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Context

Climate and land-use change have led to disturbance regimes in many ecosystems without a historical analog, leading to uncertainty about how species adapted to past conditions will respond to novel post-disturbance landscapes.

Objectives

We examined habitat selection by spotted owls in a post-fire landscape. We tested whether selection or avoidance of severely burned areas could be explained by patch size or configuration, and whether variation in selection among individuals could be explained by differences in habitat availability.

Methods

We applied mixed-effects models to GPS data from 20 spotted owls in the Sierra Nevada, California, USA, with individual owls occupying home ranges spanning a broad range of post-fire conditions after the 2014 King Fire.

Results

Individual spotted owls whose home ranges experienced less severe fire (<?5% of home range severely burned) tended to select severely burned forest, but owls avoided severely burned forest when more of their home range was affected (~ 5–40%). Owls also tended to select severe fire patches that were smaller in size and more complex in shape, and rarely traveled?>?100-m into severe fire patches. Spotted owls avoided areas that had experienced post-fire salvage logging but the interpretation of this effect was nuanced. Owls also avoided areas that were classified as open and/or young forest prior to the fire.

Conclusions

Our results support the hypothesis that spotted owls are adapted to historical fire regimes characterized by small severe fire patches in this region. Shifts in disturbance regimes that produce novel landscape patterns characterized by large, homogeneous patches of high-severity fire may negatively affect this species.

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2.
Natural populations of guppies were subjected to an episode of directional selection that mimicked natural processes. The resulting rate of evolution of age and size at maturity was similar to rates typically obtained for traits subjected to artificial selection in laboratory settings and up to seven orders of magnitude greater than rates inferred from the paleontological record. Male traits evolved more rapidly than female traits largely because males had more genetic variation upon which natural selection could act. These results are considered in light of the ongoing debate about the importance of natural selection versus other processes in the paleontological record of evolution.  相似文献   
3.
Municipal solid waste (MSW) compost is readily available in eastern Canada and may be a good source of fertility. A 3-year experiment evaluated the effects of MSW compost and fertilizer on soil fertility, elemental composition and yield of potato (Solanum tuberosum L.) grown in a sandy loam soil. Three rates of compost (MSW1, MSW2, and MSW3), one rate of fertilizer (NPK), and one mixture of 1/2 MSW1 compost and 1/2 NPK fertilizer were applied annually to plots in a three-crop rotation; each year the MSW1 rate attempted to match the rate of P applied in the NPK treatment. Mehlich-3 extracts were evaluated for 11 elements at two soil depths (0?C15 and 15?C30 cm). Potato shoots and roots or whole plants were assessed for 16 elements. Treatments had no consistent significant influence on marketable tuber yields although the NPK treatment produced mathematically the highest yields. After 3 years, treatments had influenced soil concentrations of K, Ca, S, Cu, Zn, and Na in Mehlich-3 extracts at the 0?C15 cm depth, but only the concentration of Na at the 15?C30 cm depth. The concentration of Mg in the plant tissue was consistently highest in plants fertilized with NPK; this treatment also produced higher Mn concentrations in the last 2 years. Shoot Cu concentrations were highest in the MSW3 plots. The compost did not increase heavy metal concentrations in shoot, root or whole-plant tissue and would be safe to use at agronomic rates of application.  相似文献   
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