Body size, not other morphological traits, characterizes cascading effects in fish assemblage composition following commercial netting

2005 ◽  
Vol 62 (12) ◽  
pp. 2802-2810 ◽  
Author(s):  
C A Layman ◽  
R B Langerhans ◽  
K O Winemiller
Keyword(s):  
Morphological Traits ◽  
Fish Assemblages ◽  
Human Impacts ◽  
Morphological Characteristics ◽  
Prey Fish ◽  
Geometric Morphometric ◽  
Complex Species ◽  
Predator Prey ◽  
Assemblage Composition ◽  
Cascading Effects

Traits used to group species and generalize predator–prey interactions can aid in constructing models to assess human impacts on food webs, especially in complex, species-rich systems. Commercial netting has reduced populations of large-bodied piscivores in some lagoons of a Venezuelan floodplain river, and cascading effects result in distinct prey fish communities in netted and unnetted lagoons. In 2002 and 2003, we sampled assemblages of prey fishes in netted and unnetted lagoons and tested whether fish size and (or) other morphological characteristics were associated with differences in assemblage composition. In both years, prey fish assemblages in netted lagoons were dominated numerically by larger species. We used geometric morphometric methods to test for a relationship between species morphological characteristics and found that neither overall morphological ordination nor specific morphological traits could be used to distinguish among assemblages. Thus, size was the only variable that was useful in explaining differences in assemblage composition. Even in this species-rich river with a complex food web, size-structured predator–prey interactions apparently influence community-level patterns and can be used to characterize human impacts.

scholarly journals Morphological correlates of prey consumed by Podarcis melisellensis (Braun, 1877) and P. siculus (Rafinesque, 1810) (Sauria, Lacertidae) from two mainland regions in the eastern Adriatic area

2013 ◽  
Vol 65 (3) ◽  
pp. 1015-1025
Author(s):  
S.Z. Stamenkovic ◽  
Rada Matic
Keyword(s):  
Resource Availability ◽  
Optimal Foraging ◽  
Morphological Traits ◽  
Prey Size ◽  
Morphological Characteristics ◽  
Optimal Foraging Theory ◽  
Variance Partitioning ◽  
Morphometric Data ◽  
Lizard Species ◽  
Trophic Resource

The correlation between trophic utilization and morphology was studied for two lizard species (Podarcis melisellensis and P. siculus) from two mainland localities in the eastern Adriatic area; this is the first report of trophic and morphometric data for P. melisellensis from mainland populations. Variance partitioning showed that most of the variation in morphological traits for the analyzed lizards was the result of differences between species, and to a lesser extent between sexes. Locality did not have a strong effect on the variation of morphological traits. Prey weight is the only characteristic of prey that generally exhibits correlations with morphological characteristics rather than prey size. The pattern of correlations is generally weaker for P. melisellensis than for P. siculus. Optimal foraging theory predictions were generally confirmed: P. siculus is more constrained by trophic resource availability, with a premium on larger and heavier prey consumed in the less productive locality (SM), which can be relaxed in more productive regions (KL). P. melisellensis shows such constraints only for males in the less productive region (SM). Females of both species consume heavier prey.

scholarly journals Cambodian Freshwater Fish Assemblage Structure and Distribution Patterns: Using a Large-Scale Monitoring Network to Understand the Dynamics and Management Implications of Species Clusters in a Global Biodiversity Hotspot

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2506
Author(s):  
Kakada Pin ◽  
Savat Nut ◽  
Zeb Hogan ◽  
Sudeep Chandra ◽  
Samadee Saray ◽  
...  
Keyword(s):  
Indicator Species ◽  
Fish Assemblage ◽  
Fish Assemblages ◽  
Mekong River ◽  
Biodiversity Hotspots ◽  
Fish Assemblage Structure ◽  
Assemblage Composition ◽  
Tonle Sap Lake ◽  
Tonle Sap ◽  
High Diversity

Mekong River Basin is one of the world’s fish biodiversity hotspots. Fisheries of the Cambodian Mekong are characterized by high diversity and productivity. However, few studies have focused on broad scale patterns and fish assemblage structure of this important system at a national level. Here, we describe spatial and seasonal variation in fish assemblages by analyzing one year of daily fish catch data sampled at 32 sites covering Cambodia’s main inland water bodies. We recorded 125 fish species. Four clusters were distinguished based on assemblage composition similarity, and 95 indicator species were identified to characterize each of the identified assemblage clusters. High diversity fish assemblages were associated with the upper Mekong system and Mekong/Bassac/Tonle Sap Rivers in Kandal Province and southern Tonle Sap Lake while lower diversity assemblages were observed in the Mekong River in Kratie and the northern area of the Tonle Sap Lake. We find significant variation in the assemblage composition between wet and dry seasons, indicating strong seasonal species turnover within clusters. Length–weight relationship analysis indicated a negative allometric growth among a majority of indicator species, reflecting suboptimal conditions for growth. Our study establishes contemporary structure and diversity patterns in the Lower Mekong River system of Cambodia, which can be used to map fish biodiversity hotspots and assess key indicative fish stocks’ statuses for conservation and management.

