Wild rabbits in Australia developed genetic resistance to the myxoma virus, which was introduced ... more Wild rabbits in Australia developed genetic resistance to the myxoma virus, which was introduced as a biological control agent. However, little is known about the rate at which this evolutionary change occurred. We collated data from challenge trials that estimated rabbit resistance to myxomatosis in Australia and expressed resistance on a continuous scale, enabling trends in its development to be assessed over 45 years up to 1995. Resistance initially increased rapidly, followed by a plateau lasting ten years, before a second rapid increase occurred associated with the introduction of European rabbit fleas as myxoma virus vectors. By contrast, in the United Kingdom, where rabbit flea vectors were already present when the myxoma virus initially spread, resistance developed more slowly. No estimates of rabbit resistance to myxomatosis have been made for almost 30 years, despite other highly lethal rabbit pathogens becoming established worldwide. Continued testing of wild-caught rabbi...
European rabbit fleas were released among Australian wild rabbits in the late 1960s to supplement... more European rabbit fleas were released among Australian wild rabbits in the late 1960s to supplement mosquitoes as vectors of myxoma virus. Data from study sites across southern Australia in the 1960s and 1970s are reviewed to discern common elements of flea-borne myxomatosis epizootics and a simple model is proposed to explain how virus virulence and food quality interact to determine rabbit abundance. Low, stable populations of rabbits implied that, despite virus attenuation and increased rabbit disease resistance, flea-borne myxomatosis was extremely important in controlling rabbit populations. Despite the enhancement of myxomatosis, livestock producers benefitted little from the additional pasture because marketing difficulties were not conducive to industry growth. Native wildlife likely benefitted, nonetheless.
In 1984, an unknown disease was reported in the People' s Republic of China among Angora rabbits ... more In 1984, an unknown disease was reported in the People' s Republic of China among Angora rabbits which had been recently imported from the German Democratic Republic (28). Within a few months, the disease had spread widely through commercial rabbitries in the People' s Republic of China (59) and had also reached the Republic of Korea (41). Investigators in the People' s Republic of China rapidly developed an inactivated vaccine, using livers of infected rabbits, to control the disease (25). Nevertheless, a new unknown disease, initially named 'Malattia-X', appeared in domestic rabbits in Italy in 1986 (9), leading to the deaths of millions of domestic rabbits. This new disease soon appeared in other countries in Europe (34), and in 1987-1988, a link was established with the viral haemorrhagic disease of rabbits in the People' s Republic of China. Research on this new disease was rapidly initiated in
The rabbit flea Caenopsylla laptevi ibera occurs in arid environments of central and eastern Spai... more The rabbit flea Caenopsylla laptevi ibera occurs in arid environments of central and eastern Spain. Although the fleas breed during the coolest, most humid part of the year, the larvae survive and grow in sand at only 50-60 % relative humidity. At 22°C and 80 % relative humidity eggs hatch in six days and the cocoon stage is reached 10-1 1 days after hatching. Female fleas emerge from pupation at about 1 7 days after cocoon spinning; males emerge a little later at a mean of 20 days. Adult fleas are mainly found on the host Oryctolagus cuniculus. Measurements of burrow microclimate confirmed that in southeastern Spain burrow humidity was adequate for the development of C. /. ibera larvae over most of the year. However, breeding may be restricted for at least part of the year, as the larvae of C. I. ibera apparently cannot complete development at 25 °C or above. In the laboratory, fleas can enter a prolonged quiescent period while in the cocoon. This is possibly a facultative, pre-pupal diapause and the likely mechanism that accounts for the disappearance of adult fleas from the field by spring and their reappearance each autumn.
