scholarly journals Influence of roadkill during breeding migration on the sex ratio of land crab (Sesarma haematoche)

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Mi Ryu ◽  
Jae Geun Kim
Keyword(s):  
Sex Ratio ◽  
Population Decline ◽  
High Tide ◽  
Coastal Areas ◽  
Road Mortality ◽  
Artificial Structures ◽  
Land Crab ◽  
Land Crabs ◽  
Breeding Migration ◽  
Island Habitats

Abstract Adult land crabs generally live on land while their larvae live in the sea. In the case of Sesarma haematoche, female crabs migrate from land to sea to release the larvae at the high tide of syzygy night. Artificial structures along coastal areas are being obstacles for the migration of land crabs and causing synchronized roadkills on coastal roads during breeding migration. In this research, we compared the sex ratios of crab populations in coastal areas with coastal roads and uninhabited island areas with no road. The proportion of females in inland habitats with coastal roads was significantly smaller than island habitats. In particular, females are exposed to the risk of annually repeated roadkills, and the proportion of females decreases rapidly with their growth. If this tendency is general for land crab populations in the coastal areas with roads, significant road mortality of female land crabs during breeding migration can lead to severe population decline in coastal areas. Therefore, it is necessary to take an action to save land crabs crossing coastal roads.

scholarly journals Coastal road mortality of land crab during spawning migration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mi Ryu ◽  
Jae Geun Kim
Keyword(s):  
Population Decline ◽  
Spring Tide ◽  
Residential Area ◽  
Spawning Migration ◽  
Vehicular Traffic ◽  
Road Mortality ◽  
Coastal Forest ◽  
Land Crab ◽  
Land Crabs ◽  
Ocean Sprawl

AbstractLand crabs are threatened by ocean sprawl even though they act as keystone consumers in coastal forest. Female land crabs must migrate to the sea annually to release larvae. However, they face the risk of road mortality which reduces ecological connectivity. We investigated the spawning migration rhythm and the roadkill of land crab. Migrating crabs and roadkilled crabs were recorded on coastal roads in South Korea from July 28 to August 27 in 2018. Female land crabs mainly released zoeae during spring tide. The number of roadkilled crabs also synchronized with migration peak. A majority (95%) of 739 roadkilled carcasses were female crabs. As a result, the female crabs accounted only 29.6% of the population which can lead to a population decline. The roadkill density was the highest in a residential area without cement guardrails. These results suggest the mitigation actions for land crab roadkill. Among them, prohibiting vehicular traffic between sunset and midnight during spring tides in the breeding season should increase the viability of the population.

scholarly journals The role of anthropogenic disturbance and invasion of yellow crazy ant in a recent decline of land crab population

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ching-Chen Lee ◽  
Ming-Chung Chiu ◽  
Chun-Han Shih ◽  
Chin-Cheng Scotty Yang ◽  
Hung-Chang Liu ◽  
...  
Keyword(s):  
Anthropogenic Disturbance ◽  
Natural Habitat ◽  
Additive Model ◽  
Land Crab ◽  
Land Crabs ◽  
Breeding Migration ◽  
Survey Results ◽  
Natural Spring ◽  
Study Sites

AbstractThe yellow crazy ant, Anoplolepis gracilipes was first reported in Kenting National Park, Taiwan, in the 2000s, raising the concern of this invasive ant’s potential effects on the native land crab populations. We investigated the distribution and abundance of A. gracilipes and its adverse effect on the land crab populations at four land crab hotspots within the park. Our survey results indicated that A. gracilipes was widespread and abundant at three of the study sites (Hsiangchiaowan, Shadao, and Natural Spring), while the distribution was much more confined at the fourth site (Houwan). Land crab populations experienced a notable decline at all the study sites except Houwan, indicating an inverse relationship between the population of land crabs and distribution/abundance of A. gracilipes. Combining the results of visual observations, the decline of land crab populations can be attributed, at least partially, to direct attacks by A. gracilipes on land crabs in their natural habitat and during the breeding migration season. Generalized additive model showed that worker abundance of this ant is associated with human disturbance levels, suggesting that anthropogenic disturbance may have contributed to the decline in land crab populations via promoting the abundance of A. gracilipes.

