Influence Plant Species Diversity Research Articles

Discreet but diverse and specific: Determining plant‐herbivore interactions across a species‐rich plant family in a tropical rain forest

AbstractStudying plant–herbivore interactions within tropical rain forests is fundamental to understanding their ecology and evolution. An important aspect of plant–herbivore dynamics is the role of temporal and taxonomic variables in determining associations between herbivores and their host. Using the diverse and chemically rich plant family Annonaceae (Magnoliales), we conducted a year‐long study in Ecuador's Yasuní National Park in lowland Amazonia. We focused on nine understory tree species across a broad phylogenetic range within Annonaceae. For these species, we investigated patterns of herbivory, identified herbivores through DNA barcoding, and documented unique ant–butterfly associations. In general, leaf damage ranged from 0.09% to 25%, with significant temporal fluctuations for three species. Notably, Anaxagorea brevipes and Unonopsis veneficiorum faced higher herbivore pressure when compared to the other studied species. We document a discreet but diverse herbivore community, with 40 larvae from 12 Lepidoptera families collected throughout the year. Our findings identify, for the first time across a phylogenetically diverse sampling of Annonaceae, the specialization of herbivores on our focal species. Overall, our data provide valuable information on herbivory patterns at the local scale for this important rain forest plant family. Furthermore, these findings contribute to our understanding of the ecological processes that influence plant species diversity in tropical rain forests.Abstract in Spanish is available with online material.

Do farm size, age, and wealth status influence plant species diversity in homegarden agroforestry systems in southeastern Ethiopia?

Do farm size, age, and wealth status influence plant species diversity in homegarden agroforestry systems in southeastern Ethiopia?

Impacts of landscape patterns on plant species diversity at a global scale

Landscape patterns are important drivers of biodiversity. Owing to differences in vegetation types, sampling methods, diversity measures, spatial scales, and landscape levels, the impact of landscape patterns on biodiversity remains widely debated. Using a global standardized plant community database and land use and land cover maps at 30-m resolution, for the period 1990–2017, we calculated plant species α- and β-diversity, and landscape metrics at patch- and landscape-levels, and discerned the direct and indirect impacts of landscape patterns on plant species diversity based on environmental factors, namely climate, spatial features, and human disturbance. We found that landscape patterns exhibited the main indirect effects, whereas climate factors exhibited dominant direct effects on plant α-diversity via the direct effects of patch patterns and functional traits. With respect to β-diversity, landscape-level patterns exerted more direct than indirect effects. These effects are strongly dependent on scale. Landscape- and patch-level patterns had opposite effects on plant diversity, depending on their composition and spatial structure, demonstrating that their effects could be mediated by one another. The adaptation of plants to landscape patterns is mainly through variations in leaf area, plant height, specific leaf area, stem density, seed biomass, and other seed-dispersal traits, which vary across vegetation types. Our findings highlight the importance of functional traits and diversity in understanding the mechanism by which landscape patterns influence plant species diversity; accordingly, we recommend balancing the spatial structure of patch- and landscape-level patterns to enhance variation in functional traits, and, ultimately, to maintain global plant diversity.

Competitive size asymmetry, not intensity, is linked to species loss and gain in a native grassland community.

Competition is often highlighted as a major force influencing plant species diversity. However, there are multiple facets of competition (e.g., strength, intransitivity, and size asymmetry) that may have independent and differential impacts on diversity, making understanding the degree to which competition structures communities difficult. Unfortunately, field-based experiments that decouple multiple facets of competition are lacking, limiting our ability to test theoretical frameworks and reducing understanding of the actual linkages among competition and coexistence. Here, we experimentally manipulate the size structure of local grassland communities to examine the relative impacts of competitive size asymmetry (i.e., competitive advantage based on relative size) and intensity (i.e., mean effect of neighbors on plant growth) on species loss and gain. Increased competitive size asymmetry was associated with increased species loss and decreased species gain, while no relationship was found between competitive intensity and species loss and gain. Furthermore, the probability of loss was not dependent on a species initial size, suggesting that small species may not always be the losers of size-asymmetric interactions. Instead, loss was dependent on species rarity, where loss was higher for rare species. Overall, these results suggest that competitive size asymmetry may be more important for species loss than intensity in some plant communities and demonstrates the importance of decoupling different aspects of competition to better understand their drivers and ecological consequences.

