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Population dynamics of eastern cottontail rabbits in an urban park in Chicago, Illinois: population size estimates and population density, mean body mass, annual survival, and capture probability
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Eastern cottontail rabbits (Sylvilagus floridanus) are common, conspicuous denizens of urban environments. They are associated with human-wildlife conflict due to vegetation damage. Prior to this study, population dynamics of this species in urban environments remained largely uncharacterized. For three consecutive winters, we used classic field ec...
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... overlaid this visualization of capture rate on top of an aerial map of the study area obtained from the Illinois Natural Resources Geospatial Data Clearing House (University of Illinois at Urbana-Champaign 2004). (Table 1). ...
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... estimated annual apparent survival as 30.4±12.9 % SE and capture probability as 56.6± 20.8 % SE between 2010 and 2011 using the POPAN model in the program MARK (Table 1). In the most parsimonious implementation of the POPAN model as determined by Akaike informa- tion criterion, ĉ was equal to 1, indicating that the data was not overdispersed ( White and Burnham 1999). ...
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... SD, ranging from 0.8 kg to 1.6 kg. We used a 2-tailed t-test to compare masses of rabbits in 2011 and 2012 (Table 1). Body masses in 2012 were greater than body masses in 2011 (P=0.02, ...
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... population density in our study site was 16.3 rabbits/ha in 2010, 10.0 rabbits/ha in 2011, and 9.4 rabbits/ha in 2012 (Table 1). For comparison, in an undeveloped habitat in Michigan in the fall, rabbit densities were 0.08-0.35 ...
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... apparent survival of adult rabbits in our system was 30.4±12.9 % SE (Table 1), which is similar to annual survival of populations in natural areas. Haugen (1942) deter- mined that in undeveloped settings, approximately 20 % of juvenile rabbits survived until the fall in the year of their birth. ...
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... masses of rabbits in 2012 were greater than in 2011 (Table 1). Additionally, year influenced frequency of weight categories as the mode shifted upwards from 1.1 kg in 2011 (n=16) to 1.2 kg in 2012 (n=18). ...
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... year influenced frequency of weight categories as the mode shifted upwards from 1.1 kg in 2011 (n=16) to 1.2 kg in 2012 (n=18). The shift upward in body mass from 2011 to 2012 (Table 1) may have resulted from extreme weather. In 2011, Chicago experienced the third largest blizzard on record with 51 cm of snow (Chicago Weather Center 2011). ...
Citations
... Today, EC is found throughout New England (Buffum et al. 2015). The reason EC has been successful at establishing outside of its native range is the ability to thrive in a wide variety of habitats, even highly urbanized, making it a habitat generalist (Chapman and Litvaitis 2003;Hunt et al. 2014). However, studies of EC habitat selection in their introduced range and at different spatial scales have found evidence of habitat preference (Bond et al. 2002;Bertolino et al. 2011). ...
Introduced species competing with native species can decrease the density and abundance of native species, causing concern for the persistence of native species populations. The presence of the introduced eastern cottontail (Sylvilagus floridanus—EC) in habitat patches with the imperiled New England cottontail (Sylvilagus transitionalis—NEC) can lead to interspecific competition. However, the degree to which this interspecific competition leads to changes in NEC relative abundance is unknown. We used open 2 species N-mixture models with directional interactions to determine how EC relative abundance at a site influences NEC relative abundance and how covariates affected both species’ relative abundance. We found that EC relative abundance had a strong negative influence on NEC relative abundance, with an estimated effect of − 0.163, providing further evidence of interspecific competition between the 2 species. We found evidence of resource partitioning between the 2 species, where NEC relative abundance was positively influenced and EC relative abundance was negatively influenced by vegetation heights of 0.5 to < 2.5 m. Overall, our results demonstrate the consequences of EC presence in native lagomorph ranges and the utility of N-mixture models for assessing the magnitude of interspecific competition between introduced and imperiled species.
... New England cottontail occupancy and colonization positively responded to the amount of shrublands within the landscape and weakly responded to forest regeneration, the vegetation type most commonly created by management actions for the species. New England cottontail colonization probability was low at both the patch and landscape scale, and lower than extinction probabilities, (Hunt et al. 2014) and areas recently experiencing land cover change (Hidalgo-Mihart et al. 2017). In New England, the 2 species often co-occur in young forests and shrublands, both selecting for densely vegetated microhabitat (O'Connor 2015). ...
