Inference from habitat-selection analysis depends on foraging strategies

Sexual segregation in ungulates has been documented for many species including bison. However, male and female bison do not differ in their pattern of habitat selection. In the present study we observed that a fraction of bison groups did not have young (<2 years) despite the presence of males and females. The male to female ratio in these groups was 2.4. We call them adult groups, in contrast to mixed groups, where young were present and the male to female ratio was 0.4. The proportion of cows with young (mothers) in a group was negatively correlated with the male to female ratio, suggesting that mothers associated more often with other cows than with bulls. Before the rut, cows without young (non-mothers) spent less time feeding than either mothers or bulls. However, mothers and non-mothers did not differ in the number of steps per minute they took while grazing, and both types of cows stepped faster than bulls. We suggest that cows feed more selectively than bulls and that the differing foraging strategies result in temporal but not spatial segregation of the sexes. Possibly as a result of similar nutritional demands, mothers tended to aggregate, forming nursery groups. We suggest that the formation of nursery groups can also serve to protect calves through a dilution effect of predation. Whether mothers actually prefer to associate with other mothers remains to be investigated.

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Habitat Selection by the Ringed Kingfisher (Megaceryle torquata stictipennis) in Basse-Terre, Guadeloupe: Possible Negative Association with Chlordecone Pollution

10.1101/2020.04.15.038729 ◽

2020 ◽

Author(s):

Pascal Villard ◽

Alain Ferchal ◽

Philippe Feldmann ◽

Claudie Pavis ◽

Christophe Bonenfant

Keyword(s):

Habitat Selection ◽

Total Population ◽

Negative Association ◽

Lesser Antilles ◽

Organochlorine Insecticide ◽

Ecological Consequences ◽

Negatively Associated ◽

Selection Analysis ◽

Banana Plantations ◽

Ombrophilous Forest

AbstractIn the Lesser Antilles the Ringed Kingfisher Megaceryle torquata stictipennis is found on Martinique, Dominica and Guadeloupe. On Martinique and Guadeloupe, farmers growing bananas have made massive use of chlordecone from 1973 until 1993. Chlordecone is a remnant organochlorine insecticide which bioaccumulates in organisms easily. We carried out a survey of the Ringed Kingfisher in 2009 on Basse-Terre, Guadeloupe, traveling 270 km on 44 rivers to assess the effects of chlordecone on its habitat selection behaviour. We identified 12 territories and estimated the total population to be 54-64 individuals. A habitat selection analysis revealed that the Ringed Kingfishers were located mainly in sections of rivers flowing through the ombrophilous forest, but absent on the ocean shoreline or in the lower parts of rivers. The Ringed Kingfisher’s distribution on Guadeloupe could be negatively associated with areas heavily polluted by the chlordecone. We propose that the widespread use of chlordecone in banana plantations on Guadeloupe between 1973 and 1993 has adverse ecological consequences, and may be responsible for the absence of Ringed Kingfishers in lowland habitat on the island.

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Westland petrel (Procellaria westlandica) foraging behaviour: Patterns and drivers of individual variation

10.26686/wgtn.17204045.v1 ◽

2021 ◽

Author(s):

◽

Douglas Rands

Keyword(s):

Habitat Selection ◽

West Coast ◽

Foraging Behaviour ◽

Sea Surface ◽

Foraging Strategies ◽

Sea Surface Temperatures ◽

The West ◽

Surface Temperatures ◽

Foraging Site ◽

Incidental Mortality

Foraging behaviour can have a major influence on the survival and reproduction of individuals which can ultimately impact the viability of a population. Foraging is particularly challenging for procellariiformes (tube nosed seabirds) who feed on patchily distributed prey in the highly dynamic marine environment. During the breeding season procellariiformes must also increase their foraging effort to raise their chick whilst having a reduced foraging range. As a result, procellariiformes have adopted various foraging strategies, such as dual foraging and sexual foraging dimorphism, to cope with this energy demanding lifestyle. Westland petrels (Procellaria westlandica) are an endangered winter breeding procellariform endemic to the West Coast of New Zealand’s South Island. Unlike other procellariiformes, previous studies have found little evidence of Westland petrels using sexually dimorphic or dual foraging strategies. Furthermore, Westland petrels also display a high level of individual variation in foraging behaviour. To understand why there is so much variation and what factors are driving it, I first examined variation at the population, individual and within individual level to describe and categorise different foraging strategies. I then investigated how factors such as year, sex and foraging site influenced variation. Finally, I examined how oceanic variables influenced habitat selection and foraging characteristics to understand how the environment drives variation in foraging behaviour. Considerable variation was found at all levels. Most of the variation was explained by year with individuals taking shorter foraging trips in 2011 and longer trips in 2015. Females foraged further than males suggesting that there is some degree of sexual foraging segregation occurring in Westland petrels. I also found that the highest variation in foraging behaviour was exhibited by individuals within their core foraging site on the West Coast. Sea surface temperatures were highest at the West Coast foraging site and individuals within this site showed differences in habitat selection among years. Habitat selection at the West Coast site also differed between sexes suggesting that males are outcompeting females for prime foraging spots. Overall, my results indicate that foraging conditions on the West Coast are highly variable likely due to rising sea surface temperatures, marine heatwaves, and the effects of the El Nino-Southern Oscillation. As a result, it is likely that prey availability on the West Coast is unpredictable causing high variation in foraging behaviour and sexual foraging segregation. With climate change, foraging conditions on the West Coast are predicted to get more unpredictable as sea surface temperatures continue to rise and extreme weather events become more frequent. These factors will make foraging increasingly difficult for Westland petrels and could see them rely more on fishery discards as a source of food, increasing their risk of incidental mortality. Conservation management should focus on protecting the petrels core foraging area around the Hokitika canyon to help limit the effects of climate change. Fishery management should also focus on limiting or prohibiting offal discards to prevent the incidental mortality of Westland petrels.

