Survival and habitat use of sympatric lagomorphs in bottomland hardwood forests

Abstract

Lagomorphs are important consumers and prey in ecosystems worldwide, but have declined due to land use changes and habitat loss, and such losses may be exacerbated for specialist species. We compared survival and habitat use of two closely related lagomorphs, the swamp rabbit (Sylvilagus aquaticus (Bachman, 1837)), a bottomland hardwood (BLH) forest specialist, and the eastern cottontail (Sylvilagus floridanus (J. A. Allen, 1890)), a habitat generalist. We tested whether survival and habitat use differed between radio-collared swamp rabbits (n = 129) and eastern cottontails (n = 72) monitored during December 2009 – December 2013 in southern Illinois. We found interactive effects of species and season on survival rates: swamp rabbits had higher annual survival (0.37 ± 0.05 (estimate ± SE)) than did cottontails (0.20 ± 0.05), but this difference occurred primarily during the growing season. Swamp rabbits were located closer to watercourses in areas characterized by higher basal area and more mature BLH forest cover compared with eastern cottontails. Our results suggest that BLH forests may be marginal habitat for cottontails and indicate predation as the primary cause of mortality for both species. Swamp rabbits use of early-successional BLH forest suggests that restoration efforts have been successful. However, as specialists, swamp rabbits remain restricted to a narrow band of bottomlands near watercourses and may benefit from improved upland cover that serves as refugia from flooding.

A landscape genetic analysis of swamp rabbits (Sylvilagus aquaticus) suggests forest canopy cover enhances gene flow in an agricultural matrix

“…However, there is also a positive relationship between canopy closure and swamp rabbit latrine sites (Zollner et al 2000a) and detection probabilities of swamp rabbits in the northern fringe of their range (Scharine et al 2011; but see Smyth et al 2007). Additionally, despite a similar affinity for shrub cover, swamp rabbits use more mature forest than sympatric eastern cottontails (Crawford et al 2018). These results and those of our study raise the possibility that canopy cover and mature forest are important for swamp rabbits at the landscape scale, particularly at the northern fringe of the swamp rabbit range (Dumyahn et al 2015).…”

“…Most habitat studies of swamp rabbits measure canopy cover at the finer, microhabitat scale, generally within bottomland hardwood forests or adjacent uplands, and distinguish between mature forest canopy cover and understory vegetation (e.g., Zollner et al 2000a;Scharine et al 2009;Vale and Kissell 2010;Dumyahn et al 2015;Crawford et al 2018). Although the methods used to develop the National Land Cover Database tree canopy cover data distinguished forest canopy from nonforest cover types (Huang et al 2001), these methods did not distinguish early successional from mature forest and understory structure was not considered.…”

“…All sites known to be occupied in previous surveys (Kjolhaug et al 1987;Porath 1997;Woolf and Barbour 2002;Scharine et al 2009) or predicted to have highly suitable habitat for swamp rabbits based on models (Robinson et al 2016) were trapped or surveyed for fecal pellets at least once during December-March 2004-2011. We analyzed unique genotypes primarily from tissue biopsies taken from trapped rabbits (n = 113) captured December-March 2004(Scharine et al 2011, Crawford et al 2018; Institutional Animal Care and Use Committee at Southern Illinois University Carbondale protocol 06-035). Hunter harvests (n = 13) and a road kill (n = 1) collected from 2006 to 2011 served as additional samples.…”

“…Additionally, little prior knowledge exists from which to develop testable hypotheses regarding landscape connectivity. Those studies that have used radiotelemetry to document movements of swamp rabbits have focused on home ranges (Kjolhaug and Woolf 1988;Zollner et al 2000b;Dumyahn and Zollner 2010;Vale and Kissell 2010;Crawford et al 2018) and none have discerned movements associated with dispersal. Thus, the aim of our study was to determine which landscape features are related to swamp rabbit gene flow and could influence landscape connectivity at the northern fringe of their range.…”

The potential of marginal coastal nursery habitats for the conservation of a culturally important Caribbean marine species

“…Despite being of lower quality, marginal habitats can play a role in the persistence of species in situations where the core habitat is under substantial disturbance and where most of the individuals inhabiting this key area are under threat of disappearing (Wintle et al, 2019). Such marginal habitats can offer protection against threats such as dramatic stochastic environmental variations (e.g., floods for birds, Jankowiak &Ławicki, 2014 andlagomorphs, Crawford, Nielsen, &Schauber, 2018; groundwater seeps during drought conditions for freshwater fishes, Vrdoljak & Hart, 2007) but also habitat degradation by human activities (e.g., roadside grassland for native bees, Hopwood, 2008). However, this type of protection is only efficient on the long term if the individuals are able to emigrate from marginal habitats to repopulate the core habitats (Kawecki, 2008;Kerley, Kowalczyk, & Cromsigt, 2012).…”