Ecological Research最新文献

Cultivated tropical grasslands have been hypothesized to have great soil carbon (C) and nutrient storage potential. However, global change and the resulting seasonal soil drying–wetting shifts may affect this potential. Limited data exist to predict the biogeochemical responses of these ecosystems under different management and climate conditions. Our objectives were (1) to explore the relationship between total and available C, nitrogen (N), and phosphorus (P), microbial biomass C, and C and N transformation in surface soil during the dry season under the two livestock species influence (water buffaloes [WB]; and Nellore cattle [NC]) and (2) to explore the livestock species effect on soil C transformation patterns across time and during a water pulse in the dry season. The results suggest that there is a seasonal pattern response and a differentiation in soil microbial activity shaped by livestock type and soil wetting. Furthermore, a high potential net C mineralization rate (PNCMR) (20.03 ± 1.13 μg C g⁻¹ d⁻¹) and retention of ammonium (0.04 ± 0.005 mg g⁻¹), nitrate (0.04 ± 0.005 mg g⁻¹), and soluble P (12.51 ± 0.9 μg g⁻¹) appear to be associated with the ecosystem with WB. In the case of NC, a lower PNCMR (9.54 ± 0.60 μg C g⁻¹ d⁻¹) and high N mineralization (84.34 ± 12.35 μg g⁻¹) may promote N losses in dry soil. These results could help to better understand the conservation and soil nutrient availability of complex grazing ecosystems in the subhumid tropics.

Currently, rapid socioeconomic development has caused over-exploitation of mountain land, severely damaging the regional ecology. Rational development and ecological protection provide a scientific basis for precise land use planning, management, and restoration. This study focuses on Shiqian County, a typical mountainous area, using land data from 2005 to 2020 and employing land use models, ecological quality indices, and spatial autocorrelation to reveal spatiotemporal differences in land use-ecology interactions and explore internal mechanisms. The results show that, from 2005 to 2020, changes in rural residential land and other construction land were the most significant, followed by changes in urban construction land. During 2010–2015, 5.199 km² of cultivated land was converted to other construction land. From 2015 to 2020, 7.104 km² of forest land was converted to water area. The overall ecological environment of Shiqian County shows a deteriorating trend, mainly due to the conversion of cultivated land, forest land, and meadow to construction land, which has the highest contribution rates of 16.803%, 28.273%, and 13.60%, respectively. Between 2005 and 2020, the ecological environment quality was mainly dominated by “high-high” agglomeration areas, with a significant p-value of 0.001–0.05. Over time, the ecological environment has been affected by many factors, among which NDVI has the strongest impact. Thus, relevant government departments urgently need to implement policies for the precise adjustment of land use structure, optimize land use and planting patterns, and provide a decision-making basis for precise land use planning and ecological restoration.

Plant and soil microbial communities are crucial in regulating various ecosystem functions. However, the specific effects of aboveground plant communities versus belowground microbial communities (e.g., protozoa, bacteria, and fungi) and their interactions on ecosystem multifunctionality (EMF) mediated by slope positions remain largely unknown. Here, we investigated the relationship between EMF and biodiversity indices on the upper, middle, and lower slopes of subalpine meadows on the Qinghai-Tibet Plateau and how changes in plant and soil biodiversity and other abiotic factors mediate EMF. The results showed that plant diversity (species, function, phylogeny) and soil microbial diversity (bacteria, ciliates) were significantly higher on the downslope site than on the upper slope site, and EMF was significantly higher with decreasing slope position. Phylogenetic diversity and ciliate diversity were the dimensions of plant and soil biodiversity, respectively, that contributed most to EMF, suggesting the critical role of ecological niche complementarity and protozoan-driven nutrient cycling in maintaining multifunctionality. Slope position alters the relationship between biodiversity and EMF by regulating resource allocation: soil biodiversity dominates EMF when relative slope position (RSP, i.e., the ratio of the relative elevation of the watershed) is <0.30; the role of plant diversity is enhanced when RSP is >0.34. Generally speaking, our study provides valuable insights into the critical role of multi-trophic biodiversity in conserving ecosystem multifunctionality in subalpine grassland communities, as well as strong support for the importance of biodiversity conservation.

