Successional and mature stands in an upper Andean rain forest transect of Venezuela: do leaf characteristics of woody species differ?

2003 ◽  
Vol 19 (3) ◽  
pp. 251-259 ◽  
Author(s):  
Julio V. Schneider ◽  
Daniela Zipp ◽  
Juan Gaviria ◽  
Georg Zizka

Changes in morphological and anatomical leaf characteristics of woody plant species along an altitudinal gradient as well as between a late-successional and mature upper montane rain forest were examined. For leaf size, the Raunkiaer-Webb classification system was applied. The mature-forest transect comprised eight plots of 0.1 ha between 2300 and 3300 m asl, the successional-forest transect, four plots between 2400 and 2750 m asl. The latter comprised structurally heterogeneous vegetation patches. For each plot the proportions of leaf size classes and of the different categories of leaf shape, margin, and apex were calculated. Leaf size and the proportion of drip-tips decreased with increasing elevation. Serrate leaf margins were more prominent at higher elevations. Stomatal density, leaf thickness and related anatomical characteristics did not show significant trends. Differences between the mature and successional forest plots were generally slight. The advanced age of the successional forest probably led to a convergent development of leaf characteristics.

2006 ◽  
Vol 49 (6) ◽  
pp. 953-965 ◽  
Author(s):  
Renato A. Ferreira de Lima ◽  
Leila Cunha de Moura

In the Atlantic Montane Rain Forest of South-eastern Brazil, a study was carried out to describe and evaluate canopy gap colonization. Gap composition by herb species was assessed through their soil coverage and woody species by measuring and identifying all individuals taller than one meter. Gap structure (gap size, number and diameter of treefalls), topographic position and surrounding vegetation were also measured. Two genera of Marantaceae were markedly frequent and abundant inside gaps. The more abundant and frequent woody species were shade tolerant. Species-rich families found inside gaps did not differ from the forest as a whole. Results revealed that direct and indirect influences of topography were important to determine gap composition of woody species. Evidently gap colonization had a considerable influence of topography and pre-established individuals besides variables of gap structure.


2017 ◽  
Vol 51 ◽  
pp. 242-250
Author(s):  
M. V. Dulin

Tetralophozia setiformis is a widespread species occurring usually without organs of sexual and asexual reproduction. Gemmae of Tetralophozia setiformis were observed for the second time in Russia and Eurasia in the Northern Urals, Komi Republic. They form compact masses over upper leaves. The compact masses consist largely (70 %) of immature gemmae. Description of gemmae and gemmiparous shoots from the Northern Urals and their comparison with those from the other known localities, namely British Columbia (Canada) and the Murmansk Region (European Russia) were carried out. The gemmiparous plants of T. setiformis from the Northern Urals have approximately the same width as plants without gemmae but they are shorter. The leaves of gemmiparous plants from the Northern Urals are similar to leaves of gemmiparous plants from British Columbia. The leaf shape in upper part of the gemmiparous shoots varies from the typical to ± modified from gemmae production. These leaf shape transitions include reduction of leaf size and lobe number from 4 to 2–3, suppression of development and disappearance of characteristic teeth at the base of sinus. Gemmae size (17 × 22 μm) of plants from the Northern Urals is within variability recorded for plants from the Murmansk Region and British Columbia.


1996 ◽  
Vol 351 (1348) ◽  
pp. 1671-1677 ◽  

Leaves display an enormous array of sizes and shapes. Although these attributes appear to have evolved primarily in response to abiotic conditions in the plant’s habitat, the importance of insect herbivores as additional selective agents is still poorly understood. A necessary requirem ent for leaf size and shape to evolve in response to attack by insects is that insects must respond to and/or be affected by, leaf morphology. We tested leaf-shape preferences in adult flea beetles ( Phyllotreta spp.) feeding on the highly variable rosette leaves of Capsella bursa-pastoris . Contrary to theoretical expectation (Brown & Lawton 1991), leaves with deeply lobed margins were more intensely damaged, both in field-collected and experimental plants. In two ancillary experiments with Capsella , we found that Spodoptera caterpillars showed no preferences for leaf shape, but that adult vine weevils ( Otiorhynchus sulcatus ) did, preferring (as predicted), undivided over divided leaves. We conclude that Brown & Law ton’s (1991) hypothesis is at best weakly supported by laboratory data for vine weevils, refuted by laboratory data for Spodoptera , and consistently refuted by both laboratory and field data for flea beetles. Although the experiment tried to reduce confounding variables to a minimum, interpretation was complicated by correlations between leaf shape and other developmental parameters of the plants, and highlights the difficulty of disentangling leaf-shape effects from other confounding factors.


