scholarly journals Disentangling the effects of past logging and ongoing cryptic anthropogenic disturbance on vegetation structure and composition in Himalayan Foothills, India

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.

2012 ◽  
Vol 84 (3) ◽  
pp. 721-726
Author(s):  
Cássius R. Santana ◽  
Gabriela M. Bochio ◽  
Luiz dos Anjos

We evaluated the distribution of abundance of three species of warblers in the southern portion of the Brazilian Atlantic Forest (BAF): Tropical Parula (Parula pitiayumi), the Golden-Crowned Warbler (Basileuterus culicivorus) and the White-Rimmed Warbler (Basileuterus leucoblepharus). Three types of forests comprise this region of the Atlantic Forest: seasonal semi-deciduous forest (SF), mixed rain forest (MF) and dense rain forest (DF). These forest types occur at different elevations: SF ranging from 200 to 800 m, MF ranging from 800 to 1,200 m and DF ranging from sea level up to 2,000 m. We used point counts in fifteen study areas distributed in the three forest types. The White-Rimmed Warbler and the Tropical Parula had higher abundances in MF, and their abundance was positively correlated with the elevation. The Golden-Crowned Warbler did not present a significant difference in abundance among the forest types, and no correlation between abundance and elevation was found. We suggest that the difference in the occupancy of the forest strata by the Golden-Crowned Warbler is because this species is more generalist and thus less sensitive to variations in the vegetation structure among the forests types when compared to the other two warbler species.


The Auk ◽  
2007 ◽  
Vol 124 (2) ◽  
pp. 494-507 ◽  
Author(s):  
Andrew C. Vitz ◽  
Amanda D. Rodewald

AbstractRecent studies have demonstrated that many birds of mature forests heavily use early-successional habitat during the postbreeding period. Two frequently invoked hypotheses to explain these shifts are that postbreeding birds select (1) dense cover to reduce risk of predation and (2) abundant fruit resources to facilitate foraging. Using mist nets between 15 June and 16 August in 2002 and 2003, we captured mature-forest birds during the postbreeding period in 12 regenerating hardwood clearcuts (three to seven years old) in southeast Ohio. Vegetation structure and fruit resources were measured at nine net locations within each clearcut. We applied an information-theoretic approach, where we used vegetative and fruit variables as predictors in seven a priori models to evaluate how habitat factors might explain capture rates. In two seasons, we captured 1,089 hatch-year (HY) and 445 after-hatch-year (AHY) postbreeding birds of 32 mature-forest species. In general, models reflecting habitat structure (density of low vegetation, canopy height) best explained variation in capture rates, which were negatively related to the density of low vegetation (<1.5 m) and positively related to canopy height. Extremely dense low vegetation may be disadvantageous if it inhibits movements and provides cryptic locations for ground predators. Instead, habitats with greater vertical structure (e.g., taller vegetation) and relatively less dense low vegetation below may provide better protection from aerial and ground predators. Overall, results suggest that vegetation structure may explain high use of early-successional forests by many birds during the postbreeding period, though fruit may be the most important factor for seasonal frugivores.Recursos Vegetativos y de Frutos como Determinantes del Uso de Hábitat por Aves de Bosque Maduro Durante el Período Posterior a la Reproducción


Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1027
Author(s):  
Dandan Qi ◽  
Fujuan Feng ◽  
Yanmei Fu ◽  
Ximei Ji ◽  
Xianfa Liu

Microbes, as important regulators of ecosystem processes, play essential roles in ecosystem recovery after disturbances. However, it is not clear how soil microbial communities and functions change and affect forest recovery after clear-cutting. Here, we used metagenome sequencing to systematically analyse the differences in soil microbial community composition, functions, and nitrogen (N) cycling pathways between primary Korean pine forests (PF) and secondary broad-leaved forests (SF) formed after clear-cutting. Our results showed that the dominant phyla of the two forest types were consistent, but the relative abundance of some phyla was significantly different. Meanwhile, at the genus level, the fold-changes of rare genera were larger than the dominant and common genera. The genes related to microbial core metabolic functions, virulence factors, stress response, and defence were significantly enriched in SF. Additionally, based on the relative abundance of functional genes, a schema was proposed to analyse the differences in the whole N cycling processes between the two forest types. In PF, the stronger ammoniation and dissimilatory nitrate reduction (DNRA) and the weaker nitrification provided a genetic explanation for PF dominated by ammonium (NH4+) rather than nitrate (NO3−). In SF, the weaker DNRA, the stronger nitrification and denitrification, the higher soil available phosphorus (AP), and the lower nitrogen to phosphorus ratio (N/P) comprehensively suggested that SF was faced with a greater degree of N limitation. These results offer insights into the potential relationship between soil microbes and forest recovery, and aid in implementing proper forestry management.


