Article

Feral cats threaten the outstanding endemic fauna of the New Caledonia biodiversity hotspot

October 2017
Biological Conservation 214(10):250–259

DOI: 10.1016/j.biocon.2017.08.003

Authors:

Pauline Palmas

University of French Polynesia

Hervé Jourdan

Institute of Research for Development

Frédéric Rigault

Institute of Research for Development

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Feral cats (Felis catus) are one of the most successful and harmful invasive predator species, leading to dramatic loss of biodiversity across the globe. Our study assessed feral cat predation in a major biodiversity hotspot: the New Caledonian archipelago. We focused on the consequences of this predation for the outstanding endemic fauna found throughout the rich range of New Caledonian natural habitats. We analyzed> 5300 cat scats sampled from 14 selected sites representing the 4 main natural habitats, with 4 to 6 sampling sessions per year over> 4 years per habitat. Our study reveals previously unreported patterns of cat predation on both alien and endemic species. Throughout the archipelago, cats prey strongly upon squamates, flying foxes and petrels. Feral cat prey included at least 44 native vertebrate species, 20 of which are IUCN Red-listed threatened species. This study adds some 44.4% to the number of IUCN threatened species vulnerable to and preyed upon by feral cats on the world's islands. New Caledonia, while it represents only 0.12% of the total area of islands worldwide. (Australia included), hosts 30.8% of IUCN threatened species known to be predated by feral cats. This study recommends prioritizing management and conservation strategies by focusing actions on maquis mosaic and humid forest habitats, where feral cats pose the greatest threat. To limit the impact of feral cats, we ecommend conducting targeted management actions on sites key to threatened species conservation, and preventing arrival or promoting eradication on islets.

Impacts and management of unowned and owned cats at a seabird colony on Reunion Island (Western Indian Ocean)

Article

Full-text available

Aug 2022
BIOL INVASIONS

Cats (Felis catus) introduced on islands have strong impacts on biodiversity, and the main conservation actions to protect native fauna is cat eradication or control (i.e., regular culling). The situation is more complicated on inhabited islands because unowned cats coexist with owned cats. The social acceptance of cat control implies separating the impacts of unowned and owned cats. We investigated the spatial ecology and impacts of owned and unowned cats at a seabird colony in a periurban area on Reunion Island (Indian Ocean). We used multiple methodologies to investigate this question: GPS-tracking of cats, camera-traps at seabird nests, cat scat analysis and cat control. Owned cats had small home ranges and did not forage at the seabird colony. Unowned cats had larger home ranges and foraged at seabird colony. We identified two kinds of unowned cats, stray cats and semi-feral cats. Stray cats relied on food waste and rarely foraged at seabird colony. Semi-feral cats foraged mostly in natural habitats, including the seabird colony and rarely used food waste. Semi-feral cats were very active at the seabird colony and several preyed upon seabirds. Restaurants are an abundant source of food for cats and help sustain populations of unowned cats. Control of unowned cats during this study resulted in reduced cat activity at the seabird colony. To minimize negative impacts of cats on seabirds, our results suggest that the most effective strategy includes the permanent control of unowned cats, efficient management of food waste and sterilization of owned cats.

Rapid Recolonisation of Feral Cats Following Intensive Culling in a Semi-Isolated Context

Article

Full-text available

Dec 2020

Invasive feral cats threaten biodiversity at a global scale. Mitigating feral cat impacts and reducing their populations has therefore become a global conservation priority, especially on islands housing high endemic biodiversity. The New Caledonian archipelago is a biodiversity hotspot showing outstanding terrestrial species richness and endemism. Feral cats prey upon at least 44 of its native vertebrate species, 20 of which are IUCN Red-listed threatened species. To test the feasibility and efficiency of culling, intensive culling was conducted in a peninsula of New Caledonia (25.6 km²) identified as a priority site for feral cat management. Live-trapping over 38 days on a 10.6 km² area extirpated 36 adult cats, an estimated 44% of the population. However, three months after culling, all indicators derived from camera-trapping (e.g., abundance, minimum number of individuals and densities) suggest a return to pre-culling levels. Compensatory immigration appears to explain this unexpectedly rapid population recovery in a semi-isolated context. Since culling success does not guarantee a long-term effect, complementary methods like fencing and innovative automated traps need to be used, in accordance with predation thresholds identified through modelling, to preserve island biodiversity. Testing general assumptions on cat management, this article contributes important insights into a challenging conservation issue for islands and biodiversity hotspots worldwide.

A conservation paradox: endangered and iconic flightless kagu (Rhynochetos jubatus) apparently escape feral cat predation

Article

Full-text available

Feb 2020
NEW ZEAL J ECOL

The kagu (Rhynochetos jubatus) is an iconic endemic flightless bird from New Caledonia, red-listed as endangered according to the International Union for Conservation of Nature (IUCN) criteria. Feral cats are among the most successful and damaging invaders for island biodiversity. They have been directly responsible for the extinction of numerous birds worldwide, especially small- and medium-sized flightless species. Our study evaluates the feral cat threat to the kagu by analysing 772 cat scats from the two main sites housing major remaining populations (eight quarterly sampling sessions conducted per site over 2 years). Surprisingly, we detected no predation evidence against this endangered species (including chicks) although it falls within the cats' prey size range and exhibits life-history traits typical of island endangered naïve birds. We recommend a multi-species approach to invasive mammal management to mitigate direct and indirect pressures against remaining kagu populations.

Tahiti Petrel Pseudobulweria rostrata population decline at a nickel-mining site: a critical need for adapted conservation strategies

Article

Full-text available

Apr 2021

New Caledonia hosts a large part of the world’s breeding population of the Tahiti Petrel Pseudobulweria rostrata. This rare, cryptic and little-studied seabird nests locally in the mountains up to 1,200 m in altitude, particularly in ultramafic (i.e. nickel-rich) areas where mining activity is a major threat. The considerable development of mining activities in New Caledonia over the past decade raises concerns about its potential impacts on breeding populations through both direct habitat destruction and side effects such as pollution or repeated disturbances. This context calls for a dedicated assessment of the persistence of local populations to guide the design of an adapted conservation strategy and potential restoration programmes. We investigated the impact of mining activities on a Tahiti Petrel population when surveyed pre-mining (2004–2007) and following a period of full mining (2017–2018). The vocal activity was assessed at a total of 114 night-call count stations spread over the Koniambo massif. Areas with ground-originated vocal activity were then searched during daytime for nesting evidence. Finally, georeferenced aerial photos were used to estimate habitat degradation as the percentage of bare soil cover (PBSC) within a 400-m radius around each call count station. Our study revealed a dramatic decline in the Tahiti Petrel vocal activity and a desertion of breeding habitats during the full-mining period compared to the pre-mining period. In light of these results, we recommend designing safe breeding areas and combining restoration methods including social attraction, predation control and artificial burrows at mining sites.

A novel dataset to identify the endemic herpetofauna of the New Caledonia biodiversity hotspot with DNA barcodes

Article

Mar 2021

New Caledonia is the smallest global biodiversity hotspot, yet has one of the highest levels of endemism for an insular region of its size. Lizards are the dominant vertebrate fauna, and, while ecologically important, can be difficult to identify and many are in decline due to anthropogenic threats. As an aid to facilitate identification, we generated a near complete DNA barcode dataset for New Caledonian lizards, consisting of 601 mitochondrial CO1 sequences of 100 of the 5 107 described lizards, and a number of yet undescribed species. We use this dataset to assess the performance of CO1 in delimiting species recognised by other, more extensive data and in recovering phylogenetic signal. Most species had intraspecific genetic distances ≤3.7%. Most comparisons between described species were at least ~5% divergent, with the exception of three pairwise species comparisons showing interspecific distances >2.5%. Maximum likelihood CO1 trees of the six most speciose genera recovered each as monophyletic and, although discordant with previously published 10 ND2 trees using quantitative topology tests, showed similar patterns of intraspecific and interspecific divergence, supporting the utility of CO1 in taxonomic identification and species delimitation. Some species showed overlap between intra- and interspecific pairwise distances, suggesting cryptic taxa, a finding also supported by species delimitation analyses using GMYC and mPTP. This dataset not only provides the basis for economical and reliable identification of New Caledonian lizards encountered during biodiversity assessments, but also provides a potential tool for investigating 15 the identity of native lizards and their ecosystem interactions, even from partial remains.

Cats Felis catus as a threat to bats worldwide: a review of the evidence

Article

Feb 2021

en • Cats Felis catus, in all their forms (domestic, free‐roaming/stray and feral), have been identified as a major global threat to biodiversity, especially birds and small mammals. However, there has been little previous consideration of the extent and impact of predation of bats by cats, or of whether specific characteristics make certain species of bats particularly vulnerable to predation by cats. • We reviewed the impact of cats on bats, based on a collation of scientific literature and the International Union for Conservation of Nature (IUCN) Red List database. Our aim was to produce a synthesis of the extent to which cats prey upon and threaten bats. We also collated available data on cat diet, which provide information on predation rates of bats by cats. • Few studies (n = 44) have identified bat species preyed upon or threatened by cats, with a disproportionate number of studies from islands. In these studies, 86 bat species (about 7% of the global extant tally) are reported as preyed upon or threatened by cats, and about one quarter of these species are listed as Near Threatened or threatened (IUCN categories Critically Endangered, Endangered, or Vulnerable). In IUCN Red List assessments, cats are more frequently mentioned as a threat to threatened or Near Threatened bat species than to non‐threatened species (IUCN category Least Concern). • In studies reporting on the incidence of bats in cat dietary samples (scats, stomachs and guts), the frequency of occurrence of bats in samples averaged 0.7 ± 2.1% (mean ± standard deviation; n = 102). Many studies had sample sizes that were too small to be likely to detect bats. • All forms of cat are reported to kill bats, and such predation has been reported in all major terrestrial habitats. We conclude that predation by cats is an under‐appreciated threat to the world’s bat species. Abstract fr RESUMÉ EN FRANÇAIS • Les chats Felis catus, sous toutes leurs formes (domestiques, errants ou harets), ont été identifiés comme une menace mondiale majeure pour la biodiversité, en particulier pour les oiseaux et les petits mammifères. Cependant, l'ampleur de ce phénomène et l'impact de la prédation exercée sur les chauves‐souris par les chats n'ont guère été pris en compte jusqu'à présent. En particulier la question de savoir si des caractéristiques spécifiques rendent certaines espèces de chauves‐souris particulièrement vulnérables à la prédation par les chats reste en suspens. • Nous avons examiné l'impact des chats sur les chauves‐souris, en croisant les informations issues de la littérature scientifique sur le sujet et celles disponibles dans la base de données de la liste rouge de l'Union Internationale pour la Conservation de la Nature (UICN). Notre objectif était de produire une synthèse mondiale visant à estimer dans quelle mesure les chats s'attaquent aux chauves‐souris et constituent une menace. Nous avons également rassemblé les données disponibles sur le régime alimentaire des chats, qui fournissent des informations sur les taux de prédation des chauves‐souris par les chats. • Peu d'études (n = 44) ont permis d’identifier des espèces de chauves‐souris prédatées et/ou menacées par les chats, un nombre disproportionné d’entre elles concernent les écosystèmes insulaires. Ces études ont permis d’identifier 86 espèces de chauves‐souris (environ 7 % des espèces mondiales) représentant des proies ou étant directement menacées par les chats ; environ un quart de ces espèces sont classées comme "quasi menacées" ou "menacées" (catégories de l'UICN : En danger critique d'extinction, En danger ou Vulnérable). Dans les évaluations de la Liste rouge de l'UICN, les chats sont plus fréquemment mentionnés comme une menace pour les espèces de chauves‐souris menacées ou quasi menacées que pour les espèces non menacées (catégorie de l'UICN "Préoccupation mineure"). • Dans les études analysant le régime alimentaire des chats (excréments, estomacs et tubes digestifs) la fréquence d'occurrence des chauves‐souris dans les échantillons était en moyenne de 0.7 ± 2.1 % (moyenne ± écart‐type ; n = 102). Dans de nombreux travaux, la taille des échantillons était trop petite pour permettre de détecter la prédation sur des chauves‐souris. • Toutes les formes de chats s'attaquent aux chauves‐souris, et cette prédation a été signalée dans tous les principaux habitats terrestres. En conclusion, la prédation des chauves‐souris par les chats apparait être une menace sous‐estimée au niveau mondial.

