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1.
PLoS One ; 14(12): e0225743, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31821341

RESUMO

Bees and the pollination services they deliver are beneficial to both food crop production, and for reproduction of many wild plant species. Bee decline has stimulated widespread interest in assessing hazards and risks to bees from the environment in which they live. While there is increasing knowledge on how the use of broad-spectrum insecticides in agricultural systems may impact bees, little is known about effects of other pesticides (or plant protection products; PPPs) such as herbicides and fungicides, which are used more widely than insecticides at a global scale. We adopted a systematic approach to review existing research on the potential impacts of fungicides and herbicides on bees, with the aim of identifying research approaches and determining knowledge gaps. While acknowledging that herbicide use can affect forage availability for bees, this review focussed on the potential impacts these compounds could have directly on bees themselves. We found that most studies have been carried out in Europe and the USA, and investigated effects on honeybees. Furthermore, certain effects, such as those on mortality, are well represented in the literature in comparison to others, such as sub-lethal effects. More studies have been carried out in the lab than in the field, and the impacts of oral exposure to herbicides and fungicides have been investigated more frequently than contact exposure. We suggest a number of areas for further research to improve the knowledge base on potential effects. This will allow better assessment of risks to bees from herbicides and fungicides, which is important to inform future management decisions around the sustainable use of PPPs.

2.
Food Chem ; 272: 66-75, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30309595

RESUMO

The composition of honey influences how beneficial it is to human health. This study evaluated the physiochemical properties and total phenolic content (TPC) of single vs. multi-floral Irish and selected international honeys, and whether properties varied according to hive location. Oilseed rape honey had the lowest TPC of Irish unifloral honeys. Heather honey had the highest TPC, similar to Manuka honey (Mean ±â€¯SD = 68.16 ±â€¯2.73 and 62.43 ±â€¯10.03 respectively), and the TPC of ivy honey was approximately half that of heather. Urban multi-floral honeys contained higher TPC (28.26 ±â€¯13.63) than rural honeys (20.32 ±â€¯11.54). Physiochemical properties varied according to floral origin, and whether hives were in urban or rural sites. Irish heather honey had similar physiochemical characteristics to Manuka honey. This first examination of Irish honey confirms that TPC and physiochemical properties vary with honey type and hive location, and suggests that Irish heather honey should be examined for potential health benefits.


Assuntos
Mel/análise , Fenóis/análise , Cor , Condutividade Elétrica , Ericaceae/química , Ericaceae/metabolismo , Flores/química , Flores/metabolismo , Fungos/isolamento & purificação , Mel/classificação , Mel/microbiologia , Concentração de Íons de Hidrogênio , Fenóis/química , Espectrofotometria , Açúcares/análise , Água/química , Leveduras/isolamento & purificação
3.
PeerJ ; 4: e2249, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27602260

RESUMO

Background. Pollinators, which provide the agriculturally and ecologically essential service of pollination, are under threat at a global scale. Habitat loss and homogenisation, pesticides, parasites and pathogens, invasive species, and climate change have been identified as past and current threats to pollinators. Actions to mitigate these threats, e.g., agri-environment schemes and pesticide-use moratoriums, exist, but have largely been applied post-hoc. However, future sustainability of pollinators and the service they provide requires anticipation of potential threats and opportunities before they occur, enabling timely implementation of policy and practice to prevent, rather than mitigate, further pollinator declines. Methods.Using a horizon scanning approach we identified issues that are likely to impact pollinators, either positively or negatively, over the coming three decades. Results.Our analysis highlights six high priority, and nine secondary issues. High priorities are: (1) corporate control of global agriculture, (2) novel systemic pesticides, (3) novel RNA viruses, (4) the development of new managed pollinators, (5) more frequent heatwaves and drought under climate change, and (6) the potential positive impact of reduced chemical use on pollinators in non-agricultural settings. Discussion. While current pollinator management approaches are largely driven by mitigating past impacts, we present opportunities for pre-emptive practice, legislation, and policy to sustainably manage pollinators for future generations.

