scholarly journals Experimental species removals impact the architecture of pollination networks

2017 ◽  
Vol 13 (6) ◽  
pp. 20170243 ◽  
Author(s):  
Berry J. Brosi ◽  
Kyle Niezgoda ◽  
Heather M. Briggs
Keyword(s):  
Plant Species ◽  
Network Structure ◽  
Global Environmental Change ◽  
Simulation Models ◽  
Dynamic Responses ◽  
Resource Overlap ◽  
Flower Visitation ◽  
Resource Complementarity ◽  
Dietary Niche ◽  
Pollination Network

Mutualistic networks are key for the creation and maintenance of biodiversity, yet are threatened by global environmental change. Most simulation models assume that network structure remains static after species losses, despite theoretical and empirical reasons to expect dynamic responses. We assessed the effects of experimental single bumblebee species removals on the structure of entire flower visitation networks. We hypothesized that network structure would change following processes linking interspecific competition with dietary niche breadth. We found that single pollinator species losses impact pollination network structure: resource complementarity decreased, while resource overlap increased. Despite marginally increased connectance, fewer plant species were visited after species removals. These changes may have negative functional impacts, as complementarity is important for maintaining biodiversity–ecological functioning relationships and visitation of rare plant species is critical for maintaining diverse plant communities.

scholarly journals Mauritian coloured nectar no longer a mystery: a visual signal for lizard pollinators

2006 ◽  
Vol 2 (2) ◽  
pp. 165-168 ◽  
Author(s):  
Dennis M Hansen ◽  
Karin Beer ◽  
Christine B Müller
Keyword(s):  
Experimental Evidence ◽  
Plant Species ◽  
Flowering Plants ◽  
Visual Signal ◽  
Honest Signal ◽  
Endemic Plant ◽  
Floral Trait ◽  
Flower Visitation ◽  
Artificial Flowers ◽  
Endemic Plant Species

Most floral nectars are clear as water, and the enigmatic coloured nectar in three endemic plant species in Mauritius has puzzled scientists studying it. One hypothesis about the possible ecological function of coloured nectar is that it serves as a visual signal for pollinators. Recent studies have shown that at least two of the three Mauritian plant species with coloured nectar are visited and pollinated by endemic Phelsuma geckos. We here provide experimental evidence for the visual signal hypothesis by showing that Phelsuma ornata geckos prefer coloured over clear nectar in artificial flowers. In flowering plants, coloured nectar could additionally function as an honest signal that allows pollinators to assert the presence and judge the size of a reward prior to flower visitation, and to adjust their behaviour accordingly, leading to increased pollinator efficiency. Our study provides a first step in understanding this rare and intriguing floral trait.

scholarly journals Climate-human-environment interactions: resolving our past

2006 ◽  
Vol 2 (2) ◽  
pp. 187-203 ◽  
Author(s):  
J. A. Dearing
Keyword(s):  
Environmental Change ◽  
Spatial Scales ◽  
Global Environmental Change ◽  
Essential Element ◽  
Simulation Models ◽  
Alternative Methods ◽  
Human Society ◽  
Human Environment ◽  
The Past ◽  
Local Case

Abstract. The paper reviews how we can learn from the past about climate-human-environment interactions at the present time, and in the future. It focuses on data sources for environmental change at local/regional and regional/global spatial scales, and shows the scope and limitations of each. It reviews alternative methods for learning from the past, including the increasing use of simulation models. The use of multiple records (observational, palaeoenvironmental, archaeological, documentary) in local case-studies is exemplified in a study from China, where independent records help unravel the complexity of interactions and provide a basis for assessing the resilience and sustainability of the landscape system. Holocene global records for Natural Forcings (e.g. climate and tectonics), Human Society and Ecosystems are reviewed, and the problems of reconstructing global records of processes that are only recorded at local scales examined. Existing regional/global records are used to speculate about the veracity of anthropogenic forcing of global climate, with specific consideration of the Ruddiman theory. The paper concludes that a full understanding of causes of earth system change through (at least) the Holocene can come only through the most rigorous reconstructions of climate, human activities and earth processes, and importantly their interactions, at all locations and at all scales. It follows that we need to promote inter-scale learning: regionalisation and generalisation of existing data would be useful first steps. There is now a need to develop long-term simulation models that can help anticipate complex ecosystem behaviour and environmental processes in the face of global environmental change – and resolving our past is an essential element in that endeavour.

