Diversity of Carabidae (Insecta, Coleoptera) in epiphytic Bromeliaceae in central Veracruz, Mexico

This paper documents the existence of carabid assemblages associated with bromeliads on the Cofre de Perote, Veracruz, Mexico. Based on bromeliads sampled over three altitudinal ranges, the assemblages included at least 26 species with an arboreal lifestyle and another 11 species that are not strictly arboreal. Seven species are new to science, urging us to pay attention to the arboreal fauna in forest conservation studies. Composition of carabid assemblages associated with bromeliads changes with altitude. In lowlands, it is comprised almost entirely of species of Lebiini, with the Platynini dominating assemblages found in bromeliads >1,000 m above sea level. Our data suggest that carabids use bromeliads to reduce stresses associated with drought periods, the exact timing of which depends on altitude. The unexpected low diversity of the carabid fauna associated with bromeliads at middle altitude is explained in terms of anthropogenic conversion of the original forest to pastureland. Given the importance of arboreal elements, further fragmentation of subtropical and tropical mountain forest significantly threatens overall carabid diversity.     

Distribution of ground-dwelling beetles in fragmented tropical habitats

The conservation of biodiversity is increasingly dependent on human-altered habitats. In a fragmented forest landscape in northern Costa Rica within the Mesoamerican Biological Corridor, an area of great conservation importance, we compared the diversity and composition of ground-dwelling beetle communities in five habitat types along a gradient of increasing disturbance: primary forest, logged forest, secondary forest, plantation (Gmelina arborea) and pasture. Using pitfall trapping we captured a total of 1,877 beetles (Coleoptera), comprising 422 morphospecies in 26 families. The plantation sites had the lowest number of species followed by secondary forest and pasture. Multivariate analysis separated the beetle fauna according to land use, and suggested that only the logged forest maintains a similar species assemblage to primary forest. However, each habitat harboured a number of unique species indicating the conservation value of the mosaic of habitats found in fragmented landscapes. Our results suggest that to maintain forest beetle species diversity it is essential that areas of natural forest are conserved. However, other land uses also provide beetle habitats and in fragmented areas active management to maintain a mosaic of land uses will contribute to the conservation of beetle diversity.     

Abrupt species loss of the Amazonian dung beetle in pastures adjacent to species-rich forests

Anthropogenic disturbances, such as conversion of forests to pastures, are considered one of the major causes of Amazonian biodiversity loss. Pastures are hostile environments for forest species that are not adapted to the adverse conditions of open areas. The aim of this study was to analyze the effects of forest replacement by cattle pastures in the north-eastern part of the Amazonian rainforest using dung beetles (Scarabaeidae: Scarabaeinae) as indicators. Therefore, we determined edge effects and differences in dung beetle species richness, composition, and abundance between forest and neighbouring cattle pastures. A total of 6723 individuals of 63 species of dung beetle were collected. In comparison to forests, adjacent pastures were sharply less rich and abundant in dung beetles. The forests had 6604 individuals and 59 species, while the pastures had 119 individuals and 12 species. The replacement of forests by pastures results in an increase of dung beetle species turnover. Only 12% of dung beetle species were shared by both forest and pasture environments. We highlight that most Amazonian dung beetles are forest species sensitive to abrupt human-driven modification of habitats and are only moderately affected by edge effects.     

The maintenance of extensively exploited pastures within the Alpine mountain belt: implications for dung beetle conservation (Coleoptera: Scarabaeoidea)

The abandonment of marginal areas and the decline of traditional small-scale cattle-breeding is bringing about substantial changes in many areas of the Alpine mountain belt. Extensively exploited pastures, which were colonized by typical ecological communities, are now being replaced by shrublands and forests. In this paper, we evaluate the effectiveness of the maintenance of small pastures for dung beetle (Scarabaeoidea: Geotrupidae, Aphodiidae, Scarabaeidae) conservation in a protected area of the north-western Italian Alps. From July until September 2007, we studied the dung beetle coenosis in the main habitats of the mountain belt: beech forest, scots pine forest, mountain pine forest and pasture. Twenty-three species were sampled. We compared abundance, species richness, α-diversity, evenness and species turnover between the four habitat assemblages and performed a correspondence analysis based on dominance patterns of the three families. Two main ensembles were identified: a pasture ensemble, highly diverse and dominated by Scarabaeidae, and a closed habitats ensemble, less structured and dominated by Aphodiidae and Geotrupidae. Combining habitat specificity and fidelity, the IndVal method showed that half of the species collected made a strong habitat selection toward pasture, while only C. granarius (Aphodiidae) was a reliable indicator of woody areas. We therefore conclude that the loss of extensively exploited pastures may bring about fundamental changes in dung insect communities. In protected areas, a management policy intended to preserve the traditional, sustainable human activities within the mountain belt is highly recommended for the conservation of these insects.     