5.
Environ Sci Pollut Res Int ; 23(7): 7050-4, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26856865

RESUMO

Potential detrimental impacts of neonicotinoids on non-target organisms, especially bees, have been subject to a wide debate and the subsequent ban of three neonicotinoids by the EU. While recent research has fortified concerns regarding the effects of neonicotinoids on ecosystem service (ES) providers, potential impacts have been considered negligible in systems with a relatively small proportion of arable land and thus lower the use of these pesticides. In this paper we argue that there is not sufficient information to assess magnitude and extent of neonicotinoid application, as well as potential non-target impacts on ES providers in grass-dominated systems with frequent land-use change. Using Ireland as an example, we show that the highly dynamic agricultural landscape, in conjunction with estimated persistence times of neonicotinoids in soils, may lead to a much larger area (18.6 ± 0.6% of the Irish agricultural area) exposed to these pesticides than initially assumed. Furthermore we present a number of important gaps in current research regarding the impacts of neonicotinoids on ES providers in such systems.


Assuntos
Exposição Ambiental/estatística & dados numéricos , Poluentes Ambientais/análise , Praguicidas/análise , Agricultura/estatística & dados numéricos , Animais , Abelhas , Ecossistema , Exposição Ambiental/análise , Irlanda , Solo
6.
Proc Natl Acad Sci U S A ; 113(1): 146-51, 2016 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-26621730

RESUMO

Wild and managed bees are well documented as effective pollinators of global crops of economic importance. However, the contributions by pollinators other than bees have been little explored despite their potential to contribute to crop production and stability in the face of environmental change. Non-bee pollinators include flies, beetles, moths, butterflies, wasps, ants, birds, and bats, among others. Here we focus on non-bee insects and synthesize 39 field studies from five continents that directly measured the crop pollination services provided by non-bees, honey bees, and other bees to compare the relative contributions of these taxa. Non-bees performed 25-50% of the total number of flower visits. Although non-bees were less effective pollinators than bees per flower visit, they made more visits; thus these two factors compensated for each other, resulting in pollination services rendered by non-bees that were similar to those provided by bees. In the subset of studies that measured fruit set, fruit set increased with non-bee insect visits independently of bee visitation rates, indicating that non-bee insects provide a unique benefit that is not provided by bees. We also show that non-bee insects are not as reliant as bees on the presence of remnant natural or seminatural habitat in the surrounding landscape. These results strongly suggest that non-bee insect pollinators play a significant role in global crop production and respond differently than bees to landscape structure, probably making their crop pollination services more robust to changes in land use. Non-bee insects provide a valuable service and provide potential insurance against bee population declines.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Insetos/fisiologia , Polinização , Animais , Formigas/fisiologia , Abelhas/fisiologia , Ecossistema , Flores/crescimento & desenvolvimento , Frutas/crescimento & desenvolvimento , Vespas/fisiologia
7.
Nature ; 521(7550): 74-76, 2015 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-25901684

RESUMO

The impact of neonicotinoid insecticides on insect pollinators is highly controversial. Sublethal concentrations alter the behaviour of social bees and reduce survival of entire colonies. However, critics argue that the reported negative effects only arise from neonicotinoid concentrations that are greater than those found in the nectar and pollen of pesticide-treated plants. Furthermore, it has been suggested that bees could choose to forage on other available flowers and hence avoid or dilute exposure. Here, using a two-choice feeding assay, we show that the honeybee, Apis mellifera, and the buff-tailed bumblebee, Bombus terrestris, do not avoid nectar-relevant concentrations of three of the most commonly used neonicotinoids, imidacloprid (IMD), thiamethoxam (TMX), and clothianidin (CLO), in food. Moreover, bees of both species prefer to eat more of sucrose solutions laced with IMD or TMX than sucrose alone. Stimulation with IMD, TMX and CLO neither elicited spiking responses from gustatory neurons in the bees' mouthparts, nor inhibited the responses of sucrose-sensitive neurons. Our data indicate that bees cannot taste neonicotinoids and are not repelled by them. Instead, bees preferred solutions containing IMD or TMX, even though the consumption of these pesticides caused them to eat less food overall. This work shows that bees cannot control their exposure to neonicotinoids in food and implies that treating flowering crops with IMD and TMX presents a sizeable hazard to foraging bees.


