Changes In Species Diversity Research Articles

ОЦЕНКА ВИДОВОГО РАЗНООБРАЗИЯ ТЛЕЙ (HEMIPTERA, APHIDIDAE) В АГРОЦЕНОЗЕ ОПЫТНОГО ПОЛЯ ВИЗР ПУШКИНСКОГО РАЙОНА САНКТ-ПЕТЕРБУРГА В 2021–2023 гг.

The research was carried out in order to analyze changes in species diversity and the dynamics of aphid abundance within the same agrocenosis under different weather conditions. The species composition and abundance of aphids were monitored using the Malaise trap at the VIZR experimental field (Pushkinsky district of St. Petersburg) during the growing season 2021-2023. During this period, 34 species of phytophages were identified, of which 20 are pests of crops, including 9 species in 2021, 11 species in 2022 and 27 species in 2023. The smallest number of individuals in the trap was observed in 2021 (36 pcs.), in 2022 and 2023 it was about the same (97 and 101 pcs., respectively). The largest number of insect species and individuals in one trap was identified in 2023, which was the result of a favorable interaction of abiotic and biotic factors. In 2021, the traps were dominated by dendrophilous aphids, among which the largest was the European birch aphid.

Impact Assessment of Ports and Effluent Discharge on Macrobenthic Communities in Indian Coastal Ecosystems: A Comprehensive Review

ABSTRACTThe burgeoning industrialization and urbanization along the Indian coastline have led to an increased prevalence of port infrastructure and effluent discharge, raising concerns about their potential impact on the delicate macrobenthic communities in coastal ecosystems. This comprehensive review aims to evaluate and synthesize existing literature on the ecological repercussions of port activities and effluent discharge on macrobenthic organisms in Indian coastal regions. The study encompasses a thorough analysis of relevant research articles, government reports, and scientific databases, focusing on diverse ecosystems such as estuaries, mangroves, and open coastlines. The review discusses the various stressors associated with port operations, including dredging, habitat alteration, and chemical contamination from effluent discharge. Furthermore, it explores the response mechanisms of macrobenthic communities, encompassing changes in species composition, abundance, and diversity. Special attention is given to the potential long‐term impacts on ecosystem functioning and services. The synthesis of available data enables the identification of knowledge gaps and the formulation of recommendations for future research and management strategies. Understanding the cumulative effects of port activities on macrobenthic communities is crucial for developing sustainable practices and policies to mitigate adverse impacts while fostering the resilience of coastal ecosystems in the face of anthropogenic pressures. This review contributes to the growing body of knowledge on the ecological consequences of human activities in Indian coastal areas, providing valuable insights for researchers, policymakers, and environmental managers alike.

Spatial and Temporal Patterns of Grassland Species Diversity and Their Driving Factors in the Three Rivers Headwater Region of China from 2000 to 2021

Biodiversity loss will lead to a serious decline for ecosystem services, which will ultimately affect human well-being and survival. Monitoring the spatial and temporal dynamics of grassland biodiversity is essential for its conservation and sustainable development. This study integrated ground monitoring data, Landsat remote sensing, and environmental variables in the Three Rivers Headwater Region (TRHR) from 2000 to 2021. We established a reliable model for estimating grassland species diversity, analyzed the spatial and temporal patterns, trends of change, and the driving factors of changes in grassland species diversity over the past 22 years. Among models based on diverse variable selection and machine learning methods, the random forest (RF) combined stepwise regression (STEP) model was found to be the optimal model for estimating grassland species diversity in this study, which had an R2 of 0.44 and an RMSE of 2.56 n/m2 on the test set. The spatial distribution of species diversity showed a pattern of abundance in the southeast and scarcity in the northwest. Trend analysis revealed that species diversity was increasing in 80.46% of the area, whereas 16.59% of the area exhibited a decreasing trend. The analysis of driving factors indicated that the changes in species diversity were driven by both climate change and human activities over the past 22 years in the study area, of which temperature was the most significant driving factor. This study effectively monitors grassland species diversity on a large scale, thereby supporting biodiversity monitoring and grassland resource management.

Seasonality Structures Avian Functional Diversity and Niche Packing Across North America.

