Herpetological Assemblages in Tropical Forests of the Taguibo Watershed, Butuan City, Eastern Mindanao, Philippines

Despite the abundant data on habitat use of Vipera ammodytes, most studies are purely descriptive, merely listing the habitats in which the species is most often found. More complete studies evaluating the habitat preference of the species are lacking. The intraspecific variation (i.e., interpopulation or seasonal) in habitat and microhabitat utilization of the species also remains a poorly studied topic. In the current study, we assessed the general patterns of habitat and microhabitat use of V. ammodytes and their interpopulation and seasonal variations, based on habitat/microhabitat availability. To achieve that, we studied five different populations along a latitudinal gradient in western Bulgaria. In all of the studied areas, V. ammodytes showed a clear preference for various stony and rocky habitats and microhabitats, overgrown with herbaceous and shrub vegetation, while it avoided bare habitats, dark deciduous forests as well as cultivated agricultural lands. There were clear interpopulation and seasonal variations in habitat and microhabitat preference and spatial niche utilization. Our results suggest that habitat and microhabitat use of V. ammodytes depend on a combination of many factors such as season, locally specific characteristics like habitat structure and availability, population dynamics, food availability, physical and microclimatic conditions, and possibly on the extent of the interspecific competition.

The Leyte Sab-a Basin Peatland (LSBP) is a unique wetland ecosystem that is an important refuge for biodiversity. However, the diversity of wildlife communities in peatland ecosystems, particularly herpetofauna (amphibians and reptiles), remains poorly understood. Therefore, the present study provides preliminary accounts of herpetofauna's occurrence, endemicity, habitat, and microhabitat use in LSBP. The field surveys in the peatland have yielded 39 herpetofauna species, comprising 13 frogs, 13 lizards, 12 snakes, and one turtle. Records from a previous study revealed a total of 44 herpetofauna species known to occur in peatland. A threatened species documented in the peatland is the Mindanao Fanged Frog (Limnonectes magnus Stejneger), which is already classified as near threatened based on the IUCN Red List of Threatened Species. The overall herpetofaunal endemicity was 64%, with an endemicity of 61% and 65% for amphibians and reptiles, respectively. The majority (69%) of the amphibian species occurred within the peatland area (peat swamp forests, grassland, and agricultural areas), while almost all (92%) of the reptile species were at least utilizing peatland edge/ecotone habitats. Around 43% of the amphibian species, mainly from the family Dicroglossidae, utilized terrestrial and aquatic microhabitats. For reptile species, a comparable portion of 46% utilized arboreal and terrestrial microhabitats. Lastly, it is crucial to implement conservation measures towards the unique ecology/biology of the herpetofauna species and the habitat dynamics in the peatland.

Although habitat selection has been studied in a variety of snake taxa, little is known about habitat selection in aquatic snake species. Additionally, due to their small size and secretive nature, juvenile snakes are seldom included in habitat selection studies. The Eastern cottonmouth Agkistrodon piscivorus is a semi‐aquatic pit viper known to use ambush, sit‐and‐wait foraging strategies. Ambush hunters are likely to select habitats that increase opportunity for successful prey capture while minimizing predation risk and maintaining appropriate thermal and hydric conditions. We characterized the foraging strategy and microhabitat use of cottonmouths at Ellenton Bay, an isolated Carolina bay freshwater wetland on the Savannah River Site in SC, USA. We measured habitat characteristics of 55 ambush sites used by 51 individual cottonmouths located during nighttime visual surveys, as well as 225 randomly selected sites within our search area. Cottonmouths exhibited an ontogenetic shift in foraging strategy with juveniles using predominately ambush foraging around the edge of the wetland while adults were most often encountered actively moving within the wetland. Principal components analysis revealed that juveniles selected foraging microhabitats that were different from random and consisted of mud substrate with sparse vegetation, whereas adults occupied a greater variety of microhabitats that did not differ from random. Concomitantly, free‐ranging cottonmouths exhibited ontogenetic shifts in diet: juveniles consumed mostly salamanders, while adults ate a greater variety of prey including other snakes and birds. Our results highlight the importance of understanding how ontogenetic changes in coloration, diet and predation risk influence foraging strategy and microhabitat selection in snakes.

