Young Successional Stages Research Articles

Diversity in Landscape Management Affects Butterfly Distribution

The aim of the study was to determine the influence of differentiated landscape management on the distribution and abundance of butterfly species. The question was raised with regard to which land use type benefited butterflies, and which affected them, that is: under which management type does biodiversity increase, and under which is it depleted? The spatial and abundance distributions of the examined butterfly species diverged considerably. The observed differences between the abundance distributions may be due to diverse conditions in the small-scale environments or specific food preferences of individual species. The diversified management of the “Krzywda” landscape fosters the abundance of mesophilic and ubiquitous butterfly species, whereas xerotermophilic and hygrophilous species are not fostered. The transects established on the fallow land with harvested biomass as well as that with unharvested biomass and in the forest ecotone showed that the fallows were characterized by the highest abundance of butterflies, and the greatest number of plant species was recorded there. Mown fallow lands with not harvested biomass as well as forested areas fostered polyphagous and monophagous butterfly species. Oligophagous butterfly species were fostered by mown fallow lands with not harvested biomass. Unmown meadows, the ecotone marshland and fallow, as well as unmown fallow lands did not foster butterfly abundance. This most likely means that land management can influence the food base of butterflies, and consequently, their abundance. The stage of succession as well as the homogeneity of the area in terms of vegetation had the strongest filtering effect on the occurrence and distribution of butterflies among the analyzed variables. The number of species as well as their abundance was higher on transects classified as young successional stages on which successional processes were artificially inhibited by mowing and biomass removal. Advanced environmental engineering enables humans to influence species composition in a given ecosystem to achieve a desired result. There is no doubt that human activity will be successful when the needs of individual species in a given environment are accurately understood.

Response of habitat quality to mixed severity disturbance regime in Norway spruce forests

Abstract Natural disturbances change forest habitat quality for many species. As the extent and intensity of natural disturbances may increase under climate change, it is unclear how this increase can affect habitat quality on different spatial scales. To support management tools and policies aiming to prevent habitat loss, we studied how habitat quality develops in the long run depending on the disturbance severity using a space‐for‐time substitution approach. We explored the effects of time since disturbance (0–250 years) and disturbance severity (20%–100% canopy removal) on structure‐based habitat quality indicators in European primary Norway spruce Picea abies forests using 1000 m2 circular plots in hierarchical design (a total of 407 plots in 35 stands). Disturbance history was reconstructed from tree cores. Habitat quality indicators were modelled as a function of the severity of the most severe disturbance and the time since this disturbance. We hypothesised that high within‐stand habitat heterogeneity is formed by different successional stages after disturbances of various intensities. The results showed a U‐shaped response of habitat quality to post‐disturbance habitat succession on the plot scale. The decline deepened with disturbance severity. The U‐shape response occurred in: large tree occurrence, amount of standing and lying deadwood, diversity of understory and understory openness. The spatial diversity in disturbance parameters increased spatial diversity of habitat quality on a stand level as expected. This high within‐stand habitat heterogeneity also decreased with increasing age of the most recent disturbance. This suggests that the absence of young successional stages results in the absence of some important elements for biodiversity, for example sun‐exposed snags. Synthesis and applications. Our results demonstrate that currently intensifying natural disturbance regime can consequently result in a lower habitat heterogeneity. In managed spruce forests after natural disturbances, we recommend at least the partial retention of biological legacies to preserve habitat heterogeneity and to avoid uniform and dense plantations resulting in a greater homogenisation. To emulate the natural disturbances pattern, spruce forests should be managed with a wide range of harvested patches of the size limited by a local natural disturbance regime creating spatial heterogeneity.

