Marsh rabbit mortalities tie pythons to the precipitous decline of mammals in the Everglades

To address the ongoing debate over the impact of invasive species on native terrestrial wildlife, we conducted a large-scale experiment to test the hypothesis that invasive Burmese pythons (Python molurus bivittatus) were a cause of the precipitous decline of mammals in Everglades National Park (ENP). Evidence linking pythons to mammal declines has been indirect and there are reasons to question whether pythons, or any predator, could have caused the precipitous declines seen across a range of mammalian functional groups. Experimentally manipulating marsh rabbits, we found that pythons accounted for 77% of rabbit mortalities within 11 months of their translocation to ENP and that python predation appeared to preclude the persistence of rabbit populations in ENP. On control sites, outside of the park, no rabbits were killed by pythons and 71% of attributable marsh rabbit mortalities were classified as mammal predations. Burmese pythons pose a serious threat to the faunal communities and ecological functioning of the Greater Everglades Ecosystem, which will probably spread as python populations expand their range.     

Can widespread generalist predators affect keystone prey? A case study with red foxes and European rabbits in their native range

Widespread generalist predators may affect declining keystone prey populations. However, this phenomenon is not well understood. In this paper, we assessed whether the abundance and population growth of European rabbits Oryctolagus cuniculus, a keystone prey species in Mediterranean Iberia, was related to the abundance and diet of red foxes, Vulpes vulpes, a widespread generalist predator. In a locality in central Spain, where rabbit population abundance declined, we estimated rabbit abundance during almost 3 years and determined fox abundance and diet during two concurrent years. We calculated a fox predation index (percentage of consumed rabbit biomass × fox abundance) to assess the importance of rabbits to foxes. We employed a multi–model approach to explain rabbit abundance and population growth. Foxes consumed between 60 and 99 % rabbit biomass in their diets, and this was independent of rabbit abundance. Periods of higher fox predation index coincided with lower rabbit density and vice versa. Two models best explained rabbit abundance and four rabbit population growth. They included the fox predation index and its interaction with rabbit abundance during the previous month. Altogether, fox predation, intraspecific density dependence, and their interaction partly explained rabbit population dynamics. We conclude that in order to propel the recovery of the rabbit in Iberia, it is essential to better understand the role of these factors in driving the abundance of the species.     

Testing the threat-sensitive predator avoidance hypothesis: physiological responses and predator pressure in wild rabbits

Predation is a strong selective force with both direct and indirect effects on an animal’s fitness. In order to increase the chances of survival, animals have developed different antipredator strategies. However, these strategies have associated costs, so animals should assess their actual risk of predation and shape their antipredator effort accordingly. Under a stressful situation, such as the presence of predators, animals display a physiological stress response that might be proportional to the risk perceived. We tested this hypothesis in wild European rabbits (Oryctolagus cuniculus), subjected to different predator pressures, in Doñana National Park (Spain). We measured the concentrations of fecal corticosterone metabolites (FCM) in 20 rabbit populations. By means of track censuses we obtained indexes of mammalian predator presence for each rabbit population. Other factors that could modify the physiological stress response, such as breeding status, food availability and rabbit density, were also considered. Model selection based on information theory showed that predator pressure was the main factor triggering the glucocorticoid release and that the physiological stress response was positively correlated with the indexes of the presence of mammalian carnivore predators. Other factors, such as food availability and density of rabbits, were considerably less important. We conclude that rabbits are able to assess their actual risk of predation and show a threat-sensitive physiological response.     

Predictors of clutch predation of a globally significant avifauna in New Zealand's braided river ecosystems

Predation by introduced mammals is decimating New Zealand's indigenous fauna. Understanding factors that influence this process allows resources for predator control to be applied with maximum effect. This study examines how predation of a secondary prey species (a relatively common but declining native plover, the banded dotterel Charadrius bicinctus ) varied with reductions in abundance of a major prey source (rabbits), kill-trapping of predators, nest density and habitat complexity. Banded dotterels mostly nest in open braided riverbeds alongside a number of endemic threatened species. We measured the fate of 753 dotterel clutches exposed to predation by cats, ferrets and hedgehogs. We found key times and places of high predation risk. Immediately after widespread reduction in rabbit populations by rabbit haemorrhagic disease (RHD), clutch predation rates were almost as high (mean, 50%) as those recorded during past rabbit poisoning programmes (mean, 57%). Both rates were significantly higher than the mean predation rate of 22% without rabbit control, suggesting a shift in predator diet immediately after rabbit population declines. Unlike after rabbit poisoning, clutch predation rate remained high in the years after RHD. Other patterns observed included higher clutch predation rate where nest density was lower, suggesting that predation can potentially cause local extinction. Clutch predation was also higher along riverbed margins where vegetation was dense. There was equivocal evidence for an effect of predator kill-trapping on clutch predation rate. Management strategies that could potentially reduce clutch predation risks include focusing predator mitigation measures during periods of rabbit decline, maintaining them for more than one breeding season if the rabbit declines are widespread (e.g. RHD epidemics), and applying greater effort at sites with relatively low nest density and along riverbed margins where predator use is more frequent.     

