Search

Abstract Over the last decades, numerous natural habitats have been converted into settlement areas, agricultural land, and tree plantations on a large spatial scale. As a result, natural ecosystems have been destroyed. In consequence, many ecosystems exist today as small and geographically isolated remnants. To what extent the original species diversity can persist in such small habitat patches is questionable and strongly depends on the ecology of the species. A prominent example of severe habitat destruction are the species-rich tropical cloud forests of Taita Hills in southern Kenya, which have been deforested almost completely during past decades. However, there still exist typical forest species in the few remaining forest fragments. In this study, we investigate the population ecology and behaviour of two butterfly species present in the cloud forest remnants of Taita Hills, Protogoniomorpha parhassus and Precis tugela. Over a period of one month, we conducted Mark-Release-Recapture to study population sizes and demographic structures, lifespan, dispersal, and behaviour. We found that both species exhibited medium population sizes and are sedentary. However, some individuals performed dispersal throughout the forest. The behaviour of the two species differs: While P. tugela was mostly observed basking with open wings, P. parhassus was mostly sitting under leaves with closed wings. The life span was rather long for butterflies. Implications for insect conservation This study documents the population ecology and behaviour of these two Afrotropical butterflies and underlines the relevance of the conservation of cloud forest remnants to preserve species, which mainly depends on these habitat remnants.

Context Intensification of land-use caused a reduction of ecosystem heterogeneity and diversity, and subsequently led to dramatic decrease of biodiversity. Species depending on dynamic ecosystems are particularly affected from this trend of land-use intensification, landscape homogenization, and the optimization of land-use. Forest species suffer under the intensification of forest management, in the worst case transforming light and heterogeneous deciduous forests into species-poor intensively used deciduous forests optimized for wood production. This lead to the destruction of a mosaic consisting of various successional stages in parallel. Objective In this study we analyse the relevance of forest heterogeneity, forest disturbance and microhabitat preferences of egg oviposition and larval development for a highly endangered butterfly species, Euphydryas maturna. This butterfly species mainly occurs in light and moist deciduous forests, such as riparian forests along mountain streams in northern Austria. Methods We combine detailed field observations with high resolution aerial pictures taken with an Unmanned Aerial Vehicle (UAV) to build ensemble habitat suitability models from GAM, GBM, GLM, and Maxent models. Results We found that egg ovipositions take place exclusively on the tree species Fraxinus excelsior, preferably exposed to the south, partly shaded, and at medium height (3 m). Our habitat suitability models based on high resolution aerial pictures indicate that egg ovipositions are clustered and accumulate along forest edges and at sites with high forest heterogeneity. Conclusion Our study underlines the high relevance and importance of light deciduous forest structures with environmental dynamics creating the preconditions of specific microhabitat structures for endangered species, such as E. maturna. Our study shows that UAV-captured high precision aerial imagery are well suited to optimally connect two spatial scales, the ecosystem and microhabitat scale.

The genetic characteristics of neutral loci in natural populations are shaped by the interplay between genetic drift and gene flow that themselves result from key ecological and evolutionary processes. Because of their influence on population size, habitats characteristics may influence substantially populations' genetic characteristics. However, past studies focused primarily on variables related to habitat quantity while habitat quality was largely overlooked. We therefore combined genetic data to detailed habitat descriptions of three sympatric butterfly species having different ecological needs to quantify the relative contribution of geographic distance and habitat quality/quantity on their genetic characteristics. In all species, the genetic diversity was greater in larger and good quality patches. The genetic differentiation of Lycaena helle (specialist species with limited dispersal) was mostly explained by geographical distances. This effect was dampened by habitat quality as populations inhabiting low quality patches had higher genetic differentiations indicating that the constraints set by local environmental factors increased genetic drift. In Boloria eunomia (specialist species with greater dispersal), the genetic differentiation was only influenced by geographic distance. Finally, in Brenthis ino (more generalist species with greater dispersal), isolation-by-distance was weak and habitat characteristics were unrelated to genetic differentiation. The different effect of habitat quality on these species' genetic characteristics suggests that fundamental ecological traits underpin their response to habitat degradation. In L. helle, a species with major conservation concerns, these results show that preserving habitat quality and connectivity among populations' are important to ensure the maintenance of fully functional metapopulations.

