Land-sparing agriculture sustains higher levels of avian functional diversity than land sharing

The ecological impacts of meeting rising demands for food production can potentially be mitigated by two competing land-use strategies: off-setting natural habitats through intensification of existing farmland (land sparing), or elevating biodiversity within the agricultural matrix via the integration of 'wildlife-friendly' habitat features (land sharing). However, a key unanswered question is whether sparing or sharing farming would best conserve functional diversity, which can promote ecosystem stability and resilience to future land-use change. Focusing on bird communities in tropical cloud forests of the Colombian Andes, we test the performance of each strategy in conserving functional diversity. We show that multiple components of avian functional diversity in farmland are positively related to the proximity and extent of natural forest. Using landscape and community simulations, we also show that land-sparing agriculture conserves greater functional diversity and predicts higher abundance of species supplying key ecological functions than land sharing, with sharing becoming progressively inferior with increasing isolation from remnant forest. These results suggest low-intensity agriculture is likely to conserve little functional diversity unless large blocks of adjacent natural habitat are protected, consistent with land sparing. To ensure the retention of functionally diverse ecosystems, we urgently need to implement mechanisms for increasing farmland productivity whilst protecting spared land

Biogeographic multi‐species occupancy models for large‐scale survey data

Ecologists often seek to infer patterns of species occurrence or community structure from survey data. Hierarchical models, including multi-species occupancy models (MSOMs), can improve inference by pooling information across multiple species via random effects. Originally developed for local-scale survey data, MSOMs are increasingly applied to larger spatial scales that transcend major abiotic gradients and dispersal barriers. At biogeographic scales, the benefits of partial pooling in MSOMs trade off against the difficulty of incorporating sufficiently complex spatial effects to account for biogeographic variation in occupancy across multiple species simultaneously. We show how this challenge can be overcome by incorporating preexisting range information into MSOMs, yielding a “biogeographic multi-species occupancy model” (bMSOM). We illustrate the bMSOM using two published datasets: Parulid warblers in the United States Breeding Bird Survey and entire avian communities in forests and pastures of Colombia's West Andes. Compared with traditional MSOMs, the bMSOM provides dramatically better predictive performance at lower computational cost. The bMSOM avoids severe spatial biases in predictions of the traditional MSOM and provides principled species-specific inference even for never-observed species. Incorporating preexisting range data enables principled partial pooling of information across species in large-scale MSOMs. Our biogeographic framework for multi-species modeling should be broadly applicable in hierarchical models that predict species occurrences, whether or not false absences are modeled in an occupancy framework

Mass–abundance scaling in avian communities is maintained after tropical selective logging

Selective logging dominates forested landscapes across the tropics. Despite the structural damage incurred, selectively logged forests typically retain more biodiversity than other forest disturbances. Most logging impact studies consider conventional metrics, like species richness, but these can conceal subtle biodiversity impacts. The mass–abundance relationship is an integral feature of ecological communities, describing the negative relationship between body mass and population abundance, where, in a system without anthropogenic influence, larger species are less abundant due to higher energy requirements. Changes in this relationship can indicate community structure and function changes. We investigated the impacts of selective logging on the mass–abundance scaling of avian communities by conducting a meta‐analysis to examine its pantropical trend. We divide our analysis between studies using mist netting, sampling the understory avian community, and point counts, sampling the entire community. Across 19 mist‐netting studies, we found no consistent effects of selective logging on mass–abundance scaling relative to primary forests, except for the omnivore guild where there were fewer larger‐bodied species after logging. In eleven point‐count studies, we found a more negative relationship in the whole community after logging, likely driven by the frugivore guild, showing a similar pattern. Limited effects of logging on mass–abundance scaling may suggest high species turnover in logged communities, with like‐for‐like replacement of lost species with similar‐sized species. The increased negative mass–abundance relationship found in some logged communities could result from resource depletion, density compensation, or increased hunting; potentially indicating downstream impacts on ecosystem functions. Synthesis and applications. Our results suggest that size distributions of avian communities in logged forests are relatively robust to disturbance, potentially maintaining ecosystem processes in these forests, thus underscoring the high conservation value of logged tropical forests, indicating an urgent need to focus on their protection from further degradation and deforestation

Observations of Neutron-Capture Elements in the Early Galaxy

Neutron-capture elements in low metallicity Galactic halo stars vary widely both in overall contents and detailed abundance patterns. This review discusses recent observational results on the n-capture elements, discussing the implications for early Galactic nucleosynthesis of: (a) the star-to-star ``bulk'' variations in the n-capture/Fe abundance ratios; (b) the distinct signature of rapid n-capture synthesis events in many (most?) of the lowest metallicity stars; (c) the existence of metal-poor stars heavily enriched in the products of slow n-capture synthesis reactions; and (d) the now-routine detection of radioactive thorium (and even uranium in one and possibly two cases) in the spectra of metal-poor stars.Comment: 8 pages, 3 figures; To appear in the Proceedings of the 7th International Conference on Nuclei in the Cosmo

