Tests for Species Interactions: Breeding Phenology and Habitat Use in Subarctic Ducks

1982 ◽  
Vol 120 (5) ◽  
pp. 586-613 ◽  
Author(s):  
Catherine A. Toft ◽  
David L. Trauger ◽  
Horatio W. Murdy
2003 ◽  
Vol 54 (7) ◽  
pp. 797 ◽  
Author(s):  
Stephanie E. Hampton ◽  
Ian C. Duggan

Most studies of pond animals are undertaken during the daytime, despite evidence that many pond organisms demonstrate marked nocturnal changes in behaviour. Nocturnal studies of animals in fishless ponds are particularly rare, probably because diel changes in aquatic animal behaviour are often found to be a response to visual predation by fish. We used non-metric multidimensional scaling (MDS) and analysis of similarity (ANOSIM) to detect patterns of similarity in the community composition of macroinvertebrates and amphibians in samples taken from vegetated and unvegetated areas during the day and night in a fishless Vermont pond. We tested the hypotheses that (i) macrofaunal activity increased at night near the pond surface, and (ii) horizontal movement of the pond community was occurring on a diel cycle. At night, many taxa were more abundant in the surface waters and the community showed a general habitat expansion or shift from the littoral zone towards the edge and central waters. Our results challenge the assumptions that one would make about pond animal habitat use and interactions based solely on daytime studies. Even in fishless systems, where diel changes are unexpected, habitat use and behaviour might change at night and affect the strength and variety of species interactions.


2016 ◽  
Vol 544 ◽  
pp. 197-211 ◽  
Author(s):  
A Chin ◽  
MR Heupel ◽  
CA Simpfendorfer ◽  
AJ Tobin

2019 ◽  
Vol 609 ◽  
pp. 239-256 ◽  
Author(s):  
TL Silva ◽  
G Fay ◽  
TA Mooney ◽  
J Robbins ◽  
MT Weinrich ◽  
...  

2020 ◽  
Vol 655 ◽  
pp. 139-155
Author(s):  
DC Yates ◽  
SI Lonhart ◽  
SL Hamilton

Marine reserves are often designed to increase density, biomass, size structure, and biodiversity by prohibiting extractive activities. However, the recovery of predators following the establishment of marine reserves and the consequent cessation of fishing may have indirect negative effects on prey populations by increasing prey mortality. We coupled field surveys with empirical predation assays (i.e. tethering experiments) inside and outside of 3 no-take marine reserves in kelp forests along the central California coast to quantify the strength of interactions between predatory fishes and their crustacean prey. Results indicated elevated densities and biomass of invertebrate predators inside marine reserves compared to nearby fished sites, but no significant differences in prey densities. The increased abundance of predators inside marine reserves translated to a significant increase in mortality of 2 species of decapod crustaceans, the dock shrimp Pandalus danae and the cryptic kelp crab Pugettia richii, in tethering experiments. Shrimp mortality rates were 4.6 times greater, while crab mortality rates were 7 times greater inside reserves. For both prey species, the time to 50% mortality was negatively associated with the density and biomass of invertebrate predators (i.e. higher mortality rates where predators were more abundant). Video analyses indicated that macro-invertivore fishes arrived 2 times faster to tethering arrays at sites inside marine reserves and began attacking tethered prey more rapidly. The results indicate that marine reserves can have direct and indirect effects on predators and their prey, respectively, and highlight the importance of considering species interactions in making management decisions.


2020 ◽  
Vol 642 ◽  
pp. 227-240
Author(s):  
L Lodi ◽  
R Tardin ◽  
G Maricato

Most studies of cetacean habitat use do not consider the influence of anthropogenic activities. We investigated the influence of environmental and anthropogenic variables on habitat use by humpback Megaptera novaeangliae and Bryde’s whales Balaenoptera brydei off the coast of the Brazilian city of Rio de Janeiro. Although there are 2 marine protected areas (MPAs) in this area, few data are available on cetacean habitat use or on the overlap of different cetacean species within these MPAs. Our aim was to evaluate the effectiveness of the MPAs and propose a buffer zone to better protect the biodiversity of the study area. We conducted systematic surveys and developed spatial eigenvector generalized linear models to characterize habitat use by the species in the study area. Habitat use by humpback whales was influenced only by depth, whereas for Bryde’s whales there was the additional influence of anthropogenic variables. For Bryde’s whales, which use the area for feeding, sea surface temperature and the distance to anchorages had a major influence on habitat use. We also showed that neither of the MPAs in the study area adequately protects the hotspots of either whale species. Most of the humpback whale grid cells with high sighting predictions were located within 2 km of the MPAs, while areas of high sighting prediction of Bryde’s whales were located up to 5 km from the MPAs, closer to beaches. Our findings provide important insights for the delimitation of protected areas and zoning of the MPAs.


Sign in / Sign up

Export Citation Format

Share Document