Habitat Separation among Three Species of Water Snakes in Northwestern Kentucky

Laurent, Edward J.; Kingsbury, Bruce A

doi:10.1670/0022-1511(2003)037[0229:hsatso]2.0.co;2

Cited by 18 publications

(18 citation statements)

References 14 publications

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“…They are the most distant of any two sampling sites within a region in our study; the Muscatatuck River that lies between them completely lacks a riparian buffer zone, and there is a near complete absence of wetland habitat. Furthermore, the riverbank is steep and thus maintains deep water levels, habitat that is marginal for copperbelly water snakes in other parts of their range (Laurent and Kingsbury 2003).…”

Section: Population Differentiation and Genetic Diversitymentioning

confidence: 99%

Microsatellite variation, population structure, and bottlenecks in the threatened copperbelly water snake

2008

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Habitat loss and isolation is pervasive in the Midwest U.S. Wetlands are experiencing particularly dramatic declines, yet there is a paucity of information on the genetic impacts of these losses to obligate wetland vertebrates. We quantified the genetic variation of extant populations of a shallow wetland specialist and evaluated potential reductions in population size (i.e. bottlenecks) using seven polymorphic microsatellite DNA markers. We analyzed 228 copperbelly water snakes (Nerodia erythrogaster neglecta), representing populations from three states. Moderate genetic differentiation exists among all three regions (F ST = 0.12, P \ 0.001), with evidence for low levels of differentiation within the federally protected Ohio region (F ST = 0.025, P = 0.007), and moderate to strong differentiation within the Indiana region (F ST = 0.23, P \ 0.001). Furthermore, Bayesian clustering (i.e. STRUCTURE) supports the separation of the Indiana sites, both from each other and from all other sampling sites. However, it does not support the separation of the Ohio sites from the Kentucky sites. Differentiation among sampling sites did not appear to be related to geographic distance, but rather depended on the quality of terrestrial corridors used for dispersal. Mode shifts in allele frequencies and excess heterozygosity tests were negative, while M-ratio tests were nearly all positive, indicating the likelihood of historical rather than contemporary population bottlenecks. However, potential subspecific intergradation in the Kentucky region may have artificially lowered the M-ratio, and we suggest caution when using the M-ratio approach if intergradation is suspected. Our results have conservation implications for wetland management and management of the copperbelly populations, and emphasizes the importance of protecting wetland complexes.

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Section: Population Differentiation and Genetic Diversitymentioning

confidence: 99%

Microsatellite variation, population structure, and bottlenecks in the threatened copperbelly water snake

2008

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“…Thus, an updated monitoring of the egg collections by the commercial crocodile ranchers would be necessary to establish whether this activity was still sustainable, given the reduced population size of the MFNP crocodiles compared to some decades ago. Unsurprisingly, the crocodiles showed an uneven preference for some habitat types (e.g., Laurent & Kingsbury 2003), as was also typically observed in Afrotropical reptiles (e.g., Muhigwa 1998;Eniang et al 2015) including crocodiles (e.g., Cott 1961;Magnusson 1985;Luiselli et al 2012). Outside the water habitat, grassy banks, islands, river mouths and sandy banks constituted about 47% of the habitats utilised by crocodiles, thus showing that these habitats were very important and should be appropriately preserved if we are to appropriately protect the crocodile population.…”

Section: Discussionmentioning

confidence: 99%

Population surveys of Nile crocodiles (Crocodylus niloticus) in the Murchison Falls National Park, Victoria Nile, Uganda

Behangana¹,

Lukwago²,

Dendi³

et al. 2017

European Journal of Ecology

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Abstract1. A 12-month-long survey (April 2013 to March 2014) for Nile crocodiles (Crocodylus niloticus) was conducted along a section of the Victoria Nile/Ramsar site of Murchison Falls National Park, in order to update the historic information on crocodile populations in the area, locating nesting areas, determining seasonality patterns and habitat use, and assess the current abundance and the population size trends since the 1960s. The methods employed included visual encounter surveys, transect counts and opportunistic methods, by using boats. 2. In general, there were diurnal and seasonal fluctuations in the number of crocodile sightings. The crocodile sightings peaked between the months of June and August, with the highest mean number of sightings encountered on any single day being 67 (in July 2013), and the second peak was between January and March with the highest mean of 118 recorded in January 2014. The second peak also coincided with the crocodile breeding season. This clearly shows that the distribution of the sub-population sampled followed a climatic regime. 3. Crocodiles were observed most frequently in water (37%). Grassy banks, islands, river mouths and sandy banks constituted about 47% of the habitats utilised by the crocodile population. Although basking was the most frequent type of activity performed by crocodiles (50%) over the entire survey period, their key activities varied significantly from month to month. Nesting was very visible during the last quarter of the year and the first quarter of the New Year. 4. There was a clear decline of the abundance of crocodiles in this population between 1960s and nowadays. This declining trend was obvious also taking into account the various survey methodologies employed over the decades.

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“…In general, we would predict that northern watersnakes will be eating fishes according to their abundance and availability in the habitat unless ecological or behavioral factors alter the probability of some fish from being encountered and captured. Some northern watersnake populations are of conservation concern (King et al 2006) but many localities have large populations of northern watersnakes (Bauman and Metter 1975, Laurent and Kingsbury 2003, Gibbons and Dorcas 2004 and as long as there is prey present, the adaptable northern watersnake will likely be present in aquatic areas throughout the species' range. …”

Section: Discussionmentioning

confidence: 99%

“…While many factors may also contribute to watersnake coexistence, including landscape effects (Steen et al 2014), microhabitat differences (Laurent and Kingsbury 2003) and interactions of temporal, spatial and dietary effects (Vitt 2001, differences in diet likely best explain coexistence as sympatric North American watersnakes commonly partition their trophic niches (Luiselli andRugiero 1991, Luiselli 2006).…”

Section: Discussionmentioning

confidence: 99%

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Dietary resource utilization patterns and head morphology among three sympatric watersnake species.

Perkins¹

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Habitat Separation among Three Species of Water Snakes in Northwestern Kentucky

Cited by 18 publications

References 14 publications

Microsatellite variation, population structure, and bottlenecks in the threatened copperbelly water snake

Microsatellite variation, population structure, and bottlenecks in the threatened copperbelly water snake

Population surveys of Nile crocodiles (Crocodylus niloticus) in the Murchison Falls National Park, Victoria Nile, Uganda

Dietary resource utilization patterns and head morphology among three sympatric watersnake species.

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