scholarly journals Effect of Predation, Competition, and Facilitation on Tree Survival and Growth in Abandoned Fields: Towards Precision Restoration

Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 692 ◽  
Author(s):  
Annick St-Denis ◽  
Daniel Kneeshaw ◽  
Christian Messier

Tree seedlings planted in abandoned agricultural fields interact with herb communities through competition, tolerance, and facilitation. In addition, they are subject to herbivory by small mammals, deer or invertebrates. To increase the success of forest restoration in abandoned fields and reduce management costs, we should determine which species are tolerant to or facilitated by herbaceous vegetation and those which require protection from competition and predation. Eight native tree species were planted in plots covered by herbaceous vegetation, plots where herbaceous vegetation was removed, and plots where seedlings were surrounded by an organic mulch mat. Half of the seedlings were protected against small mammal damage. Results showed that two non-pioneer and moderately shade-tolerant species (yellow birch and red oak) were inhibited by herbaceous vegetation. Birch species were particularly affected by small mammal predation. No effects of predation or herbaceous competition were observed for conifer species. Rather, herbaceous vegetation had a positive effect on the survival and the height growth of tamarack (Larix laricina). None of the tested herb communities had a stronger competitive effect on tree growth than another. Restoration of abandoned fields using multi-tree species should be designed at the seedling scale rather than at the site scale to account for different tree responses to predation and competition as well as variable site conditions. An approach resembling precision agriculture is proposed to lower costs and any potential negative impact of more intensive vegetation management interventions.

2020 ◽  
Vol 68 (S1) ◽  
pp. S103-S114
Author(s):  
Luis Acosta-Vargas ◽  
Adriana E. Rovere ◽  
Jorge Camacho-Sandoval

Introduction: Isla del Coco is the only island in the Eastern Tropical Pacific with humid tropical forests; 296 plant species are reported, of them, 22% are endemic. Their ecology is poorly understood. Deforestation and the introduction of rats, feral pigs and white-tailed deer are the primary agents of forest degradation. After more than 120 years, the deforested areas have never recovered the native forest. Objective: To analyse if the deforested area keeps its resilience, we evaluated the natural regeneration and ecological processes associated. Methods: From August 2016 to June 2018, we conducted a restoration experiment consisting of a randomized complete blocks design including vegetation cutting, vegetation uprooting and controls as treatments. Plots were protected with an exclusion fence to avoid herbivores. Results: There were no differences between plant cutting and uprooting in stimulating natural regeneration. We only recorded the seedlings of two tree species, 35 individuals of Cecropia pittieri and three of Sacoglottis holdridgei, both endemic. Their regeneration established during the first 15 months mainly. At the end of the experiment, the structure and composition of the vegetation changed from bushes dominated by Entada gigas (28%) and Clidemia strigillosa (12%) to grasses dominated by Paspalum conjugatum (39%). Entada gigas has a high recolonizing potential with a growing rate of 1.6±0.2m/month. Conclusions: As filters for restoration we determined herbivores, which pose a strong negative impact in the development of the forest; the exhausted seed bank of tree species and scarce or null seed dispersion.


Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 458
Author(s):  
Haiyan Deng ◽  
Linlin Shen ◽  
Jiaqi Yang ◽  
Xiaoyong Mo

Background and Objectives: The stable stand structure of mixed plantations is the basis of giving full play to forest ecological function and benefit. However, the monocultural Eucalyptus plantations with large-scale and successive planting that caused ecological problems such as reduced species diversity and loss of soil nutrients have presented to be unstable and vulnerable, especially in typhoon-prone areas. The objective of this study was to evaluate the nonspatial structure difference and the stand stability of pure and mixed-Eucalyptus forests, to find out the best mixed pattern of Eucalyptus forests with the most stability in typhoon-prone areas. Materials and Methods: In this study, we randomly investigated eight plots of 30 m × 30 m in pure and mixed-Eucalyptus (Eucalyptus urophylla S. T. Blake × E. grandis W. Hill) plantations of different tree species (Neolamarckia cadamba (Roxb.) Bosser, Acacia mangium Willd., and Pinus elliottii var. Elliottii Engelm. × P. caribaea Morelet) on growth status, characterized and compared the distribution of nonspatial structure of the monoculture and mixtures, and evaluated the stand quality and stability from eight indexes of the nonspatial structure, including preservation rate, stand density, height, diameter, stem form, degree of stem inclination, tree-species composition, and age structure. Results: Eucalyptus surviving in the mixed plantation of Eucalyptus and A. mangium (EA) and in the mixed plantation of Eucalyptus and P. elliottii × P. caribaea (EP) were 5.0% and 7.6% greater than those in pure Eucalyptus plantation (EE), respectively, while only the stand preservation rate of EA was greater (+2.9%) than that of the pure Eucalyptus plantation. The proportions of all mixtures in the height class greater than 7 m were fewer than that of EE. The proportions of EA and mixed plantation of Eucalyptus and N. cadamba (EN) in the diameter class greater than 7 m were 10.6% and 7.8%, respectively, more than that of EE. EN had the highest ratio of branching visibly (41.0%), EA had the highest ratio of inclined stems (8.1%), and EP had the most straight and complete stem form (68.7%). The stand stability of the mixed plantation of Eucalyptus and A. mangium presented to be optimal, as its subordinate function value (0.76) and state value (ω = 0.61) of real stand were the largest. Conclusions: A. mangium is a superior tree species to mix with Eucalyptus for a more stable stand structure in the early growth stage to approach an evident and immense stability and resistance, which is of great significance for the forest restoration of Eucalyptus in response to extreme climate and forest management.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Purhonen Jenna ◽  
Abrego Nerea ◽  
Komonen Atte ◽  
Huhtinen Seppo ◽  
Kotiranta Heikki ◽  
...  

