Patterns of Understory Community Assembly and Plant Trait-Environment Relationships in Temperate SE European Forests

We analyzed variation in the functional composition and diversity of understory plant communities across different forest vegetation types in Slovenia. The study area comprises 10 representative forest sites covering broad gradients of environmental conditions (altitude, geology, light availability, soil type and reaction, nutrient availability, soil moisture), stand structural features and community attributes. The mean and variation of the trait values were quantified by community-weighted means and functional dispersion for four key plant functional traits: plant height, seed mass, specific leaf area and leaf dry matter content. At each study site, forest vegetation was surveyed at two different spatial scales (4 and 100 m2) in order to infer scale-dependent assembly rules. Patterns of community assembly were tested with a null model approach. We found that both trait means and diversity values responded to conspicuous gradients in environmental conditions and species composition across the studied forests. Our results mainly support the idea of abiotic filtering: more stressful environmental conditions (e.g., high altitude, low soil pH and low nutrient content) were occupied by communities of low functional diversity (trait convergence), which suggests a selective effect for species with traits adapted to such harsh conditions. However, trait convergence was also detected in some more resource-rich forest sites (e.g., low altitude, high soil productivity), most likely due to the presence of competitive understory species with high abundance domination. This could, at least to some extent, indicate the filtering effect of competitive interactions. Overall, we observed weak and inconsistent patterns regarding the impact of spatial scale, suggesting that similar assembly mechanisms are operating at both investigated spatial scales. Our findings contribute to the baseline understanding of the role of both abiotic and biotic constraints in forest community assembly, as evidenced by the non-random patterns in the functional structure of distinct temperate forest understories.

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Tropical land-use change alters trait-based community assembly rules for dung beetles and birds

Oecologia ◽

10.1007/s00442-020-04829-z ◽

2021 ◽

Author(s):

Felicity A. Edwards ◽

David P. Edwards ◽

Keith C. Hamer ◽

Tom M. Fayle

Keyword(s):

Community Assembly ◽

Species Interactions ◽

Spatial Scales ◽

Dung Beetles ◽

Habitat Associations ◽

Habitat Modification ◽

Forest Community ◽

Primary Forest ◽

Disturbance Gradient ◽

Habitat Generalists

AbstractTropical rainforest disturbance and conversion are critical drivers of biodiversity loss. A key knowledge gap is understanding the impacts of habitat modification on mechanisms of community assembly, which are predicted to respond differently between taxa and across spatial scales. We use a null model approach to detect trait assembly of species at local- and landscape-scales, and then subdivide communities with different habitat associations and foraging guilds to investigate whether the detection of assembly mechanisms varies between groups. We focus on two indicator taxa, dung beetles and birds, across a disturbance gradient of primary rainforest, selectively logged rainforest, and oil palm plantations in Borneo, Southeast Asia. Random community assembly was predominant for dung beetles across habitats, whereas trait convergence, indicative of environmental filtering, occurred across the disturbance gradient for birds. Assembly patterns at the two spatial scales were similar. Subdividing for habitat association and foraging guild revealed patterns hidden when focusing on the overall community. Dung beetle forest specialists and habitat generalists showed opposing assembly mechanisms in primary forest, community assembly of habitat generalists for both taxa differed with disturbance intensity, and insectivorous birds strongly influenced overall community assembly relative to other guilds. Our study reveals the sensitivity of community assembly mechanisms to anthropogenic disturbance via a shift in the relative contribution of stochastic and deterministic processes. This highlights the need for greater understanding of how habitat modification alters species interactions and the importance of incorporating species’ traits within assessments.