Diversity and biogeographical makeup of the dung beetle communities inhabiting two mountains in the Mexican Transition Zone

The role of horizontal and vertical colonization on the diversity and integration of the dung beetle fauna of two mountains in the Mexican Transition Zone (Los Tuxtlas and La Chinantla) are analyzed and compared. On each mountain standardized sampling was done using pitfall traps baited with dung and carrion along elevation gradients. On both mountains diversity decreased linearly with increasing elevation. The decrease in the number of genera and species was not different between mountains, but the cumulative total number for both taxonomic levels was significantly higher on La Chinantla. There, three well-defined groups were identified for which species turnover was mainly a result of species gain. On Los Tuxtlas there was no evident grouping pattern, and species turnover was determined by species loss. For both mountains the dominant biogeographic distribution pattern was Neotropical; however, at the higher elevations of La Chinantla, a clear replacement by lineages of Holarctic affinity was observed. We suggest that for La Chinantla—a mountain that is geographically connected to the Sierra Madre Oriental mountain range and is of ancient geological origin—the processes of horizontal and vertical colonization have had relatively different weights in terms of their effect on the pattern of diversity and the biogeographic integration of the beetle community, while on Los Tuxtlas, the limited role of horizontal colonization appears to be a consequence of its isolation and more recent geological origin. We discuss the potential use of these models for studying the effects of climate change on elevation gradients.     

Altitudinal variation of dung beetle (Scarabaeidae: Scarabaeinae) assemblages in the Colombian Andes

Aim We describe the changes in species richness, rarity and composition with altitude, and explore whether the differences in Scarabaeinae dung beetle composition along five altitudinal transects of the same mountain range are related to altitude or if there are interregional differences in these altitudinal gradients. Location Field work was carried out on the eastern slope of the eastern Cordillera, Colombian Andes, between Tamá Peak to the north, in the Tamá National Park (07°23′ N, 72°23′ W) and the San Miguel River (00°28′ N, 77°17′ W) to the south. Methods Sampling was carried out between February 1997 and November 1999 in five regions spanning elevation gradients. In each gradient, six sites were chosen at 250 m intervals between 1000 and 2250 m a.s.l. Results We found a curvilinear relationship between altitude and mean species richness, with a peak in richness at middle elevations. However, the diversity of dung beetle assemblages does not seem to be related to the interregional differences in environmental conditions. The number of geographically restricted species is negatively and significantly related to altitude, with geographically restricted species more frequent at low altitude sites. Ordination delimited the two main groups according to altitude: one with all the highest sites (1750–2250 m a.s.l.) and a second group with the remaining sites (< 1750 m a.s.l.). Analysis of species co‐occurrence shows that these dung beetle assemblages seem to be spatially structured when all sites have the same probability of being chosen. In contrast, the spatial structure of species assemblages seems to be random when the probability of choosing any site is proportional to its altitude. Main conclusions The altitude of sites is the main factor that influences the diversity of these dung beetle assemblages. The peak in species richness at middle elevations, the higher number of geographically restricted species at lower altitudinal levels, and the compositional differences along these mountain gradients seem to result from the mixing at these altitudes of dung beetle assemblages that have different environmental adaptations and, probably, different origins. The relevance of altitude in these assemblages is related to the limited role of these Neotropical high altitude environments as centres of refuge and vicariance for a monophyletic group of warm‐adapted species, for which the vertical colonization of these high mountain environments by lineages distributed at lower altitudes would have been very difficult.     

Does natural reforestation represent a potential threat to dung beetle diversity in the Alps?

