Introduced deer and the pollination and reproduction of an animal-pollinated herb

We evaluated the hypothesis that the modified population density of Aquilegia formosa Fisch. ex DC. (Ranunculaceae) resulting from the introduction of Sitka black-tailed deer ( Odocoileus hemionus sitkensis ) in the Haida Gwaii archipelago affects the pollination and reproductive performance of this herbaceous species. We compared the population density, pollination, and reproductive success of A. formosa among three small islands colonized by deer and three deer-free islands. Islands with deer had a substantially lower absolute density and a greater relative density of A. formosa than deer-free islands. The presence of deer was associated with higher pollen deposition, which probably resulted from the greater relative density of A. formosa on islands with deer. However, the presence of deer had no significant effect on individual reproductive success. The latter result is likely a consequence of the lack of pollen limitation in this species, as well as of the conflicting relationship between the absolute and relative densities of A. formosa and the presence of deer.

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Short-term effects of hunting on naïve black-tailed deer (Odocoileus hemionus sitkensis): behavioural response and consequences on vegetation growth

Canadian Journal of Zoology ◽

10.1139/cjz-2014-0122 ◽

2014 ◽

Vol 92 (11) ◽

pp. 915-925 ◽

Cited By ~ 10

Author(s):

Soizic Le Saout ◽

Sophie Padié ◽

Simon Chamaillé-Jammes ◽

Simon Chollet ◽

Steve Côté ◽

...

Keyword(s):

Odocoileus Hemionus ◽

Control Area ◽

Behavioural Response ◽

Haida Gwaii ◽

Short Term ◽

Nonconsumptive Effects ◽

Vegetation Growth ◽

Marine Subsidies ◽

Odocoileus Hemionus Sitkensis ◽

Bait Stations

Hunting is commonly used to reduce overabundant deer populations that are of socioeconomic and ecological concerns. Recently, it has been suggested that “hunting for fear” might help maximize nonconsumptive effects of hunting and their cascading impacts. We investigated how a predator-free black-tailed deer (Odocoileus hemionus sitkensis Merriam, 1898) population introduced to the Haida Gwaii archipelago (Canada) responded to short-term hunting for fear. We conducted a hunt that minimized killing and maximized scaring on an island where some deer were marked. Between control and hunted sites, we compared deer use of bait stations and of shoreline areas (i.e., an open and risky area that provided marine subsidies). We also compared the browsing pressure and growth of two grasses and two shrubs. Hunting for fear had no effect on the overall use of bait stations and shorelines. However, in the area exposed to hunting, unmarked deer, which were assumed to be less tolerant of human disturbance, avoided bait stations at the outset of hunting. We concluded that individuals perceive and respond to risk differently. Furthermore, two of the four plant species were less likely to be browsed and had better growth in the experimental area than in the control area, suggesting an indirect effect of hunting on plants mediated by deer behaviour.

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Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole Microtus Montanus

The UW National Parks Service Research Station Annual Reports ◽

10.13001/uwnpsrc.2005.3607 ◽

2005 ◽

Vol 29 ◽

pp. 49-51

Author(s):

Alita Pinter

Keyword(s):

Population Dynamics ◽

Reproductive Success ◽

Population Density ◽

Climatic Factors ◽

Small Rodents ◽

Microtus Montanus ◽

Small Measure ◽

Long Term Studies

A variety of hypotheses has been proposed to explain multiannual fluctuations in population density ("cycles") of small rodents (for reviews see Finerty 1980, Taitt and Krebs 1985). Doubtless, such cycles - known since antiquity (Elton 1942) - result from an interaction of a multitude of factors. However, the inability of extant hypotheses, alone or in combination, to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon.

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Do abundance and proximity of the alien Impatiens glandulifera affect pollination and reproductive success of two sympatric co-flowering native species?