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Westland petrel (Procellaria westlandica) foraging behaviour: Patterns and drivers of individual variation

10.26686/wgtn.17204045 ◽

2021 ◽

Author(s):

◽

Douglas Rands

Keyword(s):

Habitat Selection ◽

West Coast ◽

Foraging Behaviour ◽

Sea Surface ◽

Foraging Strategies ◽

Sea Surface Temperatures ◽

The West ◽

Surface Temperatures ◽

Foraging Site ◽

Incidental Mortality

Foraging behaviour can have a major influence on the survival and reproduction of individuals which can ultimately impact the viability of a population. Foraging is particularly challenging for procellariiformes (tube nosed seabirds) who feed on patchily distributed prey in the highly dynamic marine environment. During the breeding season procellariiformes must also increase their foraging effort to raise their chick whilst having a reduced foraging range. As a result, procellariiformes have adopted various foraging strategies, such as dual foraging and sexual foraging dimorphism, to cope with this energy demanding lifestyle. Westland petrels (Procellaria westlandica) are an endangered winter breeding procellariform endemic to the West Coast of New Zealand’s South Island. Unlike other procellariiformes, previous studies have found little evidence of Westland petrels using sexually dimorphic or dual foraging strategies. Furthermore, Westland petrels also display a high level of individual variation in foraging behaviour. To understand why there is so much variation and what factors are driving it, I first examined variation at the population, individual and within individual level to describe and categorise different foraging strategies. I then investigated how factors such as year, sex and foraging site influenced variation. Finally, I examined how oceanic variables influenced habitat selection and foraging characteristics to understand how the environment drives variation in foraging behaviour. Considerable variation was found at all levels. Most of the variation was explained by year with individuals taking shorter foraging trips in 2011 and longer trips in 2015. Females foraged further than males suggesting that there is some degree of sexual foraging segregation occurring in Westland petrels. I also found that the highest variation in foraging behaviour was exhibited by individuals within their core foraging site on the West Coast. Sea surface temperatures were highest at the West Coast foraging site and individuals within this site showed differences in habitat selection among years. Habitat selection at the West Coast site also differed between sexes suggesting that males are outcompeting females for prime foraging spots. Overall, my results indicate that foraging conditions on the West Coast are highly variable likely due to rising sea surface temperatures, marine heatwaves, and the effects of the El Nino-Southern Oscillation. As a result, it is likely that prey availability on the West Coast is unpredictable causing high variation in foraging behaviour and sexual foraging segregation. With climate change, foraging conditions on the West Coast are predicted to get more unpredictable as sea surface temperatures continue to rise and extreme weather events become more frequent. These factors will make foraging increasingly difficult for Westland petrels and could see them rely more on fishery discards as a source of food, increasing their risk of incidental mortality. Conservation management should focus on protecting the petrels core foraging area around the Hokitika canyon to help limit the effects of climate change. Fishery management should also focus on limiting or prohibiting offal discards to prevent the incidental mortality of Westland petrels.