Assemblages in seasonal ecosystems undergo striking changes in species composition and diversity across the annual cycle. Despite a long-standing recognition that seasonality structures biogeographic gradients in taxonomic diversity (e.g., species richness), our understanding of how seasonality structures other aspects of biodiversity (e.g., functional diversity) has lagged. Integrating seasonal species distributions with comprehensive data on key morphological traits for bird assemblages across North America, we find that seasonal turnover in functional diversity increases with the magnitude and predictability of seasonality. Furthermore, seasonal increases in bird species richness led to a denser packing of functional trait space, but functional expansion was important, especially in regions with higher seasonality. Our results suggest that the magnitude and predictability of seasonality and total productivity can explain the geography of changes in functional diversity with broader implications for understanding species redistribution, community assembly and ecosystem functioning.

Variation in thermal physiology can drive the temperature-dependence of microbial community richness.

Predicting how species diversity changes along environmental gradients is an enduring problem in ecology. In microbes current theories tend to invoke energy availability and enzyme kinetics as the main drivers of temperature-richness relationships. Here we derive a general empirically-grounded theory that can explain this phenomenon by linking microbial species richness in competitive communities to variation in the temperature-dependence of their interaction and growth rates. Specifically, the shape of the microbial community temperature-richness relationship depends on how rapidly the strength of effective competition between species pairs changes with temperature relative to the variance of their growth rates. Furthermore, it predicts that a thermal specialist-generalist tradeoff in growth rates alters coexistence by shifting this balance, causing richness to peak at relatively higher temperatures. Finally, we show that the observed patterns of variation in thermal performance curves of metabolic traits across extant bacterial taxa is indeed sufficient to generate the variety of community-level temperature-richness responses observed in the real world. Our results provide a new and general mechanism that can help explain temperature-diversity gradients in microbial communities, and provide a quantitative framework for interlinking variation in the thermal physiology of microbial species to their community-level diversity.

Management Strategies for Ulex europaeus L. Control in a Native Plant Community in Tenerife, Canary Islands

Invasive plant species have been recognized as adversely affecting native ecosystems. Some of these plant species become problematic in disturbed environments such as urbanized, agricultural, and abandoned developed or farmed land. In some cases, they can dominate the invaded ground, preventing a transition back to the native plant community. In Tenerife (Canary Islands), the invasive plant species Ulex europaeus L. has established dense infestations in abandoned agricultural lands. Removing such invasive species in Tenerife through ecological restoration is crucial for restoring ecosystem functionality and promoting biodiversity. This study evaluates various management methods for U. europaeus in abandoned fields, assessing their impact on species richness, diversity, composition, and regeneration. The findings can inform management strategies to combat this invasive species, contributing to biodiversity conservation and ecosystem resilience. The study was conducted in two highly invaded areas, evaluating chemical (C), mechanical (M), mechanical and chemical (MC), and mechanical, chemical, and plantation treatments (MCP), along with a control, to analyze changes in species richness, diversity, and plant community. Results indicate that U. europaeus remains capable of reoccupying treated areas. The different treatments led to differences in species richness and composition. The MCP treatment yielded the best results if the planted native species grew faster than Ulex europaeus, preventing its establishment due to its shade-intolerant nature. However, continual control is required to eliminate U. europaeus regeneration from seeds that can persist for at least 30 years.

Temporal dynamics of acoustic diversity in managed forests

IntroductionIn production forests, management can have cascading effects on biodiversity and ecosystem services. Acoustic diversity reflects the diversity of vocalizing animals and has also considerable recreational value for human well-being, but the relationship between acoustic diversity and forest management remains largely unexploredMethodWe recorded acoustic diversity on forest plots along a gradient of silvicultural management intensity (SMI) in three regions of Germany. We explored the diurnal and seasonal temporal dynamics in acoustic diversity index (ADI) from March to July using generalized additive mixed models (GAMMs). We further investigated the interrelation between acoustic diversity and silvicultural management intensity, forest structural diversity, as well as tree diversity, bird species richness and abundance using structural equation modeling (SEM).ResultsSilvicultural management intensity had significant effects on the temporal dynamics of ADI in May and June from dawn till dusk, but variance explained by SMI was low. We confirmed our hypothesis that ADI was reduced by SMI due to its cascading effects on forest structural diversity and bird species richness and abundance.DiscussionAcoustic diversity indices can provide valuable insights into how forest management affects the acoustic activity of soniferous communities. We discuss how this can indicate both changes in species diversity as well as their vocal activity. We further address potential implications for forest management.

