Effects of a freshwater canal discharge on an ovoviviparous isopod inhabiting an exposed sandy beach

2006 ◽  
Vol 57 (4) ◽  
pp. 421 ◽  
Author(s):  
Juan Pablo Lozoya ◽  
Omar Defeo
Keyword(s):  
Environmental Variables ◽  
Reproductive Output ◽  
Sandy Beach ◽  
Explanatory Variable ◽  
Abiotic Factors ◽  
Reproductive Traits ◽  
Discharge Canal ◽  
Beach Width ◽  
Spatial Trends ◽  
Slope Beach

The present study evaluates the effects of an artificial freshwater discharge (Canal Andreoni) on the ecology of the ovoviviparous isopod Excirolana armata. Bimonthly, 17 environmental variables plus isopod abundance, biomass, fecundity, growth and mortality were compared between three sites: ‘Barra del Chuy’ (undisturbed), at 13 km from the canal, ‘Coronilla’ (moderately disturbed), at 1 km, and ‘Andreoni’ (grossly disturbed), at the canal mouth. Environmental (salinity, slope, beach width, and swash width) and some biological (isopod abundance, biomass and growth rates) variables significantly decreased towards Canal Andreoni. Salinity was the most important explanatory variable of spatial trends in isopod biomass. However, the reproductive output, fecundity, survival and individual weight were not affected, suggesting that E. armata is regulated by density-dependent and abiotic factors operating together: the former were more intense on undisturbed conditions, whereas the latter prevailed in impacted ones. Internal brooding counteracts the effect of fresh water, which explains the lack of effect of environmental harshness on reproductive traits.

Reproductive output of ponderosa pine in response to thinning and prescribed burning in western Montana

2008 ◽  
Vol 38 (4) ◽  
pp. 844-850 ◽  
Author(s):  
Gregory Peters ◽  
Anna Sala
Keyword(s):  
Pinus Ponderosa ◽  
Prescribed Fire ◽  
Ponderosa Pine ◽  
Reproductive Output ◽  
Management Practices ◽  
Prescribed Burning ◽  
Seed Mass ◽  
Reproductive Traits ◽  
Western Montana ◽  
Cone Production

Thinning and thinning followed by prescribed fire are common management practices intended to restore historic conditions in low-elevation ponderosa pine ( Pinus ponderosa Dougl. ex P. & C. Laws.) forests of the northern Rocky Mountains. While these treatments generally ameliorate the physiology and growth of residual trees, treatment-specific effects on reproductive output are not known. We examined reproductive output of second-growth ponderosa pine in western Montana 9 years after the application of four treatments: thinning, thinning followed by spring prescribed fire, thinning followed by fall prescribed fire, and unthinned control stands. Field and greenhouse observations indicated that reproductive traits vary depending on the specific management treatment. Cone production was significantly higher in trees from all actively managed stands relative to control trees. Trees subjected to prescribed fire produced cones with higher numbers of filled seeds than trees in unburned treatments. Seed mass, percentage germination, and seedling biomass were significantly lower for seeds from trees in spring burn treatments relative to all others and were generally higher in trees from fall burn treatments. We show for the first time that thinning and prescribed-burning treatments can influence reproductive output in ponderosa pine.

scholarly journals Spatial-temporal analysis of the diet of a non-native fish in the Santa Cruz Reservoir, Brazilian semi-arid

2018 ◽  
Vol 30 (0) ◽  
Author(s):  
Jônnata Fernandes de Oliveira ◽  
Jean Carlos Dantas de Oliveira ◽  
José Luís Costa Novaes ◽  
Antonia Elissandra Freire de Souza ◽  
Marla Melise Oliveira de Sousa ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Abiotic Factors ◽  
Temporal Analysis ◽  
Arid Environment ◽  
Temporal Variations ◽  
Environmental Data ◽  
Animal Origin ◽  
Santa Cruz ◽  
Main Item ◽  
Semi Arid

Abstract Aim The diet of Plagioscion squamosissimus present in the Santa Cruz Reservoir, Rio Grande do Norte, Brazil, was investigated, evaluating the influences of spatial and temporal variations and abiotic factors in the utilization of food resources. Methods The samplings were performed quarterly between February 2011 and November 2014. Of the 525 specimens captured, 375 presented food items in the stomachs. The diet was determined using: (i) Feeding Index (IAi); (ii) and the graphical interpretation of the food strategy through non-metric multidimensional scaling (NMDS) analyzes, the differences in diet being tested from Permutational Multivariate Analyzes of Variance (PERMANOVA). To verify if environmental variables influence the Canonical Correspondence Analyzes (CCA) were used, using the data from the IAi the environmental data, being the significance of the axes tested through Monte Carlo simulations. Results The species feed mainly on items of animal origin, vegetable being a resource ingested accidentally. The diet was composed of shrimp, fish, insect, mollusk and vegetable, the latter rarely found. The shrimp was the main item (92.57%) and the insects (7.24%) accessory items. Spatial and temporal ordering demonstrated that the species didn’t present variation in diet composition, as well as a low association between diet and environmental variables. Conclusion P. squamosissimus is characterized as carcinophagous, due to the predominance of shrimp in its diet, evidencing that the species is adapted to the conditions offered by the Brazilian semi-arid environment.