Survival of Juvenile Pygmy Rabbits

ABSTRACT Until recently, natal behavior of pygmy rabbits (Brachylagus idahoensis) was largely unknown, and no information on survival of free-ranging juveniles was available. We evaluated survival of radiotagged juvenile pygmy rabbits at 2 sites in east-central Idaho, USA, during 2004 and 2005. We captured juveniles (n 58) shortly after they emerged from natal burrows. Mortality rates were high and variable, ranging from 27% for females during 2004 to 63% for males during 2005. Approximately 69% of mortalities were attributed to predation. We evaluated variables influencing juvenile survival through 18 weeks old using known-fate models in Program MARK. We expected survival to decline around the age of natal dispersal and to be lower for young born later in the season. We evaluated 14 candidate models that included sex, year, study area, and relative date of birth within each year. Model selection results did not indicate strong support for any single combination of variables, and 8 competing models all included effects of relative date of birth, year, and study area. These results revealed substantial variability in survival of juveniles across multiple factors, and we documented similar patterns for adult pygmy rabbits. Such high variability in survival over relatively small spatial and temporal scales might contribute to marked fluctuations in populations of pygmy rabbits and, hence, managers interested in monitoring this species might consider monitoring multiple populations across broader geographic areas to assess regional trends in numbers.     

Pests controlling pests: does predator control lead to greater European rabbit abundance in Australasia?

相似文献   

Breeding like rabbits: global patterns of variability and determinants of European wild rabbit reproduction

The importance of European wild rabbits Oryctolagus cuniculus both as a pest in some areas and as a key prey species in others emphasizes the need to understand what controls its population dynamics worldwide. In this study we aim to describe the variability in rabbit breeding parameters and identify the main factors that govern it at a global scale. Despite the species' wide distribution, some reproductive traits such as short sexual maturity age, duration of gestation period, and existence of post-partum oestrus are similar in all populations conferring the species a high breeding potential. Nevertheless, other aspects vary substantially among regions resulting in highly different population productivities and also across years. These latter parameters are the length of breeding season, proportion of pregnant females, age of first reproduction, and number and size of litters. Our results show that variability in these attributes is mainly affected by a combination of environmental controls (i.e. temperature, resource availability, and photoperiod) and individual properties (age and body weight). On the other hand, the effect of other factors such as population density could not be demonstrated. Knowledge about the factors driving global reproduction patterns of European wild rabbits will improve our understanding about their population dynamics, and thus will help to optimize the management and conservation of their populations.     

Climate change causing phase transitions of walleye pollock (Theragra chalcogramma) recruitment dynamics

In 1976 the North Pacific climate shifted, resulting in an average increase of the water temperature. In the Gulf of Alaska the climate shift was followed (i.e. early 1980s) by a gradual but dramatic increase in the abundance of groundfish species that typically prey on pre-recruitment stages of walleye pollock. In the present study we used a previously parameterized model to investigate the effect of these climate and biological changes on the recruitment dynamics of walleye pollock in the Gulf of Alaska. Simulations covered the 1970-2000 time frame and emphasized the medium-to-long temporal scale (i.e. about 5-10 years) of environmental variability. Results showed that during periods characterized by high sea surface temperature and high predation on juvenile pollock stages, recruitment variability and magnitude were below average, and recruitment control was delayed to stages older than the 0-group. Opposite dynamics (i.e. high abundance and variability, and early recruitment control) occurred during periods characterized by low temperature and predation. These results are in general agreement with empirical observations, and allowed us to formulate causal explanations for their occurrence. We interpreted the delay of recruitment control and the reduction of variability as an effect of increased constraint on the abundance of post age-0 stages, in turn imposed by high density dependence and predation mortality. On the other hand, low density-dependence and predation favoured post age-0 survival, and allowed for an unconstrained link between larval and recruitment abundance. Our findings demonstrate that the dominant mechanisms of pollock survival change over contrasting climate regimes. Such changes may in turn cause a phase transition of recruitment dynamics with profound implications for the management of the entire stock.     