Litter mixture effects on nitrogen dynamics during decomposition predominantly vary among biomes but little with litter identity, diversity and soil fauna

Nitrogen (N) is essential for net primary production, with much of the required N in terrestrial ecosystems derived from recycling via litter decomposition. The diversity and identity of plant species and decomposer organisms affect N cycling during litter decomposition, yet the generality and magnitude of these effects remain uncertain. To fill this gap, a decomposition experiment with four leaf litter species that differed widely in initial litter quality was conducted including single species and all possible multispecies mixtures, with and without microarthropods access across a broad latitudinal gradient covering four major forest biomes of the Northern Hemisphere. The results showed that leaf litter N dynamics (both N loss and N immobilization) in single species treatments depended primarily on litter species identity and the local environmental context. We found strong mixture effects, that overall tended to increase N loss and to reduce 15N transfer. The relative mixture effects on N dynamics differed among forest biomes, but were little affected by the other factors we manipulated. The N loss of individual litter species in mixtures not only depended on litter identity and soil microarthropod access, but also on forest biomes; while 15N transfer depended strongly on litter mixing, independently of litter species richness or composition of the mixtures. Litter N dynamics were mainly driven by a small subset of litter traits, regardless of species richness and microarthropod access. Overall, our results highlight that litter mixture strongly affects N dynamics during decomposition, with the mixture effects predominantly varying among forest biomes but little with litter identity, diversity and microarthropod access. To improve predictions on how changes in tree species composition and diversity may impact nutrient dynamics in forest ecosystems in face of increasing N deposition, interactions between litter and soil but also within litter mixtures need closer attention.

Understanding processes underlying cross-taxon congruence in species composition along elevational gradients

Changes in species diversity of different taxa along environmental gradients are usually correlated, resulting in a pattern called cross-taxon congruence. This pattern can be due to functional relationships between taxa, a common response to niche-related processes, or stochastic processes. However, it remains unclear the extent to which they contribute to the association among patterns of changes in species composition, (i.e., beta diversity), and whether these changes are related to species nestedness and turnover. Here we described patterns of change in the taxonomic composition of plant and orthopteran assemblages along an elevational gradient in Cordoba province, central Argentina. We assessed cross-taxon congruence and identified the main environmental variables accounting for such patterns. Mantel correlations showed congruence between the patterns of taxonomic dissimilarity of plants and orthopterans. According Generalized disiimilarity models (GDM) the main environmental variables driving the patterns were temperature for both taxa, and changes in soil nutrient content for plants, spatial effects were also found. Beta diversity was mainly due to species turnover for orthopterans and plants, indicating replacement by species adapted to elevational conditions. Niche-related process, such as environmetal filtering, along with neutral processes may have contributed to cross-taxon congruence in beta diversity.

Soil eDNA biomonitoring reveals changes in multitrophic biodiversity and ecological health of agroecosystems

Soil health is integral to sustainable agroecosystem management. Current monitoring and assessment practices primarily focus on soil physicochemical properties, yet the perspective of multitrophic biodiversity remains underexplored. Here we used environmental DNA (eDNA) technology to monitor multitrophic biodiversity in four typical agroecosystems, and analyzed the species composition and diversity changes in fungi, bacteria and metazoan, and combined with the traditional physicochemical variables to establish a soil health assessment framework centered on biodiversity data. First, eDNA technology detected rich multitrophic biodiversity in four agroecosystems, including 100 phyla, 273 classes, 611 orders, 1026 families, 1668 genera and 1146 species with annotated classification, and the relative sequence abundance of dominant taxa fluctuates tens of times across agroecosystems. Second, significant differences in soil physicochemical variables such as organic matter (OM), total nitrogen (TN) and available phosphorus (AP) were observed among different agroecosystems, nutrients were higher in cropland and rice paddies, while heavy metals were higher in fish ponds and lotus ponds. Third, biodiversity metrics, including α and β diversity, also showed significant changes across agroecosystems, the soil biota was generally more sensitive to nutrients (e.g., OM, TN or AP), while the fungal communities were mainly affected by heavy metals in October (e.g., Cu and Cr). Finally, we screened 48 sensitive organismal indicators and found significant positive consistency between the developed eDNA indices and the traditional soil quality index (SQI, reaching up to R2 = 0.58). In general, this study demonstrated the potential of eDNA technology in soil health assessment and underscored the importance of a multitrophic perspective for efficient monitoring and managing agroecosystems.

