Environmental quality and fertility: the effects of plant density, species richness, and plant diversity on fertility limitation

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).

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Biodiversity hanging by a thread: the importance of fungal litter-trapping systems in tropical rainforests

Biology Letters ◽

10.1098/rsbl.2011.1115 ◽

2011 ◽

Vol 8 (3) ◽

pp. 397-400 ◽

Cited By ~ 11

Author(s):

Jake L. Snaddon ◽

Edgar C. Turner ◽

Tom M. Fayle ◽

Chey V. Khen ◽

Paul Eggleton ◽

...

Keyword(s):

Species Richness ◽

Leaf Litter ◽

Plant Diversity ◽

Habitat Complexity ◽

Tropical Rainforests ◽

Dramatic Reduction ◽

Experimental Removal ◽

Crucial Component ◽

High Species Richness ◽

Vital Resource

The exceptionally high species richness of arthropods in tropical rainforests hinges on the complexity of the forest itself: that is, on features such as the high plant diversity, the layered nature of the canopy and the abundance and the diversity of epiphytes and litter. We here report on one important, but almost completely neglected, piece of this complex jigsaw—the intricate network of rhizomorph-forming fungi that ramify through the vegetation of the lower canopy and intercept falling leaf litter. We show that this litter-trapping network is abundant and intercepts substantial amounts of litter (257.3 kg ha −1 ): this exceeds the amount of material recorded in any other rainforest litter-trapping system. Experimental removal of this fungal network resulted in a dramatic reduction in both the abundance (decreased by 70.2 ± 4.1%) and morphospecies richness (decreased by 57.4 ± 5.1%) of arthropods. Since the lower canopy levels can contain the highest densities of arthropods, the proportion of the rainforest fauna dependent on the fungal networks is likely to be substantial. Fungal litter-trapping systems are therefore a crucial component of habitat complexity, providing a vital resource that contributes significantly to rainforest biodiversity.

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A structural gradient in cerrado vegetation of Brazil: changes in woody plant density, species richness, life history and plant composition

Journal of Tropical Ecology ◽

10.1017/s026646740200250x ◽

2002 ◽

Vol 18 (5) ◽

pp. 775-794 ◽

Cited By ~ 21

Author(s):

Luci Ferreira Ribeiro ◽

Marcelo Tabarelli

Keyword(s):

Life History ◽

Species Richness ◽

Species Composition ◽

Woody Plant ◽

Plant Density ◽

Lower Layer ◽

Sensu Stricto ◽

Life History Strategies ◽

Cerrado Vegetation ◽

Structural Types

Four structural types of cerrado vegetation were examined to test the following hypotheses: (1) there are predictable changes in woody plant density, species richness and life-history strategies from one structural type to another; and (2) plant species composition in the less-rich structural types represent particular and impoverished subsets of those found in the richer ones. The study was conducted at Fazenda Palmares (5°33′S, 42°37′W) Piauí State, Brazil. A 47% decrease in woody plant density between cerradão (forest) and the least-dense type of cerrado sensu stricto (scrub) was associated with a 40% decrease in species richness. The percentage of lower-layer species was reduced by 29% in the least dense type of cerrado sensu stricto compared to cerradão. The proportion of species that flower and fruit during the rainy season was also reduced by one third. Species were not distributed as impoverished subsets along the cerradão–cerrado sensu stricto gradient. It is argued that the reduction in woody plant density and richness is partly due to factors limiting the occurrence of species with particular life-history strategies. The species composition of structural types is affected by the ‘mass effect’ and also by surrounding biotas, which provide species that colonize particular types of cerrado vegetation. Both these processes reduce the likelihood that the species composition in the poorer structural types are simple subsets of those present in the richer types.

