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a b s t r a c tStatistically-designed inventories and biodiversity monitoring programs are gaining relevance for biological conservation and natural resources management. Mandated periodic surveys provide unique opportunities to identify and satisfy natural resources management information needs. However, this is not an end in itself but rather is the beginning of a process that should lead to sound decision-making in biodiversity conservation. Forest inventories are currently evolving towards multipurpose resource surveys and are broadening their scope in several directions: (i) expansion of the target population to include non-traditional attributes such as trees outside the forest and urban forests; (ii) forest carbon pools and carbon sequestration estimation; (iii) assessment of forest health; and (iv) inclusion of additional variables such as biodiversity attributes that are not directly related to timber assessment and wood harvesting.There is an on-going debate regarding the role of forest inventories in biodiversity assessment and monitoring. This paper presents a review on the topic that aims at providing updated knowledge on the current contribution of forest inventories to the assessment and monitoring of forest biodiversity conditions on a large scale. Specific objectives are fourfold: (i) to highlight the types of forest biodiversity indicators that can be estimated from data collected in the framework of standard forest inventories and the implications of different sampling methods on the estimation of the indicators; (ii) to outline current possibilities for harmonized estimation of biodiversity indicators in Europe from National Forest Inventory data; (iii) to show the added value for forest biodiversity monitoring of framing biodiversity indicators into ecologically meaningful forest type units; and (iv) to examine the potential of forest inventory sample data for estimating landscape biodiversity metrics.

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31Theory on plant succession predicts a temporal increase in the complexity of spatial 32 community structure and of competitive interactions: initially random occurrences of early 33 colonising species shift towards spatially and competitively structured plant associations in 34 late successional stages. Here we use long-term data on early plant succession in a German 35 post mining area to disentangle the importance of random colonisation, habitat filtering, and 36 competition on the temporal and spatial development of plant community structure. We used 37 species co-occurrence analysis and a recently developed method for assessing competitive 38 strength and hierarchies (transitive versus intransitive competitive orders) in multispecies 39 communities. We found that species turnover decreased through time within interaction 40 neighbourhoods, but increased through time outside interaction neighbourhoods. Successional 41 change did not lead to modular community structure. After accounting for species richness 42 effects, the strength of competitive interactions and the proportion of transitive competitive 43 hierarchies increased through time. Although effects of habitat filtering were weak, random 44 colonization and subsequent competitive interactions had strong effects on community 45 structure. Because competitive strength and transitivity were poorly correlated with soil 46 characteristics, there was little evidence for context dependent competitive strength associated 47 with intransitive competitive hierarchies. 48 49Running title: Plant community structure in early plant succession 50 51

Successional phases describe changes in ecological communities that proceed in steps rather than continuously. Despite their importance for the understanding of ecosystem development, there still exists no reliable definition of phases and no quantitative measure of phase transitions. In order to obtain these data, we investigated primary succession in an artificial catchment (6 ha) in eastern Germany over a period of 6 years. The data set consists of records of plant species and their cover values, and initial substrate properties, both from plots in a regular grid (20 m × 20 m) suitable for spatial data analysis. Community assembly was studied by analyses of species co-occurrence and nestedness. Additionally, we correlated lognormal and log series distributions of species abundance to each community. We here introduce a new general method for detection of successional phases based on the degree of transient spatial homogeneity in the study system. Spatially coherent vegetation patterns revealed nonoverlapping partitions within this sequence of primary succession and were characterized as two distinct ecological phases. Patterns of species co-occurrence were increasingly less random, and hence the importance of demographic stochasticity and neutral community assembly decreased during the study period. Our findings highlight the spatial dimension of successional phases and quantify the degree of change between these steps. They are an element for advancing a more reliable terminology of ecological successions.