scholarly journals Pollinator importance networks illustrate the crucial value of bees in a highly speciose plant community

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Gavin Ballantyne ◽  
Katherine C. R. Baldock ◽  
Luke Rendell ◽  
P. G. Willmer
Keyword(s):  
Plant Species ◽  
Community Level ◽  
Taxonomic Resolution ◽  
Pollen Deposition ◽  
Pollinator Effectiveness ◽  
Flower Visitors ◽  
Pollinator Importance ◽  
Visitation Frequency ◽  
Pollinator Performance ◽  
Number Of Plant Species

AbstractAccurate predictions of pollination service delivery require a comprehensive understanding of the interactions between plants and flower visitors. To improve measurements of pollinator performance underlying such predictions, we surveyed visitation frequency, pollinator effectiveness (pollen deposition ability) and pollinator importance (the product of visitation frequency and effectiveness) of flower visitors in a diverse Mediterranean flower meadow. With these data we constructed the largest pollinator importance network to date and compared it with the corresponding visitation network to estimate the specialisation of the community with greater precision. Visitation frequencies at the community level were positively correlated with the amount of pollen deposited during individual visits, though rarely correlated at lower taxonomic resolution. Bees had the highest levels of pollinator effectiveness, with Apis, Andrena, Lasioglossum and Osmiini bees being the most effective visitors to a number of plant species. Bomblyiid flies were the most effective non-bee flower visitors. Predictions of community specialisation (H2′) were higher in the pollinator importance network than the visitation network, mirroring previous studies. Our results increase confidence in existing measures of pollinator redundancy at the community level using visitation data, while also providing detailed information on interaction quality at the plant species level.

scholarly journals Contrasting pollination efficiency and effectiveness among flower visitors of Malva sylvestris, Borago officinalis and Onobrychis viciifolia

2017 ◽  
Vol 21 ◽  
Author(s):  
Anna Gorenflo ◽  
Tim Diekötter ◽  
Mark Van Kleunen ◽  
Volkmar Wolters ◽  
Frank Jauker
Keyword(s):  
Plant Species ◽  
Pollen Deposition ◽  
Pollinator Effectiveness ◽  
Borago Officinalis ◽  
Flower Visitor ◽  
Flower Visitors ◽  
Onobrychis Viciifolia ◽  
Single Visit ◽  
Malva Sylvestris ◽  
Visitation Frequency

Biotic pollination is an important factor for ecosystem functioning and provides a substantial ecosystem service to human food security. Not all flower visitors are pollinators, however, and pollinators differ in their pollination performances. In this study, we determined the efficiencies of flower visitors to the plant species Malva sylvestris, Borago officinalis and Onobrychis viciifolia by analysing stigmatic pollen deposition. We further calculated pollinator effectiveness by scaling up single-visit pollen deposition using visitation frequency. Flower-visitor groups differed in their efficiencies at the single-visit level and not all of them deposited more pollen compared to unvisited stigmas. Bumblebees tended to be most efficient in depositing pollen per single visit across the three plant species. Due to the by far highest visitation frequencies, Apis mellifera showed the highest effectiveness in depositing pollen per hour for M. sylvestris and B. officinalis, but not for O. viciifolia, for which the Bombus lapidarius complex was both the most frequent and the most effective pollinator group. Hence, the most frequent flower visitors were most effective in our study. For non-dominant pollinator groups, however, visitation frequencies contributed disproportionally to pollinator effectiveness. Thus, combining pollen deposition per single-visit with visitation frequency is necessary to reveal true pollinator performance and to better understand flower-visitor interactions. 