Assuntos
Abelhas/fisiologia , Dieta/veterinária , Preferências Alimentares , Inseticidas/análise , Néctar de Plantas/química , Animais , Abelhas/efeitos dos fármacos , Células Quimiorreceptoras/efeitos dos fármacos , Células Quimiorreceptoras/metabolismo , Feminino , Flores/química , Flores/efeitos dos fármacos , Preferências Alimentares/efeitos dos fármacos , Guanidinas/efeitos adversos , Guanidinas/análise , Guanidinas/farmacologia , Imidazóis/efeitos adversos , Imidazóis/análise , Imidazóis/farmacologia , Inseticidas/efeitos adversos , Inseticidas/farmacologia , Masculino , Neonicotinoides , Nitrocompostos/efeitos adversos , Nitrocompostos/análise , Nitrocompostos/farmacologia , Oxazinas/efeitos adversos , Oxazinas/análise , Oxazinas/farmacologia , Pólen/química , Polinização , Reprodução/efeitos dos fármacos , Reprodução/fisiologia , Análise de Sobrevida , Paladar/fisiologia , Tiametoxam , Tiazóis/efeitos adversos , Tiazóis/análise , Tiazóis/farmacologia
8.
PLoS One ; 10(3): e0119733, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25764085

RESUMO

Invasive alien plants can compete with native plants for resources, and may ultimately decrease native plant diversity and/or abundance in invaded sites. This could have consequences for native mutualistic interactions, such as pollination. Although invasive plants often become highly connected in plant-pollinator interaction networks, in temperate climates they usually only flower for part of the season. Unless sufficient alternative plants flower outside this period, whole-season floral resources may be reduced by invasion. We hypothesized that the cessation of flowering of a dominant invasive plant would lead to dramatic, seasonal compositional changes in plant-pollinator communities, and subsequent changes in network structure. We investigated variation in floral resources, flower-visiting insect communities, and interaction networks during and after the flowering of invasive Rhododendron ponticum in four invaded Irish woodland sites. Floral resources decreased significantly after R. ponticum flowering, but the magnitude of the decrease varied among sites. Neither insect abundance nor richness varied between the two periods (during and after R. ponticum flowering), yet insect community composition was distinct, mostly due to a significant reduction in Bombus abundance after flowering. During flowering R. ponticum was frequently visited by Bombus; after flowering, these highly mobile pollinators presumably left to find alternative floral resources. Despite compositional changes, however, network structural properties remained stable after R. ponticum flowering ceased: generality increased, but quantitative connectance, interaction evenness, vulnerability, H'2 and network size did not change. This is likely because after R. ponticum flowering, two to three alternative plant species became prominent in networks and insects increased their diet breadth, as indicated by the increase in network-level generality. We conclude that network structure is robust to seasonal changes in floral abundance at sites invaded by alien, mass-flowering plant species, as long as alternative floral resources remain throughout the season to support the flower-visiting community.


Assuntos
Flores/fisiologia , Insetos/fisiologia , Polinização , Rhododendron/fisiologia , Animais
9.
AoB Plants ; 72014 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-25527475

