Effects of creation of open vegetation in abandoned terraced paddy fields on carabid beetle assemblages in temperate Japan

Many paddy fields in the mountainous rural areas of Japan have been abandoned since the 1960s, and forests have regenerated on these sites. In a mountainous area on Sado Island, a large number of abandoned paddies were converted into wetlands and open terrestrial vegetation. In this study, we used pitfall traps to examine the effects of the creation of open vegetation on carabid beetle assemblages by investigating 14 sites spanning five vegetation types: six sites in secondary forests (three coppice forests and three 40‐year‐old regenerating forests on abandoned paddies), three each in clear‐cuts and paddy levees, and two in grasslands. The 14 study sites were clearly separated into two groups different in the species composition of carabid beetles: secondary forest and grassland‐levee groups. The species composition of two clear‐cut sites was similar to that of secondary forests, whereas that of the remaining one clear‐cut site was similar to that of grasslands. Analyses of species responses showed various habitat preferences, e.g., for only coppice forests, for two types of secondary forests, for secondary forests and clear‐cuts, for clear‐cuts and grasslands, and for grasslands or levees, or no clear preference. There were no characteristic species in the regenerating forests. These results suggest that the 40‐year‐old regenerating forests may sustain only a limited subset of the carabid fauna found in coppice forests and that the creation of open vegetation in the abandoned paddies enhances carabid diversity at the landscape level by raising β diversity among the different vegetation types.     

Land-Use History and Forest Regeneration in the Cayey Mountains, Puerto Rico

Although deforestation continues to be a major threat to tropical biodiversity, abandonment of agricultural land in Puerto Rico provides an opportunity to study long-term patterns of secondary forest regeneration. Using aerial photographs from 1937, 1967, and 1995, we determined land-use history for 2443 ha in the Cayey Mountains. Pastures were the dominant land cover in 1937 and <20% of the area was classified as forest. Between 1937 and 1995, forest cover increased to 62% due to widespread abandonment of agriculture. To examine the effect of historic land use on current forest structure and species composition, we sampled secondary forests in 24 abandoned pastures, 9 abandoned coffee plantations and 4 old-growth forest sites. Sites were located on two soil types along an elevational gradient (125–710 m) and included a chronosequence from 4 to over 80 years old. After 25–30 years, basal area and species richness in secondary forest sites derived from abandoned pastures and coffee plantations were similar to old-growth forest sites. The species composition of secondary forests derived from abandoned pastures and coffee plantations remained distinct from old-growth forest. In addition to historic land use, age and elevation were important environmental variables explaining variation in secondary forest species composition. Non-indigenous species were common in recently abandoned pastures and coffee plantations, but their importance declined in the older sites. This study demonstrates that secondary forests on private land can be an important component of the conservation of tropical tree biodiversity. Received 16 June 1999; Accepted 8 October 1999.     

The role of novel forest ecosystems in the conservation of wood‐inhabiting fungi in boreal broadleaved forests

The increasing human impact on the earth's biosphere is inflicting changes at all spatial scales. As well as deterioration and fragmentation of natural biological systems, these changes also led to other, unprecedented effects and emergence of novel habitats. In boreal zone, intensive forest management has negatively impacted a multitude of deadwood‐associated species. This is especially alarming given the important role wood‐inhabiting fungi have in the natural decay processes. In the boreal zone, natural broad‐leaved‐dominated, herb‐rich forests are threatened habitats which have high wood‐inhabiting fungal species richness. Fungal diversity in other broadleaved forest habitat types is poorly known. Traditional wood pastures and man‐made afforested fields are novel habitats that could potentially be important for wood‐inhabiting fungi. This study compares species richness and fungal community composition across the aforementioned habitat types, based on data collected for wood‐inhabiting fungi occupying all deadwood diameter fractions. Corticioid and polyporoid fungi were surveyed from 67 130 deadwood particles in four natural herb‐rich forests, four birch‐dominated wood pastures, and four birch‐dominated afforested field sites in central Finland. As predicted, natural herb‐rich forests were the most species‐rich habitat. However, afforested fields also had considerably higher overall species richness than wood pastures. Many rare or rarely collected species were detected in each forest type. Finally, fungal community composition showed some divergence not only among the different habitat types, but also among deadwood diameter fractions. Synthesis and applications: In order to maintain biodiversity at both local and regional scales, conserving threatened natural habitat types and managing traditional landscapes is essential. Man‐made secondary woody habitats could provide the necessary resources and serve as surrogate habitats for many broadleaved deadwood‐associated species, and thus complement the existing conservation network of natural forests.     

