Temporal and spatial changes in small mammal communities in a disturbed mountain forest

In 2005–2016, we investigated a secondary succession of small mammal communities in forest ecosystems in High Tatras (Slovakia) disturbed by windstorm and fire. This long-term ecological study confirmed the occurrence of significant temporal and spatial changes in species composition and number of dominant small mammal species. A comparison between disturbed and undisturbed plots indicated notable differences in species richness and abundance. The gradations of dominant small mammal species in disturbed habitats were asynchronous and showed a wider range of amplitude than in the undisturbed plots. An analysis of the temporal and spatial changes in the structure of small mammal communities in relation to selected environmental gradients confirmed the statistically significant effect of secondary succession on species composition, abundance, and exchange in forest ecosystems in the High Tatra Mountains following a disturbance.

Bacterial and fungal communities experience rapid succession during the first year following a wildfire in a California chaparral.

The rise in wildfire frequency in the western United States has increased interest in secondary succession. However, despite the role of soil microbial communities in plant regeneration and establishment, microbial secondary succession is poorly understood owing to a lack of measurements immediately post-fire and at high temporal resolution. To fill this knowledge gap, we collected soils at 2 and 3 weeks and 1, 2, 3, 4, 6, 9, and 12 months after a chaparral wildfire in Southern California. We assessed bacterial and fungal biomass with qPCR of 16S and 18S and richness and composition with Illumina MiSeq sequencing of the 16S and ITS2 amplicons. We found that fire severely reduced bacterial biomass by 47% and richness by 46%, but the impacts were stronger for fungi, with biomass decreasing by 86% and richness by 68%. These declines persisted for the entire post-fire year, but bacterial biomass and richness oscillated in response to precipitation, whereas fungal biomass and richness did not. Fungi and bacteria experienced rapid succession, with 5-6 compositional turnover periods. As with plants, fast-growing surviving microbes drove successional dynamics. For bacteria, succession was driven by the phyla Firmicutes and Proteobacteria, with the Proteobacteria Massilia dominating all successional time points, and the Firmicutes (Domibacillus and Paenibacillus) dominating early- to mid-successional stages (1-4.5 months), while the Proteobacteria Noviherbaspirillum dominated late successional stages (4.5-1 year). For fungi, succession was driven by the phyla Ascomycota, but ectomycorrhizal basidiomycetes, and the heat-resistant yeast, Geminibasidium were present in the early successional stages (1 month). However, pyrophilous filamentous Ascomycetes Pyronema, Penicillium, and Aspergillus, dominated all post-fire time points. While wildfires vastly decrease bacterial and fungal biomass and richness, similar to plants, pyrophilous bacteria and fungi increase in abundance and experience rapid succession and compositional turnover in the first post-fire year, with potential implications for post-fire chaparral regeneration

Changes in Community Composition Following Secondary Succession of a Temperate Oak-hornbeam Forest After Grassland Abandonment and Their Effect on Soil Carbon and Nutrient Pools

To date, changes in C and nutrient cycling during succession are somewhat studied, however, results are often contrasting for different nutrients and successional sequences. Generally, due to increment of litter rich in lignocellulosic components during late succession, mineralization of nutrients is expected to decelerate, and large amounts of nutrients become captivated within tree biomass. We investigated the changes in community composition following secondary succession of oak-hornbeam forest after grassland abandonment, along with the differences in soil chemistry between early- and late- successional stages. We aimed to discover whether late succession increases soil organic C and total N and S pool, but decreases the pools of plant available P and K, and that of micronutrients due to their captivation within the tree biomass.The successional sequence studied had a following pathway: Helictotrichon pubescens haypastures à Brachypodium pinnatum successional grasslands à Cornus sanguinea scrubs à late-successional Populus tremula forests à late-successional oak-hornbeam (Quercus-Carpinus) forests. Total species number was highest in haypastures and lowest in late-successional P. tremula forest. Species richness of haypastures was higher from that of mid-successional scrub and late-successional forest stages. Species richness did not differ between mid-successional scrub and late-successional forest stages. Occurrences of plant species throughout secondary succession was mostly stage-specific; only Fragaria vesca, Ajuga reptans, Cornus sanguinea, Prunus spinosa, and Viola hirta showed survival ability throughout almost all stages. Late-successional forest stages had a higher soil organic carbon (SOC), soil organic matter (SOM), and KA concentration, along with the higher soil C:N and C:S ratio in A horizon compared to early-successional grassland stages, whereas concentrations of plant available P and total N, S, Mn, Zn, Ni, Cu, and Fe remained unaltered.Even though late-successional forest stages tighten the nutrient cycles through nutrient captivation within the tree biomass, we found that late succession efficiently retained PA and micronutrient pools and even increased KA concentration in the A horizon, despite the fact that great amounts of these nutrients were already excluded from the nutrient cycle. Despite the contradicting C inputs, soil total N and S concentration did not differ between late-successional forest and early-successional grassland stages.