RESUMO

Populations of introduced species in their new environments are expected to differ from native populations, due to processes such as genetic drift, founder effects and local adaptation, which can often result in rapid phenotypic change. Such processes can also lead to changes in the genetic structure of these populations. This study investigated the populations of Rhododendron ponticum in its introduced range in Ireland, where it is severely invasive, to determine both genetic and flower width diversity and differentiation. We compared six introduced Irish populations with two populations from R. ponticum's native range in Spain, using amplified fragment length polymorphism and simple sequence repeat genetic markers. We measured flower width, a trait that may affect pollinator visitation, from four Irish and four Spanish populations by measuring both the width at the corolla tip and tube base (nectar holder width). With both genetic markers, populations were differentiated between Ireland and Spain and from each other in both countries. However, populations displayed low genetic diversity (mean Nei's genetic diversity = 0.22), with the largest proportion (76-93 %) of genetic variation contained within, rather than between, populations. Although corolla width was highly variable between individuals within populations, tube width was significantly wider (>0.5 mm) in introduced, compared with native, populations. Our results show that the same species can have genetically distinct populations in both invasive and native regions, and that differences in floral width may occur, possibly in response to ecological sorting processes or local adaptation to pollinator communities.

10.
Ecol Lett ; 17(11): 1389-99, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25167890

RESUMO

Co-flowering plant species commonly share flower visitors, and thus have the potential to influence each other's pollination. In this study we analysed 750 quantitative plant-pollinator networks from 28 studies representing diverse biomes worldwide. We show that the potential for one plant species to influence another indirectly via shared pollinators was greater for plants whose resources were more abundant (higher floral unit number and nectar sugar content) and more accessible. The potential indirect influence was also stronger between phylogenetically closer plant species and was independent of plant geographic origin (native vs. non-native). The positive effect of nectar sugar content and phylogenetic proximity was much more accentuated for bees than for other groups. Consequently, the impact of these factors depends on the pollination mode of plants, e.g. bee or fly pollinated. Our findings may help predict which plant species have the greatest importance in the functioning of plant-pollination networks.


Assuntos
Flores/genética , Magnoliopsida/genética , Filogenia , Polinização , Animais , Abelhas , Dípteros , Modelos Biológicos , Néctar de Plantas/química
11.
J Exp Biol ; 217(Pt 9): 1620-5, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-24526720

RESUMO

Bees visit flowers to collect nectar and pollen that contain nutrients and simultaneously facilitate plant sexual reproduction. Paradoxically, nectar produced to attract pollinators often contains deterrent or toxic plant compounds associated with herbivore defence. The functional significance of these nectar toxins is not fully understood, but they may have a negative impact on pollinator behaviour and health, and, ultimately, plant pollination. This study investigates whether a generalist bumblebee, Bombus terrestris, can detect naturally occurring concentrations of nectar toxins. Using paired-choice experiments, we identified deterrence thresholds for five compounds found in the nectar of bee-pollinated plants: quinine, caffeine, nicotine, amygdalin and grayanotoxin. The deterrence threshold was determined when bumblebees significantly preferred a sucrose solution over a sucrose solution containing the compound. Bumblebees had the lowest deterrence threshold for the alkaloid quinine (0.01 mmol l(-1)); all other compounds had higher deterrence thresholds, above the natural concentration range in floral nectar. Our data, combined with previous work using honeybees, suggest that generalist bee species have poor acuity for the detection of nectar toxins. The fact that bees do not avoid nectar-relevant concentrations of these compounds likely indicates that it is difficult for them to learn to associate floral traits with the presence of toxins, thus maintaining this trait in plant populations.


Assuntos
Abelhas/fisiologia , Comportamento Alimentar/fisiologia , Néctar de Plantas/química , Alcaloides/farmacologia , Amigdalina/farmacologia , Animais , Diterpenos/farmacologia
12.
PLoS One ; 9(1): e82996, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24421873

RESUMO

Declines in insect pollinators across Europe have raised concerns about the supply of pollination services to agriculture. Simultaneously, EU agricultural and biofuel policies have encouraged substantial growth in the cultivated area of insect pollinated crops across the continent. Using data from 41 European countries, this study demonstrates that the recommended number of honeybees required to provide crop pollination across Europe has risen 4.9 times as fast as honeybee stocks between 2005 and 2010. Consequently, honeybee stocks were insufficient to supply >90% of demands in 22 countries studied. These findings raise concerns about the capacity of many countries to cope with major losses of wild pollinators and highlight numerous critical gaps in current understanding of pollination service supplies and demands, pointing to a pressing need for further research into this issue.


