Reptile Species Richness Research Articles

Patterns of diversity along a habitat size gradient in a biodiversity hotspot

AbstractHabitat destruction and loss are the gravest threats to wildlife worldwide. We examined the correlation between habitat patch size and species richness and abundance of mammals and reptiles in a biodiversity hotspot in California. Within nine forest fragments standardized for age, topography, climate, and vegetation cover, we tested the effects of patch size and isolation on biodiversity. To measure species richness and abundance, we used wildlife cameras for meso‐and‐large vertebrates, mark‐and‐recapture analyses for small mammals, mark‐and‐resight analysis for reptiles, and standard dragging techniques for tick collections because they are frequent ectoparasites on vertebrates in oak woodland habitats. Our results show that meso‐and‐large vertebrate richness and abundance increase with patch area as does tick density. Surprisingly, small mammal species richness and abundance peak in intermediate‐sized fragments. Resource limitation and competition at the smallest habitats and predation at the largest patches may be responsible for this pattern. Further, there is a significant decrease in invasive species richness with habitat patch size. We found that habitat destruction and fragmentation are acting upon species and communities in context‐dependent ways that is critical to conservation planning, land use design, and ecosystem function.

Herpetofaunal species presence in buffel grass (Cenchrus ciliaris) versus native vegetation‐dominated habitats at Uluṟu‐Kata Tjuṯa National Park

AbstractBuffel grass (Cenchrus ciliaris) has been established in Uluṟu‐Kata Tjuta National Park since 1968. To date, the influence of buffel grass on the Park's flora and fauna has been largely unassessed. The objectives of this study were to determine if buffel grass dominates vegetation communities at the base of Uluṟu and if buffel grass habitats are associated with lower reptile and amphibian species richness than endemic vegetation communities. We used vegetation transects to measure the amount of buffel grass and genera of endemic vegetation at 26 sampling locations around the base of Uluṟu. The vegetation survey data were paired with pitfall trap data from reptile and amphibian captures at the same sampling locations. Indicator species analysis and non‐metric multidimensional scaling were used to analyse the vegetation and herpetofaunal community data. Our analyses determined five distinct vegetation communities around Uluṟu. At the base of Uluṟu, buffel grass dominated half of sampled areas and the rest of the inselberg's base was dominated by Themeda grasses. Buffel grass habitats had significantly higher herpetofaunal species richness than the Themeda habitats that dominated other areas at Uluṟu's base. Herpetofauna species richness in buffel grass‐dominated habitats was also significantly higher than all vegetation communities except for Triodia‐dominated habitats. These observations do not directly indicate that buffel grass presence promotes higher species richness of reptiles and amphibians since the observed patterns may be driven by factors such as proximity to breeding sites and abiotic variables not directly related to the grass itself.

Reptile surveys reveal high species richness in areas recovering from mining activity in the Brazilian Cerrado

AbstractOur study determines the reptile species richness, composition, and habitat use in three areas recovering from mining activity in addition to the adjacent pristine and anthropized areas of a priority region for biodiversity conservation of the Brazilian Cerrado. We also compared our data with published surveys on the Cerrado domain in order to identify areas with unique species composition and/or areas where the reptile composition is more homogeneous. The survey was conducted in the municipality of Niquelândia, northern Goiás state, central Brazil, and involved reptile samplings from different physiognomies and water bodies. We found 47 species, including one crocodilian, one chelonian, two amphisbaenians, 17 lizards, and 26 snakes. The list includes 37 species with large geographic distribution, occurring in other morphoclimatic domains, as well as 10 species which are endemic to the Cerrado. Some species recorded for the region are listed in the Appendices I and II of the CITES. Many reptile species were frequently associated with anthropogenic habitats, while others seem to depend on remnants of pristine habitats. Low similarity was found among the 32 sites considered across the Cerrado domain. Ten sites located in Cerrado regions in contact with the adjacent domains have unique reptile composition, whereas most sites largely located in the central area of the domain have reptile communities which are more homogeneous among them. It is important to conduct long-term studies to have patterns of reptile species composition recognized as well as population decline and/or local extinctions and effective reptile conservation actions, with focus on these sites considering their unique species.

