Effect of Game Management on Wild Red-Legged Partridge Abundance

Nicola Saino,Silvia Díaz-Fernández,Fabián Casas,Javier Viñuela,Monica Martinez-Haro,Beatriz Arroyo

doi:10.1371/journal.pone.0066671

Nicola Saino, Silvia Díaz-Fernández + Show 4 more

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https://doi.org/10.1371/journal.pone.0066671

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Abstract

The reduction of game and fish populations has increased investment in management practices. Hunting and fishing managers use several tools to maximize harvest. Managers need to know the impact their management has on wild populations. This issue is especially important to improve management efficacy and biodiversity conservation. We used questionnaires and field bird surveys in 48 hunting estates to assess whether red-legged partridge Alectoris rufa young/adult ratio and summer abundance were related to the intensity of management (provision of supplementary food and water, predator control and releases of farm-bred partridges), harvest intensity or habitat in Central Spain. We hypothesized that partridge abundance would be higher where management practices were applied more intensively. Variation in young/adult ratio among estates was best explained by habitat, year and some management practices. Density of feeders and water points had a positive relationship with this ratio, while the density of partridges released and magpies controlled were negatively related to it. The variables with greatest relative importance were feeders, releases and year. Variations in post-breeding red-legged partridge abundance among estates were best explained by habitat, year, the same management variables that influenced young/adult ratio, and harvest intensity. Harvest intensity was negatively related to partridge abundance. The other management variables had the same type of relationship with abundance as with young/adult ratio, except magpie control. Variables with greatest relative importance were habitat, feeders, water points, releases and harvest intensity. Our study suggests that management had an overall important effect on post-breeding partridge abundance. However, this effect varied among tools, as some had the desired effect (increase in partridge abundance), whereas others did not or even had a negative relationship (such as release of farm-reared birds) and can be thus considered inefficient or even detrimental. We advise reconsidering their use from both ecological and economical points of view.

Highlights

The collapse of commercial fisheries and large-scale population declines of other harvested species are particular cases of the current biodiversity crisis that should be dealt within a conceptual framework integrating both ecological and social information [1], [2]
We studied the relationship between post-breeding partridge abundance and the intensity of various management tools currently applied in hunting estates, whilst taking into account two other variables that are known or expected to affect game densities
We hypothesized that partridge abundance would be higher where management practices were applied more intensively, but we were interested in knowing which contributed more to increase abundance, if applied simultaneously

Summary

Introduction

The collapse of commercial fisheries and large-scale population declines of other harvested species are particular cases of the current biodiversity crisis that should be dealt within a conceptual framework integrating both ecological and social information [1], [2]. Combining sound ecological knowledge of the harvested species, as well as a proper assessment of the effect of human actions to manage stocks, is essential to optimize long-term exploitation of the harvested resources [3]. Incorrect management programs may lead to resource depletion or extinction [4]. A critical management tool to maintain maximum sustainable harvest on wild game populations is to adaptively adjust harvest through the monitoring of game populations and the establishment of hunting quotas in relation to their abundance [7], [3]. [8]), mainly through a combination of environmental factors (such as agriculture intensification or climate change) and overexploitation or incorrect management [4] Many wild game populations have suffered severe declines in recent decades (e.g. [8]), mainly through a combination of environmental factors (such as agriculture intensification or climate change) and overexploitation or incorrect management [4]

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