Herpetofaunal Community Research Articles

Can a large metropolis sustain complex herpetofauna communities? An analysis of the suitability of green space fragments in Rome

AbstractUrban areas are primary causes of species' range fragmentation and reduction. However, relatively few studies have attempted to describe the habitat variables influencing the diversity and conservation of amphibians and reptiles, particularly in Mediterranean Europe and in large metropolitan areas. We explored this broad conservation ecology problem by studying the richness and diversity patterns in relation to a suite of six independent habitat variables in Rome, one of the most ancient cities of the world. We considered all the green remnant areas (n=62) of Rome, ranging 1 to >1000 ha in size, which are interspersed within a sea of urbanized matrix. A total of 10 amphibian and 15 reptile species were studied. Their presence/absence patterns were assessed and the effects of the various habitat variables on each species were predicted by a logistic regression model. A total of 1261 presence records (404 amphibians and 857 reptiles) were analysed. Fragment size and wood size within each fragment did correlate significantly with the species richness of both amphibians and reptiles, and there was a clear threshold effect after 50 ha of wooded surface. The presence of water bodies positively affected the species distribution. One amphibian and three reptiles inhabited exclusively fragments >50 ha. The distance from the centre did not affect fragment species richness. The presence of most species of both amphibians and reptiles was positively influenced by the irregular versus circular shape of the wooded area. The legal protection of a given area did not influence the observed patterns but the total number of sheltered species. Overall, our study suggests that, in order to maintain the current diversity and population viability, it is necessary, in addition to water bodies' maintenance, to (1) preserve the wooded landscapes over 50 ha; (2) promote irregularly shaped increases in the wood surface; (3) maintain ecotonal boundaries.

Measuring species diversity to determine land-use effects on reptile and amphibian assemblages

AbstractPopulations of herpetofauna are declining globally primarily due to land-use practices (e.g., silviculture or conversion to agriculture) and declines require monitoring of all herpetofauna communities. Therefore, forest management plans for Bull Neck Swamp, a pocosin wetland in North Carolina, USA, initiated an inventory of the herpetofauna community. Our objectives were to: (1) derive diversity measures for four designated habitat preserves (i.e., Atlantic whitecedar [Chamaecyparis thyoides], Pond pine [Pinus serotina], Non-riverine Swamp, and Shoreline/Islands) and a Forest manageable area, (2) determine if there were benefits to habitat preserves for the herpetofauna community, and (3) provide recommendations for future monitoring. We employed 11 different sampling techniques across the four habitat preserves and Forest manageable area. Species richness estimates and similarity indices were derived using EstimateS 8.0. For post hoc comparisons, we derived species distributions with the Nestedness Temperature Calculator Program. Observed species richness ranged from 7 to 32 species (S = 13 to 44) and abundances ranged from 99 to 873 individuals. Similarity indices suggested species compositions were similar among habitats. Further, nestedness temperature (T = 12.6°C) indicated an even species distribution among assemblages. Comparable similarity indices among habitats, an even species distribution, and habitat continuity suggested management practices would have little impact on the herpetofauna community. Nevertheless, future management practices should be carefully considered and planned to mitigate effects to individual species. We recommend studies employ species richness, relative abundance, species composition, and distribution as conservation tools when inventorying or monitoring herpetofauna communities.

A rapid assessment of herpetofaunal diversity in variously altered habitats on Dominica

In June 2008, we conducted a survey of Dominican herpetofaunal communities in habitats variously disturbed by human activity. Our rapid assessment found the highest abundance and species richness in moderately to substantially modified areas. We found relatively few species and low numbers of individuals in relatively natural high-elevation sites, dramatically altered urban areas, and active agricultural fields. In habitats subjected to intermediate levels of disturbance, such as a residential area and an inactive agricultural site invaded by dense exotic vegetation, complex physical habitat structure appeared to support the greatest herpetofaunal diversity. These results suggest that conservation efforts in the West Indies need not be restricted to pristine habitats, but also might include protection of slightly to moderately disturbed areas that may sustain greater biodiversity.