Journal of Pollination Ecology ◽

10.26786/1920-7603(2012)16 ◽

2012 ◽

Vol 10 ◽

pp. 130-139

Author(s):

Valérie Cawoy ◽

Mathieu Jonard ◽

Carolin Mayer ◽

Anne-Laure Jacquemart

Keyword(s):

Reproductive Success ◽

Native Species ◽

Natural Populations ◽

Pollen Deposition ◽

Impatiens Glandulifera ◽

Insect Behaviour ◽

Native Flora ◽

Visitation Rates ◽

Aconitum Napellus ◽

Negative Effect

In invasion ecology, potential impacts of aliens on native flora are still under debate. Our aim was to determine the pollinator mediated effects of both proximity and abundance of an alien species on the reproductive success of natives. We chose the highly invasive Impatiens glandulifera and two native species: Epilobium angustifolium and Aconitum napellus ssp. lusitanicum. These species share characteristics allowing for pollination interactions: similar biotopes, overlapping flowering periods and same main pollinators. The effects of abundance (5, 25 and 100 individuals) and proximity (0 and 15 m) of the alien on visitation rate, insect behaviour, pollen deposition and reproductive success of both natives were investigated during 2 flowering seasons. We used centred visitation rates as they can be directly interpreted as a positive or negative effect of the invasive.Both abundance and proximity of the alien increased bumblebee visitation rates to both natives. On the other hand, abundance of the exotic species had a slight negative effect on honeybee visits to natives while its proximity had no effect. The behaviour of bumblebees changed as visitors left significantly more often the native plants for I. glandulifera when its abundance increased. As a consequence of this “inconstancy”, bees deposited considerable quantities of alien pollen on native stigmas. Nevertheless, this interspecific pollen transfer did not decrease seed set in natives. Self-compatibility and high attractiveness of both native species probably alleviate the risk of altered pollinator services and reproductive success due to the invader in natural populations.

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Balancing selection maintains polymorphisms at neurogenetic loci in field experiments

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1621228114 ◽

2017 ◽

Vol 114 (14) ◽

pp. 3690-3695 ◽

Cited By ~ 23

Author(s):

Eija Lonn ◽

Esa Koskela ◽

Tapio Mappes ◽

Mikael Mokkonen ◽

Angela M. Sims ◽

...

Keyword(s):

Reproductive Success ◽

Population Density ◽

Arginine Vasopressin ◽

Field Experiments ◽

Balancing Selection ◽

Regulatory Region ◽

Natural Populations ◽

Myodes Glareolus ◽

Sexual Antagonism ◽

Reproductive Behaviors

Most variation in behavior has a genetic basis, but the processes determining the level of diversity at behavioral loci are largely unknown for natural populations. Expression of arginine vasopressin receptor 1a (Avpr1a) and oxytocin receptor (Oxtr) in specific regions of the brain regulates diverse social and reproductive behaviors in mammals, including humans. That these genes have important fitness consequences and that natural populations contain extensive diversity at these loci implies the action of balancing selection. In Myodes glareolus, Avpr1a and Oxtr each contain a polymorphic microsatellite locus located in their 5′ regulatory region (the regulatory region-associated microsatellite, RRAM) that likely regulates gene expression. To test the hypothesis that balancing selection maintains diversity at behavioral loci, we released artificially bred females and males with different RRAM allele lengths into field enclosures that differed in population density. The length of Avpr1a and Oxtr RRAMs was associated with reproductive success, but population density and the sex interacted to determine the optimal genotype. In general, longer Avpr1a RRAMs were more beneficial for males, and shorter RRAMs were more beneficial for females; the opposite was true for Oxtr RRAMs. Moreover, Avpr1a RRAM allele length is correlated with the reproductive success of the sexes during different phases of reproduction; for males, RRAM length correlated with the numbers of newborn offspring, but for females selection was evident on the number of weaned offspring. This report of density-dependence and sexual antagonism acting on loci within the arginine vasopressin–oxytocin pathway explains how genetic diversity at Avpr1a and Oxtr could be maintained in natural populations.

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Heterospecific pollen deposition is positively associated with reproductive success in a diverse hummingbird‐pollinated plant community

Oikos ◽

10.1111/oik.08714 ◽

2021 ◽

Author(s):

Sabrina Aparecida Lopes ◽

Pedro Joaquim Bergamo ◽

Steffani Najara Pinho Queiroz ◽

Jeff Ollerton ◽

Thiago Santos ◽

...

