ALBERT

Description: Vultures are among the most threatened avian taxa in the world. When vultures aggregate in large numbers to feed, poisoned carcasses can extirpate entire populations at once. In the light of shrinking numbers worldwide, restocking and reintroduction projects, where wild or captive-bred vultures are released back into nature, constitute a crucial management tool, successfully implemented in many countries. However, reestablishment of sustainable vulture populations to their historical ranges remains a serious challenge, especially if the threat of poisoning persists, which is usually the case. In this study, we model the outcome of a restocking project where an initial colony is subject to repeated poisoning events. We use as an example the isolated population of the griffon vulture (Gyps fulvus) in Cyprus. Mathematical considerations and model simulations show that the probability of colony persistence depends on the initial population size and the intensity and frequency of the poisoning incidents. This type of scenario creates an Allee effect that requires a colony to exceed a minimum size in order to survive. Also in this scenario, a sequence of small but frequent poisoning episodes is worse on average than a few large and rare ones of the same cumulative mortality. Future population reinforcement efforts for vultures should focus on the release of adult birds in adequate numbers for the successful establishment of sustainable colonies and should involve a reduction in small but persistent sources of mortality such as the poison baiting of small canids that until now has been neglected by conservation scientists.

Description: The induction of biocrusts through inoculation-based techniques has gained increasing scientific attention in the last 2 decades due to its potential to address issues related to soil degradation and desertification. The technology has shown the most rapid advances in the use of biocrust organisms, particularly cyanobacteria and mosses, as inoculants and biocrust initiators. Cyanobacteria and mosses are poikilohydric organisms – i.e., desiccation-tolerant organisms capable of reactivating their metabolism upon rehydration – that can settle on bare soils in abiotically stressing habitats, provided that selected species are used and an appropriate and customized protocol is applied. The success of inoculation of cyanobacteria and mosses depends on the inoculant's physiology, but also on the ability of the practitioner to identify and control, with appropriate technical approaches in each case study, those environmental factors that most influence the inoculant settlement and its ability to develop biocrusts. This review illustrates the current knowledge and results of biocrust induction biotechnologies that use cyanobacteria or mosses as inoculants. At the same time, this review's purpose is to highlight the current technological gaps that hinder an efficient application of the technology in the field.

Description: Changes in the vegetation of Brazilian Cerrado may occur over time. However, long-term dynamics are not fully understood yet, especially woody plant encroachment (WPE). The objective of this study was to examine changes in vegetation structure in a preserved area in Triângulo Mineiro region, within the southern Brazilian Cerrado domain, over 32 years (1987, 2005, and 2019). We based the study on field and literature surveys, as well as satellite imagery, and hypothesized that, due to the absence of periodic fires or grazing, Cerrado open formations (i.e., grassland or savanna) tend to become denser due to WPE. Shrubby grassland cover assessed in 1987 disappeared in the following periods (from 30.0 % to 0.0 % in 2019) while forest formations increased (from 7.0 % in 1987 to 11.0 % in 2019). Changes between 2005 and 2019 occurred within the stricto sensu cerrado subdivisions, with reduction of sparse cerrado (from 34.2 % to 7.7 %) and an increase in dense cerrado (from 6.9 % to 39.8 %). Normalized difference vegetation index (NDVI) applied for similar periods indicates a progressive increase of values over time (from 1986 (0.61±0.10) to 2004 (0.65±0.06) and 2018 (0.78±0.05)) and corroborates the WPE process. These patterns imply the loss of biodiversity in open plant formation. Another major consequence was the reduction of wetlands and possible impact on water supply. Such patterns are important to support plant management plans for the threatened Cerrado open plant formations.

Description: Close-to-nature management (CTNM) has been proposed as a promising forestry management approach to improve the structure and quality of forests, which integrates wood production and ecological service functions. Research on the effect of CTNM on the univariate and bivariate distribution of the spatial structure of forest stands provides a scientific basis for the evaluation of CTNM implemented in forestry. Here, we analyzed and compared the spatial-structure characteristics of Masson pine (Pinus massoniana) plantations (young, middle-age, and near-mature stages) under CTNM 8 years after selective cutting and unmanaged control. We used univariate and bivariate distribution of three spatial-structure parameters: mingling (M), dominance (U), and uniform-angle index (W). Results showed that the effect of CTNM on spatial structure was more remarkable in middle-aged and near-mature Masson pine forests compared with the young forest. CTNM significantly improved mingling degree and promoted the horizontal distribution, thereby changing from a cluster to a random distribution. Moreover, CTNM improved the proportion of trees with a high mixing degree and random distribution and the proportion of trees having a micro-structure of random distribution with a high degree of mixture and dominance with a high degree of mixture in middle-aged and near-mature Masson pine forest. Overall, the implementation of CTNM 8 years ago showed a positive effect on the improvement of the spatial structure of Masson pine forest, but the present spatial structure is suboptimal. Further implementation of CTNM to adjust the mingling and uniform-angle index is necessary, and CTNM according to this method of frequency distribution of stand structure parameters can improve the success of forest management.