Effects of climate on pollination networks in the West Indies

2009 ◽  
Vol 25 (5) ◽  
pp. 493-506 ◽  
Author(s):  
Ana M. Martín González ◽  
Bo Dalsgaard ◽  
Jeff Ollerton ◽  
Allan Timmermann ◽  
Jens M. Olesen ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Plant Species ◽  
West Indies ◽  
Relative Importance ◽  
The West ◽  
Pollinator Importance ◽  
Insect Pollinator ◽  
Pollinator Species ◽  
Plant Pollinator ◽  
Number Of Plant Species

Abstract:We studied the effect of climate on the plant-pollinator communities in the West Indies. We constructed plots of 200 m × 5 m in two distinct habitats on the islands of Dominica, Grenada and Puerto Rico (total of six plots) and recorded visitors to all plant species in flower. In total we recorded 447 interactions among 144 plants and 226 pollinator species. Specifically we describe how rainfall and temperature affect proportional richness and importance of the different pollinator functional groups. We used three measures of pollinator importance: number of interactions, number of plant species visited and betweenness centrality. Overall rainfall explained most of the variation in pollinator richness and relative importance. Bird pollination tended to increase with rainfall, although not significantly, whereas insects were significantly negatively affected by rainfall. However, the response among insect groups was more complex; bees were strongly negatively affected by rainfall, whereas dipterans showed similar trends to birds. Bird, bee and dipteran variation along the climate gradient can be largely explained by their physiological capabilities to respond to rainfall and temperature, but the effect of climate on other insect pollinator groups was more obscure. This study contributes to the understanding of how climate may affect neotropical plant-pollinator communities.

scholarly journals Frequency of flower visitors and achene production increase with rising population size in the self-incompatible herb Centaurea scabiosa (Asteraceae)

Plant Ecology ◽  
2021 ◽  
Vol 222 (5) ◽  
pp. 613-623
Author(s):  
Stefan Abrahamczyk ◽  
Mirjam Thielen ◽  
Maximilian Weigend
Keyword(s):  
Population Size ◽  
Plant Species ◽  
Clonal Plant ◽  
Current Status ◽  
Small Populations ◽  
Flower Visitors ◽  
Local Populations ◽  
Flower Visitation ◽  
Visitation Frequency ◽  
Achene Production

AbstractSelf-incompatible, non-clonal plant species are especially dependent on the activity of flower visitors for seed production. Therefore, populations of these plants are vulnerable to a reduced flower visitation rates, but also to increased isolation by extinction of local populations. To study how local populations of Centaurea scabiosa, a self-incompatible, bee-pollinated herb species changed over time in the region of Bonn, we collected historical population records in the area and investigated their current status. We found that more than half of the subpopulations mentioned in the literature between 1950 and 2012 (38 of 65) have since disappeared. Small populations were most vulnerable, whereas medium to large populations increased in size. In a second step, we studied visitation frequencies and achene production and weight across 14 extant populations. We found that both flower visitation frequency and achene production were positively related to population size. Achene weight was neither related to the frequency of flower visitors nor to achene production. These results clearly indicate that reduced pollen transfer and lower pollination rates may contribute to local extinction in small populations of Centaurea scabiosa. Overall our results call for an intensified monitoring of the populations of self-incompatible plant species.

scholarly journals Constructing more informative plant–pollinator networks: visitation and pollen deposition networks in a heathland plant community

2015 ◽  
Vol 282 (1814) ◽  
pp. 20151130 ◽  
Author(s):  
G. Ballantyne ◽  
Katherine C. R. Baldock ◽  
P. G. Willmer
Keyword(s):  
Food Security ◽  
Plant Community ◽  
Interaction Networks ◽  
Pollen Deposition ◽  
Pollinator Effectiveness ◽  
Pollinator Importance ◽  
Visit Frequency ◽  
Low Diversity ◽  
Pollination Systems ◽  
Plant Pollinator