Diversity, biogeography and the global flows of alien amphibians and reptiles

AbstractAimWe introduce a high‐quality global database of established alien amphibians and reptiles. We use this data set to analyse: (1) the global distribution; (2) the temporal dynamics; (3) the flows between native and alien ranges; and (4) the key drivers of established alien amphibians and reptiles.LocationWorldwide.MethodsWe collected geographical records of established amphibians and reptiles from a thorough search across a wide number of sources. We supplemented these data with year of first record, when available. We used descriptive statistics and data visualization techniques to analyse taxonomic, spatial and temporal patterns in establishment records and the global flows of alien species. We used generalized linear mixed models to relate spatial variation in the number of established species richness with variables describing geographical, environmental and human factors.ResultsOur database covers 86% of the terrestrial area of the world. We identified 78 alien amphibian and 198 alien reptile species established in at least one of our 359 study regions. These figures represent about 1.0% of the extant global amphibian and 1.9% of the extant global reptile species richness. The flows of amphibians were dominated by exchanges between and within North and South America, and within Europe (59% of all links). For reptiles, the network of global flows of established alien species was much more diverse, with every continental region being both a donor and a recipient of similar importance. The number of established alien amphibians and reptiles has grown slowly until 1950 and strongly increased thereafter. Our generalized linear mixed models revealed that insularity, climatic conditions, and socio‐economic development significantly influenced the distributional patterns for both groups.Main conclusionsWe conclude that biological invasions by alien amphibians and reptiles are a rapidly accelerating phenomenon, particularly on islands with heterogeneous climates of economically highly developed countries.

Passive recovery of small vertebrates following livestock removal in the Australian rangelands

AbstractIn arid environments, grazing by exotic herbivores, including domestic livestock, can greatly influence native, small vertebrate assemblages. Whether the removal of livestock facilitates passive recovery of these assemblages depends on habitat condition and the species present. We explore changes in small mammal and reptile species richness, abundance, and composition in a degraded chenopod shrubland dominated by Acacia victoriae ssp. and open Acacia aneura (mulga) woodland destocked in 1976 and 1984, respectively. Data were obtained between 1997 and 2007, from two grazed and two ungrazed sites in each community. Species richness increased at a faster rate in ungrazed open A. aneura woodland, but did not differ significantly between ungrazed and grazed degraded chenopod shrubland. Subsequent analyses at a finer‐scale detected disparate responses in richness and abundance for microhabitat. At this scale, a greater number of species‐specific responses were also detected, including increased abundance of generalist species and decreased abundance of species requiring low cover. These results reiterate the potential for species‐specific responses to livestock that are more apparent in particular microhabitats. Furthermore, this investigation provides evidence for the gradual passive recovery of small mammal and reptile assemblages in both communities, which is facilitated by the removal of livestock in open A. aneura woodland in fair condition, but not degraded chenopod shrubland in poor condition.

What do Data from Fieldwork and Scientific Collections Tell us about Species Richness and Composition of Amphibians and Reptiles?

Combining different sampling methods is essential to determine species richness. Recently, herpetological surveys have been conducted in poorly sampled regions in Brazil using data from scientific collections as complementary information for richness estimated from fieldwork. However, few studies have evaluated discrepancies between estimation of species richness obtained from fieldwork and scientific collections. Here, we demonstrate quantitatively how data available in scientific collections can be important complementary sources for assessing amphibian and reptile species richness. We used rarefaction and PERMANOVA to compare species richness and composition, respectively, of amphibians and reptiles from fieldwork carried out in southeastern Brazil with data from four of the most representative herpetological collections in the São Paulo state, southeastern Brazil. Our results showed no difference between amphibian species richness recorded in the field and scientific collections. In contrast, reptile species richness recorded in scientific collections was 2.5 times higher than in the fieldwork. Furthermore, pooling data from fieldwork and scientific collections increased amphibian and reptile species by 25% and 75%, respectively. Species composition of both amphibians and reptiles were significantly different between field survey and scientific collections. Thus, future inventories, ecological, and taxonomic researches may considerably benefit from information available in scientific collections.

