Limits...
Eaten out of house and home: impacts of grazing on ground-dwelling reptiles in Australian grasslands and grassy woodlands.

Howland B, Stojanovic D, Gordon IJ, Manning AD, Fletcher D, Lindenmayer DB - PLoS ONE (2014)

Bottom Line: Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers.Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles.Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity.

View Article: PubMed Central - PubMed

Affiliation: Fenner School of Environment and Society, ANU College of Medicine, Biology & Environment Frank Fenner Building, # 141 Australian National University, Canberra, ACT, 0200, Australia.

ABSTRACT
Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1) density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2) grass structure and reptiles (i.e. abundance, richness, diversity and occurrence) across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities. Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity. Our data indicate that to maximize reptile abundance, species richness, species diversity, and occurrence of several individual species of reptile, managers will need to subject different areas of the landscape to moderate and low grazing intensities and limit the occurrence and extent of high grazing.

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Related in: MedlinePlus

Graphical representation of logistic regression models summarized in Table 2.The graphs show significant relationships between PC1 values (grass structure) and the probability of encountering a species in a given plot for the a) eastern three-toe earless skink, and b) legless lizard. Fitted relationships are shown as a solid line, with actual values shown as an open circle. Standard error of the model predictions are shown as a dotted line. To aid interpretation of results, variables have been back-transformed to original scale.
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pone-0105966-g006: Graphical representation of logistic regression models summarized in Table 2.The graphs show significant relationships between PC1 values (grass structure) and the probability of encountering a species in a given plot for the a) eastern three-toe earless skink, and b) legless lizard. Fitted relationships are shown as a solid line, with actual values shown as an open circle. Standard error of the model predictions are shown as a dotted line. To aid interpretation of results, variables have been back-transformed to original scale.

Mentions: The graphs show significant relationship between grass structure (PC1) for a) reptile abundance, b) reptile species richness and c) reptile species diversity in a given plot. Fitted relationships are shown as a solid line, with actual values shown as an open circle. Standard error of the model predictions are shown as a dotted line. To aid interpretation of results, variables have been back-transformed to original scale.


Eaten out of house and home: impacts of grazing on ground-dwelling reptiles in Australian grasslands and grassy woodlands.

Howland B, Stojanovic D, Gordon IJ, Manning AD, Fletcher D, Lindenmayer DB - PLoS ONE (2014)

Graphical representation of logistic regression models summarized in Table 2.The graphs show significant relationships between PC1 values (grass structure) and the probability of encountering a species in a given plot for the a) eastern three-toe earless skink, and b) legless lizard. Fitted relationships are shown as a solid line, with actual values shown as an open circle. Standard error of the model predictions are shown as a dotted line. To aid interpretation of results, variables have been back-transformed to original scale.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263405&req=5

pone-0105966-g006: Graphical representation of logistic regression models summarized in Table 2.The graphs show significant relationships between PC1 values (grass structure) and the probability of encountering a species in a given plot for the a) eastern three-toe earless skink, and b) legless lizard. Fitted relationships are shown as a solid line, with actual values shown as an open circle. Standard error of the model predictions are shown as a dotted line. To aid interpretation of results, variables have been back-transformed to original scale.
Mentions: The graphs show significant relationship between grass structure (PC1) for a) reptile abundance, b) reptile species richness and c) reptile species diversity in a given plot. Fitted relationships are shown as a solid line, with actual values shown as an open circle. Standard error of the model predictions are shown as a dotted line. To aid interpretation of results, variables have been back-transformed to original scale.

Bottom Line: Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers.Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles.Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity.

View Article: PubMed Central - PubMed

Affiliation: Fenner School of Environment and Society, ANU College of Medicine, Biology & Environment Frank Fenner Building, # 141 Australian National University, Canberra, ACT, 0200, Australia.

ABSTRACT
Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1) density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2) grass structure and reptiles (i.e. abundance, richness, diversity and occurrence) across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities. Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity. Our data indicate that to maximize reptile abundance, species richness, species diversity, and occurrence of several individual species of reptile, managers will need to subject different areas of the landscape to moderate and low grazing intensities and limit the occurrence and extent of high grazing.

Show MeSH
Related in: MedlinePlus