This paper challenges conclusions of Caughley et al. (1980) that the abundance of red kangaroos (... more This paper challenges conclusions of Caughley et al. (1980) that the abundance of red kangaroos (Macropus rufus) in western New South Wales is solely due to lack of dingoes (Canis lupus dingo), and vice versa for neighbouring South Australia. A Dingo Barrier Fence divides the two different ecological systems, which have sheep in New South Wales and cattle in South Australia. This paper re-examines in particular whether there is an environmental gradient across the Fence that was dismissed by Caughley et al. This paper concludes to the contrary, that there is a strong environmental gradient. Our aerial surveys demonstrate significantly that habitats favouring red kangaroos are prevalent in New South Wales today, but are very scarce or absent in South Australian landscapes. Aerial surveys were used in both studies, but designs differed. Caughley et al. flew at right angles across the Fence on paths 28 km apart. Flights would have crossed the south-westerly streamlines rarely. Our flig...
ELISA techniques developed for the veterinary diagnosis of Rabbit Haemorrhagic Disease (RHD) in d... more ELISA techniques developed for the veterinary diagnosis of Rabbit Haemorrhagic Disease (RHD) in domestic rabbits were used for studying the epidemiology of RHD in Australian wild rabbits. The combination of ELISA techniques that distinguished IgA, IgG and IgM antibody responses and a longitudinal data set, mainly based on capture-mark-recapture of rabbits, provided a reliable basis for interpreting serology and set the criteria used to classify rabbits' immunological status. Importantly, young with maternal antibodies, immune rabbits and rabbits apparently re-exposed to RHD were readily separated. Three outbreaks of RHD occurred in 1996–7. The timing of RHD outbreaks was mainly driven by recruitment of young rabbits that generally contracted RHD after they lost their maternally derived immunity. Young that lost maternal antibodies in summer were not immediately infected, apparently because transmission of RHDV slows at that time, but contracted RHD in the autumn when conditions ...
This review considers the history of the discovery of the rabbit haemorrhagic disease virus (RHDV... more This review considers the history of the discovery of the rabbit haemorrhagic disease virus (RHDV) and its spread throughout the world in domestic and wild rabbits, which led eventually to its deliberate release into Australia and New Zealand for the control of a major pest, the introduced wild rabbit. The physical and genetic structure of RHDV is now well understood, and its pathogenic effects are also well known. The epidemiology of rabbit haemorrhagic disease (RHD) has been clearly documented in the field in European countries, Australia and New Zealand. Since its initial spread through largely naïve populations of wild rabbits it has established a pattern of mainly annual epizootics in most areas. The timing of epizootics is dependent on climatic variables that determine when rabbits reproduce and the appearance of new, susceptible rabbits in the population. The activity of RHDV is also influenced by climatic extremes that presumably affect its persistence and the behaviour of i...
Context European rabbits evolved in Spain and Portugal and are adapted to winter-rainfall Mediter... more Context European rabbits evolved in Spain and Portugal and are adapted to winter-rainfall Mediterranean habitats. On introduction into Australia in 1859, wild rabbits quickly colonised similar habitats across the southern two-thirds of the continent. However, over the past 40 years, they have spread further into monsoonal savanna habitats in northern Queensland. Aims To explain this, we considered adaptive responses of wild rabbits to hot conditions, particularly potential mechanisms for reducing the heat load of lactation, which has been identified as a likely limiting factor. Methods We analysed data from captive wild rabbits to identify mechanisms that could potentially reduce lactational heat load, and obtained data from shot samples of wild rabbits from northern Queensland to determine which of these might be most important in the field. Key results Rabbits spread food intake evenly across the 20-day lactation period and under hot conditions, captive wild individuals used body ...
Introduced European rabbits, Oryctolagus cuniculus, can severely damage Australian native vegetat... more Introduced European rabbits, Oryctolagus cuniculus, can severely damage Australian native vegetation but the problem is difficult to quantify because simple methods to estimate rabbit impacts are lacking. Management decision-making is often uncertain because of unknown relationships between rabbit density and damage. We tested simple quantitative sampling methods using belt transects to detect differences in critical characteristics of perennial vegetation communities affected by rabbit browsing: damage to individual juvenile shrubs and trees, and loss of recruitment cohorts. Rabbit density and relative abundance of larger herbivores were estimated from dung pellet density. The prevalence of identifiable rabbit browse on juvenile plants increased with increasing rabbit density and was higher for plant species considered by previous authors to be highly palatable than for moderately palatable or unpalatable species. At densities of ≥0.5 rabbits ha–1, highly palatable plant species we...