Introduced cats eating a continental fauna: Invertebrate consumption by feral cats (Felis catus) in Australia

Article

Oct 2020
WILDLIFE RES

Context. Recent global concern over invertebrate declines has drawn attention to the causes and consequences of this loss of biodiversity. Feral cats, Felis catus, pose a major threat to many vertebrate species in Australia, but their effect on invertebrates has not previously been assessed. Aims. The objectives of our study were to (1) assess the frequency of occurrence (FOO) of invertebrates in feral cat diets across Australia and the environmental and geographic factors associated with this variation, (2) estimate the number of invertebrates consumed by feral cats annually and the spatial variation of this consumption, and (3) interpret the conservation implications of these results. Methods. From 87 Australian cat-diet studies, we modelled the factors associated with variation in invertebrate FOO in feral cat-diet samples. We used these modelled relationships to predict the number of invertebrates consumed by feral cats in largely natural and highly modified environments. Key results. In largely natural environments, the mean invertebrate FOO in feral cat dietary samples was 39% (95% CI: 31–43.5%), with Orthoptera being the most frequently recorded order, at 30.3% (95% CI: 21.2–38.3%). The highest invertebrate FOO occurred in lower-rainfall areas with a lower mean annual temperature, and in areas of greater tree cover. Mean annual invertebrate consumption by feral cats in largely natural environments was estimated to be 769 million individuals (95% CI: 422–1763 million) and in modified environments (with mean FOO of 27.8%) 317 million invertebrates year-1, giving a total estimate of 1086 million invertebrates year-1 consumed by feral cats across the continent. Conclusions. The number of invertebrates consumed by feral cats in Australia is greater than estimates for vertebrate taxa, although the biomass (and, hence, importance for cat diet) of invertebrates taken would be appreciably less. The impact of predation by cats on invertebrates is difficult to assess because of the lack of invertebrate population and distribution estimates, but cats may pose a threat to some large-bodied narrowly restricted invertebrate species. Implications. Further empirical studies of local and continental invertebrate diversity, distribution and population trends are required to adequately contextualise the conservation threat posed by feral cats to invertebrates across Australia.

Precipitation and prey abundance influence food habits of an invasive carnivore

Article

Apr 2019

Invasive predators threaten biodiversity worldwide, and generalist invasive predators are often more successful due to their broad diets. Predation patterns can be influenced by prey abundance, prey preference, and climate, and understanding these relationships is integral to conserving native prey species. We examined stomach contents of 2882 feral cats Felis catus from San Clemente Island, California, to assess how their diets varied annually and seasonally, and how precipitation and prey abundance influenced predation patterns. Rodents were found in 95% (n = 2589) of stomachs containing prey. The endemic San Clemente deer mouse Peromyscus maniculatus clementis was the most prevalent prey species and was found in 85% (n = 2589) of stomachs containing prey. Consumption of rodents, lizards, and birds varied annually. In years following dry winters, consumption of rodents decreased and consumption of lizards increased. This had a particularly strong effect on endemic night lizards Xantusia riversiana reticulata with 20.4% (n = 1952) of non‐empty cat stomachs containing night lizards following normal years, and 43.7% (n = 602) following dry years. Consumption of rodents peaked in fall, while consumption of lizards and birds peaked in spring. Using rodenticide removed from bait stations as an index of rodent abundance, we found a positive correlation between bait removal and the number of rodents consumed by cats, and a negative correlation between bait removal and the number of lizards consumed by cats. These results suggest that feral cats use rodents as primary prey and lizards as secondary prey, particularly during droughts when rodent abundance is low. Understanding how weather patterns affect invasive species predation patterns will help conservation biologists predict and manage for the effects of invasive species as climate change continues. Furthermore, identifying and quantifying diet pattern seasonality can help managers identify times when sensitive species are vulnerable and plan interventions accordingly. We collected feral cat stomach contents over 18 years and examined how predation patterns varied annually and seasonally. Our results indicate seasonal variation in feral cat diet and relationships between diet and precipitation patterns, both of which have implications for mitigation of the impacts of feral cats and other invasive predators of native wildlife.

Écologie et impacts d’un prédateur introduit au sein d’un hot-spot mondial de biodiversité : le chat haret Felis catus dans l’archipel néo-calédonien

Thesis

Dec 2017

Pauline Palmas

English version : Feral cat (Felis catus) is one of the most successful and harmful invasive predator species for island biodiversity. The presence of this alien predator species generally lead to dramatic loss of native island biodiversity and represents a serious threat for numerous endemic and threatened species. Feral cats have invaded the whole New-Caledonian archipelago and all its habitats. In this study, we focused on the ecology and impacts of this invasive predator on the outstanding endemic fauna found in the different habitats of the exceptional New-Caledonia biodiversity hotspot. Feral cat diet analyses on 14 selected sites representing the 4 main natural habitats revealed a high diversified diet and high predation rates on native species particularly on squamates, flying foxes and petrels. Among the 44 vertebrates species found into the feral cat diet, 20 are IUCN red-listed threatened species. Cat movements of eleven feral cats fitted with GPS collars have been studied in a western coast Peninsula hosting an important seabird colony. Male cats showed large home ranges while female showed small home ranges. Feral cats exhibited important movements within the studied peninsula linked with the breeding cycles of seabirds. GPS data coupled with dietary informations suggested a predation that concerned both breeding adults and fledgings bird, and at a large geographic scale as some feral cats have their core home range distant to the colony (>3km). We evaluated the effects of a high level but intense cat control on this site that showed a low sustainability of feral cat culling and a rapid recolonization process. Our results are pleading for the future limitation of feral cat impacts and call to focus first abundance limitation measures on maquis mosaic and humid forest habitats This study also provided information on the spatial extent and intensity of future control measures in the special context of a large and highly invaded island. Version française : Le chat haret est l’un des prédateurs invasifs les plus dommageables pour la biodiversité insulaire. Saprésence est associée à une perte de biodiversité sur l’ensemble des îles sur lesquelles il est établi, et où ilconstitue une menace pour de nombreuses espèces de vertébrés souvent endémiques et menacés. EnNouvelle-Calédoniedes populations de chats harets sont présentes dans tous les milieux et habitats et l’étudede son écologie et de ses impacts sur la faune ont fait l’objet de ce travail de thèse. L’analyse du régimealimentaire sur 14 sites d’études représentatifs des 4 habitats majeurs a révélé un régime très diversifié et uneforte prédation sur les vertébrés natifs et notamment sur le groupe des scinques, des roussettes et des pétrels.Parmi les 44 espèces de vertébrés retrouvées dans le régime alimentaire de ce prédateur invasif, la plupartsont endémiques et 20 sont listées comme menacées sur la liste rouge mondiale de l’UICN. Le suivi desdéplacements d’une dizaine d’individus équipés de colliers GPS au niveau d’une presqu’île de la côte ouestabritant une importante colonie d’oiseaux marins, a permis de mettre en évidence de grands domaines vitauxpour les mâles, des domaines vitaux petits pour les femelles et des patrons de déplacements importants liésaux différentes étapes du cycle reproducteur des oiseaux marins. Ces éléments, couplés aux analyses derégime alimentaire suggèrent une prédation à la fois sur les adultes reproducteurs mais également sur lesjeunes oiseaux proches de l’envol, et ceci à une large échelle géographique puisque certains des chats haretsconcernés avaient le coeur de leur domaine vital situé à plus de 3km de la colonie. Une opérationexpérimentale de contrôle d’une population de chats harets a été conduite sur cette presqu’île et a montréune faible durabilité des effets de la suppression des individus sur les densités observées et une rapiderecolonisation du site. Les résultats de ce travail plaident pour la mise en place de mesures de limitation desimpacts occasionnés et permettent en particulier de cibler les habitats de maquis et forêt humide commeprioritaires en matière de limitation des abondances. Ces travaux nous éclairent également sur l’emprisespatiale et l’intensité des futures mesures de contrôle à conduire dans le contexte d’îles de grande superficieet fortement envahies.

Free-roaming dogs but not invasive mammals established in the wild endanger the flightless kagu of New Caledonia

Article

Feb 2023
BIOL CONSERV

Jörn Theuerkauf

Species on islands that evolved without mammalian predators are commonly considered naïve to these introduced animals and therefore potentially vulnerable to predation. The endemic kagu Rhynochetos jubatus, a flightless bird, is the most emblematic species of New Caledonia. As the natural top predator of the ground fauna in rainforest, it is an excellent umbrella species for conservation on mainland New Caledonia (Grande-Terre) where it lives. Here, we assess the impact of invasive mammalian species on kagu and propose specific conservation actions. We conducted intensive research over 20 years and directly measured effects of each introduced species at each stage of the kagu life span. At the population level, we assessed kagu and predator abundance at sample sites in 2001-2016 throughout Grande-Terre. At the individual level, we studied reproduction and mortality in three kagu populations in 1991-1993 and 2002-2022. We found no evidence that any of the invasive mammalian species established in the wild pose a threat to kagu. Instead, only domestic dogs, which are not established in the wild, cause significant predation and associated extreme population fluctuations. Free-roaming domestic dogs limit suitable kagu habitat to less than half of the current rainforest. Island-wide, community-based management of dogs could lead to a significant increase in kagu numbers and, as the kagu is the top predator of ground fauna, produce benefits at the ecosystem level.

Pet cat personality linked to owner‐reported predation frequency

Article

Full-text available

Jan 2023

The domestic cat, Felis catus, is one of the most popular and widespread domestic animals. Because domestic cats can reach high population densities and retain at least some tendency to hunt, their overall impact on wildlife can be severe. Domestic cats have highly variable predation rates depending on the availability of prey in their environment, their owners' practices, and individual cat characteristics. Among these characteristics, cat personality has recently been hypothesized to be an important factor contributing to variations in the hunting activity of cats. In this study, we surveyed 2508 cat owners living in France about their cats' personalities, using the Feline Five personality framework, and the frequency with which cats bring home prey. Personality traits were analyzed using factor analysis and related to predation frequency using cumulative logit models. For both birds and small mammals, cats with high levels of extraversion or low levels of neuroticism had significantly higher frequencies of prey return. Owners whose cats had low levels of agreeableness or high levels of dominance reported a significantly lower frequency of bird return. Personality differences therefore seem to contribute to the high variability in predation rates among domestic cats. We also found that the owner-reported prey return frequencies were significantly higher for cats spending more time outdoors, for non-pedigree cats, and for owners living in rural or suburban areas as opposed to urban areas. By contrast, we did not detect an effect of cat sex or age on their reported prey return rates.

An (Un)Expected Threat for a Regionally Near-Threatened Species: A Predation Case of a Persian Squirrel on an Insular Ecosystem

Article

Full-text available

Dec 2022

One of the most successful predators on island ecosystems is the domestic cat, which is considered responsible for the decline of numerous species' populations. This can be estimated by the analysis of cats' dietary habits, yet prey identification is not always possible, and thus, in cases where precise prey identification is required, one of the most accurate methods derives from observing the hunting process. However, the cryptic nature of the feral cats and the constant vigilance of the species that are preyed upon make the observation process difficult, especially when the prey has a low population density. Here, we report for the first time such a case: a feral cat that has ambushed, killed, and consumed a regionally near-threatened species, the Persian squirrel. This incidental observation happened in the squirrel's westernmost end of its distribution, the island of Lesvos, Greece. Due to the unexpectedness of the event, in the following days, we estimated both the squirrels' and cats' population density. Results showed that while the density of the squirrels is moderate, the population density of the feral cats is almost fifteen times higher. For this reason, management actions need to be taken in an effort to minimize the impacts of feral cats on the native species of the island.

Assessing the extent and public health impact of bat predation by domestic animals using data from a rabies passive surveillance program

Article

Full-text available

May 2022

Domestic animals can serve as consequential conveyors of zoonotic pathogens across wildlife-human interfaces. Still, there has been little study on how different domestic species and their behaviors influence the zoonotic risk to humans. In this study, we examined patterns of bat encounters with domestic animals that resulted in submission for testing at the rabies laboratories of the Canadian Food Inspection Agency (CFIA) during 2014–2020. Our goals were specifically to examine how the number of bats submitted and the number of rabies positive bats varied by the type of domestic animal exposure and whether domestic cats were indoor or free-roaming. The CFIA reported 6258 bat submissions for rabies testing, of which 41.5% and 8.7% had encounter histories with cats and dogs, respectively. A much smaller fraction of bat submissions (0.3%) had exposure to other domestic animals, and 49.5% had no domestic animal exposure. For the bat submissions related to cats, and where lifestyle was noted, 91.1% were associated with free-roaming cats and 8.9% with indoor cats. Model results indicated the probability of a rabies-positive bat was the highest with a history of dog association (20.2%), followed by bats with no animal exposure (16.7%), free-roaming cats (6.9%), cats with unspecified histories (6.0%) and the lowest probability associated with non-free-roaming (indoor) cats (3.8%). Although there was lower rabies prevalence in bats associated with cats compared to dogs, the 4.8 fold higher number of cat-bat interactions cumulatively leads to a greater overall rabies exposure risk to humans from any free-roaming outdoor cats. This study suggests that free-roaming owned cats may have an underappreciated role in cryptic rabies exposures in humans and as a significant predator of bats. Preventing free-roaming in cats is a cost-effective and underutilized public health recommendation for rabies prevention that also synergistically reduces the health burden of other feline-associated zoonotic diseases and promotes feline welfare and wildlife conservation.

