scholarly journals Community–environment interactions explain octopus-catshark spatial overlap

2016 ◽  
Vol 73 (7) ◽  
pp. 1901-1911 ◽  
Author(s):  
Patricia Puerta ◽  
Mary E. Hunsicker ◽  
Manuel Hidalgo ◽  
Patricia Reglero ◽  
Lorenzo Ciannelli ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Spatial Patterns ◽  
Species Interactions ◽  
Species Coexistence ◽  
Feeding Habits ◽  
Western Mediterranean ◽  
Community Diversity ◽  
Ecosystem Functions ◽  
Spatial Overlap ◽  
Phytoplankton Communities

Abstract The octopus Eledone cirrhosa and the catshark Scyliorhinus canicula present the same feeding habits and distributional preferences in the Mediterranean Sea. We explore patterns of spatial overlap between these species to address coexistence and infer possible competition from spatial patterns in the western Mediterranean Sea. A spatially explicit modelling approach revealed that spatial overlap mainly responded to the distribution of shared resources, where coexistence is allowed by different ecological processes. Catshark (k-strategy) was highly abundant and widely distributed. However, the fluctuating population dynamics of octopus (r-strategy) explained the variations in spatial patterns of overlap. Spatial structuring across the study area was observed both in population distributions and in species interactions (coexistence or exclusion). Areas with high resources in terms of specific prey items (Catalan Sea) or alternative supplies, such as niche opportunities and ecosystem functions defined by community diversity (Balearic Islands), favoured species coexistence. Sea surface temperature showed opposite effects on overlap in northern and southern regions of the study area, which were not related to differences in species sensitivity. We suggest a surface trophic link, where different phytoplankton communities at each region might have opposite responses to temperature. This triggers contrasting mechanisms of food transfer to deeper benthic communities that subsequently facilitates species overlap. Characterizing how benthic and pelagic seascape properties shape species interactions across space and time is pivotal to properly address community spatial dynamics and move towards ecosystem-based management for sustainable fisheries and conservation planning.

Feeding Habits of Alepocephalus Rostratus (Pisces: Alepocephalidae) in the Western Mediterranean Sea

1998 ◽  
Vol 78 (4) ◽  
pp. 1295-1306 ◽  
Author(s):  
M. Carrassón ◽  
J. Matallanas
Keyword(s):  
Mediterranean Sea ◽  
Prey Item ◽  
Narrow Range ◽  
Feeding Habits ◽  
Western Mediterranean ◽  
Western Mediterranean Sea ◽  
The Family ◽  
Different Seasons ◽  
Scarcity Of Resources ◽  
Important Fish

The present study examines the feeding habits of Alepocephalus rostratus, the only species of the family Alepocephalidae in the Mediterranean Sea and the second most important fish species, in terms of biomass, inhabiting the deep slope of the Catalan Sea. Samples were obtained at depths between 1000–2250 m. Diet was analysed for two different size-classes (immature and mature specimens) at three different bathymetric strata during two different seasons. The feeding habits of A. rostratus included a narrow range of mobile macroplanktonic organisms (e.g. Pyrosoma atlanticum and Chelophyes appendiculata) and some material of benthic origin. Pyrosoma atlanticum was the preferred prey item in spring at 1000–1425 m, being very scarce in summer at the same depth as a consequence of its scarcity in the environment during this season. There were some ontogenic differences in the diet of A. rostratus at 1425–2250 m. Adults ingested more and larger prey than juvenile specimens. The scarcity of resources below 1200–1400 m fostered a more diversified diet, as well as passive predation of sedimented material.

Feeding habits of the short-finned squidIllex coindetiiin the western Mediterranean Sea using combined stomach content and isotopic analysis

2015 ◽  
Vol 96 (6) ◽  
pp. 1235-1242 ◽  
Author(s):  
Francisco Martínez-Baena ◽  
Joan Navarro ◽  
Marta Albo-Puigserver ◽  
Isabel Palomera ◽  
Rigoberto Rosas-Luis
Keyword(s):  
Mediterranean Sea ◽  
Stomach Content ◽  
Feeding Habits ◽  
Western Mediterranean ◽  
Trophic Levels ◽  
Mesopelagic Fish ◽  
Western Mediterranean Sea ◽  
Isotopic Analyses ◽  
Stable Isotopic ◽  
Prey Items