Habitat selection of sympatric Siberian Grouse and Hazel Grouse in natural and exploited forests of the lower Amur region

The Siberian Grouse (Falcipennis falcipennis), which is endemic to the “dark-needle” taiga of the Russian Far East, is one of the least studied grouse species in the world. We examined post-breeding habitat selection of Siberian Grouse and contrasted it with that of the better examined Hazel Grouse (Tetrastes bonasia) in two areas near Komsomolsk na Amure, Russia. To infer species-specific preferences, we used field sampling, logistic regression, and AIC model selection, and compared late summer habitats of Siberian Grouse and Hazel Grouse in a mountain- and hilly area in the dark needle taiga. Our study is the first to explain Siberian Grouse habitat relationships with an empirical modelling approach. Results indicate proportions of coniferous/ pioneer trees forest and rejuvenation to be the most important covariates separating Siberian and Hazel Grouse observation sites in forests from both areas. Siberian Grouse tended to select sites with low proportions of pioneer trees and rejuvenation but availability of dwarf shrubs. Bunchberry (Cornus canadensis) appeared to be of high importance for the presence of Siberian Grouse in both regions. Hazel Grouse were common in places dominated by pioneer trees with high canopy cover, and high proportions of grass/herb cover. Hazel Grouse also occurred more often in forest sites with dense vertical layering and rejuvenation. Modern forestry, which results in increasing amounts of forests at younger successional stages, is likely to favour the Hazel Grouse at the expense of the Siberian Grouse.

Lichens in old-growth and managed mountain spruce forests in the Czech Republic: assessment of biodiversity, functional traits and bioindicators

Natural spruce forests are restricted to the highest mountain ranges in the Czech Republic. Spruce is also the commonest tree species in managed forests. Owing to a massive decline of spruce forests in Central Europe, caused by recent climatic fluctuations and disturbances, the lichen diversity and species composition was compared between ten representative natural mountain old-growth forests in the Czech Republic and their counterparts in mature managed forests. The old-growth forests are characterized by a higher species richness, abundance, number of Red-listed species, functional, taxonomic and phylogenetic diversities. Plots with the highest species richness are situated in the Sumava Mountains, an area with a relatively low sulphur deposition in the past. Bioindication analysis searching for lichen indicators supported several species (e.g. Xylographa vitiligo, Chaenotheca sphaerocephala) and genera (e.g. Calicium, Xylographa) with a strong preference for old-growth forests. Analysis of lichen functional traits revealed a higher abundance of species with a vegetative reproduction in managed forests that may be explained by a higher efficiency in colonization by young successional stages. Lichens with stalked apothecia, pigmented ascospores and large ascospores are more frequent in old-growth forests. Our results are briefly discussed in terms of nature conservation, focusing on national refugees of old-growth forest species, biodiversity hot-spots, practical use of indicator species and representative measures for an evaluation of forest quality.

Relationships between vegetation and seed bank in sand pits: Effects of different restoration approaches and successional age

AbstractQuestionsOur study examined the relationships between the seed bank and above‐ground vegetation in spontaneously revegetated and forestry‐reclaimed sand pits. We asked the following questions: (a) What is the composition of the seed bank and above‐ground vegetation? (b) How do they develop over the course of succession within the two different restoration approaches? (c) What is the representation of target and undesirable species in the seed bank and above‐ground vegetation? and (d) Could the seed bank serve as the source for target vegetation restoration?LocationTřeboň Basin, Czech Republic.MethodsThree successional stages and two types of restoration approaches were considered. Bray–Curtis similarity was used for describing the similarity between above‐ground vegetation and the seed bank. Representation of target (dry sandy grassland), desirable (woodland, wetland, mesic grassland) and undesirable (synanthropic) species was assessed.ResultsThe type of restoration approach exhibited stronger effects on the above‐ground vegetation than on the seed bank. The similarity between the seed bank and above‐ground vegetation decreased during succession. Undesirable species formed the dominant species group in the seed bank regardless of successional stage and the type of restoration approach. Target species were represented especially in the above‐ground vegetation of young successional stages. Only half of the number of target species appeared in the seed bank in comparison to above‐ground vegetation and their number further rapidly decreased in older stages of succession.ConclusionsThe result showed that the seed bank of sand pits could be considered as a potential resource mainly for synanthropic species, but it cannot serve as the only source for the eventual restoration of the target vegetation of an open sandy dry grassland after potential clearing, once it becomes overgrown by forest. Consequently, maintaining young successional stages is desirable if we wish to support species typical of dry sandy grassland.