AbstractThe general negative impact of forestry on wood-inhabiting fungal diversity is well recognized, yet the effect of forest naturalness is poorly disentangled among different fungal groups inhabiting dead wood of different tree species. We studied the relationship between forest naturalness, log characteristics and diversity of different fungal morpho-groups inhabiting large decaying logs of similar quality in spruce dominated boreal forests. We sampled all non-lichenized fruitbodies from birch, spruce, pine and aspen in 12 semi-natural forest sites of varying level of naturalness. The overall fungal community composition was mostly determined by host tree species. However, when assessing the relevance of the environmental variables separately for each tree species, the most important variable varied, naturalness being the most important explanatory variable for fungi inhabiting pine and aspen. More strikingly, the overall species richness increased as the forest naturalness increased, both at the site and log levels. At the site scale, the pattern was mostly driven by the discoid and pyrenoid morpho-groups inhabiting pine, whereas at the log scale, it was driven by pileate and resupinate morpho-groups inhabiting spruce. Although our study demonstrates that formerly managed protected forests serve as effective conservation areas for most wood-inhabiting fungal groups, it also shows that conservation planning and management should account for group- or host tree -specific responses.


2020 ◽  
Vol 48 ◽  
pp. 11-25
Author(s):  
Paloma de las Heras ◽  
Silvia Medina-Villar ◽  
M.Esther Pérez-Corona ◽  
Beatriz R. Vázquez-de-Aldana

2020 ◽  
pp. 12-19
Author(s):  
Yu. V. Chesnokov

Modern crop cultivation technologies have reached the limits of “saturation” both in the ecological (environmental pollution, suppression of the mechanisms of its self-regulation), energy (exponential growth of irreplaceable energy costs for each additional unit of production), and in production. In this regard, environmental factors (air drought, frosts, active temperatures, etc.), which cannot be optimized, are becoming increasingly important in ensuring a steady increase in the yield of cultivated plant forms. In recent decades, more and more attention has been paid to technogenic and biological systems of agriculture, based on the ecologization and biologization of the intensification processes of adaptive crop production. Such approaches are the precision agriculture system (PA) and QTL analysis. Using these approaches allows not only to ensure a steady increase in productivity due to the combined use of the advantages of precision farming and molecular genetic assessment, including the creation of new forms and varieties that are responsive to РА agricultural practices, but also to level the negative impact of abiotic and biotic environmental factors that limit the size and quality of the crop as well as plant productivity. It is shown that the strategy of adaptive intensification of crop production through the use of the TK system and QTL analysis approaches is not alternative to existing farming systems, however, it focuses modern agriculture on the growth of knowledge-intensive agricultural production as a whole. An analysis of the causes under consideration, the current unfavorable trends in modern crop production and agriculture, clearly shows their scale and long-term nature, and therefore the inevitability of the search for new priorities for intensification of crop production and agriculture, providing a qualitatively new stage of their development in the interests of man.