Effects of agricultural soil loss on forest succession rates and tree diversity in east Tennessee

All land on what is today the Oak Ridge Reservation, Tennessee, was abandoned in 1942 when the United States government acquired the land for atomic weapons development. Most of the land now serves as a buffer around the government facilities and has not been managed, providing an opportunity to study forest succession on simultaneously abandoned fields. We sampled forest vegetation and soils on former pastures that had sustained varying levels of pre-abandonment soil loss. The most eroded sites are still covered with forests of an early-successional composition, with shortleaf pine ( Pinus echinata ) and Virginia pine ( P. virginiana ) dominating. Hardwoods, particularly oaks ( Quercus ) and hickories ( Carya ), dominate the least degraded former pastures. Canopy tree species diversity is highest at the least degraded sites, which also have the highest levels of soil nitrogen. These results suggest that soil degradation reduces the rate of secondary succession and thereby slows the increase in species diversity typical of early forest succession, while increasing the spatial complexity of the landscape.     

Restoring montane cloud forest: establishment of three Fagaceae species in the old fields of central Veracruz,Mexico

Tropical montane cloud forest is rapidly disappearing and our knowledge of how to restore this system is limited. In a cloud forest of central Veracruz, Mexico, we studied seedling survival, growth, and causes of mortality (microenvironment and herbivory) of three native tree species, Fagus grandifolia, Quercus germana, and Q. xalapensis, transplanted into abandoned pastures (<1 year old) and secondary forests (9–17 years old). Microenvironment differed between the two habitats, temperature and photosynthetically active radiation were higher, and humidity was lower in the abandoned pastures than in the secondary forests. Seedling survival was greater in secondary forests than in pastures: F. grandifolia, 94 and 64%; Q. germana, 88 and 68%; and Q. xalapensis, 61 and 57%, respectively. The cause of mortality differed between habitats, with gophers (24.2% mortality) and mice (4.8%) killing the most seedlings in pastures, and damping‐off (16%) was the most important cause in secondary forests. The relative growth rate in height and basal area was significantly higher in abandoned pastures than in secondary forests; Q. xalapensis had the highest growth rate, followed by Q. germana and F. grandifolia. The environmental conditions in this mountainous cloud forest region seem less stressful to planted seedlings than the conditions of other lowland systems, as frequent clouds favor their establishment even in open sites. We conclude that Fagaceae species can successfully establish in abandoned pastures in mesic environments. Thus, the species studied can be used to speed cloud forest regeneration in the same area at different successional stages.     

Carabids of differently aged reforested pinewoods and a natural pine forest in a historically modified landscape

We studied the responses of carabid beetles to Pinus sylvestris ageing in four plantations aged 2–3, 10–12, 40–45 and 80 years, and one mature natural pine forest – in NW Spain. In 2003, a total of 16,866 carabid individuals (50 species) were collected using pitfall traps. Overall carabid abundance and species richness differed significantly among the five age classes with the highest values occurring in the youngest age class. The carabid assemblages of the initial stages of the ageing sequence differed considerably from the later stages that were relatively similar to each other – a consequence of differences in species dominance at specific age classes. Yet, the carabid assemblage of the 80-year-old stage did not approach that of the natural pine forest, but, unexpectedly, the 40–45-year-old age class did. Canopy cover and soil pH were the main environmental variables that affected the carabid distribution. We also detected species-level responses to the ageing process, with open habitat species more abundantly collected at the youngest stages and forest specialists at the older stages. We conclude that carabid beetles responded predictably to the pine plantation ageing process, and that although pine forests in NW Spain do not seem to provide habitat for unique species, they act as secondary habitats for forest specialist species.     