Fire as a driver and mediator of predator-prey interactions

Article

Full-text available

Mar 2022
BIOL REV

Both fire and predators have strong influences on the population dynamics and behaviour of animals, and the effects of predators may either be strengthened or weakened by fire. However, knowledge of how fire drives or mediates predator-prey interactions is fragmented and has not been synthesised. Here, we review and synthesise knowledge of how fire influences predator and prey behaviour and interactions. We develop a conceptual model based on predator-prey theory and empirical examples to address four key questions: (i) how and why do predators respond to fire; (ii) how and why does prey vulnerability change post-fire; (iii) what mechanisms do prey use to reduce predation risk post-fire; and (iv) what are the outcomes of predator-fire interactions for prey populations? We then discuss these findings in the context of wildlife conservation and ecosystem management before outlining priorities for future research. Fire-induced changes in vegetation structure, resource availability, and animal behaviour influence predator-prey encounter rates, the amount of time prey are vulnerable during an encounter, and the conditional probability of prey death given an encounter. How a predator responds to fire depends on fire characteristics (e.g. season, severity), their hunting behaviour (ambush or pursuit predator), movement behaviour, territoriality, and intra-guild dynamics. Prey species that rely on habitat structure for avoiding predation often experience increased predation rates and lower survival in recently burnt areas. By contrast, some prey species benefit from the opening up of habitat after fire because it makes it easier to detect predators and to modify their behaviour appropriately. Reduced prey body condition after fire can increase predation risk either through impaired ability to escape predators, or increased need to forage in risky areas due to being energetically stressed. To reduce risk of predation in the post-fire environment, prey may change their habitat use, increase sheltering behaviour, change their movement behaviour, or use camouflage through cryptic colouring and background matching. Field experiments and population viability modelling show instances where fire either amplifies or does not amplify the impacts of predators on prey populations, and vice versa. In some instances, intense and sustained post-fire predation may lead to local extinctions of prey populations. Human disruption of fire regimes is impacting faunal communities, with consequences for predator and prey behaviour and population dynamics. Key areas for future research include: capturing data continuously before, during and after fires; teasing out the relative importance of changes in visibility and shelter availability in different contexts; documenting changes in acoustic and olfactory cues for both predators and prey; addressing taxonomic and geographic biases in the literature; and predicting and testing how changes in fire-regime characteristics reshape predator-prey interactions. Understanding and managing the consequences for predator-prey communities will be critical for effective ecosystem management and species conservation in this era of global change.

Tahiti Petrel Pseudobulweria rostrata rostrata and P. r. trouessarti

Chapter

Dec 2021

PhD - Conservation du gecko vert de Manapany (Phelsuma inexpectata) et du puffin du Pacifique (Ardenna pacifica) : approche multispécifique pour la conservation des falaises littorales du sud de l’île de La Réunion

Thesis

Dec 2021

Arthur Choeur

The southern coastal cliffs of Reunion Island (tropical island in the Western Indian Ocean) host a unique flora and fauna: the last populations of Manapany day gecko (Phelsuma inexpectata, an endemic reptile in critically endangered), relics of indigenous vegetation including endemic and/or threatened species (e.g.: Euphorbia viridula, Psiadia retusa, Latania lontaroides) and breeding colonies of three native seabirds (white-tailed tropicbirds, Phaethon lepturus ; brown noddies, Anous stolidus and wedge-tailed shearwaters, Ardenna pacifica). This biodiversity is threatened by habitat transformations due to invasive plants, human activities (urbanization and culture) and invasive mammals (especially cats, felis catus, and rodents). Moreover, little is known about biology and ecology of the native species, which does not allow the implementation of effective conservation strategy. Based on hand-in-hand collaboration between researchers (UMR ENTROPIE) and managers (CDL, NOI, AVE2M) working on different taxa, the aim of this thesis was to provide multispecies conservation prescriptions on cliffs study for the Manapany day gecko and the wedge-tailed shearwater. We undertook a progressive approach from describing of species conservation states through understanding threatening processes to the prescription and monitoring of management actions. Three research topics were targeted: (i) demography and reproductive biology, (ii) terrestrial habitat requirements, and (iii) impacts and management of invasive mammals (especially cats). Our results highlighted the critical conservation state of Manapany day geckos and wedge-tailed shearwaters populations. Invasive plants and mammals (especially cats) are threats to the conservation of native biodiversity. We provide several local and general conservation prescriptions, including management of invasive species, multispecies terrestrial habitat restoration and captive head-start program of Manapany day geckos. Several of these prescriptions were implemented during this thesis (invasive species management and captive breeding program) and monitored as part of active adaptive management approach. This multispecies study at the interface between research and management must be continued and supported by a strong federating regulatory tool as a National Nature Reserve (NNR). Keywords: Ardenna pacifica, biological invasions, captive head-start program, Capture-Mark-Recapture, cat control, cat tracking, conservation biology, Felis catus, habitat selection, multispecies management, Phelsuma inexpectata, population dynamics, Population Viability Analyses, Reunion Island, Spatial Mark-Resight, tropical island

Make flying-fox hunting sustainable again: Comparing expected demographic effectiveness and hunters’ acceptance of more restrictive regulations

Article

Oct 2021

Hunting is a major threat to many species of wildlife. However, managing hunting systems to ensure their sustainability requires a thorough demographic knowledge about the impact of hunting. Here we develop a framework integrating ecological, modelling and sociological data to achieve a sustainability assessment of flying-fox hunting in New Caledonia and assess the relative merits of alternative management policies. Using age-specific stochastic population models, we found that the current annual hunting rate [5.5−8.5%] is likely to lead to a severe decline (− 79%) of Pteropus populations over the next 30 years. However, a majority of hunters surveyed (60%) were willing to soften their practices, offering an opportunity for adaptive management. Recurrent temporary hunting ban (at least 1 year out of 2) in combination with protected areas (≥ 25%) appears as the most effective and most accepted management option. Our integrative approach appears to be a promising method for ensuring that traditional hunting systems can remain sustainable in a rapidly changing world.

The ecological costs and benefits of a feral cat poison‐baiting programme for protection of reintroduced populations of the western quoll and brushtail possum

Article

Aug 2021

Conservation practitioners implement management interventions for the protection of threatened species, but the benefits are rarely measured. We investigated the efficacy of aerial poison baiting for feral cats, a species identified as a threat to reintroduced populations of two Australian mammals. We measured individual survival, short‐term changes in activity and longer term population trajectories in cats and reintroduced western quolls and brushtail possums before and after annual baiting events. Between 87% and 100% of radiocollared feral cats that remained in the baited area died from poisoning in 2017, 2018 and 2019. Camera detection rates significantly declined after each event (40–77%), and the proportion of cameras occupied remained lower after baiting commenced (20–60% before vs. <20% after). Cat decline on cameras was significantly higher in areas with low rabbit abundance, suggesting controlling alternative prey would improve baiting success. Importantly, none of 37 radiocollared quolls died from poisoning despite pre‐baiting trials determining that they were the most common species removing baits (26%). We detected no negative impact of baiting on the quoll and possum populations but could not demonstrate a significant net benefit. Trapping data suggested no change in annual quoll survival after baiting despite a slight increase in survival of radiocollared quolls. Quoll detection rates on camera did not significantly decline after each baiting event. A decline in the last two years of monitoring was possibly due to drought conditions. Approximately 10% of radiocollared possums died from poisoning after the first baiting event, but trapping and camera detections suggested a stable or increasing population. Poison baiting successfully reduced cat abundance, and there was no measurable negative effect on populations of reintroduced species. Long‐term monitoring through a range of seasonal conditions is required to determine the net benefit of predator control for reintroduced populations where paired impact and control sites are impractical. We tested aerial cat baiting for the protection of reintroduced western quolls and brushtail possums. Baiting successfully reduced cat abundance and had no adverse effect on quoll and possum populations.

Status of Gould’s Petrel Pterodroma leucoptera caledonica in New Caledonia: distribution, breeding biology, threats and conservation

Article

Jun 2021

Pterodroma leucoptera caledonica is a subspecies of Gould’s Petrel endemic to New Caledonia. Its distribution, abundance and breeding biology are poorly known. Extensive surveys of New Caledonia between 1994 and 2014 located only two breeding colonies, and a further likely, but still unconfirmed; the total estimated size of the population could be of the order of 5000–7000 breeding pairs. Nesting burrows were situated either near streams or on slopes near ridges. The breeding phenology of caledonica was similar to that of the Australian leucoptera, but with a breeding calendar that lagged that of leucoptera by 2–4 weeks depending on year and breeding parameter. Breeding success was low, with evidence of a high level of predation of eggs, chicks and adults by rats, pigs and cats. Pigs also destroyed nesting burrows. Permanent bait stations installed to control rats at one colony appeared successful, but the control of pigs and cats is much more problematic. If, as expected, the level of predation observed at one colony extends across all breeding colonies, population decline is inevitable and extinction likely in the long term. With no populations of P. l. caledonica on predator-free offshore islands, translocation to such sites may be evaluated to safeguard this subspecies. In the meantime, we recommend that the global status of Gould’s Petrel Pterodroma leucoptera be upgraded from Vulnerable to Endangered.

Zoonotic Risk: One More Good Reason Why Cats Should Be Kept Away from Bats

Article

Full-text available

Mar 2021

Bats are often unfairly depicted as the direct culprit in the current COVID-19 pandemic, yet the real causes of this and other zoonotic spillover events should be sought in the human impact on the environment, including the spread of domestic animals. Here, we discuss bat predation by cats as a phenomenon bringing about zoonotic risks and illustrate cases of observed, suspected or hypothesized pathogen transmission from bats to cats, certainly or likely following predation episodes. In addition to well-known cases of bat rabies, we review other diseases that affect humans and might eventually reach them through cats that prey on bats. We also examine the potential transmission of SARS-CoV-2, the causal agent of COVID-19, from domestic cats to bats, which, although unlikely, might generate a novel wildlife reservoir in these mammals, and identify research and management directions to achieve more effective risk assessment, mitigation or prevention. Overall, not only does bat killing by cats represent a potentially serious threat to biodiversity conservation, but it also bears zoonotic implications that can no longer be neglected.

Levels of genetic differentiation and gene flow between four populations of the Scaly-naped Pigeon, Patagioenas squamosa : implications for conservation

Article

Full-text available

Feb 2021
STUD NEOTROP FAUNA E

Island-endemic columbid species are particularly vulnerable to environmental degradation, extreme climatic events, and interactions with exotic species. The situation might be even more critical in the case of exploited species, where legal hunting and poaching can severely affect population dynamics. Here we document for the first time the genetic structure of the Scaly-naped Pigeon, Patagioenas squamosa, a Caribbean-endemic columbid species of cynegetic interest, over a large part of its range. Using both mitochondrial DNA and nuclear markers (microsatellites), we investigated gene flow, genetic diversity, and genetic structure among four islands populations originating from Puerto-Rico, Guadeloupe, Martinique and Barbados. We found evidence for a significant genetic differentiation only between the Barbados and the three other populations, consistent with the fact that the Barbados population originated from a few captive individuals escaped from a rooftop aviary in Bridgetown about 100 years ago. Given the absence of genetic differentiation between Puerto Rico and the French Antilles, our results suggest that, apart from Barbados, the species may mainly consist of a single large, homogeneous population. We discuss the relevance of our findings in relation to management and conservation issues.