Traditional agro-pastoral practices are in decline over much of the Alps, resulting in the complete elimination of livestock grazing in some areas. Natural reforestation following pastoral abandonment may represent a significant threat to alpine biodiversity, especially that associated with open habitats. This study presents the first assessment of the potential effects of natural reforestation on dung beetles by exploring the relationships between the beetle community (abundance, diversity, species turnover and assemblage structure) and the vegetation stages of ecological succession following pastoral abandonment. A hierarchical sampling design was used in the montane belt of the Sessera Valley (north-western Italian Alps). Dung beetles were sampled across 16 sampling sites set in four habitat types corresponding to four different successional stages (pasture, shrub, pioneer forest and beech forest) at two altitudinal levels. The two habitats at the extremes of the ecological succession, i.e. pasture and beech forest, had the greatest effect on the structure of local dung beetle assemblages. Overall, dung beetle abundance was greater in beech forest, whereas species richness, Shannon diversity and taxonomic diversity were significantly higher in pasture, hence suggesting this latter habitat can be considered as a key conservation habitat. Forests and pastures shared a lower number of species than the other pairs of habitats (i.e. species turnover between these two habitats was the highest). The two intermediate seral stages, i.e. shrub and pioneer forest, showed low dung beetle abundance and diversity values. Local dung beetle assemblages were also dependent on season and altitude; early-arriving species were typical of pastures of high elevation, whereas late-arriving species were typical of beech forests. It is likely that grazing in the Alps will continue to decrease in the future leading to replacement of open habitats by forest. This study suggests therefore that, at least in the montane belt, reforestation may have potentially profound and negative effects on dung beetle diversity. Maintaining traditional pastoral activities appears to be the most promising approach to preserve open habitats and adjacent beech forests, resulting in the conservation of species of both habitats.     

Community Structure of Skipper Butterflies (Lepidoptera,Hesperiidae) along Elevational Gradients in Brazilian Atlantic Forest Reflects Vegetation Type Rather than Altitude

Species turnover across elevational gradients has matured into an important paradigm of community ecology. Here, we tested whether ecological and phylogenetic structure of skipper butterfly assemblages is more strongly structured according to altitude or vegetation type along three elevation gradients of moderate extent in Serra do Mar, Southern Brazil. Skippers were surveyed along three different mountain transects, and data on altitude and vegetation type of every collection site were recorded. NMDS ordination plots were used to assess community turnover and the influence of phylogenetic distance between species on apparent community patterns. Ordinations based on ecological similarity (Bray-Curtis index) were compared to those based on phylogenetic distance measures (MPD and MNTD) derived from a supertree. In the absence of a well-resolved phylogeny, various branch length transformation methods were applied together with four different null models, aiming to assess if results were confounded by low-resolution trees. Species composition as well as phylogenetic community structure of skipper butterflies were more prominently related to vegetation type instead of altitude per se. Phylogenetic distances reflected spatial community patterns less clearly than species composition, but revealed a more distinct fauna of monocot feeders associated with grassland habitats, implying that historical factors have played a fundamental role in shaping species composition across elevation gradients. Phylogenetic structure of community turned out to be a relevant additional tool which was even superior to identify faunal contrasts between forest and grassland habitats related to deep evolutionary splits. Since endemic skippers tend to occur in grassland habitats in the Serra do Mar, inclusion of phylogenetic diversity may also be important for conservation decisions.     

Spathacanthus magdalenae sp. nov. (Acanthaceae), a riparian forest species from Veracruz,Mexico

Spathacanthus magdalenae Cast.‐Campos (Acanthaceae) is described and illustrated as a new riparian forest species from central Veracruz and from the eastern slopes of the volcano Cofre de Perote, Mexico. The new species is similar to Spathacanthus parviflorus, but differs in wider leaves and longer corolla tube. A key to all four species of Spathacanthus is provided.     

Diversity patterns of the terrestrial snail fauna of Nyungwe Forest National Park (Rwanda), a Pleistocene refugium in the heart of Africa

We investigated the land snail fauna of Nyungwe Forest National Park in south‐western Rwanda. Fifty plots at altitudes between 1718 and 2573 m were studied. In total, 3461 specimens were collected and were assigned to 102 land snail species. With respect to land snail species, Nyungwe Forest is the richest forest known in Africa. A comparison with other forests in the northern Albertine Rift indicates that land snail species richness in this region is significantly correlated with distance from Pleistocene forest refugia. The high beta diversity in Nyungwe is the result of a high species turnover between sites, which has biogeographical and ecological origins. Nyungwe Forest is situated on the Congo–Nile divide where species of different geographical origin may meet. Moreover, Nyungwe Forest offers a high diversity of habitats because it extends across a wide range of altitudinal zones. Species richness decreased with increasing altitude. It was also correlated with the presence of bare rocks that offer additional microhabitats and shelter. Although the occurrences of different land snail species in Nyungwe Forest were significantly clustered, only a minority of the species could be assigned to a group of species with similar occurrences. The majority of the species respond individualistically to environmental variables. The significant nestedness of the occurrences of the land snail species in Nyungwe was mainly correlated with altitude. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 363–375.     

