Is the notion that species interactions are stronger and more specialized in the tropics a zombie idea?

By A. Moles, J. Ollerton. 2016

142 citations recorded by the source corpus.

TREMELY WIDELY ACCEPTED. A range of factors have been proposed to contribute to this gradient, including the greater time since glaciation, the lack of freezing winters and a generally ‘benign’ climate, as well as the high species diversity of tropical habitats, and the subsequent narrower niches in tropical species due to greater ‘species packing’ in those communities (Dobzhansky 1950, MacArthur 1972, Schemske et al. 2009, Salazar & Marquis 2012, Coley & Kursar 2014). These ideas can be traced back to at least the second half of the 19 century; for example Wallace (1878), comparing tropical versus temperate vegetation, wrote that: “In the equable equatorial zone there is no such struggle against climate. Every form of vegetation has become alike adapted to its genial heat and ample moisture, which has probably changed little even throughout geological periods; and the never-ceasing struggle for existence between the various species in the same area has resulted in a nice balance of organic forces. . . The same general causes have led to the filling up of every place in nature with some specially adapted form.” The idea that biotic interactions are more intense in the tropics underpins much of our current thinking about global patterns in ecology. For instance, the higher rates of herbivory, predation, and parasitism on species at low latitudes are thought to have selected for higher levels of defense in tropical species (Dobzhansky 1950, MacArthur 1972, Coley & Aide 1991, Van Alstyne et al. 2001, Pennings & Silliman 2005, Salazar & Marquis 2012). The intensity of biotic interactions in the tropics is also thought to contribute to the high levels of biodiversity in the tropics, through mechanisms such as the Janzen-Connell effect (Janzen 1970, Connell 1971), and through evolutionary arms races (Coley & Kursar 2014). Linked to this is the idea that interactions between species (including both antagonistic and mutualistic relationships) are typically more specialized in the tropics compared to their temperate counterparts. The prevailing argument has been that the ecological niches of species, and therefore the range of other species with which they interact, should be more narrow in tropical communities because they are densely packed with other species (MacArthur 1972, Janzen 1973). However, recent large-scale empirical studies and meta-analyses have tended not to support the traditional understanding of latitudinal gradients in species interactions. In this commentary, we ask whether the notions that species interactions are stronger and more specialized in the tropics are actually supported by empirical evidence.

Subfields: Ecology, Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation

View Paper: https://www.semanticscholar.org/paper/1b4783b098280c5dd262efb83c0bfccd3444cf5a

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In Ecology, Evolution, Behavior and Systematics

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Citations in the corpus

Latitudinal variation in plant chemical defences drives latitudinal patterns of leaf herbivory (2018, background): “However, the generality of these plant–herbivore latitudinal trends has recently been called into question by work showing that latitudinal trends in herbivory and plant defense are in fact highly variable in strength and direction (Moles and Ollerton 2016).”
Pollinator Diversity: Distribution, Ecological Function, and Conservation (2017, background): “…that tropical taxa may more frequently be specialized in their interactions with other taxa because competition for resources (including the species with which they interact) ought to have resulted in the evolution of narrower niche breadths (but see Moles & Ollerton 2016, Vázquez & Stevens 2004).”