scholarly journals Are Reproductive Traits Related to Pollen Limitation in Plants? A Case Study from a Central European Meadow

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 640
Author(s):  
Michael Bartoš ◽  
Štěpán Janeček ◽  
Petra Janečková ◽  
Eliška Chmelová ◽  
Robert Tropek ◽  
...  
Keyword(s):  
Pollen Limitation ◽  
Abiotic Factors ◽  
Pollen Grains ◽  
Reproductive Traits ◽  
Biodiversity Loss ◽  
Plant Reproduction ◽  
Landscape Fragmentation ◽  
Global Changes ◽  
A Site ◽  
Relationship Of

The deficiency of pollen grains for ovule fertilization can be the main factor limiting plant reproduction and fitness. Because of the ongoing global changes, such as biodiversity loss and landscape fragmentation, a better knowledge of the prevalence and predictability of pollen limitation is challenging within current ecological research. In our study we used pollen supplementation to evaluate pollen limitation (at the level of seed number and weight) in 22 plant species growing in a wet semi-natural meadow. We investigated the correlation between the pollen limitation index (PL) and floral traits associated with plant reproduction or pollinator foraging behavior. We recorded significant pollen limitation for approximately 41% of species (9 out of 22 surveyed). Seven species had a significant positive response in seed production and two species increased in seed weight after pollen supplementation. Considering traits, PL significantly decreased with the number of pollinator functional groups. The relationship of PL with other examined traits was not supported by our results. The causes of pollen limitation may vary among species with regard to (1) different reproductive strategies and life history, and/or (2) temporary changes in influence of biotic and abiotic factors at a site.

scholarly journals The reproductive performance of the Red-Algae shrimp Leander paulensis (Ortmann, 1897) (Decapoda, Palaemonidae) and the effect of post-spawning female weight gain on weight-dependent parameters

2015 ◽  
Vol 63 (3) ◽  
pp. 207-216 ◽  
Author(s):  
Uwe Zimmermann ◽  
Fabrício Lopes Carvalho ◽  
Fernando L. Mantelatto
Keyword(s):  
Weight Gain ◽  
Egg Production ◽  
Reproductive Output ◽  
Coastal Region ◽  
Reproductive Traits ◽  
Development Stage ◽  
Female Size ◽  
Egg Volume ◽  
Average Fecundity ◽  
Female Weight

AbstractDecapod species have evolved with a variety of reproductive strategies. In this study reproductive features of the palaemonid shrimp Leander paulensiswere investigated. Individuals were collected in the coastal region of Ubatuba, São Paulo, Brazil. In all, 46 ovigerous females were examined in terms of the following reproductive traits: fecundity, reproductive output, brood loss and egg volume. Leander paulensis produces a large number of small eggs with an average fecundity of 635 ± 246 eggs. Egg volume increased significantly from early (0.034 ± 0.008 mm3) to late development stage (0.05 ± 0.012 mm3). The reproductive output did not correlate with female size. The weight of females bearing stage 2 eggs was significantly higher than that of females carrying stage 1 eggs. We assume that the reason for this weight gain is the recovery of female reserves that have been depleted for egg production. Moreover, we emphasize that this weight gain must be considered when evaluating weight-dependent variables such as reproductive output or brood loss in relation to female weight. Otherwise, an overestimation of these variables might lead to inaccurate results.

scholarly journals Reproductive traits of the gray ratsnake Ptyas korros from three geographically distinct populations

2012 ◽  
Vol 58 (6) ◽  
pp. 820-827 ◽  
Author(s):  
Long-Hui Lin ◽  
Fei Mao ◽  
Ce Chen ◽  
Xiang Ji
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Reproductive Output ◽  
Reproductive Traits ◽  
Egg Laying ◽  
Laying Date ◽  
Egg Mass ◽  
Size Number ◽  
Female Reproductive Traits ◽  
Clutch Mass

Abstract We collected gravid gray rat snakes Ptyas korros from three geographically distinct populations in China, Chenzhou (CZ), Jiangshan (JS) and Dinghai (DH), to study geographical variation in female reproductive traits. Egg-laying dates differed among the three populations such that at the most northern latitude egg-laying was latest, and earliest at the most southern lati-tutde. Clutch size, clutch mass, egg mass, egg shape, within clutch variability in egg sizes and relative clutch mass differed among the three populations, whereas post-oviposition body mass did not. Except for egg-laying date, none of the traits examined varied in a geographically continuous trend. CZ and DH females, although separated by a distance of approximately 1100 km as the crow flies, were similar in nearly all traits examined. JS females were distinguished from CZ and DH females by their higher fecundity (clutch size), greater reproductive output (clutch mass) and more rounded eggs. Our data do not validate the prediction that larger offspring should be produced in colder localities. The absence of an egg size-number trade-off in each of the three populations presumably suggests that P. korros is among species where eggs are well optimized for size within a population.