Assuntos
Agricultura , Abelhas/fisiologia , Políticas , Polinização/fisiologia , Animais , Europa (Continente) , Geografia , Mel
13.
PLoS One ; 8(6): e65516, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23840338

RESUMO

The Bombus sensu stricto species complex is a widespread group of cryptic bumblebee species which are important pollinators of many crops and wild plants. These cryptic species have, until now, largely been grouped together in ecological studies, and so little is known about their individual colony densities, foraging ranges or habitat requirements, which can be influenced by land use at a landscape scale. We used mass-flowering oilseed rape fields as locations to sample bees of this complex, as well as the second most common visitor to oilseed rape B. lapidarius, and molecular RFLP methods to distinguish between the cryptic species. We then used microsatellite genotyping to identify sisters and estimate colony densities, and related both proportions of cryptic species and their colony densities to the composition of the landscape surrounding the fields. We found B. lucorum was the most common member of the complex present in oilseed rape followed by B. terrestris. B. cryptarum was also present in all but one site, with higher proportions found in the east of the study area. High numbers of bumblebee colonies were estimated to be using oilseed rape fields as a forage resource, with B. terrestris colony numbers higher than previous estimates from non-mass-flowering fields. We also found that the cryptic species responded differently to surrounding landscape composition: both relative proportions of B. cryptarum in samples and colony densities of B. lucorum were negatively associated with the amount of arable land in the landscape, while proportions and colony densities of other species did not respond to landscape variables at the scale measured. This suggests that the cryptic species have different ecological requirements (which may be scale-dependent) and that oilseed rape can be an important forage resource for many colonies of bumblebees. Given this, we recommend sustainable management of this crop to benefit bumblebees.


Assuntos
Abelhas/classificação , Brassica napus/fisiologia , Flores/crescimento & desenvolvimento , Análise de Sequência de DNA/métodos , Animais , Abelhas/genética , Abelhas/fisiologia , Produtos Agrícolas , Ecossistema , Comportamento Alimentar/fisiologia , Variação Genética , Repetições de Microssatélites , Polinização , Especificidade da Espécie
14.
PLoS One ; 7(5): e38073, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22666450

RESUMO

Parallel declines in insect-pollinated plants and their pollinators have been reported as a result of agricultural intensification. Intensive arable plant communities have previously been shown to contain higher proportions of self-pollinated plants compared to natural or semi-natural plant communities. Though intensive grasslands are widespread, it is not known whether they show similar patterns to arable systems nor whether local and/or landscape factors are influential. We investigated plant community composition in 10 pairs of organic and conventional dairy farms across Ireland in relation to the local and landscape context. Relationships between plant groups and local factors (farming system, position in field and soil parameters) and landscape factors (e.g. landscape complexity) were investigated. The percentage cover of unimproved grassland was used as an inverse predictor of landscape complexity, as it was negatively correlated with habitat-type diversity. Intensive grasslands (organic and conventional) contained more insect-pollinated forbs than non-insect pollinated forbs. Organic field centres contained more insect-pollinated forbs than conventional field centres. Insect-pollinated forb richness in field edges (but not field centres) increased with increasing landscape complexity (% unimproved grassland) within 1, 3, 4 and 5km radii around sites, whereas non-insect pollinated forb richness was unrelated to landscape complexity. Pollination systems within intensive grassland communities may be different from those in arable systems. Our results indicate that organic management increases plant richness in field centres, but that landscape complexity exerts strong influences in both organic and conventional field edges. Insect-pollinated forb richness, unlike that for non-insect pollinated forbs, showed positive relationships to landscape complexity reflecting what has been documented for bees and other pollinators. The insect-pollinated forbs, their pollinators and landscape context are clearly linked. This needs to be taken into account when managing and conserving insect-pollinated plant and pollinator communities.