Remnant vegetation, plantings and fences are beneficial for reptiles in agricultural landscapes

Summary Managing agricultural landscapes for biodiversity conservation is increasingly difficult as land use is modified or intensified for production. Finding ways to mitigate the negative effects of agriculture on biodiversity is therefore critical. We asked the question: How do remnant patches, paddock types and grazing regimes influence reptile assemblages in a grazing landscape? At 12 sites, we surveyed reptiles and environmental covariates in remnant woodland patches and in four paddock types: (i) grazed pasture, (ii) linear plantings, (iii) coarse woody debris (CWD) added to grazed pasture and (iv) fences between grazed pasture. Each site was either continuously or rotationally grazed. Remnant vegetation and other vegetation attributes such as tree cover and leaf litter greatly influenced reptiles. We recorded higher reptile abundance and species richness in areas with more tree cover and leaf litter. For rare species (captured in ≤4 sites <70 captures), there were 5·7 more animals and 2·6 more species in sites with 50% woody cover within 3 km compared to 5% woody cover. The abundance and richness of rare species, and one common species differed between paddock types and were higher in linear plantings and fence transects compared to CWD and pasture transects. Synthesis and applications. Grazed paddocks, particularly those with key features such as fences and plantings can provide habitat for reptiles. This suggests that discrete differentiation between patch and matrix does not apply for reptiles in these systems. Management to promote reptile conservation in agricultural landscapes should involve protecting existing remnant vegetation, regardless of amount; and promote key habitat features of trees, leaf litter and shrubs. Establishing plantings and fences is important as they support high numbers of less common reptiles and may facilitate reptiles to move through and use greater amounts of the landscape.

Non‐target impacts of weed control on birds, mammals, and reptiles

AbstractThe impacts of invasive plant control on native animals are rarely evaluated. Using data from an eight‐year study in southeastern Australia, we quantified the effects on native bird, mammal, and reptile species of (1) the abundance of the invasive Bitou Bush, Chrysanthemoides monilifera ssp. rotundata, and (2) a Bitou Bush control program, which involved repeated herbicide spraying interspersed with prescribed burning. We found that overall species richness of birds, mammals, and reptiles and the majority of individual vertebrate species were unresponsive to Bitou Bush cover and the number of plants. Two species including the nationally endangered Eastern Bristlebird (Dasyurus brachypterus) responded positively to measures of native vegetation cover following the control of Bitou Bush. Analyses of the effects of different components of the treatment protocol employed to control Bitou Bush revealed (1) no negative effects of spraying on vertebrate species richness; (2) negative effects of spraying on only one individual species (Scarlet Honeyeater); and (3) lower bird species richness but higher reptile species richness after fire. The occupancy of most individual vertebrates species was unaffected by burning; four species responded negatively and one positively to fire. Our study indicated that actions to remove Bitou Bush generally have few negative impacts on native vertebrates. We therefore suggest that controlling this highly invasive exotic plant species has only very limited negative impacts on vertebrate biota.

In the Shadow of Trees: Does Eucalyptus Afforestation Reduce Herpetofaunal Diversity in Southern Brazil?

Abstract. Tree cultivation is widely stimulated due to the provision of environmental services by sequestering atmospheric carbon, but forestry is a potential danger to biodiversity, mainly when cultivation replaces originally non-forested landscapes. Due to the rapid expansion of afforestation in grassland ecosystems, we used environmental descriptors and structure of amphibian and reptile communities as a tool to assess the possible effects of forestry on wildlife. We used pitfall traps with drift fences in Eucalyptus afforestation and native grasslands of the Pampa biome from southern Brazil. Amphibians and reptile species richness was lower in afforestation than in native grasslands. Furthermore, the reptile community found in afforestation was a poor subset of the community recorded in native grasslands. Indeed, the structure of communities for both amphibians and reptiles in afforestation was highly dissimilar from the native grasslands, with major environmental descriptors that influenced this diff...

