Trophic rewilding presents regionally specific opportunities for mitigating climate change

Large-bodied mammalian herbivores can influence processes that exacerbate or mitigate climate change. Herbivore impacts are, in turn, influenced by predators that place top-down forcing on prey species within a given body size range. Here, we explore how the functional composition of terrestrial large herbivore and carnivore guilds vary between three mammal distribution scenarios: Present-Natural, Current-Day, and Extant-Native Trophic (ENT) Rewilding. Considering the effects of herbivore species weakly influenced by top-down forcing, we quantify the relative influence keystone large herbivore guilds have on methane emissions, woody vegetation expansion, fire dynamics, large-seed dispersal, and nitrogen and phosphorous transport potential. We find strong regional differences in the number of herbivores under weak top-down regulation between our three scenarios with important implications for how they will influence climate change relevant processes. Under the Present-Natural non-ruminant, megaherbivore, browsers were a particularly important guild across much of the world. Megaherbivore extinction and range contraction and the arrival of livestock means large, ruminant, grazers have become more dominant. ENT Rewilding can restore the Afrotropics and Indo-Malay to the Present-Natural benchmark, but causes top-down forcing of the largest herbivores to become common place elsewhere. ENT Rewilding will reduce methane emissions, but does not maximise Natural Climate Solution potential

Understanding species distribution in dynamic populations : a new approach using spatio‐temporal point process models

Funding: EU consolidator’s grant STATEMIG 310820 (SB).Understanding and predicting a species’ distribution across a landscape is of central importance in ecology, biogeography and conservation biology. However, it presents daunting challenges when populations are highly dynamic (i.e. increasing or decreasing their ranges), particularly for small populations where information about ecology and life history traits is lacking. Currently, many modelling approaches fail to distinguish whether a site is unoccupied because the available habitat is unsuitable or because a species expanding its range has not arrived at the site yet. As a result, habitat that is indeed suitable may appear unsuitable. To overcome some of these limitations, we use a statistical modelling approach based on spatio‐temporal log‐Gaussian Cox processes. These model the spatial distribution of the species across available habitat and how this distribution changes over time, relative to covariates. In addition, the model explicitly accounts for spatio‐temporal dynamics that are unaccounted for by covariates through a spatio‐temporal stochastic process. We illustrate the approach by predicting the distribution of a recently established population of Eurasian cranes Grus grus in England, UK, and estimate the effect of a reintroduction in the range expansion of the population. Our models show that wetland extent and perimeter‐to‐area ratio have a positive and negative effect, respectively, in crane colonisation probability. Moreover, we find that cranes are more likely to colonise areas near already occupied wetlands and that the colonisation process is progressing at a low rate. Finally, the reintroduction of cranes in SW England can be considered a human‐assisted long‐distance dispersal event that has increased the dispersal potential of the species along a longitudinal axis in S England. Spatio‐temporal log‐Gaussian Cox process models offer an excellent opportunity for the study of species where information on life history traits is lacking, since these are represented through the spatio‐temporal dynamics reflected in the model.PostprintPeer reviewe

Higher Partial Waves in p+p->p+p+eta near Threshold

Exclusive measurements of the production of eta mesons in the p+p->p+p+eta reaction have been carried out at excess energies of 16 and 37 MeV above threshold. The deviations from phase space are dominated by the proton-proton final state interaction and this influences particularly the energy distribution of the eta meson. However, evidence is also presented at the higher energy for the existence of an anisotropy in the angular distributions of the eta meson and also of the final proton-proton pair, probably to be associated with D-waves in this system interfering with the dominant S-wave term. The sign of the eta angular anisotropy suggests that rho-exchange is important for this reaction.Comment: 16 pages, LaTeX2e, 3 EPS Figures, Updated version, Accepted for publication in Phys. Lett.