Forest Regeneration in a Chronosequence of Tropical Abandoned Pastures: Implications for Restoration Ecology

During the mid‐1900s, most of the island of Puerto Rico was deforested, but a shift in the economy from agriculture to small industry beginning in the 1950s resulted in the abandonment of agricultural lands and recovery of secondary forest. This unique history provides an excellent opportunity to study secondary forest succession and suggest strategies for tropical forest restoration. To determine the pattern of secondary succession, we describe the woody vegetation in 71 abandoned pastures and forest sites in four regions of Puerto Rico. The density, basal area, aboveground biomass, and species richness of the secondary forest sites were similar to those of the old growth forest sites (>80 yr) after approximately 40 years. The dominant species that colonized recently abandoned pastures occurred over a broad elevational range and are widespread in the neotropics. The species richness of Puerto Rican secondary forests recovered rapidly, but the species composition was quite different in comparison with old growth forest sites, suggesting that enrichment planting will be necessary to restore the original composition. Exotic species were some of the most abundant species in the secondary forest, but their long‐term impact depended on life history characteristics of each species. These data demonstrate that one restoration strategy for tropical forest in abandoned pastures is simply to protect the areas from fire, and allow natural regeneration to produce secondary forest. This strategy will be most effective if remnant forest (i.e., seed sources) still exist in the landscape and soils have not been highly degraded. Patterns of forest recovery also suggest strategies for accelerating natural recovery by planting a suite of generalist species that are common in recently abandoned pastures in Puerto Rico and throughout much of the neotropics.     

Decline of rare and specialist species across multiple taxonomic groups after grassland intensification and abandonment

Traditionally managed mountain grasslands are declining as a result of abandonment or intensification of management. Based on a common chronosequence approach we investigated species compositions of 16 taxonomic groups on traditionally managed dry pastures, fertilized and irrigated hay meadows, and abandoned grasslands (larch forests). We included faunal above- and below-ground biodiversity as well as species traits (mainly rarity and habitat specificity) in our analyses. The larch forests showed the highest species number (345 species), with slightly less species in pastures (290 species) and much less in hay meadows (163 species). The proportion of rare species was highest in the pastures and lowest in hay meadows. Similar patterns were found for specialist species, i.e. species with a high habitat specificity. After abandonment, larch forests harbor a higher number of pasture species than hay meadows. These overall trends were mainly supported by spiders and vascular plants. Lichens, bryophytes and carabid beetles showed partly contrasting trends. These findings stress the importance to include a wide range of taxonomic groups in conservation studies. All in all, both abandonment and intensification had similar negative impacts on biodiversity in our study, underlining the high conservation value of Inner-Alpine dry pastures.     

Beetle species richness along the forest productivity gradient in northern Finland

The occurrence and habitat associations of the majority of invertebrate groups in boreal forests are poorly known, even though these groups represent perhaps over 99% of the animal species diversity in the forests. We studied the beetle (Coleoptera) fauna of four forest site types in northern Finland: in spruce mires, herb rich, mesic and sub-xeric forests. We sampled beetles in 32 study sites with five window and five pitfall traps in each. We describe the species abundance and diversity patterns within and among forest types and relate these patterns to structural components of the forests. The volume of decaying wood varied from 14 to 93 m³ ha⁻¹ among sampling sites. The total beetle catch consisted of 100 333 individuals and 435 species. The beetle species richness did not vary according to site fertility but the number of specimens increased with increasing fertility in heath forest sites. The richness of beetle species correlated only weakly with any of the stand structure characteristics at the stand level. Nevertheless, the detrended correspondence analysis (DCA) indicated that different beetle assemblages are characteristic of different forest types. The high level of beta-diversity in beetles among forest types indicates that focusing exclusively on, for example, key-biotopes (presumed biodiversity hotspots) when selecting areas to be set aside would result in a situation where a large proportion of species, even of the rare and threatened ones, is not included in this network of protected areas. This suggests that the complementary set of different forest types may be the best general strategy to maintain the overall beetle species diversity in boreal forests.     