Dietary Variation in a Freshwater Fish Species: Relative Contributions of Biotic Interactions, Abiotic Factors, and Spatial Structure

1994 ◽  
Vol 51 (12) ◽  
pp. 2856-2865 ◽  
Author(s):  
Pierre Magnan ◽  
Marco A. Rodríguez ◽  
Pierre Legendre ◽  
Sylvain Lacasse
Keyword(s):  
Spatial Structure ◽  
Freshwater Fish ◽  
Fish Species ◽  
Environmental Variables ◽  
Brook Trout ◽  
Diet Composition ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Relative Contribution ◽  
Dietary Variation

We used multivariate analyses to examine which variables among the environmental and spatial components can best account for dietary variation in a freshwater fish, brook trout, Salvelinus fontinalis. The diet composition of brook trout was quantified in 37 lakes of the Laurentian Shield, Québec, Canada. Among the 25 measured environmental variables, fish species composition, sampling date, macrophyte abundance, and trout body length were the best predictors of diet composition. The total variation in diet composition was partitioned into four components: pure environmental 21.6%, pure spatial 23.2%, shared 19.9%, and unexplained 35.3%. A significant spatial trend in diet composition existed even after accounting for the main effects measured by the environmental variables. The two sets of spatial variables, when combined with the environmental descriptors, extracted different components of the dietary variation. The study allowed us to (1) highlight the role of spatial structure in diet variation of brook trout, (2) determine the relative contribution of both environmental and spatial components, and (3) generate testable hypotheses concerning mechanisms underlying the observed structure. Dependent variables other than diet composition, such as the density of different species at different sampling sites, can be used within the same statistical framework in studies of community ecology.

scholarly journals Rising temperatures increased recruitment of brown tiger prawn (Penaeus esculentus) in Moreton Bay (Australia)

2016 ◽  
Vol 74 (3) ◽  
pp. 741-749 ◽  
Author(s):  
Marco Kienzle ◽  
David J. Sterling
Keyword(s):  
Environmental Variables ◽  
East Coast ◽  
Abiotic Factors ◽  
Fish Populations ◽  
Tropical Species ◽  
Fishing Industry ◽  
Southern Limit ◽  
Moreton Bay ◽  
Tiger Prawn ◽  
Stock Recruitment

Abiotic factors are fundamental drivers of the dynamics of wild marine fish populations. Identifying and quantifying their influence on species targeted by the fishing industry is difficult and very important for managing fisheries in a changing climate. Using multiple regression, we investigated the influence of both temperature and rainfall on the variability of recruitment of a tropical species, the brown tiger prawn (Penaeus esculentus), in Moreton Bay which is located near the southern limit of its distribution on the east coast of Australia. A step-wise selection between 60 environmental variables identified temperature as the most important environmental factor to explain the variations of recruitment between 1990 and 2014. Including temperature into the Beverton and Holt stock–recruitment relationship explained 69% of the recruitment variability compared with 9.5% when omitted. This analysis indicates that increasing temperatures have increased recruitment of brown tiger prawn in Moreton Bay.

scholarly journals Relative clutch mass of Basiliscus vittatus Wiegmann, 1828 (Squamata, Corytophanidae): female morphological constraints

Herpetozoa ◽  
2019 ◽  
Vol 32 ◽  
pp. 211-219
Author(s):  
Gabriel Suárez-Varón ◽  
Orlando Suárez-Rodríguez ◽  
Gisela Granados-González ◽  
Maricela Villagrán-Santa Cruz ◽  
Kevin M. Gribbins ◽  
...  
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Abiotic Factors ◽  
Reproductive Traits ◽  
The Family ◽  
In Captivity ◽  
Abiotic And Biotic Factors ◽  
Gravid Females ◽  
Favorable Conditions ◽  
Clutch Mass

Clutch size (CS) and relative clutch mass (RCM) are considered important features in life history descriptions of species within Squamata. Variations in these two characteristics are caused by both biotic and abiotic factors. The present study provides the first account related to CS and RCM ofBasiliscus vittatusin Mexico within a population that inhabits an open riverbed juxtapositioned to tropical rainforest habitat in Catemaco, Veracruz, Mexico (170 m a.s.l.). Twenty-nine gravid females were collected and kept in captivity under favorable conditions that promote oviposition. The CS within this population was 6.2 ± 0.2 and was correlated positively with snout vent-length (SVL); while the RCM was 0.17 ± 0.006 and was correlated positively with both CS and width of egg. Factors, such as female morphology and environmental conditions, should influence these reproductive traits inB. vittatus. The data collected in this study could provide a framework for comparisons of the life history traits across populations ofB. vittatusin Mexico and within other species of the family Corytophanidae and provide a model for testing how abiotic and biotic factors may influence the CS and RCM in basilisk lizards throughout their range.

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