Ecological Research最新文献

Manganese (Mn) hyperaccumulator plants are rare in nature but provide important insights into plant–soil interactions, Mn nutritional physiology, and biogeochemical cycling. X-ray fluorescence (XRF) herbarium analysis of Japanese wild plants was used to investigate Mn concentrations in 25 different Ilex species (totaling 619 specimens). Among the 25 analyzed Ilex species, nine species had leaves containing > 10,000 mg kg⁻¹ Mn (dry weight), and in six of these species, multiple hyperaccumulator-level specimens were found, representing 8%–21% of the specimens within those six species. Analysis of Mn and six other essential elements (K, Ca, P, S, Fe, and Zn) revealed that Ilex had, on average, four times higher Zn concentrations than those in most other plants, with a significant positive correlation between Mn and Zn. No other elements showed significant correlations with Mn. In contrast to other Mn hyperaccumulators, including Chengiopanax sciadophylloides from Japan, no positive Mn–Ca correlation was observed. These findings identify Ilex as the second Mn hyperaccumulator group reported from Japan and show that, like C. sciadophylloides, hyperaccumulation in Ilex was achieved under ordinary forest soils without known contamination sources (noncontaminated soil). The distinct accumulation pattern observed here in the genus Ilex suggests a physiological mechanism different from the Mn-Ca co-accumulation observed in other Mn hyperaccumulators.

The resource budget hypothesis is widely accepted as a physiological explanation of masting, which is characterized by highly variable, synchronous reproduction within a population across years. According to the hypothesis, when resources are depleted by a large reproductive output, it takes more than one year to replenish them. This results in intermittent mass flowering and seed production. The key resources depleted by a single reproduction have been identified in several woody species but rarely in herbaceous species. We examined the adequacy of the resource budget hypothesis for masting in the herbaceous species Veratrum album subsp. oxysepalum and identified the key resources. Over an 11-year period, we investigated stem volume as an indicator of resource storage level and flowering in 61 individuals, each consisting of a single ramet, tagged in the 2013 mast year in a population in northern Japan. We compared the concentrations and masses of carbon and nitrogen in the aboveground and belowground parts of flowering and non-flowering ramets. Stem volume decreased in the year after reproduction and gradually recovered in subsequent years. Flowering occurred again once the ramet had grown to a large size. These results support the predictions of the resource budget hypothesis. Flowering ramets had greater concentrations and masses of carbon in their aboveground parts than non-flowering ramets, but smaller concentrations and masses in their belowground parts. Conversely, there were no consistent differences in nitrogen concentration or mass between flowering and non-flowering ramets. Therefore, carbon is the key limiting factor in reproduction for this species.

Subterranean ecosystems are characterized by environmental stability and low availability of trophic resources, both of which are key factors shaping invertebrate communities. Although interest in subterranean biodiversity has increased in recent years, the influence of environmental variables across multiple spatial scales remains poorly understood. In this study, we evaluated the role of microhabitat characteristics in determining species richness, community composition, and taxonomic distinctness of terrestrial invertebrates in 16 limestone caves in the Serra da Bodoquena, Mato Grosso do Sul, Brazil. Sampling was conducted at two spatial scales: 39 mesoscale plots (3 × 10 m) and 117 microscale plots (1 × 1 m), and complemented by non-systematic general collections targeting troglobitic species. In total, 445 species belonging to 27 orders were recorded. Twenty species displayed traits associated with cave life. We found that trophic resource diversity and distance from the cave entrance influenced species richness, with resource heterogeneity promoting richness while increasing distance reduced it. At the meso-scale, community composition was primarily determined by small variations in temperature, indicating that even minimal differences in a thermally stable environment can act as important ecological filters for the distribution of subterranean species. At the micro-scale, shelter availability was the main factor associated with community composition, highlighting the role of substrate physical structure in providing refuges and microclimates that support different species. Taxonomic distinctness showed a positive correlation with species richness, indicating that richer communities sustain greater evolutionary diversity. In light of anthropogenic pressures, our findings provide a scientific basis for guiding conservation strategies.

Developing cost-effective monitoring tools that cover a broad range of taxonomic groups is urgently needed to implement effective conservation strategies. One promising approach involves collecting genetic samples from hematophagous, sarcophagous, or coprophagous invertebrates, followed by amplification and sequencing of residual vertebrate DNA to reveal vertebrate diversity. In invertebrate-derived DNA (iDNA) monitoring, species-specific life histories, physiological traits, and behavioral characteristics introduce distinct biases, depending on the invertebrate taxon used. In this study, we assessed terrestrial vertebrate diversity by simultaneously employing iDNA derived from leeches and flies, together with camera trapping, in a species-poor temperate forest ecosystem in Yakushima, Japan. Our aim was to evaluate the detection biases of each method and to identify optimal combinations of monitoring tools. We detected a greater number of vertebrate species using fly-derived iDNA (15 species) than using leech-derived iDNA (5 species). Fly-derived iDNA detected mammals, birds, reptiles, and amphibians, whereas leech-derived iDNA detected only mammals and amphibians. This difference was partly due to the greater ease of collecting flies compared with leeches, which resulted in different sample sizes. However, even when accounting for sample size, fly-derived iDNA captured a broader range of species. Camera trapping detected a comparable number of mammal species to fly-derived iDNA but provided lower taxonomic resolution. Notably, we detected all non-volant terrestrial mammal species known to inhabit in this ecosystem of low species diversity by combining fly-derived iDNA with camera trapping. However, these methods were less effective in detecting avian and reptilian diversity.