Biodiversity is declining across the globe. Main drivers causing the vanishing of species are habitat destruction and the transformation of former heterogeneous landscapes into homogeneous and intensively used landscapes. Modern land management focuses on the creation of landscape configuration with sharp boundaries between ecosystems. In consequence, transition zones between two ecosystems such as between forest and open grassland are rare, as it counteracts the efficient and commercial use of space. However, there are many species relying on such transition zones between habitats, as the Clouded Apollo butterfly Parnassius mnemosyne. This highly endangered butterfly species occurs in light deciduous forests, interspersed with extensively used grasslands. In our study, we analysed habitat requirements of this butterfly species. We recorded larvae and feeding marks at its primary larval food plant, Corydalis cava, and assessed microhabitat characteristics, including microclimatic conditions. We captured high-resolution multispectral aerial imagery with an unmanned aerial vehicle. We subsequently combined ground-truthing data with information from high resolution aerial pictures to calculate habitat suitability models. We found that P. mnemosyne larvae mainly occur in the transition zone between deciduous light forest and extensively used grasslands with C. cava. Caterpillars of P. mnemosyne are particularly found around trees, basking on foliage and grass to rapidly reach high operation temperatures. Results from Species Distribution Models underline the relevance of transition zones between habitats for P. mnemosyne, and for biodiversity in general. The Clouded Apollo may serve as excellent indicator species for light deciduous forests, and as flagship to promote the conservation and restoration of transition zones between habitats in nature conservation.

Numerous conservation activities in Africa have been of little effect. In this study, we investigate socio-economic trade-offs that might have been overlooked, yet may undermine conservation action in discret pathways. Data was collected in three study sites with fragile forest ecosystems in south-eastern Kenya, through locally adapted structured surveys and semi-structured expert guides. These analyses are drawn from 827 structured surveys and 37 expert interviews, which were done during 2016–2018. We found general coherences between age, gender, ethnicity, indigenous knowledge, formal education, and higher incomes, which shapes forest conservation attitudes. Indigenous knowledge is marginal, and most people with formal education in the rural setting are likely to be young without legal land rights or among the minority with off-farm employment. The reluctance to address historical land injustices and inequitable sharing of entitlements and management authority overrides positive attitudes and intentions towards forest conservation in all three study sites. However, we found considerable discrepancies among the three study sites. For Arabuko Sokoke forest, the awareness of forest conservation was relatively low when compared with the other two study sites. Forests play a major role against the backdrop of resource use in all three regions. But, different ecosystem services are used among the three study sites. For environmental education and communication, internet plays a comparatively minor role. Strategies to preserve forest differ among the three study sites: Reforestation is proposed in cloud forests of Taita Hills and riparian forests, whereas off-farm employment and alternative income sources plays a major role in Arabuko Sokoke forest. Our findings underline that locally specific conservation management is needed to conduct efficient nature conservation, particularly in countries with very heterogeneous ethnicities and environments.

Species respond differently to landscape structures and environmental changes. In nature conservation, however, responses of a few indicator groups are often generalised to the ecosystem level. In this study, we analyse how birds and butterflies respond to identical landscape structures and environmental gradients across a habitat mosaic in southern Kenya. The study area represents natural coastal forest (core and margins) as well as different agro-environments (orchards and pastures), which partly may also be suitable surrogate habitats for forest species. We assessed birds and butterflies during the same time and along identical transects, covering the dry and rainy season. The obtained results indicate that both indicator groups depict habitat types in some aspects similarly but in others in somewhat different ways. Thus, strongest differences in community similarity were visible between forest interior and open landscape (i.e. pastures) for both taxa. The forest community strongly overlapped with orchards for birds but less so for butterflies. Thus, orchards in close geographic context with natural forests might be possible surrogates for certain forest bird species but less so for the little mobile forest butterfly species. The temporal variation in species richness, abundances, and community structures was much stronger for butterflies compared to birds. Thus, seasonality in tropical ecosystems has to be considered when interpreting community structures of butterflies but much less so in birds. In general, birds and butterflies proved to be suitable indicator groups to ecologically assess landscape structures in East Africa, with birds more representing the landscape level and butterflies more the fine-grained habitat scale.

The Kaya forests in Southern Kenya are valuable habitats for rare animal and plant species and provide various ecosystem services. The Kaya forests are also centres of cultural life and are of great relevance to rites, traditions, and the social order of the community of people. During the past decades, these forest remnants become under extreme pressure due to land use and resource exploitation and are in danger of disappearing completely during the next years. This negative trend is progressing with the increasing population density. In addition, the relevance of the former cultural rites is increasingly being forgotten, and with it the relevance of these places. In order to preserve these forest remnants in the long term, it is important to make the population aware of the numerous and valuable ecosystem services, as well as to bring the former cultural life back into the centre of society. A general prerequisite to efficiently conserve Kayas might be the improvement of communication among generations, such as between the elders of Kayas and the youth, as well as among elders from different Kayas to harmonize conservation strategies and the sustainable use of these forest remnants. In addition, strengthening the communication between state institutions and the elders of the individual Kayas might help to find a common strategy to conserve Kaya forests.