ABSTRACTThe effectiveness of invasive species control can be influenced by seasonal fluctuations ... more ABSTRACTThe effectiveness of invasive species control can be influenced by seasonal fluctuations in reproduction in response to environmental conditions. However, it is difficult to determine how demography and environmental conditions affect the efficacy of different control efforts from field trials alone. We incorporated an ontogenetic growth model into a hierarchical Bayesian mark‐recapture model to estimate age‐structured seasonal survival rates for European rabbits (Oryctolagus cuniculus) in Australia, based on a >15‐year data set. We integrated this demographic information into an individual‐based simulation model, which reproduces seasonal birth‐death processes, to test the effectiveness of pest‐management schemes that differed in intensity, specificity to age groups, and seasonal timing. Control measures that were simulated to affect only juveniles had a negligible effect on population size, whereas targeting subadults and adults led to considerable population declines w...
The release of myxoma virus (MYXV) and Rabbit Haemorrhagic Disease Virus (RHDV) in Australia with... more The release of myxoma virus (MYXV) and Rabbit Haemorrhagic Disease Virus (RHDV) in Australia with the aim of controlling overabundant rabbits has provided a unique opportunity to study the initial spread and establishment of emerging pathogens, as well as their co-evolution with their mammalian hosts. In contrast to MYXV, which attenuated shortly after its introduction, rapid attenuation of RHDV has not been observed. By studying the change in virulence of recent field isolates at a single field site we show, for the first time, that RHDV virulence has increased through time, likely because of selection to overcome developing genetic resistance in Australian wild rabbits. High virulence also appears to be favoured as rabbit carcasses, rather than diseased animals, are the likely source of mechanical insect transmission. These findings not only help elucidate the co-evolutionary interaction between rabbits and RHDV, but reveal some of the key factors shaping virulence evolution.
In Australia, the rabbit haemorrhagic disease virus (RHDV) has been used since 1996 to reduce num... more In Australia, the rabbit haemorrhagic disease virus (RHDV) has been used since 1996 to reduce numbers of introduced European rabbits (Oryctolagus cuniculus) which have a devastating impact on the native Australian environment. RHDV causes regular, short disease outbreaks, but little is known about how the virus persists and survives between epidemics. We examined the initial spread of RHDV to show that even upon its initial spread, the virus circulated continuously on a regional scale rather than persisting at a local population level and that Australian rabbit populations are highly interconnected by virus‐carrying flying vectors. Sequencing data obtained from a single rabbit population showed that the viruses that caused an epidemic each year seldom bore close genetic resemblance to those present in previous years. Together, these data suggest that RHDV survives in the Australian environment through its ability to spread amongst rabbit subpopulations. This is consistent with model...
European rabbits are exotic pests in Australia, New Zealand, parts of South America and Europe, a... more European rabbits are exotic pests in Australia, New Zealand, parts of South America and Europe, and on many islands. Their abundance, and the damage they cause, might be reduced by the release of naturally occurring or genetically modified organisms (GMOs) that act as biological control agents (BCAs). Some promising pathogens and parasites of European rabbits and other lagomorphs are discussed, with special reference to those absent from Australia as an example of the range of necessary considerations in any given case. The possibility of introducing these already-known BCAs into areas where rabbits are pests warrants further investigation. The most cost-effective method for finding potentially useful but as-yet undiscovered BCAs would be to maintain a global watch on new diseases and pathologies in domestic rabbits. The absence of wild European rabbits from climatically suitable parts of North and South America and southern Africa may indicate the presence there of useful BCAs, alt...