Pollination ecology of the dioecious tree Commiphora guillauminii in Madagascar

2004 ◽  
Vol 20 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Nina Farwig ◽  
Emile F. Randrianirina ◽  
Friederike A. Voigt ◽  
Manfred Kraemer ◽  
Katrin Böhning-Gaese
Keyword(s):  
Plant Species ◽  
Fruit Set ◽  
Pollen Limitation ◽  
Bird Species ◽  
Pollination Ecology ◽  
Floral Display ◽  
Flower Visitation ◽  
Visitation Rates ◽  
Male Flowers ◽  
Female Flowers

In dioecious plant species differences in morphology and resources between female and male flowers can have consequences for flower visitation rates. Female flowers sometimes lack pollen and can be less attractive to pollinators than male flowers. We studied the pollination ecology of the dioecious tree Commiphora guillauminii in a dry deciduous forest in western Madagascar. We recorded floral display, visiting insect species and visitation rates for female and male trees. The results showed that female trees produce significantly larger but fewer flowers per inflorescence than male ones. Number of flowers per tree did not differ between the sexes. During 270 observation-hours we observed 17 insect and two bird species visiting the flowers. Mean visitation rates of male flowers were 6.1 times higher than those of female flowers (1.07 vs. 0.18 visitors per flower h−1). Visitation rates to female and male trees showed similar daily and seasonal patterns. Fruit set (2.9%) was low, which could have been caused by pollinator or pollen limitation. This study suggests that dioecy may pose a risk for fruit set and, potentially, reproductive success for plant species with depauperate pollinator faunas on islands such as Madagascar.

scholarly journals Climate-human-environment interactions: resolving our past

2006 ◽  
Vol 2 (4) ◽  
pp. 563-604 ◽  
Author(s):  
J. A. Dearing
Keyword(s):  
Environmental Change ◽  
Global Climate ◽  
Spatial Scales ◽  
Global Environmental Change ◽  
Essential Element ◽  
Simulation Models ◽  
Human Society ◽  
Human Environment ◽  
Local Case ◽  
The Face

Abstract. The paper reviews how we can learn from the past about climate-human-interactions at the present time, and in the future. It focuses on data sources for environmental change at local and regional/global spatial scales, and shows the scope and limitations of each. The use of parallel histories in local case-studies is described in a case-study from China, where independent records help unravel the complexity of interactions and provide a basis for assessing the resilience and sustainability of the landscape system. Holocene global records for Natural Forcings (e.g. climate and tectonics), Human Society and Ecosystems are reviewed, and the problems of reconstructing global records of processes that are only recorded at local scales examined. Existing regional/global records are used to speculate about the veracity of anthropogenic forcing of global climate. The paper concludes that a full understanding of causes of earth system change through (at least) the Holocene can come only through the most rigorous reconstructions of climate, human activities and earth processes, and importantly their interactions, at all locations and at all scales. It follows that we need to promote inter-scale learning: regionalisation and generalisation of existing data would be useful first steps. There is now a need to develop long-term simulation models that can help anticipate complex ecosystem behaviour and environmental processes in the face of global environmental change – and resolving our past is an essential element in that endeavour.

scholarly journals Multitrophic higher-order interactions modulate species persistence

2021 ◽  
Author(s):  
Lisa Buche ◽  
Ignasi Bartomeus ◽  
Oscar Godoy
Keyword(s):  
Plant Species ◽  
Network Structure ◽  
Higher Order ◽  
Species Persistence ◽  
Pairwise Interactions ◽  
Species Pairs ◽  
Diverse Communities ◽  
Plant Persistence ◽  
Per Capita ◽  
Plant Pollinator

There is growing recognition that interactions between species pairs are modified in a multispecies context by the density of a third species. However, how these higher-order interactions (HOIs) affect species persistence remains poorly understood. To explore the effect of HOIs steaming from multiple trophic layers on plant persistence, we experimentally built a mutualistic system containing three plants and three pollinators species with two contrasting network structures. For both structures, we first estimated the statistically supported HOIs on plant species, in addition to the pairwise interactions among plants and plant-pollinators. Following a structuralist approach, we then assessed the effects of the supported HOIs on the persistence probability of each of the three competing plant species and their combinations. HOIs produced substantial effects on the strength and sign of per capita interactions between plant species to such an extent that predictions of species persistence differ from a non-HOIs scenario. Changes in network structure due to removing a plant-pollinator link further modulated the species persistence probabilities by reorganizing per capita interaction strengths of both pairwise interactions and HOIs. Our study provides empirical evidence of the joint importance of HOIs and network structure for determining the probability of species to persist within diverse communities.