The cloud forests of the Taita Hills are valuable refuges for numerous endemic and rare animal and plant species. They also provide various ecosystem services that support subsistence farming. Due to the large-scale destruction and conversion of these species-rich natural forests into subsistence agriculture and plantations of exotic tree species, most of the natural cloud forest habitats have disappeared and ecosystem services have been significantly diminished. Despite numerous conservation initiatives, the destruction of the Taita Hills forest ecosystem continues, which also lowers livelihood quality of the local people. During a workshop with representatives of GOs, NGOs, researchers and representatives of the local community we identified potential factors which are essential to reverse this negative trend. We found that governance structures urgently need to be strengthened, and that the traditional conservation system needs to get transformed and revitalised. The basic prerequisite is a vital communication among generations, especially between the youth and the elders, as well as and improved communication of scientific knowledge to policy makers and the society. Furthermore, it is essential to harmonize stakeholders’ mandates, policies and actions to efficiently restore this unique forest biodiversity hotspot, and to secure livelihood needs for the local people.

Agricultural intensification leads to a strong homogenization of landscapes. Plots have become larger, boundaries of fields straight, and land plots have been cultivated more intensively. Field copses, ruderal areas and hedgerows were removed. As a result, most of these small-scale habitats located at the edges of fields have disappeared. Thus, many potential habitats of plant and animal species have been destroyed, and the permeability of the landscape decreased during the past decades. Landscape homogenization consequently impacts biodiversity and reduces species richness and abundance of many taxa. In this study, we surveyed changes of land cover and landscape configuration on a field-by-field basis, based on historical (1953) and recent (2018) aerial and satellite images. We further compiled data of butterfly diversity for the same time periods and region. Our data show significant decrease of field copses over the past decades. The landscape structure changed towards rather homogenous fields with straight boundaries among single land plots. The expected number of species per sample unit of an assumed species decreased significantly. Particularly butterflies relying on oligotrophic and xerothermic grasslands decreased, as well as sedentary specialist species. In contrast, the proportion of ubiquitous and mobile generalist species increased. This underlines the general trend of faunal homogenization and the loss of specialized and sedentary species, in the wake of landscape homogenization.

Recent studies indicated severe decline of insect diversity and abundance across major parts of Central Europe. Theoretical studies showed that the drivers behind biodiversity loss vary considerably over time. However, these scenarios so far have been insufficiently approved by long-term and large-scale data. In this study we analysed the temporal trends of butterflies and Zygaenid moths across the federal state of Salzburg, northern Austria, from 1920 to 2019. Our study area covers a large variety of habitats and altitudes. Various changes of land use and intensification occurred during and shortly before our studied period, with a first wave of habitat destruction starting in the late 19th century, followed by the deterioration of habitat quality since the mid-20th century. We used 59,870 presence-only data of 168 butterfly and burnet moth species. Each of these species was classified according to ecological characteristics. Break point analyses for non-linear temporal trends in the community composition returned two major time windows. These time windows coincide with periods characterized by severe habitat destruction and the deterioration of habitat quality due to agricultural intensification. We found significant reductions of the proportion of species requiring specific habitats since 1920 and until today. We identified additional break points for species requiring high habitat qualities, endangered butterfly species, and sedentary species, particularly after a main break point in the 1960s. Our findings underline that, apart from habitat destruction, the deterioration of habitat quality is a main driver of biodiversity loss in general. Therefore, nature conservation should focus on maintaining the highest possible habitat quality.

The COVID-19 crisis and the environmental crisis share a range of similarities. Both crises take place on a global scale and affect all aspects of our lives. However, we humans respond differently to these challenges. Here, we compare and comment on characteristics of the COVID-19 crisis and the environmental crisis, explore how far these two crises are comparable, and what we can learn from actions that have been taken against the COVID-19 crisis. We discuss how human societies are affected by the respective crises, and analyze policy makers’ responses and offer pathways to better inform policy. We highlight the role of science, which significantly contributed to decision making throughout the COVID-19 crisis, but seems frequently underrepresented in the environmental crisis. We conclude that there are significant differences between the two crises in terms of perceptibility and thus communicability. While problems and solutions in the COVID-19 crisis are largely linearly correlated, the challenges of the environmental crisis are far more complex and decoupled, and thus appear much more complex and are often only perceived with difficulty by humans. Thus, tackling the environmental crisis is much more challenging than solving the COVID-19 crisis. To overcome the environmental crisis, purely technical approaches for combating symptoms are not sufficient. However, political interests are usually short-term, and do not correspond with the temporal and spatial scales of global change. There is an urgent need to improve institutionalized scientific advisory mechanisms and to empower global policy makers who are independent of local interest groups. Furthermore, we need the sound communication of complex interactions to the general public and the translation of scientific findings into action. One possibility to achieve this is to bring together natural scientists with expertise in biology, climate and geosciences and social scientists, psychologists, and, possibly, artists.