Seed Dispersal Distances by Ants Increase in Response to Anthropogenic Disturbances in Australian Roadside Environments
TL;DR: Investigating the extent to which dispersal services by ants are influenced by anthropogenic disturbances associated with roadwork activities in southern NSW, Australia shows that myrmecochory is an unevenly diffuse mutualism, where few ant species contributed to much of the dispersal of seeds.
Abstract: Ants provide a common dispersal vector for a variety of plants in many environments through a process known as myrmecochory. The efficacy of this dispersal mechanism can largely determine the ability of species to track changes in habitat availability caused by ongoing land-use and associated disturbances, and can be critical for population gene flow and persistence. Field studies were conducted in a typical fragmented agricultural landscape in southern NSW, Australia, to investigate the extent to which dispersal services by ants are influenced by anthropogenic disturbances associated with roadwork activities (i.e. soil disturbance as the result of grading of roads). Observational experiments were performed in road segments that were divided into disturbed and non-disturbed zones, where Acacia pycnantha seeds were offered at multiple bait stations and monitored. For combined species, the mean dispersal distance recorded in the disturbed zone (12.2m) was almost double that recorded in the non-disturbed zone (5.4m) for all roadside sites. Our findings show that myrmecochory is an unevenly diffuse mutualism, where few ant species contributed to much of the dispersal of seeds. Iridomyrmex purpureus was responsible for all seed dispersal distances > 17m, where a maximum of 120m in disturbed, versus 69m in non-disturbed zones, was recorded. Rhytidoponera metallica and Melophorus bruneus were important seed dispersers in non-disturbed and disturbed zones, respectively. In general, large bodied ants tended to move more seeds to longer distances in disturbed zones, as opposed to non-disturbed zones, where smaller bodied species carried out a greater percentage of short distance dispersals (< 1m). We also recorded secondary dispersal events from nests by I. purpureus, a phenomenon previously not quantified. Infrequent, long distance dispersal to suitable sites may be highly important for seedling recruitment in disturbed or modified habitats in otherwise highly fragmented rural environments.
Citations
More filters
TL;DR: In this paper, the authors synthesize the existing literature on zoochory in urban environments and place the findings in the context of ecosystem dynamics, and assess the ecological and evolutionary consequences for seed dispersal following urbanization by considering how Zoochory is affected by specific features of urban environments.
Abstract: The increasing urban sprawl has contributed to the extensive fragmentation and reduction of natural habitat worldwide. Urbanization has a range of adverse effects on ecosystem functioning, including the disruption of plant dispersal processes across the landscape. Urban fragmentation can alter the distance and directionality of dispersal, leading to disrupted gene flow among populations. The dispersal processes of plants that rely on animal-mediated dispersal (zoochory) may be disproportionately affected by urbanization, as many animals avoid urban areas or restrict their movements within urban habitats. This could alter the efficiency of animal dispersal vectors and modify seed movements across urban habitats. While recent studies suggest that seed dispersal networks can be complex and dynamic even in highly managed green areas with relatively low biodiversity, zoochory in urban environments remains understudied. We synthesize the existing literature on zoochory in urban environments and place the findings in the context of ecosystem dynamics. We assess the ecological and evolutionary consequences for seed dispersal following urbanization by considering how zoochory is affected by specific features of urban environments. These include the complexity of habitats with varying continuity; high disturbance and intense management; a high proportion of alien species combined with low natural biodiversity; animal behavioral adjustments in different urban settings; and rapid evolutionary change due to urbanization. We conclude that 1) urbanization can disrupt and alter zoochory processes; and 2) successful zoochory can, in turn, alleviate or worsen the challenges to ecosystem dynamics originating from increased urbanization. The dynamic urban seed dispersal networks are emerging as useful models for the adaptability of seed dispersal communities. Their study can also shed light on eco-evolutionary processes under anthropogenic selective pressures, including species interactions. Finally, urban zoochory processes are critical to the functioning of urban ecosystems and as such, constitute an important ecosystem service with management implications. We propose directions for further research into urban zoochory processes to ensure the maintenance of ecosystem dynamics as urbanization continues.
24 citations
9 citations
TL;DR: The role of vascular plants as a potential surrogate for the diversity of ants and carabid beetles has been tested, investigating the influence of the environmental variables (dead wood, litter, anthropic disturbance, bare soil, bedrocks and rocks) on these relationships as mentioned in this paper.
8 citations
TL;DR: Using morphological and genetic data, a multilocus phylogeny with outgroups demonstrates that Nilopegamys is sister to Colomys, and the status of four other taxa currently recognized within ColomYS goslingi are reviewed and it is demonstrated that these names lack phylogenetic and/or morphological support.
8 citations
TL;DR: The effect of disturbance on the abundance, richness, and composition of ant communities and the resulting seed‐dispersal services for a herbaceous myrmecochore, Corydalis giraldii (Papaveraceae), in an undisturbed habitat, moderately disturbed habitat, and highly disturbed habitat (road verge) on Qinling Mountains, China is investigated.