The Amphibians and Reptiles of the Estación Biológica Jatun Sacha in the Lowland Rainforest of Amazonian Ecuador: A 20-Year Record

The amphibian and reptile fauna within a small area in a lowland rainforest fragment reserve in Amazonian Ecuador was intensively surveyed over an initial 2- year period via removal sampling (1986-88), coinciding with the construction of a road through the area and a subsequent surge of increased forest conversion and fragmentation in surrounding areas. A time-constrained transect sampling technique was employed to facilitate later, post-fragmentation visual-encounter monitoring to gather long-term data on species richness and composition (on a chronologically coarse scale). Between 1998 and 2005, an approximately equivalent quantity of sampling effort was accumulated in the same small area to compare with data from 1986-88, in an attempt to evaluate the efficacy of this reserve in conserving the herpetofaunal community documented more than 10 years earlier. Based on a total of 6,722 individual records obtained over 1,117 effort-hours of sampling divided into two primary and five secondary sampling periods, herpetofaunal species richness was among the highest yet reported from a single locality in Amazonia, with 84 amphibian and 82 reptile species recorded from 1986 through 2007. A complete species list is provided, with commentary on noteworthy records. Of 73 amphibian and 46 reptile species recorded in 1986-88 sampling, 68 amphibians (93%) and 40 reptiles (87%) were recorded again in sampling from 1998 through 2007; 11 amphibian and 33 reptile species not recorded in 1986-88 were added from 1998 to 2007. Pairwise comparisons of species composition among all sampling periods using a similarity index revealed a . 50% similarity for both taxonomic groups across all periods; similarity of the two primary periods (1986-88 vs. 1998-2005) was 0.90 for amphibians and 0.70 for reptiles. The present study provides another single-site reference point for the mega-diverse herpetofauna of the upper Amazon basin, but is distinct in offering long-term data on species persistence; results from the 20-year span of sampling suggest that this small reserve has, since 1986, successfully conserved this fauna. These results concur with previous long-term studies from the central Amazon basin in suggesting that relatively small reserves and other forest remnants with sufficient habitat diversity may substantially contribute to the continued survival of species-rich Amazon rainforest herpetofaunal communities amidst widespread regional deforestation.

Herpetofauna of an Atlantic rainforest area (Morro São João) in Rio de Janeiro State, Brazil

We studied the herpetofaunal community from the Atlantic forest of Morro São João, in Rio de Janeiro State, Brazil, and present data on species composition, richness, relative abundance and densities. We combined three sampling methods: plot sampling, visual encounter surveys and pit-fall traps. We recorded sixteen species of amphibians and nine of reptiles. The estimated densities (based on results of plot sampling) were 4.5 ind/100 m2 for amphibians and 0.8 ind/100 m2 for lizards, and the overall density (amphibians and lizards) was 5.3 ind/100 m2. For amphibians, Eleutherodactylus and Scinax were the most speciose genera with three species each, and Eleutherodactylus binotatus was the most abundant species (mean density of 3.0 frogs/100 m2). The reptile community of Morro São João was dominated by species of the families Gekkonidae and Gymnophtalmidae (Lacertilia) and Colubridae (Serpentes). The gymnophtalmid lizard Leposoma scincoides was the most abundant reptile species (mean density of 0.3 ind/100 m2). We compare densities obtained in our study data with those of other studied rainforest sites in various tropical regions of the world.

Getting the Drift: Examining the Effects of Timing, Trap Type and Taxon on Herpetofaunal Drift Fence Surveys

The evaluation of appropriate sampling methodologies is critical for accurately determining the distribution and status of herpetofaunal populations. We report the results of a year-long drift fence study, using multiple trap types (large pitfall traps, small pitfall traps and funnel traps), of a species-rich herpetofaunal community (59 species) surrounding an isolated wetland in the southeastern United States. Specifically, we determined the effects that timing, trap type and taxon had on capture rates of herpetofauna. We found that funnel traps captured the greatest number of herpetofaunal species, but a combination of funnel traps and large pitfall traps yielded the greatest number of individual captures due to complementary biases in capture efficiencies among herpetofaunal taxa. With little exception, small pitfall traps were relatively ineffective for sampling herpetofauna. We also found that the timing of drift fence monitoring affected herpetofaunal species accumulation rates but that seasonal effects were taxon-specific. Our study affirms that drift fences are exceptional tools for inventorying and monitoring diverse species and large numbers of herpetofauna and also demonstrates the important effects that season and taxon can have on capture rates. Therefore, we recommend a priori delineation of project goals and the use of multiple trap types with careful attention to the timing of drift fence monitoring to maximize sampling efficiency and minimize biases associated with data collection.