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Relationship between moth (night active Lepidoptera) diversity and vegetation characteristics in southern Sweden

Journal of Insect Conservation ◽

10.1007/s10841-020-00270-y ◽

2020 ◽

Vol 24 (6) ◽

pp. 1005-1015

Author(s):

Torbjörn Tyler

Keyword(s):

Species Richness ◽

Community Composition ◽

Plant Diversity ◽

Vascular Plant ◽

Habitat Characteristics ◽

Vegetation Composition ◽

Vascular Plant Diversity ◽

Site Characteristics ◽

Tree Canopy Cover ◽

Wide Range

Abstract The diversity and community composition of moths (both macro- and micromoths) at 32 sites, representing a wide range of habitat types (forests, grasslands, wetlands, agricultural and urban areas) within a restricted region in central Scania, southern-most Sweden, was investigated by use of light moth traps and compared with vascular plant species richness and habitat characteristics. The results revealed a highly significant general association between vegetation composition and the composition of the moth community and multivariate (CCA) analyses indicated light availability and soil fertility parameters (pH and macronutrients) to be the habitat characteristics that best correlated with moth community composition. Less strong, but still significant, positive relationships between moth abundance and local vascular plant diversity were also revealed. Moth species richness was positively correlated with diversity of woody plant genera in the neighborhood, but not with local vascular plant diversity in general. As for more general site characteristics, there were tendencies for higher moth richness and abundance at sites with more productive soils (well-drained, high pH, high nutrient availability), while shading/tree canopy cover, management, soil disturbance regimes and nectar production appeared unrelated to moth community parameters. It is concluded that local moth assemblages are strongly influenced by site characteristics and vegetation composition. Implications for insect conservation: The results show that obtaining moth data on a local scale is useful for conservation planning and does not need to be very cumbersome. Local moth assemblages monitored are indeed related to local site characteristics of conservation relevance.

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Superhost Plants Alter the Structure of Plant–Galling Insect Networks in Neotropical Savannas

Plants ◽

10.3390/plants8100369 ◽

2019 ◽

Vol 8 (10) ◽

pp. 369 ◽

Cited By ~ 2

Author(s):

Araújo ◽

Moreira ◽

Falcão ◽

Borges ◽

Fagundes ◽

...

Keyword(s):

Species Richness ◽

Plant Species ◽

Plant Diversity ◽

Host Plants ◽

Plant Species Richness ◽

Variable Number ◽

Insect Species ◽

Species Number ◽

Neotropical Savannas ◽

Galling Insects

Host plants may harbor a variable number of galling insect species, with some species being able to harbor a high diversity of these insects, being therefore called superhost plants. In the present study, we tested the hypothesis that the occurrence of superhost plant species of genus Qualea (Vochysiaceae) affects the structure of plant–galling insect ecological networks in Brazilian Cerrado. We sampled a total of 1882 plants grouped in 131 species and 43 families, of which 64 species and 31 families of host plants hosted 112 galling insect species. Our results showed that occurrence of superhosts of genus Qualea increased the linkage density of plant species, number of observed interactions, and the size of plant–galling insect networks and negatively affected the network connectance (but had no effect on the residual connectance). Although the occurrence of Qualea species did not affect the plant species richness, these superhosts increased the species richness and the number of interactions of galling insects. Our study represents a step forward in relation to previous studies that investigated the effects of plant diversity on the plant–insect networks, showing that few superhost plant species alter the structure of plant–herbivore networks, even without having a significant effect on plant diversity.

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Resource enrichment combined with biomass removal maintains plant diversity and community stability in a long-term grazed grassland

Journal of Plant Ecology ◽

10.1093/jpe/rtaa046 ◽

2020 ◽

Vol 13 (5) ◽

pp. 611-620

Author(s):

Feng-Wei Xu ◽

Jian-Jun Li ◽

Li-Ji Wu ◽

Xiao-Ming Lu ◽

Wen Xing ◽

...

