scholarly journals Changes in taxonomic and functional diversity of plants in a chronosequence of Eucalyptus grandis plantations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pamela E. Pairo ◽  
Estela E. Rodriguez ◽  
M. Isabel Bellocq ◽  
Pablo G. Aceñolaza

AbstractTree plantations have become one of the fastest-growing land uses and their impact on biodiversity was evaluated mainly at the taxonomic level. The aim of this study was to analyze environmental changes after the Eucalyptus plantation in an area originally covered by natural grasslands, taking into account the alpha and beta (taxonomic and functional) diversity of plant communities. We selected nine plantation ages, along a 12 years chronosequence, with three replicates per age and three protected grasslands as the original situation. At each replicate, we established three plots to measure plant species cover, diversity and environmental variables. Results showed that species richness, and all diversity indices, significantly declined with increasing plantation age. Canopy cover, soil pH, and leaf litter were the environmental drivers that drove the decrease in taxonomic and functional diversity of plants through the forest chronosequence. Based on the path analyses results, canopy cover had an indirect effect on plant functional diversity, mediated by leaf litter depth, soil pH, and plant species richness. The high dispersal potential, annual, barochorous, and zoochorous plant species were the functional traits more affected by the eucalypt plantations. We recommend two management practices: reducing forest densities to allow higher light input to the understory and, due to the fact that leaf litter was negatively associated with all diversity facets, we recommend reducing their accumulation or generate heterogeneity in its distribution to enhance biodiversity.

2020 ◽  
Author(s):  
Pamela E. Pairo ◽  
Estela E. Rodriguez ◽  
M. Isabel Bellocq ◽  
Pablo G. Aceñolaza

ABSTRACTUnderstanding how human land-uses impact on local communities is required to implement management and conservational policies and practices. Tree plantations have become one of the fastest-growing land uses in recent decades and their impact on biodiversity was evaluated mainly at the taxonomic level. Our aim was to analyze the effects of changes in environmental drivers along the 12 years eucalypt plantations chronosequence on alfa, beta, taxonomic and functional diversity of understory plant communities. We selected nine plantation ages with three replicates per age and three protected grasslands as reference habitat. At each replicate, we established three plots to measure plant species cover and environmental variables, which are expected to change with plantation age. Results showed that species richness and all diversity indices significantly declined with increasing plantation age. Canopy cover, soil pH, and leaf litter were the most important drivers that explained the decline in taxonomic and functional diversity of plants through the forest plantation. Based on the Path analyses results, canopy cover had an indirect relationship with plant functional diversity mediated by leaf litter, soil pH and plant species richness. The results of the association between functional traits and environmental variables have revealed that high dispersal potential, annual, barochorous, and zoochorous plant species were the functional traits more affected by the eucalypt plantations. Given that leaf litter was negatively associated with all diversity facets, we recommend reducing their accumulation within eucalypt plantation to enhance biodiversity conservation and the provision of pampean grassland ecosystem functions.


2020 ◽  
Author(s):  
Noémie A. Pichon ◽  
Seraina L. Cappelli ◽  
Santiago Soliveres ◽  
Tosca Mannall ◽  
Thu Zar Nwe ◽  
...  

SummaryThe ability of an ecosystem to deliver multiple functions at high levels (multifunctionality) typically increases with biodiversity but there is substantial variation in the strength and direction of biodiversity effects, suggesting context-dependency. However, the drivers of this context dependency have not been identified and understood in comparative meta-analyses or experimental studies. To determine how different factors modulate the effect of diversity on multifunctionality, we conducted a large grassland experiment with 216 communities, crossing a manipulation of plant species richness (1-20 species) with manipulations of resource availability (nitrogen enrichment), plant functional composition (gradient in mean specific leaf area [SLA] to manipulate abundances of fast vs. slow species), plant functional diversity (variance in SLA) and enemy abundance (fungal pathogen removal). We measured ten functions, above and belowground, related to productivity, nutrient cycling and energy transfer between trophic levels, and calculated multifunctionality. Plant species richness and functional diversity both increased multifunctionality, but their effects were context dependent. Species richness increased multifunctionality, but only when communities were assembled with fast growing (high SLA) species. This was because slow species were more redundant in their functional effects, whereas fast species tended to promote different functions. Functional diversity also increased multifunctionality but this effect was dampened by nitrogen enrichment, however, unfertilised, functionally diverse communities still delivered more functions than low diversity, fertilised communities. Our study suggests that a shift towards exploitative communities will not only alter ecosystem functioning but also the strength of biodiversity-functioning relationships, which highlights the potentially complex effects of global change on multifunctionality.


Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 300 ◽  
Author(s):  
Pradeep Wagle ◽  
Prasanna Gowda

Adoption of better management practices is crucial to lessen the impact of anthropogenic disturbances on tallgrass prairie systems that contribute heavily for livestock production in several states of the United States. This article reviews the impacts of different common management practices and disturbances (e.g., fertilization, grazing, burning) and tallgrass prairie restoration on plant growth and development, plant species composition, water and nutrient cycles, and microbial activities in tallgrass prairie. Although nitrogen (N) fertilization increases aboveground productivity of prairie systems, several factors greatly influence the range of stimulation across sites. For example, response to N fertilization was more evident on frequently or annually burnt sites (N limiting) than infrequently burnt and unburnt sites (light limiting). Frequent burning increased density of C4 grasses and decreased plant species richness and diversity, while plant diversity was maximized under infrequent burning and grazing. Grazing increased diversity and richness of native plant species by reducing aboveground biomass of dominant grasses and increasing light availability for other species. Restored prairies showed lower levels of species richness and soil quality compared to native remnants. Infrequent burning, regular grazing, and additional inputs can promote species richness and soil quality in restored prairies. However, this literature review indicated that all prairie systems might not show similar responses to treatments as the response might be influenced by another treatment, timing of treatments, and duration of treatments (i.e., short-term vs. long-term). Thus, it is necessary to examine the long-term responses of tallgrass prairie systems to main and interacting effects of combination of management practices under diverse plant community and climatic conditions for a holistic assessment.


2019 ◽  
pp. 1-12 ◽  
Author(s):  
Erica Juel Ahrenfeldt ◽  
Johannes Kollmann ◽  
Henning Bang Madsen ◽  
Hans Skov-Petersen ◽  
Lene Sigsgaard

In Western Europe agricultural management was intensified in the period 1950–2010 with negative consequences for ecosystem services, such as pollination, especially in countries with a large proportion of agriculture. Farmland represents 66% of the Danish landscape, but little is known about wild bees despite that 75% of the country’s wild and cultivated plant species depend on insect pollination. Strawberry (Fragaria × ananassa) gains considerable benefits from insect pollination and abundance, species richness and functional diversity, are all important elements. We surveyed the diversity of wild bees during strawberry flowering by sampling bees with pan-traps along permanent margins bordering strawberry fields on six organic and six conventional farms in eastern Denmark and compared the results of the survey with that of sampling site farming practice and field margin forage availability. The majority of bees sampled were polylectic solitary ground-nesting bees known to forage on species of the rose family. This indicates that these bee species are potential pollinators of strawberries, and the low number of specialized bees suggests that the bee community was affected by the simplified landscapes. Temporal trends in abundance, species richness, and body size of the bees, suggest that the functional diversity of pollinator assemblages available differed for early- and late-flowering strawberries. Fewer plants species and a lower plant cover were found in the margins of sprayed fields. Abundance and diversity of the wild bees were neither correlated with the use of herbicides and insecticides, nor with plant species richness or flowering plant cover.


2019 ◽  
Vol 98 ◽  
pp. 266-275 ◽  
Author(s):  
Natalia Crespo-Mendes ◽  
Alexis Laurent ◽  
Hans Henrik Bruun ◽  
Michael Zwicky Hauschild

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