Forest recovery in the humid tropics: changes in vegetation structure, nutrient pools and the hydrological cycle

Author(s):  
D. Hölscher ◽  
J. Mackensen ◽  
J. -M. Roberts
2021 ◽  
Author(s):  
Monica Kaushik ◽  
Sutirtha Dutta ◽  
Gopal S. Rawat ◽  
Pratap Singh ◽  
Dhananjai Mohan

AbstractMost tropical forests have undergone commercial logging. Even where logging has ceased, subsistence harvest of forest resources often persists especially in South-East Asia. Understanding of impacts of frequent forest resources extraction in areas recovering from past selective logging would be essential for designing the appropriate management interventions.We studied the impacts of current chronic anthropogenic disturbances (hereafter CAD) and past selective logging on vegetation structure, diversity, and regeneration, and the invasion of a non-native shrub, Lantana camara, in three major forest types in the Himalayan foothills, India. We analyzed field data on intensity of CAD and vegetation variables, collected from 269 stratified random plots, using ordination and generalized linear (mixed) modeling approaches.Our results, based on 2758 adult trees of 54 species, showed that forest types differed in disturbance regimes depending on protection level and availability of fodder tree species. Intensity of CAD depended on proximity to settlements (for livestock related disturbances). Whereas selective logging, including firewood collection, was associated with land protection status. Selective logging reduced the extent of mature forest but facilitated regeneration, thereby promoting secondary forest features such as tree density and canopy cover. In contrast, the interaction between lopping and selective logging was negatively associated with regeneration. Past logging facilitated L. camara invasion in Dry and Hill forests but not in Moist forest. Finally, while selective logging marginally enhanced tree diversity, CAD reduced native shrub diversity.Our study demonstrates that selective logging followed by CAD arrest forest recovery, as evident from the suppression of mature forest elements, loss of shrub biomass, reduced regeneration rate, and facilitation of invasive species. To abate these impacts, alternative livelihood/subsistence options that sustain forests and local communities should be explored. Additionally, CAD management should be site-specific as local ecological contexts modify their impacts on forests.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3917 ◽  
Author(s):  
Anicet Gbéblonoudo Dassou ◽  
Philippe Tixier ◽  
Sylvain Dépigny ◽  
Dominique Carval

In tropics, ants can represent an important part of animal biomass and are known to be involved in ecosystem services, such as pest regulation. Understanding the mechanisms underlying the structuring of local ant communities is therefore important in agroecology. In the humid tropics of Africa, plantains are cropped in association with many other annual and perennial crops. Such agrosystems differ greatly in vegetation diversity and structure and are well-suited for studying how habitat-related factors affect the ant community. We analysed abundance data for the six numerically dominant ant taxa in 500 subplots located in 20 diversified, plantain-based fields. We found that the density of crops with foliage at intermediate and high canopy strata determined the numerical dominance of species. We found no relationship between the numerical dominance of each ant taxon with the crop diversity. Our results indicate that the manipulation of the densities of crops with leaves in the intermediate and high strata may help maintain the coexistence of ant species by providing different habitat patches. Further research in such agrosystems should be performed to assess if the effect of vegetation structure on ant abundance could result in efficient pest regulation.


2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Zulkifli Aiyub Kadir ◽  
Bahagia Bahagia

<p>Humans have utilized landscape for  produces a diverse character of the wider area of the watershed. Agroforestry is a land management system in addressing the problems that arise due to changes in land use of soil and water conservation. The aim of the study was to analyze plant diversity in agroforestry practices that have services in the Krueng watershed landscape in Aceh watershed. Develop strategies in the Krueng Aceh DAS agroforestry service. This research was conducted in the upper, middle and downstream of the Krueng Aceh watershed, with a rapid method of Agro-Biodiversity Appraisal and SWOT. The results showed that the composition of the vegetation structure found in the study sites tended to vary with the diversity index of agroforestry that was currently in the upstream and middle of the Krueng Aceh watershed. Based on SWOT analysis, internal scores are 2.45 and external scores are 3.21. Agroforestry practices in the upper stream of Krueng Aceh watershed were dominated by <em>Aleurites moluccana</em>, <em>Areca cathecu</em>, and  <em>Averrhoa bilimbi</em> L  species with the highest INP in the upper stream of Krueng Aceh watershed. Vegetation at the middle stream of Krueng Aceh watershed dominated by <em>Areca cathecu,</em> <em>Lansium domesticum</em> and Musa<em> paradisiaca</em>.  </p>


2017 ◽  
Vol 23 (1) ◽  
Author(s):  
V.K. YADAV ◽  
SONAM SHARMA ◽  
A.K. SRIVASTAVA ◽  
P.K. KHARE

Ponds are an important fresh water critical ecosystem for plants and animals providing goods and services including food, fodder, fish, irrigation, hydrological cycle, shelter, medicine, culture, aesthetic and recreation. Ponds cover less than 2 percent of worlds land surface. Ponds are important source of fresh water for human use. These are threatened by urbanization, industrialization, over exploitation, fragmentation, habitat destruction, pollution, illegal capturing of land and climate changes. These above factors have been destroying ponds very rapidly putting them in danger of extinction of a great number of local biodiversity. It is necessary to formulate a correct conservation strategy for pond restoration in order to meet the growing needs of fresh water by increasing the human population. Some measures have been compiled and proposed in the present review.


2021 ◽  
Vol 657 ◽  
pp. 59-71
Author(s):  
BA Beckley ◽  
MS Edwards

The forest-forming giant kelp Macrocystis pyrifera and the communities it supports have been decreasing across their native ranges in many parts of the world. The sudden removal of giant kelp canopies by storms increases space and light for the colonization by understory macroalgae, such as Desmarestia herbacea, which can inhibit M. pyrifera recovery and alter local community composition. Understanding the mechanisms by which algae such as D. herbacea interact with M. pyrifera can provide insight into patterns of kelp forest recovery following these disturbances and can aid in predicting future community structure. This study experimentally tested the independent and combined effects of two likely competitive mechanisms by which D. herbacea might inhibit recovery of M. pyrifera in the Point Loma kelp forest in San Diego, California (USA). Specifically, we conducted field experiments to study the individual and combined effects of shade and scour by D. herbacea on the survival of M. pyrifera microscopic life stages, and the recruitment, survival, and growth of its young sporophytes. Our results show that scour had the strongest negative effect on the survival of M. pyrifera microscopic life stages and recruitment, but shade and scour both adversely affected survival and growth of these sporophytes as they grew larger. Canopy-removing storms are increasing in frequency and intensity, and this change could facilitate the rise of understory species, like D. herbacea, which might alter community succession and recovery of kelp forests.


2018 ◽  
Vol 30 (1) ◽  
pp. 173-193 ◽  
Author(s):  
Yeongjun Cho ◽  
Hasong Kim ◽  
Hyeonho Myeong ◽  
Jungwon Park ◽  
Janggeun Oh

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