Promoting Pollinating Insects in Intensive Agricultural Matrices: Field-Scale Experimental Manipulation of Hay-Meadow Mowing Regimes and Its Effects on Bees

Bees are a key component of biodiversity as they ensure a crucial ecosystem service: pollination. This ecosystem service is nowadays threatened, because bees suffer from agricultural intensification. Yet, bees rarely benefit from the measures established to promote biodiversity in farmland, such as agri-environment schemes (AES). We experimentally tested if the spatio-temporal modification of mowing regimes within extensively managed hay meadows, a widespread AES, can promote bees. We applied a randomized block design, replicated 12 times across the Swiss lowlands, that consisted of three different mowing treatments: 1) first cut not before 15 June (conventional regime for meadows within Swiss AES); 2) first cut not before 15 June, as treatment 1 but with 15% of area left uncut serving as a refuge; 3) first cut not before 15 July. Bees were collected with pan traps, twice during the vegetation season (before and after mowing). Wild bee abundance and species richness significantly increased in meadows where uncut refuges were left, in comparison to meadows without refuges: there was both an immediate (within year) and cumulative (from one year to the following) positive effect of the uncut refuge treatment. An immediate positive effect of delayed mowing was also evidenced in both wild bees and honey bees. Conventional AES could easily accommodate such a simple management prescription that promotes farmland biodiversity and is likely to enhance pollination services.

Species interactions and random dispersal rather than habitat filtering drive community assembly during early plant succession

Theory on plant succession predicts a temporal increase in the complexity of spatial community structure and of competitive interactions: initially random occurrences of early colonising species shift towards spatially and competitively structured plant associations in later successional stages. Here we use long-term data on early plant succession in a German post mining area to disentangle the importance of random colonisation, habitat filtering, and competition on the temporal and spatial development of plant community structure. We used species co-occurrence analysis and a recently developed method for assessing competitive strength and hierarchies (transitive versus intransitive competitive orders) in multispecies communities. We found that species turnover decreased through time within interaction neighbourhoods, but increased through time outside interaction neighbourhoods. Successional change did not lead to modular community structure. After accounting for species richness effects, the strength of competitive interactions and the proportion of transitive competitive hierarchies increased through time. Although effects of habitat filtering were weak, random colonization and subsequent competitive interactions had strong effects on community structure. Because competitive strength and transitivity were poorly correlated with soil characteristics, there was little evidence for context dependent competitive strength associated with intransitive competitive hierarchies.

Plant species decline due to abandonment of meadows cannot easily be reversed by mowing. A case study from the southern Alps

Abstract. We resumed mowing in two plots of ca. 100 m2 in an abandoned meadow dominated by Brachypodium pinnatum on the slope of Monte Generoso (Switzerland). We monitored species composition and hay yield using point quadrats and biomass samples. Species frequencies changed little during 10 yr (1988–1997) while hay yields showed large fluctuations according to mean relative humidity in April-June. We performed a seed-addition experiment to test whether the establishment of meadow species is limited by lack of diaspores or favourable microsites for germination and recruitment from the seed bank. We sowed ca. 12 000 seeds of 12 species originating from a nearby meadow individually in plots of a 4 × 6 unbalanced Latin square with four treatments, burning, mowing, mowing and removal of a layer of decayed organic matter, and a control. We monitored the fate of seedling individuals for 24 months. Seedlings of all species were established and survived for 12 months, 10 species survived during at least 24 months, some reached a reproductive stage. Species responded to different qualities of microsites provided by the different treatments thus required different regeneration niches. Spontaneous long-distance immigration was insignificant. We conclude that the former species composition of abandoned meadows cannot easily be restored by mowing alone because many plant species of meadows do not have persistent seed banks and immigration over distances of more than 25 m and successful establishment is very unlikely.