Ecosystem Responses to Fire: Identifying Cross-taxa Contrasts and Complementarities to Inform Management Strategies

Changes in fire frequency, extent, and intensity mean that understanding the effects of fire on plants and animals is a primary concern for ecologists and land managers. Given the potentially conflicting fire responses of species both within and across taxonomic groups, prescribing fire regimes based on the response of one or only a few species may have negative consequences for other species. Here, we integrate data collected from a series of independent but complementary studies spanning a 75 + year chronosequence in a semi-arid shrubland ecosystem in south-western Australia to consider how fire management can best promote biodiversity both within and across taxonomic groups (plants, birds, small mammals, and reptiles). Younger fire ages (6–14 years) contained sparse shrubs, large areas of bare ground, and lacked a distinct litter layer and canopy. The oldest vegetation (60–85 years) had a distinct canopy, a well-developed litter layer and cryptogamic crust, higher variability in patch width, and more woody debris. Plant species richness and diversity decreased with time since fire, whereas bird species richness and diversity increased with time since fire, and mammal and reptile species richness and diversity showed no trend. The composition of all four taxonomic groups varied according to time since fire and the presence of 11 species was confined above or below certain fire-age thresholds. Our results support the need to maintain a mix of both younger and older fire ages across the landscape to maximise species diversity, and highlight the particular importance of older fire ages for many species. Future fire management for biodiversity conservation will benefit from identifying and reconciling cross-taxa contrasts and complementarities.

Factors influencing herpetofaunal assemblages of aquatic systems in a managed pine forest

Although >12 million ha of southeastern United States are intensively managed pine forest, we have little understanding of biological contributions of aquatic systems embedded in pine plantations. Further, the influence surrounding forest stand structure on assemblages of wetland-associated species in managed forests are poorly understood. To address these gaps, we investigated herpetofaunal assemblages across three ephemeral aquatic system types [unaltered sites (n=16), altered sites (n=18), and roadside ditches (n=19)] embedded in an intensively managed pine landscape in eastern North Carolina, USA. These aquatic systems varied in their disturbance intensity and landscape context. Unaltered sites were avoided by silvicultural activities (set aside), altered sites were actively managed as part of the surrounding plantation, and ditches received maintenance as part of routine forest management. We examined amphibian and reptile species richness and assemblage composition at 53 aquatic sites surrounded by early-, middle-, or late-rotation aged pine plantations. During January–July 2013 and January–June 2014, we detected 34 amphibian and reptile species with visual encounter, dipnet, and call surveys at aquatic sites. We estimated species richness and used Analysis of Similarity to assess differences in species richness and assemblage structure by aquatic system type and stand age class. Amphibian species richness was greatest in unaltered and altered sites but was similar among stand age classes. Reptile species richness was similar among aquatic system types and stand age classes. Analysis of Similarity results revealed that amphibian assemblages were similar among stand age classes but were significantly different among all aquatic systems. Reptile assemblages also were similar among stand age classes but differed between altered sites and roadside ditches. Differences between richness and assemblage results may have been related to low detections of reptiles because our non-metric multi-dimensional scaling analysis, which only included species with >1 detection, revealed less obvious differences among reptile assemblages by aquatic system type. Despite dramatic variation in disturbance intensity and site-level environmental metrics, we did not find distinct herpetofaunal assemblages among aquatic system types or stand age classes. Our results suggest that aquatic systems in reconfigured landscapes not only support a range of herpetofaunal species, but that amphibian and reptile assemblages are similar across system types.

Patterns of species richness, endemism and environmental gradients of African reptiles