Keyword(s):

Species Richness ◽

Species Diversity ◽

Plant Diversity ◽

Primary Productivity ◽

Management Practices ◽

Light Exposure ◽

Community Stability ◽

Water Addition ◽

Biomass Removal

Abstract Aims Long-term heavy grazing reduces plant diversity and ecosystem function by intensifying nitrogen (N) and water limitation. In contrast, the absence of biomass removal can cause species loss by elevating light competition and weakening community stability, which is exacerbated by N and water enrichment. Hence, how to maintain species diversity and community stability is still a huge challenge for sustainable management of worldwide grasslands. Methods We conducted a 4-year manipulated experiment in six long-term grazing blocks to explore combination of resource additions and biomass removal (increased water, N and light availability) on species richness and community stability in semiarid grasslands of Inner Mongolia, China. Important Findings In all blocks treated with the combination of resource additions and biomass removal, primary productivity increased and species richness and community stability were maintained over 4 years of experiment. At both species and plant functional group (PFG) levels, the aboveground biomass of treated plants remained temporally stable in treatments with the combination of N and/or water addition and biomass removal. The maintenance of species richness was primarily caused by the biomass removal, which could increase the amount of light exposure for grasses under resource enrichment. Both species asynchrony and stability of PFGs contributed to the high temporal stability observed in these communities. Our results indicate that management practices of combined resource enrichment with biomass removal, such as grazing or mowing, could not only enhance primary productivity but also maintain plant species diversity, species asynchrony and community stability. Furthermore, as overgrazing-induced degradation and resource enrichment-induced biodiversity loss continue to be major problems worldwide, our findings have important implications for adaptive management in semiarid grasslands and beyond.

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Impacts of nitrogen deposition on terrestrial plant diversity: a meta-analysis in China

Journal of Plant Ecology ◽

10.1093/jpe/rtz036 ◽

2019 ◽

Vol 12 (6) ◽

pp. 1025-1033 ◽

Cited By ~ 2

Author(s):

Wen-Juan Han ◽

Jia-Yu Cao ◽

Jin-Liang Liu ◽

Jia Jiang ◽

Jian Ni

Keyword(s):

Species Richness ◽

Plant Diversity ◽

Meta Analysis ◽

N Deposition ◽

Shannon Index ◽

N Addition ◽

Terrestrial Plant ◽

Multiple Dimensions ◽

Negative Effect ◽

Experiment Duration

AbstractAimsWith the global atmospheric nitrogen (N) deposition increasing, the effect of N deposition on terrestrial plant diversity has been widely studied. Some studies have reviewed the effects of N deposition on plant species diversity; however, all studies addressed the effects of N deposition on plant community focused on species richness in specific ecosystem. There is a need for a systematic meta-analysis covering multiple dimensions of plant diversity in multiple climate zones and ecosystems types. Our goal was to quantify changes in species richness, evenness and uncertainty in plant communities in response to N addition across different environmental and experimental contexts.MethodsWe performed a meta-analysis of 623 experimental records published in English and Chinese journals to evaluate the response of terrestrial plant diversity to the experimental N addition in China. Three metrics were used to quantify the change in plant diversity: species richness (SR), evenness (Pielou index) uncertainty (Shannon index).Important FindingsResults showed that (i) N addition negatively affected SR in temperate, Plateau zones and subtropical zone, but had no significant effect on Shannon index in subtropical zones; (ii) N addition decreased SR, Shannon index and Pielou index in grassland, and the negative effect of N addition on SR was stronger in forest than in grassland; (iii) N addition negatively affected plant diversity (SR, Shannon index and Pielou index) in the long term, whereas it did not affect plant diversity in the short term. Furthermore, the increase in N addition levels strengthened the negative effect of N deposition on plant diversity with long experiment duration; and (iv) the negative effect of ammonium nitrate (NH4NO3) addition on SR was stronger than that of urea (CO(NH2)2) addition, but the negative effect of NH4NO3 addition on Pielou index was weaker than that of CO(NH2)2 addition. Our results indicated that the effects of N addition on plant diversity varied depending on climate zones, ecosystem types, N addition levels, N type and experiment duration. This underlines the importance of integrating multiple dimensions of plant diversity and multiple factors into assessments of plant diversity to global environmental change.