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Comparison of Forest Species- Diversity and Composition Inside and Outside of the Holedná Game Reserve (The City of Brno, Czech Republic)

Journal of Landscape Ecology ◽

10.2478/jlecol-2021-0001 ◽

2021 ◽

Vol 14 (1) ◽

pp. 1-18

Author(s):

Radomír Řepka ◽

Jarmila Keclíková ◽

Jan Šebesta

Keyword(s):

Czech Republic ◽

Species Diversity ◽

Forest Vegetation ◽

Forest Community ◽

Herb Layer ◽

Forest Species ◽

Significant Difference ◽

Game Reserve ◽

The Impact ◽

The City

Abstract The impact of ungulates on the forest vegetation has far-reaching consequences: it decreases species diversity and the production of biomass, causes soil dehydration, erosion and eutrophication the entire forest community. The article addresses the influence of fallow deer and mouflon on the forest vegetation in the Holedná game reserve (western border of the city of Brno, South Moravia, Czech Republic) and compares differences with the forests adjacent to the game reserve. Sixty localities were distributed randomly and phytosociological relevés subsequently recorded there according to the age of the stands inside and outside of the game reserve. The differences in floristic composition were compared for trees, shrubs and herbs, the herb layer species number, the diversity indices and the values of Ellenberg indicators. In the game reserve, a significant difference was found in the coverage of the herb and shrub layer, which was significantly lower than outside the territory. Furthermore, the increased amount of nitrophilous, heliophytes and ruderal herb species inside the game reserve exhibited affiliation to the interior of game reserve. Besides, young trees and woody sapling were less abundant or even missing inside of game reserve. By contrast, the frequency of typical species of oak-hornbeam forests was higher outside game reserve. Due to the higher number of animals and consequent disturbances, nitrophilous plant species dominate in the herb layer of the game reserve, while forest species are more often represented outside it.

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Elasmobranch Use of Nearshore Estuarine Habitats Responds to Fine-Scale, Intra-Seasonal Environmental Variation: Observing Coastal Shark Density in a Temperate Estuary Utilizing Unoccupied Aircraft Systems (UAS)

Drones ◽

10.3390/drones4040074 ◽

2020 ◽

Vol 4 (4) ◽

pp. 74

Author(s):

Alexandra E. DiGiacomo ◽

Walker E. Harrison ◽

David W. Johnston ◽

Justin T. Ridge

Keyword(s):

Environmental Conditions ◽

Spatial Scales ◽

Shark Species ◽

Rachel Carson ◽

Generalized Linear Modelling ◽

Aircraft System ◽

Study Sites ◽

Dynamic Habitat ◽

Physical And Chemical ◽

The Impact

Many coastal shark species are known to use estuaries of the coastal southeastern United States for essential purposes like foraging, reproducing, and protection from predation. Temperate estuarine landscapes, such as the Rachel Carson Reserve (RCR) in Beaufort, NC, are dynamic habitat mosaics that experience fluctuations in physical and chemical oceanographic properties on various temporal and spatial scales. These patterns in abiotic conditions play an important role in determining species movement. The goal of this study was to understand the impact of environmental conditions around the RCR on shark density within the high-abundance summer season. Unoccupied Aircraft System (UAS) surveys of coastal habitats within the reserve were used to quantify shark density across varying environmental conditions. A combination of correlation analyses and Generalized Linear Modelling (GLM) revealed that density differs substantially across study sites and increases with rising water temperatures, conclusions that are supported by previous work in similar habitats. Additionally, density appears to increase moving towards dawn and dusk, potentially supporting crepuscular activity in coastal estuarine areas. By describing shark density dynamics in the RCR, this study provides new information on this population and presents a novel framework for studying elasmobranchs in temperate estuaries.

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Functional Divergence between Várzea and Igapó Forests: A Study of Functional Trait Diversity in the Colombian Orinoco Basin

Forests ◽

10.3390/f11111172 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1172

Author(s):

Diana Bonilla ◽

Ana M. Aldana ◽

Sasha Cárdenas ◽

Adriana Sanchez

Keyword(s):