Abstract: Anthropogenic habitat disturbance has potential consequences for ant communities. However, there is limited information on the effects of ant responses on associated ecological processes such as seed dispersal. We investigated the effect of disturbance on the abundance, richness, and composition of ant communities and the resulting seed‐dispersal services for a herbaceous myrmecochore, Corydalis giraldii (Papaveraceae), in an undisturbed habitat (forest understory), moderately disturbed habitat (abandoned arable field), and highly disturbed habitat (road verge) on Qinling Mountains, China. In total, we recorded 13 ant species, and five out of these were observed to transport seeds. The community composition of dispersers was significantly different amongst habitats. The richness of the dispersers did not differ among the habitats, but their total abundance varied significantly across habitats and was 21% lower in the road verge than in the abandoned arable fields. The major seed‐dispersing ant species in both the forest understory and the abandoned arable field were large‐bodied (Myrmica sp. and Formica fusca, respectively), whereas the major seed‐dispersing ants found in the road verge were the small‐bodied Lasius alienus. This difference resulted in lower seed removal rates and dispersal distances in the road verge than in the other two habitats. The different dispersal patterns were attributed primarily to differences in dispersing ant abundance and identity, most likely in response to habitats with different degree of anthropogenic disturbance. The possible influence of disturbance on the ecological specialization of ant‐seed dispersal interaction is also discussed.
5 citations
References
More filters
Journal Article•
TL;DR: Copyright (©) 1999–2012 R Foundation for Statistical Computing; permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and permission notice are preserved on all copies.
Abstract: Copyright (©) 1999–2012 R Foundation for Statistical Computing. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the R Core Team.
272,030 citations
"Seed Dispersal Distances by Ants In..." refers methods in this paper
...All statistical tests were carried out using R statistical software (R Development Core Team, 2013)....
[...]
TL;DR: Road density and network structure are informative landscape ecology assays and Australia has huge road-reserve networks of native vegetation, whereas the Dutch have tunnels and overpasses perforating road barriers to enhance ecological flows.
Abstract: A huge road network with vehicles ramifies across the land, representing a surprising frontier of ecology. Species-rich roadsides are conduits for few species. Roadkills are a premier mortality source, yet except for local spots, rates rarely limit population size. Road avoidance, especially due to traffic noise, has a greater ecological impact. The still-more-important barrier effect subdivides populations, with demographic and probably genetic consequences. Road networks crossing landscapes cause local hydrologic and erosion effects, whereas stream networks and distant valleys receive major peak-flow and sediment impacts. Chemical effects mainly occur near roads. Road networks interrupt horizontal ecological flows, alter landscape spatial pattern, and therefore inhibit important interior species. Thus, road density and network structure are informative landscape ecology assays. Australia has huge road-reserve networks of native vegetation, whereas the Dutch have tunnels and overpasses perforating road barriers to enhance ecological flows. Based on road-effect zones, an estimated 15‐20% of the United States is ecologically impacted by roads.
2,949 citations
"Seed Dispersal Distances by Ants In..." refers background in this paper
...Nevertheless, disturbances often occur in such environments, which can both demote or promote species, depending on the frequency and intensity of given disturbance regimes (e.g., Forman and Alexander, 1998)....
[...]
TL;DR: Together with the development and refinement of mathematical models, this promises a deeper, more mechanistic understanding of dispersal processes and their consequences.
Abstract: Growing interest in spatial ecology is promoting new approaches to the study of seed dispersal, one of the key processes determining the spatial structure of plant populations. Seed-dispersion patterns vary among plant species, populations and individuals, at different distances from parents, different microsites and different times. Recent field studies have made progress in elucidating the mechanisms behind these patterns and the implications of these patterns for recruitment success. Together with the development and refinement of mathematical models, this promises a deeper, more mechanistic understanding of dispersal processes and their consequences.
1,884 citations
"Seed Dispersal Distances by Ants In..." refers background in this paper
...Plants use various strategies to disperse their propagules into new habitats, such as by wind, water, vertebrate or ants (van der Pijl, 1982; Nathan and Muller-Landau, 2000)....
[...]
TL;DR: This chapter discusses the evolution of Dispersal Organs in General, and discusses the role of dispersal strategy and the Biocoenosis in this process.
