Does a long‐term shift in Wood Stork diet foreshadow adaptability to human‐induced rapid environmental change?

To preserve biodiversity, identifying at‐risk populations and developing conservation plans to mitigate the effects of human‐induced rapid environmental change (HIREC) are essential. Changes in diet, especially for food‐limited species, can aid in detecting populations being impacted by HIREC, and characterizing the quality, abundance, and temporal and spatial consistency of newly consumed food items may provide insight concerning the likelihood of a species persisting in a changing environment. We used Wood Storks (Mycteria americana) nesting in the Florida Everglades as a model system to study the possible effects of HIREC on a food‐limited population. We compared the diets of Wood Storks in 2013 and 2014 with those reported during the 1970s before major anthropogenic activities affected the Everglades system and prey availability. Wood Storks in our study consumed more large‐bodied sunfish species (Lepomis spp.), fewer native marsh fishes, and more non‐native fish species than during the 1970s. Large sunfish and non‐native fish are relatively rare in the drying pools of Everglades marshes where storks traditionally forage, suggesting that Wood Storks may be using novel foraging habitats such as created wetlands (i.e., canals and stormwater ponds). Although created wetlands have long hydroperiods conducive to maintaining large‐bodied fishes and could provide alternative foraging habitat when prey availability is reduced in natural marshes, additional studies are needed to determine the extent to which these wetlands are used by Wood Storks and, importantly, the quality of prey items potentially available to foraging Wood Storks in created wetlands.     

Central Place Foraging in Nonpatchy Habitats

This paper deal with a model of optimal foraging in a habitat with arbitrary food distribution. It takes into account an arbitrary risk cost related to the distance to the animal's nest. Food acquisition and risk cost are accounted for in common units of fitness. The resulting problem is solved in the context of Calculus of Variations. The optimal duration of absence from the nest and the optimal spatial allocation of foraging time are obtained: the optimal strategy leads to separate the habitat into a region to exploit and a region to ignore. The definition of these two distinct regions depends on the relative importance of risk and food availability. With realistic risk costs, the resulting strategy indicates a highly selective behaviour when far from the nest, as observed in field studies. The model is also extended to take account of the need of returning to the nest to guard it or to feed the young.     

Stress-shielding induced bone remodeling in cementless shoulder resurfacing arthroplasty: a finite element analysis and in vivo results

Cementless surface replacement arthroplasty (CSRA) of the shoulder was designed to preserve the individual anatomy and humeral bone stock. A matter of concern in resurfacing implants remains the stress shielding and bone remodeling processes. The bone remodeling processes of two different CSRA fixation designs, conical-crown (Epoca RH) and central-stem (Copeland), were studied by three-dimensional (3-D) finite element analysis (FEA) as well as evaluation of contact radiographs from human CSRA retrievals. FEA included one native humerus model with a normal and one with a reduced bone stock quality. Compressive strains were evaluated before and after virtual CSRA implantation and the results were then compared to the bone remodeling and stress-shielding pattern of eight human CSRA retrievals (Epoca RH n=4 and Copeland n=4). FEA revealed for both bone stock models increased compressive strains at the stem and outer implant rim for both CSRA designs indicating an increased bone formation at those locations. Unloading of the bone was seen for both designs under the central implant shell (conical-crown 50–85%, central-stem 31–93%) indicating high bone resorption. Those effects appeared more pronounced for the reduced than for the normal bone stock model. The assumptions of the FEA were confirmed in the CSRA retrieval analysis which showed bone apposition at the outer implant rim and stems with highly reduced bone stock below the central implant shell. Overall, clear signs of stress shielding were observed for both CSRAs designs in the in vitro FEA and human retrieval analysis. Especially in the central part of both implant designs the bone stock was highly resorbed. The impact of these bone remodeling processes on the clinical outcome as well as long-term stability requires further evaluation.     

