Field-level bird abundances are enhanced by landscape-scale agri-environment scheme uptake

Despite two decades of agri-environment schemes (AESs) aimed at mitigating farmland biodiversity losses, the evidence that such programmes actually benefit biodiversity remains limited. Using field-level surveys, we assess the effectiveness of AESs in enhancing bird abundances in an upland area of England, where schemes have been operating for over 20 years. In such a region, the effects of AESs should be readily apparent, and we predict that bird abundances will co-vary with both field- and landscape-scale measures of implementation. Using an information theoretic approach, we found that, for abundances of species of conservation concern and upland specialists, measures of AES implementation and habitat type at both scales appear in the most parsimonious models. Field-level bird abundances are higher where more of the surrounding landscape is included in an AES. While habitat remains a more influential predictor, we suggest that landscape-scale implementation results in enhanced bird abundances. Hence, measures of the success of AESs should consider landscape-wide benefits as well as localized impacts.

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Habitat selection by nesting and brood-rearing sharp-tailed grouse

Canadian Journal of Zoology ◽

10.1139/z09-016 ◽

2009 ◽

Vol 87 (4) ◽

pp. 326-336 ◽

Cited By ~ 6

Author(s):

Alicia D. Goddard ◽

Russell D. Dawson ◽

Michael P. Gillingham

Keyword(s):

Spatial Scales ◽

Conditional Logistic Regression ◽

Habitat Type ◽

Theoretic Approach ◽

Information Theoretic ◽

Logistic Regression Models ◽

Brood Rearing ◽

Shrub Steppe ◽

Information Theoretic Approach ◽

Selection Of

Breeding success is a critical component of population stability and is often influenced by the habitats used during the breeding season. Current hypotheses suggest that sharp-tailed grouse ( Tympanuchus phasianellus (L., 1758)) select nest and brood-rearing habitats that provide both lateral and overhead cover to avoid detection by predators. We examined the selection of nesting and brood-rearing habitats of sharp-tailed grouse at three spatial scales (landscape, patch, and site) in northeastern British Columbia using standard and conditional logistic regression models and an information–theoretic approach. At the patch and site scales, our results validate our predictions, as nesting females selected shrub–steppe habitats, greater shrub and grass cover, taller vegetation, and greater residual vegetation compared with random sites. Brood-rearing females selected for agricultural habitats during the early brood-rearing period (0–14 days), but did not show selection of any habitat type or site attribute during the late brood-rearing period (15–49 days). We suggest that the selection of shrub-dominated habitats by nesting females supports the hypothesis that females select sites and habitats that maximize concealment. We further suggest that selection of shrub-dominated habitat is occurring in response to changes in habitat conditions and availability, as natural grassland communities have diminished across the landscape.

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Are there habitat thresholds in koala occupancy in the semiarid landscapes of the Mulgalands Bioregion?

Wildlife Research ◽

10.1071/wr13010 ◽

2013 ◽

Vol 40 (5) ◽

pp. 413 ◽

Cited By ~ 4

Author(s):

Andrew G. Smith ◽

Clive McAlpine ◽

Jonathan Rhodes ◽

Leonie Seabrook ◽

Daniel Lunney ◽

...

Keyword(s):

Linear Relationship ◽

Landscape Scale ◽

Theoretic Approach ◽

Habitat Amount ◽

Information Theoretic ◽

Conservation Actions ◽

Scale Variable ◽

Landscape Scales ◽

Information Theoretic Approach ◽

A Site

Context Habitat thresholds are the critical point(s), below which the probability of occurrence of a species declines. Identifying thresholds assists land managers to decide how much habitat is needed to conserve a species. However, for any given species, a threshold may not exist, or might occur at one scale but not at others, and it may differ across regions. The use of critical habitat thresholds can negatively affect populations if simplified conservation targets for habitat retention are prescribed. This problem is relevant to the koalas where there is evidence of habitat thresholds in mesic regions, but no studies of thresholds in semiarid regions. Aims The aim of the present study was to investigate whether a threshold exists between the occupancy of a site by koalas and habitat variables at both the site and at four landscape scales in the semiarid Mulgalands Bioregion of Queensland, Australia. Methods We modelled habitat relationships using standard and piece-wise logistic regression, and an information-theoretic approach, to determine whether the best model that explained the occupancy–habitat relationships was linear or had a distinct threshold. The site-scale variable was the percentage of primary eucalypt species. The landscape-scale variables included the amount of primary and secondary habitat, and an interaction between them. Key findings There was a threshold relationship between the occurrence of koalas and the percentage of primary trees at the site scale. At the landscape scale, most threshold models failed to converge, and evidence pointed to a linear relationship between habitat amount and koala occupancy. Conclusions Conservation actions for koalas in the Mulgalands Bioregion should concentrate on protecting the primary tree resource for koalas, namely, river red gums (E. camaldulensis). However, the maintenance or restoration of primary and secondary habitat to distances of 1000 m from the creek is important because of the linear relationship between koala presence and habitat amount. Implications As habitat is lost in the semiarid Mulgalands Bioregion, koala occupancy declines. If known thresholds from mesic regions are used to define a minimum amount of habitat to be retained for koalas, conservation of local koala populations may well fail.

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