Dynamic selective environments and evolutionary traps in human-dominated landscapes

Abstract

Human activities can alter selective environments in ways that can reduce the usefulness of certain ornamental traits as honest signals of individual quality and, in some cases, may create evolutionary traps, where rapid changes in selective environments result in maladaptive behavioral decisions. Using the sexually dichromatic, socially monogamous Northern Cardinal (Cardinalis cardinalis) as a model, we hypothesized that urbanization would erode the relationship between plumage coloration and reproductive success. Because the exotic Amur honeysuckle (Lonicera maackii) provides carotenoids, is a preferred habitat attribute, and increases vulnerability to nest predation, we predicted the presence of an evolutionary trap, whereby the brightest males would achieve the lowest reproductive success. Working at 14 forests in Ohio, USA, 2006-2008, we measured plumage color, monitored reproduction, and quantified habitat within territories. In rural landscapes, the brightest males bred earliest in the season and secured more preferred territories; however, annual reproduction declined with plumage brightness. Coloration of urban males was not associated with territory attributes or reproduction. Female redness across all landscapes was negatively related to reproduction. Poor reproductive performance of otherwise higher-quality males probably resulted from preferences for honeysuckle, which reduces annual reproduction when used as a nesting substrate early in the season. In this way, exotic shrubs prompted an evolutionary trap that was avoided in urban forests where anthropogenic resources disassociated male color and reproductive phenology and success. Our study illustrates how modified selective environments in human-dominated landscapes might shape microevolutionary processes in wild bird populations.

Drivers of Vegetation Species Diversity and Composition in Urban Ecosystems

“…Overall, a more synthetic approach, incorporating multiple interacting processes, is necessary to explain, predict, and manage complex patterns of invasions into urban systems. Regardless of the specific causes, the consequential shifts in plant community can lead to shifts in community function (Hillebrand 2008;Raupp et al 2010;Rodewald 2011;Eviner et al 2012). Ultimately, reducing the diversity of functional traits present in a community may lead to reduced community resilience (i.e., the ability of a community to return to its original, pre-disturbance state) in the face of changing environmental conditions, by narrowing the range of environmental conditions under which the community is pre-adapted to succeed (i.e., the "insurance hypothesis," Yachi and Loreau 1999;MacDougall et al 2013).…”

Native insects and invasive plants encounters

“…Increase in visitation, oviposition, and subsequently better performance of native insects on novel host ultimately may lead to host shift of native insects on the novel invasive plants (Carroll 2007). Invasive plants may act as a suitable niche initially, but the fitness of native insects may reduce over a time period leading to a decline in native insect populations (Ding and Blossey 2009;Keeler and Chew 2008;Rodewald et al 2011). Invasive plants may then act as a population sink or an evolutionary trap for native insects (Keeler and Chew 2008; see also Fig.…”

“…1; Table 2). Leaf damage was compared for introduced and native plants population of Lythrum salicaria (purple loosestrife) from its native (Europe) and invasive range (North America) and was found to be higher on invasive plants in a common garden s Germany a Frenzel and Brandl (2003) Janzen (1985), b Agosta (2006), c Agosta and Klemens (2008), d Gillespie and Wratten (2011), e Castells et al (2014), f Keeler and Chew (2008), g Rodewald et al (2011), h Ding and Blossey (2009), i Graves and Shapiro (2003), j Bowers et al (1992), k Carroll and Boyd (1992), l Chew 1981, m Shapiro (2002, n Jahner et al (2011) Invasive plants perspective…”

Suburban immigrants to wildlands disrupt honest signaling in ultra-violet plumage

“…These signals may be honest because they are dependent on body condition (Kodric-Brown and Brown 1984) or are costly to maintain (Zahavi 1975, Grafen 1990). Human-provided foods are often abundant and ubiquitous, and the introduction of these anthropogenic sources of food can weaken the relationship between plumage coloration and body condition, degrading the advertisement's honesty and creating evolutionary traps whereby once adaptive behaviors become maladaptive (Rodewald et al 2011). For example, in Northern Cardinal (Cardinalis cardinalis), the relationship between plumage brightness and body condition is weaker in suburban areas than in wildlands (Jones et al 2010).…”