11. Mitigation of Wildlife Collision Mortality at Little Cataraqui Creek Wetland

2018 ◽  
Author(s):  
Erin Keenan ◽  
Jeffy Henderson ◽  
Lauren Malo ◽  
Diana Pedersen
Keyword(s):  
Coastal Wetland ◽  
Public Awareness ◽  
Population Decline ◽  
Urban Traffic ◽  
Coastal Marsh ◽  
Road Mortality ◽  
Wetland Ecosystems ◽  
Turtle Species ◽  
Wetland Species ◽  
Specific Species

               Our research team is concerned with potential reptile and amphibian road mortality through Little Cataraqui Creek wetland along Front Rd. and Bath Rd. in Kingston, Ontario. The coastal marsh is a provincially significant wetland that supports species of migrating and breeding waterfowl, wetland dependent reptiles and amphibians, and may support some of Ontario’s threatened turtle species. The coastal wetland also provides a protected nesting area for a migrating species within Lake Ontario. Specific species of turtles, salamanders and frogs will be investigated.  Our team will identify general breeding, nesting and migratory behavior patterns of associated wetland species, and establish potential indirect effects on the wetland ecosystem due to population decline. Traffic volume and speed limits of Front Rd. and Bath Rd. at Little Cataraqui Creek Wetland will be identified, and any current wildlife crossing systems in place will be evaluated. Based on this research, our team will establish the significance of wildlife road mortality within Little Cataraqui Creek Wetland at Front Rd. and Bath Rd., and propose suitable mitigation techniques. These techniques may include implementing structural design solutions such as road barriers, culverts, etc., as well as increasing public awareness of wildlife crossing on Bath Rd. and Front Rd. by proposing appropriate traffic laws in the area. Themes include wetland species breeding and nesting behavior, and urban/traffic development issues surrounding wetland ecosystems.

scholarly journals Sea Oats, Uniola paniculata

EDIS ◽  
2018 ◽  
Vol 2018 (5) ◽  
Author(s):  
Debbie Miller ◽  
Mack Thetford ◽  
Chris Verlinde ◽  
Gabriel Campbell ◽  
Ashlynn Smith
Keyword(s):  
Wind Waves ◽  
High Tide ◽  
Coastal Areas ◽  
Salt Tolerant ◽  
Uniola Paniculata ◽  
Vertical Growth ◽  
Sea Oats ◽  
In The Wild ◽  
Florida Panhandle ◽  
High Tide Line

Sea oats occur throughout Florida on beach dunes and beaches and on coastal areas west to Texas and north to Maryland. Sea oats are vital dune builders that accumulate sand and prevent erosion due to wind, waves, and large storms. As sand is trapped by the long leaves of sea oats, vertical growth is stimulated, and rooting occurs at the buried nodes. This plant is extremely drought- and salt-tolerant, grows up to the high tide line of beaches, and propagates both vegetatively and by seed in the wild (Shadow 2007).https://edis.ifas.ufl.edu/sg186 This publication is derived from information in SGEB-75/SG156, Dune Restoration and Enhancement for the Florida Panhandle, by Debbie Miller, Mack Thetford, Christina Verlinde, Gabriel Campbell, and Ashlynn Smith. https://edis.ifas.ufl.edu/sg156.

scholarly journals Analysis of Coastal Zone Data of Northern Yantai Collected by Remote Sensing from 1990 to 2018

2019 ◽  
Vol 9 (20) ◽  
pp. 4466 ◽  
Author(s):  
Min Zhou ◽  
Mengquan Wu ◽  
Guangzong Zhang ◽  
Lianjie Zhao ◽  
Xiaoyun Hou ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Coastal Zone ◽  
High Tide ◽  
Coastal Areas ◽  
Visual Interpretation ◽  
Point Change ◽  
Continuous Increase ◽  
Change Rate ◽  
Ecological Resources ◽  
Bare Land