Changes in a Northwestern Florida Gulf Coast Herpetofaunal Community Over a 28-y Period

ABSTRACT Population declines of amphibians and reptiles throughout the world have led to the initiation of projects to monitor their status and trends. Historical collections give an indication of which species occurred in an area at one time, although the ambiguity surrounding locations and environmental conditions associated with collection decreases the value of this information source. Resampling using the same general protocols can give valuable insights to changes in community structure. However, this is only feasible when sampling methodology and exact site locations are known. From 2002–2005 we resampled 12 sites in St. Marks National Wildlife Refuge in Florida's panhandle, an area in which intensive herpetological surveys were conducted in 1977–1979. We documented a general decrease in species richness among the diversely managed sites, changes in dominant species and diversity and an increasing trend toward homogeneity of the herpetofaunal community among habitats. Changes were attributed to fou...

Herpetofaunal communities of the leeward slopes and coasts of St. Vincent: A comparison of sites variously altered by human activity

Like other Lesser Antillean islands, human-modified habitats are prevalent on much of St. Vincent, especially in coastal regions. Eighteen terrestrial species of reptiles and amphibians are known to occur on the island. Some species demonstrate considerable versatility, and are found in both altered and relatively natural habitats. Others, however, are restricted to one extreme or the other. To better understand the composition of herpetofaunal communities, we surveyed seven sites on the leeward side of the island, chosen to represent different degrees of human alteration. We found the highest diversity index in an urban area, where introduced species prevailed. Endemic species were more abundant in more natural sites. Three species, Eleutherodactylus johnstonei, Anolis griseus, and A. trinitatis, were at all sites.

EFFECTS OF RANGELAND MANAGEMENT ON COMMUNITY DYNAMICS OF THE HERPETOFAUNA OF THE TALLGRASS PRAIRIE

The Flint Hills of Kansas and Oklahoma are the largest remaining tracts of tallgrass prairie in North America. This area has undergone major changes in land management practices in the past 30 years. Traditional season-long cattle stocking with variable burn schedules has diversified to include intensive-early cattle stocking accompanied by annual burning. To understand how different land management practices affect the herpetofauna of a tallgrass prairie, we used mark-recapture statistics to analyze herpetofaunal community dynamics. We analyzed survey data collected over a 15-year time span (1989-2003) from a rangeland site in Cowley County, KS, USA. A modified Jolly-Seber open population model, POPAN-5, was used to estimate four community parameters: probability of species loss (w9), probability of detection (p), probability of entry (Pent), and species richness (N). The top models included burn status as a covariate for species loss rate, while cattle stocking received moderate support as a covariate. Rates of species loss were higher during burn years (w 95 0.04, 95% CI: 0.02 to 0.08) than nonburn years (w 95 0.00, 95% CI: 0.00 to 0.01). Analysis of the impacts of different management practices was difficult due to confounding effects of changes in both burning and grazing. Declines in species richness tended to be steepest during a period of season-long stocking, but results were not statistically significant. Though our limited data set does not allow us to draw strong conclusions on the effects of land management on herpetofaunal populations, the mark- recapture models illustrated in our study should prove to be a valuable tool in future analyses of similar data. THE TALLGRASS prairie has been reduced to less than five percent of its pre-European settlement extent, making it the most heavily impacted ecosystem in North America (Sam- son and Knopf, 1994). The largest contiguous section of remaining tallgrass prairie occurs in the Flint Hills of northern Oklahoma and Kansas (Knapp and Seastedt, 1998). Much of this region is unsuitable for row-crop agricul- ture because shallow soils are associated with limestone bedrock. However, the Flint Hills provide extensive rangeland for cattle. Much of the rangeland experienced a marked change in land management in the early 1980s. Traditionally, ranchers practiced sea- son-long cattle stocking, which allowed a lim- ited number of cattle to graze year-round, accompanied by rotation of burned and unburned areas every 2-3 years. Under in- tensive-early stocking, cattle stocking rates were roughly double that of the previous practice for only 90-120 days in the growing season with annual spring burns, which in-

