Distribution of crabs along a habitat gradient on the Yellow Sea coast after Spartina alterniflora invasion

Abstract

The effects of Spartina alterniflora invasion on macrobenthos have long been of concern; however, there is currently no unified conclusion regarding these effects. Most studies on crabs focus on one species or limited habitat types, and assessments of the community-level effects of S. alterniflora invasion considering multiple species and habitat types have rarely been conducted. In this study, we sampled crabs along a habitat gradient from the shoreline to inland areas on the Yellow Sea coast, including the mudflat, S. alterniflora marsh, Suaeda salsa marsh and Phragmites australis marsh. A total of 10 crab species were found among all habitats, with five species in the mudflat, six species in S. alterniflora marsh, seven species in S. salsa marsh and four species in P. australis marsh. The Shannon index values for the crab communities were similar between S. alterniflora marsh and S. salsa marsh, and these values were significantly higher than those for the mudflat and P. australis marsh. However, the total biomass of crabs was highest in the mudflat, and Metaplax longipes, Philyra pisum and Macrophthalmus dilatatus exclusively preferred the mudflat. The analysis of principal components and similarities showed that the crab community structure in S. alterniflora marsh was most similar to that in S. salsa marsh, while the crab community structure in the mudflat was most different from that in the other habitat types. Our results demonstrate that the distribution of crabs varies across a habitat gradient after S. alterniflora invasion and that the crab community in S. alterniflora marsh is slightly different from that associated with the local vegetation but shows a large difference from that in the mudflat. This study indicates that some crab species may have adapted to habitat containing alien S. alterniflora, while other crab species reject this new marsh type. The effects of the distribution of crabs after S. alterniflora invasion on the regional ecosystem need further study in the future.

Red-crowned crane (Grus japonensis) prefers postharvest reed beds during winter period in Yancheng National Nature Reserve

“…Five random quadrats of one m × one m with 20 cm deep were dug up and removed from within each plot (Jia et al, 2013). To sample crabs in these plots, pitfall trap was deployed in each quadrat by burying cylindrical plastic buckets (20 cm in diameter, 30 cm deep) at the soil surface (Chen et al, 2019). The crabs in each trap were checked in the next day.…”

Song variation of a native songbird in a modified habitat by invasive plant

“…Historically, the vegetation of the reserve mainly consisted of common reed and Suaeda salsa. After smooth cordgrass invaded, its area began to steadily expand, rapidly replacing native plants, and forming a band of monoculture vegetation along the shoreline (Chen et al 2019), and resulting in a gradual decline in the native habitat of birds. At present, there are stable breeding populations of plain prinia in both native reed and invasive smooth cordgrass habitats (Fig.…”

“…This made it possible for us to explore the song differences of plain prinia between native and invaded habitats. Native reeds have a greater plant height, while smooth cordgrass has a greater stem density and softer stems (Chen et al 2019), resulting in 2 completely different habitat vegetation structures. The invasion areas of smooth cordgrass are closer to the coast, while the native reeds grow at relatively higher elevations, which leads to differences in microclimate, for example, wind speed, and then may affect the energetic cost of bird singing (Ward & Slater 2005).…”