Plant Species ◽

Functional Diversity ◽

Functional Traits ◽

Community Assembly ◽

Forest Type ◽

Functional Divergence ◽

Dry Matter Content ◽

Functional Richness ◽

Flooded Forests ◽

The Impact

Research Highlights: Functional diversity studies help to better understand how organisms respond to different environmental conditions. Conditions in tropical flooded forests are highly variable, including levels of nutrient availability, pH, and flood depth, but few studies have explored the impact of variation in these factors on plant functional diversity. Background and Objectives: In the Orinoco basin, as in the Amazon, floodplain forests have been classified into várzea (white-water rivers, with nutrient-rich soils) and igapó (black-water rivers, associated with nutrient-poor soils). We evaluated the functional diversity of plant species in várzea and igapó, as well as the influence of external and internal filters on the plant community assembly of each forest type, and compared our results with studies in the Amazon basin. Materials and Methods: Six functional traits were recorded in the várzea and igapó forests of the Colombian Orinoco basin (one-hectare plot for each forest type, with no replicates). We evaluated plant species diversity (richness, Fisher’s α, Shannon and Simpson indices), as well as functional diversity (functional richness, functional evenness, functional divergence, and functional dispersion) and the influence of external and internal filters, based on a comparison of variance at different organizational levels. Results: A high functional differentiation between várzea and igapó was found, as well as a high functional divergence within each forest type. We also observed a greater influence of internal filters on the community assembly of both forest types, compared to external filters. Functional traits such as wood density and leaf dry matter content, showed the same patterns as the várzea and igapó forests in the Amazon. Conclusions: Despite the low taxonomic and functional richness, there is high functional divergence within flooded forests. We also show that in forests under stress (e.g., from flooding), internal filters can be key in assembling communities and promote high functional divergence. Given that the functional diversity of the várzea and igapó in the Orinoco is largely unexplored, we highlight the need for more research for the effective conservation of these flooded forests.

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Divergent Abiotic Stressors Drive Grassland Community Assembly of Tibet and Mongolia Plateau

Frontiers in Plant Science ◽

10.3389/fpls.2021.715730 ◽

2022 ◽

Vol 12 ◽

Author(s):

Jianming Wang ◽

Mingxu Li ◽

Li Xu ◽

Congcong Liu ◽

Pu Yan ◽

...

Keyword(s):

Community Assembly ◽

Future Climate Change ◽

Dry Matter Content ◽

Grassland Community ◽

Plant Trait ◽

Abiotic Stressors ◽

Trait Convergence ◽

The Mean ◽

Mean Variance ◽

Skewness And Kurtosis

Multiple ecological processes simultaneously govern community assembly, but it remains unclear how abiotic stressors regulate the relative importance of these processes among different biogeographic regions. Therefore, we conducted a comprehensive study on the responses of community assembly to varying environmental gradients, using the mean, variance, skewness, and kurtosis of plant height (height), specific leaf area (SLA) and leaf dry matter content (LDMC) distributions on the Tibetan Plateau (TP) and the Mongolian Plateau (MP). Our results showed that the prevalence of trait convergence across all grasslands in both TP and MP seem to be the result of abiotic filtering or weaker competitive exclusion etc. These trait-convergence assembly processes decrease the functional dispersion but increase the evenness of the trait frequency distribution. The mean, variance, skewness, and kurtosis responses of grassland communities to abiotic stress varied between the TP and MP. On average, plant trait distribution was mainly driven by temperature on the TP, and low-temperature stress altered the community assembly rules. In contrast, water availability shaped plant trait frequency distributions on the MP, and drought stress mediated the balance between different assembly processes. Our results provide empirical evidence that divergent abiotic stressors regulate the grassland community assembly on the TP and MP. Together, our study speculates that different aspects of future climate change, such as climate warming and changing precipitation patterns, on community assembly are dependent on regional climatic regimes.

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The impact of deer on forest vegetation in Pennsylvania

10.2737/ne-gtr-65 ◽

1981 ◽

Author(s):

David A. Marquis ◽

Ronnie Brenneman

Keyword(s):

Forest Vegetation ◽

The Impact

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Scale dependence of galaxy biasing investigated by weak gravitational lensing: An assessment using semi-analytic galaxies and simulated lensing data

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732248 ◽

2018 ◽

Vol 613 ◽

pp. A15 ◽

Cited By ~ 13

Author(s):

Patrick Simon ◽

Stefan Hilbert

Keyword(s):

