Biological soil crusts (BSC) are complex biotic aggregates comprised of lichens, cyanobacteria, algae and other micro\uffe2\uff80\uff90organism that are known to differently affect plant development along life cycle by selecting plant functional traits based on species\uffe2\uff80\uff90specific effects. In addition, functional differences between interacting species should modulate their response ability to other environmental factors. Thus, it should be expected that the effects of the BSC on plants will be significantly determined by the own functional diversity in the community.
To understand the multiple effects of BSC and the extent to which the functional diversity of interacting plant species can modulate their effects on the development of coexisting species, we applied an experimental approach by manipulating the initial functional diversity of the entire annual plant community and BSC conditions in a common garden trial. We crossed three sorts of assemblages built on the basis of plant stature (combinations of only large, or only small, or diverse sized plant species in pots) with three lichen\uffe2\uff80\uff90dominated BSC disturbance scenarios (intact, or tiny mechanically disaggregated, or absent portions of BSC).
BSC strongly affected the establishment and development of gypsophilous annual plants in a complex, multifaceted manner, which shifted throughout the plant life cycle. We demonstrated that lichen\uffe2\uff80\uff90dominated BSC could act as a major physical barrier to the establishment of annual plants at a heterogeneous fine spatial scale. Such a restrictive effect was particularly marked in the presence of intact BSC. However, after annual plants overcame the restrictions imposed by BSC, the same biotic layer facilitated plant growth and fitness, regardless of its physical integrity, resulting in larger plants producing more fruits.
Importantly, our results suggest that the functional diversity structure of the community may also drive growth and fitness of coexisting species by activating alternative coexistence mechanisms such as niche partitioning or competition symmetry. This study highlights the importance of plant neighbourhood features for the performance of interacting species, and confirms a novel, experimental way to explore the effects of community diversity on plants for the interpretation of assembly mechanisms.
Read the free Plain Language Summary for this article on the Journal blog.
Ecological processes such as seed dispersal or plant\uffe2\uff80\uff93plant interactions and environmental constraints such as climate or soil heterogeneity are known to influence establishment, and thus the spatial patterns of plant communities and populations. In this study, we hypothesized that key functional traits such as the specific leaf area (SLA), reproductive ratio (reproductive/vegetative biomass), seed mass and maximum plant height would influence the spatial patterns of individual species in annual, gypsophilous plant communities, and that these effects would be modulated by both the soil surface structure (biocrust) and climate (precipitation) conditions.
We mapped the spatial patterns of all plants found in six 1\uffe2\uff80\uff89\uffc3\uff97\uffe2\uff80\uff891\uffc2\uffa0m plots (more than 1000 individuals per plot) in both the seedling (autumn) and adult stages (spring) under two biocrust experimental conditions (intact vs. disturbed biocrust) during two consecutive years which were contrasted in term of precipitation (dry year and wet year). To assess the spatial patterns of seedlings and adults, we fitted four different spatial point pattern models (i.e. Poisson, inhomogeneous Poisson, Poisson cluster and inhomogeneous Poisson cluster processes) to each of the 242 populations of the 26 most abundant species that had more than 15 individuals per plot.
Most seedling populations exhibited clustered spatial patterns that persisted in the adult stage, which suggests that short\uffe2\uff80\uff90distance dispersal is an adaptive trait for soil specialists such as gypsophilous plants. One\uffe2\uff80\uff90third of the populations fitted an inhomogeneous model best but the physical structure of the biocrust was not related to them. More importantly, we found a connection between the functional strategies of species and the spatial distribution of plants. In particular, during the dry year, irrespective of the biocrust conditions, species with a high SLA and high Rep/Veg mainly exhibited clustered spatial patterns, whereas low SLA and low Rep/Veg were associated with random distributions. Species with heavy and light seed masses had random and clustered patterns, respectively. In both the dry and wet years, species with lower maximum heights had clustered patterns, whereas taller species exhibited random patterns. In addition, species with heavier seeds and greater maximum heights had the largest cluster sizes.
Our results confirm that the spatial patterns of seedlings and adult plants are significantly determined by the functional strategy of each species.
Read the free Plain Language Summary for this article on the Journal blog.