The European rabbit (Oryctolagus cuniculus) is a key prey species in Mediterranean ecosystems. Ho... more The European rabbit (Oryctolagus cuniculus) is a key prey species in Mediterranean ecosystems. However, it is also considered a pest on many oceanic islands, even though its true abundance and ecological effects on different island habitats are poorly understood. We present data on rabbit abundance for the best-preserved habitats of the Canary Islands, Spain (National Parks), including ecosystems differing in climate, topography, plant species richness and composition. Three methods of assessing rabbit abundance from faecal pellet density are compared to ascertain the best method to compare highly distinct habitats. The Cleaning method was used during spring, summer, autumn and winter to check whether there were differences in pellet degradation among habitats that could prevent comparisons between them. Rabbit abundance is determined by complex interactions among abiotic and biotic factor. Despite differences in climate conditions, the results obtained for rabbit density with fast methods correlated well with the slow Cleaning method. The Circular method was the most useful to work with for extensive sampling in different habitats. The best models for explaining rabbit density for all habitat types combined included tree cover, abiotic and topographic and climatic variables. Thus, factors influencing rabbit density vary depending on habitat type with Macaronesian laurel forests being the ecosystem least likely to be invaded by rabbits. The present study highlights that rabbits reach damaging densities for plant conservation in most areas on the Canary Islands.
With ongoing introductions into Australia since the 1700s, the European rabbit (Oryctolagus cunic... more With ongoing introductions into Australia since the 1700s, the European rabbit (Oryctolagus cuniculus) has become one of the most widely distributed and abundant vertebrate pests, adversely impacting Australia's biodiversity and agroeconomy. To understand the population and range dynamics of the species and its impacts better, occurrence and abundance data have been collected by researchers and citizens from sites covering a broad spectrum of climatic and environmental conditions in Australia. The lack of a common and accessible repository for these data has, however, limited their use in determining important spatiotemporal drivers of the structure and dynamics of the geographical range of rabbits in Australia. To meet this need, we created the Australian National Rabbit Database, which combines more than 50 yr of historical and contemporary survey data collected from throughout the range of the species in Australia. The survey data, obtained from a suite of complementary monit...
Wild rabbits in Australia developed genetic resistance to the myxoma virus, which was introduced ... more Wild rabbits in Australia developed genetic resistance to the myxoma virus, which was introduced as a biological control agent. However, little is known about the rate at which this evolutionary change occurred. We collated data from challenge trials that estimated rabbit resistance to myxomatosis in Australia and expressed resistance on a continuous scale, enabling trends in its development to be assessed over 45 years up to 1995. Resistance initially increased rapidly, followed by a plateau lasting ten years, before a second rapid increase occurred associated with the introduction of European rabbit fleas as myxoma virus vectors. By contrast, in the United Kingdom, where rabbit flea vectors were already present when the myxoma virus initially spread, resistance developed more slowly. No estimates of rabbit resistance to myxomatosis have been made for almost 30 years, despite other highly lethal rabbit pathogens becoming established worldwide. Continued testing of wild-caught rabbi...
European rabbit fleas were released among Australian wild rabbits in the late 1960s to supplement... more European rabbit fleas were released among Australian wild rabbits in the late 1960s to supplement mosquitoes as vectors of myxoma virus. Data from study sites across southern Australia in the 1960s and 1970s are reviewed to discern common elements of flea-borne myxomatosis epizootics and a simple model is proposed to explain how virus virulence and food quality interact to determine rabbit abundance. Low, stable populations of rabbits implied that, despite virus attenuation and increased rabbit disease resistance, flea-borne myxomatosis was extremely important in controlling rabbit populations. Despite the enhancement of myxomatosis, livestock producers benefitted little from the additional pasture because marketing difficulties were not conducive to industry growth. Native wildlife likely benefitted, nonetheless.
