Behavioural differences and interactions between two sessile bivalves forming mixed-species assemblages

Low target strength fish in mixed species assemblages: the case of orange roughy

Fisheries Research ◽

10.1016/j.fishres.2004.11.008 ◽

2005 ◽

Vol 72 (2-3) ◽

pp. 185-192 ◽

Cited By ~ 12

Author(s):

S. McClatchie ◽

R.F. Coombs

Keyword(s):

Target Strength ◽

Species Assemblages ◽

Mixed Species ◽

Orange Roughy

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Morph Composition Matters in the Gouldian Finch (Chloebia gouldiae): Involvement of Red-Headed Birds Increases Vigilance

Birds ◽

10.3390/birds2040030 ◽

2021 ◽

Vol 2 (4) ◽

pp. 404-414

Author(s):

Claudia Mettke-Hofmann

Keyword(s):

Predation Risk ◽

Group Composition ◽

Predation Pressure ◽

Head Movements ◽

Species Assemblages ◽

Same Sex ◽

Mixed Species ◽

Polymorphic Species ◽

Gouldian Finch ◽

Tracking Strategy

Animals invest in costly vigilance to detect threats. Joining groups reduces these costs, which can be further reduced in mixed-species assemblages. In colour-polymorphic species, morphs often experience different predation pressure and vary in a variety of traits. However, little is known about differences in vigilance or how group composition affects vigilance. The aim was to investigate whether higher conspicuousness increased vigilance and whether vigilance was reduced in mixed-morph groups like in mixed-species assemblages. I tested vigilance in the colour-polymorphic Gouldian Finch (Chloebia gouldiae). Same sex pairs of different age and of either pure (red-red or black-black) or mixed head colour were exposed to three contexts (familiar, changed and novel environment) and head movements were recorded. All birds reduced the frequency of head movements with increasing novelty, indicating different vigilance strategies (switching from a searching to a tracking strategy) depending on the situation. While vigilance did not differ between morphs, morph composition mattered. Black-headed pairs made fewer head movements than mixed-head colour pairs. Results indicated that conspicuousness did not affect vigilance, possibly due to existing adaptations to reduce predation risk. However, whenever red-headed birds were involved, vigilance increased either because of higher group conspicuousness or prevalence of aggression.

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Cultural learning of predator recognition in mixed-species assemblages of frogs: the effect of tutor-to-observer ratio

Animal Behaviour ◽

10.1016/j.anbehav.2007.10.037 ◽

2008 ◽

Vol 75 (6) ◽

pp. 1921-1925 ◽

Cited By ~ 42

Author(s):

Maud C.O. Ferrari ◽

Douglas P. Chivers

Keyword(s):

Predator Recognition ◽

Species Assemblages ◽

Cultural Learning ◽

Mixed Species

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Assessing introduction risk using species’ rank-abundance distributions

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.1517 ◽

2015 ◽

Vol 282 (1799) ◽

pp. 20141517 ◽

Cited By ~ 12

Author(s):

Farrah T. Chan ◽

Johanna Bradie ◽

Elizabeta Briski ◽

Sarah A. Bailey ◽

Nathalie Simard ◽

...

Keyword(s):

Ballast Water ◽

Lower Risk ◽

Water Exchange ◽

Propagule Pressure ◽

Species Assemblages ◽

Total Abundance ◽

Mixed Species ◽

Colonization Pressure ◽

Rank Abundance

Mixed-species assemblages are often unintentionally introduced into new ecosystems. Analysing how assemblage structure varies during transport may provide insights into how introduction risk changes before propagules are released. Characterization of introduction risk is typically based on assessments of colonization pressure (CP, the number of species transported) and total propagule pressure (total PP, the total abundance of propagules released) associated with an invasion vector. Generally, invasion potential following introduction increases with greater CP or total PP. Here, we extend these assessments using rank-abundance distributions to examine how CP : total PP relationships change temporally in ballast water of ocean-going ships. Rank-abundance distributions and CP : total PP patterns varied widely between trans-Atlantic and trans-Pacific voyages, with the latter appearing to pose a much lower risk than the former. Responses also differed by taxonomic group, with invertebrates experiencing losses mainly in total PP, while diatoms and dinoflagellates sustained losses mainly in CP. In certain cases, open-ocean ballast water exchange appeared to increase introduction risk by uptake of new species or supplementation of existing ones. Our study demonstrates that rank-abundance distributions provide new insights into the utility of CP and PP in characterizing introduction risk.

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