Relationships between hunting management and conservation of biodiversity

Miguel Delibes-Mateos & Beatriz Arroyo

Key message

Research on the impact of hunting on biodiversity has shown that hunting (and its associated management) can be a strong driver in conserving biodiversity, because many of the objectives in hunting (maintaining healthy populations, preserving natural habitats, reducing limiting factors for game) are shared with those of wildlife management and conservation at large.

However, sometimes hunting has negative consequences on biodiversity, usually because of certain management activities performed in unsustainable ways, and these are maintained because of economic or cultural reasons.

Additionally, hunting may benefit certain species, but not others, and the overall benefit of hunting for biodiversity and conservation will depend on the relative value that is attached to different animal guilds or species in different contexts.

Overall, our research indicates that hunting estates that have benefits for biodiversity should be identified and favoured over those that are not.

 

Messages from the case studies

 

Scottish highlands

Our research showed that overall bird species richness or diversity was not strongly influenced by upland management (in estates dedicated to game bird shooting, deer stalking, sheep production, or conservation), but bird community structure was significantly affected by predator control and prescribed burning. Bird communities were simpler in those estates that had predator control, or XXX.

 

Management for gamebirds in Iberian farmland estates

Estates dedicated to small game (mainly red-legged partridges) in the Iberian Peninsula are mainly farmland areas with varying degree of natural vegetation areas (mainly Mediterranean scrubland or pastures) mixed within the agricultural matrix.

Management carried out to benefit partridges includes provision of supplementary food (grain) and water, predator control, the provision of game crops, or (increasingly in recent decades) the release of farm-reared partridges. Our studies have shown that, in central Spain the commercialization of hunts is associated to more intensive management and to estates with a higher proportion of natural vegetation (the latter of which is thought to be associated to higher nature value in farmland areas).

In Portugal, areas managed for hunting contained higher densities of birds of conservation concern, higher densities of steppe birds and other ground-nesting species than areas not managed for hunting of similar habitats. They also contained higher densities of partridges and rabbits, which in turn was reflected in higher raptor densities, although raptor abundance was proportionally lower than expected by game and habitat in those estates with higher gamekeeper densities, which suggested that illegal control could be existing (Beja et al. 2009).

Within central Spain, more detailed analyses on management activities and their effect on bird guilds showed that supplementary food benefited granivorous steppe birds like sandgrouse, and fox control benefitted non-granivourous steppe birds like little bustards.

Management (in particular, habitat and supplementary food) were reflected in higher partridge densities, which in turn were associated to higher raptor richness (but not densities). In contrast, small-scale partridge releases seemed to be inefficient to increase partridge abundance or bags, but large-scale partridge releases (such as those carried out in intensive estates), although having a direct positive impact on harvest and thus estate economies, were negatively associated to steppe bird abundance or raptor diversity, suggesting lower biodiversity value of that type of management.

Broadly, our results suggest that, in Iberian farmland, game management activities directed to benefit wild red-legged partridges and other associated small game (in particular, habitat management, predator control or food enhancement) have positive effects on other farmland birds of conservation concern, but that these benefits disappear when management is intensive and based on large-scale releases of farm-reared partridges.

However, the latter is much more profitable economically. Thus, there is a need to maintain economic sustainability of wild red-legged partridges estates managed in a sustainable way, and thus contributing to overall conservation of farmland wildlife.

 

Papers to be submitted in next 2 months (manuscripts in final or near-final draft)

Estrada, A., Delibes-Mateos, M., Caro, J., Diaz-Fernandez, S., Casas, F., Viñuela, J. & Arroyo, B. Hunting management for red-legged partridges benefits steppe birds. J. Appl. Ecology

Abstract:

In Europe, sport hunting and its associated management has been performed for centuries and has had profound effects on our landscapes and on the biodiversity they hold. Nowadays, hunting management has become an important and potential tool to guaranty game and wildlife conservation, specifically red-legged partridge hunting is a relevant socio-economic activity in Western Europe. We investigated the relationship between red-legged partridge hunting management, raptor and steppe-bird diversity in Central Spain. We surveyed 54 red-legged partridge hunting estates with varying game management intensity in spring and/or summer 2006-2010. Birds were counted from fixed points. Information about game management was gathered through interviews with game managers. We modelled the abundance and number of species of each bird group in each estate according to habitat variables and game management variables (mainly artificial feeding, releases of farm-reared birds and predator control) with GLMMs and selected the models with lowest AICc. Our results show that raptor abundance is associated to habitat, not management. Partridge abundance had a positive relationship with the number of raptor species observed but not with their abundance. On the contrary, management tools employed for partridge populations improvement, seems to have positive effect on steppe birds, which share habitat requirements with them. We conclude that management implemented for red-legged partridges in Central Spain does not seem to have neither positive nor negative effects on the abundance of their predators (raptors), but higher partridge’s densities have a positive effect on raptor diversity. However, some activities leading to improve red-legged partridges have a positive effect on co-existing species (steppe-birds). All models are affected by habitat variables, so it is very important to maintain the habitat that allows those high densities and that has a positive effect on biodiversity.

Caro, J., Delibes-Mateos, M., Estrada, A. Beja, P., Borralho, R., Gordinho, L., Reino, L. & Arroyo, B. Positive effects of hunting management on farmland birds: an empirical study in Portugal. Biol. Cons.

Abstract:
Recreational hunting has been cited as a potential problem for biodiversity. This activity is currently under discussion at both international and regional levels, requiring better understanding of responses of non-game species to game management. We investigated how game managements affect the diversity and abundance of four groups (guilds) of farmland birds (Passerines, Steppe birds, Ground-nesting birds and Endangered bird species) in 24 game estates of Southern Portugal. Our results showed that steppe birds, ground-nesting birds and birds of conservation concern were more abundant and diverse in areas managed for red-legged partridges (Alectoris rufa) and other associated small game species than in areas of similar habitat but where no management occurs, suggesting that these bird guilds benefit of game management. Passerine richness and abundance appeared to depend mostly on habitats with higher vegetation structural heterogeneity rather than on management. Our results thus demonstrate that hunting management is an important factor affecting several species in farmland habitats in southern Iberian Peninsula. Therefore, joint work between hunting managers and conservation actors could be highly beneficial for the conservation of farmland bird species, some of which have suffered strong declines populations within their ranges.

Diaz-Fernandez, S., Casas, F. Caro, J. Haro, M., Viñuela, J., & Arroyo, B.. Effect of management techniques on red-legged partridge abundance. J. Appl. Ecology

Abstract:
1. The increasing investment on management practices in gamebird estates, the controversy around the usefulness of these practices or their effects on non-target species, and the socio-economic impact around gamebird hunting, makes the study of the impact of game management on wild gamebird populations particularly interesting to improve hunting management and biodiversity conservation.

2. Red-legged partridge (Alectoris rufa) is the most important gamebird in Spain, and management to improve their populations is applied throughout the territory. This management includes mainly provision of supplementary food and water, predator control and recently increasingly releases of farm-bred partridges. However, no comprehensive study of the effect of these practices on partridge densities has ever been developed.

3. We used questionnaires and field bird surveys in 48 hunting estates to assess whether summer red-legged partridge abundance was related to the intensity of management tools, to harvest intensity or to habitat.

4. Post-breeding red-legged partridge abundance was higher in estates with mixed farmland and Mediterranean scrub. Additionally, it was positively related to the density of supplementary food and water points, but negatively to the number of partridges released. Harvest intensity was negatively related to partridge abundance, although including this variable did not significantly improve the model. Predator control intensity was not included in any of the selected models as an explanatory variable of partridge abundance in our study area. The best model included both habitat and management variables, although management variables were more important than habitat in explaining variability in abundance.

5. As food and water supplementation explained better than habitat partridge abundance, we may suspect possible problems of food availability in the surrounding habitat, whose improvement should be compared in economic terms with that of provision of supplementary food. The negative relationship of releases with summer abundances clearly indicates that they are not contributing to increase wild partridge abundance in hunting estates. Predator control, one of the most time-consuming and widespread practices applied in hunting estates, apparently is not useful to increase partridge summer abundances, at least as currently implemented.