Interaction networks are widely used as tools to understand plant–pollinator communities, and to examine potential threats to plant diversity and food security if the ecosystem service provided by pollinating animals declines. However, most networks to date are based on recording visits to flowers, rather than recording clearly defined effective pollination events. Here we provide the first networks that explicitly incorporate measures of pollinator effectiveness (PE) from pollen deposition on stigmas per visit, and pollinator importance (PI) as the product of PE and visit frequency. These more informative networks, here produced for a low diversity heathland habitat, reveal that plant–pollinator interactions are more specialized than shown in most previous studies. At the studied site, the specialization index was lower for the visitation network than the PE network, which was in turn lower than for the PI network. Our study shows that collecting PE data is feasible for community-level studies in low diversity communities and that including information about PE can change the structure of interaction networks. This could have important consequences for our understanding of threats to pollination systems.

scholarly journals Pollen tube growth from multiple pollinator visits more accurately quantifies pollinator performance and plant reproduction

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jamie R. Stavert ◽  
Charlie Bailey ◽  
Lindsey Kirkland ◽  
Romina Rader
Keyword(s):  
Pollen Tube ◽  
Seed Production ◽  
Plant Species ◽  
Pollen Tube Growth ◽  
Plant Reproduction ◽  
Tube Growth ◽  
Pollen Deposition ◽  
Pollen Quality ◽  
Single Visit ◽  
Pollinator Performance

Abstract Pollination services from animals are critical for both crop production and reproduction in wild plant species. Accurately measuring the relative contributions of different animal taxa to pollination service delivery is essential for identifying key pollinators. However, widely used measures of pollinator effectiveness (e.g., single visit pollen deposition) may be inaccurate where plant reproduction is strongly constrained by pollen quality. Here, we test the efficacy of single and multiple pollinator visits for measuring pollinator performance in a model plant species (apple, Malus domestica Borkh) that is strongly limited by pollen quality. We determined pollination success using a suite of measures (pollen deposition, pollen tube growth, fruit and seed set) from single and multiple pollinator visits. We found that pollen deposition from a single pollinator visit seldom resulted in the growth of pollen tubes capable of eliciting ovule fertilisation and never resulted in fruit or seed production. In contrast, multiple pollinator visits frequently initiated the growth of pollen tubes capable of ovule fertilisation and often led to fruit and seed production. Our findings suggest that single visit pollen deposition may provide a poor measure of pollinator performance when linked to reproductive success of plant species that are constrain by pollen quality. Alternatively, pollen tube growth from single and multiple pollinator visits can provide a measure of pollinator performance that is more closely linked to plant reproduction.

Numbers of plant species on the islands of Aldabra Atoll

1979 ◽  
Vol 286 (1011) ◽  
pp. 247-254 ◽  
Keyword(s):  
Plant Species ◽  
Woody Plants ◽  
Mixed Model ◽  
Common Species ◽  
Small Island ◽  
Island Ecosystems ◽  
Species Numbers ◽  
Island Effect ◽  
Species Area ◽  
Number Of Plant Species

The logarithm of island area accounts for 70 % of the variance in the number of plant species occurring on 100 lagoon islands. Two components of island altitude (altitude of the island rim and the logarithm of the island’s inland altitude) are also of importance, and account for 9 % of the variation in species numbers. A further 13 variables account for only an extra 5 % of the variance in the mixed model. These results resemble the findings of other island studies. In the equation S = K A z , z = 0.345 and falls within the range of expected values. The species-area curve gives little indication of the ‘small island effect’ found for other small islands; this may reflect, among other factors, the richness of the Aldabran flora when compared with those of the small island ecosystems already studied. The curve is also compared with that compiled by Williams (1964) and a discrepancy between the two is discussed. Woody plants are largely responsible for the increase of species numbers with increasing area. Species that are restricted to islands of particular sizes are listed and the characteristics of the frequencies of occurrence of the more common species are summarized.

scholarly journals SPECIES DIVERSITY, UTILIZATION AND CONSERVATION IN HOME GARDENS OF SOME RESIDENTIAL AREAS, COIMBATORE, INDIA.

