The relationship between species richness and biomass changes from boreal to subtropical forests in China. Xian Wu, Xiangping Wang, Zhiyao Tang, Zehao. The relationship between biodiversity and biomass is an essential element of the natural ecosystem functioning. Our research aims at. Both biodiversity and biomass are important variables in forest ecosystems, and the relationship between them is critical for ecosystem.
Meanwhile, climate moisture index not only affected positively on aboveground biomass, but also indirectly through species richness.
The information would be helpful in understanding the biodiversity-aboveground biomass relationship of a primary P. Introduction Biodiversity and biomass are two critical variables in the plant community ecosystem [ 1 ]. Biodiversity declines have led to widespread concern about the loss of ecosystem function resulting from human disturbance including deforestation and afforestation under the background of global climate change [ 2 ].
The biodiversity-biomass relationship has become a major ecological focus worldwide over recent decades [ 34 ]. However, the relationship between species diversity and biomass sometimes instead of productivity has led to more controversial conclusions: The original studies discussed relationships in experimental communities, especially in fast-growing ecosystems with simple community structure, such as grasslands, meadows, and wetlands [ 7 ].
The ecologists have discovered that increasing plant diversity tends to be correlated with higher community productivity since the s [ 89 ].
Recently, equivocal findings have been obtained from existing studies with respect to the fundamental relationship between plant species diversity and biomass or productivity.
Most studies have found that biodiversity could increase community biomass or productivity, whether in simple grassland ecosystems or in complex natural forest ecosystems [ 41011 ]. A few studies found that lower biodiversity levels are associated with higher biomass production [ 1213 ]. Others have found few consistent relationships in natural ecosystems [ 91415 ].Biology Biodiversity & Conservation part 6 (Species - Area , Relationship) class 12 XII
The unimodal curve was the common variation tendency found between biodiversity and biomass in the different natural ecosystems using observation methods [ 16 ], but no findings depicted consistent causal mechanisms. The driving mechanisms of the biodiversity-biomass variations may be explained by the sampling effect and the complementary effect, both highly contingent on our understanding of complex natural communities and spatial variation scales [ 2 ].
Generally speaking, the sampling effect could illustrate that the most productive species will ultimately dominate the proportion of community biomass, while the complementary effect could enhance a functioning process such as productivity through niche partitioning and interspecific facilitation, leading to more utilization of resources [ 1017 ].
Species richness and biomass-how are they related?
The sampling effect and the complementary effect are not mutually exclusive, and both mechanisms will likely affect biomass and productivity. The intensity of responses had larger variation in differing environments and the complementary effect accounted for a large proportion of explanatory ability in large-scale patterns [ 1518 ].
In the case of forest ecosystems, the hypothesis that increasing tree species diversity translates into elevated biomass accumulation is difficult to evaluate through experimental manipulations such as those conducted in grassland ecosystems. Because of the much slower growth of trees, it is difficult to explore the ecological impact on the biodiversity-biomass relationship.
Species richness and biomass-how are they related? | Oikos Journal
Rather, it is more feasible to explore relationships through meta-analysis of existing datasets. Multivariate analysis techniques have been used to develop understanding of biodiversity-biomass relationships [ 1719 ].
The relationship between plant species diversity and biomass accumulation has been examined in different types of forests using a range of statistical methods. For example, Zhang and Chen found a positive correlation between diversity and aboveground biomass in a natural temperate spruce and pine forest [ 17 ]. In contrast, Jerzy and Anna found a weak negative relationship between species diversity and biomass accumulation in a pine forest of Europe [ 13 ].
One possible explanation for these differences among existing studies is that the most competitive tree species may not always be the most productive and complementary effect on both environmental conditions and species functional characteristics [ 20 ]. Interactions between species and the environment and between different species can shape the nature of the species diversity-biomass relationship [ 21 ].
Climate factors limited the productivity of the community in a larger scale, while hygrothermal index could explain a larger proportion of pine forest productivity [ 22 ].
Positive species diversity and biomass relationships are ubiquitous in most forest ecosystems around the world, and species loss in these ecosystems negatively impacts ecosystem functioning 34. Most previous research has focused on the relationship between species diversity and productivity, not biomass, in forest ecosystems 56. However, biomass is strongly correlated with productivity when the effects of stand age are taken into account 478. An increasing number of studies have focused on the relationship between biodiversity and aboveground biomass, as well as the mechanisms resulting in variations in both species functional traits and environmental conditions in tropical, temperate and boreal forest ecosystems 49.
Previous studies have shown that tree species in the overstory play important roles in mediating the effects of environmental conditions and disturbance on understory species richness 10 Accordingly, studies on the relationships between species richness and biomass across forest strata have been carried out in boreal and subtropical forests 911 — Simultaneously, similar findings have also indicated that diversity-productivity relationships in the forest understory were not associated or were negatively associated with the aboveground biomass of the overstory layer 7.
In contrast, the species diversity of the overstory layer significantly increased the species diversity of the understory layer in a subtropical forest, while the effect of the aboveground biomass of the overstory on the diversity and aboveground biomass of the understory was negligible The occurrence of shade species from the canopy trees in the understory layer is a common phenomenon, and the overstory-understory species richness relationship suggests that different functional groups have specific growth strategies There is no doubt that the size of the overstory, the interaction between species richness and aboveground biomass in this layer, and its indirect effects on resource availability and heterogeneity mediate the relationship between species richness and aboveground biomass in the understory layers 712 The driving mechanisms of comprehensive causal relationships could be explained by both selection and complementarity effects A previous study demonstrated that the majority of productivity of the forest ecosystem occurred in the overstory, while understory plants have relatively low contributions to the total biomass stock The relationship between species richness and biomass is more complex in natural ecosystems because of species dominance and composition The selection effect suggests that species with the most productive traits will have greater opportunities to dominate the biomass of species-rich polycultures through interspecific competition, while the complementarity effect suggests that species can capture resources to maintain diversity as a result of niche partitioning or interspecific interactions when they occur together in plant communities 15 Although positive species diversity and aboveground biomass relationships are mostly found across forest strata that exhibit higher species richness and many trophic levels 27biotic and abiotic factors affect the magnitude and quality of such relationships, and these effects should be considered, especially by increasing the range of variables included in multivariate studies, such as competition intensity, resource heterogeneity and population dynamics Stand age is closely associated with the species richness-biomass relationship 9.
Simultaneously, the consideration of environmental conditions may be crucial for understanding the relationship between species richness and biomass along with two drivers 4: First, higher resource availability supports more biomass accumulation under more favourable climate and soil nutrient conditions Second, the diversity-productivity relationship shows a unimodal association from harsh to favourable climate and soil nutrient conditions 4.
The extents of the influences of climate and local site conditions on plant species diversity differ significantly among vegetation strata Climate, soil nutrient conditions and stand age are recognized as directly or indirectly affecting the species richness-aboveground biomass relationship, but were rarely explicitly considered because of the instability in environmental conditions 9 In Yunnan Province, China, primary Pinus kesiya forests play an important role in local forest ecosystem functioning, including carbon sequestration and biological conservation, in addition to timber production and resin tapping.