Contrasting age-specific recruitment and survival at different spatial scales: a case study with the European storm petrel

Evolutionary studies on optimal decisions or conservation guidelines are often derived by generalising patterns from a single population, while inter‐population variability in life‐history traits is seldom considered. We investigated here how survival and recruitment probabilities changed with age at different geographical scales using the encounter histories of 5523 European storm petrels from three Mediterranean colonies, and also how our estimates of these parameters might be expected to affect population growth rates using population matrix models. We recorded similar patterns among colonies, but also important biological differences. Local survival, recruitment and breeding success increased with age at all colonies; the most distant of three colonies (Marettimo Is.) showed the largest differences. Strikingly, differences in recruitment were also found between two adjacent colonies (two caves from Benidorm Is.). Birds marked as adults from Marettimo and Benidorm colonies had a different survival, whereas we found no differences within Benidorm. Differences in survival were no longer apparent between the two islands at the end of the study following a reduction in predation by specialist gulls at Benidorm. Since birds marked as fledglings mostly recruited near the end of the study, their overall survival was high and in turn similar among colonies. Results from our population matrix models suggested that different age‐dependent patterns of demographic parameters can lead to similar population growth rates. Variability appeared to be greater for recruitment and the most sensitive parameter was adult survival. Thus conservation actions targeting this vulnerable species should focus on factors influencing adult survival. Differences in survival and recruitment among colonies could reflect the spatial heterogeneity in mortality due to predation and colony‐specific density dependent processes. Results highlight the importance of taking into account the potential spatio‐temporal heterogeneity among populations in vital rates, even in those traits that life‐history theory considers less important in driving population dynamics.     

Regulation of root vole population dynamics by food supply and predation: a two-factor experiment

This paper reports the effects of food supply, predation and the interaction between them on the population dynamics of root voles, Microtus oeconomus , by adopting factorial experiments in field enclosures. This two-factor experiment proved the general hypothesis that food supply and predation had independent and additive effects on population dynamics of root voles. The experimental results proved the following predictions: (1) predation reduced population density and recruitment significantly; (2) food supply increased population density; (3) predation and food supply influenced spacing behavior of root voles separately and additively: Exposure to predation reduced long movements of root voles between trapping sessions; additional food supply reduced aggression level and home range size of root voles. Less movement of individuals that exposed to predators possibly reduced their opportunity of obtaining food and lessened population survival rate, which led population density to decrease. Smaller home range and lower aggression level could make higher population density tolerable. The interactive effect of predation and food on home range size was highly significant (P=0.0082<0.01). The interactive effect of food and predation on dispersal rate was significant (P<0.01). From the experimental results, we conclude that the external factors (predation, food supply) were more effective than internal factors (spacing behavior) in determining population density of root voles – under the most favorable external conditions (−P, +F treatment), the mean density and mean recruitment of root vole population was the highest; under the most unfavorable external conditions (+P, −F treatment), the mean density and mean recruitment of root vole population was the lowest.     

Mortality patterns over 3 years in a sparse population of wild rabbits (Oryctolagus cuniculus) in New Zealand, with an emphasis on rabbit haemorrhagic disease (RHD)

A sparse rabbit population in New Zealand was monitored over 3 years to assess the temporal dynamics of rabbit mortality, in particular to understand the mortality patterns due to rabbit haemorrhagic disease (RHD). A total of 107 deaths were recorded, of which 93 could be classified by cause. The predominant cause of mortality was predation (47% of deaths), followed by RHD (20%). Deaths due to RHD were clustered in time (within 3 weeks), predation occurred most actively from late autumn to spring, while other causes of death did not show pronounced seasonal peaks. No differences in cause-specific death risk were observed between sexes. Predation was the main cause of death in younger animals, while RHD mortality occurred mainly in older rabbits. This study has shown that the impact of RHD can vary considerably between years, indicating that a variety of risk factors are required to initiate a RHD epidemic with a high mortality rate among rabbits.     

