Patterns of Species Diversity of Snake Community Assemblages, with Data on Two Everglades Snake Assemblages

Dalrymple, George H.; Bernardino, Frank S.; Steiner, Todd; Nodell, Robert J.

doi:10.2307/1446600

Cited by 8 publications

(3 citation statements)

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“…Perhaps the most widely utilized categories for snake habitat use include fossorial, terrestrial, aquatic, semiaquatic, arboreal and semiarboreal, or some subset of these (e.g. Johnson 1955;Shine 1983;Guyer & Donnelly 1990;Dalrymple et al 1991;Lindell 1994;Vidal et al 2000).…”

Section: A T E G O R I Z I N G G R a V I T A T I O N A L H A B I T mentioning

confidence: 99%

The evolution of tail length in snakes associated with different gravitational environments

2015

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Summary Gravity imposes potentially important constraints on blood circulation in tall or elongate animals during upright posture or climbing. Upright postures create vertical gradients of gravitational (=hydrostatic) pressures within circulatory vessels. In terrestrial animals, this pressure potentially induces blood pooling and oedema in dependent (inferior) tissues and, secondarily, decreases blood volume reaching the head and vital organs. Arboreal snakes exhibit a suite of adaptations for countering the effects of gravity on blood circulation, including relatively non‐compliant tissue compartments in the tail. However, patterns of tail length related to arboreal habitats and gravity have not been previously studied. Here, we test the hypothesis that arboreal snakes have relatively longer tails than non‐climbing species, and we interpret the results within the context of adaptation to gravity stress. Length data were obtained for 226 snake species, 139 genera and 15 snake families assigned to three broad gravitational habitat categories (G‐habitats: stenotopically arboreal, eurytopically arboreal/terrestrial and non‐scansorial). We constructed a composite phylogenetic tree and quantified the relationships between snake morphology and G‐habitat using conventional regression analysis of species data and regressions of phylogenetically independent contrasts. Mean relative tail length (RTL) increased and mean relative snout‐vent length decreased with increasing arboreality among the three G‐habitats. However, mean total body length (TL) was not different between the two arboreal G‐habitats. Snakes with longer RTLs have a higher percentage of elongate blood vessels contained within the relatively non‐compliant integument of the tail, which mitigates postural blood pooling experienced during climbing. TL in adult female arboreal snakes is hypothesized to be an evolutionary trade‐off between demands for a longer tail to enhance cardiovascular performance and the length of body cavity to provide space for young. Our results complement previous studies correlating RTL with arboreal habitat use, in addition to physiological experiments quantifying the effects of gravity on blood flow in snakes. These results provide evidence that long RTLs of arboreal snakes function, at least in part, as an adaptive response to cardiovascular stresses on blood circulation imposed by gravity. Selection on tail length related to other factors seems less likely, but is in need of further investigation.

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Section: A T E G O R I Z I N G G R a V I T A T I O N A L H A B I T mentioning

confidence: 99%

The evolution of tail length in snakes associated with different gravitational environments

2015

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“…Some researchers surveyed the snake communities using individual observation along the established transect lines, or using snakes captured by basket traps with no return valves, or pitfall traps using drift fences, or drift fences and cover objects (Akani et al, 1999;Nussbaum et al, 1999;Tu and Wang, 2000;Luiselli and Akani, 2002). On the other hand, other researches investigated snake communities both walking and by road cruising in an automobile (Tu and Wang, 2000;Anaki et al, 2002), or only by road cruising in an automobile (Dalrymple et al, 1991). In this survey, a car was driven along the road to survey the snake fauna during the peak of activity for nocturnal snakes (unpubl., T.H.…”

Section: Discussionmentioning

confidence: 99%

“…Fragmentation of habitat not only may eliminate large predators that require larger habitat areas than smaller animals (Soulé et al, 1988), but may also produce high mortality rates associated with frequent encounters of wildlife (in our case, snakes) with humans (Litvaitis et al, 1996;Victoria and Litvaitis, 2001), as well as many animals being killed on roads (Dalrymple et al, 1991;Rosen and Lowe, 1994;Bonnet et al, 1999;Tu and Wang, 2000;Akani et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Ecological patterns of distribution on gradients of elevation and species diversity of snakes in southern Taiwan

Lee

2005

Amphib Reptilia

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The study was conducted in southern Taiwan, along a road traversing the study area from 287 to 1680 m a.s.l. from May to October 2003 to investigate the distribution patterns and species diversity of the snakes. A total of 69 individual snakes belonging to 16 species were recorded. The Shannon's index and evenness index of the full study area were 2.4337 and 0.8777, respectively. Moreover, evenness index was 401 to 700 m > 1001 to 1300 m > 701 to 1000 m > 1301 to 1600 m altitudinal zone. The Shannon's index, D MG , and the reciprocal form of the Berger-Parker index (1/d) were 1001 to 1300 m > 401 to 700 m > 701 to 1000 m > 1301 to 1600 m altitudinal zone. Thirty-seven snakes were found in natural forest, 12 in plantation forest, 8 in secondary forest, and 12 in agricultural lands. I concluded that the highest species richness and diversity are found in mid-altitudinal mountains in southern Taiwan.

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Vertebrate Faunal Diversity of Longleaf Pine Ecosystems

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Springer Series on Environmental Management

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Patterns of Species Diversity of Snake Community Assemblages, with Data on Two Everglades Snake Assemblages

Cited by 8 publications

References 0 publications

The evolution of tail length in snakes associated with different gravitational environments

The evolution of tail length in snakes associated with different gravitational environments

Ecological patterns of distribution on gradients of elevation and species diversity of snakes in southern Taiwan

Vertebrate Faunal Diversity of Longleaf Pine Ecosystems

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