Project
title / Integrating farm management practices with brown hare conservation in pastural habitats
/ DEFRA
project code / BD 1436

Department for Environment, Food and Rural Affairs CSG 15

Research and Development

Final Project Report

(Not to be used for LINK projects)

Two hard copies of this form should be returned to:
Research Policy and International Division, Final Reports Unit
DEFRA, Area 301
Cromwell House, Dean Stanley Street, London, SW1P 3JH.
An electronic version should be e-mailed to
Project title / Integrating farm management practices with brown hare conservation in pastural habitats
DEFRA project code / BD 1436
Contractor organisation and location / School of Biological Sciences, University of Bristol
Bristol
Total DEFRA project costs / £ 199523
Project start date / 01/09/97 / Project end date / 31/08/02
Executive summary (maximum 2 sides A4)
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CSG 15 (Rev. 6/02) 4

Project
title / Integrating farm management practices with brown hare conservation in pastural habitats
/ DEFRA
project code / BD 1436

1. Numbers of hares have declined throughout Europe as a result of agricultural intensification, therefore the hare is protected under Appendix III of the Convention of the Conservation of European Wildlife and Natural Habitats (Bern Convention). It is also classed as a 'priority species of conservation concern' by the UK government, and therefore has a Biodiversity Action Plan (BAP). In order to achieve the BAP targets and the effective long-term conservation of this species, ecological research to inform agricultural management policy was needed. We therefore aimed to identify agricultural land management practices that may benefit the hare, which is of conservation concern and of value as a game animal.

2. A questionnaire survey of farmers was used to investigate relationships between the abundance of hares on farmland and current land management, the abundance of a possible competitor (rabbit), and the abundance of two predators (buzzard and fox). Hares were relatively common on arable farms, especially on those with wheat, beet, or fallow land. They were less common on pastural farms, where the likelihood of seeing hares was increased if improved grass, woodland or, in some cases, arable land were present. Hares were seen rarely where foxes were seen frequently. Changes in land management that provide year-round cover and forage may make farms more attractive to hares. To benefit hares, pastural farms should have some woodland, improved grass, and some arable crops; arable farms should have wheat, beet, and fallow land.

3. In order to elucidate habitat-related differences in abundance of hares, we sought functional explanations for variation in abundance. The demography (length and timing of breeding season, litter sizes, incidence of prenatal mortality and participation in breeding), body condition (urinary and serum nitrogen, kidney fat, bone marrow fat, skeletal size and weight), and dietary quality (ash, protein, fat, fibre, carbohydrates, and total weight and energy of stomach contents) of hares from arable and pastural areas were compared. In pastural areas, a lower proportion of adult males participated in breeding, and a lower proportion of adult females were lactating than in arable areas. Hares from pastural areas were smaller, lighter, and had less kidney fat than those from arable areas, but dietary quality was similar. Thus hares in low-density populations from pastural areas were able to obtain a good-quality diet, but unable to maintain good body condition. Energy expenditure in pastural areas must be high, due to increased disturbance by predators or humans, or due to wetter weather. Pasture is a sub-optimal habitat for hares, where recruitment, and probably survival, is low. The demographic differences help to explain the observed differences in density of hares in arable and pastural habitats. Efforts to conserve the hare should focus on increasing survival of adults and leverets.

4. Since body condition is poor in pastural areas, we predict that adult survival is low. We used radio tracking to investigate survival, dispersal, home range size, and habitat selection in hares at a pastural study site. We aimed to discover what habitat factors, if any, are limiting populations of hares in pastural areas, and how populations could be increased by habitat management. We found that adult and subadult survival was low compared to that described in the literature for arable areas. However, home ranges were relatively small compared to those described in arable areas, and were smallest during seasons when food availability was lowest. Home ranges of individual hares overlapped. These results suggest that foraging habitat quality did not limit numbers of hares at our study site, and that food availability is not generally a limiting factor for hares in pastural areas. Seasonal changes in habitat selection by hares showed that they use a variety of habitats for feeding and resting throughout the year. Habitats are selected and avoided in various seasons based on both food availability and vegetation height. The four main habitat types at our study site (arable crops, ley, pasture without livestock, and pasture with livestock) were all selected during at least one season. The main factor limiting the growth of populations of hares in pastural areas appears to be low adult survival. Hares in pastural areas, which are in poor condition, may be more susceptible to death by predation, disease, exposure, and hunting by humans than hares in arable areas, but it is unclear what the main causes of death are in adult hares. Conservation measures for hares in pastural areas should be targeted towards increasing adult survival, but it is unlikely that this could be achieved by improving habitat quality.

5. We derived population models based on demographic parameters from the literature and measured in hares from arable and pastural habitats. We aimed to quantify the importance of adult survival in determining population growth rate in both arable and pastural habitats. We used survival rates of hares in arable areas obtained by radio tracking, and our own data from radio tracking hares in a pastural site, to calculate mean lifespan in both habitats. Hares from arable areas are expected to survive on average for over five years, while hares at our pastural study site are expected to survive for just over two years. Our model populations of hares in arable habitats tend to increase, while those in pastural habitats decrease. Perturbation analysis revealed that in both arable and pastural habitats, the growth rate of populations of hares is much more sensitive to changes in adult survival than to changes in any other survival or fecundity parameter. Since the BAP target is to double numbers of hares by 2010, we determined the time needed for the model population to double. Model populations in arable areas could double in 3-4 years, and changing demographic parameters had little effect on the doubling time, since growth rates were already high in the default model. Populations in pastural areas were in decline, and therefore never doubled. Even if adult survival was increased by 15 percent, and adult fecundity was doubled for hares in pastural areas, the annual population growth rate remained < 1, so populations remained in decline. Our population models could be made more accurate by collecting more data on fecundity and survival and thereby reducing the need to use data from the literature. However, despite some gaps in the data from England and Wales, the perturbation analysis remains valid, and clearly, the most effective way to increase populations of hares is to increase adult survival. Conservation efforts should therefore focus on adult survival, although it is unclear how increases in survival could actually be achieved. It is highly unlikely that populations of hares in pastural areas could be doubled by 2010 to achieve the BAP target. Conservation measures in pastural areas will be unsuccessful unless they result in large increases in both survival and recruitment in populations of hares.

