deletions | additions       diff --git a/untitled.tex b/untitled.tex  index 29a4e3f..f83828c 100644  --- a/untitled.tex  +++ b/untitled.tex 
...
\end{abstract}  \section{Introduction}  A central goal in ecology is to identify and understand the processes that influence the distributions of species in space and time. Often, these assembly processes are not directly observable over the proper time scales and must instead by inferred through pattern Levi\cite{Levin_1992}. One approach that is growing in popularity is to use the values and abundances of species traits in a community as evidence for the influence of particular assembly processes \cite{Cavender_Bares_2004, Ackerly_2007, Kraft_2008}. Trait-based approaches have several advantages over strictly taxonomic approaches in that they are quantitative, easily generalizable, and have explicit ties to ecological strategy and performance \cite{MCGILL_2006}(McGill reb\cite{McGill2006}(McGill  et al. 2006, Violle et al. 2007). Unfortunately, inferring process from community trait patterns is not always straightforward because different processes can lead to similar patterns, multiple processes can operate simultaneously, on different traits, and patterns can be affected by exogenous forces. For example: community assembly is sometimes depicted as a balance between environmental filtering, in which species unable to tolerate environmental conditions are filtered out resulting in a clustering of trait values, and niche differentiation, in which competition and limiting similarity result in trait values that are more evenly spaced than expected by chance (e.g. Cavender-Bares et al. 2004, Kraft et al. 2007). But recent work has shown that environmentally-filtered communities can result in random or overdispersed trait patterns (e.g. when there is sufficient within-community environmental heterogeneity) (D’Andrea), and competition-structured communities can result in clustering patterns (Mayfield and Levine 2010). In addition, pattern-based evidence of assembly processes can be can be obfuscated by propagule pressure from adjacent communities (Leibold et al. 2004), or by fluctuating environmental conditions that favor different species over time (Chesson and Warner 1981, Chesson 1994).