Synthesis and applications. Management seemed to have a stronger effect than habitat in explaining post-breeding abundances, which suggests that its application is beneficial. However, this effect varied among management tools, as some had the desired effect (an increase in partridge abundance), whereas others were not and can be thus considered inefficient, so their use should be reconsidered from both ecological and economical points of view.

Mustin, K., Arroyo, B., Beja, P., Bro, E., Newey, S. Knott, J. Redpath, S & Irvine, J. Two birds with one stone: can biodiversity conservation and game bird management be reconciled? J. Appl. Ecol.

Newey, S., Mustin, K., Bryce, R., Fielding, D., Bronwen, D. & Irvine, J. Bird diversity and game management in the Scottish Highlands, UK. J. Appl. Ecol.

Submitted

Diaz-Fernandez, S., Diaz-Fernandez, M., Arroyo, B. & Viñuela, J. Economic consequences of red-legged partridge restocking in Spanish private hunting estates. Environmental Management.

Delibes-Mateos, M., Díaz-Fernández, S., Ferreras, P., Viñuela, J & Arroyo, B. The role of economic and social factors driving predator control in small game estates in central Spain. Ecology and Society.

Abstract:
One of the most important human-wildlife conflicts in the world is that where predators are involved. Predator species may compete with us for the same resources, such as game species. As a consequence, predators have been frequently controlled by game managers, which has negatively affected many predator populations worldwide. The understanding of human-wildlife conflicts requires a multidisplicinary framework that is rarely considered. In this study, we aim to evaluate the attitudes and behaviour of game managers with regard to predator management in central Spain, as well as to explore factors that lead to these attitudes and behaviour. Data were gathered through face to face interviews with game managers from 59 small-game hunting estates within central Spain. Predator control was employed in 90 % of the estates, but control intensity was very variable among estates. The main methods employed were cage-traps and shooting, but some illegal practices (e.g. leg-hold traps or snares without stopping devices) were also admittedly used for carnivores. Most managers considered that efficacy of legal methods for control of foxes was very limited. Overall, non-selective methods, such as some types of snares, were more frequently employed in commercial than in non-commercial estates. Most managers believed that predators had an important effect on prey, and therefore that not doing it would lead to smaller hunting bags. Only managers from commercial hunting estates used stronger discourses such as that hunting would be impossible without carrying out predator control, which suggests that their tolerance for predators was lower than that of managers whose main motivation was not economic. Most managers considered that predator control was effective to reduce the number of predators, but only in the short term. Therefore, they highlighted the need of maintaining predator control every year. Our results highlight the important role that both social and economic factors (even stronger roles than ecological factors) play driving predator control, and therefore the need of incorporating these factors when making decisions to mitigate the human-predator conflict.



Diaz-Fernandez, S., Arroyo, B. Viñuela, J., Patiño, I. & Riera, P. Market value of restocking and landscape management in red-legged partridge hunting. J. Wildlife Management.

Abstract:

Management of red-legged partridge hunting in Spanish commercial estates increasingly integrates annual restocking of farm-reared partridges, whose economic yield is not clear. Worrying medium-term effects on wild partridge populations have been proved, whereas efficacy of releases to improve harvest is restricted to massive restocking. To study economic consequences of restocking at the level of management decision, the hunting estate, we gathered information on management in 59 partridge estates through face-to-face interviews with hunting managers. We defined the main generic expenses and revenues of red-legged partridge hunting, and took stock of 9 commercial estates with different release intensity. We found greater revenues, profitability and expenses in intensive estates (massive releases) than in others, but also lesser expenses per partridge hunted. Their great production, much over the limits of wild populations, was a key for their competitiveness. The real options of deferring investments and expanding the offer that restocking gives to hunting estates are another advantage of releases, and may be a possible explanation of the widespread motivation to restock in hunting estates, although in non-intensive estates the inefficacy of restocking to increase partridge availability compensates the possible financial advantages from real options. We found 4 cases where commercial partridge hunting was not profitable (occurring in estates where hunting is a complementary activity), and 3 of them released annually farmreared partridges. Red-legged partridge hunting in our study estates without releases was profitable, but not competitive with intensive estates within the same market and prices. There is margin to optimize management costs in estates that manage only wild partridges. Moreover, if releases had a social cost (which should be evaluated) and we wanted to reduce it, mechanisms as internalization of costs, such as market or fiscal differentiation through quality or eco-labels, would be necessary to encourage managers to implement sustainable wild red-legged partridge hunting.

