A welcome sign of a change in seasons, the year’s first flowers usher in the start of spring. Yet, as the climate warms, some flowers are blooming earlier. Since plants respond to environmental cues, such as temperature, shifts in their annual development has long been considered an effect of climate change. However, significant warming does not always lead to earlier flowering.
Over the past few millions of years, a succession of ice ages has profoundly influenced the geology of Earth’s northerly latitudes. These past events continue to influence our lives today – particularly in the fertile regions we now rely on for agriculture. By tracing the advances and retreats of ice sheets, Dr Alison Anders at the University of Illinois is gaining important new insights into how the landscapes and ecosystems of these regions are intrinsically linked to the geological past. Her team is also revealing how these areas are responding to a changing climate, and to complex human relationships with the land.
Important clues buried within ancient rocks that were deposited on the ocean floor around one billion of years ago could help scientists understand the evolutionary history of life on Earth. Dr Romain Guilbaud and an international team of researchers from the UK and China analysed the chemical composition of these rocky sediments from the Huainan Basin in North China. Their findings demonstrate how changes in ocean chemistry occurring between one billion and 800 million years ago strongly limited the production of atmospheric oxygen, which is a necessary prerequisite for the planet to host complex life.
Beneath our feet lies one of the most biodiverse habitats imaginable – the soil. These highly active underground microbial communities are vital to ecosystem health; they cycle nutrients, form soil structure, and decompose organic matter, among many other functions. The type of microbes that colonise soil is determined by the local plant community and climatic variables, both of which are rapidly changing due to human activity. In a recent study, Dr Carl Rosier of the University of Delaware has explored how urban development disturbs the environmental cycles that influence the types of microbes found in various soil habitats.
Invasive plants can permanently alter ecosystems to promote conditions that support their own persistence. For example, certain invasive grasses can make areas prone to more frequent and larger wildfires, which negatively impact native species but favour fire-resistant invaders. This self-perpetuating process, termed a grass-fire cycle, can be impossible to reverse. Dr Jeanne Chambers of the United States Department of Agriculture’s Rocky Mountain Research Station and her colleagues – Matt Brooks, Matt Germino, Jeremy Maestas, David Board, Matt Jones, and Brady Allred – recently examined how an ecosystem’s resilience to fire and resistance to invasive grasses influence whether a grass-fire cycle will establish. In their paper, the scientists introduced a geospatial tool and decision matrix that incorporate measures of ecological resilience and resistance to invasive grasses for designing management strategies to combat grass-fire cycles.
The destruction of jungle and forest habitats is a serious issue threatening species across the globe. Dr LaRoy Brandt and Maggie Singleton of Lincoln Memorial University studied one such threatened species, Baird’s tapir, in Costa Rica. By identifying the tapir’s tracks and deploying remote trail cameras, the team caught rare glimpses of this threatened species, indicating a return of the native population and an increase in their numbers. The question is, however, is this increase a sign of improving habitats or a result of less favourable forces at play?