Changes in Community Composition Following Secondary Succession of a Temperate Oak-hornbeam Forest After Grassland Abandonment and Their Effect on Soil Carbon and Nutrient Pools

BackgroundTo date, changes in C and nutrient cycling during succession are somewhat studied, however, results are often contrasting for different nutrients and successional sequences. Generally, due to increment of litter rich in lignocellulosic components during late succession, mineralization of nutrients is expected to decelerate, and large amounts of nutrients become captivated within tree biomass. We investigated the changes in community composition following secondary succession of oak-hornbeam forest after grassland abandonment, along with the differences in soil chemistry between early- and late- successional stages. We aimed to discover whether late succession increases soil organic C and total N and S pool, but decreases the pools of plant available P and K, and that of micronutrients due to their captivation within the tree biomass. ResultsThe successional sequence studied had a following pathway: Helictotrichon pubescens haypastures à Brachypodium pinnatum successional grasslands à Cornus sanguinea scrubs à late-successional Populus tremula forests à late-successional oak-hornbeam (Quercus-Carpinus) forests. Total species number was highest in haypastures and lowest in late-successional P. tremula forest. Species richness of haypastures was higher from that of mid-successional scrub and late-successional forest stages. Species richness did not differ between mid-successional scrub and late-successional forest stages. Occurrences of plant species throughout secondary succession was mostly stage-specific; only Fragaria vesca, Ajuga reptans, Cornus sanguinea, Prunus spinosa, and Viola hirta showed survival ability throughout almost all stages. Late-successional forest stages had a higher soil organic carbon (SOC), soil organic matter (SOM), and KA concentration, along with the higher soil C:N and C:S ratio in A horizon compared to early-successional grassland stages, whereas concentrations of plant available P and total N, S, Mn, Zn, Ni, Cu, and Fe remained unaltered.ConclusionsEven though late-successional forest stages tighten the nutrient cycles through nutrient captivation within the tree biomass, we found that late succession efficiently retained PA and micronutrient pools and even increased KA concentration in the A horizon, despite the fact that great amounts of these nutrients were already excluded from the nutrient cycle. Despite the contradicting C inputs, soil total N and S concentration did not differ between late-successional forest and early-successional grassland stages.

Impact of Secondary Succession in the Xerothermic Grassland on the Population of the Eastern Pasque Flower (Pulsatilla patens)—Preliminary Studies

We studied the impact of secondary succession in xerothermic grasslands on a population of Pulsatilla patens, a species of European Community interest. We established two permanent plots with a high number of individuals of P. patens in a xerothermic grassland in Southern Poland. We compared two areas, the first in open grassland (plot A), and the second with overgrowing vegetation (plot B). We assessed the population structure as well as the individual traits of the species. The total abundance of P. patens in the open xerothermic grassland was five times higher than in the overgrowing xerothermic grassland. A randomly clustering distribution was noted only in plot A; in plot B a random type of distribution occurred. The density structure of the rosettes was higher in plot A. The mean number of leaves in rosettes of P. patens as well as dimensions of intermediate stems and leaves of the species is strongly correlated with habitat conditions. The shadowing caused by shrubs and trees and high weeds observed in the overgrowing xerothermic grassland negatively impacted on the number of individuals, distribution, structure and morphology of P. patens.

Secondary succession of woody plants following sand mining in the Soesdyke-Linden area, Guyana: A Chronosequence study

Sandy soils comprise a large proportion of low productivity areas of Guyana on the Soesdyke-Linden Highway, where there is ecological disturbance and evidence of secondary succession after sand mining activities. This study investigated secondary succession of woody plants on abandoned sand mining locations. Secondary succession was studied inferentially by comparing sites in a homogeneous zone that was abandoned at different times post disturbance due to sand mining. Species diversity and community composition at five (5) sites which included an undisturbed area and areas at 3, 5, 10, and 15 years after the disturbance of sand mining were studied. Fifteen 10m x 10m plots were sampled for woody plants with a DBH of more than 2.5cm, and 1m x 1m sub-plots were randomly selected and sampled for seedlings with a DBH less than 2.5cm. A total of 241 plants were recorded, encompassing 22 species across 16 Families. Tapiria marchandii of the family Anacardiaceae dominated the chronosequences of 5, 10, and 15 years and recorded the highest Importance Value Index (IVI) of 112.88, 154.51, and 215.42, respectively. Dimorphandra conjugata of the family Fabaceae also adapted well to conditions post sand mining in the latter chronosequences of 10 and 15 years with IVIs of 54.17 and 38.83, respectively. The youngest site of three years exhibited the highest species diversity post the disturbance of sand mining; however, the undisturbed site possessed the highest overall species diversity. Species diversity of chronosequences decreased with age as competition for limited resources increased and the dominant species proliferated.