Ecological traits affect the seasonal migration patterns of breeding birds along a subtropical altitudinal gradient

Altitudinal bird migration involves seasonal shifts up and down the altitude gradient annually.Asia as the place with the largest number of altitudinal migrants,has quite few related studies,especially for montane and temperate avifaunas.To explore the potential drivers of seasonal altitudinal migration for birds in the middle of Hengduan Mountains,we conducted a three-year investigation on breeding and non-breeding season bird communities at eight elevational bands(1200–4200 m)in the Gongga Mountains.We examined the altitudinal migration patterns and relationships between seasonal distribution shifts and species'traits of 50 species with sufficient data recorded in both seasons.We found that a large proportion of breeding birds underwent altitudinal migration and showed three migration patterns(downslope shift,upslope shift,no shift).Seasonal distribution shifts were mainly correlated with certain ecological traits.Species breeding at high and mid-elevations,nesting in scrub and being omnivorous are more likely to show downslope movements during the non-breeding season.In addition,territorially weaker species exhibited more diverse migration patterns.Notably,we found the hand-wing index(HWI)was actually more convincing than body mass in explaining altitudinal migration.These results consolidate the studies of seasonal altitudinal migration in montane birds.Our study could be used to bridge existing knowledge gaps that currently impeding effective conservation for montane avifaunas in the Hengduan Mountains.

A quantitative approach to monitoring new sand cay migration in Nansha Islands

Sand cay is a special kind of islet formed by coral detritus and bioclast, which is common in Nansha Islands of China. Some sand cays play an important role in ocean strategy and economy, but surprisingly we know little about them, especially those recently formed sand cays. In this research, we monitor migration of a new sand cay in Nanxun Jiao（Gaven Reef） using a series of Quick Bird and World View-2 satellite images between June 2006 and August 2013. We conduct a regression between migration distance and wind observational data to examine the migration patterns of the new sand cay. The migration distance is calculated based on the sand cay locations extracted based on Normalized Difference Water Index（NDWI）. The wind observational data downloaded from NOAA are reformed into four wind direction vectors. Based on the results of regression, we concluded that the migration of the new sand cay on Nanxun Jiao was significantly associated with the east, west and north wind.East wind was the main influence factor of the migration; its impact strength was almost twice as the west and north wind. The south wind has little effect on the migration of the sand cay, which is partly blocked by the artificial structure in the south.

Environmental risk assessment of industrial byproduct gypsum utilized for flling abandoned mines

In response to the basic policy of green and low-carbon circular development to solve resource,environmental and ecological problems,gypsum is considered to be a flling material for mine backflling.To explore the potential risks of gypsum to the groundwater environment due to the backflling of abandoned mines,a sequential batch leaching experiment was carried out in this paper,which used three types of industrial waste gypsum,namely,phosphorus gypsum(PG),titanium gypsum(TG)and fue gas desulfurization gypsum(FGDG).COMSOL Multiphysics 5.4 software was used to simulate and solve the migration process of the leached metal elements in the mine foor when these three gypsum types were used as flling materials to observe the concentration distributions and difusion distances of the metal elements from these three gypsum types in the mine foor.The results show that(1)during repeated contact of the three types of industrial waste gypsum with the leaching medium,the pH levels changed,and the changes in pH afected the leaching patterns for the heavy metal elements in the gypsum.(2)Based on the concentrations of the metal elements that were leached from the three types of gypsum,it can be determined that these three types of gypsum are not classifed as hazardous solid wastes,but they cannot be ruled out with regard to their risk to the groundwater environment when they are used as mine flling materials.(3)When the three types of gypsum are used as flling materials,the concentration distributions of the metal elements and their migration distances all exhibit signifcant changes over time.The concentration distributions,difusion rates and migration distances of the metal elements from the diferent gypsum types are afected by their initial concentrations in the leachate.The maximum migration distances of Zn in the foor from the PG,FGDG and TG are 8.2,8.1 and 7.5 m,respectively.

Trajectory modeling revealed a southwest-northeast migration corridor for fall armyworm Spodoptera frugiperda(Lepidoptera:Noctuidae)emerging from the North China Plain

The fall armyworm Spodoptera frugiperda,an invasive insect pest native to the Americas,has established populations throughout eastern China.The North China Plain一a key corn-producing area in East China with a unique topography一was invaded by fall armyworm in 2019 and is seriously threatened by this migratory pest.However,the spatiotemporal extent of the migratory movements of fall armyworm from the North China Plain remains poorly understood.Using an air transport-based trajectory modeling approach that incorporates flight behavior,we simulated the potential nocturnal migration trajectories of fall armyworm from the North China Plain based on historical meteorological data from June to October of 2015-2019,and examined the night-time atmospheric conditions associated with their possible flights.The emigration patterns showed monthly variation in the main landing area and common migration direction.The displacement of newly emerged moths from the North China Plain was concentrated in the Northeast China Plain(including Liaoning,Jilin and Heilongjiang provinces)before late summer,after which they were most likely to undertake return flights to the south(especially into Hubei,Anhui and Hunan provinces).This southwest-northeast aerial migration corridor follows the topography of East China and is affected by the East Asian monsoon.These topographic-atmospheric conditions have resulted in the North China Plain becoming a key stopover for fall armyworm populations engaging in multigenerational long-distance migration across East China.These findings contribute to our knowledge of fall army-worm migration and will aid in the implementation of management and control strategies against this highly migratory agricultural pest.