Competition over spatial niche utilisation is one of most common competitive interactions between species in sympatry. Moreover, competitive interactions may involve age classes, and can fluctuate temporally. Consequently, evasive strategies that enable co‐existence are likely to be important in the evolution of species assemblages. Here we investigate a system of two co‐existing species of temperate geckos with similar ecologies (the house gecko, Hemidactylus turcicus and the wall gecko, Tarentola mauritanica ), providing an opportunity to study the effect of species interactions. Juveniles and adults of both species were investigated throughout their daily and annual cycle to explore the effect of inter‐ and intra‐specific interactions on microhabitat use. The two species showed differences in habitat use for both age classes in sympatry. In sympatry, T. mauritanica uses more open habitats and is more active. In contrast, H. turcicus is found in more closed habitats, closer to the ground and to vegetation cover. In allopatry, H. turcicus was observed in more open habitats, closer to the ground, and to vegetation cover, when compared to the population in sympatry with T. mauritanica . These differences in habitat usage were significant for both age classes. Moreover, there were differences, both in sympatry and in allopatry, between age classes that were dependent on season. In conclusion, the presence of a competitor induces a spatial shift in individuals of both age classes of H. turcicus . Observed plasticity in habitat utilisation in both age classes of H. turcicus is used to argue for the invasive potential of this species.

Cryptobenthic fishes occur in high densities on coral reefs, though due to their small size and cryptic nature they are often overlooked when quantifying reef biodiversity. This study examines their distribution on shallow reefs in SE Sulawesi, Indonesia, and assesses changes in habitat utilization when subject to reef degradation. Cryptic fishes were sampled from dominant microhabitat types in healthy and degraded reefs within the Wakatobi Marine National Park located in SE Sulawesi. High biodiversity of cryptobenthic fishes was found with 50 species representing 13 families. Traditional metrics (i.e. density, diversity) showed few differences between healthy and degraded reefs, though further investigations revealed differences occurred in community composition. Additional analyses of individual species demonstrated that reef degradation could have positive or negative effects on populations depending on type and strength of habitat associations. In summary, cryptobenthic fishes are altering their habitat use on degraded reefs, which will likely have repercussions on coral reef dynamics.

Microhabitat use and body morphology were compared among 15 warmwater stream fishes from the Alabama River (Alabama, U.S.A.) watershed. Morphological variation among separate populations of a species was detected in 14 of the 15 species, indicating that populations should be separated in analyses among species. Comparison of morphological variation between microhabitat generalist and specialist species suggested that all species may vary in morphology relative to their environment. Regression analysis showed that within two families, Cyprinidae and Percidae, morphology was related to specific microhabitat variables. In the Centrarchidae, morphology was not related to any microhabitat variables. Morphological differences among the species occurred along gradients that were similar to gradients of habitat utilization, indicating that within a family, species widely separated in microhabitat use were morphologically different and species using similar microhabitats were similar in morphology. Our results suggest that patterns of morphological variation correspond to properties of the available habitat for warmwater stream fish species.

Site d'etude: zone situee sous le barrage de Markles; problemes d'echantillonnage; nombre d'especes incluses dans l'analyse. Inclusion des jeunes d'un an dans cette analyse; interpretation et nouvelle analyse des modeles alternatifs

Species and size matter: An experimental study of microhabitat use under the influence of competitive interactions in intertidal gobiids

In spite of the potential richness in biodiversity, Manipur is still one of the least explored areas in northeastern India. In this work, we report on our finding of four pit viper species, namely, Trimeresurus mayaae, T. salazar, T. erythrurus, and Protobothrops jerdonii in Manipur during our herpetological surveys in 2022. We affirm the identity of these specimens based on the combination of standard morphological characters and mitochondrial cytochrome b gene. Our study not only reports four new records of pit vipers for the first time in Manipur, but also extends their respective known geographical ranges. This information calls for further dissemination especially to health care sector, as it is on venomous snakes that could be of medical importance as regards human snakebites.

The ecological relationships of three cricetine species–Peromyscus maniculatus, Peromyscus boylii, and Neotoma stephensi–and their utilization of habitat were revealed by species removals from unfenced plots and vegetation tailoring experiments. When N. stephensi, a woodland and shrubland species of woodrat, was removed from a manzanita—oak shrubland and pinyon—juniper woodland, P. boylii showed few significant changes in its use of the vegetational microhabitats on the grid or in the nature of its arboreal activity. However, when P. boylii, a woodland and shrubland mouse, was removed from a grid in juniper—oak shrubland and juniper grassland, both P. maniculatus, an inhabitant of open habitats such as grassland, and N. stephensi expanded their microhabitat utilization and changed their patterns of aboveground activity. Subsequent removal of both N. stephensi and P. boylii from this plot resulted in further expansion of arboreal activity by P. maniculatus. After crown removal of 0.75 ha of manzanita—oak shrubland, P. boylii, but not N. stephensi, avoided the newly opened area. Habitat selection, differential resource utilization, and interspecific competition all contribute to the coexistence of these three species in patchy habitats.