In response to the widespread threat of habitat loss, managers of imperiled species commonly focus on restoring habitat to encourage species establishment (i.e., the field of dreams hypothesis). Habitat management strategies for the rare New England cottontail (Sylvilagus transitionalis) have largely followed the field of dreams hypothesis, focusing on increasing the area of young and regenerating forest throughout the species' range to increase populations of the species. Recently researchers indicated that these practices may not be as effective when the introduced eastern cottontail (Sylvilagus floridanus) co-occupies patches with the New England cottontail. Using data from the New England Cottontail Regional Monitoring Program collected in Connecticut, USA, from 2016–2020 and geospatial data to create dynamic occupancy models, we determined how both patch and landscape characteristics influence New England cottontail and eastern cottontail occupancy patterns. We ran 4 dynamic occupancy models: 1 at the patch scale and 1 at the landscape scale for each species. Large patches and short interpatch distances increased both species' occupancy patterns more than vegetation height <2.5 m. New England cottontail occupancy and colonization positively responded to the amount of shrublands within the landscape and weakly responded to forest regeneration, the vegetation type most commonly created by management actions for the species. New England cottontail colonization probability was low at both the patch and landscape scale, and lower than extinction probabilities, suggesting the current landscape may not be sufficient to allow metapopulations to persist. Overall, our results indicate that solely focusing on habitat restoration, or applying the field of dreams hypothesis, to conserve New England cottontail, a species that is area dependent, dispersal limited, and threatened by an introduced competitor, does not promote species persistence on the landscape.
... Increased abundance in disturbed landscapes is likely a primary driver, since the relative abundance model estimated the human disturbance effect to be approximately one-third the magnitude of that from the primary model ( Fig. 2 A-E and Table 1). Resource subsidies such as crops often elevate the abundance of wildlife species (17,18,22), including at least several considered in our analysis (28)(29)(30). With greater numbers of individual animals, there is less space and time per capita to be shared. ...
Human disturbance may fundamentally alter the way that species interact, a prospect that remains poorly understood. We investigated whether anthropogenic landscape modification increases or decreases co-occurrence-a prerequisite for species interactions-within wildlife communities. Using 4 y of data from >2,000 camera traps across a human disturbance gradient in Wisconsin, USA, we considered 74 species pairs (classifying pairs as low, medium, or high antagonism to account for different interaction types) and used the time between successive detections of pairs as a measure of their co-occurrence probability and to define co-occurrence networks. Pairs averaged 6.1 [95% CI: 5.3, 6.8] d between detections in low-disturbance landscapes (e.g., national forests) but 4.1 [3.5, 4.7] d between detections in high-disturbance landscapes, such as those dominated by urbanization or intensive agriculture. Co-occurrence networks showed higher connectance (i.e., a larger proportion of the possible co-occurrences) and greater proportions of low-antagonism pairs in disturbed landscapes. Human-mediated increases in species abundance (possibly via resource subsidies) appeared more important than behavioral mechanisms (e.g., changes in daily activity timing) in driving these patterns of compressed co-occurrence in disturbed landscapes. The spatiotemporal compression of species co-occurrences in disturbed landscapes likely strengthens interactions like competition, predation, and infection unless species can avoid each other at fine spatiotemporal scales. Regardless, human-mediated increases in co-occurrence with-and hence increased exposure to-predators or competitors might elevate stress levels in individual animals, with possible cascading effects across populations, communities, and ecosystems.
... To assess how characteristics of urban environments influenced diel activity of urban wildlife mammals, we calculated site-level predictor variables within a fixed-radius buffer around each sampling site. Fixed-radius buffers varied in size among species and were based on the typical home range of each species: 500 m fixed-radius buffer for eastern cottontail (Hunt et al., 2013), Virginia opossum (Fidino et al., 2016;Wright et al., 2012), and white-tailed deer (Etter et al., 2002); 1 km fixed-radius buffer for striped skunk (Weissinger et al., 2009) and raccoon (Rosatte, 2000), and 1.5 km fixed-radius buffer for coyote (Gehrt et al., 2009;Riley et al., 2003), red fox (Mueller et al., 2018), and bobcat (Riley et al., 2003). In our analysis, we included variables calculated within each species' fixed-radius buffer that described two contrasting characteristics of urban ecosystems, the natural and the humanbuilt environment (Supplementary file 1d). ...
