REVIEW: AMPHIBIAN SURVEYS IN FORESTS AND WOODLANDS

Amphibian surveys provide information on the distribution, abundance and habitat requirements of species, and the environmental variables that control diversity. Such information is needed for effective conservation planning and management of forests and woodlands, including monitoring of amphibian populations in a period of apparent global decline. Amphibian surveys can be time-consuming and expensive, and many issues must be addressed to maximize the reliability of the resulting data. Sampling techniques that are effective in one region or habitat type may be less so in another, and a preliminary study comparing different techniques before undertaking a survey may be necessary. Data collected in poorly designed surveys can be unsuitable for statistical analysis, and may sometimes present a misleading picture of the distribution, abundance and habitat requirements of amphibian species. This review examines issues of survey design, assesses past amphibian surveys in forest and woodland habitats, and provides recommendations for planning an amphibian survey. Firstly, the study area and survey aims should be identifi ed, and proposed sampling techniques assessed using relevant literature or a pilot study. Ethical issues associated with proposed sampling techniques should also be considered. The number, size and arrangement of the survey units (e.g. plots, sites or transects) should be sufficient to address the survey aims. The survey units should be systematically surveyed several times with appropriate sampling techniques.

EFFECTS OF CHIGGER MITE (ACARI: TROMBICULIDAE) INFECTIONS ON AMEIVA (SQUAMATA: TEIIDAE) FROM THE ANGUILLA BANK

We examined 152 Ameiva plei from four sites on Anguilla and from Scrub Island, a nearby satellite, and 12 A. corax from Little Scrub Island, another Anguillian satellite, generated indices of condition by dividing mass (g) by SVL (mm), and quantified degrees of eutrombiculid chigger mite infections by measuring the total areas (mm2) of each lizard covered by one or more clusters of mites. Prevalence in infected A. plei (N = 77) varied significantly by site, but frequencies of infected males and females within sites did not differ signifi cantly. Indices of condition of infected and mite-free lizards did not differ significantly, nor was area covered by mites significantly correlated with condition, suggesting that mite infections are relatively asymptomatic. All Ameiva corax were infected, and area covered by mites was not significantly correlated with condition. Indices of condition for A. corax were signifi cantly lower than for infected A. plei, probably refl ecting the poorer condition of lizards occupying a food-deficient habitat.

REPRODUCTION AND HABITAT OF TEN BRAZILIAN FROGS (ANURA)

Basic data on habitat, behavior, and reproduction arelacking for most Neotropical frog species and even highertaxonomic groups (Crump 1974; Haddad and Prado2005), particularly for those restricted to the AtlanticForest. Basic reproductive features are the basis of comparativestudies on evolution of major natural historyfeatures (Harvey and Pagel 1998), such as the interspecific relationship between body size and egg number/size (Salthe and Duellman 1973, Crump 1974, Stearns1992). Here, we present data on habitat, reproductivebehavior and quantitative parameters such as adult sizes,egg numbers/sizes of ten sympatric frogs of an altitudinalAtlantic Forest site in Southeastern Brazil.

WHAT IS THE LENGTH OF A SNAKE?

The way that herpetologists have traditionally measuredlive snakes is by stretching them on a ruler andrecording the total length (TL). However, due to the thinconstitution of the snake, the large number of intervertebraljoints, and slim muscular mass of most snakes,it is easier to stretch a snake than it is to stretch anyother vertebrate. The result of this is that the length ofa snake recorded is infl uenced by how much the animalis stretched. Stretching it as much as possible is perhapsa precise way to measure the length of the specimenbut it might not correspond to the actual length ofa live animal. Furthermore, it may seriously injure a livesnake. Another method involves placing the snake in aclear plexiglass box and pressing it with a soft materialsuch as rubber foam against a clear surface. Measuringthe length of the snake may be done by outlining itsbody with a string (Fitch 1987; Frye 1991). However, thismethod is restricted to small animals that can be placedin a box, and in addition, no indications of accuracy of thetechnique are given. Measuring the snakes with a fl exibletape has also been reported (Blouin-Demers 2003)but when dealing with a large animals the way the tapeis positioned can produce great variance on the fi nal outcome.In this contribution we revise alternative ways tomeasuring a snake and propose a method that offers repeatableresults. We further analyze the precision of thismethod by using a sample of measurements taken fromwild populations of green anacondas (Eunectes murinus)with a large range of sizes.

VOCAL REPERTORY OF TWO SPECIES OF THE LEPTODACTYLUS PENTADACTYLUS GROUP (ANURA, LEPTODACTYLIDAE)

Among frogs, vocalizations play important roles in their social interactions. Herein we describefi ve new types of vocalizations for two foam-nesting species of the Leptodactylus pentadactylusgroup, L. syphax and L. labyrinthicus. Behavioral observations and recordings were done in fourlocalities within the Cerrado biome, at southeast and central Brazil. Before emitting advertisementcalls, males of L. syphax often started producing a sequence of notes, which gradually turned into theadvertisement call. These different notes may be an introductory call, which would serve to preparethe vocal structures for the emission of the high-frequency/amplitude advertisement calls. A male ofL. syphax was emitting advertisement calls when a female approached and started to emit brief andlow-amplitude calls; these vocalizations probably are reciprocation calls. Males of L. labyrinthicusinvolved in agonistic interactions can emit vocal cracks (encounter call) and deep rough sounds (territorialcalls). Five courting males of L. labyrinthicus released screams with their mouth slightly openedin response to the approach of human observers. We conclude that these screams do not representdistress or territorial calls.

RESEARCH PERSPECTIVES:

Whether it is their nocturnal habits, their ability to regenerateentire limbs and tails with functional neurons,or simply their ability to emerge unsinged from a burningyule log, salamanders have long intrigued humansand witches alike. Salamanders are marvelous beasts inmany other ways.