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Effects of Plant Diversity and Plant Density on Ecosystem Functions in Floating Constructed Wetlands

Water Air & Soil Pollution ◽

10.1007/s11270-020-04913-3 ◽

2020 ◽

Vol 231 (11) ◽

Author(s):

Wenjuan Han ◽

Xiaoling Sheng ◽

Jiongni Shao ◽

Jia Jiang ◽

Qinru He ◽

...

Keyword(s):

Constructed Wetlands ◽

Plant Diversity ◽

Plant Density ◽

Ecosystem Functions

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Species richness alters spatial nutrient heterogeneity effects on above-ground plant biomass

Biology Letters ◽

10.1098/rsbl.2017.0510 ◽

2017 ◽

Vol 13 (12) ◽

pp. 20170510 ◽

Cited By ~ 3

Author(s):

Nianxun Xi ◽

Chunhui Zhang ◽

Juliette M. G. Bloor

Keyword(s):

Species Richness ◽

Plant Density ◽

Plant Biomass ◽

Meta Analysis ◽

Nutrient Heterogeneity ◽

Positive Effects ◽

Ground Biomass ◽

Below Ground ◽

Heterogeneity Effects ◽

Community Production

Previous studies have suggested that spatial nutrient heterogeneity promotes plant nutrient capture and growth. However, little is known about how spatial nutrient heterogeneity interacts with key community attributes to affect plant community production. We conducted a meta-analysis to investigate how nitrogen heterogeneity effects vary with species richness and plant density. Effect size was calculated using the natural log of the ratio in plant biomass between heterogeneous and homogeneous conditions. Effect sizes were significantly above zero, reflecting positive effects of spatial nutrient heterogeneity on community production. However, species richness decreased the magnitude of heterogeneity effects on above-ground biomass. The magnitude of heterogeneity effects on below-ground biomass did not vary with species richness. Moreover, we detected no modification in heterogeneity effects with plant density. Our results highlight the importance of species richness for ecosystem function. Asynchrony between above- and below-ground responses to spatial nutrient heterogeneity and species richness could have significant implications for biotic interactions and biogeochemical cycling in the long term.

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Changes in plant diversity in a water-limited and isolated high-mountain range (Sierra Nevada, Spain)

Alpine Botany ◽

10.1007/s00035-021-00246-x ◽

2021 ◽

Author(s):

Andrea Lamprecht ◽

Harald Pauli ◽

Maria Rosa Fernández Calzado ◽

Juan Lorite ◽

Joaquín Molero Mesa ◽

...

Keyword(s):

Species Richness ◽

Snow Cover ◽

Sierra Nevada ◽

Plant Diversity ◽

Endemic Species ◽

Vascular Plant ◽

Climate Change Impacts ◽

Permanent Plots ◽

High Mountain ◽

Mountain Range

AbstractClimate change impacts are of a particular concern in small mountain ranges, where cold-adapted plant species have their optimum zone in the upper bioclimatic belts. This is commonly the case in Mediterranean mountains, which often harbour high numbers of endemic species, enhancing the risk of biodiversity losses. This study deals with shifts in vascular plant diversity in the upper zones of the Sierra Nevada, Spain, in relation with climatic parameters during the past two decades. We used vegetation data from permanent plots of three surveys of two GLORIA study regions, spanning a period of 18 years (2001–2019); ERA5 temperature and precipitation data; and snow cover durations, derived from on-site soil temperature data. Relationships between diversity patterns and climate factors were analysed using GLMMs. Species richness showed a decline between 2001 and 2008, and increased thereafter. Species cover increased slightly but significantly, although not for endemic species. While endemics underwent cover losses proportional to non-endemics, more widespread shrub species increased. Precipitation tended to increase during the last decade, after a downward trend since 1960. Precipitation was positively related to species richness, colonisation events, and cover, and negatively to disappearance events. Longer snow cover duration and rising temperatures were also related to increasing species numbers, but not to cover changes. The rapid biotic responses of Mediterranean alpine plants indicate a tight synchronisation with climate fluctuations, especially with water availability. Thus, it rather confirms concerns about biodiversity losses, if projections of increasing temperature in combination with decreasing precipitation hold true.

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