Effect of Land Use Change on Wood Species Diversity, Carbon Stock and Implication for Sustainable Conservation of Biodiversity in Ethiopia

Land use-cover change (LULCC) is one of responsible with the anthropogenic activities that contribute the threat of biodiversity and the largest source of greenhouse gas emissions 12-20% in tropics and world that influence the human wellbeing and disturb functionality of ecosystem. The purpose of this review paper is to assess the LULCC causes, trends on forest land, consequences on plant species diversity and carbon stock and implications for sustainable landscape management in Ethiopia .Population growth, agricultural expansion, settlement, institutional factors, and weak policy enforcement and under value ecosystem were the main derivers of LULCC. At the regional, national and regional scales, these changes have profound influence plant species diversity and carbon stock potential for alterations of normal ecosystem function, particularly loss of plant biodiversity at genetic and species levels and rise of CO2 in atmosphere .the result of all these have direct impacts on livelihoods of local communities and sustainable development. Plant species diversity is reduced when land changed from a relatively undisturbed state to more intensive use. like farming, livestock grazing, selective tree harvesting, etc. while carbon stock also loss due to unsustainable agricultural land practice, conversion of native forest to agricultural land and less managed of degraded land.to revere this synergic conservation strategy is suggested like implement sustainable forest management and agricultural practice like agro-forestry.

What is the effect of 19 years of restoration managements on soil and vegetation on formerly improved upland grassland?

Finding the best management strategies to restore grassland diversity and achieve a compromise between agricultural use and biodiversity protection is a global challenge. This paper reports novel data relating to the impacts of 19 years of restoration managements predicted to increase botanical diversity within reseeded upland temperate grassland common in less favoured areas in Europe. The treatments imposed were: continuous sheep grazing, with and without lime application; hay cutting only, with and without lime application; hay cutting followed by aftermath grazing, with and without lime application; and a control treatment continuing the previous site management (liming, NPK application and continuous sheep grazing).Defoliation type, irrespective of liming, was the key driver influencing plant species diversity (hay cutting followed by aftermath grazing > hay cutting > grazing). Grazing only managements supported grasses at the expense of forbs, and thus related plant species diversity significantly declined. Limed treatments had higher concentrations of Ca and Mg in the soil compared to those receiving no lime. However, no effects on species richness or plant species composition were found. Potassium was the only element whose plant-available concentration in the soil tended to decrease in response to cutting treatments with herbage removal.Postponing the first defoliation to the middle of the growing season enables forbs to reach seed production, and this was the most effective restoration management option for upland grassland (as hay cutting only, and as hay cut followed by aftermath grazing). Although continuous low-density sheep grazing is often adopted as a means of improving floristic biodiversity, deleterious effects of this on plant diversity mean that it cannot be recommended as a means of long-term maintenance or restoration management of European temperate grasslands.

The Conservation of Osingnese Traditional Home Garden Agroforestry in Banyuwangi, East Java, Indonesia

Local culture and traditions have been considered as an important factor in influencing plant species diversity and composition of home garden, but their interactive effect have not yet been investigated. This research aimed to describe the plant species diversity in traditional home gardens, identify the species with important value based on ethnobotanical indices, and describe the perception of local people towards agroforestry conservation in Osingnese Villages in Banyuwangi. Data acquisition was performed at Kopen Dukuh, Buluhsari-Kopen Cungking, and Kemiren Villages. Floristic survey was implemented at 75 home gardens. An interview was implemented for each owner. Results showed that Osingnese home gardens consist of numerous plant species. Kopen Dukuh and Buluhsari-Kopen Cungking showed a complex structure which could be considered as a complex agroforestry. Cocos nucifera , Coffea canephora , Coffea liberica , Garcinia mangostana , and Durio zibethinus were the important species in complex agroforestry. Those species composition indicated that home gardens are able to conserve native plants of Malaysian regions, particularly Indonesian flora. Agroforestry knowledge was derived from the older generations and implemented in gardening practices. They also argued that recent agroforestry is an adaptation mechanism of land management. The government did not contribute to educate and empower local people about agroforestry practices.

Effects of grazing on plant species diversity and carbon partitioning in semiarid rangelands of northeastern China

Grasslands are one of the most widespread landscapes worldwide, covering approximately one-fifth of the world’s land surface, where grazing is a common practice. How carbon storage responds to grazing in steppes remains poorly understood. We quantified the effects of grazing on community composition and species diversity, and carbon storage in two typical grasslands of northeastern China, one in Horqin and the other one in Hulunbeier. In both grasslands, grazing did not influence plant species diversity. However, it substantially decreased above ground carbon by 31% and 54% in Horqin and Hulunbeier, respectively. Fenced and grazing treatments showed a similar belowground carbon at both locations. The predominant carbon pool in the study grassland ecosystem was found in the upper 100 cm soil depth, from 98.2 to 99.1% of the total carbon storage. There were no significant effects of grazing on soil carbon neither in the whole profile nor in the uppermost 20 cm soil depth inthe two study grasslands. Studies on the effects of varying rangeland management, such as region disparity and grazing systems, may have important consequences on species diversity and carbon partitioning, and thus on rangeland stability and ecosystem functioning.

