Spatio-temporal variation in predation by urban domestic cats (Felis catus) and the acceptability of possible management actions in the UK

Urban domestic cat (Felis catus) populations can attain exceedingly high densities and are not limited by natural prey availability. This has generated concerns that they may negatively affect prey populations, leading to calls for management. We enlisted cat-owners to record prey returned home to estimate patterns of predation by free-roaming pets in different localities within the town of Reading, UK and questionnaire surveys were used to quantify attitudes to different possible management strategies. Prey return rates were highly variable: only 20% of cats returned ≥4 dead prey annually. Consequently, approximately 65% of owners received no prey in a given season, but this declined to 22% after eight seasons. The estimated mean predation rate was 18.3 prey cat−1 year−1 but this varied markedly both spatially and temporally: per capita predation rates declined with increasing cat density. Comparisons with estimates of the density of six common bird prey species indicated that cats killed numbers equivalent to adult density on c. 39% of occasions. Population modeling studies suggest that such predation rates could significantly reduce the size of local bird populations for common urban species. Conversely, most urban residents did not consider cat predation to be a significant problem. Collar-mounted anti-predation devices were the only management action acceptable to the majority of urban residents (65%), but were less acceptable to cat-owners because of perceived risks to their pets; only 24% of cats were fitted with such devices. Overall, cat predation did appear to be of sufficient magnitude to affect some prey populations, although further investigation of some key aspects of cat predation is warranted. Management of the predation behavior of urban cat populations in the UK is likely to be challenging and achieving this would require considerable engagement with cat owners

Ranging characteristics of the domestic cat (Felis catus) in an urban environment

In many countries, high densities of domestic cats (Felis catus) are found in urban habitats where they have the potential to exert considerable predation pressure on their prey. However, little is known of the ranging behaviour of cats in the UK. Twenty cats in suburban Reading, UK, were fitted with GPS trackers to quantify movement patterns. Cats were monitored during the summer and winter for an average of 6.8 24 h periods per season. Mean daily area ranged (95 % MCP) was 1.94 ha. Including all fixes, mean maximum area ranged was 6.88 ha. These are broadly comparable to those observed in urban areas in other countries. Daily area ranged was not affected by the cat’s sex or the season, but was significantly larger at night than during the day. There was no relationship between area ranged and habitat availability. Taking available habitat into account, cat ranging area contained significantly more garden and other green space than urban habitats. If cats were shown to be negatively affecting prey populations, one mitigation option for consideration in housing developments proposed near important wildlife sites would be to incorporate a ‘buffer zone’ in which cat ownership was not permitted. Absolute maximum daily area ranged by a cat in this study was 33.78 ha. This would correspond to an exclusory limit of approximately 300–400 m to minimise the negative effects of cat predation, but this may need to be larger if cat ranging behaviour is negatively affected by population densit

Female-Biased Dispersal and Gene Flow in a Behaviorally Monogamous Mammal, the Large Treeshrew (Tupaia tana)

Background: Female-biased dispersal (FBD) is predicted to occur in monogamous species due to local resource competition among females, but evidence for this association in mammals is scarce. The predicted relationship between FBD and monogamy may also be too simplistic, given that many pair-living mammals exhibit substantial extra-pair paternity. Methodology/Principal Findings: I examined whether dispersal and gene flow are female-biased in the large treeshrew (Tupaia tana) in Borneo, a behaviorally monogamous species with a genetic mating system characterized by high rates (50%) of extra-pair paternity. Genetic analyses provided evidence of FBD in this species. As predicted for FBD, I found lower mean values for the corrected assignment index for adult females than for males using seven microsatellite loci, indicating that female individuals were more likely to be immigrants. Adult female pairs were also less related than adult male pairs. Furthermore, comparison of Bayesian coalescent-based estimates of migration rates using maternally and bi-parentally inherited genetic markers suggested that gene flow is female-biased in T. tana. The effective number of migrants between populations estimated from mitochondrial DNA sequence was three times higher than the number estimated using autosomal microsatellites. Conclusions/Significance: These results provide the first evidence of FBD in a behaviorally monogamous species without mating fidelity. I argue that competition among females for feeding territories creates a sexual asymmetry in the costs an

