Click
here to close Hello! We notice that
you are using Internet Explorer, which is not supported by Echinobase
and may cause the site to display incorrectly. We suggest using a
current version of Chrome,
FireFox,
or Safari.
Sublethal effects of a rapidly spreading native alga on a key herbivore.
Bradley DJ
,
Boada J
,
Gladstone W
,
Glasby TM
,
Gribben PE
.
???displayArticle.abstract???
Multiple anthropogenic stressors are causing a global decline in foundation species, including macrophytes, often resulting in the expansion of functionally different, more stressor-tolerant macrophytes. Previously subdominant species may experience further positive demographic feedback if they are exposed to weaker plant-herbivore interactions, possibly via decreased palatability or being structurally different from the species they are replacing. However, the consequences of the spread of opportunistic macrophytes for the local distribution and life history of herbivores are unknown.The green alga, Caulerpa filiformis, previously a subdominant macrophyte on low intertidal-shallow subtidal rock shores, is becoming locally more abundant and has spread into warmer waters across the coast of New South Wales, Australia.In this study, we measured (a) the distribution and abundance of a key consumer, the sea urchin Heliocidaris erythrogramma, across a seascape at sites where C. filiformis has become dominant, (b) performed behavioral field experiments to test the role of habitat selection in determining the local distribution of H. erythrogramma, and (c) consumer experiments to test differential palatability between previously dominant higher quality species like Ecklonia radiata and Sargassum sp. and C. filiformis and the physiological consequences of consuming it.At all sites, urchin densities were positively correlated with distance away from C. filiformis beds, and they actively moved away from beds. Feeding experiments showed that, while urchins consumed C. filiformis, sometimes in equal amounts to higher quality algae, there were strong sublethal consequences associated with C. filiformis consumption, mainly on reproductive potential (gonad size). Specifically, the gonad size of urchins that fed on C. filiformis was equivalent to that in starved urchins. There was also a tendency for urchin mortality to be greater when fed C. filiformis.Overall, strong negative effects on herbivore life-history traits and potentially their survivorship may establish further positive feedback on C. filiformis abundance that contributes to its spread and may mediate shifts from top-down to bottom-up control at locations where C. filiformis has become dominant.
FIGURE 1. Map of study locations (i.e., Mona Vale, Bulli, and Wollongong) on the east coast of Australia (a), New South Wales. The top right photograph shows a shallow rocky landscape dominated by turfing algae with the presence of Sargassum spp and Eklonia radiata (b) while the bottom right photograph (c) shows Mona Vale, dominated by C. filiformis
FIGURE 2. (a) Density of urchin H. erythrogramma in the studied region inside, at the edge and outside C. filiformis patches. (b) Density of homing scars inside, at the edge and outside C. filiformis patches. (c) Percentage of homing scars occupied by an individual of H. erythrogramma. Data in plots represent the values for all 3 locations
FIGURE 3. Number of urchins found at each position at the end of experiment of those place (a) inside C. filiformis, (b) at the edge between the two habitats, and (c) outside C. filiformis patches at the beginning of the experiment
FIGURE 4. Urchin consumption (grams consumed) of each of C. filiformis, E. radiata and Sargassum spp in no‐choice food assays. Dark lines in boxplot represent the median values found per treatment
FIGURE 5. Two‐choice experiment results when urchins were offered (a) E. radiata & Sargassum spp, (b) C. filiformis & Sargassum spp, and (c) C. filiformis & E. radiata in total grams consumed. The black line in boxplots represents the median values. The top x‐axis represents the Wilcoxon test results on the preferences between the two‐choice items
FIGURE 6. Lethal and nonlethal effects of feeding on C. filiformis compared with E. radiata or starved. (a) Sea urchin mortality at the end of the experiment, (b) calcareous body proportion weight in grams, (c) gonad weight in grams, and (d) the ratio of gonad to calcareous body weight
Bach,
Host plant growth form and diversity: Effects on abundance and feeding preference of a specialist herbivore, Acalymma vittata (Coleoptera: Chrysomelidae).