Pollen loads and pollen diversity on bodies of Eulonchus tristis (Diptera: Acroceridae): implications for pollination and flower visitation

2008 ◽  
Vol 140 (2) ◽  
pp. 257-264 ◽  
Author(s):  
Christopher J. Borkent ◽  
Evert I. Schlinger
Keyword(s):  
Plant Species ◽  
Pollen Grains ◽  
Pollen Loads ◽  
Flower Visitation ◽  
Pollen Species ◽  
Plant Pollen

AbstractAcroceridae is a family of spider-parasitic flies that often visit flowers as adults, although little is known about their possible role as pollinators. Eulonchus tristis Loew visiting flowers of Brodiaea elegans Hoover (Liliaceae s.l.) and Iris douglasiana Herbert (Iridaceae) were collected in California. Individuals carried large pollen loads, although visitors to B. elegans carried significantly more pollen grains than visitors to I. douglasiana. Visitors to B. elegans also carried a higher percentage of focal-plant pollen (91%) than visitors to I. douglasiana (38%). There was no difference in the diversity of pollen species (approximately nine) carried by visitors to either plant species. For visitors to B. elegans, no difference was seen in the amount or diversity of pollen carried with respect to the sex of the visitor. The behaviour potentially resulting in the acquisition of these pollen loads is discussed. These results show that E. tristis has the potential to be an important pollinator for these plant species, particularly B. elegans.

A half-day flowering pattern helps plants sharing pollinators in an oceanic island community

2021 ◽  
pp. 1-10
Author(s):  
Xiangping Wang ◽  
Tong Zeng ◽  
Mingsong Wu ◽  
Dianxiang Zhang
Keyword(s):  
Plant Species ◽  
Flowering Plants ◽  
Oceanic Island ◽  
Species Level ◽  
Community Level ◽  
Flower Opening ◽  
Flower Visitation ◽  
Visitation Rates ◽  
Island Community ◽  
Plant Pollinator

Abstract The temporal pattern of flower opening and closure is a feature of the biology of many plant species, particularly those inhabiting oceanic islands where flowering generally lasts for only a few hours per day. Additionally, flower visitors often seek different floral sources on a timely basis, thus the relative timing of interactions is central to their status in pollination competition, or in the facilitation of pollination among co-flowering plants sharing pollinators. However, few studies have examined the impacts of daily temporal variation in flowering patterns on the pollinator network and competition on a community scale. In order to examine whether the daily pattern of flower opening and closure can impose temporal dynamics on interspecific interactions within a single day, plant–pollinator interaction networks (AM subweb and PM subweb) were quantified, and the relevant interactions between the two subwebs were compared using the Bray–Curtis dissimilarity of visitation frequencies in an oceanic island community (Paracel Islands, South China Sea). The role of species within networks and its variation between two subwebs were assessed by calculating the species-level specialization and species strength of each plant and pollinator species. The quantitative plant–pollinator interaction dissimilarity between morning and afternoon subsets was 0.69, and this value dropped to 0.58 when considering plant species flowering throughout the day. In our study, this dissimilarity between the two subwebs might be explained by the morning peak activity rather than a preference for morning flowers. No significant differences were detected in the species-level specialization and species strength of plants flowering all day from morning to afternoon at the community level. The flower visitation rates of native honeybee Apis cerana were not significantly different between morning and afternoon for most of the whole-day flowering plants. However, plant species only flowering either in the morning or the afternoon differed in the rate of visitation by A. cerana. The analyses of variation in the visitation rates of pollinators shared by plants within a single day in the studied community suggest that daily structuring at a community level and half-day staggered flowering during the morning or afternoon might reduce competitive interactions in oceanic insular habitats.

Sign in / Sign up

Export Citation Format

Share Document