In 1984, an unknown disease was reported in the People' s Republic of China among Angora rabbits ... more In 1984, an unknown disease was reported in the People' s Republic of China among Angora rabbits which had been recently imported from the German Democratic Republic (28). Within a few months, the disease had spread widely through commercial rabbitries in the People' s Republic of China (59) and had also reached the Republic of Korea (41). Investigators in the People' s Republic of China rapidly developed an inactivated vaccine, using livers of infected rabbits, to control the disease (25). Nevertheless, a new unknown disease, initially named 'Malattia-X', appeared in domestic rabbits in Italy in 1986 (9), leading to the deaths of millions of domestic rabbits. This new disease soon appeared in other countries in Europe (34), and in 1987-1988, a link was established with the viral haemorrhagic disease of rabbits in the People' s Republic of China. Research on this new disease was rapidly initiated in
The rabbit flea Caenopsylla laptevi ibera occurs in arid environments of central and eastern Spai... more The rabbit flea Caenopsylla laptevi ibera occurs in arid environments of central and eastern Spain. Although the fleas breed during the coolest, most humid part of the year, the larvae survive and grow in sand at only 50-60 % relative humidity. At 22°C and 80 % relative humidity eggs hatch in six days and the cocoon stage is reached 10-1 1 days after hatching. Female fleas emerge from pupation at about 1 7 days after cocoon spinning; males emerge a little later at a mean of 20 days. Adult fleas are mainly found on the host Oryctolagus cuniculus. Measurements of burrow microclimate confirmed that in southeastern Spain burrow humidity was adequate for the development of C. /. ibera larvae over most of the year. However, breeding may be restricted for at least part of the year, as the larvae of C. I. ibera apparently cannot complete development at 25 °C or above. In the laboratory, fleas can enter a prolonged quiescent period while in the cocoon. This is possibly a facultative, pre-pupal diapause and the likely mechanism that accounts for the disappearance of adult fleas from the field by spring and their reappearance each autumn.
This paper challenges conclusions of Caughley et al. (1980) that the abundance of red kangaroos (... more This paper challenges conclusions of Caughley et al. (1980) that the abundance of red kangaroos (Macropus rufus) in western New South Wales is solely due to lack of dingoes (Canis lupus dingo), and vice versa for neighbouring South Australia. A Dingo Barrier Fence divides the two different ecological systems, which have sheep in New South Wales and cattle in South Australia. This paper re-examines in particular whether there is an environmental gradient across the Fence that was dismissed by Caughley et al. This paper concludes to the contrary, that there is a strong environmental gradient. Our aerial surveys demonstrate significantly that habitats favouring red kangaroos are prevalent in New South Wales today, but are very scarce or absent in South Australian landscapes. Aerial surveys were used in both studies, but designs differed. Caughley et al. flew at right angles across the Fence on paths 28 km apart. Flights would have crossed the south-westerly streamlines rarely. Our flig...
ELISA techniques developed for the veterinary diagnosis of Rabbit Haemorrhagic Disease (RHD) in d... more ELISA techniques developed for the veterinary diagnosis of Rabbit Haemorrhagic Disease (RHD) in domestic rabbits were used for studying the epidemiology of RHD in Australian wild rabbits. The combination of ELISA techniques that distinguished IgA, IgG and IgM antibody responses and a longitudinal data set, mainly based on capture-mark-recapture of rabbits, provided a reliable basis for interpreting serology and set the criteria used to classify rabbits' immunological status. Importantly, young with maternal antibodies, immune rabbits and rabbits apparently re-exposed to RHD were readily separated. Three outbreaks of RHD occurred in 1996–7. The timing of RHD outbreaks was mainly driven by recruitment of young rabbits that generally contracted RHD after they lost their maternally derived immunity. Young that lost maternal antibodies in summer were not immediately infected, apparently because transmission of RHDV slows at that time, but contracted RHD in the autumn when conditions ...
