Seed dispersal effectiveness increases with body size in New Zealand alpine scree weta (<i>Deinacrida connectens</i>)

Larsen, Hannah; Burns, Kevin C.

doi:10.1111/j.1442-9993.2011.02340.x

Cited by 28 publications

(10 citation statements)

References 25 publications

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“…novae-zealandiae. However, other frugivores are known to consume eshy fruits in New Zealand, including some unusual seed dispersers such as reptiles (Wotton et al, 2016) and large orthopterans known as weta (Burns 2006;Duthie et al 2006;King et al 2011;Larsen and Burns 2012). Non-avian seed dispersers might disperse signi cant numbers of seeds across the elevation gradient.…”

Section: Discussionmentioning

confidence: 99%

Adaptive fruit colour variation along an elevational gradient in a colour-polymorphic plant

Lim

Burns

2022

Preprint

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Many plants produce colour polymorphic fruits. However, the processes responsible for the evolution and maintenance of fruit colour polymorphisms are poorly understood. We investigated the fruit colour polymorphism in Gaultheria depressa var. novae-zealandiae (Ericaceae), a predominantly bird-dispersed, alpine shrub from New Zealand, by testing whether colour morph frequencies vary geographically to maximise fruit-foliage colour contrasts. We also conducted a seed germination experiment to test whether fruit colour morphs vary in their susceptibility to UV damage. Results showed that ‘red’ fruits were more abundant at lower elevations, while ‘white’ fruits were predominant at higher elevations. Leaf colours shifted from ‘green’ in appearance at lower elevations to ‘red’ at higher elevations. Analyses of fruit-foliage colour contrasts showed that ‘red’ fruits were more conspicuous at lower elevations, and ‘white’ fruits being more conspicuous at higher elevations, which was consistent with the hypothesis that colour morph frequencies vary geographically to maximise their conspicuousness to dispersers. However, ‘red’ fruits were generally more conspicuous than ‘white’ fruits, regardless of elevation, indicating that the maintenance of the polymorphism could not be attributed to fruit-foliage colour contrasts alone. The seed germination experiment showed that ‘white’ fruits were more resistant to UV damage, suggesting the preponderance of ‘white’ fruited individuals in the landscape results from a greater degree of protection from UV damage. The fruit colour polymorphism in Gaultheria depressa var. novae-zealandiae therefore appears to be maintained by trade-offs between conspicuousness to dispersers and tolerance to UV damage, advocating a pluralistic approach to the problem in the future.

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Section: Discussionmentioning

confidence: 99%

Adaptive fruit colour variation along an elevational gradient in a colour-polymorphic plant

Lim

Burns

2022

Preprint

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“…age and stage). In the case of seed dispersal mutualism, for example, larger/older individuals may transport more seeds (Mũnoz and Bonal 2008, King et al 2011, Larsen and Burns 2012, Zwolak 2018). Yet, such high-resolution data are rarely available in other mutualisms.…”

Section: The Way Forwardmentioning

confidence: 99%

A perspective on stage‐structured mutualism and its community consequences

Nakazawa

2020

Oikos

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Ontogenetic variation is the most fundamental biological aspect of an organism, and stage‐structured (size‐structured) prey–predator relationships have increasingly been studied for better understanding food webs. However, little is known about stage‐structured mutualism and its community consequences (i.e. when and where it occurs and how it matters in community ecology). This article aims to argue that mutualism can be viewed as inherently stage‐structured while drawing research attention to the little‐studied issue. First, to conceptualize stage‐structured mutualism, I present possible community modules, such as inter‐stage partner sharing, ontogenetic antagonism–mutualism coupling and ontogenetic partner shift, which are mechanistically obtained due to the ontogenetic variation in associated costs and benefits. A synthesis of the literature across different mutualisms (e.g. pollination, seed dispersal, nutritional and defensive) demonstrates that mutualism is commonly stage‐structured, and those examples can be categorized into the different community modules conceptualized above. To integrate structural diversity and complexity, I present a general theoretical framework for describing community dynamics mediated by stage‐structured mutualism. It can provide testable hypotheses regarding how stage‐specific partners can affect each other through the life history of a shared host and how they jointly determine the lifetime fitness of the host. For the establishment of the ontogenetic perspective of mutualism, both empirical and theoretical efforts are needed to collect and incorporate individual‐level interaction data into community ecology theories, which will provide valuable insights not only into mutualism‐mediated community dynamics but also into biodiversity conservation and ecosystem management.

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“…Several species of Rhaphidophoridae (cave wētā), such as the iconic 'Mount Cook Flea' Pharmacus montanus, are also obligate alpine dwellers, found only in some of the highest alpine-nival zones of the Southern Alps (Richards 1972). Some wētā species, such as D. connectens and ground wētā Hemiandrus maculifrons, are thought to be seed dispersers of alpine plants (Burns 2006;Larsen & Burns 2012). However, the overall contribution of wētā to effective alpine seed dispersal is thought to be low (Morgan-Richards et al 2008;Young & Kelly 2014).…”

Section: Invertebratesmentioning

confidence: 99%

Impacts of introduced mammalian predators on New Zealand’s alpine fauna

O’Donnell¹,

Weston²,

Monks³

2017

NZ J Ecol

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Alpine zones are threatened globally by invasive species, hunting, and habitat loss caused by fire, anthropogenic development and climate change. These global threats are pertinent in New Zealand, with the least understood pressure being the potential impacts of introduced mammalian predators, the focus of this review. In New Zealand, alpine zones include an extensive suite of cold climate ecosystems covering c. 11% of the land mass. They support rich communities of indigenous invertebrates, lizards, fish, and birds. Many taxa are obligate alpine dwellers, though there is uncertainty about the extent to which distributions of some species are relicts of wider historical ranges. The impacts of introduced mammalian predators are well described in many New Zealand ecosystems, though little is known about the impacts of these predators on alpine fauna. Here we review the importance of alpine habitats for indigenous fauna and the impacts of introduced mammalian predators; and develop a conceptual model explaining threat interactions. Most evidence for predation is anecdotal or comes from studies of species with wider ranges and at lower altitudes. Nevertheless, at least ten introduced predator species have been confirmed as frequent predators of native alpine species, particularly among birds and invertebrates. In the case of the endangered takahe (Porphyrio hochstetteri) and rock wren (Xenicus gilviventris), stoats (Mustela erminea) are primary predators, which are likely to be impacting significantly on population viability. We also document records of mammalian predation on alpine lizards and freshwater fish. While the precise impacts on the long-term viability of threatened species have not been evaluated, anecdotal evidence suggests that predation by mammals is a serious threat, warranting predator control. Future research should focus on predicting when and where mammalian predators impact on populations of indigenous fauna, furthering our understanding of the alpine predator guild particularly through adaptive management experiments, and exploring interactions with other threats.

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Seed dispersal effectiveness increases with body size in New Zealand alpine scree weta (Deinacrida connectens)

Cited by 28 publications

References 25 publications

Adaptive fruit colour variation along an elevational gradient in a colour-polymorphic plant

Adaptive fruit colour variation along an elevational gradient in a colour-polymorphic plant

A perspective on stage‐structured mutualism and its community consequences

Impacts of introduced mammalian predators on New Zealand’s alpine fauna

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