Drivers and facilitators of hunting behaviour in domestic cats and options for management

Article

Full-text available

Dec 2020

en • Domestic cats Felis catus are distinct from other domesticated animals because their phenotype and genotype are relatively unchanged. While they live with people as pets or pest controllers, they retain capacity for survival independent of human support and readily persist as feral animals. Most cats retain some propensity to express hunting behaviours, even if hunting is not required for nutrition. In some settings, depredation by cats is a threat to biodiversity conservation, leading to attempts to mitigate their impacts. • We characterise drivers and facilitators of the hunting behaviour of domestic cats: evolutionary origins, diet, life history, personality and environment. Hunting is driven particularly by evolutionary constraints and associated physiological and nutritional requirements. Proximate causes of variation in hunting behaviours relate to prey availability, husbandry and degree of domestication, while early life history and personality play further roles. • We review cat management approaches in terms of effectiveness, feasibility and welfare. Amongst lethal, large‐scale methods of population control, poisoning is most frequently used in cat eradications from islands. Because poisoning is challenged on welfare grounds, euthanasia is used at smaller scales and in inhabited, mainland settings. Non‐lethal approaches, primarily surgical sterilisation, are favoured by cat advocates but entail challenging logistics and scale. In attempts to inhibit predation of wild species by pet cats, owners restrict outdoor access and use collar‐mounted devices, including bells, sonic devices, collar covers and bibs. Other individual‐level interventions, such as dietary and behavioural enrichment, some of which may improve cat welfare, have potential, but effects on hunting remain untested. • Understanding and managing the hunting behaviour of cats are complex challenges. We highlight drivers and facilitators of this behaviour, representing starting points for formulating solutions that might be acceptable to cat owners and wider groups of people who value cat welfare, while also being effective for wildlife conservation. RIASSUNTO IN ITALIANO it • I gatti domestici Felis catus si distinguono dagli altri animali domestici poiché i loro fenotipo e genotipo sono rimasti relativamente invariati. Nonostante vivano con le persone come animali domestici o vengano impiegati per il controllo dei roditori infestanti, i gatti domestici hanno mantenuto la capacità di sopravvivere indipendentemente dal supporto umano, e possono facilmente persistere come animali ferali (rinselvatichiti). La maggior parte dei gatti ha mantenuto una certa propensione alla caccia, nonostante questa non sia necessaria a sopperire a esigenze nutrizionali. In determinati ecosistemi la massiccia predazione da parte dei gatti rappresenta una minaccia per la conservazione della biodiversità, determinando quindi la necessità di adottare soluzioni per mitigare i possibili effetti negativi. • In questo studio vengono caratterizzati i fattori chiave che inducono i gatti domestici a cacciare, nonché quelli che ne facilitano l’espressione: le origini evolutive, il regime alimentare, le esperienze fatte nel corso della vita, la personalità e l’ambiente. Il comportamento di caccia è primariamente determinato da vincoli evolutivi e da fabbisogni fisiologici e nutrizionali ad esso associati. Le cause prossime coinvolte nelle variazioni di tale comportamento sono legate alla disponibilità di prede, dal metodo di allevamento del gatto e dal suo grado di addomesticamento; le esperienze fatte nei primi mesi di vita e la personalità del gatto ricoprono anch’essi un ruolo importante. • Abbiamo revisionato i diversi approcci impiegati nella gestione dei gatti in termini di efficacia, fattibilità e benessere. Tra i metodi letali impiegati su larga scala nel controllo di popolazione, l’avvelenamento è risultato essere quello più frequentemente utilizzato per l’eradicazione dei gatti dalle isole. Poiché l’avvelenamento è contestato per motivi legati al benessere, su scala più piccola e in posti abitati sulla terraferma viene preferita l’eutanasia. Gli approcci non letali, in particolare la sterilizzazione chirurgica, sono favoriti dai sostenitori dei diritti dei gatti, ma implicano complicazioni sul piano logistico e risultano comunque essere di portata più limitata. Nel tentativo di inibire la predazione dei gatti domestici sulle specie selvatiche, i proprietari ne limitano l’accesso all’esterno e utilizzano dispositivi che si attaccano ai collari, come campanelle, dispositivi sonori, copri collari colorati e bavagli ingombranti. Altri interventi a livello individuale come, ad esempio, l’arricchimento alimentare e quello comportamentale hanno un potenziale (alcuni potrebbero incrementare il benessere del gatto stesso), ma gli effetti sul comportamento di caccia non sono stati ancora testati. • La comprensione e la gestione del comportamento di caccia dei gatti rappresentano delle sfide complesse. Il presente lavoro evidenzia i fattori che guidano e quelli che facilitano tale comportamento, che rappresentano i punti di partenza per formulare soluzioni che potrebbero essere accettate dai proprietari dei gatti e da tutte le persone che ne valorizzano il benessere, e che al contempo siano efficaci nel salvaguardare gli animali selvatici.

Trophic ecology of an introduced top predator (Felis catus) on a small African oceanic islet (Santa Luzia, Cabo Verde Islands)

Article

Oct 2020
AFR J ECOL

en Studies on feral cat diet offer important ecological information and are the first step towards determining their impact upon endangered species. However, in comparing seasonal changes in diet with seasonal prey availability, the scarce amount of research into oceanic islands worldwide must be considered when deciding if a specific population is actually affected by cat predation. Cat diet was analysed on Santa Luzia (Cabo Verde Islands) since this invasive predator is considered one of the main threats to native endangered species that require conservation measures. These previous studies were carried out in different seasons, providing contrasting results, skinks being more preyed upon in the rainy season and mice in the driest periods. To check these different results, we focussed on how cat diet varied seasonally in response to changes in prey abundance. Saurians were the most important prey group, followed by mice, invertebrates and birds. No seasonal differences were, however, observed in the different prey groups consumed, saurians being the main prey in both seasons. All cases reflected their respective abundances. Results corroborate the generalist and opportunistic trophic ecology of feral cats, providing important information to assess their impact on prey populations and design future eradication programmes. Résumé fr Les études sur le régime alimentaire des chats sauvages offrent des informations écologiques importantes et constituent la première étape vers la détermination de leur impact sur les espèces menacées. Cependant, le faible nombre de recherches portant sur la comparaison entre les changements saisonniers du régime alimentaire et la disponibilité saisonnière des proies réalisées sur les îles océaniques du monde entier doit être pris en compte pour décider si une population spécifique est réellement affectée par la prédation des chats. Le régime alimentaire des chats a été analysé à Santa Luzia (îles du Cap Vert) car ce prédateur envahissant est considéré comme l'une des principales menaces pesant sur les espèces indigènes en voie de disparition nécessitant des mesures de conservation. Ces études antérieures ont été menées à différentes saisons, fournissant des résultats contrastés, les scinques étant les proies principales pendant la saison des pluies et les souris pendant les périodes les plus sèches. Pour vérifier ces différents résultats, nous nous sommes concentrés sur la façon dont l'alimentation des chats variait selon les saisons en réponse aux variations en termes d'abondance des proies. Les sauriens constituaient le groupe de proies le plus important, suivis des souris, des invertébrés et des oiseaux. Aucune différence saisonnière n'a cependant été observée au sein des différents groupes de proies consommés, les sauriens étant la principale proie pendant les deux saisons. Tous les cas reflétaient leurs abondances respectives. Les résultats corroborent l'écologie trophique généraliste et opportuniste des chats sauvages, tout fournissant des informations importantes pour évaluer leur impact sur les populations de proies et concevoir de futurs programmes d'éradication.

Feral cat abundance, density and activity in tropical island rainforests

Article

Full-text available

Oct 2020
WILDLIFE RES

Context. Introduced predators, especially cats, are a major cause of extinction globally. Accordingly, an extensive body of literature has focussed on the ecology and management of feral cats in continental and island systems alike. However, geographic and climatic gaps remain, with few studies focusing on rainforests or tropical islands of the south-western Pacific. Aims. We aimed to estimate cat densities and elucidate activity patterns of cats and sympatric birds and mammals in tropical island rainforests. We hypothesised that cat activity would be most influenced by the activity of introduced rodents and ground-dwelling birds that are predominant prey on islands. Methods. We used camera traps to detect feral cats, pigs, rodents and birds on four tropical islands in the south-western Pacific. We used spatial capture–recapture models to estimate the abundance and density of feral cats. Relative abundance indices, and temporal overlaps in activity were calculated for feral cats, pigs, rodents, and birds. We used a generalised linear model to test for the influence of pig, rodent, and bird abundance on feral cat abundance. Key results. The species most commonly detected by our camera traps was feral cat, with estimated densities between 0.31 and 2.65 individuals km�2. Pigs and introduced rodents were the second- and third-most commonly detected fauna respectively. Cat activity was bimodal, with peaks in the hours before dawn and after dusk. Cat abundance varied with site and the abundance of rodents. Conclusions. Feral cats are abundant in the tropical rainforests of our study islands, where one bird and two mammal species are now presumed extinct. Introduced rodents possibly amplify the abundance and impacts of feral cats at our sites. Peak cat activity following dusk did not clearly overlap with other species detected by our camera traps. We postulate cats may be partly focussed on hunting frogs during this period. Implications. Cats are likely to be a major threat to the highly endemic fauna of our study region. Management of feral cats will benefit from further consideration of introduced prey such as rodents, and their role in hyperpredation. Island archipelagos offer suitable opportunities to experimentally test predator–prey dynamics involving feral cats.

Integrating traditional knowledge, science and conservation in the search for undescribed mammals on Malaita, Solomon Islands

Article

Full-text available

Dec 2020

Basic knowledge of species diversity and distributions underpins the study of island biogeography and is fundamental for conservation planning. In Solomon Islands, new mammals continue to be described and several lineages are yet to be documented from large islands where, presumably, they should occur. On Malaita and Makira, no giant rats (Solomys or Uromys), or monkey-faced bats (Pteralopex) have been documented by scientists, but traditional knowledge suggests they exist. In East Kwaio, Malaita, we combined traditional knowledge and scientific methods to survey mammals and search for these taxa. Camera traps, mist nets, spotlight surveys, echolocation call recorders, rat traps and active searches were used to produce an inventory of the island’s mammals. No Solomys, Uromys or Pteralopex were captured. However, detailed accounts suggest that giant rats and monkey-faced bats were present as recently as 1996 and 2002 respectively. Moreover, we consider the presence of gnawed Canarium nuts an indicator that giant rats still persist. The human population of Malaita is dense, hunting pressure appears high, feral cats are common, and logging is rapidly reducing primary forests. A notable feature of this work has been the commitment towards collaboration and upskilling landowners in mammal survey techniques. This collaboration has helped fuel a growing conservation movement on Malaita and led to the designation of three large conservation areas. Gathering evidence for the existence of undescribed mammals on Malaita is paramount for reducing further extinctions in Melanesia. Continued support for skilled community members in East Kwaio will be key to collecting this evidence.

Plastic ingestion by seabirds in New Caledonia, South Pacific

Article

Mar 2020
MAR POLLUT BULL

The accumulation of plastic pollutants in marine environments has many adverse effects on wildlife. In particular, marine predators are often exposed to accidental plastic ingestion, that may negatively affect survival due to the concentration of debris in the digestive tract. Among the species most vulnerable to plastic ingestion, seabirds are of major interest for conservation because of their wide foraging areas, long generation time and extended lifespan. We analysed stomach contents of 90 seabird specimens from 12 different species collected in New Caledonia to assess the local prevalence of plastic ingestion. Overall, we found plastic debris in 14.4% of sampled individuals, exclusively in procellariids: Gould's Petrel (41.2%, highest incidence), Tahiti Petrel (33.3%) and Wedge-tailed Shearwater (7.7%). To our knowledge, this study is the first characterization of plastic ingestion in seabirds from New Caledonia and our results show an overall lower ingestion prevalence compared to other assessments in the tropical Pacific.

Monitoring hunted species of cultural significance: Estimates of trends, population sizes and harvesting rates of flying-fox (Pteropus sp.) in New Caledonia

Article

Full-text available

Dec 2019
PLOS ONE

Assessing population trends and their underlying factors is critical to propose efficient conservation actions. This assessment can be particularly challenging when dealing with highly mobile, shy and nocturnal animals such as flying-foxes. Here we investigated the dynamics of hunted populations of Pteropus ornatus and P. tonganus in the Northern Province of New Caledonia. First, an ethno-ecological survey involving 219 local experts identified 494 flying-fox roosts. Current status was assessed for 379 of them, among which 125 were no longer occupied, representing a loss of 33% over ca. 40 years. Second, species-specific counts conducted at 35 roosts, and a sample of animals killed by hunters, revealed that the endemic species, P. ornatus, was dominant (68.5%). Between 2010 and 2016, 30 roosts were counted annually during the pre-parturition period. Roosts size averaged 1,425 ± 2,151 individuals (N = 180 counts) and showed high among-year variations (roost-specific CV = 37–162%). If we recorded significant inter-annual variation, we did not detect a significant decline over the 7-yr period, although one roost went possibly extinct. Population size of the two species combined was estimated at 338,000−859,000 individuals distributed over ca. 400 roosts in the Northern Province. Flying-foxes are popular game species and constitute traditional food for all communities of New Caledonia. Annual bags derived from a food survey allowed us to estimate harvesting rates at 5–14%. Such a level of harvesting for species with a ‘slow’ demography, the occurrence of poaching and illegal trade, suggest the current species use might not be sustainable and further investigations are critically needed.

