Differential responses to woodland character and landscape context by cryptic bats in urban environments

© 2015 Lintott et al. Urbanisation is one of the most dramatic forms of land use change which relatively few species can adapt to. Determining how and why species respond differently to urban habitats is important in predicting future biodiversity loss as urban areas rapidly expand. Understanding how morphological or behavioural traits can influence species adaptability to the built environment may enable us to improve the effectiveness of conservation efforts. Although many bat species are able to exploit human resources, bat species richness generally declines with increasing urbanisation and there is considerable variation in the responses of different bat species to urbanisation. Here, we use acoustic recordings from two cryptic, and largely sympatric European bat species to assess differential responses in their use of fragmented urban woodland and the surrounding urban matrix. There was a high probability of P. pygmaeus activity relative to P. pipistrellus in woodlands with low clutter and understory cover which were surrounded by low levels of built environment. Additionally, the probability of recording P. pygmaeus relative to P. pipistrellus was considerably higher in urban woodland interior or edge habitat in contrast to urban grey or non-wooded green space. These results show differential habitat use occurring between two morphologically similar species; whilst the underlying mechanism for this partitioning is unknown it may be driven by competition avoidance over foraging resources. Their differing response to urbanisation indicates the difficulties involved when attempting to assess how adaptable a species is to urbanisation for conservation purposes

The Effect of Minimum Wages on Low Wage Jobs

We estimate the eect of minimum wages on low-wage jobs using 138 prominent state-level minimum wage changes between 1979 and 2016 in the U.S using a dierence-in-dierences approach. We first estimate the eect of the minimum wage increase on employment changes by wage bins throughout the hourly wage distribution. We then focus on the bottom part of the wage distribution and compare the number of excess jobs paying at or slightly above the new minimum wage to the missing jobs paying below it to infer the employment eect. We find that the overall number of low-wage jobs remained essentially unchanged over the five years following the increase. At the same time, the direct eect of the minimum wage on average earnings was amplified by modest wage spillovers at the bottom of the wage distribution. Our estimates by detailed demographic groups show that the lack of job loss is not explained by labor-labor substitution at the bottom of the wage distribution. We also find no evidence of disemployment when we consider higher levels of minimum wages. However, we do find some evidence of reduced employment in tradable sectors. We also show how decomposing the overall employment eect by wage bins allows a transparent way of assessing the plausibility of estimates

Cycles of Demand and Distribution and Monetary Policy in the US Economy

The role of monetary policy on the cyclical behavior of the labor share and capacity utilization in the US economy is studied empirically. Previous estimation results remain robust; the inclusion of the rate of interest does not alter the underlying specification of the distributive demand regime. Next, the role of monetary policy on net borrowing flows for four institutional sectors are analyzed. Interest rate effects appear most important for households. Based on this finding, implications for countercyclical stabilization policy are spelled out. (author's abstract