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Larger foraging range but similar habitat selection in non-breeding versus breeding sub-Antarctic penguins

Antarctic Science ◽

10.1017/s0954102010000957 ◽

2011 ◽

Vol 23 (2) ◽

pp. 117-126 ◽

Cited By ~ 33

Author(s):

Jean-Baptiste Thiebot ◽

Amélie Lescroël ◽

David Pinaud ◽

Philip N. Trathan ◽

Charles-André Bost

Keyword(s):

Habitat Selection ◽

Foraging Strategies ◽

Breeding Period ◽

Mahalanobis Distances ◽

Juvenile Dispersal ◽

Marine Predators ◽

Eudyptes Chrysolophus ◽

Breeding Grounds ◽

Suitability Maps ◽

Suitable Habitats

AbstractFor land-breeding marine organisms such as seabirds, knowledge about their habitat use has mainly been gained through studies of breeding individuals that are constrained to return frequently to their breeding grounds. In this study we set out to measure whether: a) habitat selection in the non-breeding period predicts habitat selection in the breeding period, and b) whether breeding individuals concentrated their activity on the closest suitable habitats. MacaroniEudyptes chrysolophusand gentooPygoscelis papuapenguins, two marine predators with contrasting foraging strategies, were tracked from the Iles Kerguelen and their habitat selection investigated through Mahalanobis distances factorial analysis. This study presents the first data about gentoo penguins’ juvenile dispersal. For both species, results showed 6.9 times larger maximum ranges and up to 12.2 times greater distances travelled during the non-breeding period. Habitat suitability maps suggested both species made similar environmental selections whatever the period. Macaroni penguins targeted pelagic areas beyond the shelf break while gentoo penguins always remained over the shelf. We consider the ecological significance of larger scale movements made outside the breeding period and suggest that this non-breeding period is of particular interest when attempting to understand an animal's habitat selection.

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Florida Panther Habitat Selection Analysis of Concurrent GPS and VHF Telemetry Data

Journal of Wildlife Management ◽

10.2193/2007-136 ◽

2008 ◽

Vol 72 (3) ◽

pp. 633-639 ◽

Cited By ~ 34

Author(s):

E. Darrell Land ◽

David B. Shindle ◽

Robert J. Kawula ◽

John F. Benson ◽

Mark A. Lotz ◽

...

Keyword(s):

Habitat Selection ◽

Telemetry Data ◽

Florida Panther ◽

Selection Analysis

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Robust Inference from Conditional Logistic Regression Applied to Movement and Habitat Selection Analysis

PLoS ONE ◽

10.1371/journal.pone.0169779 ◽

2017 ◽

Vol 12 (1) ◽

pp. e0169779 ◽

Cited By ~ 17

Author(s):

Marie-Caroline Prima ◽

Thierry Duchesne ◽

Daniel Fortin

Keyword(s):

Logistic Regression ◽

Habitat Selection ◽

Conditional Logistic Regression ◽

Robust Inference ◽

Selection Analysis

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Pentastomid infection in Philodryas nattereri Steindachner, 1870 and Oxybelis aeneus (Wagler, 1824) (Squamata: Colubridae) in a caatinga of northeastern Brazil

Brazilian Journal of Biology ◽

10.1590/s1519-69842008000100028 ◽

2008 ◽

Vol 68 (1) ◽

pp. 193-197 ◽

Cited By ~ 10

Author(s):

WO. Almeida ◽

TB. Guedes ◽

EMX. Freire ◽

A. Vasconcellos

Keyword(s):

Habitat Selection ◽

Natural Resources ◽

Rio Grande ◽

Northeastern Brazil ◽

Foraging Strategies ◽

Northeast Brazil ◽

Intensity Of Infection ◽

Mean Intensity ◽

Anatomical Dissection ◽

The Relationship

The relationship between pentastomids and two Colubridae species, Phillodryas nattereri Steindachner, 1870 and Oxybelis aeneus (Wagler, 1824), were investigated in the federal government’s reserve Estação Ecológica do Seridó (ESEC, Seridó) situated at lat 6° 35’-40’ S and long 37° 15’-20 W in the municipality of Serra Negra do Norte, state of Rio Grande do Norte, Northeast Brazil and run by IBAMA (the Brazilian Institute for the Environment and Natural Resources). Throughout 2005, 26 specimens of snakes, 13 of P. nattereri and 13 of O. aeneus were collected. After anatomical dissection and laboratorial examination of the snakes’ respiratory tracts, P. nattereri was found to be parasitized by two species of pentastomids: Cephalobaena tetrapoda Heymons, 1922 with a prevalence of 30.8% and a mean intensity of infection of 51.5 ± 32.7 (range 3-147), and Raillietiella furcocerca (Diesing, 1863) which had a prevalence of 7.7% and a mean intensity of infection of 1.0. Only one female of O. aeneus was found to be infected by C. tetrapoda, with a prevalence of 7.7% and mean intensity of infection of 2.0. There was no significant relationship between size of snout-vent length (SVL) and intensity of infection in the specimens investigated here. The two individuals of P. nattereri infected by more than 40 specimens of pentastomids had their lungs completely infected including the pulmonary peritoneum and trachea. It is noteworthy that the hosts had their lung tissues partially destroyed with apparent haemorrhage, and the trabecular structure of their lungs was also destroyed. The contrasting rates of infection estimated here may be related to differences in foraging strategies, in diet, and habitat selection carried out by individuals of P. nattereri and O. aeneus.

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