Explaining the larger seed bank of an invasive shrub in non-native versus native environments by differences in seed predation and plant size.

BACKGROUND AND AIMS: Large, persistent seed banks contribute to the invasiveness of non-native plants, and maternal plant size is an important contributory factor. We explored the relationships between plant vegetative size (V) and soil seed bank size (S) for the invasive shrub Ulex europaeus in its native range and in non-native populations, and identified which other factors may contribute to seed bank variation between native and invaded regions. METHODS: We compared the native region (France) with two regions where Ulex is invasive, one with seed predators introduced for biological control (New Zealand) and another where seed predators are absent (La Réunion). We quantified seed bank size, plant dimensions, seed predation and soil fertility for six stands in each of the three regions. KEY RESULTS: Seed banks were 9-14 times larger in the two invaded regions compared to native France. We found a positive relationship between current seed bank size and actual plant size, and that any deviation from this relationship was probably due to large differences in seed predation and/or soil fertility. We further identified three possible factors explaining larger seed banks in non-native environments: larger maternal plant size, lower activity of seed predators and higher soil fertility. CONCLUSIONS: In highlighting a positive relationship between maternal plant size and seed bank size, and identifying additional factors that regulate soil seed bank dynamics in non-native ranges, our data offer a number of opportunities for invasive weed control. For non-native Ulex populations specifically, management focusing on 'S' (i.e. the reduction of the seed bank by stimulating germination, or the introduction of seed predators as biological control agents) and/or on 'V' (i.e. by cutting mature stands to reduce maternal plant biomass) offers the most probable combination of effective control options.

Evaluation for Bleeding Disorders in Suspected Child Abuse.

Bruising or bleeding in a child can raise the concern for child abuse. Assessing whether the findings are the result of trauma and/or whether the child has a bleeding disorder is critical. Many bleeding disorders are rare, and not every child with bruising/bleeding that may raise a concern for abuse requires an evaluation for bleeding disorders. However, in some instances, bleeding disorders can present in a manner similar to child abuse. Bleeding disorders cannot be ruled out solely on the basis of patient and family history, no matter how extensive. The history and clinical evaluation can be used to determine the necessity of an evaluation for a possible bleeding disorder, and prevalence and known clinical presentations of individual bleeding disorders can be used to guide the extent of laboratory testing. This clinical report provides guidance to pediatricians and other clinicians regarding the evaluation for bleeding disorders when child abuse is suspected.

Globalization and the population structure of Toxoplasma gondii.

Toxoplasma gondii is a protozoan parasite that infects nearly all mammal and bird species worldwide. Usually asymptomatic, toxoplasmosis can be severe and even fatal to many hosts, including people. Elucidating the contribution of genetic variation among parasites to patterns of disease transmission and manifestations has been the goal of many studies. Focusing on the geographic component of this variation, we show that most genotypes are locale-specific, but some are found across continents and are closely related to each other, indicating a recent radiation of a pandemic genotype. Furthermore, we show that the geographic structure of T. gondii is extraordinary in having one population that is found in all continents except South America, whereas other populations are generally confined to South America, and yet another population is found worldwide. Our evidence suggests that South American and Eurasian populations have evolved separately until recently, when ships populated by rats, mice, and cats provided T. gondii with unprecedented migration opportunities, probably during the transatlantic slave trade. Our results explain several enigmatic features of the population structure of T. gondii and demonstrate how pervasive, prompt, and elusive the impact of human globalization is on nature.