Aridity and drought: distinct concepts often conflated in ecological research

Area of Science:

• Ecology
• Climate Change Biology
• Plant Physiology

Background:

• Aridity and drought are key ecological factors driven by water limitation, with projected increases due to climate change.
• Current research often assesses plant drought adaptations by studying patterns along aridity gradients.
• Aridity is a long-term climatic state, while drought is a discrete, anomalous event.

Purpose of the Study:

• To investigate whether patterns observed along aridity gradients are suitable for predicting plant responses to drought.
• To review existing literature on trait-based drought response predictions using aridity gradients.
• To highlight key differences in plant and ecosystem responses to aridity versus drought.

Main Methods:

• Literature review of trait-based studies on plant responses to aridity and drought.
• Conceptual analysis of the differences between aridity and drought.
• Identification of alternative frameworks for drought ecology research.

Main Results:

• Existing literature shows mixed support for using aridity gradients to predict drought responses.
• Significant ecological and physiological differences exist between responses to long-term aridity and short-term drought.
• Conflating aridity and drought may impede accurate ecological predictions.

Conclusions:

• Aridity and drought are distinct phenomena requiring separate research frameworks.
• Relying solely on aridity gradients may not fully capture plant and ecosystem responses to drought.
• Developing new frameworks is crucial for advancing drought ecology and understanding global water limitation.