Response of rove beetles (Staphylinidae) to various habitat types and change in Southern Mexico

We evaluated changes in levels of diversity of copro-necrophilous staphylinids attracted to piles of cattle dung and rat carrion in four contrasting habitats (continuous oak forest, oak forest patches, savannah and ravines) in southeastern Mexico during 2005 and 2006. In total, 181 morpho-species (N = 9,875 individuals) of Staphylinidae were recorded, of which 40 were coprophiles, 98 were necrophiles, and 43 were present in both substrates. Ten species accounted for 65% of the total number of individuals, 68 species were represented by singletons, whereas 103 species registered intermediate abundances. Less disturbed habitats recorded higher levels of beetle diversity. A strong seasonality effect was recorded for necrophiles, but not for coprophiles. A beta diversity analysis suggested that continuous oak forest registered the lowest fauna similarity when contrasted to other habitats; yet beetle composition among oak forest patches, savannah and ravine remained comparable. Staphylinidae body size and trophic guilds differed significantly among habitats. The results of this study suggest that key habitats such as ravines may represent a more permanent and predictable habitat for beetles in highly seasonal landscapes, even at early stages, because this habitat is characterized by a slower turnover of Staphylinidae species than in the case of tropical oak patches or savannah habitats.     

Assessing the origin of Neotropical mountain dung beetle assemblages (Scarabaeidae: Scarabaeinae): the comparative influence of vertical and horizontal colonization

Aims The fauna of mountains and their surrounding regions are likely to be influenced principally by two biological processes: horizontal colonization along similar altitudinal levels by elements originating from lineages inhabiting higher latitudes; and vertical colonization by lineages from the same latitude, but at lower altitudes. We examine whether the expected patterns derived from the latter process can be observed in mountain dung beetle assemblages. Specifically, we study the variation in species composition and richness with altitude in five regions spanning elevation gradients, analysing whether the altitudinal rates of change in the number of species and genera differ, and whether beta‐diversity scores for adjacent sites in each altitudinal gradient are different for species and genera. Location Eastern Cordillera of the Colombian Andes. Methods Field work was carried out in 1997–99 at 27 sites in five regions with elevation gradients, with 10–32 pitfall traps placed in each site. For each altitudinal level the numbers of species and genera were analysed with respect to altitude, and the slope of the linear regression between these variables was calculated. The slope of the curve of the altitude against the cumulative number of species and genera was also calculated for each altitudinal gradient to describe the compositional change between adjacent sites (beta diversity). Species and generic slopes were compared using analysis of covariance. The turnover of species along each altitudinal gradient was measured using presence/absence data and Cody's beta‐diversity index between adjacent pairs of sites. A cluster analysis was used to detect faunistically homogeneous groups of localities. Results Species richness always decreased with altitude, although the slopes did not differ significantly from zero. The number of genera also decreased with increasing altitude, but generally at a significantly slower rate than for species. Variation in the species beta‐diversity scores between altitudinal levels did not follow a homogeneous pattern in the different regions. Two main altitudinal groups of sites with a boundary c. 1500–1750 m a.s.l. can be detected with respect to faunistic similarity. Low‐ and mid‐altitude sites are inhabited by all of the genera (19) and 80% of all species collected. Eight genera and 61 species (c. 60% of the total) are unable to inhabit high‐altitude sites, and only 20 species appear to be exclusive to these high‐altitude environments (> 2000 m a.s.l.). Main conclusions The dominant processes explaining dung beetle composition in the high north‐eastern Andean mountains are probably those of vertical colonization. The limited role of horizontal colonization processes, or colonization from northern or southern lineages, could be a consequence of the isolation and recent geological origin of these mountains.     

Does the composition of Scarabaeidae (Coleoptera) communities reflect the extent of land use changes in the Brazilian Amazon?