The yields of r-process elements and chemical evolution of the Galaxy

The supernova yields of r-process elements are obtained as a function of the mass of their progenitor stars from the abundance patterns of extremely metal-poor stars on the left-side [Ba/Mg]-[Mg/H] boundary with a procedure proposed by Tsujimoto and Shigeyama. The ejected masses of r-process elements associated with stars of progenitor mass $M_{ms}\leq18M_{\odot}$ are infertile sources and the SNe II with 20$M_{\odot}\leq M_{ms}\leq 40M_{\odot}$are the dominant source of r-process nucleosynthesis in the Galaxy. The ratio of these stars 20$M_{\odot}\leq M_{ms}\leq40M_{\odot}$ with compared to the all massive stars is about $\sim$18%. In this paper, we present a simple model that describes a star's [r/Fe] in terms of the nucleosynthesis yields of r-process elements and the number of SN II explosions. Combined the r-process yields obtained by our procedure with the scatter model of the Galactic halo, the observed abundance patterns of the metal-poor stars can be well reproducedComment: 7 pages, 6 figures, Accepted for publication in Astrophysics and Space Scienc

Diasporic Security and Jewish Identity

This paper explores the relationship between identity and security through an investigation into Jewish diasporic identity. The paper argues that the convention of treating identity as an objective referent of security is problematic, as the Jewish diaspora experience demonstrates. The paper presents a new way of conceptualizing identity and security by introducing the concept of diasporic security. Diasporic security reflects the geographical experience of being a member of a trans-state community, of having a fluid identity that is shaped by sometimes contradictory discourses emanating from a community that resides both at home and abroad. In introducing the concept of diasporic security, the paper makes use of literature in Diaspora Studies, Security Studies, recent works in contemporary political theory and sociology, and Woody Allen's film, Deconstructing Harry (1997)

Close to the edge:Predation risks for two declining farmland passerines

Data on the breeding success of two crop-nesting passerines, Skylark Alauda arvensis and Yellow Wagtail Motacilla flava, were collected in relation to linear features within and surrounding arable crops. Both species were found to experience high rates of nest predation with increased proximity to field boundaries, although the exact nature of the relationship differed with species and, in the case of Skylark, with boundary type. Most nest losses were attributable to predation. During 2006 video cameras deployed on Skylark nests showed that all recorded predation was by mammals of various species, and that these were most active in or around grass margins. The results suggest that further research is needed into ways of minimizing negative impacts of predation on Skylarks. Possible solutions discussed include concentrating Skylark Plots in the field centres away from grass margins and promoting Skylark Plots in fields without grass margins in future agri-environmental schemes

Beyond ecological traps:perceptual errors and undervalued resources

Ecological traps arise when animals choose to settle in poor-quality habitats, leading to a reduction in their survival or productivity. Although this phenomenon has received comprehensive theoretical treatment in the recent literature, the corollary of the ecological trap (when animals choose to avoid good-quality habitats) is rarely discussed. Failure to recognize high-quality sites could influence the ability of a population to reach its threshold size. An exploration of this phenomenon brings new insights into existing cases of ecological traps. By considering the full range of pitfalls faced during settlement, the relationship between habitat quality and population size might become clearer. We argue here that an improved understanding of factors determining the colonization of high-quality sites could aid conservationists in mitigating the damaging effects of maladaptive habitat selection

Likely effects of construction of Scroby Sands offshore wind farm on a mixed population of harbour Phoca vitulina and grey Halichoerus grypus seals

Scroby Sands offshore wind farm was built close to a haul-out and breeding site for harbour seal, a species of conservation concern. An aerial survey programme conducted during a five-year period spanning wind farm construction, revealed a significant post-construction decline in haul-out counts. Multivariate model selection suggested that the decline was not related to the environmental factors considered, nor did it mirror wider population trends. Although cause and effect could not be unequivocally established, the theoretical basis of hearing in pinnipeds and previous studies suggested that extreme noise (to 257dB re 1μ Pa @ 1m) generated by pile-driving of turbine bases led to displacement of seals. A lack of full recovery of harbour seal during the study was also linked to their sensitivity to vessel activity and/or rapid colonisation of competing grey seal. Any impact of offshore wind farm development upon pinnipeds would be much reduced without pile-driving