The structural complexity index SCI is useful for quantifying structural diversity of Estonian hemiboreal forests

2021 ◽  
Vol 490 ◽  
pp. 119093
Author(s):  
Eneli Põldveer ◽  
Aleksei Potapov ◽  
Henn Korjus ◽  
Andres Kiviste ◽  
John A. Stanturf ◽  
...  
Keyword(s):  
Structural Complexity ◽  
Structural Diversity ◽  
Complexity Index

The effect of prey availability on spider assemblages on European black pine (Pinus nigra) bark: spatial patterns and guild structure

2005 ◽  
Vol 83 (2) ◽  
pp. 324-335 ◽  
Author(s):  
Roland Horváth ◽  
Szabolcs Lengyel ◽  
Csaba Szinetár ◽  
László Jakab
Keyword(s):  
Species Richness ◽  
Prey Availability ◽  
Negative Relationship ◽  
Structural Complexity ◽  
Structural Diversity ◽  
Pinus Nigra ◽  
Black Pine ◽  
Number Of Individuals ◽  
Negative Relationships ◽  
European Black Pine

Both habitat structural complexity and prey availability can influence the density and diversity of spider assemblages. We studied whether prey availability affects spider assemblages living on the bark of European black pine (Pinus nigra Arnold) in six localities in Hungary. We found both positive and negative relationships between spider and prey assemblages in a sample of 1290 spiders and 24 186 potential prey when among-locality variation in spider assemblages was controlled for. Species richness, number of individuals, and diversity of spiders increased with either the number of prey taxa or the number of prey individuals in a forest in western Hungary. Spider species richness and number of individuals increased with prey diversity but decreased with number of prey taxa in moderately air-polluted urban localities. There was a negative relationship between number of spider individuals and number of prey individuals in a heavily polluted urban locality. Numbers of nocturnal hunters but not diurnal hunters or web-builders increased with the number of their respective prey in the forest in western Hungary and in the moderately air-polluted urban localities. The number of exclusive bark-dwelling spiders increased with the number of prey individuals in forests in eastern Hungary and decreased with the number of prey individuals in the polluted urban locality. We suggest that patterns of spider assemblages can be influenced by prey availability and that other factors (e.g., habitat structural diversity and air pollution) also need to be considered in explaining these patterns.

scholarly journals Enhanced Structural Complexity Index: An Improved Index for Describing Forest Structural Complexity

2013 ◽  
Vol 03 (01) ◽  
pp. 23-29 ◽  
Author(s):  
Philip Beckschäfer ◽  
Philip Mundhenk ◽  
Christoph Kleinn ◽  
Yinqiu Ji ◽  
Douglas W. Yu ◽  
...  
Keyword(s):  
Structural Complexity ◽  
Complexity Index

Ascidian halogen-containing secondary metabolites from the family didemnidae

2019 ◽  
Vol 17 (2) ◽  
pp. 97-130
Author(s):  
Miljana Djordjevic ◽  
Niko Radulovic
Keyword(s):  
Secondary Metabolites ◽  
Total Synthesis ◽  
Current Knowledge ◽  
Structural Complexity ◽  
Structural Diversity ◽  
Pharmacological Properties ◽  
Pharmacological Activities ◽  
The Family ◽  
Biological Tests ◽  
Brominated Compounds

This review summarizes current knowledge concerning the isolation, structural elucidation, biological/pharmacological activities, and total synthesis of halogen-containing secondary metabolites isolated from ascidians of the family Didemnidae. Overall, 81 compounds are presented, displaying great structural diversity and possessing a number of significant biological/pharmacological properties. In addition to the most numerous brominated compounds, chlorinated and iodinated ones were also found. The most prolific genus in regard to the number of published papers and isolated molecules is the genus Didemnum, which was treated separately from the rest of the genera of the ascidian family. The structural complexity of the isolated metabolites prompted a number of synthetic endeavors that not only provided conclusive proof of the structure of the metabolites but also enabled the biological tests and the possible application of these metabolites.

scholarly journals Enhancer hijacking determines extrachromosomal circular MYCN amplicon architecture in neuroblastoma

