Daniel Burgas

Unexpected diversity in socially synchronized rhythms of shorebirds

The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring). The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within- and between-species diversity in incubation rhythms. Between species, the median length of one parent’s incubation bout varied from 1–19 h, whereas period length—the time in which a parent’s probability to incubate cycles once between its highest and lowest value—varied from 6–43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light–dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms.

Raptors as surrogates of biodiversity along a landscape gradient

Summary With biodiversity facing threats, there is a need to improve reserve selection procedures. However, detailed information about different biodiversity measures (e.g. species richness) at potential sites is often lacking, and selecting areas that protect most biodiversity is difficult. To simplify matters, biodiversity surrogate species, that is, species associated with higher biodiversity than average, have been used for area selection. However, consensus about the performance of the surrogate species concept is lacking, and there are few studies investigating potential differences in the effectiveness of multiple predators as surrogates for biodiversity over large spatial scales. We evaluated two avian predators, the northern goshawk Accipiter gentilis and the Ural owl Strix uralensis, as surrogates for biodiversity in the boreal forest biome in Western Finland. We used a study design including nest sites and two reference sites for each nest, the diversity of birds and wood-decaying fungi (polypores). We assessed simultaneously whether surrogacy persisted at the landscape level while moving from one vegetation zone to another. We generally found more birds and polypores around the nest sites for both goshawks and Ural owls than at their respective reference sites. However, the goshawk outperformed the Ural owl. Additionally, although biodiversity was found to decrease at the landscape scale as a result of a decrease in vegetation complexity with increasing longitude, the surrogacy efficiency of the raptors remained unchanged. Synthesis and applications. These findings suggest that the surrogate species concept applied to raptors may be an efficient addition to methods for identifying areas of conservation priority, even across vegetation zones. We conclude that protecting areas around raptor nests is a method to consider in order to halt forest biodiversity loss. Finally, sampling biodiversity along diversity and landscape gradients can improve the necessary assessment of surrogate species.

Competitive exclusion within the predator community influences the distribution of a threatened prey species

While much effort has been made to quantify how landscape composition influences the distribution of species, the possibility that geographical differences in species interactions might affect species distributions has received less attention. Investigating a predator-prey setting in a boreal forest ecosystem, we empirically show that large-scale differences in the predator community structure and small-scale competitive exclusion among predators affect the local distribution of a threatened forest specialist more than does landscape composition. Consequently, even though the landscape parameters affecting Siberian flying squirrel (Pteromys volans) distribution (prey) did not differ between nest sites of the predators Northern Goshawks (Accipiter gentilis) and Ural Owls (Strix uralensis), flying squirrels were heterospecifically attracted by goshawks in a region where both predator species were present. No such effect was found in another region where Ural Owls were absent. These results provide evidence that differences in species interactions over large spatial scales may be a major force influencing the distribution and abundance patterns of species. On the basis of these findings, we suspect that subtle species interactions might be a central reason why landscape models constructed to predict species distributions often fail when applied to wider geographical scales.

Local Environment but Not Genetic Differentiation Influences Biparental Care in Ten Plover Populations

Social behaviours are highly variable between species, populations and individuals. However, it is contentious whether behavioural variations are primarily moulded by the environment, caused by genetic differences, or a combination of both. Here we establish that biparental care, a complex social behaviour that involves rearing of young by both parents, differs between closely related populations, and then test two potential sources of variation in parental behaviour between populations: ambient environment and genetic differentiation. We use 2904 hours behavioural data from 10 geographically distinct Kentish (Charadrius alexandrinus) and snowy plover (C. nivosus) populations in America, Europe, the Middle East and North Africa to test these two sources of behavioural variation. We show that local ambient temperature has a significant influence on parental care: with extreme heat (above 40°C) total incubation (i.e. % of time the male or female incubated the nest) increased, and female share (% female share of incubation) decreased. By contrast, neither genetic differences between populations, nor geographic distances predicted total incubation or females share of incubation. These results suggest that the local environment has a stronger influence on a social behaviour than genetic differentiation, at least between populations of closely related species.

Are sacred caves still safe havens for the endemic bats of Madagascar

Despite conservation discourses in Madagascar increasingly emphasizing the role of customary institutions for wildlife management, we know relatively little about their effectiveness. Here, we used semi-structured interviews with 54 adults in eight villages to investigate whether sacred caves and taboos offer conservation benefits for cave-dwelling bats in and around Tsimanampetsotsa National Park, south-west Madagascar. Although some caves were described as sites of spiritual significance for the local communities, most interviewees (c. 76%) did not recognize their present-day sacred status. Similarly, only 22% of the interviewees recognized taboos inhibiting bat hunting and consumption. Legal protection of bats and caves through protected areas was often more widely acknowledged than customary regulations, although up to 30% of the interviewees reported consumption of bats within their communities. Guano extraction was often tolerated in sacred caves in exchange for economic compensation. This may benefit bat conservation by creating incentives for bat protection, although extraction is often performed through destructive and exploitative practices with little benefit for local communities. In view of these results our study questions the extent to which sacred sites, taboos and protected areas offer protection for bats in Madagascar. These results support previous studies documenting the erosion of customary institutions in Madagascar, including the loss of the spiritual values underpinning sacred sites. Given that many Malagasy bats are cave-dwelling species and that most depend on the customary protection of these sites, it is important to obtain a better understanding of the complex interactions between spiritual practices, taboos and protected areas in sustaining bat diversity.

Solving Conflicts among Conservation, Economic, and Social Objectives in Boreal Production Forest Landscapes: Fennoscandian Perspectives

This chapter discusses challenges and possibilities involved in preserving biological diversity and the diversity of ecosystem services in the boreal zone and yet at the same time maintaining intensive timber extraction in boreal forests. Our focus is on Fennoscandian forests at the landscapes level, and we consider economic, social, and ecological in the sustainability of forest management. We provide an outlook to boreal forest ecosystems and their history and an overview of the forestry practices and policies that aim to ensure multifunctionality of Fennoscandian forests, i.e., diversity of efforts on sustaining biodiversity, timber production, and other ecosystem services from forest landscapes. We review the current scientific understanding management effects on the structure and dynamics of the forest at different spatial, and the consequent repercussions on forest biodiversity and ecosystem services. Evidence suggests that many ecosystem services and biodiversity are in conflict with intensive timber production in boreal forests. We therefore present methods for assessing conflicts among alternative forest uses and for finding solutions for conflicts. We conclude the chapter by providing insights for future management aiming at sustainability from economic, ecological, and social perspectives.

Landowner preferences and conservation prioritization: response to Nielsen et al

All material supplied via JYX is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. Landowner preferences and conservation prioritization : response to Nielsen et al Eyvindson, Kyle; Repo, Anna; Burgas Riera, Daniel; Mönkkönen, Mikko