Scarab beetles (Coleoptera: Scarabaeidae) have been used to investigate the effects of environmental disturbances on forest structure and diversity. This group is recognized as sensitive to habitat perturbations and ecosystem changes. Here we examine the effects of anthropogenic impacts on Scarabaeidae composition, testing the following hypotheses: (1) Scarab beetle communities react to land use disturbances with predictable trends, (2) disturbed habitats are able to retain only a part of the Scarab beetle community of native forests or late secondary forests; (3) habitats largely differ in terms of species richness, taxonomic diversity and ecological composition, supporting exclusive and indicator species. We selected areas of native forest, agriculture, pasture for extensive livestock and secondary forests in different stages of regeneration. Our results show that the Scarabaeidae species were not indifferent to the gradient of structural changes represented by the studied areas. In fact, their patterns of habitat preference reveals communities more abundant and diverse in pristine habitats. In contrast, disturbed habitats, dominated by agricultural activities and pasture, indicated clear detrimental effects on the abundance of all forest Scarab beetle specialists. On the other hand, the generalist species, mainly associated with open environments, seemed to be favoured by the prevailing conditions induced by agricultural activities. Overall, the composition of the Scarab beetle communities is variable and sensitive to those structural gradients and, therefore, capable of responding as useful ecological indicators for assessing the extent of land use change or degradation.     

How dung beetles respond to a human‐modified variegated landscape in Mexican cloud forest: a study of biodiversity integrating ecological and biogeographical perspectives

Aim To analyse how the dung beetles (Scarabaeinae) respond to a modified, variegated landscape, taking into account the biogeographical peculiarities of the Mexican Transition Zone. Location This study covers cloud forest (CF) of the Sierra Norte de Puebla mountain range and part of the Sierra Madre Oriental mountain range (Mexico). Methods We applied proportional sampling based on the landscape variegation model with Scarabaeinae as the indicator group, and using two approaches: structural units (vegetation type) and spatial units (windows). We used two measures – richness and Shannon diversity – and applied multiplicative diversity partitioning to obtain independent alpha and beta diversities for the landscape, windows and vegetation types. We grouped species by biogeographical distribution pattern for the biogeographical analysis and by whether they were originally from CF. Results The transformation of CF into secondary forest, pastures and other types of vegetation increases the Scarabaeinae diversity of the landscape, in vegetation types and windows. This increase is the result of species arriving from the tropical lowlands. However, the original dung beetle community of the CF dominates at different scales in the number of species, abundance and biomass. With increasing habitat modification, beta diversity increases in the windows, and species with the Tropical Palaeoamerican distribution pattern increase in abundance in vegetation types and windows. Main conclusions The variegated character of the landscape explains well the distribution and diversity of this dung beetle community. The peculiar characteristics of the Mexican Transition Zone have an effect owing to the overlap of fauna with different biogeographical origins. The conversion of fragmented landscapes to variegated landscapes could be a conservation goal in human‐modified mountain landscapes. Sampling proportional to the area of different types of vegetation and the use of windows offer an alternative experimental design in variegated landscapes.     

Dung beetles in pasture landscapes of Central America: proliferation of synanthropogenic species and decline of forest specialists

This study examines the spread of synanthropogenic dung beetles (species favoured by human activities) in pasture landscapes in Central America, and evaluates the role of forest fragments and regenerating patches of native vegetation in maintaining beetle diversity. Pitfall trapping was carried out at nine locations in El Salvador and seven in Atlantic Nicaragua that included both pasture and remnant or regenerating native vegetation. More dung beetle species occurred in forest fragments than in pastures. Community composition differed considerably between forest fragments from El Salvador and Nicaragua with many species restricted to either the Caribbean or Pacific regions. In contrast, dung beetle community composition and structure were largely the same in the pastures of El Salvador and Nicaragua, regardless of region or original habitat-type, and were similar to published results from pastures in Mexico and elsewhere on the Isthmus. Very small patches of native shrubs and tree stands (<2.5 ha) maintained no forest specialists in Nicaragua, whereas, in El Salvador, some forest specialists occurred even in the smallest stands of trees (ca. 0.25 ha). The study indicates that the expansion of cattle pastures has caused a regional decline in dung beetle diversity. Forest fragments and small isolated patches of native trees and shrubs maintain some of the diversity of the original landscape but their conservation value for dung beetles will depend on the biogeographical history of the sites.     