Time is a fundamental component of ecological processes. How animal behavior changes over time has been explored through well-known ecological theories like niche partitioning and predator-prey dynamics. Yet, changes in animal behavior within the shorter 24-hour light-dark cycle have largely gone unstudied. Understanding if an animal can adjust their temporal activity to mitigate or adapt to environmental change has become a recent topic of discussion and is important for effective wildlife management and conservation. While spatial habitat is a fundamental consideration in wildlife management and conservation, temporal habitat is often ignored. We formulated a temporal resource selection model to quantify the diel behavior of eight mammal species across ten U.S. cities. We found high variability in diel activity patterns within and among species and species-specific correlations between diel activity and human population density, impervious land cover, available greenspace, vegetation cover, and mean daily temperature. We also found that some species may modulate temporal behaviors to manage both natural and anthropogenic risks. Our results highlight the complexity with which temporal activity patterns interact with local environmental characteristics, and suggest that urban mammals may use time along the 24-hour cycle to reduce risk, adapt, and therefore persist, and in some cases thrive, in human-dominated ecosystems.
... The higher level of variation in genotype and phenotype of introduced eastern cottontail also has been documented in Maryland where over 200,000 eastern cottontail were translocated to the state (Chapman and Morgan 1973). Eastern cottontail is a habitat generalist that can be found in a wide variety of habitats that range from rural to urban (Hunt et al., 2014) and span from North to South America (Chapman et al., 1980). The introduction of eastern cottontail may represent one of the causes that accelerated the decrease in number of New England cottontail and loss of their habitat. ...
The environment plays an important role in the movement of individuals and their associated genes among populations, which facilitates gene flow. Gene flow can help maintain the genetic diversity both within and between populations and counter the negative impact of genetic drift, which can decrease the fitness of individuals. Sympatric species can have different habitat preferences, and thus can exhibit different patterns of genetic variability and population structure. The specialist-generalist variation hypothesis (SGVH) predicts that specialists will have lower genetic diversity, lower effective population sizes (Ne), and less gene flow among populations. In this study, we used spatially explicit, individual-based comparative approaches to test SGVH predictions in two sympatric cottontail species and identify environmental variables that influence their gene flow. New England cottontail (Sylvilagus transitionalis) is the only native cottontail in the Northeast US, an early successional habitat specialist, and a species of conservation concern. Eastern cottontail (S. floridanus) is an invasive species in the Northeast US and a habitat generalist. We characterized each species’ genomic variation by developing double-digest Restriction-site Associated DNA sequence single nucleotide polymorphism markers, quantified their habitat with Geographic Information System environmental variables, and conducted our analyses at multiple scales. Surprisingly, both species had similar levels of genetic diversity and eastern cottontail’s Ne was only higher than New England cottontail in one of three subregions. At a regional level, the population clusters of New England cottontail were more distinct than eastern cottontail, but the subregional levels showed more geographic areas of restricted gene flow for eastern cottontail than New England cottontail. In general, the environmental variables had the predicted effect on each species’ gene flow. However, the most important environmental variable varied by subregion and species, which shows that location and species matter. Our results provide partial support for the SGVH and the identification of environmental variables that facilitate or impede gene flow can be used to help inform management decisions to conserve New England cottontail.
... Because rabbits are an important part of coyotes' diet, along with small rodents, coyotes exert top-down pressures to control their populations (Poessel et al., 2017). Cottontail rabbits have high reproductive rates that result in rapidly growing populations that interact, directly or indirectly, with humans in gardens, yards, parks and other green spaces throughout city limits (Hunt et al., 2014;Baker et al., 2015). We conducted a non-invasive camera survey to investigate the vigilance behavior of rabbits in response to anthropogenic and natural threats. ...