Using remote sensing images of different time phases from 1990 to 2018, the surface coverage information of northern Yantai (coastline, 2 km from coastline to land) was extracted by means of average high tide line and visual interpretation. The end point change rate (EPR) and linear regression rate were used to study the coastline change rate, the fractal dimension of the coastline in the study area was analyzed, and the change of the type of coastal surface cover was analyzed by the transition matrix. The results show that: (1) Form 1990 to 2018, a significant trend of a continuous increase in the total length of coastline was observed with an increase of 181.08 km (43.18%). In the study area, the coastline of Laizhou had the greatest change rate with an EPR value of 33.67 m/a, whereas the coastline of Laishan had the smallest change rate with an EPR value of 0.30 m/a. (2) Over the past 30 years, with the rapid economic development of Yantai and the ensuant urbanization, the total surface area of the coastal zone in the study area has increased by 144.94 km2, mainly in the areas covered by structures and forests/grasses, by 112.96 km2 and 96.08 km2, respectively, while the areas of desert/bare land and water have decreased by 92.26 km2 and 12.32 km2, respectively. (3) The changes among different types in the study area were clear, mainly from desert/bare land, cultivated land, and building areas to forests/grasses cover and structures. The change areas were mainly concentrated in Laizhou, Longkou, Zhifu, and Penglai. Frequent human activities are an important factor affecting the continuous expansion of the coastal areas of Jiaodong Peninsula to the sea. Aquaculture, coastal construction, construction of artificial islands, and expansion of port terminals have seriously affected the sustainability of ecological resources in the coastal areas. At the same time, the changes in the ecological environment in the coastal zone will have a greater impact on the health of the coastal zone.

Variation in maternal attendance patterns and pup behaviour in a declining population of Steller sea lions (Eumetopias jubatus)

1997 ◽  
Vol 75 (8) ◽  
pp. 1241-1246 ◽  
Author(s):  
Wendy R. Hood ◽  
Kathryn A. Ono
Keyword(s):  
Prey Availability ◽  
Population Decline ◽  
High Tide ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Breeding Area ◽  
Foraging Effort ◽  
Sea Lions ◽  
Attendance Patterns ◽  
Breeding Seasons

Maternal attendance patterns of lactating female Steller sea lions (Eumetopias jubatus) and the activity budgets of pups on Año Nuevo Island, California, were compared between the 1973 and 1992 breeding seasons to investigate temporal changes in behaviour that may be associated with population decline. Females were absent from the breeding area longer in 1992, which may reflect increased foraging effort. Pups also spent significantly less time sucking and more time swimming in 1992. Suckling time is correlated with milk intake in some otariid species, thus the decreased amount of time 1992 pups spent sucking could reflect a reduction in the total volume of milk produced by females. Pups in 1992 are likely to have spent more time swimming than pups in 1973 because high tide covered a greater proportion of the study site in 1992 than in 1973. An increase in time females spent at sea and a decrease in time pups spent sucking are consistent with behavioural changes associated with reduced prey availability.

scholarly journals Analysis of the dynamics of coastal landform change based on the integration of remote sensing and gis techniques: Implications for tidal flooding impact in pekalongan, central java, Indonesia

2019 ◽  
Vol 38 (3) ◽  
pp. 17-29 ◽  
Author(s):  
Fajar Yulianto ◽  
Suwarsono ◽  
Taufik Maulana ◽  
Muhammad Rokhis Khomarudin
Keyword(s):  
Remote Sensing ◽  
Land Surface ◽  
High Tide ◽  
Coastal Areas ◽  
Change Analysis ◽  
Tidal Flooding ◽  
Gis Techniques ◽  
Coastal Landforms ◽  
Coastal Landform ◽  
The Impact