Preliminary biodiversity assessment (herpetofauna and mammals) of a coastal wetland in the Volta Region, Ghana

Herpetofaunal and mammal species were surveyed in four contrasting habitats (grassland/thicket, agricultural/urban, freshwater ponds/ditches, and brackish lagoon) in a coastal wetland and lagoon (Keta) during June-July 1997 and May-June 1998, using direct observation, live-trapping, refuge searches, transect walks, and interviews. The survey recorded a total of 13 species of herpetofauna and seven species of mammal species. The most diverse herpetofaunal community was in grassland, with 11 herpetofaunal species, while the least diverse habitat was brackish lagoon, with three herpetofaunal species. An interview of the local inhabitants showed the presence of bushbucks (Tragelaphus scriptus) and grasscutters (Thryonomys swinderianus), which are common bushmeat species in Ghana. It is recommended that herpetofaunal conservation efforts in the area should focus on protection and monitoring of grassland/ thicket habitats and freshwater ponds, since mammalian species diversity of the area is already very low for a variety of reasons. Ghana Journal of Science Vol. 45, 2005: 19-26

An Evaluation of the Contribution of Cultivated Allspice (Pimenta Dioca) to Vertebrate Biodiversity Conservation in Nicaragua

Tropical deforestation has emerged as one of the most important conservation challenges of our time, both because of the high species diversity and rates of endemism of tropical forests, and because of the rapid rate at which this process is proceeding. Recent studies indicate that areas of low-intensity agroforestry have similar levels of vertebrate diversity as some primary habitats, leading some researchers and conservationists to conclude that this type of commodity production could contribute to the conservation of biodiversity. We compared the composition of bird, mammal and herpetofaunal communities in primary forest, secondary forest, and pasture—and within the allspice productive systems that have replaced pasture. We found that mammal species richness was higher in primary forest than all other habitats; however for resident and migrant birds, amphibians and reptiles, species richness was similar between primary forest and the other habitats. Despite similarities in overall numbers of species, there were numerous species that were encountered only in primary habitats. We conclude that the cultivation of allspice in a mixed productive system can offset some of the losses to biodiversity; however it should be complemented by the establishment and maintenance of protected areas to accommodate populations of primary forest specialists that are unable to persist in altered habitats.

Herpetofaunal Diversity of Alligator River National Wildlife Refuge, North Carolina

In the past century, habitat alteration and fragmentation have increased dramatically, which increases the need for improving our understanding of how species and biological communities react to these modifications. A national strategy on biological diversity has focused attention on how these habitat modifications affect species, especially herpetofauna (i.e., changes in species richness, community evenness and similarity, and dominant/rare species). As part of this strategy, we surveyed Alligator River National Wildlife Refuge, a coastal, mixed second-growth forested swamp (MFS) and pocosin wetland (PW), in North Carolina for amphibians and reptiles from September 2000 to August 2001. We randomly selected three sites (3 x 3 km) in two major habitat types (MFS, PW) and completed random surveys and trapping using transects, quadrats, nighttime aural road surveys, drift fences, canal transects, coverboards, incidental captures, and evening road surveys. We also col- lected herpetofauna opportunistically throughout the refuge to establish an updated species list. For analysis, we used Shannon-Weiner species diversity (H'), evenness (J'), species richness and species detectability (COMDYN4), and community percent similarity index to determine herpetofaunal community differences. We estimated 39 species in MFS and 32 species in PW (P < 0.10). Species detectability was similar between habitats (0.84 to 0.86). More reptilian species (+ 31%) inhabited MFS than PW, but estimated amphibian species richness was identical (17 spp.). H' was higher (P < 0.0001) for PW (2.6680) than for MFS (2.1535) because of lower J' in the latter (0.6214 vs. 0.8010). Dominance of three Rana species caused lower J' and H' in MFS. Similarity between the communities was 56.6%; we estimated 22-24 species in common for each habitat (95% CI = 18 to 31 spp.). We verified 49 of the 52 herpetofaunal species on the refuge that were known to exist in the area. Restoration of natural water flows may affect herpetofaunal diversity, which may be monitored during a restoration project. Currently, the refuge retains historical levels of herpetofaunal diversity for the region.