Flora and factors affecting species diversity in the islet groups of the protected “Natura 2000” sites of the Amvrakikos Gulf and Mesolongi Lagoon (Ionian area, Greece)

Iliadou E., Panitsa M., Raus Th. & Dimopoulos P.: Flora and factors affecting species diversity in the islet groups of the protected “Natura 2000” sites of the Amvrakikos Gulf and Mesolongi Lagoon (Ionian area, Greece). — Willdenowia 44: 439–450. 2014. — Version of record first published online on 18 November 2014 ahead of inclusion in December 2014 issue; ISSN 1868-6397; © 2014 BGBM Berlin-Dahlem.DOI: http//dx.doi.org/10.3372/wi.44.44315The vascular plant species diversity of the islet groups in the Amvrakikos Gulf and Mesolongi Lagoon, hitherto unexplored, is documented by an inventory of vascular plants, filling gaps in the floristic information available for the two National Parks to which these islet groups belong, as well as for the Ionian land-bridge island system for which detailed studies concerning floristic and phytogeographical relationships were available before. The total vascular flora of the two islet groups comprises 226 plant taxa. Spectra of life-form and chorological elements are presented and discussed. Floristic cross-correlations (beta-diversity) show that the individual islet floras differ from each other from 39 % to 91 %. Concerning the role of eco-geographical variables as influencing plant species diversity in the area, regression analyses indicate island area as the major predictor variable of species richness.

Comparing the two Greek archipelagos plant species diversity and endemism patterns highlight the importance of isolation and precipitation as biodiversity drivers.

BackgroundGreece has two island archipelagos, the Aegean and the Ionian, which host a rich array of plants and wildlife, particularly endemic and threatened plant species. Despite the long history of island biogeographic studies in the Aegean, similar studies in the Ionian remain limited, with the two island archipelagos rarely being compared.ResultsThe Aegean and Ionian archipelagos share many features, especially regarding total plant diversity, but exhibit different patterns of endemism. For instance, when considering similarly sized islands, those in the Ionian host as many as, if not more, species compared to the Aegean. In contrast, the Ionian Islands are poor in endemics (particularly narrow range endemics, such as single island or regional endemics) and threatened taxa, compared to the Aegean Islands. In the Ionian, endemics only persist on the largest islands, and form a very small proportion of the species pool, compared to the Aegean archipelago.ConclusionsThe lack of endemism might be attributed to the more recent separation of the Ionian Islands from the mainland and the shorter distance separating them from the mainland. In addition, the Ionian Islands receive higher levels of precipitation and are typically covered by denser and higher vegetation than the Aegean Islands. These conditions favour greater total species richness, but tend to lead to higher numbers of common species compared to threatened and endemic taxa. This study demonstrates that both isolation and precipitation serve as biodiversity drivers, influencing plant species diversity and endemism patterns, of the two Greek archipelagos.Electronic supplementary materialThe online version of this article (doi:10.1186/2241-5793-21-16) contains supplementary material, which is available to authorized users.

Flora and factors affecting species diversity in protected “Natura 2000” sites of the Ionian area: the Echinades islet group (Greece)

Iliadou E., Panitsa M., Raus Th. & Dimopoulos P.: Flora and factors affecting species diversity in protected “Natura 2000” sites of the Ionian area: the Echinades islet group (Greece). — Willdenowia 44: 121–136. 20 March 2014. — Version of record published online ahead of inclusion in April 2014 issue; ISSN 1868-6397; © 2014 BGBM Berlin-Dahlem.DOI: http//dx.doi.org/10.3372/wi.44.44113The vascular plant species diversity of the Echinades islet group, quite unexplored so far, is documented by an inventory of flowering plants and ferns, filling a gap in the floristic information available for the National Park to which these islets belong, as well as for the Ionian land-bridge island system, for which detailed studies concerning floristic and phytogeographical relationships were available before. Field investigations on 19 of the 20 Echinades islets generated an inventory of plant species composition for the first time for 18 of them and added 56 taxa as new to the islet of Oxeia as compared to previous literature. The total vascular flora of the Echinades islets comprises 386 plant taxa. Spectra of life-form and chorological categories are presented and discussed. Floristic cross-correlations (beta-diversity) showed that the individual islet floras differ from each other from 25 % to 85 %. Concerning the role of geographical variables as influencing plant species diversity in the area, regression analyses indicated island surface area and elevation as the major predictor variables of species richness, while distance to the mainland plays a subordinate predictive role.