Fairy wrasses perceive and respond to their deep red fluorescent coloration

Fluorescence enables the display of wavelengths that are absent in the natural environment, offering the potential to generate conspicuous colour contrasts. The marine fairy wrasse Cirrhilabrus solorensis displays prominent fluorescence in the deep red range (650–700 nm). This is remarkable because marine fishes are generally assumed to have poor sensitivity in this part of the visual spectrum. Here, we investigated whether C. solorensis males can perceive the fluorescence featured in this species by testing whether the presence or absence of red fluorescence affects male–male interactions under exclusive blue illumination. Given that males respond aggressively towards mirror-image stimuli, we quantified agonistic behaviour against mirrors covered with filters that did or did not absorb long (i.e. red) wavelengths. Males showed significantly fewer agonistic responses when their fluorescent signal was masked, independent of brightness differences. Our results unequivocally show that C. solorensis can see its deep red fluorescent coloration and that this pattern affects male–male interactions. This is the first study to demonstrate that deep red fluorescent body coloration can be perceived and has behavioural significance in a reef fish.     

Land-use changes assessed by overlay or mosaic methods: Which method is best for management planning?

Environmental planning must determine management practices for a given territory based on the landscape processes that have occurred over time and their consequences. Therefore, environmental planning decisions must be based on strong empirical evidence that can be easily understood by all involved parties. Several studies have highlighted the methodological deficiencies that occur when obtaining and interpreting such issues, particularly in heterogeneous landscapes with complex interactions. In this paper, we evaluated two methodological approaches that are used in management planning, land use/cover change (LUCC) and mosaic change (MC) to compare their effectiveness and suitability for supporting decision-making. We applied these methods to the coastal landscape of São Sebastião Island, Brazil, which has undergone many changes in the last 50 years. For two years, land use/cover maps were produced using GIS and assessed according to changes in landscape elements (LUCC) and boundaries (MC). Overall, the LUCC failed to identify sets with similar structural heterogeneities in the landscape. However, the LUCC is easier for stakeholders to understand and apply than the MC. The MC method better presented the evolution of the relationship between the landscape elements and heterogeneity.     

The evolution of primate communities and societies in Madagascar

During their 120 to 165 million years of isolation, the flora and fauna of Madagascar evolved, to a large extent, independently of the African mainland.¹ In contrast to other oceanic islands, Madagascar is large enough to house the major components of tropical ecosystems, allowing tests of evolutionary hypotheses on the level of complete communities. Taking lemurs, the primates of Madagascar, as an example, evolutionary hypotheses correctly predict the organization of their community structure with respect to ecological correlates. Lemur social systems and their morphological correlates, on the other hand, deviate in some respects from those of other primates. Apparently, lemur social systems are influenced by several selection pressures that are weak or rare in other primates. These include variable activity patterns and avoidance of infanticide. The interspecific variation in lemur social systems therefore offers a unique opportunity for a comprehensive study of the determinants of primate social systems.     

Deconstructing occupancy frequency distributions in stream insects: effects of body size and niche characteristics in different geographical regions

1. Occupancy frequency distributions (OFDs) are one means to study species distribution patterns, allowing the delineation of rare and common species. Very few studies have deconstructed entire assemblages by ecological or biological characteristics and subsequently examined OFDs in subgroups of species. 2. The effect of deconstruction of entire assemblages by niche breadth, niche position or body size classes on OFDs in stream insects in three drainage basins was examined. It was hypothesized that OFDs should not vary between different drainage basins, but they should be affected by deconstruction into different niche breadth, niche position or body size classes. 3. The OFDs were typically strongly right‐skewed in all drainage basins. The set of small‐sized species was strongly dominated by rare species, whereas the importance of rare species decreased with increasing body size. Further, while the OFDs of sets of species with marginal niche position or small niche breadth were strongly dominated by rare species, those of species with non‐marginal niche position or large niche breadth showed highly variable degrees of occupancy. The OFDs of non‐marginal species were even uniform in the entire data and one drainage basin, providing partial support to the a priori hypothesis. 4. Niche‐based explanations are likely to account for occupancies of marginal and small‐niched species, whereas the distributions of non‐marginal and broad‐niched species may be not only affected by niche‐based mechanisms but also by spatial dynamics. Deconstruction of OFDs by ecological and biological traits thus showed that the patterns may vary between different subgroups of species.