Early Successional Patterns and Potential Facilitation of Woody Plant Colonization by Rotting Logs in Premontane Costa Rican Pastures

We examined the size, species, location (x and y coordinates), and microsite inhabited by colonizing trees and shrubs in five abandoned pastures in southern Costa Rica. All woody stems greater than 1 m tall in the pastures were measured and mapped, from the overhanging forest edge to 50 m into the abandoned pasture. Species composition of colonists differed substantially among pastures: Croton draco (Euphorbiaceae) dominated one site, two species of Miconia (Melastomataceae) another site, and Verbesina tapentiensis (Asteraceae) a third site. Site 4 had the highest cover of rotting logs (11%), and a four‐fold greater density of colonizing woody plants than the site with the next highest colonist density. For all species pooled, and for several individual taxa, density was positively correlated across sites with abundance of log microsites. Four of the six most common woody species in site 4 occurred on logs significantly more often than expected had they been randomly distributed relative to logs. Site 5 had less abundance of logs, but the common Miconia species was again significantly more likely to be found on log microsites. These results strongly suggest that rotting wood microsites facilitate establishment of bird‐dispersed pioneer trees, which in turn could foster regrowth of other forest species.     

Red spruce forest regeneration dynamics across a gradient from Acadian forest to old field in Greenwich,Prince Edward Island National Park,Canada

Red spruce forests have declined considerably throughout their range in the past decades. As agricultural fields are abandoned and land becomes available for reforestation, the possibility arises for red spruce forests to expand onto them. This study addresses the potential for red spruce forests to expand onto adjacent old fields in Greenwich, Prince Edward Island National Park, Canada. We examined red spruce distribution and abundance, plant species diversity and changes in community composition along a gradient from the interior of red spruce forests out towards the centre of adjacent old fields. Examining the patterns of red spruce distribution and abundance revealed that, where cultivation and logging have been abandoned recently in the fields and forests, regeneration is limited to the forest stands, but in the sites with older fields and forests, regeneration extends into and is more vigorous in the fields. Although species diversity varied from forest to field only for the tree and shrub layers, important changes occurred in the ground species composition. There is no evidence yet that the herbaceous species present in the forest stands will colonise the old fields. The results suggest that both environmental differences among sites and length of time since the fields were abandoned explain red spruce regeneration patterns. In order to more accurately assess the potential for red spruce regeneration in old fields, long-term monitoring of the production, dispersal and viability of red spruce seeds from adjacent forests and of the constraints to seedling establishment and survival in old fields will be needed.     

Forest regeneration in abandoned coffee plantations and pastures in the Cordillera Central of Puerto Rico

Forest structure and species composition were described in abandonedshade and sun coffee plantations and abandoned pastures in Puerto Rico. Foreststructural characteristics were similar to older forest sites afterapproximately 30 yr of recovery. The historical presence of shadecoffee plantations as the dominant agricultural activity in the region hasresulted in the homogenization of secondary forest composition. The continuousdominance of Coffea arabica and species used for shade inabandoned shade coffee contributed to a slower rate of species compositionchange in comparison to abandoned pastures. Abandoned pastures were initiallycolonized by a group of light demanding and/or wind dispersed species and thenby shade tolerant species characteristic of abandoned shade coffee plantations,suggesting that the secondary forests of abandoned shade coffee plantation arethe major source of species in this landscape. The presence of a few isolatedbig trees in sun coffee plantations appeared to facilitate colonization ofwoodyspecies similar in composition to abandoned shade coffee plantations. In amultivariate analysis, time since abandonment and elevation were the variablesthat explained the majority of variability in species composition among sites.However, a few native species (e.g. Guarea guidonia,Casearia sylvestris, Ocotealeucoxylon) were common regardless of land use history or elevation.In contrast, important old forest species (e.g. Sloaneaberteriana, Dacryodes excelsa,Manilkara bidentata) were rare or absent from most of thesecondary forest stands suggesting the need to reintroduce these species. Landmanagement and conservation efforts can be improved by incorporating theeffectsof land use history on secondary forest dynamics.     