Efficiency of Adaptive Cluster and Random Sampling in Detecting Terrestrial Herpetofauna in a Tropical Rainforest

We sampled forest floor herpetofaunal communities in a monsoonal rainforest in South India for three consecutive years to evaluate the use of cluster sampling in estimating species composition and density. Our initial experimental design consisted of comprehensive random searches of multiple 25m2 quadrats (SRS) for animals. After our initial season we found that most quadrats had zero animals detected and, when encountered, animals were spatially aggregated. To increase sampling efficiency and derive more precise density estimates, we shifted to adaptive cluster sampling (ACS). We compared the relative sampling efficiencies of ACS to SRS and the ability of the 2 methods to detect rare species. Adaptive cluster sampling failed to yield the more precise density estimates as predicted by statistical theory. However, ACS yielded more individual and rare species detections. Our results suggest the ACS assumptions should be carefully evaluated prior to use because it may not be appropriate for all rare, spatially aggregated populations.

Variação da composição da comunidade de artrópodes das formações florestadas do extremo sul da Bahia: disponibilidade de recursos alimentares para lagartos e anuros de serrapilheira

Suitable estimates of the composition of communities are important elements for the solution of ecological problems. Distinct empirical methodologies for its evaluation, however, may estimate differently the parameters of interest. Arthropods are key elements to ecosystems and represent a diverse and extremely numerous group in terrestrial environments. They represet the main source of food resources for the herpetofauna communities, thus, evaluating its composition and distribution in a complex landscape, as it is the case studied, is key to understand the ecological processes in the area. This work intended to evaluate three main aspects out of the proposed model: (1) to measure the abundance estimates of the leaflitter arthropods communities in a forested landscape based on pitfall trapping and on analysis of arthropods found in stomach contents of the herpetological fauna. (2) To detect the main variation in the composition of the forest leaflitter arthropod community in a fragmented landscape in the extreme south of the state of Bahia and to associate it with variations in environmental factors. (3) And to study the use and eletivity of food resource by the leaflitter herpetofauna in an Atlantic forest remnant (6,069 ha). The study was conducted at the RPPN Estacao Veracruz, a private reserve in the extreme south of Bahia, Brazil. We compared the diets of frogs and lizards captured in 432 drift fence pitfall traps, distributed in four areas between January 2003 and February 2004. We analyzed three landcape components: reference forest (M); forest remnant (R); and eucalypt monoculture (E). Captures based on an effort of 17,280 pitfall traps in 40 days sampling expedition and on the stomach contents present in 523 frogs and 206 leaflitter lizards captured in the same way. There has been collected animals from 12 families, in a total of 21 frogs and lizard species from the following families: Teiidae (4), Polychrotidae (3), Gekkonidae (1), Tropiduridae

Influence of climate, elevation, and land use in regional herpetofaunal distribution in Tochigi Prefecture, Japan

Understanding the relationship between the distribution of organisms and their environment is important for regional conservation planning. While most herpetofaunal community studies address environmental influence on species richness, few studies describe environmental influence on species composition at geographic scales. Field surveys of herpetofauna were conducted during 1994-2000 in Tochigi Prefecture, which covers ca. 6400 km_ of mainland Japan and includes a wide range of elevation, annual mean temperature, and human population densities. We evaluated whether (i) regional herpetofauna are distributed along a gradient of climate and elevation, as well as land cover and land use, and (ii) 'climate/elevation' and 'landcover' variables differ in their relative contribution. Ordination indicated a strong geographic gradient in species composition that was correlated with climate, elevation, land cover and land use. Reptiles were strongly influenced by land cover and land use (residential, agricultural, ...