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Konstantin Helmsauer ◽  
Maria E. Valieva ◽  
Salaheddine Ali ◽  
Rocío Chamorro González ◽  
Robert Schöpflin ◽  
...  
Keyword(s):  
Structural Complexity ◽  
Structural Diversity ◽  
Regulatory Elements ◽  
Regulatory Requirements ◽  
Circular Dna ◽  
Regulatory Circuit ◽  
Gene Copies ◽  
Gene Regulatory Elements ◽  
Gene Regulatory ◽  
Functional Relevance

AbstractMYCN amplification drives one in six cases of neuroblastoma. The supernumerary gene copies are commonly found on highly rearranged, extrachromosomal circular DNA (ecDNA). The exact amplicon structure has not been described thus far and the functional relevance of its rearrangements is unknown. Here, we analyze the MYCN amplicon structure using short-read and Nanopore sequencing and its chromatin landscape using ChIP-seq, ATAC-seq and Hi-C. This reveals two distinct classes of amplicons which explain the regulatory requirements for MYCN overexpression. The first class always co-amplifies a proximal enhancer driven by the noradrenergic core regulatory circuit (CRC). The second class of MYCN amplicons is characterized by high structural complexity, lacks key local enhancers, and instead contains distal chromosomal fragments harboring CRC-driven enhancers. Thus, ectopic enhancer hijacking can compensate for the loss of local gene regulatory elements and explains a large component of the structural diversity observed in MYCN amplification.

scholarly journals A simple and effective approach to quantitatively characterize structural complexity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gongqiao Zhang ◽  
Gangying Hui ◽  
Aiming Yang ◽  
Zhonghua Zhao
Keyword(s):  
Structural Complexity ◽  
Basal Area ◽  
Structural Diversity ◽  
Distribution Patterns ◽  
Natural Forest ◽  
Random Trees ◽  
Forest Communities ◽  
Natural Forests ◽  
Planted Forests ◽  
Structural Units

AbstractThis study brings insight into interpreting forest structural diversity and explore the classification of individuals according to the distribution of the neighbours in natural forests. Natural forest communities with different latitudes and distribution patterns in China were used. Each tree and its nearest neighbours form a structural unit. Random structural units (or random trees) in natural forests were divided into different sub-types based on the uniform angle index (W). The proportions of different random structural units were analysed. (1) There are only two types of random structural units: type R1 looks similar to a dumbbell, and type R2 looks similar to a torch. These two random structural units coexist in natural forests simultaneously. (2) The proportion of type R1 is far less than that of R2, is only approximately 1/3 of all random structural units or random trees; R2 accounts for approximately 2/3. Furthermore, the proportion of basal area presents the same trend for both random structural units and random trees. R2 has approximately twice the basal area of R1. Random trees (structural units) occupy the largest part of natural forest communities in terms of quantity and basal area. Meanwhile, type R2 is the largest part of random trees (structural units). This study finds that the spatial formation mechanism of natural forest communities which is of great significance to the cultivation of planted forests.

Structurally complex, yet anatomically plesiomorphic: permineralized plants from the Emsian of Gaspé (Quebec, Canada) expand the diversity of Early Devonian euphyllophytes

IAWA Journal ◽  
2019 ◽  
Vol 40 (3) ◽  
pp. 421-445 ◽  
Author(s):  
Maya A. Bickner ◽  
Alexandru M. F. Tomescu
Keyword(s):  
Secondary Growth ◽  
Central Area ◽  
Structural Complexity ◽  
Structural Diversity ◽  
Late Devonian ◽  
Histological Differentiation ◽  
Eastern Canada ◽  
Early Devonian ◽  
Growth Initiation ◽  
P Type