This review considers the history of the discovery of the rabbit haemorrhagic disease virus (RHDV... more This review considers the history of the discovery of the rabbit haemorrhagic disease virus (RHDV) and its spread throughout the world in domestic and wild rabbits, which led eventually to its deliberate release into Australia and New Zealand for the control of a major pest, the introduced wild rabbit. The physical and genetic structure of RHDV is now well understood, and its pathogenic effects are also well known. The epidemiology of rabbit haemorrhagic disease (RHD) has been clearly documented in the field in European countries, Australia and New Zealand. Since its initial spread through largely naïve populations of wild rabbits it has established a pattern of mainly annual epizootics in most areas. The timing of epizootics is dependent on climatic variables that determine when rabbits reproduce and the appearance of new, susceptible rabbits in the population. The activity of RHDV is also influenced by climatic extremes that presumably affect its persistence and the behaviour of i...
Context European rabbits evolved in Spain and Portugal and are adapted to winter-rainfall Mediter... more Context European rabbits evolved in Spain and Portugal and are adapted to winter-rainfall Mediterranean habitats. On introduction into Australia in 1859, wild rabbits quickly colonised similar habitats across the southern two-thirds of the continent. However, over the past 40 years, they have spread further into monsoonal savanna habitats in northern Queensland. Aims To explain this, we considered adaptive responses of wild rabbits to hot conditions, particularly potential mechanisms for reducing the heat load of lactation, which has been identified as a likely limiting factor. Methods We analysed data from captive wild rabbits to identify mechanisms that could potentially reduce lactational heat load, and obtained data from shot samples of wild rabbits from northern Queensland to determine which of these might be most important in the field. Key results Rabbits spread food intake evenly across the 20-day lactation period and under hot conditions, captive wild individuals used body ...
Introduced European rabbits, Oryctolagus cuniculus, can severely damage Australian native vegetat... more Introduced European rabbits, Oryctolagus cuniculus, can severely damage Australian native vegetation but the problem is difficult to quantify because simple methods to estimate rabbit impacts are lacking. Management decision-making is often uncertain because of unknown relationships between rabbit density and damage. We tested simple quantitative sampling methods using belt transects to detect differences in critical characteristics of perennial vegetation communities affected by rabbit browsing: damage to individual juvenile shrubs and trees, and loss of recruitment cohorts. Rabbit density and relative abundance of larger herbivores were estimated from dung pellet density. The prevalence of identifiable rabbit browse on juvenile plants increased with increasing rabbit density and was higher for plant species considered by previous authors to be highly palatable than for moderately palatable or unpalatable species. At densities of ≥0.5 rabbits ha–1, highly palatable plant species we...
ABSTRACTThe effectiveness of invasive species control can be influenced by seasonal fluctuations ... more ABSTRACTThe effectiveness of invasive species control can be influenced by seasonal fluctuations in reproduction in response to environmental conditions. However, it is difficult to determine how demography and environmental conditions affect the efficacy of different control efforts from field trials alone. We incorporated an ontogenetic growth model into a hierarchical Bayesian mark‐recapture model to estimate age‐structured seasonal survival rates for European rabbits (Oryctolagus cuniculus) in Australia, based on a >15‐year data set. We integrated this demographic information into an individual‐based simulation model, which reproduces seasonal birth‐death processes, to test the effectiveness of pest‐management schemes that differed in intensity, specificity to age groups, and seasonal timing. Control measures that were simulated to affect only juveniles had a negligible effect on population size, whereas targeting subadults and adults led to considerable population declines w...
The release of myxoma virus (MYXV) and Rabbit Haemorrhagic Disease Virus (RHDV) in Australia with... more The release of myxoma virus (MYXV) and Rabbit Haemorrhagic Disease Virus (RHDV) in Australia with the aim of controlling overabundant rabbits has provided a unique opportunity to study the initial spread and establishment of emerging pathogens, as well as their co-evolution with their mammalian hosts. In contrast to MYXV, which attenuated shortly after its introduction, rapid attenuation of RHDV has not been observed. By studying the change in virulence of recent field isolates at a single field site we show, for the first time, that RHDV virulence has increased through time, likely because of selection to overcome developing genetic resistance in Australian wild rabbits. High virulence also appears to be favoured as rabbit carcasses, rather than diseased animals, are the likely source of mechanical insect transmission. These findings not only help elucidate the co-evolutionary interaction between rabbits and RHDV, but reveal some of the key factors shaping virulence evolution.