The effects of vegetation types and microhabitats on carabid beetle community composition in cool temperate Japan

The effects of vegetation types and environmental factors on carabid beetle (Coleoptera: Carabidae) communities were studied. Carabid beetles were collected using pitfall traps (total 2844 trapping days) and seven microenvironmental factors were measured in four vegetation types: grassland, natural evergreen coniferous forest (Pinus densiflora), deciduous broad-leaved natural forest (Quercus crispula, Betula platyphylla, Alnus japonica, or Fagus crenata), and deciduous coniferous plantation (Larix kaempferi) in cool temperate Japan. These four vegetation types provided a novel comparison between natural forests and plantations because the vast majority of related studies have investigated only deciduous broad-leaved natural forests and evergreen coniferous plantations. PERMANOVA indicated that vegetation types affected carabid community composition. Ordination plots showed that community composition differed greatly between grassland and forest vegetation types, but that community composition in the plantation forest overlapped with that of natural forest types. Characteristics differentiating the grassland included a high proportion of winged species and a low mean carabid body weight. Among the examined environmental factors, litter depth, soil water content, and depth of the soil A-horizon had large effects on carabid communities. These results suggest that the effect of afforestation on carabid communities in cool temperate Japan might be insignificant compared with the effects of cover types (deciduous vs. evergreen) and microenvironmental factors.     

Invertebrate conservation at the interface between the grassland matrix and natural Afromontane forest fragments

Diversity patterns of amphipods, carabid beetles and ants were investigated in five naturally-fragmented Afromontane forest remnants, and in the surrounding grassland matrix. Forests were architecturally similar. In contrast, grasslands surrounding these forests are subject to great differences in anthropogenic impacts. Consequently, transition from forest to grassland ranged from being abrupt (heavy disturbance) to gradual (little disturbance). Significantly different mean numbers of carabid individuals and species were captured between sites and multivariate analyses showed clear separation in carabid assemblage-structure with level of disturbance. Carabids were, furthermore, significantly more diverse in forests, compared to grasslands. Ants, however, were equally species rich between sites but were significantly more abundant and species rich in grasslands than forests. Amphipods, represented here by a single species, Talistroides africana, was significantly less abundant at highly disturbed sites and significantly more abundant in forests than grasslands. Results support the hypothesis that the dynamics of remnants are influenced by their surrounding landscape. Here, the dynamics of amphipods and carabids (predominantly forest taxa) were influenced by different disturbance regimes in grasslands surrounding these forests. Epigaeic ants, a predominantly grassland taxon here, also showed significant differences in assemblage-composition between sites with varying disturbance. Conserving Afromontane grasslands should be of prime concern because this will include the protection of forest/grassland ecotones and forest remnants.     

Change in land use alters the diversity and composition of Bradyrhizobium communities and led to the introduction of Rhizobium etli into the tropical rain forest of Los Tuxtlas (Mexico)

Nitrogen-fixing bacteria of the Bradyrhizobium genus are major symbionts of legume plants in American tropical forests, but little is known about the effects of deforestation and change in land use on their diversity and community structure. Forest clearing is followed by cropping of bean (Phaseolus vulgaris) and maize as intercropped plants in Los Tuxtlas tropical forest of Mexico. The identity of bean-nodulating rhizobia in this area is not known. Using promiscuous trap plants, bradyrhizobia were isolated from soil samples collected in Los Tuxtlas undisturbed forest, and in areas where forest was cleared and land was used as crop fields or as pastures, or where secondary forests were established. Rhizobia were also trapped by using bean plants. Bradyrhizobium strains were classified into genospecies by dnaK sequence analysis supported by recA, glnII and 16S-23S rDNA IGS loci analyses. A total of 29 genospecies were identified, 24 of which did not correspond to any described taxa. A reduction in Bradyrhizobium diversity was observed when forest was turned to crop fields or pastures. Diversity seemed to recover to primary forest levels in secondary forests that derived from abandoned crop fields or pastures. The shifts in diversity were not related to soil characteristics but seemingly to the density of nodulating legumes present at each land use system (LUS). Bradyrhizobium community composition in soils was dependent on land use; however, similarities were observed between crop fields and pastures but not among forest and secondary forest. Most Bradyrhizobium genospecies present in forest were not recovered or become rare in the other LUS. Rhizobium etli was found as the dominant bean-nodulating rhizobia present in crop fields and pastures, and evidence was found that this species was introduced in Los Tuxtlas forest.     

