As human population growth drives increasing food demand, land-use expansion and intensification degrade landscape diversity and imperil species’ survival (Firbank et al. 2008; Rockström et al. 2009). In particular, agricultural landscapes—the largest land-use class in Europe (Ramankutty et al. 2008)—have been subject to significant anthropogenic stress over the past decades, characterized by habitat fragmentation, land consolidation, increased field sizes, and declines in crop diversity. This has led to a reduction in species abundance and richness (Pimm and Raven 2000; Benton et al. 2003; Reidsma et al. 2006). Animals living in these intensively-managed agricultural landscapes must not only contend with landscape degradation per se, but also with seasonally changing human-caused disturbances, e.g. the application of fertilizers and pesticides, and the sudden removal of large parts of the biomass during harvest in autumn (Ullmann et al. 2020). To adjust to the consequences of agricultural practices, changing their behaviour and adjusting their movements are some of the few options available to animals to survive.
Animal movement is a key life-history trait underlying individuals’ survival and fitness, and is influenced by landscape composition and configuration (e.g. Turner et al. 2001; Bennett et al. 2006). For example, it was found that increasing habitat fragmentation and decreasing habitat diversity in agricultural landscapes results in a smaller proportion of dispersing animals (Bonte et al. 2006), changes in habitat choice (Smith et al. 2004; Dolný et al. 2014), and increases home ranges and daily travel distances (Diffendorfer et al. 1995; Schai-Braun and Hackländer 2014; Ullmann et al. 2018). Additionally, these animal movement measures, also depend on seasonal changes in the available vegetation structure (Mayer et al. 2019). However, the behavioural mechanisms underlying the changes in movement patterns, i.e. whether travel distances or utilization ranges increase because of increased fleeing or foraging, remain largely unexplored. One promising avenue to investigating the underlying processes is through the animals’ daily behaviours. Although daily behaviours of free-ranging animals have recently become a matter of interest (Wilson et al. 2006; Grünewälder et al. 2012, Lush et al. 2016), the influence of landscape composition and configuration as well as the corresponding seasonal dynamics on the actual animals’ behavioural modes has rarely been studied.
A landscapes’ composition and configuration can be studied on different scales, e.g. at the habitat scale when looking at an animal’s utilization range and discerning the habitat diversity within that utilization range, and at the landscape scale when looking at the overall landscape complexity in which the animal lives (i.e. simple versus complex agricultural landscapes). Areas of high habitat diversity provide all the resources necessary to satisfy the animals’ needs for food and cover within a small spatial scale (Anderson et al. 2005; Saïd and Servanty 2005), thus shortening the time animals need for travelling between patches and increasing the amount of time available to them, for e.g. resting or social behaviour (Li and Rogers 2004). In contrast, areas of low habitat diversity consist mainly of agricultural crop fields and few other landscape elements, of which only certain patches may provide food, while other, distant ones provide shelter. Areas of low and high habitat diversity might be found in simple and complex landscapes simultaneously, as even simple landscapes still show small areas of high habitat diversity. In general, however, regions with a simple landscape structure consist of large agricultural crop fields that often cover vast areas sparsely interspersed with small (semi-) natural patches. This potentially forces animals to stay in a patch when encountering barriers, or to travel long distances between habitat patches to meet their daily requirements (Ullmann et al. 2018). Regions with a complex landscape structure, on the other hand, generally show smaller agricultural fields and a higher crop diversity, where inhospitable areas are easier to overcome or moved around than in simple landscapes, resulting in less travel time for animals. Hence, the decline in landscape complexity and habitat diversity seemingly leads to an increase in movement and corresponding decrease in resting, which would then result in higher energy expenditure (Mace and Harvey 1983) and ultimately to a decline in body conditions and individual fitness (Daan et al. 1996).
A typical open-habitat species occurring in agricultural landscapes is the European brown hare (Lepus europaeus, hereafter hare). Since the 1960s, hare populations have declined strongly throughout Europe, primarily due to agricultural intensification and an associated decline in landscape diversity (Smith et al. 2005). Hares in less diverse landscapes are less abundant, have smaller survival rates, are lighter, and have smaller litters (Frylestam 1980; Tapper and Barnes 1986). One of the main aspects that might change with declining landscape composition and configuration is resource availability (e.g. food and shelter), which additionally changes throughout the season and influences hares’ spatial movement behaviour (Mayer et al. 2019). Hares forage on cultivated crops, but a high-quality diet also heavily depends on non-cultivated herbs (Reichlin et al. 2006). This need might be exacerbated in the breeding time of female hares, when a high energy demand to milk the offspring coincides with the need of finding good hiding places to deter predators (Hackländer et al. 2002a; Valencak et al. 2009; Mayer et al. 2019).
Here, we investigate whether changes in animals’ behavioural modes are caused by changes in landscape complexity and habitat diversity. We used GPS telemetry with internal tri-axial accelerometers to distinguish between the following behavioural modes of European brown hares: resting, moving, foraging, grooming and standing upright on the hind legs (i.e. vigilance behaviour). We defined foraging behaviour as the search for resources and not necessarily the process of feeding. We analysed landscape complexity by choosing a structurally simple landscape with large fields in northeast Germany and a structurally complex landscape with small fields in southern Germany. From the landscape scale we “zoomed in” to the habitat scale and used each hare’s monthly utilization range to calculate the underlying habitat diversity, in each of the two differently structured landscapes. We related study area (i.e. landscape complexity) and habitat diversity to the hares’ behavioural modes and investigate the relevance of seasonal changes in habitat diversity for sex-specific behavioural responses within certain life-history stages (e.g. mating during spring and summer, versus reproductive pause in late autumn and beginning winter).
Specifically, we hypothesize that:
Hares in diverse habitats move less and have more time to rest, as most of their resources are found within a small spatial scale. Hares in habitats of low diversity rest less and move more frequently, as they must spend more time searching for resources (especially high-quality food items) and travel longer distances.
The effect described in hypothesis 1 scales up to the landscape structure. Hares in simple agricultural landscapes with large fields, spend more time moving than hares in complex agricultural areas with small fields, as resources are more spread out, due to the large field sizes.
The behavioural modes of males and females will change seasonally following important life-history events like reproduction, resulting in increased moving behaviour during mating and more extended resting periods in the non-reproductive period.