Predation on endangered species by human-subsidized domestic cats on Tokunoshima Island

Article

Full-text available

Nov 2019

It is important to unravel how invasive species impact native ecosystems in order to control them effectively. The presence of abundant exotic prey promotes population growth of invasive predators, thereby enhancing the predation pressure on native prey (hyper-predation). Not only the exotic prey but also feeding by humans is likely to cause “hyper-predation”. However, the contribution of artificial resources to this was underestimated in previous studies. Here, we combined fecal and stable isotope analyses to reveal short- and long-term food habits of free-ranging cats on Tokunoshima Island. Although 20.1% of the feral cat feces contained evidence of forest-living species, stable isotope analysis suggested that the cats were mostly dependent on artificial resources. In addition, a general linear model analysis showed that their diet was strongly correlated with landscape variables. These results indicate that the invasive free-ranging cats are aided by anthropogenic feeding, and they move from the human habituated area to natural areas with high biodiversity. These findings suggest the possibility of human feeding indirectly accelerates the effect of cat predation, and call for a further study on their demography. Cat management mainly involves trapping, but our findings show that educating local residents to stop feeding free-ranging cats and keeping pet cats indoors are also important.

A resource-efficient procedure to improve planning of invasive cat management on inhabited islets

Article

Full-text available

May 2019
BIOL INVASIONS

Cats (Felis silvestris catus) are one of the most pernicious invasive species on islands, being responsible for the decline and extinction of many vertebrate taxa. Eradications programs are a powerful tool to fight against cat impacts on islands, but their implementation requires planning and design to prevent failure. In that sense, gathering data on cat habitat use, abundance and trophic interactions provides key information to effectively design management actions. The present contribution presents a simple resource-efficient methodology using cat feces to assess cat distribution, density and trophic ecology on an inhabited islet. This information is essential in order to effectively organize trapping efforts and minimize subsequent impacts of other species if a control or eradication campaign is undertaken. Additionally, our research effort evaluated the potential influence of coastal and anthropic resources on cat diet, which can also provide useful information for planning aside management actions. Cat distribution on our model islet, La Graciosa, was ‘clumped’, presenting higher densities in anthropic areas (villages and farms). The invasive house mouse and the European rabbit were the main prey items, although native invertebrates, reptiles and birds were also consumed. Cats on La Graciosa ingested a large quantity of garbage, which was negatively correlated with distance from human settlements. Considering the low time and resource requirements of this methodology, and the useful basic ecological information it provides, it can be employed to make optimal management planning decisions for small inhabited islands where cat control or eradication programs are being considered.

Kuniesaurus albiauris, a New Genus and Species of Scincid Lizard from the Île des Pins, New Caledonia, with Comments on the Diversity and Affinities of the Region’s Lizard Fauna

Article

Jan 2019
PAC SCI

A new genus and species of skink, Kuniesaurus albiauris, is here described from the Île des Pins off southern New Caledonia. This new taxon possesses a unique suite of morphological apomorphies (scalation) that does not allow it to be placed in any existing Australasian eugongylid genus. It is known only from a single area in dense coastal forest on limestone, on the main island of the Île des Pins. The species area of occupancy is restricted, and the habitat occupied under threat from the spread of the highly invasive Little Red Fire Ant Wasmannia auropunctata. These factors place this new skink at a level of risk sufficient for it to be listed as Critically Endangered under IUCN Red List criteria. The affinities of the lizard fauna of the Île des Pins with respect to that present on southern New Caledonia are also discussed, most notably the absence from the Île des Pins of taxa typically restricted to ultramafic surfaces.

Quelle stratégie de recherche pour une meilleure conservation de la biodiversité terrestre dans les îles tropicales ultramarines françaises ?

Article

Full-text available

Jun 2018

The 11 French Overseas tropical island territories, located in three oceans (Atlantic, Indian and Pacific), harbored a high species and habitat diversity on small terrestrial areas. Indeed, these islands comprise 70% of the 17,947 endemic plant and animal species known in France on an area of only 4 % of the French nation. This “mega-biological” diversity hold France responsible for the study and conservation of this biodiversity at the international level. Moreover, this unique natural heritage is highly threatened by local and global anthropogenic changes (e.g. loss and degradation of natural habitats, biological invasions, climate change) with exacerbated impacts in the more vulnerable island ecosystems, and with record numbers of extinct of endangered endemic species. Those challenges justify that particular efforts in research and conservation sciences should be conducted on both species and habitats. Research programs dedicated to island terrestrial biodiversity (including wetlands), with more concerted efforts between research scientists, managers and local island communities, and between territories sharing the same challenges, should lead to common strategies and demonstrate the relevance of knowledge issues as well as the importance of these overseas tropical island territories at the national, regional and international scales.

Nest-site selection and its influence on breeding success in a poorly-known and declining seabird: The Tahiti petrel Pseudobulweria rostrata

Article

Full-text available

Apr 2022
PLOS ONE

The Tahiti petrel (Pseudobulweria rostrata) is a rare and declining seabird whose breeding biology and nest-site selection are poorly known. Nest-site selection is critical to seabird population fitness, and understanding the factors driving it is essential for designing effective conservation measures. Here, we measured several variables (topographical, physical and environmental) to characterize Tahiti petrel nesting habitats and burrows (i.e., width, height, depth and type: rocky cavity, dug into the soil or under a root) on Nemou Island in New Caledonia. The data were clustered using the HCPC (Hierarchical Clustering on Principal Component) method to identify principal habitat groups. This method was combined with logistic regressions to examine the influence of the variables on nest-site selection and breeding success. Our results showed that nest-site selection is linked to habitat groups (a combination of substrate and vegetation data), slope, orientation and soil depth, while breeding success is only influenced by nest characteristics (i.e., burrow type and width). Tahiti petrels prefer to nest on steep slopes in mature forests with rocky substrate and deep soil. Burrows were scatterred in small sub-colonies or isolated pairs, suggesting that nest-site selection depends on habitat quality rather than conspecific density. The study also revealed that breeding success is lower in rocky cavities and increases in burrows with wide entrances. Our nest-site selection survey is the first for the genus Pseudobulweria, and provides critical information for designing effective conservation programs in New Caledonia and the Pacific.

Einfluss von Hauskatzen auf die Biodiversität

Book

Full-text available

Aug 2021

The impact of domestic cats on vertebrates is now known globally - they are a major risk for endangered and threatened species. Hybridization of domestic and wild cats must also not go unnoticed, so there are already studies across Europe with differentiated results on this. Especially in the last decades, however, the domestic cat has become an increasingly popular pet throughout the western world, and its numbers continue to increase, which can lead to unnaturally high densities in settlements, for example. To summarize the current state of knowledge on this topic we supplemented the previously published report of Hackländer et al. (2014) with current data and literature. In particular, the topics of hybridization, potential management measures, legal framework and food analyses, which specifically address the impact of domestic cats on biodiversity, were considered in an expanded manner. The research revealed the need for action on the topic, which should not be underestimated, and the necessity of both the acceptance of personal responsibility and the consistent implementation of given political frameworks. The paper appeared in the BOKU Berichte zur Wildtierforschung und Wildbewirtschaftung and is available online. Translated with www.DeepL.com/Translator (free version)

Sensibilité des populations de roussettes (Mégachiroptères, Pteropodidae) aux prélèvements cynégétiques et aux prédateurs introduits : une approche éco-démographique en Nouvelle Calédonie

Thesis

Full-text available

Jul 2021

Malik OEDIN

Habitat degradation, invasive species and overexploitation are currently the three main threats to biodiversity. Here we present a study on the population status of two sympatric flying fox species, Pteropus ornatus (endemic) and P. tonganus (native), and the impact of hunting and predation by the feral cat Felis catus in New Caledonia. The study of flying fox roost occupancy in the North Province shows a 33% disapearance in 40 years. The flying fox population on Grande Terre is estimated at about 735,000 individuals (of both species) and the annual hunting rate at 7%. Integrated stochastic modelling of this population suggests that current harvesting levels could lead to a decline of up to 80% in the next 30 years. Temporary hunting ban and/or protected areas appear, in addition to being combinable, to be the most acceptable and effective management options for hunters. An analysis of the data available worldwide shows that all forms of cats prey on bats in all habitats and that this threat is probably largely underestimated. Finally, initial results suggest that flying fox predation by feral cats in New Caledonia is of the same order of magnitude as hunting. This study proposes a framework for assessing the sustainability of hunting game species in an integrated adaptive management approach, taking into account other threat factors such as invasive species.

New Caledonia : a very old Darwinian island ?

Article

Full-text available

Jan 2008

New Caledonia has generally been considered a continental island, the biota of which largely dates back to Gondwanan times owing to its geological origin and the presence of phylogenetic relicts. This view is contradicted by geological evidence indicating long Palaeocene and Eocene submersions and by recent biogeographic and phylogenetic studies, with molecular or geophysical dating placing the biota no older than the Oligocene. Phylogenetic relicts do not provide conclusive information in this respect, as their presence cannot be explained by simple hypotheses but requires assumption of many ad hoc extinction events. The implication of this new scenario is that all the New Caledonian biota colonized the island since 37 Ma Local richness can be explained by local radiation and adaptation after colonization but also by many dispersal events, often repeated within the same groups of organisms. Local microendemism is another remarkable feature of the biota. It seems to be related to recent speciation mediated by climate, orography, soil type and perhaps unbalanced biotic interactions created by colonization disharmonies. New Caledonia must be considered as a very old Darwinian island, a concept that offers many more fascinating opportunities of study.

Impacts and management of feral cats Felis catus in Australia

Article

Full-text available

Nov 2016
MAMMAL REV

Feral cats are among the most damaging invasive species worldwide, and are implicated in many extinctions, especially in Australia, New Zealand and other islands. Understanding and reducing their impacts is a global conservation priority. We review knowledge about the impacts and management of feral cats in Australia, and identify priorities for research and management. In Australia, the most well understood and significant impact of feral cats is predation on threatened mammals. Other impacts include predation on other vertebrates, resource competition, and disease transmission, but knowledge of these impacts remains limited. Lethal control is the most common form of management, particularly via specifically designed poison baits. Non-lethal techniques include the management of fire, grazing, food, and trophic cascades. Managing interactions between these processes is key to success. Given limitations on the efficacy of feral cat management, conservation of threatened mammals has required the establishment of insurance populations on predator-free islands and in fenced mainland enclosures. Research and management priorities are to: prevent feral cats from driving threatened species to extinction; assess the efficacy of new management tools; trial options for control via ecosystem management; and increase the potential for native fauna to coexist with feral cats.

Invasive predators and global biodiversity loss

Article

Full-text available

Sep 2016
P NATL ACAD SCI USA

Significance Invasive mammalian predators are arguably the most damaging group of alien animal species for global biodiversity. Thirty species of invasive predator are implicated in the extinction or endangerment of 738 vertebrate species—collectively contributing to 58% of all bird, mammal, and reptile extinctions. Cats, rodents, dogs, and pigs have the most pervasive impacts, and endemic island faunas are most vulnerable to invasive predators. That most impacted species are insular indicates that management of invasive predators on islands should be a global conservation priority. Understanding and mitigating the impact of invasive mammalian predators is essential for reducing the rate of global biodiversity loss.

How did the ultramafic soils shape the flora of the New Caledonian hotspot?

Article

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Jun 2016
PLANT SOIL

Background New Caledonia is renowned as one of the world’s most significant biodiversity hotpots. The nutrient-deficiency and cations imbalances of ultramafic soils, which cover a third of the island, harbor a disproportionally high proportion of the plant diversity and endemism of New Caledonia. Scope This review explores how ultramafic soils have influenced the exceptional endemism and richness of New Caledonia trough the concomitant occurrences of habitat patchiness, climatic instability, environmental gradient, and edaphic heterogeneity of ultramafic soils. We focus on the unique ‘maquis’ vegetation where selective pressures by nutrient deficiency and trace element surplus are at their acme. We aim to synthesize our current understanding of diversification and speciation of lineages that have been phylogenetically studied to date. Conclusions Fragmentation of the peridotite mantle in isolated massifs, and as such spatial heterogeneity of ultramafic soils types, appear to promote plant endemism and speciation. Repeated independent dispersal events of pre-adapted species and persistence of paleo-endemic lineages have contributed to the phylogenetic diversity and the endemism of the ultramafic flora. Finally, historical climatic instability has caused shifts of rain forest species in refugia thereby favoring the extension of maquis species.