1981, Pubmed
Bach,
Host plant growth form and diversity: Effects on abundance and feeding preference of a specialist herbivore, Acalymma vittata (Coleoptera: Chrysomelidae).
1981,
Pubmed
Boada,
Immanent conditions determine imminent collapses: nutrient regimes define the resilience of macroalgal communities.
2017,
Pubmed
,
Echinobase
Bradley,
Relationships between the spread of Caulerpa filiformis and fish communities on temperate rocky reefs.
2018,
Pubmed
Bulleri,
The seaweed Caulerpa racemosa on Mediterranean rocky reefs: from passenger to driver of ecological change.
2010,
Pubmed
Didham,
Are invasive species the drivers of ecological change?
2005,
Pubmed
Felline,
Subtle effects of biological invasions: cellular and physiological responses of fish eating the exotic pest Caulerpa racemosa.
2012,
Pubmed
Gribben,
Habitat provided by native species facilitates higher abundances of an invader in its introduced compared to native range.
2020,
Pubmed
Gribben,
Sublethal effects on reproduction in native fauna: are females more vulnerable to biological invasion?
2006,
Pubmed
Kriegisch,
Drift-kelp suppresses foraging movement of overgrazing sea urchins.
2019,
Pubmed
,
Echinobase
Krumhansl,
Global patterns of kelp forest change over the past half-century.
2016,
Pubmed
Lanham,
Beyond the border: effects of an expanding algal habitat on the fauna of neighbouring habitats.
2015,
Pubmed
Ling,
Density-dependent feedbacks, hysteresis, and demography of overgrazing sea urchins.
2019,
Pubmed
,
Echinobase
McArthur,
The dilemma of foraging herbivores: dealing with food and fear.
2014,
Pubmed
Miranda,
Invasion-mediated effects on marine trophic interactions in a changing climate: positive feedbacks favour kelp persistence.
2019,
Pubmed
Noè,
Food selection of a generalist herbivore exposed to native and alien seaweeds.
2018,
Pubmed
,
Echinobase
O'Brien,
Nipped in the bud: mesograzer feeding preference contributes to kelp decline.
2016,
Pubmed
Pagès,
The Mediterranean benthic herbivores show diverse responses to extreme storm disturbances.
2013,
Pubmed
,
Echinobase
Pessarrodona,
Consumptive and non-consumptive effects of predators vary with the ontogeny of their prey.
2019,
Pubmed
,
Echinobase
Russell,
Bioerosion by pit-forming, temperate-reef sea urchins: History, rates and broader implications.
2018,
Pubmed
,
Echinobase
Steneck,
Herbivory in the marine realm.
2017,
Pubmed
Underwood,
Effects of interactions between algae and grazing gastropods on the structure of a low-shore intertidal algal community.
1981,
Pubmed
Uyà,
Facilitation of an invader by a native habitat-former increases along interacting gradients of environmental stress.
2020,
Pubmed
Vergés,
Long-term empirical evidence of ocean warming leading to tropicalization of fish communities, increased herbivory, and loss of kelp.
2016,
Pubmed
Vergés,
The tropicalization of temperate marine ecosystems: climate-mediated changes in herbivory and community phase shifts.
2014,
Pubmed
Voerman,
Habitat associations of an expanding native alga.
2017,
Pubmed
Voerman,
Morphological variation of a rapidly spreading native macroalga across a range of spatial scales and its tolerance to sedimentation.
2019,
Pubmed
Wernberg,
Climate-driven regime shift of a temperate marine ecosystem.
2016,
Pubmed
Weterings,
Food quality and quantity are more important in explaining foraging of an intermediate-sized mammalian herbivore than predation risk or competition.
2018,
Pubmed
Wright,
Disturbance-mediated facilitation by an intertidal ecosystem engineer.
2017,
Pubmed
Zhang,
Mechanisms influencing the spread of a native marine alga.
2014,
Pubmed
