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Ecosystem engineers often drive landscape formation and vegetation succession by modifying environmental conditions. Along the Northwestern European coast, dune formation is classically believed to be pioneered by sand couch (Elytrigia juncea), followed by the primary foredune builder marram grass (Calamagrostis arenaria , formerly Ammophila arenaria) once sufficiently large dunes have formed. However, these ideas lack experimental validation, leaving the specific relationship between sand couch, the landscape they form, and marram grass establishment unknown. Here, we experimentally investigated this relationship by planting 975 young marram grass plants in two sand couch dominated, embryonic dune systems. Using structural equation models, we examined the effect of sand couch and the landscape attributes (i.e., elevation, distance to sea and elevation change) on marram grass establishment. Results reveal indirect local inhibition by sand couch via landscape modifications on survival of establishing marram grass. Specifically, sand couch elevated the environment. In turn, elevated areas eroded (i.e., changed in elevation) more in winter, which was the key factor reducing marram grass survival. At the landscape scale, however, we observed the highest survival in relatively stable and sheltered microsites formed because of sand couch induced dune building. While the indirect local inhibition by sand couch for marram grass survival was found at both locations, the direct effect of sand couch on marram grass survival and shoot formation were location and thus context dependent. For marram grass survival, the relation with sand couch was neutral in exposed and positive in sheltered conditions and for shoot formation it was negative in exposed and neutral in sheltered conditions. Similar to scale-dependent interactions found in other biogeomorphic landscapes (e.g., salt marshes, seagrass, mussel beds), we suggest that interspecific facilitation acts on larger spatial scales rather than the commonly suggested small-scale facilitation through created elevation. More specifically, we suggest that dune formation by pioneer species leads to the creation of stable and sheltered microsites beneficial for establishment of later successional species at the landscape-scale. • Field experiment tested how sand couch affects marram grass' establishment. • At the local scale, sand couch indirectly inhibited marram grass' establishment. • Inhibition was caused by erosion which was highest on sand couch-dominated dunes. • Direct effects of sand couch on marram grass' performance were context-dependent. • At the landscape-scale, sand couch facilitates marram grass by creating benign microsites. [ABSTRACT FROM AUTHOR]

Pukaskwa National Park hosts part of a disjunct population of the perennial orchid species Sparrow's-egg Lady's-slipper (Cypripedium passerinum) on the north shore of Lake Superior, Ontario, Canada. Monitoring of C. passerinum within Pukaskwa National Park occurred between 1979 and 2019. During that period, the total number of stalks and the number of C. passerinum colonies within the park have declined, while the proportion of flowering stalks at colonies has increased. Although the number of stalks at extant colonies is stable, this population may be suffering from lack of recruitment and is at risk of extirpation. We hypothesize that the decline and lack of recruitment are a result of changing habitat conditions due to natural and anthropogenic influence. [ABSTRACT FROM AUTHOR]

Differences resulting from the passage of migrating dunes in coastal restinga vegetation in Ilha Grande, Piauí, Brazil were quantified, especially differential survival of tree species (wild Anacardium occidentale, cajuí; Byrsonima crassifolia, muricí) and successional floristic reestablishment. A phytosociological study totalling 108 quadrats (1.08 ha) and satellite images of the area from the past 16 years were used to examine the vegetation of the upwind tracks of two mobile dunes. Quadrats were arranged in four transects along the central and marginal residual ridges of each dune. Most species recorded were herbaceous. Satellite images suggest that plants along the central dune track are buried for approximately 14 years. Some evidence for progressive re‐establishment of woody species was found in the central dune track areas, but not in the marginal areas. No successional patterns were observed in the herbs and subshrubs. Most trees occur along the marginal (longitudinal) residual ridges. Anacardium occidentale and Byrsonima crassifolia predominated among tree species. Anacardium occidentale predominated in abundance, cover, frequency and basal area and survives partial burial when located at the dune track margins. The passage of migratory dunes is important for long term maintenance of the economically important cajuí and muricí populations of Ilha Grande. [ABSTRACT FROM AUTHOR]

Modern coastal dune management is viewed largely through the prism of dune ecology. Achieving maximum biodiversity and preserving priority species are the primary objectives and management is based on interventions (grazing, mowing, burning, reseeding, and artificial destabilisation) to achieve that purpose. Under non‐managed conditions, dune vegetation tends to evolve temporally following well‐established succession patterns that lead to a low diversity scrub or woodland. Achieving high diversity involves resisting succession so as to preserve the more biodiverse, earlier stages. The net effect of management is to create dunes with a network of vegetation types that conform to human wish lists. Rather than natural environments, such interventions reduce dunes to the status of parklands. The natural status of NW European dunes under the conditions of relatively stable sea level and generally limited sand supply over the past few thousand years, and certainly since the Little Ice Age (1650–1800), is to be at a relatively well‐vegetated and advanced stage of succession. Modern dune management effectively amounts to a form of "dune gardening" to maintain a status that is not natural (i.e., attuned to the ambient environment) under contemporary conditions or those of the past two centuries. Current practice is based on a human value‐judgement that views natural succession as the enemy. This view and the resulting actions to resist natural change are at variance with the more pervasive environmental management goal of maintaining natural systems by resisting human intervention. Such an approach reduces dune resilience to global climate change. We advocate an approach that views dunes as combined geomorphological and ecological systems capable of change in response to changing environmental drivers. Modern management of coastal dunes can be described as "dune gardening." This approach is based on the maximisation of biodiversity and resists natural change. We advocate an alternative approach that views dunes as part of a dynamic coastal system and permits them to evolve and change. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

An understanding of plant population dynamics in response to natural and anthropogenic influences is critical for rare species management. We present a long-term study and population viability analysis of a federally threatened monocarpic, Cirsium pitcheri , endemic to the Great Lakes, in northern Michigan. Population growth rates of C . pitcheri were highly variable; only four of the 14 year-pairs studied during the 19 yr study period indicated a growing population ( λ > 1). Elasticity analysis showed population growth was sensitive to seedling recruitment. We manipulated light and litter levels in the growth chamber to simulate natural succession or invasive plants and to determine their effects on seedlings and ultimately, population performance. The absence of shading and litter increased seedling emergence from 8% to 42%, but no simulated population had less than a 5% risk of extinction over a 25-year period. These populations are, strictly speaking, non-viable. Population viability and conservation of this species are linked to recruitment, including seedling success. Control of plant and animal invasive species and addition of greenhouse transplants to increase recruitment may help reverse population declines. [ABSTRACT FROM AUTHOR]

Many introductory ecology textbooks illustrate succession, at least in part, by using certain classic studies (e.g. sand dunes, ponds/bogs, glacial till, and old fields) that substituted space for time (chronosequence) in determining the sequences of the succession. Despite past criticisms of this method, there is continued, often uncritical, use of chronosequences in current research on topics besides succession, including temporal changes in biodiversity, productivity, nutrient cycling, etc. To show the problem with chronosequence-based studies in general, we review evidence from studies that used non-chronosequence methods (such as long-term study of permanent plots, palynology, and stand reconstruction) to test the space-for-time substitution in four classic succession studies. In several cases, the tests have used the same locations and, in one case, the same plots as those in the original studies. We show that empirical evidence invalidates the chronosequence-based sequences inferred in these classic studies. [ABSTRACT FROM AUTHOR]