From lowlands to highlands: searching for elevational patterns of species richness and distribution of scarab beetles in Costa Rica

Aim Understanding the heterogeneous distribution of species on mountains is an important aim in ecology. Altitudinal gradients have enormous potential for improving our knowledge of trends in biodiversity and conservation. In this study, we investigated the variation in scarab beetle diversity (Dynastinae, Rutelinae and Melolonthinae) along an elevational tropical forest gradient. Location The Atlantic slope of the Guanacaste mountain range in Costa Rica. Methods Ultraviolet light traps placed in six forests situated from 100 to 1510 m were used. Changes in species composition and richness among elevations were investigated. Differences in the altitudinal patterns using different groups of species were examined: the whole assemblage, each separate subfamily and two different trophic habits (phytophagous or saproxylic). The effects of temperature, humidity and elevation on scarab distribution were tested using canonical correspondence analyses. The relationship between the community similarity of the studied forests and the altitudinal distance among them was also analysed. Results Species composition and richness changed along the gradient. The peak in species richness varied depending on the species group considered and in all cases occurred 500 or 800 m. Forests at these altitudes were also the richest in exclusive species. Species composition turnover among elevations appeared with a clear separation between lowland and highland fauna. The latter was lower in richness but also had exclusive species. Temperature, humidity and altitude affected species distribution, with altitude being the most important factor for all the subfamilies studied. Main conclusions Our results showed that species distribution fits a hump‐shaped pattern. The peak of this pattern varied depending on the taxonomic group and mountain analysed, highlighting the importance of evolutionary processes as species distribution drivers. The fact that species richness peaked at elevations where human impact is currently important underlines the value of the development of conservation strategies for these areas.     

Dung beetle community composition affects dung turnover in subtropical US grasslands

1. An important service in many ecosystems is the turnover and degradation of dung deposited by cattle. Dung beetles are the primary group of insects responsible for dung turnover, and factors affecting their abundance and distribution thus impact dung degradation. Lands lost to grazing due to dung buildup and pasture contamination total millions of acres per year in US pastures.
2. We evaluated the structural differences in dung beetle assemblages in natural grasslands versus a managed agroecosystem in subtropical southeastern Florida (USA). We measured the direct effect of dung longevity when dung beetle fauna normally inhabiting dung pats were excluded.
3. Our results indicate dung beetle abundance, functional diversity, and species richness have a substantial impact on the rate of dung turnover in subtropical pastoral lands with ~70% of dung removed from the soil surface after three months. Functional diversity and evenness did not have a significant positive effect on dung removal in managed, versus natural grasslands demonstrating a strong relationship between dung beetle assemblage composition and delivery of a key ecological process, dung degradation.
4. We suggest the importance of trees, which provide a thermal refuge for beetles, should be dispersed within matrixes of open pasture areas and within proximity to adjacent closed‐canopy hammocks to facilitate the exchange of dung beetles between habitats and therefore maintain the provisioning of dung degradation services by dung beetle assemblages.

     

Biological diversification in a complex region: a spatial analysis of faunistic diversity and biogeography of the Andes of Colombia