Stop Jumping the Gun: A Call for Evidence‐Based Invasive Predator Management

Article

Full-text available

Apr 2016

Invasive mammalian predators are major drivers of species extinctions globally. To protect native prey, lethal control is often used with the aim of reducing or exterminating invasive predator populations. The efficacy of this practice, however, is often not considered despite multiple practical and ecological factors that can limit success. Here, we summarize contemporary knowledge regarding the use and challenges of both lethal control and alternative approaches for reducing invasive predator impacts. As the prevailing management approach, we outline four key issues that can compromise the effectiveness of lethal control: release of herbivore and mesopredator populations, disruption of predator social systems, compensatory predator immigration, and ethical concerns. We then discuss the relative merits and limitations of four alternative approaches that may enhance conservation practitioner's ability to effectively manage invasive predators: top-predator conservation or reintroduction, maintaining habitat complexity, exclusion fencing, and behavioral and evolutionary ecology. Considerable uncertainty remains regarding the effectiveness of management approaches in different environmental contexts. We propose that the deficiencies and uncertainties outlined here can be addressed through a combination of adaptive management, expert elicitation, and cost-benefit analyses. Improved management of invasive predators requires greater consideration and assessment of the full range of management approaches available.

Invasive mammal eradication on islands results in substantial conservation gains

Article

Full-text available

Mar 2016

More than US$21 billion is spent annually on biodiversity conservation. Despite their importance for preventing or slowing extinctions and preserving biodiversity, conservation interventions are rarely assessed systematically for their global impact. Islands house a disproportionately higher amount of biodiversity compared with mainlands, much of which is highly threatened with extinction. Indeed, island species make up nearly two-thirds of recent extinctions. Islands therefore are critical targets of conservation. We used an extensive literature and database review paired with expert interviews to estimate the global benefits of an increasingly used conservation action to stem biodiversity loss: eradication of invasive mammals on islands. We found 236 native terrestrial insular faunal species (596 populations) that benefitted through positive demographic and/or distributional responses from 251 eradications of invasive mammals on 181 islands. Seven native species (eight populations) were negatively impacted by invasive mammal eradication. Four threatened species had their International Union for the Conservation of Nature (IUCN) Red List extinction-risk categories reduced as a direct result of invasive mammal eradication, and no species moved to a higher extinction-risk category. We predict that 107 highly threatened birds, mammals, and reptiles on the IUCN Red List—6% of all these highly threatened species—likely have benefitted from invasive mammal eradications on islands. Because monitoring of eradication outcomes is sporadic and limited, the impacts of global eradications are likely greater than we report here. Our results highlight the importance of invasive mammal eradication on islands for protecting the world’s most imperiled fauna.

Importance of lethal control of invasive predators for island conservation

Article

Full-text available

Dec 2015
CONSERV BIOL

We support the call of Wallach et al. (2015a) for a compassionate approach to conservation, and agree that any lethal control must be justified by a high probability of conservation gains and supported by relevant stakeholders. We believe that lethal control of invasive predators is justified when it will reverse the negative impacts of predators introduced by humans on native species and ecosystems, and when the extent of that predation endangers the survival of entire populations or species. Globally a few key introduced predator species are having disproportionately large effects on island ecosystems and their constituent species (e.g. Towns et al. 2006; Medina et al. 2011). Where invasive predators are killed to achieve conservation goals, we believe this can come from compassion for all of the ecosystem, its species, the individuals being protected, and the invasive animals themselves. This view is well supported by literature and policies relating to the role of animal welfare, animal rights, and environmental ethics in pest control programmes (e.g. Gunn 2007; Dunlevy et al. 2011). This article is protected by copyright. All rights reserved.

The global islands invasive vertebrate eradication database: a tool to improve and facilitate restoration of island ecosystems, in island invasives: eradication and management

Article

Full-text available

Jan 2011

Bats in the Anthropocene: Conservation of Bats in a Changing World

Book

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Jan 2016

This book focuses on central themes related to the conservation of bats. It details their response to land-use change and management practices, intensified urbanization and roost disturbance and loss. Increasing interactions between humans and bats as a result of hunting, disease relationships, occupation of human dwellings, and conflict over fruit crops are explored in depth. Finally, contributors highlight the roles that taxonomy, conservation networks and conservation psychology have to play in conserving this imperilled but vital taxon. With over 1300 species, bats are the second largest order of mammals, yet as the Anthropocene dawns, bat populations around the world are in decline. Greater understanding of the anthropogenic drivers of this decline and exploration of possible mitigation measures are urgently needed if we are to retain global bat diversity in the coming decades. This book brings together teams of international experts to provide a global review of current understanding and recommend directions for future research and mitigation.

Improving morphological diet studies with molecular ecology: An application for invasive mammal predation on island birds

Article

Full-text available

Jan 2015
BIOL CONSERV

On islands, invasive predators, particularly feral cats and rats, are key drivers of bird population decline and extinction. Diet studies can be used to assess predator impacts on prey populations. Here we first evaluated the resolution of morphological identification (Class to Species) of bird remains in cat and rat diet studies. We also analysed the effect of predator size/type (cat vs rat) and sample type (faecal vs stomach contents) on the taxonomic level of bird identification. We found that difficulty in identifying bird remains significantly increased with taxonomic resolution (from Class to Species) for both predators. Bird identification was more accurate in cat than in rat diets and no sample-type effect was detected in cat diets. Second, we developed a set of molecular resources (DNA sequence database and bird-specific primer pairs) to detect and identify bird DNA. We tested and validated primer pairs’ taxonomic coverage and specificity using in silico and in vitro analyses. The performances of morphological and molecular methods were then compared in a case study of cat and rat diet samples collected on Niau Atoll (French Polynesia). Our results highlight the efficiency of the molecular method in both detection and high-resolution identification of birds in predator diet samples. As robust qualitative and quantitative diet analyses are required to accurately assess predator impacts on prey populations, we recommend combining morphological and molecular methods to maximise bird detection, identification and quantification, especially when rare or threatened birds are at stake. http://authors.elsevier.com/a/1S8mg_9CgPYQs

Opportunistic observation of predation of Loggerhead turtle hatchlings by feral cats on Dirk Hartog Island, Western Australia

Article

Full-text available

Sep 2010
J Roy Soc West Aust

This note reports the opportunistic observation of predation of Loggerhead turtle hatchlings at Turtle Bay on Dirk Hartog Island, Western Australia. Data were collected on the movement patterns of three feral cats, fitted with GPS data-logger/radio-telemetry collars in the vicinity of turtle nests. This data as well as field observations demonstrate a distinct patrolling of Turtle Bay and surrounding areas. Furthermore, predation of turtle hatchlings by cats was confirmed by their presence in the stomach contents of one of the cats.

Review of feral cat eradications on islands

Chapter

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Jan 2011

4. La faune des milieux sur roches ultramafiques

Chapter

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Dec 2010

The New Caledonian leopard skink Lacertoides pardalis (Reptilia: Scincidae) : a review of the species' morphology, distribution, behavior and conservation

Article

Full-text available

Oct 2014

Lacertoides pardalis est un scinque endémique de grande taille, caractérisé par de petites écailles sur tout le corps. Cette espèce a été décrite pour la première fois en 1997, à partir de 2 spécimens en provenance d’un unique site de récolte, dans l’extrême sud de la Grande Terre. Depuis la description originale, il y a une dizaine d’année, plusieurs individus ont été capturés dans la même région (des juvéniles mais également des spécimens adultes de grande taille). Ces captures permettent de fournir des informations sur la biologie et l’écologie de l’espèce, en particulier, une reproduction vivipare et un régime alimentaire généraliste, reposant sur de la prédation d’invertébrés mais également sur d’autres espèces de reptiles et de façon plus inattendue avec une frugivorie importante. L. pardalis pourrait jouer un rôle important pour la dissémination de certaines espèces du maquis, voire de lisières forestières. Ces nouvelles captures ont permis d’élargir significativement l’aire de répartition connue de l’espèce, qui est considéré vulnérable (VU) selon les critères de la liste rouge de l’IUCN. Cependant, la région d’où est connue L. pardalis a subi de profondes transformation au cours de la dernière décennie, en raison du développement de projet minier sur le plateau de Goro. Des études complémentaires restent à mener pour conserver cette espèce originale et unique des habitats de maquis rocheux du sud de la Nouvelle-Calédonie.

Island specificities matter: cat diet differs significantly between islands of a major breeding archipelago for a vulnerable endemic seabird

Article

Full-text available

Oct 2015
BIOL INVASIONS

Domestic cats are one of the most widespread predators on islands worldwide and are responsible for numerous reductions and extinctions of species on islands. The three main islands of the Hyères Archipelago house one of the largest colonies of the Mediterranean endemic Yelkouan shearwater Puffinus yelkouan that has recently been up-listed by the IUCN to ‘vulnerable’. The main objectives of this study were to assess the diet of cats and to study the effect of cat predation on Yelkouan shearwater populations at the archipelago scale. The diet of cats was studied using scat analyses according to years and seasons for each island. Simultaneously, Yelkouan shearwater breeding success was monitored during a period of 8 years on Port-Cros and Porquerolles, and 3 years on Le Levant. Descriptive analyses and GLM were used to compare data gathered on each island. At the archipelago scale, cats preyed strongly upon introduced mammals and shearwaters. Surprisingly, large differences appeared in cats’ diet according to the island considered. The Yelkouan shearwater was the primary prey of cats on Le Levant, but secondary on Port-Cros and Porquerolles. Cat predation was mainly concentrated during the shearwater prospecting period, when birds arrive at the colonies and look for a mate (if they are not already paired) and a burrow before breeding. Consequently cat impact was low on shearwater breeding success. However, this study demonstrates that the cat management conducted on Port-Cros was positive for fledging success. The successful cat eradication on Port-Cros supports the need to continue working for Yelkouan shearwater conservation with Le Levant as a priority, because this is where the colonies are largest and predation on Yelkouan shearwaters is very high.

The Importance of Islands for the Protection of Biological and Linguistic Diversity

Article

Full-text available

Jun 2015
BIOSCIENCE

Islands make up 5.3% of Earth's land area yet maintain an estimated 19% of bird species, 17% of rodents, 17% of flowering plants, and 27% of human languages. Species diversity is disproportionately threatened on islands in relation to the islands’ proportion of both global land area and species, with 61% of all extinct species and 37% of all critically endangered species confined to islands. Languages are disproportionately threatened on islands in relation to land area with 11% of extinct languages and 25% of critically endangered languages on islands. Islands are a priority area for integrated conservation efforts because they have 14 times greater density of critically endangered terrestrial species and 6 times greater density of critically endangered languages than continental areas. Invasive species and habitat loss are the largest threats to island terrestrial species diversity. Proven management actions can reduce these threats, benefiting both local peoples and species diversity on islands.

Ongoing unraveling of a continental fauna: Decline and extinction of Australian mammals since European settlement

Article

Full-text available

Feb 2015

Significance The island continent of Australia harbors much of the world’s most distinctive biodiversity, but this review describes an extent of recent and ongoing loss of its mammal fauna that is exceptionally high and appreciably greater than previously recognized. The causes of loss are dissimilar to those responsible for most biodiversity decline elsewhere in the world.

Trophic roles of black rats and seabird impacts on tropical islands: Mesopredator release or hyperpredation?

Article

Full-text available

Jan 2015
BIOL CONSERV

A continental-scale analysis of feral cat diet in Australia

Article

Full-text available

May 2015
J BIOGEOGR

Reducing the impacts of feral cats (Felis catus) is a priority for conservation managers across the globe, and success in achieving this aim requires a detailed understanding of the species’ ecology across a broad spectrum of climatic and environmental conditions. We reviewed the diet of the feral cat across Australia and on Australian territorial islands, seeking to identify biogeographical patterns in dietary composition and diversity, and use the results to consider how feral cats may best be managed. Australia and its territorial islands. Using 49 published and unpublished data sets, we modelled trophic diversity and the consumption of eight food groups against latitude, longitude, mean temperature, precipitation, environmental productivity and climate-habitat regions. We recorded 400 vertebrate species that feral cats feed on or kill in Australia, including 28 IUCN Red List species. We found evidence of continental-scale prey-switching from rabbits to small mammals, previously recorded only at the local scale. The consumption of arthropods, reptiles, rabbits, rodents and medium-sized native mammals varied with different combinations of latitude, longitude, mean annual precipitation, temperature and environmental productivity. The frequency of rodents and dasyurids in cats’ diets increased as rabbit consumption decreased. The feral cat is an opportunistic, generalist carnivore that consumes a diverse suite of vertebrate prey across Australia. It uses a facultative feeding strategy, feeding mainly on rabbits when they are available, but switching to other food groups when they are not. Control programmes aimed at culling rabbits could potentially decrease the availability of a preferred food source for cats and then lead to greater predation pressure on native mammals. The interplay between cat diet and prey species diversity at a continental scale is complex, and thus cat management is likely to be necessary and most effective at the local landscape level.