2010 ◽  
Vol 113-116 ◽  
pp. 1250-1255
Author(s):  
Tie Dong Liu ◽  
Wen Feng Gong ◽  
Wei Hong Wang

This paper, based on the forest map of Mao’er Mountain in 1983 and forest inventory sub-compartment database of Mao’er Mountain in 2004, and with the support of geographical information system (GIS), presents the results of study of forest resource change in the periods, which reflected the change of forest type spatial distribution. Furthermore, this study focuses on the construction and present situation of dynamic forest resource by overlaying the forest resource distribution with DEM in which the vectorization of topographical maps was made by using the vector data for creating the digital elevation model (DEM). The results demonstrate that the area of study region decreased to 216 hm2; and the area of open forest land, new afforestation, non-standing forest, farmland and wetland were decreased; the area of forest land, rivers and lakes, agricultural land and the road land are increasing. Meanwhile, it also indicts that the construction of forest resources was not reasonable, in which the proportions of midlife and near-mature forest are larger, the stocks of midlife and near-mature forest increases, and the stock of mature forest decreased greatly. Finally, the study focuses on the forest resource spatial distribution by overlay analysis combined DEM with forest resources construction, which aimed to adjust the current unreasonable situation for the sustainable management of forest resources in the future.


Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 650 ◽  
Author(s):  
Lu ◽  
Feng ◽  
Zhu

Forests are important in the global carbon cycle and it is necessary to quickly and accurately measure forest volume to estimate forest aboveground biomass (AGB) and aboveground carbon storage (AGC). In this paper, we used data from the eighth forest resources inventory of China to establish two stand volume models based on stand density and forest basal area for 37 arbor forest types (dominant species); and performed a comparative analysis to obtain the best model. Then the AGB, AGB density, AGC, and AGC density of the different forest types and regions were estimated by conversion function methods. The results showed that: (1) The volume model of tree height and forest basal area could better fit the natural growth process of forests, and 36 of the 37 forest types had R2 greater than 0.8; (2) The average AGB density of arbor forest in China was 95.03 Mg ha−1 and the average AGC density was 48.15 Mg ha−1 (3) Among forest types, Picea asperata Mast., Quercus spp., and Populus spp. had the highest AGB and AGC, while Cinnamomum camphora (L.) Presl, Pinus taiwanensis Hayata, and Pinus densiflora Sieb. et Zucc. had the lowest. The AGB density and AGC density of Phoebe zhennan S. Lee et F. N. Wei and Pinus densata Mast. were the highest, while those of Pinus densiflora Sieb. et Zucc., Pinus elliottii Engelmann, and Eucalyptus robusta Smith were the lowest. (4) Among regions, AGB and AGC ranging from high to low, were as follows: northwest, southwest, northeast, central south, east, and north. The northwest and southwest regions accounted for more than 70% of the country’s AGB and AGC. The average AGB density and AGC density among the regions were 91.34 Mg ha−1 and 46.4 Mg ha−1, respectively. Ranging from high to low as follows: southwest, northwest, northeast, east, central south, and north. The methods used in this paper provide a basis for fast and accurate estimation of stand volume, and the estimates of AGB and AGC have important reference value for explaining the role of ecosystems in coping with global climate change in China.


2019 ◽  
Vol 88 (2) ◽  
Author(s):  
Wiktoria Hryń ◽  
Joanna Czarnecka ◽  
Ignacy Kitowski ◽  
Piotr Bartmiński ◽  
Robert Zubel

The grey heron (<em>Ardea cinerea</em>) is a good example of an engineering species that forms nesting colonies (called heronries) composed of up to a few hundred nests during the breeding season. It exerts strong pressure on surrounding vegetation, mainly because of the heavy input of organic matter and high eutrophication. The birds also alter light conditions through direct tree damage. We aimed to examine the influence of a grey heron breeding colony on the soil properties and functional composition of the herb layer in two different forest communities: a suboceanic pine forest and a riparian mixed forest. We also wanted to establish whether these changes would make the forest ecosystem more vulnerable to colonization by nonforest species with higher light and trophic demands. Small-seeded, light demanding eutrophic species showed a tendency to be more abundant under the nests in both forest types. The calculated odds ratio (OR) showed that the probability of the presence of nonforest species under the nests was 29.5 times higher than that in the control plots (56 plants species were analyzed). Additionally, the nonforest species appeared to have high light and trophic demand (OR of 12.3 for light demand; OR of 7.0 for trophic demand), which explains the species turnover observed in the bird-affected microhabitats.


2017 ◽  
Vol 33 (4) ◽  
pp. 241-248 ◽  
Author(s):  
Sergio Javier Ceballos ◽  
Agustina Malizia

Abstract:Changes in density and basal area of lianas ≥2 cm diameter were monitored in two 1-ha permanent plots in a subtropical montane mature forest of north-western Argentina. Liana stems were identified and measured at 130 cm from the main rooting point in two censuses conducted in 2003 and 2015. Between censuses, the density of liana stems decreased 13.3%, while basal area increased 11.5%. Density and basal area decreased mainly among lianas of 2–3 cm diameter, but increased in lianas ≥4 cm diameter. Quechualia fulta (Asteraceae), Serjania meridionalis (Sapindaceae) and Chamissoa altissima (Amaranthaceae) suffered large reductions in stem density and basal area. Dissimilar responses of density and basal area of lianas might be a consequence of the suppression of anthropogenic disturbances (e.g. livestock browsing) and the decrease of treefall gap frequency in the studied forest in recent decades. Light-demanding liana species decreased and shade-tolerant species increased possibly in response to the decline in the light availability associated with forest recovery from past disturbance. Lianas increased in basal area to a lesser extent compared with reports from several tropical and subtropical forests where lianas are increasing dramatically.


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