Author(s):  
P. C. Nnadi ◽  
B. B. Otene ◽  
Nwiisator David-Sarogoro

This study was carried out to examine the distribution of plant species in Rivers State University campus at different locations at the Rivers State University Nkpolu-Oroworukwo Port Harcourt Nigeria. The general objective of this study was to examine the Ecological distribution of plant species in Rivers State University campus at different locations. The specific objective was to determine the species abundance of various plants in the study area and also to examine the ecological diversity of tree species in the various groups. The study area was divided into three groups (stations) with the various plants species identified and recorded. Data gotten from the field was analyzed using descriptive statistic and some ecological indices such as Margalef, Mehinick, Shannon diversity, Shannon Wiener, Evenness/Equitability and Simpson dominance.  A total of one thousand Sixty-nine (1069) individual plant were identified with 16, 17 and 12 species in stations 1-3 respectively. The highest individual plants (561) were observed in station 1 while the least (87) were observed in station 3. The mean values of stations 1 and 2 were significantly and statistically different from site 3 at p<0.05. The results obtained showed some dominant species to include Elaeis guincensis, Polyaithia longifolia, Pinus spp, Gmelina arborea, Wodyetia bifareata, Citrus sinensis, Cocos nuciferia while others were the least dominant species found in the study area. The Margalef, Mehinicks and Shannon Wiener values were consistently highest in station 2 but lowest in station 3.  Human disturbances had negative impact on tree species abundance especially in site 3. It is therefore recommended that management interventions are necessary in other to stop indiscriminate felling of the various trees species that made up the different groups.


1989 ◽  
Vol 12 (2) ◽  
pp. 55
Author(s):  
R.W. Braithwaite

The location of shelter used by nine species of small mammals released after capture during a mark-recapture study in tropical woodland and open forest was recorded whenever possible. A quantitative profile of such post-release behaviour by different species permits its incorporation into analyses of habitat selection. Characteristics of post-release behaviour also provide clues about the nature of predation pressure on various species. Arboreal species tended to select tree species with boles having camouflage potential. Small species used small holes. Scansorial species used the greatest range of sheltering sites. Average distance moved to shelter was inversely related to the mean density of a species.


2021 ◽  
Vol 14 (2) ◽  
pp. 16-23
Author(s):  
Kinjouo Ghislain Kenguem ◽  
Victor François Nguetsop ◽  
Solefack Marie Caroline Momo

Les forêts d’Afrique centrale contiennent plusieurs produits d’origine animale et végétale. Les produits d’origine végétale peuvent se distinguer en produits forestiers ligneux et non ligneux. Le présent travail de recherche porte sur l’importance et la gestion durable de quelques Produits Forestiers Non Ligneux (PFNL), notamment l’écorce de trois arbres (Garcinia lucida, Scorodophloeus zenkeri, Alstonia boonei) dans la localité de Ngovayang I. À l’aide d’un questionnaire semi-structuré, les caractéristiques du secteur des PFNL, les stratégies de gestion, ainsi que l’impact de la valorisation des PFNL ont été déterminés. Il ressort des enquêtes que les écorces de ces trois espèces sont connues et utilisées à des fins diverses telles que la consommation, l’automédication et la vente. L’initiation à l’utilisation de l’écorce de ces espèces est liée au sexe et est également fonction de l’âge des enquêtés. Leurs écorces sont approvisionnées sur le marché et vendues en majorité par les hommes. G. lucida et S. zenkeri sont utilisées à des fins nutritionnelles, médicinales et lucratives, tandis qu’Alstonia boonei est utilisée exclusivement à des fins médicinales. Pour des personnes plus jeunes, d’une tranche d’âge comprise entre 15 et 35 ans, l’exploitation de l’écorce de ces trois espèces n’a aucun impact néfaste sur la disponibilité des ressources forestières. S’agissant des personnes âgées de 35 à 65 ans, l’exploitation non contrôlée et l’écorçage anarchique de G. lucida et de S. zenkeri peuvent entrainer leur pénurie et même leur disparition dans cette région. Toutefois, la récolte échelonnée de l’écorce de G. lucida, S. zenkeri et A. boonei est utilisée comme stratégie de gestion de l’écorce de ces arbres dans cette localité.   Central African forests are teemed with several goods of animal and plant origin. Goods of plant origin are forest products and non-timber forest products. This research work focused on the identification and importance of some non-timber forest products (NTFPs), especially the bark of tree species (Garcinia lucida, Scorodophloeus zenkeri and Alstonia boonei) in the locality of Ngovayang I. Using a semi-structured questionnaire, the characteristics of the NTFP sector, management strategies, and the impact of NTFP exploitation were determined in Ngovayang I. Surveys show that the bark of these three species is well known and used for various purposes such as consumption, self-medication and sale. The initiation of the use of the bark of these species is linked to sex and also depends on the age of the respondents. Their bark is supplied on the market and sold mostly by men. G. lucida and S. zenkeri are used for food, medicinal and profit-making purposes, while A. boonei is used exclusively for medicinal purposes. For younger people, aged between 15 and 35 years old, the exploitation of the bark of these three species has no negative impact on forest resources. For old people (35 to 65 years), the uncontrolled exploitation and uncontrolled debarking of G. lucida and S. zenkeri can lead to the shortage and even extinction of these two tree species in the region. However, the planned harvest of the bark of Garcinia lucida, Scorodophloeus zenkeri and Alstonia boonei is used as strategy of management of the bark of these trees in this locality.


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