6. Achieving conservation targets by focusing on changes in specific demographic parameters such as survival is difficult. Habitat modification encouraged by financial incentives is suggested in the BAP as a possible way to achieve the target for the hare. We used data from a national hare survey in conjunction with our own questionnaire data, to quantify relationships between density of hares and habitat features, and to assess the feasibility of using agri-environment incentives to achieve the BAP target. Multiple linear regression techniques were used to quantify the significance and strength of relationships between extant hare numbers, current landscape structural characteristics (farm size, field size, habitat density and habitat diversity) and habitat management practices (areas of crops and grassland, areas of other habitats, and management of fallow land) on farms. The strongest and most significant associations existed between hare numbers and landscape structural characteristics such as field size and habitat diversity. Such characteristics cannot readily be targeted by agri-environmental incentives, and changes to benefit hares may be detrimental for other species of conservation concern. This analysis suggests that the BAP target cannot feasibly be achieved by using financial incentives to encourage habitat modification. Incentives to encourage habitat modification (including increased field size and habitat diversity) in only those areas where the hare population is deemed to be unacceptably low may be more financially efficient in these circumstances.

7. Numbers of hares are much lower in pastural areas of England and Wales than in arable areas. The fact that high numbers of hares are associated with certain farmland habitat types suggests that habitat management may help to increase numbers of hares locally, and the provision of year-round cover and food may benefit hares. However, with current knowledge it seems unlikely that large increases in numbers of hares could be achieved by habitat management. The changes needed in habitat management in order to achieve large changes (e.g. doubling) in populations of hares are either unfeasible, or detrimental to other species of conservation value. Populations of hares in pastural areas participate less in breeding than those in arable areas, and are also in poorer condition, lighter, and smaller. Survival probability of hares, particularly adults, is lower in pastural areas than in arable areas, and adult survival is the most important parameter determining population growth rate in all habitats. Hares which are in poor condition are more susceptible to death by predation, disease, exposure to bad weather conditions, and hunting by humans. However, comparison of dietary quality in hares from arable and pastural areas, and radio tracking hares in pastural areas suggest that enough food is available in pastural habitats, and that populations of hares are unlikely to be limited by food availability in these habitats. Therefore, two important questions pertaining to hares in pastural habitats remain to be answered: firstly, why is their body condition so poor? and secondly, what is causing the death of adult hares? In other words, what are the ultimate and proximate causes of the poor survival of adult hares in pastural areas?

Poor body condition could be caused by constant exposure to inclement weather conditions, for instance the frequent precipitation which is common in pastural areas of England and Wales. It could also be caused by exposure to disease. There may be an interaction between these two factors, since many diseases of hares are more common at wet times of year and in wet areas. Poor body condition could also be due to high levels of activity caused by disturbance by predators or by humans (during mechanised agricultural practices or during hunting). Our research suggests that poor body condition is not caused by poor dietary quality or by poor foraging habitat quality. The most likely proximate causes of death in adult hares are exposure, disease, predation, traumatic injury linked to agricultural practices, and hunting. Our research provides some direct and indirect evidence for the occurrence of each of these except for exposure.

Further research is needed if the relative importance of each of the possible ultimate and proximate causes of death in adult hares is to be evaluated. Our research has shown that habitat management can benefit populations of hares, but that the attainment of the BAP target through habitat modification alone will be very difficult for this species.

CSG 15 (Rev. 6/02) 4

Project
title / Integrating farm management practices with brown hare conservation in pastural habitats
/ DEFRA
project code / BD 1436
Scientific report (maximum 20 sides A4)
To tab in this section press the tab key and the Control key together
Press the DOWN arrow once to move to the next question.

CSG 15 (Rev. 6/02) 4

Project
title / Integrating farm management practices with brown hare conservation in pastural habitats
/ DEFRA
project code / BD 1436

1 Introduction

Throughout its geographical range in Europe, the hare Lepus europaeus is most common in intensively farmed arable areas and less common in non-arable areas (Tapper & Parsons 1984; Klansek et al. 1998). However, populations decline if agriculture becomes too intensive. Records of numbers of hares shot suggest a decline throughout Europe (Pielowski & Pucek 1976; Tapper, 1992), as a result, the hare is protected under the Bern Convention (Anonymous 1979), and has a UK Biodiversity Action Plan (BAP; Anonymous 1995). In the BAP, factors causing the species' decline are given as: conversion of grass to arable, loss of habitat diversity in the agricultural landscape, and changes in planting and cropping regimes, such as a move from hay to silage, and autumn planting of cereals. The ultimate cause of the decline in of hares is believed to be agricultural intensification (Tapper & Barnes 1986; Slamečka 1991), but the proximate cause is unclear. Populations may be limited by low quality or scarcity of resources (Frylestam 1980a; Hackländer, Tataruch & Ruf 2002), predation by the fox Vulpes vulpes (Lindström et al. 1994), or climate (Eiberle 1984). In the BAP, the population estimate for the hare is 817 500 - 1 250 000; the target is to double numbers of hares in Britain by 2010. The aim of BD1436 was to describe changes in agricultural management which might benefit hares in England and Wales and contribute to the achievement of the BAP target. As detailed in sections 2-6 of this report, several approaches were taken to collect data needed to achieve the overall aim.