Autogenic ecological succession of a pristine peat bog: focus on factors affecting beetle diversity

ABSTRACTElements of the ancient periglacial flora such as peat bog shrubs provide a paleorefugium in Central Europe for survival of glacial biota and other cold-adapted species during recent climate change. This study provides evidence that diversity of one of the most numerous consumers in peat bogs, beetles, was higher in mid-successional stages characterized by the highest degree of shrub encroachment, compared with early and old stages. The main autogenic factor driving successional changes of herb-shrub layer coleopteran assemblages were shrub cover and bog water level. Younger successional stages contained the highest abundance of herb dwellers (chortobionts) and polyphagous species, whereas middle and old stages contained shrub inhabitants (chamebionts), which are oligophagous species specializing on ericaceous dwarf shrubs. Species richness and abundance of cold-adapted inhabitants of peat bogs (tyrphobiontic and tyrphophilous) increased from young to old successional stages along with increased shrub cover. Herb dwellers and polyphagous species are among the first primary consumers to colonize peat bogs. With changes in late-successional habitats, in particular the invasion of ericaceous dwarf shrubs, chamebiontic and oligophagous species start colonizing.

Dune dynamics safeguard ecosystem services

Intensively used coastal zones often know a history of hard defense structures to prevent erosion and protect infrastructure against floods. The interruption of sand transport between sea, beach and dunes however causes a domination of late successional stages such as dune shrub. With the decline of young, dynamic vegetation types, a change occurs in the provision of ecosystem services. In spite of the growing awareness on the role of dune dynamics to support human well-being and biodiversity, redynamisation of dunes is rarely implemented in coastal zone management. It has been argued in research documents that this may be caused by a failure to make those benefits tangible and specific. This study aims to underpin the added value of dynamic versus fixed dunes. Five different ecosystem services in a case-study in Belgium were quantified based on (compound) indicators and expressed in monetary units. The value of a natural, dynamic dune system covering the entire gradient of dune succession and dominated by young successional stages was compared with the value of a fixed dune system dominated by late successional stages. The results indicate that a dynamic dune complex may create up to ∼50% higher economic benefits, and that the main benefits are on account of recreation and coastal safety maintenance. The results underpin the statement that we can only continue benefitting from the services dunes provide if we accept their mobile nature, but that redynamisation requires a site-specific feasibility analysis.

The implications of succession after fire for the conservation management of moorland invertebrate assemblages

Fire management in protected areas requires an understanding of the consequences of fire regimes. Invertebrates are a key component of biological communities, but studies of fire impacts on diverse invertebrate assemblages over long timeframes are rare. The responses of ground- and foliage-active invertebrate assemblages to fire in buttongrass moorlands were investigated using a space-for-time design. Assemblages in recently burnt moorlands were distinct from those in older moorlands. Contrary to expectations, ground-active invertebrate abundance, but not taxon richness, was greatest in young regrowth (2–3 years since last fire), owing to large populations of Formicidae, Orthoptera, Collembola and Diptera. Foliage-active invertebrate assemblages followed the expected trend with least numbers of invertebrates and taxa in young regrowth. Very few taxa (n = 9) were absent from young successional stages and none were absent from later successional stages. Invertebrate assemblages in moorlands on low productivity soils took approximately twice as long to return to their pre-fire state than assemblages on moderate productivity soils. The shifts in invertebrate composition were associated with shifts in vegetation composition. Vegetation density was found to be a potentially important predictor of invertebrate compositional variation. Fire in buttongrass moorland appears to have a limited impact on ground-active and foliage-active invertebrate assemblages, suggesting that these components of the invertebrate fauna are resilient to fire (i.e. able to return to the pre-fire state). Given that fire impedes successional processes that convert moorlands into rainforest, and eliminate many of the moorland invertebrate species, conservation management of moorlands should involve the acceptance or imposition of fire.