Assuntos
Biodiversidade , Insetos/fisiologia , Agricultura Orgânica , Poaceae/classificação , Polinização , Animais , Indústria de Laticínios , Ecossistema , Poaceae/crescimento & desenvolvimento
16.
Biol Rev Camb Philos Soc ; 85(4): 777-95, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20184567

RESUMO

Global change may substantially affect biodiversity and ecosystem functioning but little is known about its effects on essential biotic interactions. Since different environmental drivers rarely act in isolation it is important to consider interactive effects. Here, we focus on how two key drivers of anthropogenic environmental change, climate change and the introduction of alien species, affect plant-pollinator interactions. Based on a literature survey we identify climatically sensitive aspects of species interactions, assess potential effects of climate change on these mechanisms, and derive hypotheses that may form the basis of future research. We find that both climate change and alien species will ultimately lead to the creation of novel communities. In these communities certain interactions may no longer occur while there will also be potential for the emergence of new relationships. Alien species can both partly compensate for the often negative effects of climate change but also amplify them in some cases. Since potential positive effects are often restricted to generalist interactions among species, climate change and alien species in combination can result in significant threats to more specialist interactions involving native species.


Assuntos
Mudança Climática , Insetos/fisiologia , Espécies Introduzidas , Desenvolvimento Vegetal , Polinização , Animais , Biodiversidade , Ecossistema
17.
Proc Biol Sci ; 276(1674): 3887-93, 2009 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-19692403

RESUMO

The structure of plant-pollinator networks has been claimed to be resilient to changes in species composition due to the weak degree of dependence among mutualistic partners. However, detailed empirical investigations of the consequences of introducing an alien plant species into mutualistic networks are lacking. We present the first cross-European analysis by using a standardized protocol to assess the degree to which a particular alien plant species (i.e. Carpobrotus affine acinaciformis, Impatiens glandulifera, Opuntia stricta, Rhododendron ponticum and Solanum elaeagnifolium) becomes integrated into existing native plant-pollinator networks, and how this translates to changes in network structure. Alien species were visited by almost half of the pollinator species present, accounting on average for 42 per cent of the visits and 24 per cent of the network interactions. Furthermore, in general, pollinators depended upon alien plants more than on native plants. However, despite the fact that invaded communities received more visits than uninvaded communities, the dominant role of alien species over natives did not translate into overall changes in network connectance, plant linkage level and nestedness. Our results imply that although supergeneralist alien plants can play a central role in the networks, the structure of the networks appears to be very permeable and robust to the introduction of invasive alien species into the network.


Assuntos
Ecossistema , Insetos/fisiologia , Plantas/classificação , Polinização/fisiologia , Animais , Europa (Continente)
18.
Conserv Biol ; 23(1): 184-95, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18798858

RESUMO

Fragmentation of natural habitats can increase numbers of rare species. Conservation of rare species requires experts and resources, which may be lacking for many species. In the absence of regular surveys and expert knowledge, historical sighting records can provide data on the distribution of a species. Numerous models have been developed recently to make inferences regarding the threat status of a taxon on the basis of variation in trends of sightings over time. We applied 5 such models to national and regional (county) data on 3 red-listed orchid species (Cephalanthera longifolia, Hammarbya paludosa, and Pseudorchis albida) and 1 species that has recently come to the attention of conservation authorities (Neotinea maculata) in the Republic of Ireland. In addition, we used an optimal linear estimate to calculate the time of extinction for each species overall and within each county. To account for bias in recording effort over time, we used rarefaction analysis. On the basis of sighting records, we inferred that these species are not threatened with extinction and, although there have been declines, there is no clear geographical pattern of decline in any species. Most counties where these orchid species occurred had a low number of sightings; hence, we were cautious in our interpretation of output from statistical models. We suggest the main drivers of decline in these species in Ireland are modification of habitats for increased agricultural production and lack of appropriate management. Our results show that the application of probabilistic models can be used even when sighting data are scarce, provided multiple models are used simultaneously and rarefaction is used to account for bias in recording effort among species over time. These models could be used frequently when making an initial conservation assessment of species in a region, particularly if there is a relatively constant recording rate and some knowledge of the underlying recording process. Regional-scale analyses, such as ours, complement World Conservation Union criteria for assessment of the extinct category and are useful for highlighting areas of under recording and focusing conservation efforts of rare and endangered species.