Leaf litter and the small-scale distribution of carabid beetles (Coleoptera, Carabidae) in the boreal forest

Management practices favoring conifers at the expense of deciduous tree species, and the eradication of deciduous trees, especially aspen Populus tremula , from managed forests have resulted in population declines in several species in Fennoscandia. In addition to species depending on decaying wood of deciduous trees, earlier evidence suggests that leaf litter, especially that of aspen, is favored by many carabid species. We ran a four-year experiment in order to compare carabid assemblages of unchanged forest floor with artificially created leaf-litter plots in central Finland. A total of 18 plots (5 m in diameter) were established in three forest stands without aspen a few kilometers apart. Each stand had 3 litter plots (litter added) and 3 control plots, Pre-treatment samples were compared with those collected alter litter addition.
The litter addition affected the carabid-assemblage structure by increasing the catches of some species and decreasing the catch of one species. The number of carabid species was similar in control and litter plots. The litter effect was smaller than variation among forest stands and year-lo-year fluctuations. There was a strong temporal constancy among the plots: 'rich' plots remained 'rich' from year to year and similarly, 'poor' plots remained 'poor'.
The significant influence of leaf litter on carabid abundance can be attributable to both abiotic factors (microenvironmental conditions, especially humidity and temperature), and biotic ones (changes in niche structure, improved food supply). Leal litter seems to have an effect on carabid distribution patterns, and deciduous trees scattered among conifers are likely to be of importance on carabid fauna in boreal forests.     

Rapid evaluation of ant diversity in land use systems in southern Bahia, Brazil

We aimed to compare the soil ant diversity in different land use systems from Atlantic Forest area, in Southern Bahia state, Brazil. The ants were sampled in 16 sites: two primary forest sites (un-logged forest); three young secondary forests (<8 years old); three intermediate secondary forests (8-20 years old); three old secondary forests (>20 years old); three Eucalyptus grandis plantations (3-7 years old), and two introduced pastures. Each site was sampled in three sampling points 15 m apart, and distant over 50 m from the site edge. In each sampling point we gathered the litter from a 1 m2 and extracted the ants with Winkler extractors during 48h. We found 103 ant species from 29 genera and eight subfamilies. The five richest genera were Pheidole (19 species), Solenopsis (8), Apterostigma (10), Hypoponera (7) e Paratrechina (5). The highest ant richness density was found in the primary forest (7.4 species/sample; S = 37; n = 5); followed by the old secondary forest (5.33 species/sample; S = 48; n = 9); young secondary forest (5.25 species/sample; S = 42, n = 8); eucalyptus plantation (4.22 species/sample; S = 38, n = 9), intermediate secondary forest (3.5 species/sample; S = 35, n = 10, and introduced pasture (2.67 species/sample; S = 16, n = 6). The ecosystems with higher structural complexity showed the highest ant richness density by sample. Therefore, in the Atlantic Forest region, the eucalyptus plantation is a better alternative of land use to conserve the ant biodiversity than pastures, and quite similar to native secondary forests in ant community characteristics.     