Rapid urbanization coupled with increased human activity induces pressures that affect predator-prey relations through a suite of behavioral mechanisms, including alteration of avoidance and coexistence dynamics. Synergisms of natural and anthropogenic threats existing within urban environments exacerbate the necessity for species to differentially modify behavior to each risk. Here, we explore the behavioral response of a key prey species, cottontail rabbits (Sylvilagus floridanus), to pressures from humans, domestic dogs, and a natural predator, coyotes (Canis latrans) in a human-dominated landscape. We conducted the first camera survey in urban parks throughout Detroit, Michigan in 2017–2020 to assess vigilance response corresponding to a heterogeneous landscape created from variation in the occupancy of threats. We predicted a scaled response where cottontail rabbits would be most vigilant in areas with high coyote activity, moderately vigilant in areas with high domestic dog activity, and the least vigilant in areas of high human activity. From 8,165 independent cottontail rabbit detections in Detroit across 11,616 trap nights, one-third were classified as vigilant. We found vigilance behavior increased with coyote occupancy and in locations with significantly high domestic dog activity, but found no significant impact of human occupancy or their spatial hotspots. We also found little spatial overlap between rabbits and threats, suggesting rabbits invest more in spatial avoidance; thus, less effort is required for vigilance. Our results elucidate strategies of a prey species coping with various risks to advance our understanding of the adaptability of wildlife in urban environments. In order to promote coexistence between people and wildlife in urban greenspaces, we must understand and anticipate the ecological implications of human-induced behavioral modifications.
... This species has been introduced to Italy from North America for hunting purposes (Dori et al., 2019); it is mostly a solitary species, although small groups can be observed at low levels of disturbance. Eastern cottontails can also thrive in urban areas, and several urban populations occur both in the native and in the introduced range (Baker et al., 2015;Hunt et al., 2014;Santini et al., 2019). Lord (1961Lord ( , 1964 reported that the activity of Eastern cottontails peaks at dusk and dawn, with inactive animals concealing in the vegetation during daytime. ...
The COVID-19 pandemic zoonosis has determined extensive lockdowns worldwide that provide an unprecedented opportunity to understand how large-scale shifts of human activities can impact wildlife. We addressed the impacts of the COVID-19 lockdown on wildlife in Italy, the first European country that performed a countrywide lockdown, and identified potentially beneficial and negative consequences for wildlife conservation and management. We combined a qualitative analysis of social media information with field data from multiple taxa, data from citizen science projects, and questionnaires addressed to managers of protected areas. Both social media information and field data suggest that a reduction of human disturbance allowed wildlife to exploit new habitats and increase daily activity. The field data confirmed some positive effects on wildlife conservation, such as an increase in species richness in temporarily less-disturbed habitats, a higher breeding success of an aerial insectivorous bird, and reduction of road-killing of both amphibians and reptiles. Despite some positive effects, our data also highlighted several negative impacts of the COVID-19 crisis on wildlife. The lower human disturbance linked to lockdown was in fact beneficial for invasive alien species. Results from questionnaires addressed to managers of protected areas highlighted that the COVID-19 lockdown interrupted actions for the control of invasive alien species, and hampered conservation activities targeting threatened taxa. Furthermore, the reduction of enforcement could cause a surge of illegal killing of wildlife. The COVID-19 crisis, besides having deep socioeconomic impacts, might profoundly affect wildlife conservation, with potentially long-lasting effects.
... Eastern cottontail rabbits have the ability to thrive in urban and suburban environments, including parks, gardens, and city landscapes, frequently leading to humanwildlife conflicts (Chapman and Flux 1990;Messmer 2009). Interactions with companion animals and lawnmowers often lead to injuries and presence of nests in flowerbeds commonly leads to human inconvenience and displacement, making the ECR a common species presented to wildlife rehabilitation centers in their range (Hunt et al. 2014). ...
... (Griffin and Holt 2001;Abrahamian and Goldstein 2011). It is likely that many of these fatal integument abnormalities occurred secondary to human or domestic animal-wildlife conflicts, as well as wounds from predators, which have been previously documented as common reasons for presentation to a wildlife clinic setting (Hunt et al. 2014). Wildlife medical clinics presented with orphaned ECRs suffering from integumentary abnormalities on initial examination should consider aggressive antimicrobial protocols or potentially reexamine euthanasia guidelines when considering the poor survival status of this group. ...