Eradication of feral cats from large islands: An assessment of the effort required for success

Article

Full-text available

Jul 2014
NEW ZEAL J ECOL

Feral cats (Felis catus) are predators and competitors of native species on many islands and are therefore the target of control efforts. Cat eradication has been achieved on 83 islands worldwide. Six of these successes have been from large islands (over 2000 ha) and have reported sufficient data to examine how the eradication was achieved through combinations of aerial and ground-based poison baiting, fumigation in rabbit burrows used by cats, cage and leghold trapping, day and night shooting, and hunting with dogs. No common sequence of tactics was deployed although leghold traps were used in the latter phases of most projects. It took a mean reported effort of 543 ± 341 person-days per 1000 ha of island over 5.2 ± 1.6 years to completely remove cats and validate success from the six islands. These precedents may assist in planning future proposals to eradicate cats from other large islands.

Les peuplements néo-calédoniens de vertébrés: invasions, disparitions

Chapter

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Jan 2006

Seabird conservation status, threats and priority actions: A global assessment

Article

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Mar 2012
BIRD CONSERV INT

We review the conservation status of, and threats to, all 346 species of seabirds, based on BirdLife International’s data and assessments for the 2010 IUCN Red List. We show that overall, seabirds are more threatened than other comparable groups of birds and that their status has deteriorated faster over recent decades. The principal current threats at sea are posed by commercial fisheries (through competition and mortality on fishing gear) and pollution, whereas on land, alien invasive predators, habitat degradation and human disturbance are the main threats. Direct exploitation remains a problem for some species both at sea and ashore. The priority actions needed involve: a) formal and effective site protection, especially for Important Bird Area (IBA) breeding sites and for marine IBA feeding and aggregation sites, as part of national, regional and global networks of Marine Protected Areas; b) removal of invasive, especially predatory, alien species (a list of priority sites is provided), as part of habitat and species recovery initiatives; and c) reduction of bycatch to negligible levels, as part of comprehensive implementation of ecosystem approaches to fisheries. The main knowledge gaps and research priorities relate to the three topics above but new work is needed on impacts of aquaculture, energy generation operations and climate change (especially effects on the distribution of prey species and rise in sea level). We summarise the relevant national and international jurisdictional responsibilities, especially in relation to endemic and globally threatened species.

Earliest evidence for commensal process of cat domestication

Article

Full-text available

Dec 2013
P NATL ACAD SCI USA

Significance Domestic cats are one of the most popular pets worldwide, but little is known about their domestication. This study of cats living 5,300 y ago at the agricultural village of Quanhucun, China provides the earliest known evidence for mutualistic relationships between people and cats. Isotopic data demonstrate that humans, rodents, and the cats ate substantial amounts of millet-based foods, with cats preying on grain-eating animals. One cat was old and one ate less meat and more millet than others, suggesting it scavenged leftovers or was fed. Diverse data demonstrate rodent threats to stored grain, indicating cats were advantageous to farmers, whereas food in villages was attractive to cats. These findings provide evidence for commensal processes of cat domestication.

Feral Cats And Biodiversity Conservation: The Urgent Prioritization Of Island Management

Article

Full-text available

Oct 2013
BIOSCIENCE

A great part of the Earth's biodiversity occurs on islands, to which humans have brought a legion of invasive species that have caused population declines and even extinctions. The domestic cat is one of the most damaging species introduced to islands, being a primary extinction driver for at least 33 insular endemic vertebrates. Here, we examine the role of feral cats in the context of the island biodiversity crisis, by combining data from reviews of trophic studies, species conservation status reports, and eradication campaigns. The integration of these reviews permits us to identify priority islands where feral cat eradications are likely to be feasible and where cats are predicted to cause the next vertebrate extinctions. Funding agencies and global conservation organizations can use these results to prioritize scarce conservation funds, and national and regional natural resource management agencies can rank their islands in need of feral cat eradication within a global context.

Connectivity and invasive species management: Towards an integrated landscape approach

Article

Full-text available

Oct 2013
BIOL INVASIONS

Invasive plants and animals are a major cause of global biodiversity loss. Invasive Species Management (ISM) helps conserve localized populations and ecosystems, but rarely have its potential benefits been explored at the landscape scale. We explore how ISM can enhance landscape connectivity, and how its incorporation into conservation planning algorithms could help design optimal reserve networks. Conversely, conservation planning and connectivity modelling can optimize targeting of ISM, achieving benefits for a wider range of taxa and ecological processes, without the need for additional resources. Empirical research must investigate the spatial pattern of benefits from ISM, and when to target priority conservation sites or the areas (matrix) between them. By bolstering populations within—and increasing connectivity between—focal patches, ISM should move beyond conserving individual sites to creating functionally connected networks of conservation areas.

Cat predation of short-tailed bats (Mystacina tuberculata rhyocobia) in Rangataua Forest, Mount Ruapehu, Central North Island, New Zealand

Article

Full-text available

Sep 2012
NEW ZEAL J ZOOL

Cats (Felis catus) are known predators of New Zealand bats, although all records to date have been from domestic cats thought to have caught foraging bats. We outline the first evidence of predation of short-tailed bats (Mystacina tuberculata rhyocobia) at a roost tree. A total of 156 individual bat wings (78 pairs) and 22 intact bodies were found at the base of two colonial roost trees in Rangataua Forest on the southern slopes of Mount Ruapehu, Central North Island in New Zealand, over a period of 7 days. Assuming a pair of wings belonged to one individual, at least 102 bats were killed by a male cat caught in a live trap at the base of one roost tree. No more deaths were recorded after its capture.

Late-Holocene bats of Mé Auré Cave, New Caledonia: Evidence of human consumption and a new species record from the recent past

Article

Full-text available

Jan 2012

Flying-foxes and smaller, insectivorous bats, as well as birds, frogs, lizards, rodents and humans, are among Holocene vertebrate remains recovered from a cave near Mé Auré on the central southwestern coast of Grande Terre, the main island of New Caledonia, southwest Pacific. New Caledonia is one of the world’s most critically endangered biodiversity hotspots whose native terrestrial mammals consist of nine bat species, six of which are endemic. The Mé Auré Cave deposit accumulated over a period of some 3000 years, from before colonization of the area by people to the present. In the deposit’s upper levels, bat remains approximate the modern New Caledonian fauna – with the notable exception of the first record of a leaf-nosed bat from these islands – and probably represent bats that lived and died in the cave as well as those brought in as prey by barn owls. In the lowest levels, only flying-foxes are represented, their corroded teeth and other evidence suggesting they were cooked and eaten by people. Our data indicate that at least one insectivorous bat species has become extinct during the last 250 years in New Caledonia. Alternatively, it is possible that this leaf-nosed bat continues to be part of the threatened extant New Caledonian bat fauna but has yet to be recorded by modern faunal surveys.

Multiple Kagu Rhynochetos jubatus deaths caused by dog attacks at a high-altitude study site on Pic Ningua, New Caledonia

Article

Full-text available

Dec 1996
BIRD CONSERV INT

Dog predation has been cited as an important factor in the decline of the threatened Kagu of New Caledonia but direct evidence of predation was restricted to single kills. Here we report the first documented case of multiple Kagu deaths caused by dogs, which occurred at our 200 ha, high-altitude (800-1,300 m) study site on Pic Ningua. The deaths were discovered because we were radio-tracking Kagus there as part of our behavioural study on the birds. In 1993 we found 20 Kagus either dead (15) or wounded (5; one survived) from dog attacks in four distinct episodes over a 14-week period from late April to early August. Two other birds whose older remains were found also probably died from dog attacks. Of the 22 birds 18 wore radio transmitters; the four non-radio-tracked birds were found by chance. Dogs errant from a nearby tribal village were strongly implicated in carrying out most, if not all, of the attacks. They climbed around 1,000 m in altitude to reach the study site and attacked birds there on repeat visits to the site. The apparent recent disappearance of Kagus in forest neighbouring the study site suggests the dogs caused the deaths of most of the birds on the peak. Dog predation is probably an ongoing problem for the Kagu and the attacks at Pic Ningua are probably not an isolated incident. Protecting birds outside Riviere Bleue Park from dogs will require: (1) establishment of additional intensively managed reserves; (2) continuing education of the public and administrators about the need for Kagu protection and associated dog control; (3) involvement of tribal communities in Kagu conservation; and (4) enforcement of dog control laws. The events at Pic Ningua demonstrate the necessity for additional and non-connected reserves to safeguard against catastrophes and increase the probability of long-term Kagu persistence in the wild.

Species invasions and extinction: The future of native biodiversity on islands

Article

Full-text available

Jan 2008

Predation by exotic species has caused the extinction of many native animal species on islands, whereas competition from exotic plants has caused few native plant extinctions. Exotic plant addi- tion to islands is highly nonrandom, with an almost perfect 1 to 1 match between the number of naturalized and native plant species on oceanic islands. Here, we evaluate several alternative implica- tions of these findings. Does the consistency of increase in plant richness across islands imply that a saturation point in species richness has been reached? If not, should we expect total plant richness to continue to increase as new species are added? Finally, is the rarity of native plant extinctions to date a misleading measure of the impact of past invasions, one that hides an extinction debt that will be paid in the future? By analyzing historical records, we show that the number of naturalized plant species has increased linearly over time on many individual islands. Further, the mean ratio of naturalized to native plant species across islands has changed steadily for nearly two centuries. These patterns suggest that many more species will become naturalized on islands in the future. We also discuss how dynamics of invasion bear upon alternative saturation scenarios and the implications these scenarios have for the future retention or extinction of native plant species. Finally, we identify invasion-motivated research gaps (propagule pressure, time-lags to extinction, abundance shifts, and loss of area) that can aid in forecasting extinction and in developing a more comprehensive theory of species extinctions. between extinction and colonization. At the saturation point, the addition of new colonizing species results in the local extinction of a like number of previously established species. We refer to this as ''extinction-based saturation,'' which is consistent with Island Biogeography Theory (IBT) (6, 7). Second, the total number of species in a place could be maintained by suppression of colonization. A saturation point is reached if the invasion of new species is inhibited by species already present. We refer to this as ''colonization-based saturation,'' which is consistent with the resistance to invasion in niche-based models of species diversity, such as Stochastic Niche Theory (SNT), where the total number of species in a place is determined by how finely resources can be partitioned among species (9). These alternative pathways for species saturation have very different implications for the impact of invading species on native plant extinctions. Extinction-based saturation (like IBT) explicitly predicts species turnover, i.e., change in species com- position, with the addition of species to islands (6, 7). Therefore, once a saturation point has been reached, the continued addition of exotic species should result in the extinction of native species, and the rate of extinction increases as the rate of colonization increases. If this holds true for islands, then we may eventually have dramatic increases in the number of native plant extinc- tions—particularly if exotics continue to be added in large numbers. In contrast, colonization-based saturation (like SNT) explicitly predicts that the addition of exotic species will become progressively less likely to occur as species richness increases (10). Colonization-based saturation (like SNT) also predicts that existing species should benefit from a priority effect that makes them unlikely to be displaced by incoming species—as long as invading species are more or less equivalent to native species in their efficiency in using resources (10). If this holds true on islands, then we should expect the rate of naturalization of exotic species to diminish dramatically and few currently established species (both native and exotic) to be at risk of extinction in the future. These are two very distinct views of the future, and distinguishing among these and other alternatives is important. Doing so will help us to advance our basic understanding of ecological and evolutionary theory while simultaneously advanc- ing our understanding of a pressing applied issue, namely the future of plant diversity on islands worldwide. Here, we evaluate the role of species invasions on the extinc- tion of native species. We begin by examining the International Union for Conservation of Nature database for patterns of extinction in plants and terrestrial vertebrates that have occurred This paper results from the Arthur M. Sackler Colloquium of the National Academy of Sciences, ''In the Light of Evolution II: Biodiversity and Extinction,'' held December 6-8,

The endemic Mediterranean Yelkouan Shearwater Puffinus yelkouan: distribution, threats and a plea for more data

Article

Full-text available

Apr 2008
ORYX

The endemic Mediterranean yelkouan shearwater Puffinus yelkouan, elevated to the rank of species in 2002, is poorly monitored and studied. Despite this lack of data and the susceptibility of closely related species to threats at breeding sites and foraging areas, the yelkouan shearwater is currently considered to be at low risk of extinction. This review, based on published documents, personal communications with scientists and our own observations, summarizes available data on range, population size and trends, and on threats to the species' existence. Breeding sites range from the Marseille islands (France) to Bulgarian islands in the Black Sea but many are not confirmed. The estimated global population is 11,355-54,524 pairs but most censuses are probably overestimates and the global population could be only a few thousand breeding pairs. There is evidence of a population decline and susceptibility to introduced mammals, particularly feral cats Felis catus and ship rats Rattus rattus, and to accidental bycatch in fishing gear. We highlight the lack of accurate and regular censuses of the species, and the alarming situation suggested by the little data available. We recommend that the yelkouan shearwater be categorized as Near Threatened on the IUCN Red List, encourage collaborative work to clarify its status, and make a plea for more data on the species’ demography and ecology, and for the evaluation of terrestrial and marine threats.