2015 ◽  
Vol 2 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Jamuna S ◽  
Subhasree R ◽  
Karthika K ◽  
Paulsamy S ◽  
Thenmozhi K
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Ocimum Basilicum ◽  
Home Gardens ◽  
The Other ◽  
Home Garden ◽  
Residential Areas ◽  
Important Species ◽  
Celosia Cristata ◽  
Number Of Plant Species

The present study was aimed at documenting species composition, utilization and conservation of plant species growing in home gardens of 10 residential areas of Coimbatore city, India. Household interviews and home garden surveys revealed that all the 109 plant species included in 60 families included have someeconomic uses or with ornamental significance. Higher number of species was herbs followed by shrubs, trees, climbers, succulent herbs, vines and sub-shrubs. The families viz., Asteraceae, Apocynaceae and Acanthaceae contributed higher number of plant species than the other families to the home gardens. Thespecies namely, Celosia cristata, Chrysanthemum odoratum and Ocimum basilicum have registered 50% frequency among the home gardens sampled which indicates that these species have distributed and maintained in comparatively higher number of home gardens. The home garden species are mainly under thecategories of vegetables, fruits, ornamentals, economic important species and medicinal. These results further report revealed that homegardens satisfy various household needs like food, ornamentals, medicines, building material, religious and ceremonial uses.

scholarly journals The relationship between resource abundance and insect herbivory on islands

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256183
Author(s):  
Bora Shin ◽  
Jae-Young Lee ◽  
Nang-Hee Kim ◽  
Sei-Woong Choi
Keyword(s):  
Plant Species ◽  
Forest Cover ◽  
Food Resource ◽  
Phytophagous Insects ◽  
Feeding Guild ◽  
Resource Abundance ◽  
Variable Effect ◽  
The Relationship ◽  
External Feeding ◽  
Number Of Plant Species

We examined the relationship between resource abundance and the feeding activity of phytophagous insects on three common island plants. The aim was to investigate the correlation between phytophagous insects’ abundance and availability of food and island geography. We collected 30,835 leaves from three tree species groups (Mallotus japonicus, Prunus species, and Quercus species) on 18 islands in southwest Korea. The number of plant resources for herbivores varied: the number of leaves per shoot was the highest in Mallotus, leaf weight and the water content per leaf was significantly lower in Quercus species. External feeding was higher for Prunus and Quercus species, whereas the internal feeding type was significantly higher for Quercus species. Geography (area and distance), elevation and food resource (elevation, number of plant species, and the forest cover rate) had a variable effect on phytophagous insects feeding activities: distance and the number of plant species were more explainable to the external feeding guild. In contrast, area and forest cover were more to the internal feeding guild.

scholarly journals Attraction of flower visitors to plants that express indirect defence can minimize ecological costs of ant–pollinator conflicts

2010 ◽  
Vol 26 (5) ◽  
pp. 555-557 ◽  
Author(s):  
Johnattan Hernández-Cumplido ◽  
Betty Benrey ◽  
Martin Heil
Keyword(s):  
Plant Species ◽  
Extrafloral Nectaries ◽  
Food Sources ◽  
Extrafloral Nectar ◽  
Indirect Defence ◽  
Flower Visitors ◽  
Antagonistic Interactions

Thousands of plant species throughout tropical and temperate zones secrete extrafloral nectar (EFN) (see www.biosci.unl.edu/emeriti/keeler/extrafloral/worldlistfamilies.htm) to attract ants, whose presence leads to an indirect defence against herbivores (Chamberlain & Holland 2009, Heil 2008, Heil & McKey 2003, Rico-Gray & Oliveira 2007). Although termed ‘extrafloral’ because the nectar is not involved in pollination, EFN can also be secreted within the inflorescences (Bentley 1977, Holland et al. 2010, Martins 2009). Because ants tend to defend reliable food sources against all types of putative competitors, it has been hypothesized that the presence of extrafloral nectaries close to flowers may lead to competition among ants and pollinators, or even to direct ant–pollinator conflicts. Such antagonistic interactions would reduce the access of pollinators to flowers and, thereby, may cause significant ‘ecological costs’ of indirect, ant-mediated defences (Heil 2002).

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