Collembola and ants: Influence of trails of red wood ants (Formica lugubris) on the community of soil springtails

Red wood ants are keystone species in forest ecosystems. Because ants are active polyphagous predators, they control the abundance of other arthropods. In addition to direct effects on other species, there are a number of indirect effects caused by ants. In our study, we investigated the influence of ants on springtails, which they rarely come into contact with. Springtails have been set as a model group to assess the state of soil animals, since they are one of the most numerous and widespread groups of soil microarthropods. They are characterized by high sensitivity to environmental changes. The basic characteristics (abundance, species richness, and species diversity) of the springtail community and the response of certain species to the presence of ant trails have been studied. The total abundance and species richness of springtails decreased along ant trails. Among occurred species Parisotoma ParIsotoma notabilis, Lepidacyrtus lignorum, Isotomiella minor, Desoria tigrina, and Pseudasinella alba are the most numerous species both along ant trails and in control samples. There are no significant changes in species diversity (assessed by the Shannon-Weaver index). Species structure of springtail communities along ant trails and in control is different. Two groups of common Collembola species are identified: (1) increasing their numbers in the presence of ants, (2) on the contrary, decreasing. The presence of ants in a forest ecosystem influences the soil springtail community, although ant-Collembola interactions are indirect.

Diversity-biomass relationships are shaped by tree mycorrhizal associations and stand structural diversity at different spatial scales

Diversity-biomass relationships (DBRs) in terrestrial ecosystems tend to vary across spatial scales, but, particularly in hyperdiverse forests, the mechanisms driving these trends remain uncertain. Until now, few have simultaneously investigated the connections between tree species diversity, stand structural diversity, mycorrhizal associations, and ecosystem functioning. In addition, DBRs have only been studied at limited spatial scales, with limited focus on the direct and indirect effects of environmental factors. We addressed these research gaps using a 30-ha forest dynamics plot located in Pu'er City, Southwest China. Through piecewise structural equation models, we quantified the direct effects of tree species diversity (α, β, γ), stand structural diversity, mycorrhizal associations (AM, EcM), and the environmental factors (soil fertility and topography), as well as the indirect effects of the environmental factors on aboveground tree biomass across spatial scales ranging from 400 to 230,400 ​m2. We hypothesized that complex interactions among these factors underpin the variation in DBRs in natural ecosystems across spatial scales. Our results showed that environmental conditions indirectly affected the tree biomass via changes in tree species diversity, and these effects became stronger as the spatial scale increased. At small to moderate spatial scales, environmental factors were more predictive of tree biomass than tree species diversity (or its components); the effects of stand structural diversity on biomass also gradually increased with spatial scale. Conversely, from the intermediate to the largest spatial scales, mycorrhizal associations gradually became the best predictors of DBR dynamics. Our research offers novel empirical evidence demonstrating the importance of environmental conditions, structural diversity, and mycorrhizal associations in shaping cross-scale DBRs. Future comprehensive studies should consider these factors to assess the mechanisms shaping scale-dependent DBRs in complex natural ecosystems.

Changes in Species Composition, Diversity, and Biomass of Secondary Dry Grasslands Following Long-Term Mowing: A Case Study in Hungary

Changes in Species Composition, Diversity, and Biomass of Secondary Dry Grasslands Following Long-Term Mowing: A Case Study in Hungary

Drivers of β-diversity and its component-dependence along the natural restoration in an extremely heterogeneous forest ecosystem