Paved roads (PRs), a key feature of urbanization, adversely affect ecosystem processes, including seed dispersal. PRs can influence the ecological functions of urban forests because of their proximity to trees and forest fragments. Therefore, understanding the effects of two critical factors, canopy cover and proximity to a forest patch, on fecal deposition on PRs is essential for assessing the impact on animal-mediated seed dispersal. In this study, we quantified fecal deposition on PRs and analyzed the effects of canopy cover and distance from forest fragments on this deposition. We also estimated the potential seed loss resulting from fecal deposition on the PRs in urban forest fragments of Yokohama, Japan. In total, 1976 fecal samples were collected from the PRs. More of these samples were observed on PRs near forest patches (n = 1671) than on PRs distant from forest patches (n = 305). The canopy cover significantly influenced fecal deposition on PRs. Numerous bird fecal samples on the PRs were expected to contain at least one seed. In addition, approximately 949 seeds could be deposited in the feces of the birds. This study indicates that PRs are critical factors contributing to seed dispersal disservice within urban ecosystems. Urban forest management practices should also consider mitigating the impact of PRs on species interactions and the services they provide.

The expansion of whole genome sequencing from single individuals per species to range-wide sampling of diversity now allows for nuanced investigation of the phylogeography of introgression. Analyses by Kishida et al. (2022) show gene flow between Alaskan American black bears (Ursus americanus) and both Korean and Japanese populations of Asian black bears (U. thibetanus). Further, they show no gene flow between Asian black and brown bears. Fundamental to these results was the use of four taxon D-statistics, which placed the polar bear (U. maritimus) as the outgroup species. As polar bears are not an outgroup to any of the focal species tested, this violated a main assumption of the D-statistic test. Thus, a new analysis of the phylogeography of introgression of Asian black, American black, and brown bears was undertaken, but with the divergent Andean bear (Tremarctos ornatus) serving as outgroup. I did not identify introgression between Asian black bear populations and intra-specific lineages of brown or American black bears. However, an ancient signature of introgression between Asian black and brown bears was observed and affected all intra-specific lineages of both species. Expanded aDNA resources for these species would aid in explaining the phylogeography of introgression and potential for adaptive introgression among bears.

In the tropical forests of Southeast Asia, the dipterocarp species stands out as the most significant tree group in terms of ecosystem stability and forestry management. Shorea macrophylla, found on Borneo Island, is particularly noteworthy for its rapid growth, high oil content nut production, and versatile timber characteristics, making it a prime candidate for plantation material in rehabilitating degraded forests. We collected population samples of S. macrophylla in Kalimantan Island and evaluated parameters such as genetic diversity, genetic structure, and estimated divergence times of the populations using SSR (simple sequence repeat) markers and SNPs (single-nucleotide polymorphisms). Interestingly, the estimated divergence time of genetic groups was similar between the two markers, with SNP markers likely offering a more accurate estimation owing to their higher marker count. Although SNP markers generally offer advantages over SSR markers in genetic studies, the latter remains valuable for assessing genetic diversity due to its high polymorphism. We conclude that SSR markers are still useful for identifying hotspot areas in terms of genetic diversity. Our study revealed that both DNA markers identified the Northeast Kalimantan population as the most genetically distinct population of S. macrophylla, which is important for the conservation of this species. By using multiple DNA markers with different characteristics, the history and features of the population can be more clearly explored. The result of species distribution modeling suggests that the habitat of this species may expand on Kalimantan Island due to future global warming.