The Global Islands Invasive Vertebrate Eradication Database: A tool to improve and facilitate restoration of island ecosystems

Conference Paper

Full-text available

Jan 2011

Islands are important for the conservation of biodiversity because they house 20% of terrestrial plant and vertebrate species, have suffered 64% of IUCN-listed extinctions and have 45% of IUCN-listed critically endangered species. Yet islands make up only about five percent of the earth’s surface. The main cause of extinction and endangerment to biodiversity on islands is the presence of invasive vertebrates. Fortunately, many future extinctions can be prevented by eradicating invasive vertebrates from islands. To assess the current state of this conservation tool, we are compiling a global database of terrestrial vertebrate eradications from islands, including successes and failures. To date, in the Global Islands Invasives Vertebrate Eradication Database we have documented approximately 950 island eradication attempts involving 28 species of invasive vertebrates in 12 families. These are preliminary data and will be updated and checked for accuracy as part of the Island Invasives: Eradication and Management conference, Auckland 2010. Most eradication attempts have been of rodents (textgreater350) and bovid ungulates (textgreater160). Moderate numbers of eradication attempts have been of cats (textgreater90), suid ungulates (textgreater55), and rabbits (textgreater45). Most projects have been on islands smaller than 500 ha (68%) and in temperate climates (72%). Targeting eradications on larger and more tropical islands would lead to the protection of more biodiversity. To this end, our vision is to maintain an accurate, web-accessible, regularly updated database that can be used to promote and improve the protection of island ecosystems by eradicating invasive vertebrates.

Feeding Ecology of a Feral Cat Population on a Small Mediterranean Island

Article

Full-text available

Aug 2007

Domestic cats (Felis catus) have been introduced on many islands in the world and are responsible for much damage to native insular faunas. The worldwide success and spread of this opportunistic predator is generally associated with its trophic adaptability. We examined the diet of a long-established feral cat population on a small Mediterranean island through the analysis of 1,219 scats collected during a 4-year period. Our results confirm that feral cats are generalist predators, able to feed on a wide range of prey. However, only a few prey species formed the major part of its diet. Two introduced mammals and a Mediterranean endemic seabird provided 93% of the yearly biomass consumed by cats (ship rats, 70%; wild rabbits, 7%; and yelkouan shearwaters, 6%). Ship rats remained by far the staple prey for cats throughout the year, but the diet of feral cats was more diversified in spring and early summer, frequently including insects, reptiles, and migrant birds. Endemic yelkouan shearwaters were preyed upon most frequently in autumn and winter, that is, during the shearwaters' prelaying period. Because rats provide the majority of the food of cats, they could help to maintain or inflate this alien predator population with deleterious consequences to the endemic shearwater. A cat eradication campaign would help protect the population of shearwaters on this island.

The impact of the feral cat (Felis catus) on the native fauna of Aldabra atoll, Seychelles

Article

Jan 1990
REV ECOL-TERRE VIE

Wendy Seabrook

Feral cats (Felis catus) have had devastating effects on island ecosystems throughout the world. The history, distribution and ecology of the feral cat on Aldabra Atoll (a World Heritage Site) is summarized, and used with information from studies of feral cats elsewhere, to assess their impact on native fauna. Despite virtually all of the Aldabran fauna being potentially vulnerable to cat predation, no native species have (apparently) become extinct. Cats are however having an impact, the most dramatic being that all the sea-birds and many land birds restrict their nesting to the few cat-free sites, and that the flightless White-throated rail (Dryolimnas cuvieri aldabranus) survives on two islands where cat populations have yet to become established. These impacts are sufficient to recommend that the cat population should be eradicated, but in practice this would be impossible using the currently available techniques suitable for use on Aldabra.

Programme R-Mines : impact des espèces invasives sur les reptiles des massifs miniers : rapport final

Technical Report

Jan 2015

R: A Language and Environment for Statistical Computing

Book

Jan 2015

Core R Team

The domestic cat: the biology of its behavior

Article

Jan 1988

The 14 contributions, 9 abstracted separately, which explore the behaviour and ecology of Felis catus (= Felis silvestris catus) are arranged in 4 major sections (development of young cats, social life, predatory behaviour, cats and people), together with an introduction and a postscript. -P.J.Jarvis

Old but not ancient: Coalescent species tree of New Caledonian geckos reveals recent post-inundation diversification

Article

Feb 2016
J BIOGEOGR

New Caledonia is a remnant of the land mass Tasmantis that harbours high levels of endemism. Two primary hypotheses have been proposed for the origin of such endemic lineages; the first suggests a vicariant origin arising from the sundering of eastern Gondwana in the Cretaceous. The second posits more recent dispersal and colonization. We use concatenated and coalescent time-calibrated phylogenies to test whether New Caledonian diplodactylid geckos diversified steadily following an ancient vicariance event or experienced an early burst of diversification followed by a decline in net diversification after long-distance dispersal. New Caledonia, Gondwana. Phylogenetic relationships were elucidated from a multilocus DNA data set. Divergence times were inferred using relaxed clock Bayesian methods on the concatenated data set and in a multispecies coalescent framework using *beast. In order to elucidate patterns of diversification for the New Caledonian clade we tested models of diversification using laser and ddd. The divergence of the New Caledonian clade from its Australian sister clade occurred well after Gondwanan fragmentation, and the age of the crown clade is younger than the proposed drowning period of the island. Diversification analyses strongly suggest that the group experienced an early burst of diversification, which has slowed towards the present. We demonstrate that the species-rich diplodactylid geckos endemic to New Caledonia are of recent origin and that the diversification of the clade is consistent with the expectations of a recent radiation. Diversification in this clade does not conform to a constant-rate model, but rather experienced an initial burst followed by a decline in net diversification. This pattern is consistent with a decline in diversification as ecological niche space was filled. Our results add to the growing body of evidence that recent adaptive radiations have contributed to the remarkable endemism of New Caledonia.

Third complement to the list of the birds of New Caledonia

Article

Jan 2009

Over the last 3 years, eleven species of birds not previously known on the island have been observed, increasing the previous number (204) of species/subspecies recorded in New Caledonia to 214 taxa (the introduced Anas aucklandica has disappeared in the wild and is removed from the list). Most of the new records are marine birds: Light-mantled Albatross Pboebetria palpebrata, Buller's Albatross Thalassarche bulleri, Buller's Shearwater Puffinus bulieri, White-faced Storm-Petrel Pelagodroma marina, Black-bellied Storm Petrel Fregetta tropica, Brown Skua Sfercorarius antarcticus. Two coastal the White-winged Tern Chlidonias leucopterus, the Pied Heron Egretta picata and three terrestrial new visitors the Black Kite Milvus migrans, the Dusky Woodswallow Artamus cyanopterus and the Polynesian Triller Lalage maculosa have been recorded. One species, the Little Black Cormorant Phalacrocorax sulcirostris, previously classified as an Australian regular migrant became a local breeder. Among native birds, the 2008 and 2009 IUCN revisions modified the status of seven threatened species, 2 being downgraded and 5 upgraded. The situation of the Crow Honeyeater Gymonyza aubryana now classified critically endangered (CR) is of particular concern.

The potential for biodiversity offsetting to fund invasive species eradications on Islands

Article

Oct 2015
CONSERV BIOL

Balancing development and biodiversity conservation presents significant challenges. One approach, biodiversity offsetting, represents “measurable conservation outcomes resulting from actions designed to compensate for significant residual adverse biodiversity impacts resulting from project development”, and is a final step in a mitigation hierarchy following steps of avoidance, minimization, rehabilitation and restoration (Business and Biodiversity Offsets Programme 2012). Norton and Warburton (2015) use the main islands of New Zealand as a case study to provide a well-reasoned assessment of the potential for biodiversity offsetting to fund invasive alien species (IAS) control. They identify seven key conditions that must be met to satisfy the approach: “be technically possible to reduce invasive species to levels that enhance native biodiversity; be affordable; be sufficiently large to compensate for the impact; be adaptable to accommodate new strategic and tactical developments while not compromising biodiversity outcomes; acknowledge uncertainties associated with managing pests; be based on an explicit risk assessment that identifies the cost of not achieving target outcomes; and include financial mechanisms to provide for in-perpetuity funding”.This article is protected by copyright. All rights reserved

Niche and movement models identify corridors of introduced feral cats infringing ecologically sensitive areas in New Zealand

Article

Sep 2015
BIOL CONSERV

The mitigation of the impact caused by introduced mammalian predators is a priority for conservation managers. Reducing predator population numbers is the most realistic strategy in mainland areas or large islands, and could be a feasible alternative to pest eradication. However, the success of control campaigns depends not only on removal of resident individuals, but also on managing reinvasions facilitated by connectivity with surrounding source populations. We combined niche analysis and fine-scale movement analyses of feral cats (Felis silvestris catus) to identify least-cost corridors from sources surrounding controlled areas of the ecologically sensitive area of Tasman Valley and Aoraki/Mt. Cook National Park, New Zealand. Intensive control of exotic predators has been executed during the last ten years in this area, where they pose a threat to native species such as endangered ground-nesting birds. Species distribution models revealed that cat distribution in the region was limited by its main prey, the European rabbit, and to mid-elevation (~ 1600 m) areas. Using GPS-tracking data and step-selection functions, we found that cats moved in an optimized fashion suggesting a maximum energy gain associated with high rabbit presence, while avoiding landscape obstacles such as rugged terrain. Connectivity between the high probability of cat presence in source and destination locations (in the control area) was facilitated by 1–3 corridors between valleys and multiple paths within valleys. Identification of least-cost paths, rooted in ecological and behavioral mechanisms underlying space use, can identify realistic putative corridors for focused implementation of control measures for introduced species in ecologically sensitive areas.

A new species of lizard in the genus Caledoniscincus (Reptilia: Scincidae) from southern New Caledonia and a review of Caledoniscincus atropunctatus (Roux)

Article

Aug 2013

A new species of skink, Caledoniscincus notialis sp. nov., is described from the ultramafic ranges in southern New Caledonia. It is most similar to, and has previously been referred to Caledoniscincus atropunctatus (Roux), a species with a widespread distribution throughout the Grand Terre and Loyalty Islands. The new species is distinct genetically from all other Caledoniscincus and can be distinguished by a unique pattern of dorsal coloration in males. Its range extends over much of the extensive ultramafic block in the south of the island, including the Goro Plateau and the mountain ranges at the southern edge of the Chaine Centrale north to Mt. Humboldt. It occurs mainly in humid forest habitat, much of which is now present only as isolated fragments in southern New Caledonia. Its preference for a habitat that has undergone a significant reduction in area of extent in a region under pressure from a range of anthropogenic threats suggests this new species is of conservation concern, and could be ranked as Vulnerable under IUCN listing. The genetic relationships of a redefined Caledoniscincus atropunctatus identifies two major subgroups, one located mainly in the northern and central-east regions of Grand Terre and the other in the southern and central-west regions and also including the population on the Loyalty Islands.

A New Member of the Bavayia cyclura Species Group (Reptilia: Squamata: Diplodactylidae) from the Southern Ranges of New Caledonia

Article

Apr 2012

Feral cats threaten the outstanding endemic fauna of the New Caledonia biodiversity hotspot

Abstract

No full-text available