Ecological Effects of Roads on the Plant Diversity of Coastal Wetland in the Yellow River Delta

Abstract

The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of β T and Jaccard's coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0–20 m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing β-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20 m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion.

Widespread sampling biases in herbaria revealed from large‐scale digitization

“…Because roads are known to alter local environmental conditions and facilitate biological invasions (e.g. Forman & Alexander, ; Hui et al ., ; Griffith et al ., ; Li et al ., ) and botanists and herbaria predominate in cities, specimens collected in proximity to either are unlikely to represent a random sample across species distributions. Specifically, species collected along roadsides are likely to be overrepresented by species that thrive with disturbance, and underrepresented by forest interior and wetland species that are harmed by disturbance (Gutzwiller & Flather, ; Rivers‐Moore & Cowden, ).…”

Widespread sampling biases in herbaria revealed from large-scale digitization

“…As routes became established, they formed our modern infrastructure, including roads, railroads, and cities that contain herbaria, and spatial biases associated with infrastructure likely increased (Everill et al, 2014). Because roads are known to fragment populations and landscapes ( e.g., Forman & Alexander, 1998; Hui et al , 2003; Griffith et al , 2010; Li et al ., 2014) and botanists and herbaria predominate in cities, specimens collected in proximity to either are unlikely to represent a random sample across species distributions. Species collected along roadsides are likely to be over-represented by species that thrive with disturbance, and under-represented by forest interior and wetland species.…”

Distribution of carbon, nitrogen and phosphorus in coastal wetland soil related land use in the Modern Yellow River Delta

“…There were significant negative relations of soil salinity and TOC and TN in study region, while the significant relation of nutrients and pH was not observed (Table 2). The soil salinity not only was a key factor which decided natural vegetation distribution in coastal wetlands252835, but also increased rates of net N and P mineralization fluxes and turnover in tidal wetland soils55, resulting in alteration of the soil nutrient content and distribution. Previous study showed that there were significant positive relations between soil salinity and TOC and TN ( p  < 0.05) in new-born wetland of the YRD1318.…”

“…Since it is in the sensitive areas to land-ocean interaction, a large number of wetland is formed because of rapid sediment accumulation from land runoff at estuary. Currently, there are series ecological problems of uncontrolled land reclamation, road and dam construction, river dry-up, pollution, sea level rise and coastal erosion2425, leading to the coastal wetlands decline seriously and the ecosystems degraded gradually26. Most of land use is changed from natural wetlands to farm land, saltern-culture pone which close related human being activities13.…”