Oxidative discolouration in whole-head and cut lettuce: biochemical and environmental influences on a complex phenotype and potential breeding strategies to improve shelf-life

Lettuce discolouration is a key post-harvest trait. The major enzyme controlling oxidative discolouration has long been considered to be polyphenol oxidase (PPO) however, levels of PPO and subsequent development of discolouration symptoms have not always correlated. The predominance of a latent state of the enzyme in plant tissues combined with substrate activation and contemporaneous suicide inactivation mechanisms are considered as potential explanations for this phenomenon. Leaf tissue physical properties have been associated with subsequent discolouration and these may be influenced by variation in nutrient availability, especially excess nitrogen and head maturity at harvest. Mild calcium and irrigation stress has also been associated with a reduction in subsequent discolouration, although excess irrigation has been linked to increased discolouration potentially through leaf physical properties. These environmental factors, including high temperature and UV light intensities, often have impacts on levels of phenolic compounds linking the environmental responses to the biochemistry of the PPO pathway. Breeding strategies targeting the PALand PPOpathway biochemistry and environmental response genes are discussed as a more cost-effective method of mitigating oxidative discolouration then either modified atmosphere packaging or post-harvest treatments, although current understanding of the biochemistry means that such programs are likely to be limited in nature and it is likely that they will need to be deployed alongside other methods for the foreseeable future

Synthetic and reaction chemistry of heteroatom stabilized boryl and cationic borylene complexes.

The synthesis, spectroscopic and structural characterization of the aryloxy and amino functionalized chloroboryl complexes (eta(5)-C(5)R(5))Fe(CO)(2)B(OMes)Cl (R = H, 2a ; R = Me, 3a) and (eta(5)-C(5)H(5))Fe(CO)(2)B(N(i)Pr(2))Cl (7a) are reported. Compound 2ais shown to be a versatile substrate for further boron-centred substitution chemistry leading to the asymmetric boryl complexes (eta(5)-C(5)H(5))Fe(CO)(2)B(OMes)ER(n) [ER(n) = OC(6)H(4)(t)Bu-4, 2c; ER(n) = SPh, 2d] with retention of the metal-boron bond. The reactivities of 2a, 3a and 7a towards the halide abstraction agent Na[BAr(f)(4)] have also been examined, in order to investigate the potential for the generation of cationic heteroatom-stabilized terminal borylene complexes. The application of this methodology to the mesityloxy derivatives and gives rise to B-F containing products, presumably via fluoride abstraction from the [BAr(f)(4)](-) counter-ion. By contrast, amino-functionalized complex 7a is more amenable to this approach, and the thermally robust terminal aminoborylene complex [(eta(5)-C(5)H(5))Fe(CO)(2)B(N(i)Pr(2))][BAr(f)(4)] (9) can be isolated in ca. 50% yield. The reactivity of 9towards a range of nucleophilic and/or unsaturated reagents has been examined, with examples of addition, protonolysis and metathesis chemistries having been established

Halide abstraction by Na[B{C6H3(CF3)(2)-3,5}4]: Synthesis and structural characterization of the rhodium(I) cations [(eta(6)-arene)Rh(PPh3)(2)](+) (arene = benzene, toluene)

Halide abstraction from [(Ph3P)2Rh(μ-Cl)] 2 by the sodium salt of the weakly coordinating [BArf4]- anion [Arf = C6H 3(CF3)2-3,5] in the presence of excess arene offers a convenient, high-yielding route to the half-sandwich cations [(arene)Rh(PPh3)2]+[BArf4]- [arene = benzene (1), toluene (2)]. Crystalline samples of 1 and 2 are isomorphous [a = 13.1270(2), b = 15.3030(2), c = 17.5760(3) Å, α = 74.620(1), β = 81.533(1), γ = 88.540(1)° for 1] and feature the arene ligand bound to the rhodium atom in η6 fashion. © 2006 Wiley-VCH Verlag GmbH and Co. KGaA