Genetic diversity and differentiation follow secondary succession in a multi-species study on woody plants from subtropical China

Aims: Species diversity and genetic diversity may be affected in parallel by similar environmental drivers. However, genetic diversity may also be affected independently by habitat characteristics. We aim at disentangling relationships between genetic diversity, species diversity and habitat characteristics of woody species in subtropical forest. Methods: We studied 11 dominant tree and shrub species in 27 plots in Gutianshan, China, and assessed their genetic diversity (Ar) and population differentiation (F’ST) with microsatellite markers. We tested if Ar and population specific F’ST were correlated to local species diversity and plot characteristics. Multi-model inference and model averaging were used to determine the relative importance of each predictor. Additionally we tested for isolation-by-distance and isolation-by-elevation by regressing pairwise F’ST against pairwise spatial and elevational distances. Important findings: Genetic diversity was not related to species diversity for any of the study species. Thus, our results do not support joint effects of habitat characteristics on these two levels of biodiversity. Instead, genetic diversity in two understory shrubs, Rhododendron simsii and Vaccinium carlesii, was affected by plot age with decreasing genetic diversity in successionally older plots. Population differentiation increased with plot age in Rhododendron simsii and Lithocarpus glaber. This shows that succession can reduce genetic diversity within, and increase genetic diversity between populations. Furthermore, we found four cases of isolation-by-distance and two cases of isolation-by-elevation. The former indicates inefficient pollen and seed dispersal by animals whereas the latter might be due to phenological asynchronies. These patterns indicate that succession can affect genetic diversity without parallel effects on species diversity and that gene flow in a continuous subtropical forest can be restricted even at a local scale.

Sporocarp succession of soil-inhabiting macrofungi in an autochthonous subalpine Norway spruce forest of Switzerland

Sporocarps of macrofungi have been recorded in two neighbouring pure stands of Norway spruce (Picea abies) of different age due to a wind-throw in the subalpine zone of the Alps. The still open young stand of 30 years with trees up to 6 m displayed 80 species, the mature closed forest stand 90 species. Species richness of mycorrhizal fungi is higher in the mature stand than in the younger one, however, with an almost doubled sporocarp production in the latter one. The opposite is found with saprotrophic fungi. Several fungi appeared only in one forest type confirming the concept of early stage versus late stage fungi. Wind-throws as irregular events in subalpine forests, create gaps and add considerably to the species diversity of macrofungi.

Incumbents’ Attitude Toward Intra-Family Succession: An Investigation of its Antecedents

Incumbents’ attitude toward intrafamily succession (IFS) is a critical individual-level determinant of family firms’ IFS intention, which is, in turn, an important component of family business essence. Knowledge about its antecedents, however, is fragmented and very limited. Drawing on the theory of planned behavior and general attitude literature, hypotheses about the situational and individual antecedents of family firm incumbents’ attitude toward IFS were developed and tested with a sample of 274 Italian family firm incumbents. Results show that incumbents’ attitude toward IFS is indeed influenced by both situational and individual antecedents as well as by their interactions.

Family Firm Incumbent’s Attitude toward Intra-family Succession: Antecedents and Effects on Intentions

Research shows that intention for intra-family succession is an important determinant of family firm behavior. To provide a systematic analysis of the antecedents of such intention, we use the theory of planned behavior to model the incumbent leader’s attitude toward intra-family succession because that particular attitude is idiosyncratic to family firms. Empirical tests using a sample of 271 Italian incumbent leaders of family firms show that, as predicted by planned behavior theory, attitude and self-efficacy are significant predictors of intention. They show further that attitude is affected by the number of children, emotional attachment, and need for control.

Succession Intentions Across the Globe: The Role of Institutional Factors

While succession intentions have received increasing scholarly attention in recent years, there is a lack of knowledge about country-level antecedents and differences. Our paper aims to close this gap by investigating succession intentions of 6,360 students with family business background from 26 countries. More specifically, we blend theory of planned behavior with institutional theory and find that institutional variables such as individualism, uncertainty avoidance, and the level of corruption explain the formation of succession intentions over and above traditional theory of planned behavior elements. In addition, we reveal a U-shaped relationship between a nation's level of economic development and the strength of succession intentions. This indicates the existence of two types of succession intentions: necessity and opportunity succession. These findings add valuable insights to literature on family businesses, succession, theory of planned behavior, and practice.