AbstractAimTo map and assess the richness patterns of reptiles (and included groups: amphisbaenians, crocodiles, lizards, snakes and turtles) in Africa, quantify the overlap in species richness of reptiles (and included groups) with the other terrestrial vertebrate classes, investigate the environmental correlates underlying these patterns, and evaluate the role of range size on richness patterns.LocationAfrica.MethodsWe assembled a data set of distributions of all African reptile species. We tested the spatial congruence of reptile richness with that of amphibians, birds and mammals. We further tested the relative importance of temperature, precipitation, elevation range and net primary productivity for species richness over two spatial scales (ecoregions and 1° grids). We arranged reptile and vertebrate groups into range‐size quartiles in order to evaluate the role of range size in producing richness patterns.ResultsReptile, amphibian, bird and mammal richness are largely congruent (r = 0.79–0.86) and respond similarly to environmental variables (mainly productivity and precipitation). Ecoregion size accounts for more variation in the richness of reptiles than in that of other groups. Lizard distributions are distinct with several areas of high species richness where other vertebrate groups (including snakes) are species‐poor, especially in arid ecoregions. Habitat heterogeneity is the best predictor of narrow‐ranging species, but remains relatively important in explaining lizard richness even for species with large range sizes.Main conclusionsReptile richness varies with similar environmental variables as the other vertebrates in Africa, reflecting the disproportionate influence of snakes on reptile richness, a result of their large ranges. Richness gradients of narrow‐ranged vertebrates differ from those of widespread taxa, which may demonstrate different centres of endemism for reptile subclades in Africa. Lizard richness varies mostly with habitat heterogeneity independent of range size, which suggests that the difference in response of lizards is due to their ecological characteristics. These results, over two spatial scales and multiple range‐size quartiles, allow us to reliably interpret the influence of environmental variables on patterns of reptile richness and congruency.

Conservation of Terrestrial Vertebrates in a Global Hotspot of Karst Area in Southwestern China.

The karst area of southwest China (KASC) is the largest piece of karst landscape on the earth and a global biodiversity hot-spot with high concentrations of endemic species. Although a number of nature reserves (NRs) have been established across the region, the representativeness of biodiversity of the NR system is still unknown. Based on comprehensive literature and field surveys, and intensive consultations with zoologists and wildlife managers, we compiled distributions of 1,204 terrestrial vertebrate species and 271 NRs in KASC. We found Jinxiu, Mengla, Hekou, and Jinghong have the richest amphibian species; Jinxiu has the highest species richness of reptiles; Jinghong, Menghai, and Mengla have the largest numbers of avian species; whereas, Mengla, Longzhou, and Ningming have the greatest mammalian diversity in the region. Gap analysis among NR system, species richness pattern, and five biogeographic indicators found insufficient representation of the NR system on territorial vertebrate diversity. The conservation effectiveness in Guizhou Province was much lower than that in Guangxi and Yunnan Provinces. Under-representation and over-representation simultaneously occurred in many of the ecoregions, elevation classes, vegetation types, landcover categories, and human disturbance intensity gradients. For conservation of terrestrial vertebrates in KASC, several suggestions were presented in this study.

Influence of land sharing and land sparing strategies on patterns of vegetation and terrestrial vertebrate richness and occurrence in Australian endangered eucalypt woodlands

Native vegetation placed under an agri-environment scheme (AES) is purported to support greater biodiversity than vegetation managed for intensive livestock grazing, and conservation reserves are purported to support greater biodiversity than land sharing under AES. These predictions underpin financial incentive delivery programs that enable landholders to adopt environmentally friendly agricultural practices. To evaluate these predictions, we established a biodiversity monitoring program in endangered temperate eucalypt woodland communities in southern Australia. We compared vegetation variables and vertebrate species richness and abundance among sites under different land management between 2010 and 2014. Our sites included: (1) woodland remnants on private property recently placed under an AES land management agreement (land sharing), (2) woodland remnants in State conservation reserves as reference areas (land sparing), and (3) woodland remnants used for intensive livestock production as controls. We used hierarchical generalized linear models to examine patterns of biodiversity among management classes and over time. We found conservation reserves were structurally more complex and floristically richer compared to production sites, and AES supported greater cover of native perennial grass. Reptile and amphibian species richness and abundance, and total bird species richness did not differ significantly among management classes, although AES and reference sites supported more birds of conservation concern. Arboreal marsupials were significantly more species rich in conservation reserves than AES. Temporal patterns in vertebrate species richness were related to post-drought climatic conditions. Our findings suggest that strategies involving land sharing under AES are as effective as land sparing (e.g. conservation reserves) for bird conservation, but alternative strategies may be required to enhance habitat for less mobile species such as frogs and reptiles, or species dependant on old growth vegetation such as arboreal marsupials.