Description: The rapid expansion of urban environments invariably presents a novel series of pressures on wildlife due to changes in external environmental factors. In reptiles, any such changes in temperature are critical since thermoregulation is the key driver in the function of many physiological processes. How reptiles adapt to such changes may vary from those species that are impacted negatively to others that have the behavioural flexibility to exploit new conditions. In this paper we describe retreat site selection, movements and aspects of the thermal ecology of the African lizard Agama agama in urban environments of West Africa. In early evening lizards began movement from late-afternoon core activity areas and ascended the walls of houses for overnight retreats. A high proportion retreated to locations in groups under or on top of warm electrical panels. The thermal potential these panels offered was the attainment of body temperatures equal to or higher than the minimum preferred body temperature (PBT ≈ 36 ∘C in A. agama) and hence increased physiological performance. The lizards that took advantage of the heat sources travelled further each day to and from diurnal activity areas than individuals that spent the night high on walls but not next to heat panels. There were both potential costs (enhanced predation pressures) and benefits (impacts on thermal ecology, retreat site selection) of this behaviour for lizards living in urban environments.

Description: We used a large dataset of greater flamingo chicks banded and measured at Camargue, France, to verify the applicability of discriminant function analysis to sex this species. Males and females sexed genetically differed significantly in all of the morphological characters measured (body mass, tarsus and wing length), with males being significantly larger than females. Although the discriminant rate varied substantially from one year to another, we found that it increased with the sample size of genetically sexed individuals. Our results suggest that discriminant function analysis (DFA) does not provide an efficient tool to sex greater flamingo chicks as these relationship are highly variable across years, requiring the genetic determination of sex on a large number of individuals every year for calibrating the DFA and still providing an overall low accuracy in sex determination. Indeed, conditions at breeding seasons can vary between years and can be considered proximate causes affecting the correct discriminant rate. Like previous studies, we recommend caution in dealing with discriminant equations computed from small datasets, and our simulation suggests that 325 genetically sexed individuals are needed to obtain 80 % correctly classified greater flamingo chicks.

Description: Extensively managed grasslands, particularly in mountain regions, are considered to be one of the most diverse agroecosystems worldwide. Their decline due to land use abandonment affects the diversity of both plants and associated pollinators. Extensive grasslands constitute an important habitat type and food resource for hoverflies (syrphids); however, not much is known about the effects of abandonment on this important pollinator group. In the present study, we investigated how abandonment affects species richness and the composition of syrphids in mountainous meadows. We recorded the richness of vascular plants, vegetation cover, flower cover and the surrounding landscape to examine whether and how syrphids are affected by plant and landscape parameters. We investigated the species richness, abundance and species composition of syrphids by sweep netting and by using observation plots in 18 semidry meadows across two Austrian regions and one Swiss region. For each region, we selected three meadows abandoned for more than 20 years and three annually mown non-fertilized meadows. Abandonment or mowing had no significant effect on the total number of syrphid species or individuals or on the number of aphidophagous and non-aphidophagous species and individuals. However, the total number of species and the number of non-aphidophagous species significantly increased with the increasing number of plant species. The surrounding landscape and other plant parameters showed no association with the assessed syrphid parameters. Although syrphids were unaffected by abandonment, higher syrphid species numbers in response to a higher plant richness in annual mown meadows suggest that the management of mountain meadows is beneficial in preserving syrphid richness.

Description: Differences in food intake and morphological attributes may facilitate the coexistence of detritivorous fish. The present study investigated the possible differences in the feeding strategies of four species of curimatids that inhabit the floodplain of the central Amazon. For this, we determined the diet, daily food cycle, and whether characteristics of the intestine were related to the length of the fish and the amount of detritus consumed. The detritivory was confirmed, and we observed a difference in the foraging time between species. We found differences in the length and weight of the intestine and the relationship of these variables with the length of the fish and the amount of detritus consumed. Our study suggests that despite belonging to the same family and food group, curimatids have characteristics that allow them to consume the detritus in different ways.

Description: Globally, most bare-looking areas in dryland regions are covered by biocrusts which play a crucial role in modifying several soil surface properties and driving key ecosystem processes. These keystone communities face important threats (e.g. climate change) that place their conservation at risk and in turn the sustainability of the ecosystems they inhabit. Therefore, there is an urgent need to develop ecosystem management strategies to ensure their protection. However, to provide a solid path towards biocrust conservation, the understanding by stakeholders and governance structures of the ecological functions of these communities, their role as benefit providers, and the pressures threatening their important effects are indispensable. Whereas the ecological scope of biocrust has been widely studied in the last decades, the social dimension of their role remained unexplored. By reviewing literature in biocrusts from a social–ecological approach, here we identified knowledge gaps and new research areas that need to be addressed in order to produce scientific knowledge that better guides dryland conservation policies and actions. This research agenda is a prerequisite to advance biocrust conservation.

Description: Climate change influences the global and regional distribution of many species. For thermophilic insects, range expansions towards the north and to higher elevations are expected in the course of climatic warming across the Northern Hemisphere. The distribution of the European mantis (Mantis religiosa) has recently expanded from Mediterranean regions in France to Hesse in central Germany. This is interpreted as a response to rising mean temperatures, and further northward expansion is expected to occur with increasing climate warming. In this study, potential changes in the regional distribution across Hesse were modeled for Mantis religiosa using the present distribution and climate across Europe as the baseline. We estimated potential changes in the regional distribution for two time periods until 2080 based on two climate change scenarios. The results showed that the current range of M. religiosa in Hesse is smaller than expected based on its climatic niche, i.e., the distribution is not in equilibrium with the present climate. With climate warming the model predicts an expansion of the potential distribution for the period 2041–2060. For the period 2061–2080, our model predicts, however, a range contraction in spite of continued warming. This unexpected result warrants further investigation in order to elucidate whether the ongoing climate change may have negative consequences for thermophilic species such as M. religiosa.