Keyword(s):

Reproductive Success ◽

Plant Community ◽

Pollen Deposition ◽

Heterospecific Pollen ◽

Heterospecific Pollen Deposition

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A comparison of density estimation methods in plateau pika populations in an alpine meadow ecosystem

Journal of Mammalogy ◽

10.1093/jmammal/gyaa049 ◽

2020 ◽

Vol 101 (4) ◽

pp. 1091-1096

Author(s):

Wanrong Wei ◽

Jundong He ◽

Qiaoyan Zheng ◽

Yuli He ◽

Maria K Oosthuizen

Keyword(s):

Population Density ◽

Relative Density ◽

Alpine Meadow ◽

Survey Methods ◽

Estimation Methods ◽

Plateau Pika ◽

Relative Population ◽

Burrow Density ◽

The Absolute ◽

Absolute Population

Abstract Plateau pikas are a keystone species and ecosystem engineers in alpine meadow ecosystems. A number of surveying methods have been used to estimate pika density, but the reliability of these methods is not known. In addition, better population density methodologies allow for more reliable density estimates. We therefore compared the relationship among several commonly used methods of estimating pika relative density and the absolute density (AD) of pika populations. This relationship was investigated in summer and winter pastures to determine whether distribution pattern of the pikas (patchy or uniform) would influence this relationship. During August of 2015 and August of 2016, we measured the relative and absolute population density of pikas in an alpine meadow in the County, Gansu province, northwestern China. Relative density was measured with three indirect and direct methods: the total burrow density (TBD), the active burrow density (ABD), and the direct counting density (DCD) at the peak of pika activity. AD was assessed by removal sampling. Our results showed that the relative population density with all three survey methods was significantly related to the absolute population density. In particular, DCD at the peak of the pika activity showed the best correlation with AD. A simple linear model showed the effect of grazing time by livestock had a significant effect on TBD and ABD. These results imply that using DCD as a method to survey at the peak of the pika activity is more reliable than other methods.

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Linking pollinator efficiency to patterns of pollen limitation: small bees exploit the plant–pollinator mutualism

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.0635 ◽

2018 ◽

Vol 285 (1880) ◽

pp. 20180635 ◽

Cited By ~ 18

Author(s):

Matthew H. Koski ◽

Jennifer L. Ison ◽

Ashley Padilla ◽

Angela Q. Pham ◽

Laura F. Galloway

Keyword(s):

Pollen Limitation ◽

Pollen Deposition ◽

Pollinator Efficiency ◽

Flower Visitation ◽

Female Phase ◽

Male Phase ◽

Single Flower ◽

Floral Visitation ◽

Low Efficiency ◽

Plant Pollinator

Seemingly mutualistic relationships can be exploited, in some cases reducing fitness of the exploited species. In plants, the insufficient receipt of pollen limits reproduction. While infrequent pollination commonly underlies pollen limitation (PL), frequent interactions with low-efficiency, exploitative pollinators may also cause PL. In the widespread protandrous herb Campanula americana , visitation by three pollinators explained 63% of the variation in PL among populations spanning the range. Bumblebees and the medium-sized Megachile campanulae enhanced reproductive success, but small solitary bees exacerbated PL. To dissect mechanisms behind these relationships, we scored sex-specific floral visitation, and the contributions of each pollinator to plant fitness using single flower visits. Small bees and M. campanulae overvisited male-phase flowers, but bumblebees frequently visited female-phase flowers. Fewer bumblebee visits were required to saturate seed set compared to other bees. Scaling pollinator efficiency metrics to populations, small bees deplete large amounts of pollen due to highly male-biased flower visitation and infrequent pollen deposition. Thus, small bees reduce plant reproduction by limiting pollen available for transfer by efficient pollinators, and appear to exploit the plant–pollinator mutualism, acting as functional parasites to C. americana . It is therefore unlikely that small bees will compensate for reproductive failure in C. americana when bumblebees are scarce.

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