Incorporating regional‐scale ecological knowledge to improve the effectiveness of large‐scale conservation programmes

AbstractLand‐stewardship programmes are a major focus of investment by governments for conserving biodiversity in agricultural landscapes. These programmes are generally large‐scale (e.g. >1000 km) spanning multiple biogeographic regions but developed using spatially limited (e.g. landscape‐scale; <100 km) ecological data interpolated across broad areas for one, or a few, well‐studied taxonomic groups. Information about how less‐studied taxa respond to regional differences in management and environmental effects has potential to further inform land‐stewardship conservation programmes, but suitable data sets are rarely available. In this study, we sought to enhance planning of large‐scale conservation programmes by quantifying relationships between reptile assemblages and key environmental attributes at regional scales within a large‐scale (>172 000 km2) Australian land‐stewardship programme. Using 234 remnant woodland monitoring sites spanning four distinct biogeographic regions, we asked: Do reptile assemblages show different environmental associations across biogeographically distinct regions? We found that environmental features important to reptile diversity differed over each region. Abundance and rare species richness of reptiles responded at regional‐scales to elevation, native groundcover and aspect. We identified four implications from our study: (1) large‐scale conservation schemes can achieve better outcomes for reptiles using regional‐scale knowledge of environmental associations; (2) regional‐scale knowledge is particularly valuable for conservation of rare reptile taxa; (3) consideration of abiotic environmental features which cannot be directly managed (e.g. aspect, elevation) is important; (4) programmes can be tailored to better support reptile groups at higher conservation risk. Our study shows that reptile‐environment associations differ among biogeographic regions, and this presents opportunity for tailoring stronger policy and management strategies for conserving large‐scale agricultural landscapes globally.

Spatial Biodiversity Patterns of Madagascar's Amphibians and Reptiles.

Madagascar has become a model region for testing hypotheses of species diversification and biogeography, and many studies have focused on its diverse and highly endemic herpetofauna. Here we combine species distribution models of a near-complete set of species of reptiles and amphibians known from the island with body size data and a tabulation of herpetofaunal communities from field surveys, compiled up to 2008. Though taxonomic revisions and novel distributional records arose since compilation, we are confident that the data are appropriate for inferring and comparing biogeographic patterns among these groups of organisms. We observed species richness of both amphibians and reptiles was highest in the humid rainforest biome of eastern Madagascar, but reptiles also show areas of high richness in the dry and subarid western biomes. In several amphibian subclades, especially within the Mantellidae, species richness peaks in the central eastern geographic regions while in reptiles different subclades differ distinctly in their richness centers. A high proportion of clades and subclades of both amphibians and reptiles have a peak of local endemism in the topographically and bioclimatically diverse northern geographic regions. This northern area is roughly delimited by a diagonal spanning from 15.5°S on the east coast to ca. 15.0°S on the west coast. Amphibian diversity is highest at altitudes between 800–1200 m above sea-level whereas reptiles have their highest richness at low elevations, probably reflecting the comparatively large number of species specialized to the extended low-elevation areas in the dry and subarid biomes. We found that the range sizes of both amphibians and reptiles strongly correlated with body size, and differences between the two groups are explained by the larger body sizes of reptiles. However, snakes have larger range sizes than lizards which cannot be readily explained by their larger body sizes alone. Range filling, i.e., the amount of suitable habitat occupied by a species, is less expressed in amphibians than in reptiles, possibly reflecting their lower dispersal capacity. Taxonomic composition of communities assessed by field surveys is largely explained by bioclimatic regions, with communities from the dry and especially subarid biomes distinctly differing from humid and subhumid biomes.

Survey of the reptiles of the montane forests near Dorrigo on the north coast of New South Wales

Reptile surveys were conducted in the early 1990s in the Dorrigo Forest Management Area, an area formerly comprising timber-production forests managed by the Forestry Commission of New South Wales. The surveys consisted of searches for reptiles along 54 transects together with targeted surveys. Twenty-two 500 m transects were located in previously logged forest and 32 in unlogged forest. Each transect was surveyed twice at an average seven days apart in the spring-summer of 1993 by two persons simultaneously for a duration of 90 min each. A total of 26 reptile species were detected during systematic surveys and 22 reptile species during targeted diurnal searches and opportunistic sightings. The highest species richness and density of reptiles were recorded in the logged New England Hardwood and Gorge Red Gum forest types. The Moist Hardwood type, with a closed mid-canopy had the lowest reptile species richness and density. Neither species richness nor number of individuals varied significantly with loggin...