Assuntos
Conservação dos Recursos Naturais/métodos , Ecossistema , Modelos Estatísticos , Orchidaceae/fisiologia , Extinção Biológica , Irlanda , Dinâmica Populacional
19.
Ann Bot ; 104(3): 507-16, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18940852

RESUMO

BACKGROUND AND AIMS: Species may occur over a wide geographical range within which populations can display large variation in reproductive success and genetic diversity. Neotinea maculata is a rare orchid of conservation concern at the edge of its range in Ireland, where it occurs in small populations. However, it is relatively common throughout the Mediterranean region. Here, factors that affect rarity of N. maculata in Ireland are investigated by comparing Irish populations with those found in Italy, where it is more common. METHODS: Vegetation communities, breeding system and genetic diversity were compared using three amplified fragment length polymorphism (AFLP) primer pairs in populations in Ireland and Italy. Vegetation was quantified using quadrats taken along transects in study populations, and hand pollination experiments were performed to assess reliance of N. maculata on pollinators in both Irish and Italian populations. KEY RESULTS: Neotinea maculata occupies different vegetation communities in Italian and Irish populations. Breeding system experiments show that N. maculata is 100 % autogamous, and there are no differences in fruit and seed production in selfed, outcrossed and unmanipulated plants. AFLP markers revealed that Irish and Italian populations have similar genetic diversity and are distinct from each other. CONCLUSIONS: Neotinea maculata does not suffer any negative effects of autogamous reproduction; it self-pollinates and sets seed readily in the absence of pollinators. It occupies a variety of habitats in both Ireland and Italy; however, Irish populations are small and rare and should be conserved. This could be due to climatic factors and the absence of suitable soil mycorrhizas to allow recruitment from seed.


Assuntos
Ecossistema , Flores/genética , Variação Genética , Orchidaceae/genética , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Cruzamento , Flores/ultraestrutura , Geografia , Orchidaceae/ultraestrutura , Filogenia , Análise de Componente Principal , Solo
20.
Conserv Biol ; 22(2): 308-17, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18261149

RESUMO

To explain current plant invasions, or predict future ones, more knowledge on which factors increase the probability of alien species becoming naturalized and subsequently invasive is needed. We created a database of the alien plants in seminatural habitats in Ireland that included data on taxonomy, invasive status, invasion history, distribution, and biological and ecological plant characteristics. We used information from this database to determine the importance of these factors in increasing the ability of species to become naturalized and invasive. More specifically, we used two multiple logistic regressions to identify factors that distinguish naturalized from casual alien plant species and invasive from noninvasive, naturalized alien species. Clonal growth, moisture-indicator value, nitrogen-indicator value, native range, and date of first record affected (in order of decreasing importance) the probability of naturalization. Factors that distinguished invasive from noninvasive species were ornamental introduction, hermaphrodite flowers, pollination mode, being invasive elsewhere, onset of flowering season, moisture-indicator value, native range, and date of first record. Incorporation of phylogenetic information had little influence on the results, suggesting that the capacity of alien species to naturalize and become invasive evolved largely independently in several phylogenetic lineages. Whereas some of the variables were important for both transitions, others were only important for naturalization or for invasion. This emphasizes the importance of studying different stages of the invasion process when looking for mechanisms of becoming a successful invasive plant, instead of simply comparing invasive with noninvasive alien species. Our results also suggest that a combination of species traits and other variables is likely to produce the most accurate prediction of invasions.


Assuntos
Biodiversidade , Demografia , Ecossistema , Modelos Teóricos , Desenvolvimento Vegetal , Bases de Dados Factuais , Irlanda , Modelos Logísticos , Razão de Chances , Filogenia , Dinâmica Populacional
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