ABSTRACTThe Battery Point Formation of eastern Canada hosts an Emsian (c. 400–395 Ma) flora that marks one of the rare occurrences of anatomically-preserved Early Devonian plants. We describe four new euphyllophytes from small permineralized axes in this unit. Leptocentroxyla tetrarcha gen. et sp. nov. has a four-ribbed mesarch actinostele with Psilophyton-type (P-type) tracheids and a central area of scalariform tracheids. Stenoloboxyla ambigua gen. et sp. nov. has a bar-shaped to three-ribbed mesarch stele lacking central protoxylem, with one of the ribs less pronounced, P-type tracheids, and sclerenchyma forming a discontinuous layer in the cortex. Jowingera triloba gen. et sp. nov. has a three-ribbed mesarch actinostele with central protoxylem and P-type tracheids. Tainioxyla quebecana gen. et sp. nov. has bar-shaped xylem with mesarch protoxylem strands, P-type tracheids, and anatomy typical of cambial growth initiation. These new species raise the diversity of Battery Point Formation permineralized plants to nine genera, adding significantly to the diversity of Early Devonian plants characterized anatomically. The four species encompass structural diversity of unexpected breadth and novelty for their age. They are different from both older and coeval euphyllophytes and from younger euphyllophytes, exhibiting combinations of derived and plesiomorphic characters. Their mesarch actinosteles and barshaped protosteles, histological differentiation within metaxylem and cortex, and secondary growth, represent aspects of structural complexity common in more derived Middle-Late Devonian euphyllophytes. Concurrently, the four species share P-type tracheids typical of Early Devonian basal euphyllophytes with simpler anatomies. These new fossils offer a first glimpse of a plexus of plants representing a previously unsuspected stage of euphyllophyte morphoanatomical evolution. They demonstrate significant euphyllophyte diversification and exploration of structural complexity under way during the Early Devonian, against a background of plesiomorphic-type tracheids. When more completely characterized, these Emsian plants will provide links for resolving phylogenetic relationships at the base of the euphyllophyte clade.

Response of small mammals to alternative stand structures in the mixed-conifer forest of northeastern CaliforniaThis article is one of a selection of papers from the Special Forum on Ecological Studies in Interior Ponderosa Pine — First Findings from Blacks Mountain Interdisciplinary Research.

2008 ◽  
Vol 38 (5) ◽  
pp. 943-955 ◽  
Author(s):  
Chris C. Maguire ◽  
Douglas A. Maguire ◽  
Tom E. Manning ◽  
Sean M. Garber ◽  
Martin W. Ritchie
Keyword(s):  
Small Mammals ◽  
Ponderosa Pine ◽  
Structural Complexity ◽  
Basal Area ◽  
Stand Density ◽  
Structural Diversity ◽  
Conifer Forest ◽  
Spermophilus Lateralis ◽  
Mixed Conifer Forest ◽  
Tamias Amoenus

A common, but largely untested, strategy for maintaining forest biodiversity is to enhance stand structural complexity. A silvicultural experiment was implemented from 1996 to 1998 at Blacks Mountain Experimental Forest, California, to test the efficacy of two levels of structural diversity (high versus low) and two levels of prescribed underburning (burn versus no burn) for maintaining or restoring biodiversity. Small mammals were trapped and tagged in experimental units for 2 noncontiguous weeks in fall 2003 and 2004. Total number of captures and number of captured individuals varied by year (P < 0.002). No treatment effects were detected for all species lumped together or for the three most frequent species analyzed separately ( Tamias amoenus J.A. Allen, 1890, Peromyscus maniculatus (Wagner, 1845), and Spermophilus lateralis (Say, 1823)), with the exception that T. amoenus was captured more often in burned units in 2004 (P = 0.004 for year × burn interaction). Mixed-effects regression models indicated that the number of captures and captured individuals of T. amoenus and P. maniculatus decreased with increasing residual basal area of overstory trees, but opposite results were obtained for S. lateralis. After accounting for residual stand density differences, T. amoenus was captured more frequently in units of low structural diversity and S. lateralis in units of high structural diversity.

Development of a forest structural complexity index based on multispectral airborne remote sensing and topographic dataThis article is one of a selection of papers from Extending Forest Inventory and Monitoring over Space and Time.

2011 ◽  
Vol 41 (1) ◽  
pp. 44-58 ◽  
Author(s):  
Jon Pasher ◽  
Douglas J. King
Keyword(s):  
Remote Sensing ◽  
Redundancy Analysis ◽  
Mean Squared Error ◽  
Multiple Scales ◽  
Structural Parameters ◽  
Structural Complexity ◽  
Tree Height ◽  
Area Index ◽  
Complexity Index ◽  
Structural Variables