Rare alluvial sands of El Monte Valley, California (San Diego County), support high herpetofaunal species richness and diversity, despite severe habitat disturbance

Abstract We characterized the species richness, diversity, and distribution of amphibians and reptiles inhabiting El Monte Valley, a heavily disturbed, alluvium-filled basin within the lower San Diego River in Lakeside, California. This rare habitat type in coastal southern California is designated as a critical sand resource by the state of California and is currently under consideration for a large-scale sand mining operation with subsequent habitat restoration. We conducted field surveys from June 2015 to May 2016 using drift fence lines with funnel traps, coverboard arrays, walking transects, and road driving. We recorded 1,208 total captures, revealing high species richness and diversity, but with marked unevenness in species' abundances. Snakes were the most species-rich taxonomic group (13 species representing 11 genera), followed by lizards (11 species representing 9 genera). After the southern Pacific rattlesnake (Crotalus oreganus helleri), the California glossy snake (Arizona elegans occidental...

The importance of defining focal assemblages when evaluating amphibian and reptile responses to land use.

Habitat loss and degradation are primary threats to amphibians and reptiles, but the relative effects of common land uses on assemblages and the mechanisms that underlie faunal responses are poorly studied. We reviewed the effects of four prevalent types of habitat alteration (urbanization, agriculture, livestock grazing, and silviculture) on amphibian and reptile species richness and abundance by summarizing reported responses in the literature and by estimating effect sizes across studies for species richness in each land-use type. We then used a multinomial model to classify species as natural habitat specialists, generalists, and disturbed habitat specialists and examined variation in effect sizes for each land-use type according to habitat specialization categories. There were mixed conclusions from individual studies, some reporting negative, neutral, or positive effects of land use on species richness and total abundance. A large proportion of studies reported species-specific effects of individual species abundance. However, in our analysis of effect sizes, we found a general trend of negative effects of land use on species richness. We also demonstrate that habitat associations of common species and species turnover can explain variation in the effect of land use on herpetofauna. Our review highlights the pervasive negative effects of common land uses on amphibians and reptiles, the importance of identifying groups vulnerable to land-use change (e.g., forest-associated species) in conservation studies, and the potential influence of disturbance-associated species on whole assemblage analyses.

Patterns of reptile and amphibian species richness along elevational gradients in Mt. Kenya.

Faunal species richness is traditionally assumed to decrease with increasing elevation and decreasing primary productivity. Species richness is reported to peak at mid-elevation. This survey examines the herpetofaunal diversity and distribution in Mt. Kenya (central Kenya) by testing the hypothesis that changes in species richness with elevation relate to elevation-dependent changes in climate. Sampling along transects from an elevation of approximately 1 700 m in Chogoria forest block (wind-ward side) and approximately 2 600 m in Sirimon block (rain shadow zone) upwards in March 2009. This starts from the forest to montane alpine zones. Sampling of reptiles and amphibians uses pitfall traps associated with drift fences, time-limited searches and visual encounter surveys. The results show that herpetofaunal richness differs among three vegetation zones along the elevation gradient. Chogoria has higher biodiversity than Sirimon. More species occur at low and middle elevations and few exist at high elevations. The trends are consistent with expected optimum water and energy variables. The lower alpine montane zone has high species richness but low diversity due to dominance of some high elevations species. Unambiguous data do not support a mid-domain effect (mid-elevation peak) because the observed trend better fits a model in which climatic variables (rainfall and temperature) control species richness, which indirectly measures productivity. It is important to continue protection of all indigenous forests, especially at low to mid elevations. These areas are vulnerable to human destruction yet are home to some endemic species. Firebreaks can limit the spread of the perennial wildfires, especially on the moorlands.