β-diversity usually refers to species turnover along a gradient or changes in species diversity between communities. It is a key concept in understanding the mechanisms of biodiversity pattern formation. However, the component dependence and the driving factors of β-diversity during natural restoration remain unclear. In this study, a series of forest dynamic plots (FDPs) were established through the natural restoration stages in degraded karst forests, including the shrub-canopy mixed forest stage (SC), the secondary-growth forest stage (SG), and the old-growth forest stage (OG). After comparing species composition during natural restoration and its dependence on species turnover and nestedness, it was found that natural restoration significantly influenced the species composition by altering the species turnover in degraded karst forests rather than the nestedness. The contribution of turnover to β-diversity gradually increased, while the contribution of nestedness decreases gradually. Furthermore, the PER-SIMPER method was used to quantify the first-order assembly process that drives variations in species composition during restoration stages. To identify the factors influencing β-diversity, both variation partitioning analysis and a random forest model were employed. The results suggested that differences in species compositions across restoration stages were mainly driven by stochastic processes, and the deterministic processes were strengthened during the natural restoration. In addition, topographic factors contributed more to β-diversity than soil nutrient factors. This study highlighted changes in component dependence of degraded karst forests during natural restoration and emphasized the importance of a more comprehensive framework in assessing the restoration of degraded forest ecosystems. More attention should be paid to topographic structure in understanding biodiversity patterns, especially in highly heterogeneous forest ecosystems.

The impact of the Qinghai-Tibet highway on plant community and diversity.

Roads are an increasingly prevalent form of human activity that drives the decrease in plant community functions and threatens global biodiversity. However, few studies have focused on the changes in the function and diversity of alpine meadows caused by road infrastructure in the Tibetan Plateau. In this study, the changes in species diversity, functional diversity, and community stability were examined at different distances from the Qinghai-Tibet highway. The results showed that the road intensified the degradation of vegetation, which significantly altered species diversity and community structure. This effect gradually decreased from near to far from the highway. Plant community cover and species diversity were highest at intermediate distances (50-100 m) from the roadway; species diversity and stability were lowest in the grassland most disturbed by the road (0m), and species diversity and functional diversity tended to stabilize farther away from the road (250m). Our findings indicate that changes in species diversity are synchronized with changes in functional diversity, which largely determines the outcome of degraded grassland community diversity and stability. Our results provide a reference point for restoring degraded alpine areas and mitigating the ecological impacts of roads.

One-year effects of stand age, pre-fire treatments, and hillslope aspect on recovery of plant diversity and soil properties in a Mediterranean forest burnt by a severe wildfire

Although several management options are adopted to redirect post-fire forest ecosystems towards less vulnerable and more resilient and functional communities, little is known about the interactions among tree stand age, pre-fire forest management, and slope aspects, and their consequences for plant species and soil properties recovery immediately after severe wildfires. To address this knowledge need, this study evaluates the post-fire changes in species richness and diversity (with a specific focus on regeneration mechanisms and life forms) of regenerating plants as well as the main physico-chemical and biological properties of burned soils with the reciprocal relations. Plant cover and diversity, and many soil properties have been monitored in forests of southeast Spain with mature, middle and young stands, presence of pre-fire treatments or not, and north and south hillslopes about one year after the fire. To this aim, the reciprocal relationships among soil properties and plants were evaluated adopting a combination of statistical techniques (PERMANOVA, Non-metric Multi-Dimensional Scaling, Distance-based Linear Modelling, Distance-based Redundancy Analysis, and Spearman correlation analysis). The damage to soil and vegetation was so high that both plants and pre-fire soil properties slowly recovered. Only a few life forms of vegetation (geophytes and herbaceous chamaephytes) were influenced by the stand age. If combined with soil aspect, stand age resulted in significantly lower germinating species in mature stands and lower resprouters in young stands, both on south hillslopes. Plant diversity was high, and the post-fire regeneration did not change the species richness and evenness. The post-fire changes in soil properties were limited, and only slight small differences in pH and betaglucosidase among stands of different age were found. No evident associations between soil properties and plant diversity were revealed by the low correlation coefficient. The low variance in plant cover and diversity, as well as in soil properties, resulted in a low accuracy of the dbRDA model to reproduce its variability among sites with different pre-fire characteristics.

Ecological Impacts of Coastal Protection on the Vegetation of Sandy Coasts at the German Baltic Sea Coast

Sand nourishments and groynes as coastal protection measures (CPM) address similar challenges on sandy coasts but take different approaches: while groynes are intended to reduce alongshore sediment transport and erosion, nourishments add new sediment to the system to compensate for erosion. The aim of this study is to compare the ecological effects of such measures on the vegetation. To this end, nutrient analysis and botanical mappings were carried out on a site with installed groynes, a site where sand nourishments are regularly carried out, and a control site without any CPM. In addition to an increase in nutrient availability after the sand nourishment, significant changes in plant species diversity and composition were also measured. The number of higher plants, mosses, and lichen species was lower at the nourishment site. The opposite impacts were observed at the groyne site: an increase in sediment cover by higher plants and mosses and a distinct increase in lichen species. The results suggest that groynes lead to a stabilization of the coastal system and enable dense vegetation growth. In contrast, sand nourishments lead to nutrient input and unstable habitat conditions, attracting certain plant communities but preventing the establishment of ground-covering vegetation.