To conserve wetland biodiversity, conservation plans must consider both local environmental factors and catchment-scale factors that influence groundwater cycles. Spring-dependent animals are particularly sensitive to groundwater conditions, and land-use changes associated with urbanization can affect factors such as the temperature and stability of groundwater supply. This study aimed to examine how catchment-scale land use influences the distribution patterns of a spring-dependent animal. To explore this, we constructed a generalized linear model (GLM) incorporating both indirect influences from catchment land use and direct effects from local wetland environmental factors. Furthermore, to provide an example of conservation planning that considers land use, we assessed habitat suitability at the wetland level using a GLM and at the grid level using maximum entropy modeling (MaxEnt) with only landscape variables. Distribution data of Lefua echigonia, an indicator species of spring-dependent animals, were collected through field surveys and environmental DNA analyses in 102 first-order valleys of the Lake Inba watershed. The GLM results indicated that an index of spring water stability, the percentage of permeable surfaces in the catchment, precipitation, the period of rice paddy abandonment in the valley bottom, and valley length (representing habitat size) positively influenced the fish's presence, while summer temperature had a negative effect. The MaxEnt analysis also showed a positive effect of the percentage of permeable surfaces. Our results highlight that both land use within a catchment and catchment size, which can affect the volume and stability of spring water, are important factors for conserving suitable habitats for spring-dependent animals.

Continental plastic production is on the rise, making these materials significant pollutants with a growing recognition of their impact on agricultural environments. The aim of this study was to provide information about the abundance of plastics in an agricultural environment around the town of Sagunto (Valencia, eastern Spain) and on the use of plastics by the great tit (Parus major), a breeding species in these agricultural areas. Environmental plastic samples were collected using the quadrat method, applied randomly across the study area. Sixty-four samples were collected. Data on the great tit were collected from 35 successful nests, which were gathered after the chicks had fledged. Our results show that 65.6% of the environmental samples contain plastics. From the abundance per square meter, we estimated a density of 18,750 plastic pieces per hectare at the studied agricultural ecosystem. Among the 19 nests containing plastics (54.3%), 556 plastic pieces were found, with the number of pieces per nest ranging from 1 to 153 (mean = 12 ± 1.28; N = 35). Furthermore, the presence of a nearby landfill in Sagunto showed no correlation with the abundance of plastics in either the environment or the nests. This suggests that plastic abundance depends on very local sources, which in this case might be the consequence of farmers and laborers not removing the plastics after use. The great tit selects filament plastics and the colors black and red to incorporate into their nests.

The relationship between organism size and abundance, or population density, has been well characterized by a scaling relationship, with different studies reporting a range of scaling exponents. Various mechanistic explanations have been put forth, more recently leveraging metabolic scaling, but there is still considerable debate about the value of exponents. In this paper, I take a phenomenological approach and use dimensional analysis to address the determinants of organism abundance. By considering four variables—energy input, body size, length, and time—a scaling law for organism abundance as a function of body size emerges, most parsimoniously with an exponent of −1. I also consider how abundance is likely to scale with variables with dimensions of length and time: velocity, acceleration, variance, and covariance. Different scaling exponents for the abundance–body size scaling relationship, including −3/4, can easily be obtained by considering life history components or interactions with the abiotic environment.

Community ecologists often consider their research approaches as either process-oriented or pattern-oriented, which has frequently sparked controversy over the superiority or inferiority of each approach. Here, we argue the ambiguity in the distinction between pattern- and process-oriented approaches by reviewing previous studies. We then highlight three factors—interest, methods, and significance—that influence researchers' perceptions and evaluation of research approaches. This examination reveals the subjectivity inherent in classifying studies. Furthermore, we emphasize the complementary nature of pattern- and process-oriented perspectives in understanding ecological communities. We advocate a scientific culture that embraces diverse research approaches and acknowledges the various levels of generality required to address complex ecological issues. Ultimately, fostering an environment where ecologists with diverse approaches and perspectives collaborate constructively, rather than compete antagonistically, is essential for advancing community ecology.