IMMACULATE CONCEPTION, INCUBATION PROTOCOLS, AND EGG CHARACTERISTICS OF THE GANGES SOFTSHELL TURTLE (ASPIDERETES GANGETICUS)

Reproductive biology of Aspideretes gangeticus was studied between 1986 and 2001. Clutchsize averaged 17.9 eggs and ranged between six to thirty-fi ve eggs. Egg length averaged 30.6 mm,egg width averaged 30.22 mm, and egg weight averaged 16.85 g. Clutch volume averaged 253.75ml. No signifi cant difference was observed in clutch size between dry and wet seasons. Of the variousincubation protocols tested, one that involved transitional temperatures of 28º – 31º C, to chilling at15º – 18º C, and then 23º – 26º C resulted in the highest hatching success. Aspideretes gangeticusexhibit two forms of development arrest during incubation, embryonic diapause early in incubation andembryonic aestivation in the latter trimester of incubation. The two Aspideretes gangeticus femalesthat produced clutches for the current study produced eggs with a high fertility percentage throughoutthe fi fteen years for which they stored sperm.

Notes on the Reproductive Biology of the Alabama Red Hills Salamander (Phaeognathus hubrichti )

Living Amphibia exhibit two major life history modes, possession of an aquatic larval stage or direct development, with the latter assumed to be the derived evolutionary condition (Duellman and Trueb 1986, Wake 1989). A small group (n = 20 species) of plethodontid salamanders, the subfamily Desmognathinae, is of great interest because its members display both developmental modes (Marks 1995). For decades the prevailing phylogenetic hypothesis for the group, based upon morphology and habitat, was a monophyletic sequence from the larger, more aquatic species that possessed the longest larval lives to two dwarf terrestrial species with direct development Dunn (1926). This “aquatic to terrestrial” hypothesis remained unchallenged even with the discovery of a new, giant, fossorial species, the Alabama Red Hills Salamander (Phaeognathus hubrichti), that was thought to be a third species with direct development (Highton 1961).Recently, analysis of mtDNA sequences revealed that the terrestrial desmognathines form the three deepest branches in desmognathine phylogeny, compelling the authors to advance an alternative phylogenetic hypothesis that absence of an aquatic larval stage may be ancestral for desmognathines (Titus and Larsen 1996). Their hypothesis rested, however, on details of the developing embryo and hatchlings in the three species with direct development, but critical data on the eggs, hatchlings, and whether larvae exist in P. hubrichti are unavailable.Aspects of the reproductive biology of the rare and secretive Phaeognathus hubrichti are difficult to observe in the field because the species is a burrower. One clutch laid by a female kept in captivity for six years apparently was unfertilized because the eggs failed to develop (Brandon and Moruska 1982). The large size and small number of ripe ovarian oocytes observed in preserved specimens, coupled with the unusual terrestrial burrowing behavior of the species, suggest the absence of an aquatic larval stage (Brandon 1965).On several visits to one ravine in Butler Co., Alabama (31°32’N, 86°45’W) during the spring and summer of 2002, I repeatedly observed a 105 mm SVL gravid female, discovered her eggs, kept them in captivity until they hatched, then returned the female and her clutch alive back into the field. Here I describe the field observations, eggs, embryos, and hatchlings.

Woody and arboreal habitats of the Green Salamander (Aneides aeneus) in the Blue Ridge Mountains

The green salamander (Aneides aeneus) is primarily considered a rock crevice dwelling species. However, many early observations from Kentucky, Tennessee, Virginia, and West Virginia report A. aeneus taken from woody and arboreal habitats. There have been only four published records of A. aeneus using such habitats within the Blue Ridge Disjunct population of southwest North Carolina, northeast Georgia, and northwest South Carolina, and no records since 1952. Here I report two personal observations of A. aeneus using arboreal habitats in North Carolina. Additionally, I report nine observations, made by others, of A. aeneus using woody, arboreal, or otherwise non-rock-crevice habitats in North and South Carolina, including the first non-rock-crevice A. aeneus nesting record for the Blue Ridge. I also speculate that woody and arboreal habitats play a much larger role in the life-history of A. aeneus than generally thought, and that the rarity of A. aeneus is linked to the loss of American Chestnut and old-growth forests.

Arboreal frogs, tank bromeliads and disturbed seasonal tropical forest

We investigated the relationship between arboreal frogs, tank bromeliads and landscape transformation in tropical forests of southeastern Campeche, Mexico. We surveyed frogs in six distinct habitats: slash and burn agriculture, seasonally flooded forest (bajo), aquatic habitats (lagoons and small ponds), second growth upland forest, primary forest and creek habitat using both systematic and non-systematic surveys. The highest species richness of frogs was documented in primary forest and small ponds. In contrast, no frogs were recorded in second growth forest. Similarly, tank bromeliads (Aechmea bracteata) were completely absent from early successional stages and were almost twice as abundant in seasonally flooded forest as in upland forest. The vertical distribution of A. bracteata differed between forest types, and they significantly more abundant in larger diameter trees. We examined 60 tank bromeliads during the peak of the dry season to test their use as refugia by frogs. Approximately 27% of tank bromeliads sampled had arboreal frogs belonging to three species, but 9 species have been recorded as occasional users of bromeliads in the region. There were significantly more frogs on large than on medium-sized bromeliads, and frogs were more abundant on bromeliads higher on host trees, particularly those above 3 m in height. Our results suggest that the loss of tank bromeliads from drier and less structurally complex habitats created by slash and burn agriculture and selective logging results in loss of refugia for arboreal frogs in this seasonal tropical forest. We suggest that Aechmea bracteata be a keystone species in seasonal tropical forest.