Tropical coral island vegetation poses formidable challenges, particularly in elucidating the determinants of vegetation species richness. In response, our study compared the differences in plant species biodiversity and soil physicochemical properties on seven adjacent coral islands at different stages of vegetation succession, from bare land to 100% vegetation coverage in the South China Sea, all of which were less than 0.3 km2. Contrary to the established island ecological theories, our results indicated that soil nutrients significantly govern the species diversity of tropical coral islands. However, the timing of soil development, island area, distance from larger islands, and island altitude were not significantly correlated. Cluster analysis showed that the diverse islands of Qilianyu Island (Seven Sisters) represent distinct stages of tropical coral island succession: pioneer vegetation, shrub and grass communities, and coral island forest vegetation. As island vegetation underwent succession, plant species increased from 6 to 57, and organic carbon, total nitrogen, and available phosphorus content significantly increased, accompanied by increasing salinity and decreasing pH. Our findings revealed a nested structure in the vegetation of tropical coral islands, primarily dominated by environmental filtering on a small scale, at least on Qilianyu Island. This indicates that the restoration of damaged island vegetation can begin with soil rehabilitation. We contend that improving soil nutrient conditions and development status contribute to the establishment of island vegetation, with careful consideration of interspecific combinations that expedite the restoration process on tropical coral islands. This study addresses the lack of clarity surrounding the determinants of vegetation species richness on tropical coral islands, thus providing a novel perspective grounded in soil nutrient-driven succession.

Plant-parasitic nematode research in the Middle East and North Africa (MENA) region faces significant challenges rooted in a need for proper assembly, diversity, and a unified and purpose-driven framework. This led to exacerbating their detrimental effects on crop production. This systematic review addresses the current situation and challenges that require targeted interventions to sustainably manage plant-parasitic nematodes and reduce their detrimental impact on agriculture production in the MENA region. We analyzed the nematode-related research conducted within the region over the past three decades to assess available resources and promote diverse research approaches beyond basic morphology-focused surveys. We show that crops are attacked by a diverse spectrum of plant-parasitic nematodes that exceed the global economic threshold limits. In particular, Meloidogyne species exceed the threshold limit by 8 - 14-fold, with a 100% frequency of occurrence in the collected soil samples, posing a catastrophic threat to crop production and the economy. We highlight detrimental agriculture practices in the MENA region, such as transferring soil from established fields to barren land, which enhances the dissemination of plant-parasitic nematodes, disrupting soil ecology and causing significant agricultural challenges in newly cultivated areas. Looking into the behavior of farmers, raising awareness must be accompanied by available solutions, as more practical alternatives are needed to gain the confidence of the farmers. We propose integrating microbial-based products and soil development practices in hygienic farming as resilient and sustainable solutions for nematode management. Increased emphasis is required to diversify the nematode-related research areas to bridge the gaps and facilitate the transition from fundamental knowledge to practical solutions. A cohesive network of nematologists and collaboration with national and international entities is crucial for exchanging knowledge related to legislation against invasive species.

Introduction: What were the effects of paleoanthropogenic activities on the physicochemical properties and degree of the development of soil? To search for this answer, we can not only understand the different types of ancient human activities but also explore the intensity and characteristics of the activities.Methods: In this study, soil samples from different soil layers and two profiles in the Yangshao Village cultural site in Henan Province were collected. Their physicochemical properties and the sporophyte phyllosilicates they contain were analyzed and compared.Results: We found that the paleoanthropogenic activities started in the relatively low-lying area, in which the slash-and-burn activities resulted in the soil being filled with intrusions such as charcoal debris and ceramic shards. At the same time, the coarse-grained matter was affected by the plowing activities and mostly decomposed into fine particles, and the content of clay particles reached an extreme value. The total nitrogen, phosphorus, and calcium carbonate content exceeded the average value of the natural profile, indicating that ancient humans had used human and animal feces to a certain extent to restore the fertility of arable land.Discussion: Overall, ancient human activities hindered the development of the soil, especially the ground created due to habitation activities. From the type and content of clay minerals, it could be seen that the soil in this layer has been transported from other places, has a high content of clay particles, and has experienced fire baking. It was assumed that the ground was used to cover the grain or bury the garbage and lay with clay in order to achieve the effect of sealing. As a result, the soil voids and structure had been damaged to some extent, which prevented the downward leaching or precipitation of soil particles and minerals to a certain extent, thus affecting soil development.

Permafrost soils in the northern hemisphere are known to harbor large amounts of soil organic matter (SOM). Global climate warming endangers this stable soil organic carbon (SOC) pool by triggering permafrost thaw and deepening the active layer, while at the same time progressing soil formation. But depending, e.g., on ice content or drainage, conditions in the degraded permafrost can range from water-saturated/anoxic to dry/oxic, with concomitant shifts in SOM stabilizing mechanisms. In this field study in Interior Alaska, we investigated two sites featuring degraded permafrost, one water-saturated and the other well-drained, alongside a third site with intact permafrost. Soil aggregate- and density fractions highlighted that permafrost thaw promoted macroaggregate formation, amplified by the incorporation of particulate organic matter, in topsoils of both degradation sites, thus potentially counteracting a decrease in topsoil SOC induced by the permafrost thawing. However, the subsoils were found to store notably less SOC than the intact permafrost in all fractions of both degradation sites. Our investigations revealed up to net 75% smaller SOC storage in the upper 100 cm of degraded permafrost soils as compared to the intact one, predominantly related to the subsoils, while differences between soils of wet and dry degraded landscapes were minor. This study provides evidence that the consideration of different permafrost degradation landscapes and the employment of soil fractionation techniques is a useful combination to investigate soil development and SOM stabilization processes in this sensitive ecosystem.

We assessed patterns in soil development at a recently deglaciated foreland on Anvers Island on the Antarctic Peninsula. Soil samples were collected along transects extending 35 m over bare ground from the edge of a receding glacier; the far end of these transects has been ice free for approximately 20 years. We also compared soils at the far end of these transects under bare ground to those under canopies of isolated individuals of Deschampsia antarctica, a caespitose grass, that had recently colonized the site (established for < 6 years). In addition, we compared soils at this young foreland to those in a well-developed tundra island that has been ice free for at least several hundred years. At the foreland site, soil moisture was greatest near the glacier, consistent with proximity to meltwater, and declined with distance from the glacier. This decline in soil moisture may explain the decrease in litter decomposition rates and the greater soil nitrate (NO3 (-)) concentrations that we observed with distance from the glacier. The greater soil moisture near the glacier likely promoted leaching and transport of NO3 (-) to drier soils away from the glacier. The presence of D. antarctica at the glacier foreland had little effect on soil properties, which is not surprising considering it had only colonized sampling areas during the previous 5 years. Compared to the foreland, which contained only mineral soil, soil at the older tundra site had a 2.5- to 5-cm-thick organic horizon that had much higher concentrations of total carbon, nitrogen, and NO3 (-).