Abstract Coastal landforms are located in the interface zone between atmosphere, ocean and land surface systems formed by the geomorphic process of erosion, depositional, and subsidence. Studying the dynamics of coastal landform change is important for tracing the relationship between coastal landform changes and tidal flooding in the coastal areas of Pekalongan, Indonesia. The method of integrating remote sensing data with geographic information system (GIS) techniques has been widely used to monitor and analyze the dynamics of morphology change in coastal landform areas. The purpose of this study is to map the dynamics of landform change in the study area from 1978 to 2017 and to analyze its implications for the impact of tidal flooding. The results of the mapping and change analysis associated with coastal landforms can be classified into four landform types: beach, beach ridge, backswamp and alluvial plain. Changes in coastal morphology and landform topography affected by land subsidence and changes in land use/ land cover have contributed to the occurrence of tidal flooding in the study area. Beach ridges perform an important role as natural levees which hold back and prevent the entry of seawater at high tide in coastal areas. A limitation of this study is that, as it focuses only on the physical aspects of coastal landform characteristics for one of the factors causing tidal flooding.

scholarly journals Research progress and prospect of coastal flood disaster risk assessment against global climate change

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Jiayi Fang ◽  
Peijun Shi
Keyword(s):  
Climate Change ◽  
Risk Assessment ◽  
Global Climate Change ◽  
Global Climate ◽  
High Tide ◽  
Coastal Flooding ◽  
Coastal Areas ◽  
Mitigation Measures ◽  
Research Progress ◽  
Coastal Flood

The sea level rise under global climate change and coastal floods caused by extreme sea levels due to the high tide levels and storm surges have huge impacts on coastal society, economy, and natural environment. It has drawn great attention from global scientific researchers. This study examines the definitions and elements of coastal flooding in the general and narrow senses, and mainly focuses on the components of coastal flooding in the narrow sense. Based on the natural disaster system theory, the review systematically summarizes the progress of coastal flood research in China, and then discusses existing problems in present studies and provide future research directions with regard to this issue. It is proposed that future studies need to strengthen research on adapting to climate change in coastal areas, including studies on the risk of multi- hazards and uncertainties of hazard impacts under climate change, risk assessment of key exposure (critical infrastructure) in coastal hotspots, and cost-benefit analysis of adaptation and mitigation measures in coastal areas. Efforts to improve the resilience of coastal areas under climate change should be given more attention. The research community also should establish the mechanism of data sharing among disciplines to meet the needs of future risk assessments, so that coastal issues can be more comprehensively, systematically, and dynamically studied.

Female biased mortality caused by anthropogenic nest loss contributes to population decline and adult sex ratio of a meadow bird

2008 ◽  
Vol 141 (12) ◽  
pp. 3040-3049 ◽  
Author(s):  
Martin U. Grüebler ◽  
Heidi Schuler ◽  
Mathis Müller ◽  
Reto Spaar ◽  
Petra Horch ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Population Decline ◽  
Adult Sex Ratio ◽  
Nest Loss

The role of migration in the demographic development of the Kaliningrad oblast

2019 ◽  
pp. 73-84 ◽  
Author(s):  
A.V. Lуalina
Keyword(s):  
Population Decline ◽  
Coastal Areas ◽  
Demographic Development ◽  
Male Population ◽  
Sex Structure ◽  
Baltic Countries ◽  
Kaliningrad Region ◽  
The Baltic ◽  
The Impact ◽  
Age And Sex

The article provides an analysis of the current level of migration to and from the Kaliningrad region. The article focuses on the impact of migration on the replacement of the natural population decline and its age and sex structure. The data on the age and sex of migrants and the population of municipalities of the Kaliningrad region in 2011-2017 were used in the analysis. The author has built a typology of migration trends in the region. The main classifying feature was the criterion of migration intensity in different age and gender groups, which was estimated using the net migration rate. It was found that despite the generally favourable nature of the age profile of migration for demographic development, migration replaces the reduction in the number of the working-age population only partially. The ageing of the population is observed in the East and South-West of the region, some coastal areas, whereas the rejuvenation of the population is registered in other coastal areas and the Kaliningrad agglomeration. The gender structure of migration tends to exacerbate the existing disparities. In the municipalities of the region, the intraregional and external migration largely go in the opposite directions. Migration exchange with the CIS, the Baltic countries and regions of Russia partly replaces the loss of the male population and youth in intraregional exchange.

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