scholarly journals Morphological diversity of the stone crayfish − traditional and geometric morphometric approach

2019 ◽  
pp. 1 ◽  
Author(s):  
Leona Lovrenčić ◽  
Vjera Pavić ◽  
Stefan Majnarić ◽  
Lucija Abramović ◽  
Mišel Jelić ◽  
...  
Keyword(s):  
Morphological Variability ◽  
Morphological Characteristics ◽  
Morphological Diversity ◽  
Dorsal Side ◽  
Small Scale ◽  
Geometric Morphometric ◽  
Discriminant Analyses ◽  
Stone Crayfish ◽  
Multivariate Discriminant ◽  
First Time

Austropotamobius torrentium is one of four native European crayfish species inhabiting Croatian freshwaters. Existence of eight divergent monophyletic mtDNA phylogroups was described within A. torrentium; six of them are distributed in Croatia, with the highest genetic diversity established in its northern-central Dinaric region. Recent small-scale study of the stone crayfish morphological variability indicated significant differences among different phylogroups. In the present study larger sample size, covering populations from five phylogroups, was analysed with the aim of determining whether there are morphological characteristics that reliably separate stone crayfish from different phylogroups. Aiming this, 245 stone crayfish were analysed through traditional (TM) and, for the first time, geometric morphometric (GM) analyses. Multivariate discriminant analyses included 24 TM characteristics per crayfish, while GM comprised analyses of 22 landmarks on the dorsal side of cephalon. Both methods revealed congruent results, and significant differences among phylogroups in analysed features were obtained, with the cephalon shape contributing the most to crayfish discrimination. Research confirmed that both approaches, combined with statistical methods, are useful in distinguishing and separating crayfish phylogroups. Findings of present study are compatible with the previous molecular findings; stone crayfish present several distinct evolutionary lineages whose species status are currently undefined and require urgent clarification.

scholarly journals Optimal fishing samplers to reveal the morphological structure of a fish assemblage in a subtropical tidal flat

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Carolina C. Siliprandi ◽  
Víctor M. Tuset ◽  
Antoni Lombarte ◽  
Marc Farré ◽  
Carmen L. D. B. Rossi-Wongtschowski
Keyword(s):  
Tidal Flat ◽  
Fish Assemblage ◽  
Fish Assemblages ◽  
Morphological Variability ◽  
Morphological Structure ◽  
Morphological Diversity ◽  
Morphological Characters ◽  
Otter Trawl ◽  
Brazilian Coast ◽  
Geometric Morphometric

ABSTRACT Morphological characters of species are essential for assessing the functional structure of a fish assemblage, since differences between them, for example in body shape, are related to many functional and ecological traits (e.g., swimming, search for food, striking and capturing prey, evading predators, spawning). Globally, tidal flats are relevant to fish assemblages by offering feeding, refuge, and reproduction grounds. To analyze the morphofunctional structure of the fish assemblage from a tidal flat on the Brazilian coast, we conducted standardized sampling using nine different fishing gears. The geometric morphometric method was applied to describe the fish shapes and verify the morphological structure of the assemblage. Here, we present the influence/susceptibility of each gear type on the morphological diversity of the fish assemblage. The results indicated that beach seine, otter trawl, marginal encircling gillnet, and fish traps, together, were the most effective gears to represent the maximum morphological variability of fish inhabiting that tidal flat. Moreover, the assemblage showed high morphological redundancy considered as a resistance of the ecosystem for avoiding functional diversity loss, emphasizing the importance of complementary gear use when determining fish assemblages in a conservation context.

scholarly journals Morphological Assessment of Cultivated and Wild Amaranth Species Diversity

Agronomy ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 272 ◽  
Author(s):  
Ranjita Thapa ◽  
Matthew Blair
Keyword(s):  
Morphological Traits ◽  
Plant Genetic Resources ◽  
Morphological Characteristics ◽  
Germplasm Conservation ◽  
Germplasm Collection ◽  
Flower Color ◽  
Leafy Vegetables ◽  
Morphological Data ◽  
Significant Difference ◽  
Blade Shape