The ommastrephid squid,Illex coindetii, is one of the most abundant cephalopods in the Mediterranean Sea and an important predator in the ecosystem. In the present study, we examined the diet habits ofI. coindetiiin the north-western Mediterranean Sea by combining two complementary approaches: stomach content and stable isotopic analyses. Specifically, we examined whether the diet differed between sizes and seasons. Stomach content results indicated that the diet ofI. coindetiiwas composed of 35 prey items including four major groups; namely the crustaceansPasiphaea sivado, Amphipods, squid of the Order Teuthida, and pelagic and mesopelagic fish. Differences were found among different ontogenetic sizes: juvenile individuals fed mainly on crustaceans (%IRI = 77.59), whereas adult individuals fed on a wider range of prey items, including the shrimpP. sivado(%IRI = 33.21), the amphipodAnchylomera blossevillei(%IRI = 0.91), the decapodPlesionikasp. (%IRI = 0.19), the carangidTrachurus trachurus(%IRI = 0.34) and some Myctophids species (%IRI = 0.21). Differences were also found between seasons in the year. In winter, crustaceans were the main prey items, whereas in summer the diversity of prey was higher, including fish, crustaceans and molluscs. Similar to the stomach contents, stable isotopic results indicated differences among sizes. δ15N values were higher in adult squids than in juveniles because they fed on prey at higher trophic levels. In conclusion, this study indicates that feeding habits ofI. coindetiivary seasonally and ontogenetically. These feeding variations may be associated with trophic competence scenarios based on size, and also with the availability and abundance of prey throughout the year.

Feeding strategies of Polyacanthonotus rissoanus (Pisces: Notacanthidae) in the deep western Mediterranean

2002 ◽  
Vol 82 (4) ◽  
pp. 665-671 ◽  
Author(s):  
M. Carrassón ◽  
J. Matallanas
Keyword(s):  
Mediterranean Sea ◽  
Feeding Habits ◽  
Abundant Species ◽  
Western Mediterranean ◽  
Feeding Strategies ◽  
Important Food ◽  
Food Items ◽  
The Mediterranean ◽  
Scarcity Of Resources

The feeding habits of Polyacanthonotus rissoanus, the sixth most abundant species below 1000 m on the deep slope of the Catalan Sea (western Mediterranean), were studied in the Mediterranean Sea. Samples were obtained at depths between 1000 and 2250 m. Diet was analysed for two seasons (summer and autumn) and three different bathymetric strata. The most important food items found were small epibenthic and suprabenthic crustaceans and polychaetes, and occasionally other groups such as Priapulida, Gastropoda and Foraminifera. At 1000–1425 m, the mysids were preferential prey, while in summer at all depths analysed, isopods were a dominant prey. Polychaetes have certain incidence in the diet only at 1000–1425 m, being a dominant prey in autumn. Individuals at the 1000–1425 m depth ingest larger numbers of prey of higher average sizes than those at 1425–2250 m. The scarcity of resources below 1200–1400 m resulted in diversification of diet and encouraged preying on deposited foraminiferans, molluscs or moving copepods.

scholarly journals Habitat loss alters effects of intransitive higher-order competition on biodiversity: a new metapopulation framework

2020 ◽  
Vol 287 (1940) ◽  
pp. 20201571
Author(s):  
Yinglin Li ◽  
Daniel Bearup ◽  
Jinbao Liao
Keyword(s):  
Habitat Loss ◽  
Species Interactions ◽  
Species Coexistence ◽  
Interaction Model ◽  
Higher Order ◽  
Community Diversity ◽  
Rapid Decline ◽  
Order Effects ◽  
Vital Rates ◽  
Model Framework

Recent studies have suggested that intransitive competition, as opposed to hierarchical competition, allows more species to coexist. Furthermore, it is recognized that the prevalent paradigm, which assumes that species interactions are exclusively pairwise, may be insufficient. More importantly, whether and how habitat loss, a key driver of biodiversity loss, can alter these complex competition structures (and therefore species coexistence) remain unclear. We thus present a new, simple yet comprehensive metapopulation framework that can account for any competition pattern and more complex higher-order interactions (HOIs) among species. We find that competitive intransitivity increases community diversity and that HOIs generally enhance this effect. Essentially, intransitivity promotes species richness by preventing the dominance of a few species, unlike the hierarchical competition, while HOIs facilitate species coexistence through stabilizing community fluctuations. However, variation in species’ vital rates and habitat loss can weaken or even reverse such higher-order effects, as their interaction can lead to a more rapid decline in competitive intransitivity under HOIs. Thus, it is essential to correctly identify the most appropriate interaction model for a given system before models are used to inform conservation efforts. Overall, our simple model framework provides a more parsimonious explanation for biodiversity maintenance than the existing theory.

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