A combination of hydrodynamical and statistical modelling reveals non-stationary climate effects on fish larvae distributions

Biological processes and physical oceanography are often integrated in numerical modelling of marine fish larvae, but rarely in statistical analyses of spatio-temporal observation data. Here, we examine the relative contribution of inter-annual variability in spawner distribution, advection by ocean currents, hydrography and climate in modifying observed distribution patterns of cod larvae in the Lofoten-Barents Sea. By integrating predictions from a particle-tracking model into a spatially explicit statistical analysis, the effects of advection and the timing and locations of spawning are accounted for. The analysis also includes other environmental factors: temperature, salinity, a convergence index and a climate threshold determined by the North Atlantic Oscillation (NAO). We found that the spatial pattern of larvae changed over the two climate periods, being more upstream in low NAO years. We also demonstrate that spawning distribution and ocean circulation are the main factors shaping this distribution, while temperature effects are different between climate periods, probably due to a different spatial overlap of the fish larvae and their prey, and the consequent effect on the spatial pattern of larval survival. Our new methodological approach combines numerical and statistical modelling to draw robust inferences from observed distributions and will be of general interest for studies of many marine fish species.     

Ecosystem Scale Declines in Elk Recruitment and Population Growth with Wolf Colonization: A Before-After-Control-Impact Approach

The reintroduction of wolves (Canis lupus) to Yellowstone provided the unusual opportunity for a quasi-experimental test of the effects of wolf predation on their primary prey (elk – Cervus elaphus) in a system where top-down, bottom-up, and abiotic forces on prey population dynamics were closely and consistently monitored before and after reintroduction. Here, we examined data from 33 years for 12 elk population segments spread across southwestern Montana and northwestern Wyoming in a large scale before-after-control-impact analysis of the effects of wolves on elk recruitment and population dynamics. Recruitment, as measured by the midwinter juvenile∶female ratio, was a strong determinant of elk dynamics, and declined by 35% in elk herds colonized by wolves as annual population growth shifted from increasing to decreasing. Negative effects of population density and winter severity on recruitment, long recognized as important for elk dynamics, were detected in uncolonized elk herds and in wolf-colonized elk herds prior to wolf colonization, but not after wolf colonization. Growing season precipitation and harvest had no detectable effect on recruitment in either wolf treatment or colonization period, although harvest rates of juveniles∶females declined by 37% in wolf-colonized herds. Even if it is assumed that mortality due to predation is completely additive, liberal estimates of wolf predation rates on juvenile elk could explain no more than 52% of the total decline in juvenile∶female ratios in wolf-colonized herds, after accounting for the effects of other limiting factors. Collectively, these long-term, large-scale patterns align well with prior studies that have reported substantial decrease in elk numbers immediately after wolf recolonization, relatively weak additive effects of direct wolf predation on elk survival, and decreased reproduction and recruitment with exposure to predation risk from wolves.     

Effects of regional climate and small‐scale habitat quality on performance in the relict species Ramonda myconi

Abstract. The Mediterranean Basin harbours paleo‐endemic species with a highly restricted and fragmented distribution. Many of them might also be of the remnant type, for which the regional dynamics depends on the persistence of extant populations. Therefore, a key issue for the long‐term persistence of these species is to assess the variability and effects of ecological factors determining plant performance. We investigated the spatio‐temporal variability in plant traits and ecological factors of Ramonda myconi, a preglacial relict species with remnant dynamics, in 5 populations over 4–7 yr. Ecological factors contributing to fecundity showed a high degree of between‐year variability. Pre‐dispersal fruit predation had a minor influence on total reproductive output, and most of the variability was found among individuals within populations and years. Spatio‐temporal variability in growth and survival was rather low but significant, whereas recruitment showed important between‐population variability. Among‐year variability in fecundity and growth was related to climatic fluctuations on a regional scale, notably rainfall and temperature in a particular period, while the spatial variability in survival and recruitment was explained by within‐population (patch) habitat quality. Although R. myconi is able to withstand repeated periods of drought, water availability seems to be the most important factor affecting plant performance in all the study populations. These findings suggest that the long‐term persistence of species showing remnant population dynamics in habitats under the influence of Mediterranean climate might be threatened by increased aridity as a result of climate change.     