The Mosquito Fauna of Arizona: Species Composition and Public Health Implications.

Arizona is home to many mosquito species, some of which are known vectors of infectious diseases that harm both humans and animals. Here, we provide an overview of the 56 mosquito species that have been identified in the State to date, but also discuss their known feeding preference and the diseases they can (potentially) transmit to humans and animals. This list is unlikely to be complete for several reasons: (i) Arizona's mosquitoes are not systematically surveyed in many areas, (ii) surveillance efforts often target specific species of interest, and (iii) doubts have been raised by one or more scientists about the accuracy of some collection records, which has been noted in this article. There needs to be an integrated and multifaceted surveillance approach that involves entomologists and epidemiologists, but also social scientists, wildlife ecologists, ornithologists, representatives from the agricultural department, and irrigation and drainage districts. This will allow public health officials to (i) monitor changes in current mosquito species diversity and abundance, (ii) monitor the introduction of new or invasive species, (iii) identify locations or specific populations that are more at risk for mosquito-borne diseases, and (iv) effectively guide vector control.

Temporal changes in species richness, composition and diversity of the forest stands over 36-year period, Western Himalaya, India

This study investigates the temporal changes in species richness, composition, and diversity in forest stands spanning a 36-year period in the Western Himalaya. Four forest stands (subtropical Sal-forest, subtropical Chir-pine forest, temperate Banj-oak forest, and temperate Mixed-oak Forest) studied in 1980–1981 were resurveyed using similar methods. Over the past 36 years, 19 new species have been recorded in the four stands; eight species planted and eleven species naturally introduced. Dominant species continue to dominate in the forest stands. However, their contribution to the total tree density has decreased over the year. Species diversity, richness, and evenness increased in all forests except the Sal stand. Three species were newly introduced in the Sal stand, seven in the Chir-pine stand, eight in the Banj-oak stand, and seven in the Mixed-oak stand. The highest similarity in species composition was observed in the Sal stand (59 %), followed by the mixed-oak stand (57 %), Chir-pine stand (50 %), and Banj-oak stand (47 %). The results indicate an increase in tree density across all sites, with the Mixed-oak forest exhibiting the highest increase in tree density due to least biotic pressure. The findings of this study, based on two-time composition datasets, provide valuable insights into forest dynamics, supporting biodiversity conservation and management planning.

Adaptive grazing enhances plant species richness and density in the soil seed bank in a semi-arid grassland

The soil seed bank plays a key role in vegetation resilience under environmental disturbances, and is especially important for the restoration of degraded vegetation. However, the responsive dynamics of the soil seed bank to animal grazing and its potential in the restoration of grazing degraded steppe grassland remain unclear. Here we examined the changes in plant species diversity and density in both the soil seed bank and the aboveground vegetation of a natural grassland along an experimental gradient of four grazing intensities (nil, light, moderate and heavy grazing) in an adaptive grazing management system that ensures grassland residual cover was always above a certain criteria. The grassland is a typical steppe dominated by Leymus chinensis, Stipa grandis, and Cleistogenes squarrosa in central Inner Mongolia, China. We found that (i) plant species richness and density of the seed bank in the top 10 cm soil layer increased with grazing intensity, though the density of the seed bank in the top 5 cm soil layer showed an decrease. (ii) Moderate and heavy grazing significantly decreased the density of perennial but increased annual and biennial plants in the top 5 cm soil layer, which dominate the changes in the top 10 cm soil layer. (iii) Plant species richness and density in the aboveground vegetation also increased with grazing intensity, so did the similarity between the species composition of the soil seed bank and aboveground vegetation in the top 10 cm. The increase in the richness and density of annual and biennial species dominated the responsive changes to grazing of the soil seed bank and aboveground vegetation in the studied grassland. Our results provide a reference basis for grazing management in the region from the perspective of the soil seed bank, and suggest that the adaptive grazing system with grassland residual height controlled above a criterion benefits to the soil seed bank thus the re-generation of vegetation.