A woody plant community and tree-cacti associations change with distance to a water source in a dry Chaco forest of Argentina

2017 ◽  
Vol 39 (1) ◽  
pp. 15 ◽  
Author(s):  
Carolina B. Trigo ◽  
Andrés Tálamo ◽  
Mauricio M. Núñez-Regueiro ◽  
Enrique J. Derlindati ◽  
Gustavo A. Marás ◽  
...  

In semiarid regions, livestock is concentrated around water sources generating a piosphere pattern (gradients of woody vegetation degradation with increasing proximity to water). Close to the water source, livestock may affect the composition, structure and regeneration strategies of woody vegetation. We used the proximity from a water source as a proxy of grazing pressure. Our objectives were (1) to compare woody vegetation attributes (richness, diversity, species composition, density and basal area) and ground cover between sites at two distances to a water source: near (higher grazing pressure) and far from the water source (lower grazing pressure), and (2) to quantify and compare cases of spatial association among the columnar cacti Stetsonia coryne (Salm-Dyck) Britton and Rose (Cactaceae), and the dominant tree Bulnesia sarmientoi Lorentz ex Griseb. (Zygophyllaceae). We used a paired design with eight pairs of rectangular plots distributed along a large and representative natural water source. We found lower total species richness, plant density and soil cover near than far from water source, and more cases of spatial associations between the two species studied. Our results show evidence of increased livestock impacts around water sources. However, we found no difference in terms of species composition or basal area at near versus far sites. We conclude that grazing pressure might be changing some attributes of the woody plant community, and that the association of young trees with thorny plants (grazing refuge) could be a regeneration mechanism in this semiarid forest with high grazing pressure.

2018 ◽  
Vol 24 (1) ◽  
pp. 35
Author(s):  
Laurie Strommer ◽  
Sheila Conant

Efforts to restore forests for ecological and economic benefit in Hawaii are converging on koa (Acacia koa), an endemic dominant or codominant canopy tree common across broad elevation and moisture gradients. We quantified plant species composition and forest structure in koa reforestation areas (KRAs) and in nearby intact native forest on Hawaii Island. Total species richness and percentage native species richness were lower in the plantation forests than in the intact forests, although species richness in the KRAs at one site was not significantly different from that in intact forest. Tree, sapling, and seedling densities differed between KRAs and forest sites at one site. At another, the native forest and one KRA had similar tree and seedling densities and similar canopy height and percentage canopy cover. Total stand basal area was greatest in the intact forest at both sites, although the basal area for the KRAs at one site exceeded those for intact forest at the other. Koa plantings can be structurally similar to intact forests though species composition differs. Our results suggest that koa forestry can facilitate native understorey development in some cases.


2021 ◽  
Author(s):  
Erica McCormick ◽  
David Dralle ◽  
William Hahm ◽  
Alison Tune ◽  
Logan Schmidt ◽  
...  

Abstract Woody plant transpiration is a major control on Earth’s climate system, streamflow, and human water supply. Soils are widely considered to be the primary reservoir of water for woody plants, however, plants also access water stored in the fractures and pores of bedrock, either as rock moisture (water stored in the unsaturated zone) (Schwinning, 2010) or bedrock groundwater (below the water table) (Miller et al., 2010). Bedrock as a water source for plants has not been evaluated over large scales, and consequently, its importance to terrestrial water and carbon cycling is poorly known (Fan et al., 2019). Here, we show that woody plants routinely access significant quantities of water stored in bedrock —commonly as rock moisture —for transpiration across diverse climates and biomes. For example, in California, the volume of bedrock water transpired by woody vegetation annually exceeds that stored in man-made reservoirs, and woody vegetation that withdraws bedrock water accounts for over 50% of the aboveground carbon stocks in the state. Our findings show that bedrock water storage dynamics are a critical element of terrestrial water cycling and therefore necessary to capture the effect of shifting climate on woody ecosystems, above- and belowground carbon storage, and water resources.


Author(s):  
Nuru Mohammed

Aim: This study was conducted to assessing woody plant composition, population structure and regeneration status in lowland exclosure (EX) of Northern Ethiopia. Study Design: Investigation of parameters was undertaken from 71 plots with size of 20 m x 10 m laid systematically along transect lines for vegetation data. These 200 m2 plots were used for assessment of trees with DBH >5 cm. Small quadrats of 4 m*4 m (16 m2) nested within the bigger plots was laid at the four corners and center of each plots. These were used for measuring seedling and sapling individuals. To analyze species diversity, population structure and regeneration status of woody plants were by computing abundance, density, basal area, Importance value index (IVI) and using Shannon-Weiner diversity and evenness indices. Results: According to vegetation survey result, a total of 23, 17 and 26 woody species were recorded, at Kara, Erba and Shektekli exclosures (EXs), respectively. While 8, 7 and 5 species of woody plant were in open grazing land (OGL). The total mean densities of all woody plants were found to be 1530, 1480 and 2999 individual’s ha-1 at Kara, Erba and Shektekli in EXs. Conclusion: The study suggested that the regional government have to considering EXs as useful for restoration or rehabitation strategy in the region, the vegetation in all the EXs in the study sites have a higher species composition, diversity, density, increment of basal area and regeneration woody plants than OGL, as a result of management differences in EXs. However, there are also variation on species composition, diversity, density increment of basal area and regeneration woody plants among exclosures having similar age and altitude for instance the species recorded in Erba site is lower than with other of EXs, This could be due to among local site characteristic variation and high grazing happen before Ex establishment exists. Therefore, we need to apply soil and water conservation, enrichment planting with indigenous tree species and strengthen local management institution in effectively protect the exclosure.