This paper presents development of a multivariate forest structural complexity index based on relationships between field-based structural variables and geospatial data. Remote sensing has been widely used to model individual forest structural attributes at many scales. As opposed to, or in addition to, individual structural parameters such as leaf area index or tree height, overall structural complexity information can enhance forest inventories and provide a variety of information to forest managers, including identifying damage and disturbance as well as indicators of habitat or biodiversity. In this study, a multivariate modelling technique, redundancy analysis, was implemented to derive a model incorporating both horizontal and vertical structural attributes as predicted by an ensemble of high-resolution multispectral airborne imagery and topographic variables. The first redundancy analysis axis of the final model explained 35% of the total variance of the field variables and was used as the complexity index. With a root mean squared error of 19.9%, the model was capable of differentiating four to five relative levels of complexity. This paper presents the forest ecological and modelling aspects of the research. A related paper presents the remote sensing aspects, including application of the model to map predicted structural complexity, map validation, and testing of the method at multiple scales.

scholarly journals Same Viewpoint Different Perspectives—A Comparison of Expert Ratings with a TLS Derived Forest Stand Structural Complexity Index

2019 ◽  
Vol 11 (9) ◽  
pp. 1137 ◽  
Author(s):  
Julian Frey ◽  
Bettina Joa ◽  
Ulrich Schraml ◽  
Barbara Koch
Keyword(s):  
Forest Structure ◽  
Laser Scanning ◽  
Online Survey ◽  
Structural Complexity ◽  
Terrestrial Ecosystems ◽  
Linear Mixed Effect Model ◽  
Mixed Effect ◽  
Complexity Index ◽  
Retention Forestry ◽  
Expert Ratings

Forests are one of the most important terrestrial ecosystems for the protection of biodiversity, but at the same time they are under heavy production pressures. In many cases, management optimized for timber production leads to a simplification of forest structures, which is associated with species loss. In recent decades, the concept of retention forestry has been implemented in many parts of the world to mitigate this loss, by increasing structure in managed stands. Although this concept is widely adapted, our understanding what forest structure is and how to reliably measure and quantify it is still lacking. Thus, more insights into the assessment of biodiversity-relevant structures are needed, when aiming to implement retention practices in forest management to reach ambitious conservation goals. In this study we compare expert ratings on forest structural richness with a modern light detection and ranging (LiDAR) -based index, based on 52 research sites, where terrestrial laser scanning (TLS) data and 360° photos have been taken. Using an online survey (n = 444) with interactive 360° panoramic image viewers, we sought to investigate expert opinions on forest structure and learn to what degree measures of structure from terrestrial laser scans mirror experts’ estimates. We found that the experts’ ratings have large standard deviance and therefore little agreement. Nevertheless, when averaging the large number of participants, they distinguish stands according to their structural richness significantly. The stand structural complexity index (SSCI) was computed for each site from the LiDAR scan data, and this was shown to reflect some of the variation of expert ratings (p = 0.02). Together with covariates describing participants’ personal background, image properties and terrain variables, we reached a conditional R2 of 0.44 using a linear mixed effect model. The education of the participants had no influence on their ratings, but practical experience showed a clear effect. Because the SSCI and expert opinion align to a significant degree, we conclude that the SSCI is a valuable tool to support forest managers in the selection of retention patches.

scholarly journals Enhancer hijacking determines intra- and extrachromosomal circular MYCN amplicon architecture in neuroblastoma

2019 ◽  
Author(s):  
Konstantin Helmsauer ◽  
Maria Valieva ◽  
Salaheddine Ali ◽  
Rocio Chamorro Gonzalez ◽  
Robert Schöpflin ◽  
...  
Keyword(s):  
Structural Complexity ◽  
Structural Diversity ◽  
Regulatory Elements ◽  
Regulatory Requirements ◽  
Circular Dna ◽  
Regulatory Circuit ◽  
Gene Copies ◽  
Gene Regulatory Elements ◽  
Gene Regulatory ◽  
Functional Relevance

AbstractMYCN amplification drives one in six cases of neuroblastoma. The supernumerary gene copies are commonly found on highly rearranged, extrachromosomal circular DNA. The exact amplicon structure has not been described thus far and the functional relevance of its rearrangements is unknown. Here, we analyzed the MYCN amplicon structure and its chromatin landscape. This revealed two distinct classes of amplicons which explain the regulatory requirements for MYCN overexpression. The first class always co-amplified a proximal enhancer driven by the noradrenergic core regulatory circuit (CRC). The second class of MYCN amplicons was characterized by high structural complexity, lacked key local enhancers, and instead contained distal chromosomal fragments, which harbored CRC-driven enhancers. Thus, ectopic enhancer hijacking can compensate for the loss of local gene regulatory elements and explains a large component of the structural diversity observed in MYCN amplification.

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