The demographic impact of extreme events: stochastic weather drives survival and population dynamics in a long-lived seabird

1. Most scenarios for future climate change predict increased variability and thus increased frequency of extreme weather events. To predict impacts of climate change on wild populations, we need to understand whether this translates into increased variability in demographic parameters, which would lead to reduced population growth rates even without a change in mean parameter values. This requires robust estimates of temporal process variance, for example in survival, and identification of weather covariates linked to interannual variability. 2. The European shag Phalacrocorax aristotelis (L.) shows unusually large variability in population size, and large-scale mortality events have been linked to winter gales. We estimated first-year, second-year and adult survival based on 43 years of ringing and dead recovery data from the Isle of May, Scotland, using recent methods to quantify temporal process variance and identify aspects of winter weather linked to survival. 3. Survival was highly variable for all age groups, and for second-year and adult birds process variance declined strongly when the most extreme year was excluded. Survival in these age groups was low in winters with strong onshore winds and high rainfall. Variation in first-year survival was not related to winter weather, and process variance, although high, was less affected by extreme years. A stochastic population model showed that increasing process variance in survival would lead to reduced population growth rate and increasing probability of extinction. 4. As in other cormorants, shag plumage is only partially waterproof, presumably an adaptation to highly efficient underwater foraging. We speculate that this adaptation may make individuals vulnerable to rough winter weather, leading to boom-and-bust dynamics, where rapid population growth under favourable conditions allows recovery from periodic large-scale weather-related mortality. 5. Given that extreme weather events are predicted to become more frequent, species such as shags that are vulnerable to such events are likely to exhibit stronger reductions in population growth than would be expected from changes in mean climate. Vulnerability to extreme events thus needs to be accounted for when predicting the ecological impacts of climate change.     

Density‐independent predation affects migrants and residents equally in a declining partially migratory elk population

Migration is expected to benefit individuals through exposure to higher quality forage and reducing predation rates more than non‐migratory conspecifics. Previous studies of partially migratory ungulates (with migrant and resident individuals) have focused on bottom–up factors regulating resident and migrant segments, yet differential predation between strategies could also be a density‐dependent regulatory mechanism. Our study tested for density‐dependence in mortality, as well as mechanisms of ­bottom–up or top–down regulation in the resident and migrant portions of the partially migratory Ya Ha Tinda elk population. We tested for density dependence in adult female and juvenile survival rates, and then discriminated between predator‐ and food‐regulation hypotheses by testing for density‐dependence amongst mortality causes for adult female elk. Notably, the population declined almost 70% from near previously published estimates of carrying capacity over 10 years, providing ideal conditions to test for density dependence. In contrast to predictions, we found only weak support for density dependence in adult survival and juvenile survival. We also found few differences between migrant and resident elk in adult or juvenile survival, though juvenile survival differences were biologically significant. Predation by humans and grizzly bears was density dependent, but similar between migratory strategies. Predation by wolves was the leading known cause of mortality, yet remained constant with declining elk density equally for both migrant and resident elk, indicating wolf predation was density‐independent. Instead of being strongly regulated by food or predation, we found adult female survival was driven by density‐independent predation and climatic factors. The few differences between migratory strategies suggest equivalent fitness payoffs for migrants and residents. This population is being limited by density‐independent predation leading to declines of both migratory strategies. Our results challenge classical predator–prey theory, and call for better integration between predator–prey and migration theory.     

Foxes, rabbits, alternative prey and rabbit calicivirus disease: consequences of a new biological control agent for an outbreaking species in Australia

1. Rabbit calicivirus disease (RCD; also known as rabbit haemorrhagic disease) has been introduced recently as a biocontrol agent for rabbits in Australia. The consequences for fox populations that use rabbits as primary prey, for populations of alternative native prey, and for pastures, were examined using a model for rabbit- and fox-prone areas of semi-arid southern Australia.
2. Existing data were used to quantify the interactions of foxes, rabbits and pasture. A generic model for predation on native herbivores was constructed by modifying the density-dependent (Type III) functional response of foxes to rabbits to a depensatory (Type II) response that is appropriate for alternative prey. Similar dependence on pasture biomass was assumed for the dynamics of both rabbits and alternative prey in order to identify clearly the consequences of differing predation. In the absence of quantitative data for Australian conditions, the epidemiology of RCD was simulated empirically to mimic a range of potential patterns of occurrence.
3. For semi-arid Australia the model predicts that as the frequency and intensity of RCD epizootics increases: (i) the mean abundance of rabbits will decline, as will the frequency of eruptions of rabbits; (ii) there may be little increase in mean pasture biomass and a small decrease in periods of very low pasture biomass when competition between herbivores is most intense; (iii) the mean abundance of foxes will decline; (iv) there will be a reduced frequency of occasions when rabbit density is low but fox density is high due to a lag in the response of predator populations; and (v) there is potential for an increase in the mean abundance of alternative prey and in the proportion of time their density exceeds a threshold comparable to that currently required for eruptions of rabbits.     