Author(s):  
Ariyo, Oluyinka Christopher

Woody plants species composition, richness, dominance and diversity in west bank forest of International Institute of Tropical Agriculture (IITA) was undertaken to understand the status of the forest. The analysis of tree species composition, richness and diversity in the forest was carried out with the aim of developing efficient management plan that will ensure biodiversity conservation. Vegetation survey using transects and plot sampling techniques were used to collect data for the study. Three transects of 500 m long each {A (270°W), B (90°E) and C (180°S)} were constructed with the aid of prismatic compass in the forest. 10 sampling plots of 10 m by 10 m each were demarcated along each transect making a total number of 30 sampling plots. In each plot, all woody plant species (trees and shrubs) with girth at breast height (gbh) greater than or equal to 10 cm (gbh ≥ 10 cm) were identified, enumerated and measured. The results showed that 581 woody plants belonging to 65 species and 28 families were encountered in the forest. The most abundant family in the forest was Fabaceae sub families of Caesalpinioidea, Mimosoideae and Palpilinoideae. The forest had Simpson diversity index (D), Shannon-Wiener (H) and Evenness index of 0.012, 0.354 and 0.195 respectively. The total density and basal area of woody plants species in the forest was 1,936.67 individuals’ ha-1 and 98.23 m2 ha−1. Newbouldia laevis had the highest density of 190 ha-1 and relative frequency of 9.811% while Milicia excelsa had the highest basal area of 40.34 m2 ha−1, relative dominance of 41.07% and Importance value index of 14.04%. The study concludes that the forest has a reasonably good tree and shrub species composition and richness, dominated by trees and a repository of many indigenous tropical woody plant species. The study recommends in-depth forest inventory, preparation of management plan and promotion of good governance in management of the forest. Also, further studies on regeneration, structure, soil seed bank, seed physiology and herbaceous plant should be carried out in the forest.


Hoehnea ◽  
2011 ◽  
Vol 38 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Pedro Vasconcellos Eisenlohr ◽  
Maria Margarida da Rocha Fiuza de Melo ◽  
Mariana Rodrigues da Silva ◽  
Philippe Schmal ◽  
Walnir Gomes Ferreira-Júnior ◽  
...  

The opening and use of a trail can modify abiotic factors along its route and in the closer surroundings. These changes can be verified by floristic changes of vegetation. This study evaluated a possible influence of a trail on the woody vegetation (DBH ³ 2.5 cm, except lianas) in a Semideciduous Seasonal Forest in Viçosa, Minas Gerais State, Brazil (20º45'S and 42º51'W). Ten plots were sampled in an area near a trail and 10 other plots in the forest interior, totaling 718 individuals. Cluster (WPGMA) and ordination (DCA) analysis suggest that it may be a certain degree of influence of the trail on vegetation, although some results were intriguing. Further studies may be added to this in order to establish, in the future, environmental policies that take this source of interference with native ecosystems into account.


Hydrology ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 40 ◽  
Author(s):  
Md. Shawkat I. Sohel ◽  
Mohammed Abdus Salam ◽  
John Herbohn

In the face of global climate change, water availability and its impact on forest productivity is becoming an increasingly important issue. It is therefore necessary to evaluate the advancement of research in this field and to set new research priorities. A systematic literature review was performed to evaluate the spatiotemporal dynamics of global research on woody plant water sources and to determine a future research agenda. Most of the reviewed studies were from the United States, followed by China and Australia. The research indicates that there is a clear variation in woody plant water sources in forests due to season, climate, leaf phenology, and method of measurement. Much of the research focus has been on identifying plant water sources using a single isotope approach. Much less focus has been given to the nexus between water source and tree size, tree growth, drought, water use efficiency, agroforestry systems, groundwater interactions, and many other topics. Therefore, a new set of research priorities has been proposed that will address these gaps under different vegetation and climate conditions. Once these issues are resolved, the research can inform forest process studies in new ways.


Rodriguésia ◽  
2016 ◽  
Vol 67 (4) ◽  
pp. 859-870 ◽  
Author(s):  
Letícia Gomes ◽  
Leandro Maracahipes ◽  
Simone Matias Reis ◽  
Beatriz Schwantes Marimon ◽  
Ben Hur Marimon-Junior ◽  
...  