Ecological processes such as seed dispersal or plant\uffe2\uff80\uff93plant interactions and environmental constraints such as climate or soil heterogeneity are known to influence establishment, and thus the spatial patterns of plant communities and populations. In this study, we hypothesized that key functional traits such as the specific leaf area (SLA), reproductive ratio (reproductive/vegetative biomass), seed mass and maximum plant height would influence the spatial patterns of individual species in annual, gypsophilous plant communities, and that these effects would be modulated by both the soil surface structure (biocrust) and climate (precipitation) conditions.
We mapped the spatial patterns of all plants found in six 1\uffe2\uff80\uff89\uffc3\uff97\uffe2\uff80\uff891\uffc2\uffa0m plots (more than 1000 individuals per plot) in both the seedling (autumn) and adult stages (spring) under two biocrust experimental conditions (intact vs. disturbed biocrust) during two consecutive years which were contrasted in term of precipitation (dry year and wet year). To assess the spatial patterns of seedlings and adults, we fitted four different spatial point pattern models (i.e. Poisson, inhomogeneous Poisson, Poisson cluster and inhomogeneous Poisson cluster processes) to each of the 242 populations of the 26 most abundant species that had more than 15 individuals per plot.
Most seedling populations exhibited clustered spatial patterns that persisted in the adult stage, which suggests that short\uffe2\uff80\uff90distance dispersal is an adaptive trait for soil specialists such as gypsophilous plants. One\uffe2\uff80\uff90third of the populations fitted an inhomogeneous model best but the physical structure of the biocrust was not related to them. More importantly, we found a connection between the functional strategies of species and the spatial distribution of plants. In particular, during the dry year, irrespective of the biocrust conditions, species with a high SLA and high Rep/Veg mainly exhibited clustered spatial patterns, whereas low SLA and low Rep/Veg were associated with random distributions. Species with heavy and light seed masses had random and clustered patterns, respectively. In both the dry and wet years, species with lower maximum heights had clustered patterns, whereas taller species exhibited random patterns. In addition, species with heavier seeds and greater maximum heights had the largest cluster sizes.
Our results confirm that the spatial patterns of seedlings and adult plants are significantly determined by the functional strategy of each species.
Read the free Plain Language Summary for this article on the Journal blog.
Ecological processes such as seed dispersal or plant\uffe2\uff80\uff93plant interactions and environmental constraints such as climate or soil heterogeneity are known to influence establishment, and thus the spatial patterns of plant communities and populations. In this study, we hypothesized that key functional traits such as the specific leaf area (SLA), reproductive ratio (reproductive/vegetative biomass), seed mass and maximum plant height would influence the spatial patterns of individual species in annual, gypsophilous plant communities, and that these effects would be modulated by both the soil surface structure (biocrust) and climate (precipitation) conditions.
We mapped the spatial patterns of all plants found in six 1\uffe2\uff80\uff89\uffc3\uff97\uffe2\uff80\uff891\uffc2\uffa0m plots (more than 1000 individuals per plot) in both the seedling (autumn) and adult stages (spring) under two biocrust experimental conditions (intact vs. disturbed biocrust) during two consecutive years which were contrasted in term of precipitation (dry year and wet year). To assess the spatial patterns of seedlings and adults, we fitted four different spatial point pattern models (i.e. Poisson, inhomogeneous Poisson, Poisson cluster and inhomogeneous Poisson cluster processes) to each of the 242 populations of the 26 most abundant species that had more than 15 individuals per plot.
Most seedling populations exhibited clustered spatial patterns that persisted in the adult stage, which suggests that short\uffe2\uff80\uff90distance dispersal is an adaptive trait for soil specialists such as gypsophilous plants. One\uffe2\uff80\uff90third of the populations fitted an inhomogeneous model best but the physical structure of the biocrust was not related to them. More importantly, we found a connection between the functional strategies of species and the spatial distribution of plants. In particular, during the dry year, irrespective of the biocrust conditions, species with a high SLA and high Rep/Veg mainly exhibited clustered spatial patterns, whereas low SLA and low Rep/Veg were associated with random distributions. Species with heavy and light seed masses had random and clustered patterns, respectively. In both the dry and wet years, species with lower maximum heights had clustered patterns, whereas taller species exhibited random patterns. In addition, species with heavier seeds and greater maximum heights had the largest cluster sizes.
Our results confirm that the spatial patterns of seedlings and adult plants are significantly determined by the functional strategy of each species.
Read the free Plain Language Summary for this article on the Journal blog.