Trait‐mediated effect of arbuscular mycorrhiza on the competitive effect and response of a monopolistic species

Summary 1. Cessation of agricultural practices often leads to a dramatic decline in species diversity concomitant with the increase in abundance of monopolistic species, which have been hypothesized to be strongly arbuscular mycorrhiza (AM) dependent. AM can affect competitive interactions and influence plant species diversity. Few studies have tested AM effects on the competitive strategy of monopolistic species although it has been shown to be a key parameter to explain their high dominance. In addition, it is not clear whether AM effects on plant interactions can be explained by density‐mediated interactions or by trait‐mediated interactions. 2. We measured the competitive effect of Festuca paniculata, a widespread monopolistic species from subalpine communities, on itself and on two additional target species with and without AM (benomyl treatment) under contrasted fertilised treatments. AM effects on target species traits were quantified. 3. The three target species exhibited contrasted AM dependency and only F. paniculata was positively affected by AM presence in fertilised conditions. In the fertilised treatment, AM decreased intra‐specific competition and increased inter‐specific competition. Changes in competitive responses were explained by the AM effect on P inflow and species lateral spread. 4. Our results highlight AM ability to modify the performance of monopolistic species under different environmental conditions. AM provide an important mechanism by which monopolistic species can maintain a high level of dominance and dramatically decrease species diversity following agricultural abandonment.

Fire frequency and tree canopy structure influence plant species diversity in a forest-grassland ecotone

Disturbances and environmental heterogeneity are two factors thought to influence plant species diversity, but their effects are still poorly understood in many ecosystems. We surveyed understory vegetation and measured tree canopy cover on permanent plots spanning an experimental fire frequency gradient to test fire frequency and tree canopy effects on plant species richness and community heterogeneity within a mosaic of grassland, oak savanna, oak woodland, and forest communities. Species richness was assessed for all vascular plant species and for three plant functional groups: grasses, forbs, and woody plants. Understory species richness and community heterogeneity were maximized at biennial fire frequencies, consistent with predictions of the intermediate disturbance hypothesis. However, overstory tree species richness was highest in unburned units and declined with increasing fire frequency. Maximum species richness was observed in unburned units for woody species, with biennial fires for forbs, and with near-annual fires for grasses. Savannas and woodlands with intermediate and spatially variable tree canopy cover had greater species richness and community heterogeneity than old-field grasslands or closed-canopy forests. Functional group species richness was positively correlated with functional group cover. Our results suggest that annual to biennial fire frequencies prevent shrubs and trees from competitively excluding grasses and prairie forbs, while spatially variable shading from overstory trees reduces grass dominance and provides a wider range of habitat conditions. Hence, high species richness in savannas is due to both high sample point species richness and high community heterogeneity among sample points, which are maintained by intermediate fire frequencies and variable tree canopy cover.

Seasonal reversals of upland‐riparian diversity gradients in the Sonoran Desert

ABSTRACTFlood disturbance and water resource availability vary sharply over time and space along arid‐region rivers and can interact in complex fashion to shape diversity patterns. Plant diversity showed spatial patterning along a topogradient from the floodplain of the San Pedro River (Arizona, USA) to the arid upland, but the patterns shifted temporally as the suite of limiting factors changed. During two of three sampling times, spatial diversity patterns were shaped primarily by gradients of water availability, the regional limiting factor. In the summer dry season, microscale diversity (species richness per 1 m2) and mesoscale diversity (cumulative species and functional types in 20, 1‐m2 plots) of herbaceous plants decreased along the topogradient from floodplain to upland, reflecting the greater water availability on the low surfaces. During a summer wet season with moderate rains and flooding, diversity increased in all hydrogeomorphic zones (floodplain, terrace, upland), but the spatial pattern along the topogradient persisted. Following a very wet winter, patterns along the topogradient reversed: scour from large floods limited diversity on the floodplain and competitive exclusion limited the diversity on undisturbed river terrace, while abundant rains allowed for high microscale diversity in the upland. Disturbance and resource availability thus interacted to influence plant species diversity in a fashion consistent with the dynamic‐equilibrium model of species diversity. In contrast to the microscale patterns, mesoscale diversity of species and functional types remained high in the floodplain during all sampling times, with 58% more plant species and 90% more functional types sampled in low floodplain than arid upland for the year as a whole. Species with a wide range of moisture and temperature affinities were present in the floodplain, and seasonal turnover of species was high in this zone. The floodplain zone of a perennial to intermittent‐flow river thus had greater plant diversity than arid Sonoran Desert upland, as measured at temporal scales that capture seasonal variance in resource and disturbance pulses and at spatial scales that capture the environmental heterogeneity of floodplains. Although periodically limited by intense flood disturbance, diversity remains high in the floodplain because of the combination of moderate resource levels (groundwater, seasonal flood water) and persistent effects of flood disturbance (high spatial heterogeneity, absence of competitive exclusion), in concert with the same climatic factors that produce seasonally high diversity in the region (temporally variable pulses of rainfall).