Evaluating Moisture and Geometry Effects on L-Band SAR Classification Performance Over a Tropical Rain Forest Environment

Multitemporal single (HH) and dual-polarization (i.e., HH, HV) L-band spaceborne synthetic aperture radar (SAR) scenes were evaluated under different moisture conditions caused by precipitation prior to data acquisition at varying incidence angles. The changes affecting backscattering intensity, polarimetric decomposition, backscattering mechanism, and land use/land cover classification performance were evaluated. The study area is a shifting-cultivation environment in the eastern Amazon (Brazil). Several data input scenarios were proposed in the classification scheme (i.e., backscattering intensity alone and combined with alpha/entropy decomposition parameters, band ratios, and textural parameters) using a random forest classifier framework. Integration with optical data was also examined. The classification accuracy scores were then compared with accumulated precipitation data. The results showed that the variation in both the vegetation moisture and incidence angle increases the backscattering intensity for pasture, riparian forest and young regenerated forest by at least 1 dB compared with old successional forest stages due to its more uniform vertical structure and the landscape's increased dielectric constant. The overall classification accuracy proved low for each SAR acquisition date compared with the performance of the Landsat data. Based on SAR data, misclassification occurs for the young successional forest stages and increases in scenes with higher moisture conditions. The classification performance benefits from data integration only for one SAR scene acquired in the dry season. The results highlight the importance of selecting proper temporal intervals for the different SAR polarization modes of the forthcoming SAR missions. Further investigations should address both multitemporal at a single frequency as well as multifrequency SAR approaches.

Species-specific and generic biomass equations for seedlings and saplings of European tree species

Biomass equations are a helpful tool to estimate the tree and stand biomass production and standing stock. Such estimations are of great interest for science but also of great importance for global reports on the carbon cycle and the global climate system. Even though there are various collections and generic meta-analyses available with biomass equations for mature trees, reports on biomass equations for juvenile trees (seedlings and saplings) are mainly missing. Against the background of an increasing amount of reforestation and afforestation projects and forests in young successional stages, such equations are required. In this study we have collected data from various studies on the aboveground woody biomass of 19 common tree species growing in Europe. The aim of this paper was to calculate species-specific biomass equations for the aboveground woody biomass of single trees in dependence of root-collar-diameter (RCD), height (H) and the combination of the two (RCD2 H). Next to calculating species-specific biomass equations for the species available in the dataset, we also calculated generic biomass equations for all broadleaved species and all conifer species. The biomass equations should be a contribution to the pool of published biomass equations, whereas the novelty is here that the equations were exclusively derived for young trees.

Object-oriented and pixel-based classification approaches to classify tropical successional stages using airborne high–spatial resolution images

Airborne high–spatial resolution images were evaluated for mapping purposes in a complex Atlantic rainforest environment in southern Brazil. Two study sites, covered predominantly by secondary evergreen rainforest, were surveyed by airborne multispectral high-resolution imagery. These aerophotogrammetric images were acquired at four spectral bands (visible to near-infrared) with spatial resolution of 0.39 m. We evaluated different data input scenarios to suit the object-oriented classification approach. In addition to the four spectral bands, auxiliary products such as band ratios and digital elevation models were considered. Comparisons with traditional pixel-based classifiers were also performed. The results showed that the object-based classification approach yielded a better overall accuracy, ranging from 89% to 91%, than the pixel-based classifications, which ranged from 62% to 63%. The individual classification accuracy of forest-related classes, such as young successional forest stages, benefits the object-based approach. These classes have been reported in the literature as the most difficult to map in tropical environments. The results confirm the potential of object-based classification for mapping procedures and discrimination of successional forest stages and other related land use and land cover classes in complex Atlantic rainforest environments. The methodology is suggested for further SAAPI acquisitions in order to monitor such endangered environment as well as to support National Land and Environmental Management Protocols.

