What does species richness tell us about functional trait diversity? Predictions and evidence for responses of species and functional trait diversity to land‐use change

Abstract

In the conservation literature on land-use change, it is often assumed that land-use intensification drives species loss, driving a loss of functional trait diversity and ecosystem function. Modern research, however, does not support this cascade of loss for all natural systems. In this paper we explore the errors in this assumption and present a conceptual model taking a more mechanistic approach to the speciesfunctional trait association in a context of land-use change. We provide empirical support for our model's predictions demonstrating that the association of species and functional trait diversity follows various trajectories in response to land-use change. The central premise of our model is that land-use change impacts upon processes of community assembly, not species per se. From the model, it is clear that community context (i.e. type of disturbance, species pool size) will affect the response trajectory of the relationship between species and functional trait diversity in communities undergoing land-use change. The maintenance of ecosystem function and of species diversity in the face of increasing land-use change are complementary goals. The use of a more ecologically realistic model of responses of species and functional traits will improve our ability to make wise management decisions to achieve both aims in specific at-risk systems.

Functional biogeography of oceanic islands and the scaling of functional diversity in the Azores

“…Potential presence of saturation/redundancy, for each grouping, was analyzed by means of the interisland SR-FD relationship. We used linear modeling and evaluated the relevance of a quadratic term (polynomial) to account for potential curvilinear relationships (i.e., indications of saturation) (32,33). The significance of both linear and quadratic models was assessed using the F statistic.…”

Contrasting taxonomic and functional responses of a tropical tree community to selective logging

“…Functional diversity metrics complement taxonomic metrics (Petchey & Gaston 2002;de Bello et al 2010) and are particularly sensitive in the face of species extinctions (Devictor et al 2010). How-ever, there is still no consensus about the relationships between functional diversity metrics and key ecosystem properties and processes (Mayfield et al 2010;Cadotte, Carscadden & Mirotchnick 2011). The performance of functional diversity metrics remains excessively dependent on the a priori choice of traits (Lavorel & Garnier 2002;Lavorel et al 2008;Mouchet et al 2010).…”

“…Recent studies have underlined metrics beyond species richness to assess the relationship between biodiversity and environmental changes (Mayfield et al 2005;Moretti et al 2009;Ville´ger et al 2010). The emerging perception is that conservation and restoration practices can be improved by considering the consequences of management activities for both taxonomic and functional trait diversity (Devictor et al 2010;Mayfield et al 2010), functional traits being the biological attributes of organisms that influence fitness and that shape ecosystem properties (McGill et al 2006;Diaz et al 2007;Suding & Goldstein 2008;Cadotte, Carscadden & Mirotchnick 2011).…”

Effects of intensive agriculture in the structure and functioning of tropical headwater streams

“…Oppositely, forested streams exhibit a higher number of environmental filters for stream algae development, e. g. light deprivation due to canopy cover and low nutrients due to riparian forest buffers, which are the main resources for algal development (STEVENSON et al, 1996). These results are in accord with recent studies that does not support the argument that land use always leads to loss of species and functional traits (MAYFIELD et al, 2010).…”

“…Therefore, the idea that high functional diversity maintains stability in ecosystem functioning are dependent on ecosystem disturbance history, species pool and environmental filter that are different between communities (MAYFIELD et al, 2010;BISWAS;MALLIK, 2011), and therefore should be interpreted with caution on conservation biology and biomonitoring programs of tropical headwater streams.…”