Abstract Differences in substrates can provoke distinct responses in the dynamics of a plant community. We compared changes the floristic, structural and dynamic parameters of the woody vegetation between burned sites dominated by cerrado típico (CT) and cerrado rupestre (CR), which is characterized by the presence of rocky outcrops, over time. We set up 10 plots (20 m × 50 m) at each site. All individuals (diameter of ≥ 3 cm at 30 cm height above the ground) were identified in the two censuses (2009 and 2012) and measured (stem diameter), after an accidental fire in 2008. Changes in floristic parameters between the CT and CR were not significant. However, we found significant differences (p < 0.05) in structural and dynamic parameters, such as density (CT = 1,523; CR = 2,171 ind.ha-1), basal area (CT = 8.70; CR = 13.00 m2.ha-1), recruitment rates (CT = 24.35; CR = 15.14% year-1; p = 0.01), gain (CT = 8.58; CR= 3.58% year-1), and the loss rates of basal area (CT = 3.88; CR= 2.45% year-1). These differences emphasize the need for a differential evaluation of these sites for the development of effective conservation strategies.


Author(s):  
Alexey Shcherbakov ◽  
Valentin Zhezmer

Department of hydraulic engineering and hydraulics FGBNU «VNIIGiM them. A.N. Kostyakova «has a long history. For many years, the department’s staff has been such scientists and water engineers with extensive experience as M.A. Volynov, V.S. Verbitsky, S.S. Medvedev, N.V. Lebedev, B.C. Panfilov, T.G. Voynich-Syanozhentsky, V.A. Golubkova, G.V. Lyapin and others. The department solved a wide range of tasks, the main areas of research were the following: – theoretical and applied hydrodynamics and hydraulics, with reference to the open channel flows that affect the state and level of safety of the hydraulic structures; – integrated use and protection of water bodies – water sources and water sources of water resources used in land reclamation; – development of measures and technical solutions for the protection of objects from the negative effects of water; – theoretical substantiation of works to improve the safety level of the GTS (declaration); – development and implementation of digitalization methods for solving design, construction, operation and control of landreclamation facilities. Currently, promising areas of research is the development of a decision-making algorithm in the designation of measures to rationalize the provision of resources to water amelioration. The algorithm is developed on the basis of a detailed study, systematization and processing of data both on safety and on the efficiency of systems and structures, ensuring the delivery of irrigation water of the required quality and in sufficient quantity from a water source to the field.


1995 ◽  
Vol 32 (4) ◽  
pp. 187-196 ◽  
Author(s):  
L. Pechar

The study presents data on the species composition of cyanobacterial water blooms in Czech fish ponds from the 1950s to the 1990s. Since the 1950s, a shift from large-colonial Aphanizomenon flos-aquae var. flos-aquae through Microcystis aeruginosa and small-colonial species of Anabaena to single-filament species (Planktohrix agardhii, Limnothrix redekei, Aphanizomenon gracile) or single-cell forms (Microcystis ichtyoblabe), has been observed. The changes in the species composition of the water blooms are closely related to changes in fishery management (increase in fish stock, increase in application of organic fertilizers). At present the high predation of fish upon zooplankton results in elimination of large colonial blooms of A. flos-aquae associated with large filtering zooplankton (Daphnia). Low grazing pressure of zooplankton, low light conditions and low N:P ratios are suitable conditions for mass development of the small species of cyanobacteria. High pH is not necessary to achieve cyanobacteria dominance.


1999 ◽  
Vol 64 ◽  
Author(s):  
D. Van den Meersschaut ◽  
B. De Cuyper ◽  
K. Vandekerkhove ◽  
N. Lust

Natural  stand changes in the forest reserve of Liedekerke were analysed during the  period    1986-1996, using a permanent grid of circular plots. The monitoring  concentrated on natural    changes in species composition, using stem number and basal area as  indicators, and changes    in spatial distribution and colonization capacities of trees and shrubs,  with special interest in the    competition between exotic and indigenous species. After only a decade of  monitoring important    natural changes in the woody layer were detected. The pioneer forest is  gradually maturing    through self-thinning processes and shifts in species composition. The  overall stem number    decreased with 33.6%, while the basal area increased with 20.9%. Birch (Betula pendula/    pubescens) and indigenous oak (Quercus robur/petraea) remained  dominant. More tolerant    exotic species, like red oak (Quercus rubra) and sweet chestnut (Castanea  sativa), are slowly    increasing their share in the species composition and expanding their  range. Pioneer species on    the other hand, like aspen (Populus tremula), willow (Salix  capreaicinerealaurita), alder buckthorn    (Frangula alnus) and  common (Alnus glutinosa)  and grey alder (A. incana),  strongly declined.    Black cherry (Prunus serotina) seems to be slowly invading the forest due to its  massive    natural regeneration. Strong competition may be expected especially from  rowan ash (Sorbus    aucuparia), which showed similar regeneration  and colonization capacities. Elder (Sambucus    nigra) dramatically extented its range, though  its share remains marginal. Beech remained absent    most probably due to the lack of mature trees in the vacinity of the  forest. Finally this    change detection allowed that general predictions could be made on the  future natural development    and composition of this forest reserve, which could serve forest management  decisions.


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