Amaranthus L. is genus of C4 dicotyledonous herbaceous plants comprising approximately 70 species, with three subgenera, which contains both cultivated and wild types, where cultivated ones are used for food grains, leafy vegetables, potential forages and ornamentals. Grain amaranth are pseudocereals from three species domesticated in North and South America and are notable for containing high amount of protein and minerals and balanced amino acid in their small seeds. Genetic diversity analysis of amaranths is important for development of core set of germplasm with widely diverse population and effective utilization of plant genetic resources. In this study, we evaluated a germplasm collection of 260 amaranth accessions from United State Department of Agriculture (USDA) and 33 accessions from Seed Savers’ Exchange (SSE). We evaluated morphological traits like blade pigmentation, blade shape, petiole pigmentation, branching index, flower color, stem color, inflorescence density, inflorescence shape, terminal inflorescence attitude, plant height and yield characteristics across all 293 accessions. We compared clustering within the USDA and SSE collection and across both collections. Data analysis of morphological data showed significant difference of petiole pigmentation, stem color, blade pigmentation, blade shape and flower color across different clusters of accessions of USDA unlike among different clusters of SSE where we found significant difference of only blade pigmentation, blade shape and flower color. The relationship depicted by neighbor-joining dendogram using the morphological markers was consistent with some but not all of the differences observed between species. Some divisions were found between cultivated and weedy amaranths that was substantiated by morphological characteristics but no separation of South and Central American species was observed. Substantial phenotypic plasticity limits the use of morphological analysis for phylogenetic analysis but does show that important morphological traits such as inflorescence type and plant architecture can cross species boundaries. Similarly, color variants for leaves, flowers and seeds are not exclusive to one cluster in our study nor to one species and can be used widely for breeding any of the cultigens, but not to species identification. Our findings will help in germplasm conservation of grain amaranths and facilitate in this crop’s improvement. It will also help on developing effective breeding programs involving different plant characteristics and morphological traits of Amaranths.

scholarly journals Human impacts on functional and taxonomic homogenization of plateau fish assemblages in Yunnan, China

2015 ◽  
Vol 4 ◽  
pp. 470-478 ◽  
Author(s):  
Guohuan Su ◽  
Jun Xu ◽  
Munemitsu Akasaka ◽  
Jorge García Molinos ◽  
Shin-ichiro S. Matsuzaki
Keyword(s):  
Fish Assemblages ◽  
Human Impacts

Size-dependent predator?prey relationships between pikeperch and their prey fish

2007 ◽  
Vol 16 (3) ◽  
pp. 307-314 ◽  
Author(s):  
H. Dörner ◽  
S. Hülsmann ◽  
F. Hölker ◽  
C. Skov ◽  
A. Wagner
Keyword(s):  
Prey Fish ◽  
Predator Prey ◽  
Size Dependent

COMPARATIVE MORPHOLOGY OF THE OVIPOSITOR OF SOME PARASITIC HYMENOPTERA IN RELATION TO CHARACTERISTICS OF THEIR HOSTS

1996 ◽  
Vol 128 (3) ◽  
pp. 413-433 ◽  
Author(s):  
A. Le Ralec ◽  
J.M. Rabasse ◽  
E. Wajnberg
Keyword(s):  
Correspondence Analysis ◽  
Morphological Traits ◽  
Morphological Characteristics ◽  
Comparative Morphology ◽  
Interspecific Variation ◽  
Morphological Variations ◽  
Parasitic Hymenoptera ◽  
Different Types ◽  
Host Characteristics

AbstractAlthough the structure of the ovipositor of parasitic Hymenoptera is largely uniform, interspecific variation in its morphology can be observed. Such variability may be related to the diversity of hosts attacked. To verify such an hypothesis, we compared, using correspondence analysis, the morphological characteristics of the ovipositors of 20 species in three categories: (i) species belonging to the same taxonomic unit and attacking the same type of host, (ii) species belonging to the same taxonomic unit but attacking different types of host, and (iii) species belonging to different taxonomic units but attacking the same type of host. Results show that variability in some morphological traits of the ovipositor can be related to host characteristics. Adaptive convergence in morphological variations observed between species is discussed.

scholarly journals Human shields mediate sexual conflict in a top predator

2016 ◽  
Vol 283 (1833) ◽  
pp. 20160906 ◽  
Author(s):  
S. M. J. G. Steyaert ◽  
M. Leclerc ◽  
F. Pelletier ◽  
J. Kindberg ◽  
S. Brunberg ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Sexual Conflict ◽  
Resource Selection ◽  
Ursus Arctos ◽  
Brown Bear ◽  
Offspring Survival ◽  
Adult Males ◽  
Predator Prey ◽  
Cascading Effects ◽  
Survival And Reproduction

Selecting the right habitat in a risky landscape is crucial for an individual's survival and reproduction. In predator–prey systems, prey often can anticipate the habitat use of their main predator and may use protective associates (i.e. typically an apex predator) as shields against predation. Although never tested, such mechanisms should also evolve in systems in which sexual conflict affects offspring survival. Here, we assessed the relationship between offspring survival and habitat selection, as well as the use of protective associates, in a system in which sexually selected infanticide (SSI), rather than interspecific predation, affects offspring survival. We used the Scandinavian brown bear ( Ursus arctos ) population with SSI in a human-dominated landscape as our model system. Bears, especially adult males, generally avoid humans in our study system. We used resource selection functions to contrast habitat selection of GPS-collared mothers that were successful (i.e. surviving litters, n = 19) and unsuccessful (i.e. complete litter loss, n = 11) in keeping their young during the mating season (2005–2012). Habitat selection was indeed a predictor of litter survival. Successful mothers were more likely to use humans as protective associates, whereas unsuccessful mothers avoided humans. Our results suggest that principles of predator–prey and fear ecology theory (e.g. non-consumptive and cascading effects) can also be applied to the context of sexual conflict.

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