Intraspecific variation in diel patterns of rocky reef use suggests temporal partitioning in Port Jackson sharks

Intra- and interspecifically, larger-bodied predators generally occupy higher trophic positions (TPs). With widespread declines in large predators, there is a need to understand their size-based trophic roles to predict ecosystem-level responses. In British Columbia, Canada, we examined size-based trophic interactions between predatory fishes—3 rockfish species (genus Sebastes) and lingcod Ophiodon elongatus—and their prey, converting predator δ15N signatures to TP and analyzing stomach contents. Intraspecifically, TP scaled positively with predator length and gape width, but the rates of change varied by species. Interspecifically, TP did not scale positively with the observed mean sizes or known maximum sizes of species. Lingcod TP was lower than that of yelloweye and quillback rockfishes, which were 51 and 37%, respectively, smaller than lingcod. Yellowtail rockfish had the smallest average size, yet their mean TP did not differ significantly from that of lingcod. Neither species differences in some morphometric traits known to influence body size-TP relationships nor phylogenetic history explained these results. Most prey consumed were <20% of the predator’s size, which might partially explain the lack of a size-based trophic hierarchy among species. Currently, large size classes of rockfishes are being lost due to fisheries and perhaps climate-driven changes. Our findings on intraspecific size-TP relationships indicate that fishery removals of large individuals may diminish trophic structures. Interspecific comparisons of TP suggest that, along with size, species remain an important factor in understanding trophic dynamics. In addition, smaller-bodied predator species may have significant ecological roles to be considered in ecosystem-based fisheries management.

Download Full-text

Convict Settlers, Seamen's Greens, and Imperial Designs at Port Jackson: A Maritime Perspective of British Settler Agriculture

Agricultural History ◽

10.1525/ah.2004.78.3.261 ◽

2004 ◽

Vol 78 (3) ◽

pp. 261-288 ◽

Cited By ~ 3

Author(s):

ANGUS R. McGILLIVERY

Keyword(s):

Port Jackson

Download Full-text

Faculty Opinions recommendation of The ecological importance of intraspecific variation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.732227334.793578012 ◽

2020 ◽

Author(s):

Nelson Hairston Jr

Keyword(s):

Intraspecific Variation ◽

Ecological Importance

Download Full-text

Complete Chloroplast Genome of Japanese Larch (Larix kaempferi): Insights into Intraspecific Variation with an Isolated Northern Limit Population

Forests ◽

10.3390/f11080884 ◽

2020 ◽

Vol 11 (8) ◽

pp. 884

Author(s):

Shufen Chen ◽

Wataru Ishizuka ◽

Toshihiko Hara ◽

Susumu Goto

Keyword(s):

Chloroplast Genome ◽

Intraspecific Variation ◽

Japanese Larch ◽

Monophyletic Group ◽

Phylogenetic Position ◽

Larix Kaempferi ◽

Northern Limit ◽

Complete Chloroplast Genome ◽

Intraspecific Variations ◽

Cpdna Markers

Research Highlights: The complete chloroplast genome for eight individuals of Japanese larch, including from the isolated population at the northern limit of the range (Manokami larch), revealed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed in Japanese larch. We detected intraspecific variation for possible candidate cpDNA markers in Japanese larch. Background and Objectives: The natural distribution of Japanese larch is limited to the mountainous range in the central part of Honshu Island, Japan, with an isolated northern limit population (Manokami larch). In this study, we determined the phylogenetic position of Manokami larch within Japanese larch, characterized the chloroplast genome of Japanese larch, detected intraspecific variation, and determined candidate cpDNA markers. Materials and Methods: The complete genome sequence was determined for eight individuals, including Manokami larch, in this study. The genetic position of the northern limit population was evaluated using phylogenetic analysis. The chloroplast genome of Japanese larch was characterized by comparison with eight individuals. Furthermore, intraspecific variations were extracted to find candidate cpDNA markers. Results: The phylogenetic tree showed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed, based on the complete chloroplast genome, with a bootstrap value of 100%. The value of nucleotide diversity (π) was calculated at 0.00004, based on SNP sites for Japanese larch, suggesting that sequences had low variation. However, we found three hyper-polymorphic regions within the cpDNA. Finally, we detected 31 intraspecific variations, including 19 single nucleotide polymorphisms, 8 simple sequence repeats, and 4 insertions or deletions. Conclusions: Using a distant genotype in a northern limit population (Manokami larch), we detected sufficient intraspecific variation for the possible candidates of cpDNA markers in Japanese larch.

Download Full-text

The impact of potting for crustaceans on temperate rocky reef habitats: Implications for management

Marine Environmental Research ◽

10.1016/j.marenvres.2020.105134 ◽

2020 ◽

Vol 162 ◽

pp. 105134

Author(s):

Sarah C. Gall ◽

Lynda D. Rodwell ◽

Sarah Clark ◽

Tim Robbins ◽

Martin J. Attrill ◽

...

Keyword(s):

Rocky Reef ◽

Temperate Rocky Reef ◽

The Impact

Download Full-text

Effects of heavy metal-mediated intraspecific variation in leaf litter on the feeding preferences of stream detritivores

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.144591 ◽

2021 ◽

Vol 763 ◽

pp. 144591

Author(s):

Run Liu ◽

Yueting Pan ◽

You Fang ◽

Lu Pang ◽

Jiachen Shen ◽

...

Keyword(s):

Heavy Metal ◽

Leaf Litter ◽

Intraspecific Variation ◽

Feeding Preferences

Download Full-text

Intraspecific variation in the Cambrian: new observations on the morphology of the Chengjiang euarthropod Sinoburius lunaris

BMC Ecology and Evolution ◽

10.1186/s12862-021-01854-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Michel Schmidt ◽

Yu Liu ◽

Xianguang Hou ◽

Joachim T. Haug ◽

Carolin Haug ◽

...

Keyword(s):

Intraspecific Variation ◽

Southwest China ◽

3D Models ◽

Morphological Characters ◽

Open Questions ◽

New Findings ◽

Unique Shape ◽

Variable Species ◽

Chengjiang Biota ◽

3D Software

Abstract Background The Chengjiang biota from southwest China (518-million-years old, early Cambrian) has yielded nearly 300 species, of which more than 80 species represent early chelicerates, crustaceans and relatives. The application of µCT-techniques combined with 3D software (e.g., Drishti), has been shown to be a powerful tool in revealing and analyzing 3D features of the Chengjiang euarthropods. In order to address several open questions that remained from previous studies on the morphology of the xandarellid euarthropod Sinoburius lunaris, we reinvestigated the µCT data with Amira to obtain a different approach of visualization and to generate new volume-rendered models. Furthermore, we used Blender to design 3D models showing aspects of intraspecific variation. Results New findings are: (1) antennulae consist of additional proximal articles that have not been detected before; (2) compared to other appendages, the second post-antennular appendage has a unique shape, and its endopod is comprised of only five articles (instead of seven); (3) the pygidium bears four pairs of appendages which are observed in all specimens. On the other hand, differences between specimens also have been detected. These include the presence/absence of diplotergites resulting in different numbers of post-antennular appendages and tergites and different distances between the tip of the hypostome and the anterior margin of the head shield. Conclusions Those new observations reveal intraspecific variation among Chengjiang euarthropods not observed before and encourage considerations about possible sexual dimorphic pairs or ontogenetic stages. Sinoburius lunaris is a variable species with respect to its morphological characters, cautioning that taxon-specific variabilities need to be considered when exploring new species.

Download Full-text