Variable strength of forest stand attributes and weather conditions on the questing activity of Ixodes ricinus ticks over years in managed forests.

Given the ever-increasing human impact through land use and climate change on the environment, we crucially need to achieve a better understanding of those factors that influence the questing activity of ixodid ticks, a major disease-transmitting vector in temperate forests. We investigated variation in the relative questing nymph densities of Ixodes ricinus in differently managed forest types for three years (2008–2010) in SW Germany by drag sampling. We used a hierarchical Bayesian modeling approach to examine the relative effects of habitat and weather and to consider possible nested structures of habitat and climate forces. The questing activity of nymphs was considerably larger in young forest successional stages of thicket compared with pole wood and timber stages. Questing nymph density increased markedly with milder winter temperatures. Generally, the relative strength of the various environmental forces on questing nymph density differed across years. In particular, winter temperature had a negative effect on tick activity across sites in 2008 in contrast to the overall effect of temperature across years. Our results suggest that forest management practices have important impacts on questing nymph density. Variable weather conditions, however, might override the effects of forest management practices on the fluctuations and dynamics of tick populations and activity over years, in particular, the preceding winter temperatures. Therefore, robust predictions and the detection of possible interactions and nested structures of habitat and climate forces can only be quantified through the collection of long-term data. Such data are particularly important with regard to future scenarios of forest management and climate warming.

Ant-diaspore interactions during secondary succession in the Atlantic forest of Brazil

Animal-plant interactions are important for the recovery of diversity and processes in secondary forests, which increasingly dominate the tropical landscape. We used a combination of observational and experimental approaches to study the interactions of ants with diaspores across a successional gradient of forests in Southern Brazil, from August 2007 to April 2008. In addition to diaspore removal rates, we assessed the species richness, diversity and behaviour of ants interacting with diaspores, in three replicated sites of four successional stages of forests. We recorded 22 ant species interacting with diaspores (an estimated 15% of the total species pool in the region). Species richness and diversity did not differ among successional stages but the behaviour of ants towards diaspores changed with the age of secondary forests. In old successional stages the removal of entire diaspores was more common than in young successional stages of forests. Concordantly, diaspore removal rates were lowest in the youngest successional stage of secondary forests and increased with the age of forests. These results indicate that ant-diaspore interactions in secondary forests are disturbed and lower removal rates in secondary forests are likely to constrain the recruitment of plant populations during secondary succession.

Contrasting responses of hoverflies and wild bees to habitat structure and land use change in a tropical landscape (southern Yunnan, SW China)

Abstract The response of insects to monoculture plantations has mainly proceeded at the expense of natural forest areas, and is an outstanding and important issue in ecology and conservation biology, with pollination services declined around the world. In this study, species richness and distribution of hoverfly and wild bee communities were investigated in a changing tropical landscape in southern Yunnan, south‐west China by Malaise traps periodically from 2008 to 2009. Species were recorded from the traditional land use types (natural forest, grassland, shrubland and rice field fallows), and from recently established rubber plantations of different ages. Hoverflies (total 53 species) were most common in young successional stages of vegetation, including rice field fallow and shrubland. Species richness was highest in rice field fallows and lowest in forests and showed a highly significant relationship with the number of forb species and ground vegetation cover. In contrast, the highest richness of wild bees (total 44 species) was recorded from the natural forest sites, which showed a discrete bee community composition compared to the remaining habitat types. There was no significant relationship between the bee species richness and the environmental variables, including the numbers of different plant life forms, coverage of canopy and ground vegetation, successional age of vegetation and land use type. At the landscape scale, open land use systems, including young rubber plantations, are assumed to increase the species richness of hoverflies; however, this might decrease wild bee diversity. The present land use change by rubber cultivation can be expected to have negative impacts on the native wild bee communities.

