Stress triangle: do introduced predators exert indirect costs on native predators and prey?
Non-consumptive effects of predators on each other and on prey populations often exceed the effects of direct predation. These effects can arise from fear responses elevating glucocorticoid (GC) hormone levels (predator stress hypothesis) or from increased vigilance that reduces foraging efficiency...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2013-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3621665?pdf=render |
| _version_ | 1818623766045917184 |
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| author | Jennifer R Anson Chris R Dickman Rudy Boonstra Tim S Jessop |
| author_facet | Jennifer R Anson Chris R Dickman Rudy Boonstra Tim S Jessop |
| author_sort | Jennifer R Anson |
| collection | DOAJ |
| description | Non-consumptive effects of predators on each other and on prey populations often exceed the effects of direct predation. These effects can arise from fear responses elevating glucocorticoid (GC) hormone levels (predator stress hypothesis) or from increased vigilance that reduces foraging efficiency and body condition (predator sensitive foraging hypothesis); both responses can lead to immunosuppression and increased parasite loads. Non-consumptive effects of invasive predators have been little studied, even though their direct impacts on local species are usually greater than those of their native counterparts. To address this issue, we explored the non-consumptive effects of the invasive red fox Vulpes vulpes on two native species in eastern Australia: a reptilian predator, the lace monitor Varanus varius and a marsupial, the ringtail possum Pseudocheirus peregrinus. In particular, we tested predictions derived from the above two hypotheses by comparing the basal glucocorticoid levels, foraging behaviour, body condition and haemoparasite loads of both native species in areas with and without fox suppression. Lace monitors showed no GC response or differences in haemoparasite loads but were more likely to trade safety for higher food rewards, and had higher body condition, in areas of fox suppression than in areas where foxes remained abundant. In contrast, ringtails showed no physiological or behavioural differences between fox-suppressed and control areas. Predator sensitive foraging is a non-consumptive cost for lace monitors in the presence of the fox and most likely represents a response to competition. The ringtail's lack of response to the fox potentially represents complete naiveté or strong and rapid selection to the invasive predator. We suggest evolutionary responses are often overlooked in interactions between native and introduced species, but must be incorporated if we are to understand the suite of forces that shape community assembly and function in the wake of biological invasions. |
| first_indexed | 2024-12-16T18:46:16Z |
| format | Article |
| id | doaj.art-589a738f8b244f3a9e48456afb2daf93 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-16T18:46:16Z |
| publishDate | 2013-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-589a738f8b244f3a9e48456afb2daf932022-12-21T22:20:51ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0184e6091610.1371/journal.pone.0060916Stress triangle: do introduced predators exert indirect costs on native predators and prey?Jennifer R AnsonChris R DickmanRudy BoonstraTim S JessopNon-consumptive effects of predators on each other and on prey populations often exceed the effects of direct predation. These effects can arise from fear responses elevating glucocorticoid (GC) hormone levels (predator stress hypothesis) or from increased vigilance that reduces foraging efficiency and body condition (predator sensitive foraging hypothesis); both responses can lead to immunosuppression and increased parasite loads. Non-consumptive effects of invasive predators have been little studied, even though their direct impacts on local species are usually greater than those of their native counterparts. To address this issue, we explored the non-consumptive effects of the invasive red fox Vulpes vulpes on two native species in eastern Australia: a reptilian predator, the lace monitor Varanus varius and a marsupial, the ringtail possum Pseudocheirus peregrinus. In particular, we tested predictions derived from the above two hypotheses by comparing the basal glucocorticoid levels, foraging behaviour, body condition and haemoparasite loads of both native species in areas with and without fox suppression. Lace monitors showed no GC response or differences in haemoparasite loads but were more likely to trade safety for higher food rewards, and had higher body condition, in areas of fox suppression than in areas where foxes remained abundant. In contrast, ringtails showed no physiological or behavioural differences between fox-suppressed and control areas. Predator sensitive foraging is a non-consumptive cost for lace monitors in the presence of the fox and most likely represents a response to competition. The ringtail's lack of response to the fox potentially represents complete naiveté or strong and rapid selection to the invasive predator. We suggest evolutionary responses are often overlooked in interactions between native and introduced species, but must be incorporated if we are to understand the suite of forces that shape community assembly and function in the wake of biological invasions.http://europepmc.org/articles/PMC3621665?pdf=render |
| spellingShingle | Jennifer R Anson Chris R Dickman Rudy Boonstra Tim S Jessop Stress triangle: do introduced predators exert indirect costs on native predators and prey? PLoS ONE |
| title | Stress triangle: do introduced predators exert indirect costs on native predators and prey? |
| title_full | Stress triangle: do introduced predators exert indirect costs on native predators and prey? |
| title_fullStr | Stress triangle: do introduced predators exert indirect costs on native predators and prey? |
| title_full_unstemmed | Stress triangle: do introduced predators exert indirect costs on native predators and prey? |
| title_short | Stress triangle: do introduced predators exert indirect costs on native predators and prey? |
| title_sort | stress triangle do introduced predators exert indirect costs on native predators and prey |
| url | http://europepmc.org/articles/PMC3621665?pdf=render |
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