Phytotaxa ◽  
2017 ◽  
Vol 317 (4) ◽  
pp. 292 ◽  
Author(s):  
JULIO ANTONIO LOMBARDI ◽  
MARCELA SERNA GONZÁLEZ

A new South American species of Salacia (Celastraceae, Salacioideae) found in Colombia and Venezuela, Salacia fugax Lombardi & M.Serna is described here. It is characterized by its indument, small long acuminate leaves with short petioles, branched inflorescences, flowers with an annular-pulvinate disk, and small pyriform fruits. This new species resembles S. mennegana J.Hedin ex Lombardi and S. opacifolia (J.F.Macbr.) A.C.Sm. by its short petioles, leaf shape, slender branched inflorescence, perianth form, and similar disc, but S. fugax differs by its hairs, leaf size and apex, calyx, and fruit size and shape.


Phytotaxa ◽  
2014 ◽  
Vol 183 (2) ◽  
pp. 61 ◽  
Author(s):  
Kelly Cristina Silva-Gonçalves ◽  
José Fernando Andrade Baumgratz ◽  
André Felippe Nunes-Freitas

The Marambaia is an important natural refuge for preserving the genetic heritage of several rain forest plant species. In this insular region, where the vegetation types are Lower Montane Rain Forest and restingas (sandy coastal plain habitat), the impressive diversity of Melastomataceae consists of seven genera and 25 species of which 13 represent new records for the area. Miconia is best represented with 10 species, followed by Tibouchina (6 spp.), Leandra (4 spp.), Clidemia (2 spp.) and Huberia, Marcetia and Ossaea (1 sp. each). Most of the species are shrubs or trees and occur in Dense Submontane Ombrophilous Forest. Huberia ovalifolia DC., Leandra acutiflora (Naudin) Cogn. and Leandra melastomoides Raddi are cited in the list of endangered species for the municipality of Rio de Janeiro. An identification key is provided as well as descriptions, illustrations, comments on morphological peculiarities of species, and geographical and phenological data.


2019 ◽  
Vol 14 (3) ◽  
pp. 17-24
Author(s):  
D. M. Anatov ◽  
Z. M. Аsadulaev ◽  
R. M. Osmanov ◽  
K. I. Akhmedova

Aim. The paper presents the results of assessment of the indigenous nature and  degree of similarity of apricot cultivars growing in the collection of the Mountain  Botanical Garden, Gunib, Dagestan, Russia based on a comparative analysis of the  variability of leaf morphological characteristics.   Material and Methods. The material assessed consisted of 33 apricot cultivars of  various ecological and geographical origins aggregated in the following groups: (a)  Dagestan – traditional cultivars; (b) Moscow ‐ selection from the Tsytsin Main Moscow Botanical Garden, Russian Academy of Sciences based on wild forms of Tajikistan and Kyrgyzstan; (c) European and (d) Asian ‐ from Central Asia, Tajikistan, China  and Altai.   Results. The closeness of Dagestan and European varieties in comparison with Asian  and Moscow varieties was shown. Most Dagestan (16 of 19) and European varieties  have round‐shaped leaves (leaf shape index 80‐ 100%), while those from Asia and  the Moscow Botanical Garden have leaves which are elongated elliptical and oval  (60‐80%). Using the method of principal component analysis (PCA), it was established that most cultivars of Dagestan origin have similar leaf shapes and sizes, of  which Tlama kurak (wide‐round), Hekobarsh (elongated) were distinguished by leaf  shape and Esdelik by leaf size.   Conclusion. Based on a discriminant analysis (Squared Mahalanobis Distances), it  was found that the indices of indicators of leaf attributes (width/length of leaf lamina; petiole length/length of lamina; apex angle/corner of leaf base) are more reliable criteria for differentiating apricot varieties into ecological and geographical  groups than their morphological characteristics.  


Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 176
Author(s):  
István Fehérváry ◽  
Tímea Kiss

The most crucial function of lowland-confined floodplains with low slopes is to support flood conveyance and fasten floods; however, obstacles can hinder it. The management of riparian vegetation is often neglected, though woody species increase the vegetation roughness of floodplains and increase flood levels. The aims are (1) to determine the branch density of various riparian vegetation types in the flood conveyance zone up to the level of artificial levees (up to 5 m), and (2) to assess the spatial distribution of densely vegetated patches. Applying a decision tree and machine learning, six vegetation types were identified with an accuracy of 83%. The vegetation density was determined within each type by applying the normalized relative point density (NRD) method. Besides, vegetation density was calculated in each submerged vegetation zone (1–2 m, 2–3 m, etc.). Thus, the obstacles for floods with various frequencies were mapped. In the study area, young poplar plantations offer the most favorable flood conveyance conditions, whereas invasive Amorpha thickets and the dense stands of native willow forests provide the worst conditions for flood conveyance. Dense and very dense vegetation patches are common in all submerged vegetation zones; thus, vegetation could heavily influence floods.


2008 ◽  
Vol 102 (4) ◽  
pp. 623-629 ◽  
Author(s):  
Dongmei Yang ◽  
Guoyong Li ◽  
Shucun Sun
Keyword(s):  

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