Buoyancy affects stranding rate and dispersal distance of floating litter entering the sea from river mouths

2021 ◽  
Vol 173 ◽  
pp. 113028
Author(s):  
Kyle Maclean ◽  
Eleanor A. Weideman ◽  
Vonica Perold ◽  
Peter G. Ryan
2019 ◽  
Vol 59 (6) ◽  
pp. 1089-1092
Author(s):  
I. V. Miskevich ◽  
A. V. Leshchev ◽  
D. S. Moseev ◽  
A. S. Lokhov

In the winter low water season in March and the first week of April 2019, complex hydrological and hydrochemical studies were carried out at the mouths of two small rivers of the White Sea catchment basin (the Mudyuga river, which flows into the Dvina Bay, and the Tamitsa river, which flows into the Onega Bay). The results indicate significant differences in the short-period variability of hydrological and hydrochemical parameters in the winter in the studied river mouths compared with the characteristics observed in the tidal estuaries of large and medium rivers, as well as in the mouths of small rivers of the southern seas.


2008 ◽  
Vol 43 (3) ◽  
pp. 409-419 ◽  
Author(s):  
Norio Arakaki ◽  
Atsushi Nagayama ◽  
Aya Kobayashi ◽  
Kazuhiko Tarora ◽  
Mitsunobu Kishita ◽  
...  

Author(s):  
Eduardo de Freitas Costa ◽  
Silvana Schneider ◽  
Giulia Bagatini Carlotto ◽  
Tainá Cabalheiro ◽  
Mauro Ribeiro de Oliveira Júnior

AbstractThe dynamics of the wild boar population has become a pressing issue not only for ecological purposes, but also for agricultural and livestock production. The data related to the wild boar dispersal distance can have a complex structure, including excess of zeros and right-censored observations, thus being challenging for modeling. In this sense, we propose two different zero-inflated-right-censored regression models, assuming Weibull and gamma distributions. First, we present the construction of the likelihood function, and then, we apply both models to simulated datasets, demonstrating that both regression models behave well. The simulation results point to the consistency and asymptotic unbiasedness of the developed methods. Afterwards, we adjusted both models to a simulated dataset of wild boar dispersal, including excess of zeros, right-censored observations, and two covariates: age and sex. We showed that the models were useful to extract inferences about the wild boar dispersal, correctly describing the data mimicking a situation where males disperse more than females, and age has a positive effect on the dispersal of the wild boars. These results are useful to overcome some limitations regarding inferences in zero-inflated-right-censored datasets, especially concerning the wild boar’s population. Users will be provided with an R function to run the proposed models.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Florentine Riquet ◽  
Christiane-Arnilda De Kuyper ◽  
Cécile Fauvelot ◽  
Laura Airoldi ◽  
Serge Planes ◽  
...  

AbstractCystoseira sensu lato (Class Phaeophyceae, Order Fucales, Family Sargassaceae) forests play a central role in marine Mediterranean ecosystems. Over the last decades, Cystoseira s.l. suffered from a severe loss as a result of multiple anthropogenic stressors. In particular, Gongolaria barbata has faced multiple human-induced threats, and, despite its ecological importance in structuring rocky communities and hosting a large number of species, the natural recovery of G. barbata depleted populations is uncertain. Here, we used nine microsatellite loci specifically developed for G. barbata to assess the genetic diversity of this species and its genetic connectivity among fifteen sites located in the Ionian, the Adriatic and the Black Seas. In line with strong and significant heterozygosity deficiencies across loci, likely explained by Wahlund effect, high genetic structure was observed among the three seas (ENA corrected FST = 0.355, IC = [0.283, 0.440]), with an estimated dispersal distance per generation smaller than 600 m, both in the Adriatic and Black Sea. This strong genetic structure likely results from restricted gene flow driven by geographic distances and limited dispersal abilities, along with genetic drift within isolated populations. The presence of genetically disconnected populations at small spatial scales (< 10 km) has important implications for the identification of relevant conservation and management measures for G. barbata: each population should be considered as separated evolutionary units with dedicated conservation efforts.


Oryx ◽  
2002 ◽  
Vol 36 (3) ◽  
pp. 266-271 ◽  
Author(s):  
Juan Carlos Serio-Silva ◽  
Victor Rico-Gray

We studied changes in germination rates and dispersal distance of seeds of Ficus perforata and F. lundelli dispersed by howler monkeys (Alouatta palliata mexicana), in a small (40 ha) ‘disturbed’ and a larger (>600 ha) ‘preserved’ tropical rainforest in southern Veracruz, Mexico. The interaction between A. p. mexicana and Ficus (Urostigma) spp. is beneficial for the interacting species and has important implications for their conservation. Howler monkeys gain from the ingestion of an important food source, germination rates of Ficus seeds are improved by passage through the monkeys' digestive tract, and the seeds are more likely to be deposited in a site suitable for germination and development. Seed dispersal distances are relatively larger in the preserved site, with both the size of the forest area and the spatial pattern of Ficus affecting the dispersal process. In a large forest fragment with ‘regularly’ distributed Ficus individuals the howler monkeys move away from the seed source, increasing the probability that the seeds are desposited on a tree other than Ficus, which is important for the germination and future development of a hemiepiphytic species. In a small forest fragment with trees distributed in clumps howlers repeatedly use the same individual trees, and faeces containing seeds may be dropped on unsuitable trees more often. These are key issues when addressing conservation policies for fragmented forests.


1993 ◽  
Vol 19 (3) ◽  
pp. 399-446 ◽  
Author(s):  
J.P.M. Syvrrski ◽  
J.M. Alcott
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document