Long-Term Trends in Ringed Sawback (Graptemys oculifera) Growth, Survivorship, Sex Ratios, and Population Sizes in the Pearl River, Mississippi

2017 ◽  
Vol 16 (2) ◽  
pp. 215-228 ◽  
Author(s):  
Robert L. Jones
Keyword(s):  
Sex Ratios ◽  
Pearl River ◽  
Population Sizes ◽  
Long Term Trends ◽  
The Pearl River

scholarly journals Long-term trends and drought: spatiotemporal variation in juvenile sex ratios of North American ducks

2021 ◽  
Author(s):  
Sage Ellis ◽  
Madeleine Lohman ◽  
James Sedinger ◽  
Perry Williams ◽  
Thomas Riecke
Keyword(s):  
United States ◽  
North American ◽  
Sex Ratios ◽  
Survival Rates ◽  
The United States ◽  
Avian Communities ◽  
Eastern United States ◽  
Bird Populations ◽  
Long Term Trends

Sex ratios affect population dynamics and individual fitness, and changing sex ratios can be indicative of shifts in sex-specific survival at different life stages. While climate- and landscape-change alter sex ratios of wild bird populations, long-term, landscape scale assessments of sex ratios are rare. Further, little work has been done to understand changes in sex ratios in avian communities. In this manuscript, we analyse long-term (1961-2015) data on five species of ducks across five broad climatic regions of the United States to estimate the effects of drought and long-term trends on the proportion of juvenile females captured at banding. As waterfowl have a 1:1 sex ratio at hatch, we interpret changes in sex ratios of captured juveniles as changes in sex-specific survival rates during early life. Seven of twelve species-region pairs exhibited evidence for long-term trends in the proportion of juvenile females at banding. The proportion of juvenile females at banding increased for duck populations in the western United States and typically declined for duck populations in the eastern United States. We only observed evidence for an effect of drought in two of the twelve species-region pairs, where the proportion of females declined during drought. As changes to North American landscapes and climate continue and intensify, we expect continued changes in sex-specific juvenile survival rates. More broadly, we encourage further research examining the mechanisms underlying long-term trends in juvenile sex ratios in avian communities.

scholarly journals Quantile Analysis of Long-Term Trends of Near-Surface Chlorophyll-a in the Pearl River Plume

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1662 ◽  
Author(s):  
Na Gao ◽  
Yi Ma ◽  
Mingli Zhao ◽  
Li Zhang ◽  
Haigang Zhan ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Northern South China Sea ◽  
Coastal Region ◽  
River Plume ◽  
Pearl River ◽  
Near Surface ◽  
High Quantiles ◽  
Quantile Regression Analysis ◽  
The Pearl River

The concentration of chlorophyll-a (CHL) is an important proxy for the amount of phytoplankton biomass in the ocean. Characterizing the variability of CHL in the Pearl River Plume (PRP) is therefore of great importance for the understanding of the changes in oceanic productivity in the coastal region. By applying quantile regression analysis on 21-year (1998–2018) near-surface CHL data from satellite observations, this study investigated the long-term trend of CHL in the PRP. The results show decreasing trends (at an order of 10−2 mg m−3 year−1) for all percentiles of the CHL in the PRP, suggesting a decrease in productivity in the past two decades. The trends differ fundamentally from those in the open regions of the northern South China Sea with mixed signs and small magnitudes (10−4 mg m−3 year−1). The magnitudes of the trends in high quantiles (>80th) are larger than those in low quantiles (<50th) in the PRP, indicative of a decrease in the variance of the CHL. The area with apparent decreasing trends is restricted to the PRP in summer and extends to the entire coastal region in winter. This decrease in CHL is possibly attributed to the decrease in nutrient input from the river runoff and the weakening of wind-forced mixing rather than the changes in sea surface temperature. This study extends our knowledge on the variability of CHL in the PRP and provides references to the investigation of the changes of the coastal ecological environment.

Long-term trend of visibility and its characterizations in the Pearl River Delta (PRD) region, China

2008 ◽  
Vol 42 (7) ◽  
pp. 1424-1435 ◽  
Author(s):  
Xuejiao Deng ◽  
Xuexi Tie ◽  
Dui Wu ◽  
Xiuji Zhou ◽  
Xueyan Bi ◽  
...  
Keyword(s):  
Pearl River Delta ◽  
River Delta ◽  
Pearl River ◽  
Term Trend ◽  
The Pearl River Delta ◽  
The Pearl River ◽  
Long Term Trend

Long-term change in tidal dynamics and its cause in the Pearl River Delta, China

Geomorphology ◽  
2010 ◽  
Vol 120 (3-4) ◽  
pp. 209-223 ◽  
Author(s):  
Wei Zhang ◽  
Xiaohong Ruan ◽  
Jinhai Zheng ◽  
Yuliang Zhu ◽  
Hongxu Wu
Keyword(s):  
Pearl River Delta ◽  
River Delta ◽  
Pearl River ◽  
Tidal Dynamics ◽  
The Pearl River Delta ◽  
Term Change ◽  
The Pearl River
Sign in / Sign up

Export Citation Format

Share Document