Microhabitat use studies of translocated species are crucial to assess their adaptation to the new environment. A total of 42 St Lucia whiptail lizards (Cnemidophorus vanzoi), an endemic to two islets (Maria Major, 10.2 ha and Maria Minor, 1.8 ha) off St Lucia in the Lesser Antilles, were translocated from Maria Major to Praslin Island (1.1 ha) in 1995. Three years after the release, we studied the abundance, density and distribution of the translocated lizard population in the prevailing five habitat types on the island. Habitats varied from more exposed open grasslands to tall, continuously canopied woodlands. Although lizards were distributed throughout the island, some habitats were used more than predicted with respect to availability. Habitat utilization showed a seasonal shift in distribution. Line transect sampling estimated a population of 145 ± 23 lizards on Praslin Island. There were significant seasonal differences in estimated lizard abundance indicating a change in activity during the dry season. Lizard density was significantly correlated with general habitat characteristics, rather than with any specific microhabitat variable measured. Factors affecting distribution (thermo‐regulation, food resources and competitive exclusion) are discussed and it is suggested that habitat use during the dry season may be best explained by thermal constraint. These results will help managers choose future translocation sites.

Stochasticity in Stream Fish Communities: An Alternative Interpretation

We conducted a radio tracking study to assess movement patterns and microhabitat use of lotic turtles during their nesting and hibernation seasons. During the nesting season, female turtles moved from the sandbank along the river to the outer-embankment and/or inner-embankment that includes rice fields. The maximum movement distance was over 2.5 km. Turtles frequently utilized terrestrial microhabitats for basking but also for other activities such as feeding and resting. Calm, deep aquatic sites near banks were used for hibernation. These results indicate that large areas that include different microhabitat type (both aquatic and terrestrial) are essential for freshwater turtles inhabiting river environments.

The species assemblages of cichlids in the three largest African Great Lakes are among the richest concentrations of vertebrate species on earth. The faunas are broadly similar in terms of trophic diversity, species richness, rates of endemism, and taxonomic composition, yet they are historically independent of each other. Hence, they offer a true and unique evolutionary experiment to test hypotheses concerning the mutual dependencies of ecology and brain morphology. We examined the brains of 189 species of cichlids from the three large lakes: Victoria, Tanganyika, and Malawi. A first paper demonstrated that patterns of evolutionary change in cichlid brain morphology are similar across taxonomic boundaries as well as across the three lakes [van Staaden et al., 1995 ZACS 98: 165-178]. Here we report a close relationship between the relative sizes of various brain structures and variables related to the utilization of habitat and prey. Causality is difficult to assign in this context, nonetheless, prey size and agility, turbidity levels, depth, and substrate complexity are all highly predictive of variation in brain structure. Areas associated with primary sensory functions such as vision and taste relate significantly to differences in feeding habits. Turbidity and depth are closely associated with differences in eye size, and large eyes are associated with species that pick plankton from the water column. Piscivorous taxa and others that utilize motile prey are characterized by a well developed optic tectum and a large cerebellum compared to species that prey on molluscs or plants. Structures relating to taste are well developed in species feeding on benthos over muddy or sandy substrates. The data militated against the existence of compensatory changes in brain structure. Thus enhanced development of a particular function is generally not accompanied by a parallel reduction of structures related to other modalities. Although genetic and environmental influences during ontogeny of the brain cannot be isolated, this study provides a rich source of hypotheses concerning the way the nervous system functions under various environmental conditions and how it has responded to natural selection.

Despite their high diversity and importance as top predators in many ecosystems, the ecology of many snakes remains poorly understood. This situation is especially true at low latitudes, as few attempts have been made to quantify patterns of space usage by tropical snake species. Here, we describe macro- and microhabitat use by the abundant pit viper Bothrops asper in the lowlands of Costa Rica. Specifically, we used radiotelemetry to monitor nine female and four male adult snakes at La Selva Biological Station between 2004 and 2006. We determined macrohabitat usage and availability on the basis of the movements of individual snakes and analyzed selection using compositional analysis. Microhabitat was quantified by a series of structural characteristics, and groups of locations were compared using multivariate ANOVA and discriminant function analysis. In our study, B. asper demonstrated a positive selection for swamp habitat and avoidance of human-disturbed areas by both male and female snakes. Microhabitat usage did not differ between males and females, but did differ for all individuals between daytime observations, when snakes were typically inactive, and nocturnal observations, when snakes moved to more exposed areas and foraged using ambush tactics. Microhabitat characteristics were significantly nonrandom at both times, suggesting that B. asper actively select particular sites for both diurnal retreat and nocturnal foraging sites. These data emphasize that the contrasting ways in which animals may utilize resources at separate times or for different activities should be considered in studies of overall habitat selection.