Orphaned eastern cottontail rabbits (ECRs; Sylvilagus floridanus) often present to wildlife clinics within their geographic range and require considerable dedication of time and resources. The objective of this analytical cross-sectional study was to assess initial examination findings to be used as prognostic indicators for orphaned neonatal and juvenile ECRs. The medical records of the University of Illinois Wildlife Medical Clinic were searched for ECRs presenting between 2012 and 2018. This criterion identified 1,256 ECRs that were then classified as survivors (survived and released) or as nonsurvivors (euthanized or natural death) within 72 h of admission. Presenting weight, body system abnormalities, hydration status, intervention prior to presentation, and singleton versus group presentation were categorically recorded for each individual ECR. The data were modeled using a series of logistic regression models fitted using the general linear model. Individuals were significantly more likely to be nonsurvivors if they presented as singletons ( P<0.0001), presented with moderate/severe ( P<0.001) or mild integumentary signs ( P=0.0261), presented with multi-organ disease ( P<0.001), presented with neurologic signs ( P<0.0003), or had treatment provided prior to presentation ( P=0.031). Factors that did not predict survival status in ECRs included body weight (P=0.210), presence of respiratory signs ( P=0.674), and presence of dehydration ( P=0.356).These findings may be used at wildlife medical clinics to make triage criteria for euthanasia as well as dedicate limited funds and labor to cases with the best prognosis for survival.
... There is currently limited information about urban rabbits. In the Midwestern United States, Hunt et al. (2014) reported higher population densities of eastern cottontail rabbits (Sylvilagus floridanus) in a Chicago urban park compared to populations in undeveloped areas (hereafter, natural), and in Missouri, Jones et al. (2016) found that cottontails selected urban cover over neighboring forest fragments, likely to avoid coyotes. Lastly, in fragmented landscapes near Los Angeles, California, desert cottontails (S. audubonii) and brush rabbits (S. bachmani) occurred in both natural and urban areas. ...
Mammals are known to vary in their sensitivity to urbanization. In heavily urbanized southern California, bobcats (Lynx rufus) prey on rabbits (Sylvilagus spp.) that forage for lush vegetation in developed areas. We collected data on the density of rabbits in adjacent urban and natural areas using visual line surveys. We also measured habitat use for seven GPS-collared female bobcats to determine if bobcats selected areas with higher rabbit densities. Estimated rabbit densities did not vary between urban, urban edge, and natural areas during wet or dry seasons, reflecting their consistent presence across the landscape. During daytime and crepuscular hours, bobcats used natural coastal sage scrub and grassland habitats more frequently (76-84% of the time) than urban areas. Conversely, at night, bobcats decreased their use of coastal sage scrub and doubled their time in urban areas. In summary, we found that rabbits were present across the landscape, and bobcats are likely selecting urban areas at night to prey on rabbits and avoid people.
... Housing density was also included as it represents the inherent human element of urban ecosystems (Foley et al., 2005;Grimm et al., 2008). We chose a 500 m radius because it encompasses the home range of eastern cottontail (Hunt et al., 2014) and the majority of white-tailed deer home range (Etter et al., 2002) without creating significant overlap between independent sampling sites (Gallo et al., 2017). We calculated these metrics using QGIS ver 2.14 (QGIS Development Team, 2009). ...
... It could also be that coyote pose less of a risk to eastern cottontail due to a hyperabundance of prey items (Brown & Kotler, 2007). Eastern cottontails and other small-bodied mammals have high intrinsic growth rates (Feldhamer et al., 2003), and eastern cottontails do exist in high densities within smaller, isolated urban habitat patches (Hunt et al., 2014). At high levels of prey density, coyotes could become satiated and a fear-driven system would switch to a mortality-driven system (Brown & Kotler, 2007). ...
Urbanization is considered the fastest growing form of global land‐use change and can dramatically modify habitat structure and ecosystem functioning. While ecological processes continue to operate within cities, urban ecosystems are profoundly different from their more natural counterparts. Thus, ecological predictions derived from more natural ecosystems are rarely generalizable to urban environments.
In this study, we used data from a large‐scale and long‐term camera trap project in Chicago IL, USA, to determine whether urbanization alters predator‐avoidance behaviour of urban prey species.
We studied three behavioural mechanisms often induced by the fear of predation (spatial distribution, daily activity patterns and vigilance) of white‐tailed deer (Odocoileus virginianus) and eastern cottontail (Sylvilagus floridanus) when coyote (Canis latrans)—an urban apex predator—was present.
We found no evidence of spatial segregation between coyote and either prey species. Furthermore, neither white‐tailed deer nor eastern cottontail changed their daily activity or increased vigilance in urban areas when coyotes were present. Eastern cottontail, however, had their uppermost level of vigilance in highly urban sites when coyotes were absent.
Our study demonstrates that predator–prey dynamics might be modified in urban ecosystems—moving from what is traditionally thought of as a two‐player system (predator and prey) to a three‐player system (predator, prey and people).