Colonization of experimentally created gaps along an alpine successional gradient

The colonization of artificially created gaps was analyzed along an alpine successional gradient from pioneer to early, late, and old successional stages. The presence/absence of species and the abundances of seedlings and adults in the gaps were recorded and compared with those of the surrounding areas. We hypothesized that in the older successional stages, the gaps were likely to be colonized by clonal ingrowth of the surrounding species. In the younger stages, we expected to find a high presence of seedlings and adults recruited by seeds. Micro-succession in the gaps occurred at each successional stage, with all life forms among the colonizers. The abundance of seedlings was significantly higher in the gaps compared with the surrounding area. At the early and late successional stages, the surrounding areas provided safe sites for seedling establishment, with the abundance of adults recruited by seeds higher at the gap edges than in the gap centers. We can confirm the first hypothesis of a higher clonal ingrowth in the old successional stage. Clonal ingrowth also occurred in the younger successional stages. Despite the lower species richness in the gaps, a positive correlation was found between gap and surrounding species frequencies, which were the highest in the pioneer and the lowest in the old successional stage. We conclude that gaps are relevant for seedling recruitment along the entire primary succession gradient. New species invasions from greater distances were not observed in the gaps. The dominant species on each site were identified to be successful gap colonizers.

Les indicateurs de la dynamique post-culturale de la végétation des jachères dans la partie savane de la réserve naturelle forestière de Kigwena (Burundi)

Background and aims - A synchronic study has been achieved in fallows distributed in three age classes (0-2 years, 3-5 years and more than five years) in the natural forest reserve of Kigwena (Burundi). The aim was to show that differences in the proportion of plant functional groups could be used as indicators in characterizing the post-cultivation succession stages. Methods - The retained functional groups concerned biological and phytogeographic types, leaf size and diaspores dispersion. Key results - The data analysis gave five floristic associations. The functional group analysis evidences that the young successional stages are often characterized by sclerochorous herbaceous (therophyts) with often anemochorous dispersion, while the aged stages are essentially dominated by sarcochorous phanerophyts with essentially autochorous dispersion. The proportion of species with large distribution decreases with the age of the fallow contrary to species with regional distribution. A progressive increase with the age of species number with large leaves and a reduction of species with small leaves has been observed. Conclusion - The follow-up of the temporal variability of biological traits of species permits to characterize stages of post-cultivation succession. © 2010 National Botanic Garden of Belgium and Royal Botanical Society of Belgium.

Artificial sowing of endangered dry grassland species into disused basalt quarries

Steppe-like dry (semi) natural grasslands are valuable and endangered habitats in central Europe. In the study area (the České středohoří Hills, Czech Republic), they occur in fragments on southern slopes of volcanic hills, often in the vicinity of quarries, which are numerous there. We performed sowing experiments and observed seedling recruitment of six species, typical for the dry grasslands, in 9 basalt quarries located in 3 different climatic regions over 3 yr. The sowing experiments were established in young successional stages, 5–12 yr after quarrying was stopped. The objectives of the experiments were to evaluate: (i) if seedling recruitment and survival of the target species are possible regarding different climatic regions and (ii) what is the influence of weather fluctuations among years on seedling survival. Seedlings of all studied species were able to recruit and survive in the early successional stages at least in some quarries. The species, except one , showed significant differences in recruitment among the climatic regions, with the best recruitment and survival in the driest and warmest region. Seedlings of two species did not recruit in the wettest and coldest region. All species survived in the driest and warmest region, while only one did so in the coldest and wettest region. Different weather conditions in the studied years significantly influenced recruitment of two species. The number of localities (floristic records) of particular species in the regions was the best predictor of species germination and survival. Thus a traditional floristic survey may help to predict success of species in restoration projects. It emerged that artificial sowing can be considered in restoration programs as a way of contributing to restoration of dry grasslands in disused quarries.