Grazing management effects on plant species diversity in tallgrass prairie

A 6-year study was conducted in tallgrass prairie to assess the effects of grazing management (cattle stocking densities and grazing systems) on plant community composition and diversity. Treatments included sites grazed season-long (May to October) at 3 stocking densities (3.8, 2.8, and 1.8 hectares per animal unit), ungrazed control sites, and sites under a late-season rest rotation grazing system at this same range of stocking densities. Plant communities were sampled twice each season using a nearest-point procedure. Native plant species diversity, species richness, and growth form diversity were significantly higher in grazed compared to ungrazed prairie, and diversity was greatest at the highest stocking density. This enhancement of plant species diversity under grazing was not a result of increased frequency of weedy/exotic species. There were no significant effects of grazing system on plant diversity, nor any significant stocking density × grazing system interactions, indicating that animal density is a key management variable influencing plant species diversity and composition in tallgrass prairie and that effects of animal density override effects of grazing systems. Increasing cattle stocking densities decreased the abundance of the dominant perennial tall grasses, and increased abundance of the C4 perennial mid-grasses. The frequency of perennial forbs was relatively stable across grazing treatments. Abundance of annual forbs varied among years and grazing treatments. In half of the years sampled, annual forbs showed the highest frequency under intermediate stocking density. Patterns of responses among plant groups suggest that some species may respond principally to direct effects of grazers and others may respond to indirect effects of grazers on competitive relationships or on the spatial patterns of fuel loads and fires. Thus, this study suggests that large grazer densities, fire, and annual climatic variability interact to influence patterns of plant community composition and diversity in tallgrass prairie. Effects of varying management such as stocking densities and grazing systems on plant species diversity and the relative abundances of different plant growth forms or functional groups may have important consequences for grassland community stability and ecosystem function.

Grazing management effects on plant species diversity in tallgrass prairie

A 6-year study was conducted in tallgrass prairie to assess the effects of grazing management (cattle stocking densities and grazing systems) on plant community composition and diversity. Treatments included sites grazed season-long (May to October) at 3 stocking densities (3.8, 2.8, and 1.8 hectares per animal unit), ungrazed control sites, and sites under a late-season rest rotation grazing system at this same range of stocking densities. Plant communities were sampled twice each season using a nearest-point procedure. Native plant species diversity, species richness, and growth form diversity were significantly higher in grazed compared to ungrazed prairie, and diversity was greatest at the highest stocking density. This enhancement of plant species diversity under grazing was not a result of increased frequency of weedy/exotic species. There were no significant effects of grazing system on plant diversity, nor any significant stocking density × grazing system interactions, indicating that animal density is a key management variable influencing plant species diversity and composition in tallgrass prairie and that effects of animal density override effects of grazing systems. Increasing cattle stocking densities decreased the abundance of the dominant perennial tall grasses, and increased abundance of the C4 perennial mid-grasses. The frequency of perennial forbs was relatively stable across grazing treatments. Abundance of annual forbs varied among years and grazing treatments. In half of the years sampled, annual forbs showed the highest frequency under intermediate stocking density. Patterns of responses among plant groups suggest that some species may respond principally to direct effects of grazers and others may respond to indirect effects of grazers on competitive relationships or on the spatial patterns of fuel loads and fires. Thus, this study suggests that large grazer densities, fire, and annual climatic variability interact to influence patterns of plant community composition and diversity in tallgrass prairie. Effects of varying management such as stocking densities and grazing systems on plant species diversity and the relative abundances of different plant growth forms or functional groups may have important consequences for grassland community stability and ecosystem function.