LETTER Ecological and evolutionary consequences of niche construction for its agent Grigoris Kylafis* and Michel Loreau Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal, QC H3A 1B1, Canada *Correspondence: E-mail: grigoris.kylafis@mail.mcgill.ca Abstract Niche construction can generate ecological and evolutionary feedbacks that have been underinvestigated so far. We present an eco-evolutionary model that incorporates the process of niche construction to reveal its effects on the ecology and evolution of the niche-constructing agent. We consider a simple plant–soil nutrient ecosystem in which plants have the ability to increase the input of inorganic nutrient as an example of positive niche construction. On an ecological time scale, the model shows that niche construction allows the persistence of plants under infertile soil conditions that would otherwise lead to their extinction. This expansion of plantsÕ niche, however, requires a high enough rate of niche construction and a high enough initial plant biomass to fuel the positive ecological feedback between plants and their soil environment. On an evolutionary time scale, we consider that the rates of niche construction and nutrient uptake coevolve in plants while a trade-off constrains their values. Different evolutionary outcomes are possible depending on the shape of the trade-off. We show that niche construction results in an evolutionary feedback between plants and their soil environment such that plants partially regulate soil nutrient content. The direct benefit accruing to plants, however, plays a crucial role in the evolutionary advantage of niche construction. Keywords Adaptive dynamics, niche construction, nutrient cycling, plant–soil interactions, positive feedback, regulation. Ecology Letters (2008) 11: 1072–1081 INTRODUCTION Niche construction, which portrays organisms as active agents that modify their environment rather than mere passive entities selected by their environment, has received increasing attention in ecology and evolutionary biology during the last decade (Odling-Smee et al. 1996, 2003; Laland & Sterelny 2006). Niche construction is described as a process by which organisms, through their metabolism, ÔengineeringÕ activities (e.g. burrows, nests) and habitat ÔchoiceÕ (e.g. dispersal, immigration), actively modify abiotic and biotic features of their environment. By doing so, they generate feedbacks with their environment that may operate on both ecological and evolutionary time scales (Lewontin 1978; Odling-Smee et al. 2003; Hastings et al. 2007). In its ecological dimension, niche construction is often viewed as synonymous with Ôecosystem engineeringÕ ( Jones et al. 1994). Through their activities, organisms bring about significant, consistent and directed changes to the flows of energy and matter in ecosystems ( Jones et al. 1994, 1997). Ecosystem engineering, however, is mainly focused on the feed-forward ecological effects of engineering activities on other species, and largely ignores feedbacks on the ÔengineerÕ, especially on evolutionary time scales. Niche construction was originally introduced as an evolutionary process that generates selection through an evolutionary feedback between organisms and their selective environ- ment (Lewontin 1978; Odling-Smee et al. 2003; Han et al. 2006). This evolutionary feedback is adaptive provided it enhances the fitness of the organism that generates it (Free & Barton 2007). Adaptive feedback gives the niche- constructing agent the potential to regulate its own environment (Odling-Smee et al. 2003). Theoretical studies of niche construction are in the very beginning of their development. So far, the majority of theoretical models that have been proposed to describe the Ecology Letters, (2008) 11: 1072–1081 doi: 10.1111/j.1461-0248.2008.01220.x Ó 2008 Blackwell Publishing Ltd/CNRS