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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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Study Design.a) The distribution of temperate grassland and grassy woodlands (grey) across Australia. Selected study regions are shown (black outline) and expanded in b) location of study sites within south-eastern NSW and central Victoria, with protected areas shown in grey, sites shown as black dots and major towns as large black diamonds, c) an example of stratified random placement of study plots within a study site showing open woodland (light grey), woodland (grey) and open forest (dark grey) canopy types, and d) the layout of tiles (box) and circular survey disks (circle) within the study plot.
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pone-0105966-g001: Study Design.a) The distribution of temperate grassland and grassy woodlands (grey) across Australia. Selected study regions are shown (black outline) and expanded in b) location of study sites within south-eastern NSW and central Victoria, with protected areas shown in grey, sites shown as black dots and major towns as large black diamonds, c) an example of stratified random placement of study plots within a study site showing open woodland (light grey), woodland (grey) and open forest (dark grey) canopy types, and d) the layout of tiles (box) and circular survey disks (circle) within the study plot.

Mentions: Our study was conducted within the range of temperate grassland and grassy Eucalyptus woodland communities across south-eastern Australia (Fig. 1a). These threatened communities have been extensively cleared and modified over the past 200 years [47]. Remnant vegetation persists mostly as fragmented, often small (<1,000 ha) patches embedded in an agricultural matrix [47].


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)

Study Design.a) The distribution of temperate grassland and grassy woodlands (grey) across Australia. Selected study regions are shown (black outline) and expanded in b) location of study sites within south-eastern NSW and central Victoria, with protected areas shown in grey, sites shown as black dots and major towns as large black diamonds, c) an example of stratified random placement of study plots within a study site showing open woodland (light grey), woodland (grey) and open forest (dark grey) canopy types, and d) the layout of tiles (box) and circular survey disks (circle) within the study plot.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0105966-g001: Study Design.a) The distribution of temperate grassland and grassy woodlands (grey) across Australia. Selected study regions are shown (black outline) and expanded in b) location of study sites within south-eastern NSW and central Victoria, with protected areas shown in grey, sites shown as black dots and major towns as large black diamonds, c) an example of stratified random placement of study plots within a study site showing open woodland (light grey), woodland (grey) and open forest (dark grey) canopy types, and d) the layout of tiles (box) and circular survey disks (circle) within the study plot.
Mentions: Our study was conducted within the range of temperate grassland and grassy Eucalyptus woodland communities across south-eastern Australia (Fig. 1a). These threatened communities have been extensively cleared and modified over the past 200 years [47]. Remnant vegetation persists mostly as fragmented, often small (<1,000 ha) patches embedded in an agricultural matrix [47].

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