ant nests. This provides the plants with an adequate supply of nutrients
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RBINS Staff Publications 2023
With only three named species, Antarctica is the continent with the least explored kinorhynch biodiversity. The present contribution provides the most comprehensive study of Antarctic kinorhynchs collected along the coast of the West Antarctic Peninsula. Quantitative samples were collected in three regions along the Peninsula: in Andvord Bay Fjord at the Danco Coast, in the Gerlache Strait, and on the open continental shelf west of the Peninsula. Comparison of the sampling areas suggests that the highest kinorhynch abundance was in the Gerlache Strait, where kinorhynchs were over six times more abundant than in Andvord Bay. Lowest abundance was on the open shelf, where the abundance was four times lower than in Andvord Bay. Among all examined specimens 98% were found in the top 4 cm of the sediment. All adult kinorhynchs were identified, and the study revealed the presence of the known Antarctic species Polacanthoderes shiraseae and at least seven species new to science: Condyloderes notios sp. nov., Polacanthoderes grzelakae sp. nov., Echinoderes ahlfeldae sp. nov., E. nataliae sp. nov., E. kathleenhannae sp. nov., E. antarcticus sp. nov., and E. crux sp. nov. In addition to the five new species of Echinoderes, two potentially known species are reported. Echinoderes aff. angustus shows close resemblance to the Arctic E. angustus, and the specimens only differed by their lack of a midventral fissure in segment 2, present in Arctic specimens of E. angustus only. A detailed examination of the E. angustus type material revealed new diagnostic details for the species, i.e., a complete mapping of sensory spots, presence of a middorsal protuberance between segments 10 and 11, and a tergal division of segment 11. Another unidentified species, Echinoderes aff. beringiensis/romanoi/xalkutaat, showed such close resemblance to three congeners that further studies are needed to identify clear diagnostic characters for the species, or alternatively clarify whether they should be synonymised. The comparisons prompted by the two unidentified species led to the suggestion of a new species group, the Echinoderes remanei species group, including E. remanei, E. angustus, E. beringiensis, E. cernunnos, E. drogoni, E. galadrielae, E. obtuspinosus, E. quasae, E. pennaki, E. romanoi, and E. xalkutaat. In addition, the Echinoderes aragorni species group is proposed, including the New Zealand species E. aragorni and the new species E. crux.
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RBINS Staff Publications 2025