 

Published

Diaz-Fernandez, S., Viñuela, J. & Arroyo, B. 2012. Harvest of Red-legged partridge in central Spain. J. Wild. Manag. (DOI: 10.1002/jwmg.391)

Abstract:
A basic rule to attain sustainable use of harvested resources is to adjust take to availability. Populations of red-legged partridges in Spain have decreased in recent decades, and releases of farm-bred partridges to improve short-term availability are increasingly common. We used questionnaires and bird surveys to assess whether harvest was related to availability of wild partridges or intensity of farm-bred partridge releases. We studied 50 hunting estates, including 6 administratively labeled as intensive (with few numerical and temporal restrictions to releases). In addition, we considered hunting pressure (number of hunters _ hunting days/km2) and habitat as explanatory variables in the analyses. In intensive estates, annual harvest was exclusively related to release intensity, indicating that in these estates hunting is detached from natural resources and approaches an industrial activity based on external inputs. In non-intensive estates, harvest was affected by wild stock availability, walked-up shooting pressure, and habitat (greater harvest in estates with more Mediterranean shrubland). In these estates, releases did not increase annual harvest, and can be considered an inefficient practice. Additionally, the relationship between abundance estimates and harvest disappeared in estates with low partridge abundance estimates, suggesting possibilities for overharvesting in a large proportion of estates. Increasing the abundance of wild red-legged partridge through techniques like habitat management, and improving the adjustment of harvest to availability, may be a good strategy to increase long-term harvest in non-intensive estates. Additionally, Government and managers must create ways to segregate and label the estates where only wild red-legged partridges are managed from those where releases are used, to reduce ecological costs of management decisions.

 

Arroyo, B., Delibes-Mateos, M., Diaz-Fernandez, S., & Viñuela, J. 2012. Hunting management in relation to economic aims: red-legged partridge hunting in central Spain. E J Wildl Res. (DOI 10.1007/s10344-012-0632-4)

Abstract:
Game management is widely implemented in Spain, affecting more than 70 % of land cover. Management intensity may be linked to the financial aims of hunting estates, but no study of these aspects has been developed in Spain, where commercial hunting is common. Through interviews with game managers and field surveys, we quantified physical and economic traits, management techniques, and hunting methods in a sample of 59 small-game hunting estates located in south-central Spain (where red-legged partridge hunting has the highest socioeconomic importance in the country). We compared non-commercial estates (aimed for leisure, managed mainly by local hunting societies) and commercial estates (aimed at financial benefit); among the latter, we also assessed “intensive” estates (a special category of commercial estates licensed to release farm-reared partridges without temporal or numerical limits throughout the hunting season). Commercial estates had more intensive management, including more and larger partridge releases, higher density of supplementary feeders and more intensive predator control. Thus, any positive or negative effects on biodiversity of these management techniques would be higher in commercial than in noncommercial estates. Commercial estates also retained more natural vegetation, which may help to enhance the landscape and biodiversity value of farmland in central Spain. On the other hand, differences in management and hunting styles were most marked between intensive and other type of estates (both commercial and non-commercial); this indicates that intensive estates are qualitatively different from other small-game estates, both ecologically (hunting based on releases and driven shooting) and economically (higher inputs and outputs). It would be desirable to find ways to quantify the environmental or social costs and benefits of different management techniques, and integrate them in the economics of hunting estates.

 

Reports and MSc theses available online:

• Bronwen Daniel (2010) Effects of sporting estate management practices on biodiversity in Scotland (with Dr R. Bryce & Prof S. Redpath, University of Aberdeen)
• Mustin, K., Newey, S., Irvine, J., Arroyo, B. & Redpath, S. Biodiversity impacts of game bird hunting and associated management practices in Europe and North America. (2011) Report to RSPB

 

 

Additional papers in the pipeline:
We will be working this summer on a paper on the influence of game crops on distribution and productivity of red-legged partridges (with L. Reino, and R. Borralho in Portugal).

We will also be working this summer on a paper on the Spanish partridge case study, with N. Bunnefeld and EJ Milner-Gulland.