Plant phenology is one of the key regulators of ecosystem processes, which are sensitive to environmental change. The acceleration of urbanization in recent years has produced substantial impacts on vegetation phenology over urban areas, such as the local warming induced by the urban heat island effect. However, quantitative contributions of the difference of land surface temperature (LST) between urban and rural (ΔLST) and other factors to the difference of spring phenology (i.e., the start of growing season, SOS) between urban and rural (ΔSOS) were rarely reported. Therefore, the objective of this study is to explore impacts of urbanization on SOS and distinguish corresponding contributions. Using Hangzhou, a typical subtropical metropolis, as the study area, vegetation index-based phenology data (MCD12Q2 and MYD13Q1 EVI) and land surface temperature data (MYD11A2 LST) from 2006–2018 were adopted to analyze the urban–rural gradient in phenology characteristics through buffers. Furthermore, we exploratively quantified the contributions of the ΔLST to the ΔSOS based on a temperature contribution separation model. We found that there was a negative coupling between SOS and LST in over 90% of the vegetated areas in Hangzhou. At the sample-point scale, SOS was weakly, but significantly, negatively correlated with LST at the daytime (R2 = 0.2 and p < 0.01 in rural; R2 = 0.14 and p < 0.05 in urban) rather than that at nighttime. Besides, the ΔSOS dominated by the ΔLST contributed more than 70% of the total ΔSOS. We hope this study could help to deepen the understanding of responses of urban ecosystem to intensive human activities.
Varied environmental conditions in coastal-inland zones tend to influence soil faunal communities. However, few studies have focused on the responses of soil fauna to environmental variations along the coastal-inland gradient. In order to better understand the aforementioned responses, a total of 80 soil macro-faunal samples were collected at the five different distances from the coastline of China’s Bohai Bay. The results revealed that the compositions, structural characteristics and diversity of the soil macro-fauna varied among the different habitats. With the increases in the distance from the sea, the individual density, richness and diversity levels of the soil macro-fauna all first increased and then decreased. The individual density, richness and diversity values were all at their maximum at 30 km from the sea. The Edge effect promoted unique and rare soil macro-faunal taxa. Formicidae, Curculionidae and Aphodiidae were found to be the edge taxa. Agelenidae, Liocranidae and Nematocera were considered to be indicator taxa of severe sea effects. Paradoxosomatidae was an indicator taxon of slight effects. Overall, the environmental variations along the coastal-inland gradient were found to have the potential to affect the soil macro-faunal communities, and the different taxa of the soil macro-fauna responded to those variations in different ways. This study further revealed the processes and mechanisms of the sea influencing the soil macro-faunal communities, which had been caused by the coastal-inland gradient. The results of this study also provided a theoretical basis for developing future biodiversity guidelines for coastal ecosystems.
The harsh environmental conditions in alpine tundra exert a significant influence on soil macro-arthropod communities, yet few studies have been performed regarding the effects of vegetation heterogeneity on these communities. In order to better understand this question, a total of 96 soil macro-arthropod samples were collected from four habitats in the Changbai Mountains in China, namely, the Vaccinium uliginosum habitat, Sanguisorba sitchensis habitat, Rhododendron aureum habitat, and Deyeuxia angustifolia habitat. The results revealed that the taxonomic composition of the soil macro-arthropods varied among the habitats, and that dissimilarities existed in these communities. The abundance, richness and diversity in the D. angustifolia habitat were all at their maximum during the sampling period. The vegetation heterogeneity affected the different taxa of the soil macro-arthropods at various levels. In addition, the vegetation heterogeneity had direct effects not only on soil macro-arthropod communities, but also indirectly impacted the abundance, richness and diversity by altering the soil fertility and soil texture. Overall, our results provide experimental evidence that vegetation heterogeneity can promote the abundance, richness and diversity of soil macro-arthropods, yet the responses of soil macro-arthropods to vegetation heterogeneity differed among their taxa.
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