Description of three new species of Aposphragisma Thoma, 2014 (Araneae: Oonopidae) from Sumatra, Indonesia

Three species from the family Oonopidae are newly described from leaf litter habitats in Sumatra, Indonesia based on male and female morphology. All three species belong to the genus Aposphragisma Thoma, 2014: Aposphragisma globosum sp. n., Aposphragisma jambi sp. n., and Aposphragisma sumatra sp. n

Description of four new species of armoured spiders (Araneae, Tetrablemmidae) from Sumatra, Indonesia

Four new species of armoured spiders from Sumatra, Indonesia are described. Three species are described in the genus Ablemma Roewer, 1963 and one species in the genus Brignoliella Shear, 1978; Ablemma andriana sp. n. (male), Ablemma contrita sp. n. (male and female), Ablemma kelinci sp. n. (male) and Brignoliella patmae sp. n. (male and female). The female of Ablemma singalang Lehtinen, 1981 is described here for the first time. The first record of Brignoliella for Sumatra is also presented

Reducing Fertilizer and Avoiding Herbicides in Oil Palm Plantations—Ecological and Economic Valuations

Oil palm plantations are intensively managed agricultural systems that increasingly dominate certain tropical regions. Oil palm monocultures have been criticized because of their reduced biodiversity compared to the forests they historically replaced, and because of their negative impact on soils, water, and climate. We experimentally test whether less intensive management schemes may enhance biodiversity and lessen detrimental effects on the environment while maintaining high yields. We compare reduced vs. conventional fertilization, as well as mechanical vs. chemical weed control (with herbicides) in a long-term, full-factorial, multidisciplinary experiment. We conducted the experiment in an oil palm company estate in Sumatra, Indonesia, and report the results of the first 2 years. We measured soil nutrients and functions, surveyed above- and below-ground organisms, tracked oil palm condition and productivity, and calculated plantation gross margins. Plants, aboveground arthropods, and belowground animals were positively affected by mechanical vs. chemical weed control, but we could not detect effects on birds and bats. There were no detectable negative effects of reduced fertilization or mechanical weeding on oil palm yields, fine roots, or leaf area index. Also, we could not detect detrimental effects of the reduced fertilization and mechanical weeding on soil nutrients and functions (mineral nitrogen, bulk density, and litter decomposition), but water infiltration and base saturation tended to be higher under mechanical weeding, while soil moisture, and microbial biomass varied with treatment. Economic performance, measured as gross margins, was higher under reduced fertilization. There might be a delayed response of oil palm to the different management schemes applied, so results of future years may confirm whether this is a sustainable management strategy. Nevertheless, the initial effects of the experiment are encouraging to consider less intensive management practices as economically and ecologically viable options for oil palm plantations

Conifers and non-native tree species shift trophic niches of generalist arthropod predators in Central European beech forests

Abstract Background Functional diversity is vital for forest ecosystem resilience in times of climate-induced forest diebacks. Admixing drought resistant non-native Douglas fir, as a partial replacement of climate-sensitive Norway spruce, to native beech forests in Europe appears promising for forest management, but possible consequences for associated biota and ecosystem functioning are poorly understood. To better link forest management and functional diversity of associated biota, we investigated the trophic niches (∆13C, ∆15N) of epigeic generalist predators (spiders and ground beetles) in mixed and pure stands of European beech, Norway spruce and non-native Douglas fir in north-west Germany. We assessed the multidimensional niche structure of arthropod predator communities using community-based isotopic metrics. Results Whilst arthropod ∆13C differed most between beech (high ∆13C) and coniferous stands (low ∆13C), ∆15N was lowest in non-native Douglas fir. Tree mixtures mitigated these effects. Further, conifers increased isotopic ranges and isotopic richness, which is linked to higher canopy openness and herb complexity. Isotopic divergence of ground beetles decreased with Douglas fir presence, and isotopic evenness of spiders in Douglas fir stands was lower in loamy sites with higher precipitation than in sandy, drier sites. Conclusions We conclude that tree species and particularly non-native trees alter the trophic niche structure of generalist arthropod predators. Resource use and feeding niche breadth in non-native Douglas fir and native spruce differed significantly from native beech, with more decomposer-fueled and narrower feeding niches in beech stands (∆13C, isotopic ranges and richness). Arthropod predators in non-native Douglas fir, however, had shorter (∆15N) and simplified (isotopic divergence) food chains compared to native forest stands; especially under beneficial abiotic conditions (isotopic evenness). These findings indicate potential adverse effects of Douglas fir on functional diversity of generalist arthropod predators. As tree mixtures mitigated differences between beech and conifers, mixed stands including (non-native) conifers constitute a promising compromise between economic and conservational interests

Isotopic data and relative biomasses of ground-dwelling generalist predators in pure and mixed stands of European beech, Norway spruce and non-native Douglas fir

The dataset contains calibrated isotopic data (∆13C, ∆15N) and relative biomasses of spiders and ground beetles, sampled in 2019 in Lower Saxony, Germany, within the RTG 2300 project "Enrichment of European beech forests with conifers". Arthropods were sampled with pitfall traps and identified to species level by Kriegel et al (2021) and Matevski and Schuldt (2023). Natural abundance isotopic ratios (δ13C, δ15N) were determined by the Centre for Stable Isotope Research Analysis at the University of Göttingen and thereafter calibrated with leaf litter isotopic ratios. Calibrated isotopic values (∆) were used to calculate multidimenional isotopic metrics, which were compared between different stand types and regions. The stand types were Douglas fir, beech-Douglas fir, beech, beech-spruce and spruce