Long-term spatio-temporal dynamics and historical continuity of European aspen (Populus tremula L.) stands in the Koli National Park, eastern Finland

Summary Although the European aspen ( Populus tremula L.) is regarded as a keystone species for the biodiversity of northern Europe, its mechanisms of regeneration and persistence under old-growth conditions without large-scale disturbances have remained obscure. The aim of this paper is to describe the long-term dynamics and regeneration of European aspen in the old-growth forests of the Koli National Park, eastern Finland, in order to gain a better understanding of the occurrence of this species under natural forest conditions. The park includes both natural forests and forests that were previously managed. The long-term occurrence of aspen populations was determined on the basis of inventory data available for the years 1910, 1936 and 2004. Aspen is shown to have occurred at least temporarily over 34 per cent of the total forest area (840 ha). In addition, 13 per cent of the forest area continuously supported stands that contained large aspen trees between 1910 and 2004. In areas where no management took place (6.4 per cent of the area), about one-third of all the aspen stands contained large trees and persisted throughout the period. The results show that aspen can maintain long-term occurrence in old-growth forests and that the species is not only transient or confi ned to young successional stages. Areas where aspen regeneration is possible, as deduced from its long-term occurrence should be regarded as highly valuable for biodiversity because they offer long-term habitats for several threatened species that are associated with aspen trees. Recent changes in ecological conditions, however, may affect this in the future. Most notably, the increased population of large mammalian browsers may make aspen regeneration more diffi cult and should be taken into account when restoration and management measures are planned.

Fit for succession – community structure and life strategies of leafhoppers in urban brownfields

Abstract 1. Urban brownfields offer an excellent opportunity to study successional processes. Changes in the frequencies of biological traits during succession are of particular interest. They shed light on the general reasons why species emerge and vanish during the course of succession.2. Leafhopper (Hemiptera: Auchenorrhyncha) occurrence data (3763 species observations) of 194 species were studied. Data was collected on 246 brownfield plots, aged 0–40 years, in two cities in Northern Germany.3. Four categorical traits were studied: host‐plant type, phagy, dormancy, and voltinism. In these traits, two aspects were analysed: (1) changes in trait category frequencies during succession, and (2) distribution of trait categories (i) within the brownfield species pool versus the German species pool and (ii) within species observations.4. Trait categories showed clear successional trends. Young successional stages were related to feeding on herbs, polyphagy, egg overwintering, and two generations per year.5. By analysing combinations of two traits, species could be assigned to four functional groups: species associated with young, intermediate and old sites, and one group indifferent to site age. The pioneer group comprised the least number of species, but the highest number of observations.6. Categories associated with young site age were over‐represented in the brownfield species pool. Moreover, within this already biased species pool, species with pioneer trait categories occurred with higher frequency. For the slow colonisers among leafhoppers, brownfields seem to be habitats that are hard to exploit.

Bat diversity and abundance associated with the degree of secondary succession in a tropical forest mosaic in south‐eastern Mexico

AbstractUnder the hypothesis that bat diversity would be lower in the early stages of secondary succession and that species affected negatively by habitat modification would be more frequent in later successional stages, we evaluated how bats use 12 vegetation stands representing four stages of secondary succession, following disturbance caused by slash‐and‐burn agriculture and selective logging. We compared bat richness, abundance and diversity, and found that none of these variables was different among stages or rainy seasons. However, of the 10 most common bat species, two were significantly more abundant in stands at the early stages of secondary succession, while the opposite was true for three other species. Canopy cover mainly explains these patterns. Rainy season had no effect on the abundance of the common species. The results of this study indicate that although some frugivorous species were very abundant in the younger stands, the majority of the rare species were captured in older stands. The absence of rare and habitat‐specialized species from young successional stages close to primary forest suggests that, for effective bat conservation in landscapes modified by human activity, areas with original vegetation should be maintained to ensure the survivorship of sensitive‐to‐deforestation species.