In Australia, the rabbit haemorrhagic disease virus (RHDV) has been used since 1996 to reduce num... more In Australia, the rabbit haemorrhagic disease virus (RHDV) has been used since 1996 to reduce numbers of introduced European rabbits (Oryctolagus cuniculus) which have a devastating impact on the native Australian environment. RHDV causes regular, short disease outbreaks, but little is known about how the virus persists and survives between epidemics. We examined the initial spread of RHDV to show that even upon its initial spread, the virus circulated continuously on a regional scale rather than persisting at a local population level and that Australian rabbit populations are highly interconnected by virus‐carrying flying vectors. Sequencing data obtained from a single rabbit population showed that the viruses that caused an epidemic each year seldom bore close genetic resemblance to those present in previous years. Together, these data suggest that RHDV survives in the Australian environment through its ability to spread amongst rabbit subpopulations. This is consistent with model...
European rabbits are exotic pests in Australia, New Zealand, parts of South America and Europe, a... more European rabbits are exotic pests in Australia, New Zealand, parts of South America and Europe, and on many islands. Their abundance, and the damage they cause, might be reduced by the release of naturally occurring or genetically modified organisms (GMOs) that act as biological control agents (BCAs). Some promising pathogens and parasites of European rabbits and other lagomorphs are discussed, with special reference to those absent from Australia as an example of the range of necessary considerations in any given case. The possibility of introducing these already-known BCAs into areas where rabbits are pests warrants further investigation. The most cost-effective method for finding potentially useful but as-yet undiscovered BCAs would be to maintain a global watch on new diseases and pathologies in domestic rabbits. The absence of wild European rabbits from climatically suitable parts of North and South America and southern Africa may indicate the presence there of useful BCAs, alt...
The European rabbit (Oryctolagus cuniculus) is a key prey species in Mediterranean ecosystems. Ho... more The European rabbit (Oryctolagus cuniculus) is a key prey species in Mediterranean ecosystems. However, it is also considered a pest on many oceanic islands, even though its true abundance and ecological effects on different island habitats are poorly understood. We present data on rabbit abundance for the best-preserved habitats of the Canary Islands, Spain (National Parks), including ecosystems differing in climate, topography, plant species richness and composition. Three methods of assessing rabbit abundance from faecal pellet density are compared to ascertain the best method to compare highly distinct habitats. The Cleaning method was used during spring, summer, autumn and winter to check whether there were differences in pellet degradation among habitats that could prevent comparisons between them. Rabbit abundance is determined by complex interactions among abiotic and biotic factor. Despite differences in climate conditions, the results obtained for rabbit density with fast methods correlated well with the slow Cleaning method. The Circular method was the most useful to work with for extensive sampling in different habitats. The best models for explaining rabbit density for all habitat types combined included tree cover, abiotic and topographic and climatic variables. Thus, factors influencing rabbit density vary depending on habitat type with Macaronesian laurel forests being the ecosystem least likely to be invaded by rabbits. The present study highlights that rabbits reach damaging densities for plant conservation in most areas on the Canary Islands.
With ongoing introductions into Australia since the 1700s, the European rabbit (Oryctolagus cunic... more With ongoing introductions into Australia since the 1700s, the European rabbit (Oryctolagus cuniculus) has become one of the most widely distributed and abundant vertebrate pests, adversely impacting Australia's biodiversity and agroeconomy. To understand the population and range dynamics of the species and its impacts better, occurrence and abundance data have been collected by researchers and citizens from sites covering a broad spectrum of climatic and environmental conditions in Australia. The lack of a common and accessible repository for these data has, however, limited their use in determining important spatiotemporal drivers of the structure and dynamics of the geographical range of rabbits in Australia. To meet this need, we created the Australian National Rabbit Database, which combines more than 50 yr of historical and contemporary survey data collected from throughout the range of the species in Australia. The survey data, obtained from a suite of complementary monit...
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Papers by Brian Cooke