Convergence in Arthropod Assemblages with Various Restoration Approaches for Canadian Deciduous Forests

Silvicultural practices are traditionally aimed at increasing forest profits; however, recent approaches to forest conservation have broadened to include nature-based silviculture for regenerating forests. In southern Ontario (Canada), originally dominated by deciduous forests, conifer plantations were established on abandoned agricultural sites. Currently, there is an increasing interest to convert these conifer stands to a state that mimics the original deciduous forest. We investigated arthropod abundance, species richness of carabid beetles, and abundance of arthropod assemblages (trophic and prey groups) under five silvicultural treatments conducted to regenerate deciduous forests (the natural forest type) from the old conifer plantations. The treatments included: (1) uniform canopy removal; (2) uniform canopy removal and understory removal; (3) group canopy removal; (4) group canopy removal and understory removal; and (5) untreated control plots (relatively pure red pine). Insects were sampled annually using sweepnets and pitfall traps. Results revealed treatment effects on the abundance of Coleoptera, Heteroptera, herbivores, and small arthropods (<3 mm) caught in sweepnet samples, where plots subjected to group shelterwood removal and understory removal supported higher abundances than the control plots. There was no treatment effect on the abundance of other arthropod groups or on the species richness and abundance of carabid beetles. The silvicultural treatments used to encourage natural regeneration did not seem to affect arthropod food availability for insectivorous vertebrates. Thus, the type of silvicultural strategy used to convert pine plantations to a stage that mimics the natural deciduous forests had little overall impact on arthropods.     

Forest edge contrasts have a predictable effect on the spatial distribution of carabid beetles in urban forests

Fragmented urban forest remnants are characterised by sharp edges and are bordered by various land-use types, which may have a considerable effect on the fauna and flora at forest edges, and into forest interiors. To investigate the effects of differentially contrasting edges (low vs. intermediate vs. high) on carabid beetle assemblages in urban boreal forests, we placed pitfall traps along a gradient from 6?m into three matrix types (secondary forest vs. grassland vs. asphalt) up to 60?m into urban forest patches in the cities of Vantaa and Helsinki, southern Finland. Individual species and carabid beetle assemblages were strongly affected by edge contrasts and distance from the forest edge. The strongest effect on individual species was caused by high contrasting edges: generalist and open-habitat species were favoured or not affected while forest specialists were affected negatively. Effects of the abundances of potential prey and competitors on the carabid beetles were also evaluated. Forest and moisture-associated carabid species were negatively to neutrally associated with springtail abundances while generalist and open habitat, and dryness associated species were more positively related to springtail abundances (a potential food source). In terms of potential competitors, forest and moisture-associated carabid species were negatively and/or neutrally affected by ant and wood ant numbers, while generalist and open-habitat species were neutrally to positively associated with these taxa. It appears that carabid beetle habitat associations are more important in the responses of these beetles across edges of different contrast than are the prey and competitor numbers collected there. We recommend the creation of “soft” or low-contrast urban edges if the aim of urban management is to protect forest carabids in cities.     

Impact of rubber plantation on carabid beetle communities and species distribution in a changing tropical landscape (southern Yunnan, China)

Carabid beetles (Coleoptera: Carabidae) have widely been used to assess biodiversity values of different habitats in cultivated landscapes, but rarely in the humid tropics. This study aimed to investigate effects of land use change on the carabid assemblages in a tributary valley of the Mekong River in tropical southern Yunnan, China. The study area includes habitats of traditional land use systems (rice production and shifting cultivation successions) and was dominated by natural forests until about 30?years ago. Since then, large areas of forest have been, and still are, successively transformed into commercial rubber monoculture plantations. In total, 102 species of Carabidae (including Cicindelinae) were recorded from 13 sites over different seasons, using pitfall traps, Malaise traps and aerial collectors in trees. Cluster analysis and indicator species analysis showed that three types of habitat (rice field fallows, early natural successions and natural forest) possess a degree of uniqueness in species composition. Non-metric multidimensional scaling revealed that the environmental factors explaining 80% of the total variation in carabid assemblage composition are the degree of vegetational openness of a habitat and its plant species diversity. Rice field fallows had significantly higher numbers of species and individuals than any other type of habitat and are probably dominated by species originating from other regions. Carabid assemblages of young rubber plantations (5 and 8?years) were quantitatively similar to those of forests, but without species of significant indicator value. With increasing plantation age (20 and 40?years), the number of carabid species decreased. Increasing age and a further spatial expansion of rubber plantations at the expense of forest areas will have negative impacts on the native forest carabid assemblages with strongest effects on forest specialists and rare species.