Over the (range) edge: a 45‐year transplant experiment with the perennial forest herbHyacinthoides non‐scripta

Abstract

Summary1 Most experimental populations of perennial forest herbs have been monitored for only a few years and thus only apply to germination and early seedling survival. Moreover, there is a lack of long-term, quantitative data on the rates of spread of populations. 2 We report the results of a cross-range-edge transplant experiment established in 1960 with the perennial forest herb Hyacinthoides non-scripta. We evaluated determinants of survival/extinction, performance and migration distances and patterns of 27 transplanted populations after a period of 45 growing seasons. 3 Of 27 experimental populations of Hyacinthoides non-scripta implanted in 1960, 11 (41%) were still found in 2005-06. Population survival was independent of soil type and changes in the vegetation layer. In contrast, physical disturbance of the soil and major changes in the tree layer as a result of forest management were the main determinants of population extinction. Current population surface areas ranged from 0.23 to 26.23 m 2 . Plant height, leaf length, number of flowers and seed size were generally lower in the introduced populations than in the source populations. However, densities and proportions of non-flowering adults were higher, especially in the larger populations. This suggests that these populations are still expanding with more but younger, and thus smaller, individuals. 4 Observed migration rates were very low, ranging from 0.006 my − 1 to 0.06 my − 1 . Migration occurred by the establishment of isolated individuals, which were later absorbed by the advancing wave of the main population. The spread projected for the largest population in the next 45 years is only 14 m for the main population front and 42 m for the furthest individual. 5 Our results may be representative of population spread for slow dispersing forest plant species after occasional long-distance dispersal events across a range edge. However, the slow rates of spread indicate that, even if such events occur, it can take a very long time to establish viable population sizes.

Long-term restoration success of re-sprouter understorey species is facilitated by protection from herbivory and a reduction in competition

“…While numerous studies have monitored plant survival following experimental plantings (e.g., Petersen and Philipp 2001;Mottl et al 2006), the factors affecting the long-term survival and spread of reintroduced understorey species are poorly known ( Van der Veken et al 2007, 2012Dalrymple et al 2011;Godefroid et al 2011;Drayton and Primack 2012;Maschinski and Haskins 2012).…”

“…Since the majority of studies of the re-establishment of understorey species involved planting beneath an established canopy (e.g., Van der Veken et al 2007, 2012Drayton and Primack 2012), it is unclear whether the high light post-mining environment is conducive for understorey plant establishment. In addition, the presence of an overstorey canopy can exert a significant moderating effect on the understorey micro-climate (von Arx et al 2013).…”

Big moving day for biodiversity? A macroecological assessment of the scope for assisted colonization as a conservation strategy under global warming

“…Nevertheless, it is also becoming clear that many species are dispersing at a slower pace than the climate is shifting [14]. Furthermore, there is increasingly strong evidence that many species have strongly dispersal-limited ranges, e.g., often still being constrained by dispersal in their postglacial range expansion from their ice age refugia [9][10][11]17]. In particular, species with small ranges (often called 'endemic' species) are often constrained to areas that have functioned as long-term refugia due to consistently favorable climate conditions [18,19].…”

Non-random dispersal by ants: Long-term field data versus model predictions of population spread of a forest herb

“…Forest herbs of northern temperate forests in Europe and NE America offer convenient examples of spatially limited species, their local distribution being determined by seed availability and thus dispersal (Ehrlén and Eriksson, 2000;Flinn and Vellend, 2005;van der Veken et al, 2007). Ants are the most common seed dispersal agent for herbs in these forests (Whigham, 2004), and myrmecochory (i.e.…”

“…Because here spread patterns are influenced by environmental differences between stand types (Flinn and Vellend, 2005), such studies need to be supplemented with direct observations of plant population development from known release points in homogenous forest stands. However, studies tracking species' spread following experimental introduction are scarce because they have to be monitored for several years (but see Primack and Miao, 1992;Petersen and Philipp, 2001;van der Veken et al, 2007).…”