Aim Understanding large‐scale patterns of beta diversity and endemism is essential for ecoregional conservation planning. We present a study of spatial patterns of faunal diversification and biogeographical relationships in the Andean region of Colombia. This region has a great geomorphological complexity, as it is formed by several mountain ranges with different geologic origins. We hypothesize that this complexity results in a high turnover in species composition among subregions. Location The Andean region of Colombia, including the Santa Marta and Macarena mountain ranges. Methods The region was divided into subregions, represented by the eastern and western slopes of each of the three Andean cordilleras, the Cauca and Magdalena valley bottoms, and the peripheral mountain ranges of Perijá, Macarena and Sierra Nevada de Santa Marta. Species lists for five animal taxa (rodents, bats, birds, frogs and butterflies) were compiled for each subregion and similarities in species composition were determined by cluster analysis. To explore biogeographical relationships, species were classified into one of four distributional categories: endemic, tropical Andean, Andean‐Central American and wide continental distribution. Results The highest species richness in the region was found in the Pacific and eastern versants of the Andes, and the lowest in the Cauca and Magdalena valley bottoms. Inter‐Andean slopes were intermediate in species richness. However, when species richness was calculated per unit area, the most diverse regions were the Santa Marta and Macarena ranges, the Cauca Valley watershed and the Pacific slope. Although each taxonomic group had a different branching pattern, dendrograms indicated five common subregional clusterings: (1) Perijá‐Sierra Nevada, (2) the Pacific slope, (3) the eastern Andean slope, (4) the Cauca and Magdalena valley bottoms, and (5) the inter‐Andean slopes. Clustering patterns of inter‐Andean slopes varied among taxa. In birds, bats and rodents, grouping was by opposite slopes of the same valley, whereas frogs were grouped by mountain ranges and butterflies by valleys and their respective slopes. Seventy‐five per cent of species in all taxa were found in less than five subregions. The fauna of the Magdalena and Cauca valley bottoms was composed mostly of lowland species with wide geographical distributions, whereas the cordilleran fauna was mostly restricted to the tropical Andes. Main conclusions The western and eastern versants of the Andes have the highest species richness, but are also the largest subregions. On a per unit area basis, the peripheral ranges (Santa Marta and Macarena) are the richest, followed by the western portion of the Andes (the Cauca Valley watershed and the Pacific versant). Clustering patterns in dendrograms suggest two major patterns of differentiation of the Andean fauna: one elevational (lowlands vs. highlands) and one horizontal (among ranges and/or slopes). Biogeographical affinities of the inter‐Andean valley bottoms are with the lowland faunas of tropical America. In contrast, Andean faunas diversified locally, resulting in the evolution of a large number of endemic species, particularly among the less vagile taxa. Three different main branches of Andean fauna can be recognized, one confined to the Pacific, another to the eastern (Amazonian‐Llanos) versant of the Andes, and the third one composed by the inter‐Andean slopes of the Cauca and Magdalena valleys. The identification of five main biogeographical units in the Andean region of Colombia has important implications for the conservation of the regional biota. Conservation initiatives that seek to preserve representative samples of the regional biodiversity should take into account the patterns of diversification described here, and the evolutionary processes that gave rise to these patterns.     

Hunting Spiders of Woodland Fragments and Agricultural Habitats in the Atlantic Rain Forest Region of Brazil

The hunting spider communities of the Dionycha clade were studied 1986 through 1988 in fragmented woodlands and secondary agricultural habitats of the Botucatu area in São Paulo state, Brazil. The original vegetation of mainly tropical Atlantic rain forest (Mata Atlântica) was cleared already 70 years ago. In a total sample of over 1000 adult spiders, 247 species belonging to 12 families were determined. A decreasing frequency and diversity of spiders was found if forest remnants were compared with sugar cane fields and cattle pasture. The specific composition of the spider fauna as surveyed in different habitats is discussed under ecological aspects and in relation to the history of land use.     

Beetle assemblages of kahikatea forest fragments in a pasture- dominated landscape

Fragments of kahikatea (Dacrycarpus dacrydioides) forest provide a major opportunity for conservation of indigenous biodiversity in the heavily deforested landscape of the Waikato Basin, New Zealand. However, there is little documented information on what indigenous fauna survives in these fragments. Using Malaise traps set 20 m and 50 m into fragments and 20 m and 50 m into the adjacent pasture, we analysed the beetle (Coleoptera) assemblages associated with two such kahikatea forest fragments in the south Waikato Basin in order to determine the scope of biotic invasion by adventive species and use of the surrounding pasture by indigenous species. A total of 3706 beetles were caught, encompassing 37 families and 206 recognisable taxonomic units. The forest fragments had a sharply defined edge, and were dominated by indigenous beetle species, with only a few adventive species present. Beetle assemblages sampled in the surrounding pasture were numerically dominated by adventive species. Despite no indigenous plant species being present in the pastures, 55 indigenous beetles species (61% of total species sampled in the pasture) were recorded in this habitat. Traps in the pasture of greatest floral diversity caught the most indigenous beetle species. Beetles of the detritivore guild dominated the samples from forest, but in samples from pasture, detritovores and predatores were co-dominant. Indigenous herbivore species were poorly represented in samples from pasture compared to other guilds. The kahikatea fragments have a rich indigenous beetle fauna and represent important refuges in the pastoral landscape of the Waikato. Many indigenous species are utilising the pasture to some degree, although their abundance and species richness declines with distance from the forest edge. This may have implications for successful dispersal to new patches. Species that could potentially be used as indicators of kahikatea forest fragment community structure and its resistance to invasion are suggested.