Abstract: I. Introduction.- A. The Place of Dispersal in the Chain of Life.- B. Limitations and Objections.- C. History and General Literature.- II. General Terminology.- III. The Units of Dispersal.- Vegetative Parts in Dispersal and False Vivipary.- IV. The Relation Between Flowers, Seeds and Fruits.- A. Seed and Fruit.- B. Morphological Fruit Systems.- C. Morphological Interaction Between Fruit and Flower.- 1. General.- 2. Position.- 3. Monovuly and Monospermy.- 4. Inferiority and the Calyx.- D. Inadequacy of Current Fruit Terminology.- V. Ecological Dispersal Classes, Established on the Basis of the Dispersing Agents.- A. General.- B. Invertebrates.- C. Fishes and Ichthyochory.- D. Reptiles and Saurochory.- E. Birds and Ornithochory.- 1. Epizoochory by Birds.- 2. Synzoochorous Bird Diaspores.- 3. Endozoochory.- Non-adapted Diaspores.- Adapted Diaspores.- The Syndrome of Bird Diaspores.- Oil-containing Fruits.- Remarks on Evolution.- Mimesis (Imitative Seeds).- F. Mammals and Mammaliochory.- 1. General.- 2. Dyszoochory and Rodents.- 3. Accidental Endozoochory.- 4. Adaptive Endozoochory.- Ungulates.- Bats and Chiropterochory.- Primates.- Various Mammals.- G. Ants and Myrmecochory.- H. Wind and Anemochory.- 1. General.- 2. Dust Diaspores.- 3. Balloons.- 4. Plumed (Comose) Diaspores.- 5. Winged Diaspores.- 6. Tumbleweeds.- 7. Wind-Ballists (Anemoballists).- J. Water and Hydrochory.- 1. General.- 2. Rain Wash (Ombrohydrochory).- 3. Rain-Ballists.- 4. Submerged Transport in Water.- 5. Floating Diaspores.- K. Epizoochory, Transport on the Outside of Animals in General.- 1. Diverse Origins.- 2. Trample Burrs.- 3. Water Burrs.- 4. Burrs and Other Adhesives Above Ground Level.- 5. Other Spiny Fruits.- L. Autochory, Dispersal by the Plant Itself.- 1. General.- 2. Active Ballists.- 3. Passive Ballists.- 4. Creeping Diaspores.- M. Barochory, Dispersal by Weight Only.- N. Retrospective View.- VI. Dispersal Strategy and the Biocoenosis.- A. Atelochory.- 1. General.- 2. Synaptospermy.- 3. Basicarpy.- 4. Geocarpy.- B. Polychory and Attendant Phenomena.- 1. General.- 2. Heterodiaspory.- 3. Tachyspory.- C. Concluding Remarks on Synecology.- 1. Deserts.- 2. The Rain Forest.- 3. Epiphytes.- 4. The Arctic.- 5. Island Floras.- 6. Plant Sociology and Dispersal.- 7. Coordinated Dispersal.- VII. Establishment.- A. General.- B. Fixation.- C. Vivipary.- D. Germination.- 1. General Importance.- 2. Span of Life and Dormancy.- 3. Influence of Dispersing Agents and Other Stimuli.- VIII. The Evolution of Dispersal Organs in General.- A. Aims.- B. Isosporous Pteridophytes.- C. Heterosporous Pteridophytes with Free Megaspores.- D. Pteridosperms.- E. Gymnosperms (or Pre-Angiosperms).- F. Angiosperms.- 1. The Seed.- 2. The Seed Escaped from Angiospermy.- 3. The Sarcotesta Maintained in Conventional Fruits.- 4. Arilloids.- 5. Pulpa.- 6. The Pericarp Fruit.- Shift of Function.- Autonomous Cycles.- Further Evolutionary Influences and Processes.- IX. Ecological Developments in Leguminous Fruits.- X. Dispersal and the Evolution of Grasses.- A. Comparison with Cyperaceae.- B. Return to Gramineae (i.c. Oryzeae).- C. Bambusoid Grasses.- D. Bamboos.- E. Open Plains and Higher Grasses.- F. Some More Remarks on Awns and on Establishment.- G. Retrospective Views.- XI. Man and His Plants in Relation to Dispersal.- References.- Index of Scientific Plant Names.- Index of Scientific Animal Names.
1,679 citations
TL;DR: It is argued that genetic methods provide a broadly applicable way to monitor long-distance seed dispersal and, hence, that better data is needed from the tails of seeds that travel long distances.
Abstract: Long-distance seed dispersal influences many key aspects of the biology of plants, including spread of invasive species, metapopulation dynamics, and diversity and dynamics in plant communities. However, because long-distance seed dispersal is inherently hard to measure, there are few data sets that characterize the tails of seed dispersal curves. This paper is structured around two lines of argument. First, we argue that long-distance seed dispersal is of critical importance and, hence, that we must collect better data from the tails of seed dispersal curves. To make the case for the importance of long-distance seed dispersal, we review existing data and models of long-distance seed dispersal, focusing on situations in which seeds that travel long distances have a critical impact (colonization of islands, Holocene migrations, response to global change, metapopulation biology). Second, we argue that genetic methods provide a broadly applicable way to monitor long-distance seed dispersal; to place this argument in context, we review genetic estimates of plant migration rates. At present, several promising genetic approaches for estimating long-distance seed dispersal are under active development, including assignment methods, likelihood methods, genealogical methods, and genealogical/demographic methods. We close the paper by discussing important but as yet largely unexplored areas for future research.
1,121 citations
"Seed Dispersal Distances by Ants In..." refers background in this paper
...This issue can affect population growth and persistence, unless other forms of infrequent long dispersal events occur (Cain et al., 2000; Nathan et al., 2008)....
[...]