Exploration of hyperfine interaction between constituent quarks via eta productions

In this work, the different exchange freedom, one gluon, one pion or Goldstone boson, in constituent quark model is investigated, which is responsible to the hyperfine interaction between constituent quarks, via the combined analysis of the eta production processes, $\pi^{-}p\rightarrow\eta n$ and $\gamma p\rightarrow\eta p$. With the Goldstone-boson exchange, as well as the one-gluon or one-pion exchange, both the spectrum and observables, such as, the differential cross section and polarized beam asymmetry, are fitted to the suggested values of Particle Data Group and the experimental data. The first two types of exchange freedoms give acceptable description of the spectrum and observables while the one pion exchange can not describe the observables and spectrum simultaneously, so can be excluded. The experimental data for the two processes considered here strongly support the mixing angles for two lowest S11 sates and D13 states as about -30 and 6 degree respectively.Comment: 7 pages, 4 figures, 4 table

Mapping opportunities and challenges for rewilding in Europe

Farmland abandonment takes place across the world due to socio-economic and ecological drivers. In Europe agricultural and environmental policies aim to prevent abandonment and halt ecological succession. Ecological rewilding has been recently proposed as an alternative strategy. We developed a framework to assess opportunities for rewilding across different dimensions of wilderness in Europe. We mapped artificial light, human accessibility based on transport infrastructure, proportion of harvested primary productivity (i.e., ecosystem productivity appropriated by humans through agriculture or forestry), and deviation from potential natural vegetation in areas projected to be abandoned by 2040. At the continental level, the levels of artificial light were low and the deviation from potential natural vegetation was high in areas of abandonment. The relative importance of wilderness metrics differed regionally and was strongly connected to local environmental and socio-economic contexts. Large areas of projected abandonment were often located in or around Natura 2000 sites. Based on these results, we argue that management should be tailored to restore the aspects of wilderness that are lacking in each region. There are many remaining challenges regarding biodiversity in Europe, but megafauna species are already recovering. To further potentiate large-scale rewilding, Natura 2000 management would need to incorporate rewilding approaches. Our framework can be applied to assessing rewilding opportunities and challenges in other world regions, and our results could guide redirection of subsidies to manage social-ecological systems

A unitary model for meson-nucleon scattering

In an effective Lagrangian model employing the K-matrix approximation we extract nucleon resonance parameters. To this end we analyze simultaneously all available data for reactions involving the final states $\pi N$, $\pi\pi N$, $\eta N$ and $K \Lambda$ in the energy range $m_N + m_{\pi} \le \sqrt s \le 1.9$ GeV. The background contributions are generated consistently from the relevant Feynman amplitudes, thus significantly reducing the number of free parameters.Comment: Revised version. 60 pages, 17 figures. Two figures and a short discussion (\pi N \to \eta N, K \Lambda amplitudes) added, typos and minor errors in the citations correcte

Photoproduction of pions and properties of baryon resonances from a Bonn-Gatchina partial wave analysis

Masses, widths and photocouplings of baryon resonances are determined in a coupled-channel partial wave analysis of a large variety of data. The Bonn-Gatchina partial wave formalism is extended to include a decomposition of t- and u-exchange amplitudes into individual partial waves. The multipole transition amplitudes for $\gamma p\to p\pi^0$ and $\gamma p\to n\pi^+$ are given and compared to results from other analyses.Comment: 18 pages, 14 figure

P-wave excited baryons from pion- and photo-induced hyperon production

We report evidence for $N(1710)P_{11}$, $N(1875)P_{11}$, $N(1900)P_{13}$, $\Delta(1600)P_{33}$, $\Delta(1910)P_{31}$, and $\Delta(1920)P_{33}$, and find indications that $N(1900)P_{13}$ might have a companion state at 1970\,MeV. The controversial $\Delta(1750)P_{31}$ is not seen. The evidence is derived from a study of data on pion- and photo-induced hyperon production, but other data are included as well. Most of the resonances reported here were found in the Karlsruhe-Helsinki (KH84) and the Carnegie-Mellon (CM) analyses but were challenged recently by the Data Analysis Center at GWU. Our analysis is constrained by the energy independent $\pi N$ scattering amplitudes from either KH84 or GWU. The two $\pi N$ amplitudes from KH84 or GWU, respectively, lead to slightly different $\pi N$ branching ratios of contributing resonances but the debated resonances are required in both series of fits.Comment: 22 pages, 28 figures. Some additional sets of data are adde