Herpetofaunal Richness and Community Structure of Offshore Islands of Sulawesi, Indonesia1

ABSTRACTWe examined the distribution and broad habitat associations of the herpetofauna on three offshore islands of southeast Sulawesi, Indonesia. A total of 74 amphibian and reptile taxa were recorded, comprising 13 frogs, 29 lizards, 29 snakes, 1 freshwater turtle, and 1 crocodile. Of the total taxa, 38 percent were endemic to Sulawesi, 13 were new undescribed taxa. Range extensions were also recorded for one taxon previously not known from Sulawesi. Herpetofauna of these islands is largely derived from that of mainland Sulawesi, and as for Sulawesi generally, is depauperate compared with herpetofaunal assemblages in Borneo, Java, and Thailand. Taxon richness was much higher in minimally disturbed forest and forest habitats with only moderate disturbance levels than in highly modified or disturbed habitats, such as secondary forests, plantations, and villages. Disturbed habitats were characterized by widespread, habitat generalists and human commensals. Forests were characterized by endemic and habitat‐specialist taxa. Little discrimination of taxon composition or endemism was found between minimally and moderately disturbed forest habitats. These results reaffirm the need for more general biological survey and research in this region. Taxa most likely to be displaced by human impacts tend to be endemic taxa, for which there exists little or no ecological information. The similarity in the herpetofaunal community structure between habitats with minimal and moderate disturbance levels has important implications for our understanding of ecological resilience in tropical herpetofaunal communities.

Analysis of a herpetofaunal community from an altered marshy area in Sicily; with special remarks on habitat use (niche breadth and overlap), relative abundance of lizards and snakes, and the correlation between predator abundance and tail loss in lizards

A field survey was conducted in a highly degraded barren environment in Sicily in order to investigate herpetofaunal community composition and structure, habitat use (niche breadth and overlap) and relative abundance of a snake predator and two species of lizard prey. The site was chosen because it has a simple community structure and thus there is potentially less ecological complexity to cloud any patterns observed. We found an unexpectedly high overlap in habitat use between the two closely related lizards that might be explained either by a high competition for space or through predator-mediated co-existence i.e. the prevention of the competitive exclusion of one lizard over the other. We also found a strong positive correlation between predator density and tail damage in lizards and we suggest that tail damage is a direct consequence of snake activity (because no other natural predators occur in the area).

Biotic diversity of Natchez Trace State Forest, western Tennessee.

We carried out a multiple-scale assessment of biotic resources within Natchez Trace State Forest (NTSF) in western Tennessee, focusing on the relation between biotic communities and seven previously developed ecological land types (ELT, based on topography and soils). We wanted to test the functional ability of ELTs for biodiversity stewardship. Woody and herbaceous flora as well as herpetofauna and avifauna communities had substantial differences between upland and lowland forests. However, none of the faunal communities distinguished among upland ELTs. In addition, herbaceous taxa also failed to distinguish upland ELTs. The results suggest the present use of ELTs at NTSF will not be a helpful guide to land stewardship focusing on biodiversity. The disturbance history of the Forest and the mobility of animals are given as potential explanations for a poor relationship between abiotic ELTs and the resident biota.

Continental Physiography, Climate, and the Global Distribution of Human Population

Continental Physiography, Climate, and the Global Distribution of Human Population

Monitoring herpetofauna in a managed forest landscape: effects of habitat types and census techniques

We surveyed the herpetofaunal (amphibian and reptile) communities inhabiting five types of habitat on a managed landscape. We conducted monthly surveys during 1997 in four replicate plots of each habitat type using several different methods of collection. Communities of the two wetland habitats (bottomland wetlands and isolated upland wetlands) were clearly dissimilar from the three terrestrial communities (recent clearcut, pine plantation, and mixed pine–hardwood forest). Among the three terrestrial habitats, the total herpetofaunal communities were dissimilar ( P<0.10), although neither faunal constituent group alone (amphibians and squamate reptiles) varied significantly with regard to habitat. Three survey techniques used in the terrestrial habitats were not equally effective in that they resulted in the collection of different subsets of the total herpetofauna. The drift fence technique revealed the presence of more species and individuals in every habitat and was the only one to detect species dissimilarity among habitats. Nonetheless, coverboards contributed to measures of abundance and revealed species not detected by other techniques. We suggest that a combination of census techniques be used when surveying and monitoring herpetofaunal communities in order to maximize the detection of species.