食物、捕食和种间竞争对东方田鼠种群动态的作用

采用2×2×2析因实验设计,在野外围栏条件下,测定食物、捕食和竞争物种黑线姬鼠(Apodemus agrarius)对东方田鼠(Microtus fortis)种群动态作用的格局.食物可利用性、捕食及种间竞争的独立作用对种群最小存活数均具有极显著的效应,除捕食与种间竞争的交互作用接近显著水平外,食物与种间竞争、食物与捕食者以及三者间的交互作用均不显著;三类外部因子对种群补充量的独立作用效应均达到极显著水平,且对种群补充量的作用具有累加效应;食物可利用性、捕食及种间竞争对种群繁殖成体的比例具有极显著的作用;三类外部因子对种群幼体与成体的比例具有极显著的作用.对种群年龄结构而言,与捕食者及种间竞争比较,食物可利用性是相对较弱的影响因子,在任何捕食与种间竞争交互作用条件下,食物的作用均不显著;三类外部因子均能显著地影响东方田鼠的体重增长率,但三者的交互作用对其影响不显著;MANOVA结果表明,捕食对成体存活率的作用最强烈,其次,为食物可利用性,种间竞争的作用最弱,但三者的交互作用效应不显著.对幼体的存活时间,除捕食的作用接近显著水平外,食物可利用性及种间竞争的作用均不显著.结果提供了食物可利用性、捕食和种间竞争对东方田鼠种群动态作用的充分证据,验证了食物、捕食和种间竞争对田鼠类种群动态具有独立或累加效应的总假设.     

Responses of a top and a meso predator and their prey to moon phases

We compared movement patterns and rhythms of activity of a top predator, the Iberian lynx Lynx pardinus, a mesopredator, the red fox Vulpes vulpes, and their shared principal prey, the rabbit Oryctolagus cuniculus, in relation to moon phases. Because the three species are mostly nocturnal and crepuscular, we hypothesized that the shared prey would reduce its activity at most risky moon phases (i.e. during the brightest nights), but that fox, an intraguild prey of lynx, would avoid lynx activity peaks at the same time. Rabbits generally moved further from their core areas on darkest nights (i.e. new moon), using direct movements which minimize predation risk. Though rabbits responded to the increased predation risk by reducing their activity during the full moon, this response may require several days, and the moon effect we observed on the rabbits had, therefore, a temporal gap. Lynx activity patterns may be at least partially mirroring rabbit activity: around new moons, when rabbits moved furthest and were more active, lynxes reduced their travelling distances and their movements were concentrated in the core areas of their home ranges, which generally correspond to areas of high density of rabbits. Red foxes were more active during the darkest nights, when both the conditions for rabbit hunting were the best and lynxes moved less. On the one hand, foxes increased their activity when rabbits were further from their core areas and moved with more discrete displacements; on the other hand, fox activity in relation to the moon seemed to reduce dangerous encounters with its intraguild predator.     

Key factors determining the seasonal population growth rate of European wild rabbits and their implications for management

Recently, the European rabbit (Oryctolagus cuniculus) has received contrasting considerations due to its multidimensional role in the Mediterranean ecosystems. Within this framework, knowledge of factors determining its population size may have important consequences for designing an effective management plan. In this paper, we quantified the combined influence of the major demographic and mechanistic factors on seasonal population fluctuation of European rabbits on Lemnos Island (Greece), during 2007–2009. We developed a hypothetical model taking into account direct (productivity, predation, hunting pressure, food shortage, habitat treatment) and indirect factors (soil moisture, adverse weather conditions) using structural equation modeling. We tested for their influence on the seasonal population growth rate (spgr) as determined by line transects to estimate rabbit abundance. The productivity induced higher pgr. Food shortage, which is affected by low soil moisture during the late summer and early autumn, is demonstrated to be the most important negative factor followed by the hunting pressure and predation. Demographic and mechanistic factors highlighted in this analysis could be used either for conservation or for controlling populations of the species.