Exploring spatiotemporal patterns in early stages of primary succession on former lignite mining sites

Abstract

Questions: 1. Does random colonization predominate in early stages of primary succession? 2. Do pioneer species facilitate the establishment of later arriving species? 3. Does an initially random distribution change to an aggregated pattern with ongoing succession? Location: Lignite mining region of Lower Lusatia, eastern Germany. Methods: Individual plants were mapped along a 2 m × 28 m transect during three successive years and classified into two groups (1) the pioneer Corynephorus canescens and (2)‘all other species’. Using the pair‐correlation function, univariate point pattern analysis was carried out by applying a heterogeneous Poisson process as null model. Bivariate analysis and a toroidal shift null model were applied to test for independence between the spatial patterns of the two groups separately for each year, as well by exploring spatiotemporal patterns from different years. Results: In the first year Corynephorus and ‘all other species’ showed an aggregated pattern on a spatial scale > 40 cm and in the second and third years a significant attraction for distances between 4 and 12 cm, with an increasing radius in the third year. The analyses of interspecific spatiotemporal dynamics revealed a change from independence to attraction between distances of 4 cm and 16 cm when using Corynephorus as focal species. However, applying ‘all other species’ as focal points results in a significant attraction at distances up to 60 cm in the first year and a diminishing attraction in the second and third years with distances ≤ 6 cm. Conclusions: Facilitative species‐species interactions are present in early stages of primary succession, resulting mainly from pioneer species acting as physical barriers and their ability to capture diaspores being drifted by secondary dispersal along the substrate surface. However, due to gradual establishment of perennial species and their ability of lateral extension by vegetative dispersal, facilitation may influence spatial pattern formation predominantly on short temporal and fine spatial scales.

Changes in spatial point patterns of pioneer woody plants across a large tropical landslide

“…The aggregated patterns found in subzone El are similar to those observed in other stressful environments such as semi-arid shrublands (Rayburn et al, 2011) and savannas (Schleicher et al, 2011), and high-mountain communities (Fajardo et al, 2008). We also detected an increase in aggregation over the study period, as found by Malkison and Kadmon (2007), and Felinks and Wiegand (2008) in early successional communities. On the contrary, we found that the pattern of new recruited individuals was independent of (subzone El), or showed repulsion to (subzones El and E3), surviving individuals (Fig.…”

“…This has been possible because over the first few years of succession spatial point patterns of pioneer species markedly change (Malkison and Kadmon, 2007;Felinks and Wiegand, 2008), particularly in regions of tropical climate, where this process is rapid . However, the examination of other processes, such as facilitation of juvenile pioneer trees by mature ones (Nishimura and Kohyama, 2002), may require longer time frames or a space-for-time substitution approach (Walker et al, 2010a).…”

“…3 and S2), that is, up to much larger spatial scales than those occupied by the crowns of the shrubs and tree saplings occurring in this subzone. The two dominant species in this subzone, W. wens and I micrantha, which also comprised the highest proportion of established and dead individuals (Table 1), both present erect individuals and therefore do not possess the appropriate architectural characteristics to act as physical barriers (Felinks and Wiegand, 2008). These two species, however, have a high litterfall production and their leaves present high contents of nutrients such as Mn and Cu, which are not very abundant in harsh sites (Valencia-Duarte, 2012;da Trindade and Coelho, 2012).…”

“…These positive interactions lead to aggregated distributions of individuals (Schleicher et al, 2011). In sites subjected to vegetation recovery, aggregated patterns become more evident as a consequence of the greater significance of positive interactions over the first few years of succession (Felinks and Wiegand, 2008). Moreover, facilitation usually generates spatial patterns characterised by a high degree of aggregation, on one hand, among dead individuals and on the other hand, among surviving ones (Malkison and Kadmon, 2007).…”

“…All these processes create positive spatial associations (i.e. attraction) between established and newly recruited individuals (Felinks and Wiegand, 2008). Conversely, in less stressful environments, where competition usually prevails, plant individuals are regularly spaced Moustakas et al, 2008), and these regular patterns become more evident over time (Stoll and Bergius, 2005).…”