Gravitational Lensing ◽

Spatial Scales ◽

Scale Dependence ◽

Reconstruction Technique ◽

Weak Gravitational Lensing ◽

Physical Scale ◽

The Galaxy ◽

Galaxy Bias ◽

The Impact ◽

Lens Galaxies

Galaxies are biased tracers of the matter density on cosmological scales. For future tests of galaxy models, we refine and assess a method to measure galaxy biasing as a function of physical scalekwith weak gravitational lensing. This method enables us to reconstruct the galaxy bias factorb(k) as well as the galaxy-matter correlationr(k) on spatial scales between 0.01hMpc−1≲k≲ 10hMpc−1for redshift-binned lens galaxies below redshiftz≲ 0.6. In the refinement, we account for an intrinsic alignment of source ellipticities, and we correct for the magnification bias of the lens galaxies, relevant for the galaxy-galaxy lensing signal, to improve the accuracy of the reconstructedr(k). For simulated data, the reconstructions achieve an accuracy of 3–7% (68% confidence level) over the abovek-range for a survey area and a typical depth of contemporary ground-based surveys. Realistically the accuracy is, however, probably reduced to about 10–15%, mainly by systematic uncertainties in the assumed intrinsic source alignment, the fiducial cosmology, and the redshift distributions of lens and source galaxies (in that order). Furthermore, our reconstruction technique employs physical templates forb(k) andr(k) that elucidate the impact of central galaxies and the halo-occupation statistics of satellite galaxies on the scale-dependence of galaxy bias, which we discuss in the paper. In a first demonstration, we apply this method to previous measurements in the Garching-Bonn Deep Survey and give a physical interpretation of the lens population.

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Morphological Variations of Wild Populations of Brycon dentex (Characidae, Teleostei) in the Guayas Hydrographic Basin (Ecuador). The Impact of Fishing Policies and Environmental Conditions

Animals ◽

10.3390/ani11071901 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1901

Author(s):

Ana Gonzalez-Martinez ◽

Carmen De-Pablos-Heredero ◽

Martin González ◽

Jorge Rodriguez ◽

Cecilio Barba ◽

...

Keyword(s):

Discriminant Analysis ◽

Environmental Conditions ◽

Anthropogenic Activity ◽

Freshwater Species ◽

Fishing Pressure ◽

Wild Populations ◽

Morphometric Variation ◽

Morphological Variations ◽

Body Development ◽

The Impact

The Guayas, located in Ecuador, is the largest basin in the Pacific Ocean and has an inventory of 123 native freshwater species. Most of these are endemic species that are threatened or at-risk due to anthropogenic activity and the modification, fragmentation, and destruction of habitats. The aim of this study was to determine the morphometric variation in three wild populations of Brycon dentex in the Guayas basin rivers and their connections to fishing management and environmental conditions. A total of 200 mature fish were captured, and 26 morphometric parameters were measured. The fishing policies (Hypothesis 1) and environmental conditions (Hypothesis 2) were considered fixed factors and were validated by t-tests. The morphological variation among the three populations (Hypothesis 3) was validated through a discriminant analysis. Fishing policies and resource management were found to generate morphological differences associated with body development. In addition, the environmental conditions were found to influence the size and structure of Brycon dentex populations. The analyzed populations were discriminated by the generated morphometric models, which differentiated Cluster 1 (Quevedo and Mocache rivers) with high fishing pressure from Cluster 2 (Pintado river) with medium–low fishing pressure. Morphometric differentiation by discriminant analysis is a direct and economic methodology that can be applied as an indicator of diversity maintenance.

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Successive Harvests Modulate the Productive and Physiological Behavior of Three Genovese Pesto Basil Cultivars

Agronomy ◽

10.3390/agronomy11030560 ◽

2021 ◽

Vol 11 (3) ◽

pp. 560

Author(s):

Luigi Formisano ◽

Michele Ciriello ◽

Christophe El-Nakhel ◽

Marios C. Kyriacou ◽

Youssef Rouphael

Keyword(s):

Dry Matter ◽

Co2 Assimilation ◽

Stomatal Resistance ◽

Matter Content ◽

Dry Matter Content ◽

Technological Parameters ◽

Net Co2 Assimilation ◽

Dry Biomass ◽

Crop Cycle ◽

The Impact

In the Italian culinary tradition, young and tender leaves of Genovese basil (Ocimum basilicum L.) are used to prepare pesto sauce, a tasty condiment that attracts the interest of the food processing industry. Like other leafy or aromatic vegetables, basil is harvested more than once during the crop cycle to maximize yield. However, the mechanical stress induced by successive cuts can affect crucial parameters associated with pesto processing (leaf/stem ratio, stem diameter, and dry matter). Our research accordingly aimed to evaluate the impact of successive harvests on three field-grown Genovese basil cultivars (“Aroma 2”, “Eleonora” and “Italiano Classico”) in terms of production, physiological behavior, and technological parameters. Between the first and second harvest, marketable fresh yield and shoot dry biomass increased by 148.4% and 172.9%, respectively; by contrast, the leaf-to-stem ratio decreased by 22.5%, while the dry matter content was unchanged. The increased fresh yield and shoot dry biomass at the second harvest derived from improved photosynthetic efficiency, which enabled higher net CO2 assimilation, Fv/Fm and transpiration as well as reduced stomatal resistance. Our findings suggest that, under the Mediterranean environment, “Italiano Classico” carries superior productive performance and optimal technological characteristics in line with industrial requirements. These promising results warrant further investigation of the impact successive harvests may have on the qualitative components of high-yielding basil genotypes with respect to consumer expectations of the final product.

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The Impact of RDP Measures on the Diversification of Agriculture and Rural Development—Seeking Additional Livelihoods: The Case of Poland

Agriculture ◽

10.3390/agriculture11030253 ◽

2021 ◽

Vol 11 (3) ◽

pp. 253

Author(s):

Mirosław Biczkowski ◽

Aleksandra Jezierska-Thöle ◽

Roman Rudnicki

Keyword(s):

Rural Development ◽

Rural Areas ◽

Spatial Scales ◽

Development Program ◽

Spatial Diversity ◽

Agricultural Activities ◽

Synthetic Index ◽

Two Measures ◽

The Impact ◽

The Eu

The paper’s main aim is to assess the measures implemented within the Rural Development Program (RDP) 2007–2013 in Poland. This programme is dedicated to the diversification of business activities in rural areas and rural livelihood and, thus, the improvement of the multifunctionality of rural areas. The analysis covered two measures from Axis 3, Improvement of the quality of life in rural areas and diversification of rural economy: M311, diversification into non-agricultural activities; and M312, Establishment and development of micro-enterprise. The study and the discussion are presented from a geographical perspective and, in a broader context, take into account several conditions (natural, urban, agricultural and historical) and the spatial diversity of the allocation of European Union (EU) funds. Models of a policy of multifunctional rural development, implemented after accession to the EU, are presented. The research’s spatial scope covers Poland’s territory on two spatial scales: the system of regions (16 NUTS2 units) and poviats (314 LAU level 1 units). The analysis covers all the projects implemented in Poland under the two measures of Axis 3 of the RDP 2007–2013. A set of conditions was prepared for all LAU1 units, forming the background for assessing the impact of the EU funds on the development of non-agricultural activities. To determine the relationship between the RDP measures and the selected groups of conditions, a synthetic index and a correlation index are used. They are also used to determine the mutual relations between the two analyzed activities in terms of the spatial scales used. Access to the EU funds (RDP) has considerably enlarged the opportunities for accelerating agricultural modernisation and restructuration towards multifunctional development, as well as the opportunities for implementing new development and work methods in the countryside in Poland. The attractiveness of the two studied RDP measures varied across regions. The beneficiaries’ activity depended on the local potential (resources), culture and tradition of the region, and size and potential of the farm. In the areas where agriculture is deeply rooted, beneficiaries were more willing to engage in ventures tapping into the resources available in their farms. Thus, they create additional livelihood of income and workplaces for household members. In turn, the beneficiaries from the areas where farms are smaller and economically weaker often undertake activities related to setting up a new business (outside farming).

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