Habitat selection and potential fitness consequences of two early‐successional species with differing life‐history strategies

Abstract

Habitat selection and its relationship to fitness is a fundamental concept in ecology, but the mechanisms driving this connection are complex and difficult to detect. Despite the difficulties in understanding such intricate relationships, it is imperative that we study habitat selection and its relationship with fitness. We compared habitat selection of least terns (Sternula antillarum) and piping plovers (Charadrius melodus) on the Missouri River (2012–2014) to examine the consequences of those choices on nest and chick survival. We hypothesized that plovers and terns would select habitat that minimized the chance of flooding and predation of eggs, chicks, and adults, but that plovers would also select habitat that would provide foraging habitat for their chicks. We developed an integrated habitat selection model that assessed selection across multiple scales (sandbar and nest scales) and directly modeled the effect of selection on nest and chick survival. In general, the species selected habitat in keeping with our hypotheses, such that predation and flooding, in particular, may have been reduced. Sandbar selection had either a negative or no appreciable effect on nest survival for both species across years. Nest‐site selection in 2012 had a generally positive effect on nest survival and chick survival for both terns and plovers, and this trended toward a negative effect by 2014. This result suggested that early selection decisions appeared to be adaptive, but we speculate that relatively high site fidelity and habitat degradation led to reduced benefit over time. Our results highlight the complex nature of habitat selection and its relationship to fitness.

Water depth, vegetation height, and offshore distance are critical factors in nest-site selection for Grey Crowned Crane at Lake Ol' Bolossat, Kenya

“…Knowledge of environmental features that determine habitat quality is critical to developing effective strategies for preserving and restoring natural areas (Hobbs, 2003). Nest-site selection is an integrative behavioural process that evolved to maximize reproductive success (Catlin et. al., 2019).…”

Examining the fluvial alteration hypothesis amidst recovery of the Interior Least Tern (Sternula antillarum)

“…Higher areas provide some protection from flooding, a common cause of nest failure. Although there is some evidence that terns select for nesting sites on sandbars disconnected from banks (Kirsch 1996, Catlin et al 2019, across the styles of river morphology in the nesting range, distance of the nesting site from nearby tree galleries appears to be more important (Lott et al 2013, USFWS 2013. Nests are simple depressions scraped into the sand.…”

“…The reduction in flood magnitudes in the Missouri River reduced the abundance, size, and maintenance of sandbars in unchannelized reaches, and sandbars are rare in the navigation channel during tern nesting season (National Research Council 2011). Natural, large, barren sandbars are present in unchannelized segments of the Missouri after rare, high-magnitude dam releases such as 1997, 2011, and 2019, but these sandbars gradually erode during normal dam operations (Catlin et al 2019, Sweeney et al 2019. Dredging has been used to construct sandbar habitats during long periods without highmagnitude dam releases (Sherfy et al 2012, Lott et al 2013.…”

“…Physical and hydrologic metrics important to tern nesting site selection and success have been widely documented, mainly within individual river reaches (Schwalbach 1988, Smith and Renken 1991, Kirsch 1996, Leslie et al 2000, Dugger et al 2002, Jorgensen et al 2012, Farnsworth et al 2018, Catlin et al 2019. Using previous work as a basis, we selected six a priori metrics to describe first-order tern nesting habitat availability and hydrologic conditions during the nesting season.…”

“…Three a priori metrics were used to quantify nesting habitat availability: (1) latitude in decimal degrees (L dd ), a general term to account for number of core nesting reaches in the migration direction; (2) Parker (1976) channel stability criteria (ε*), a physically based, dimensionless predictor of tendency of a river channel to be single thread or multiple thread (braided); and (3) reach-average active channel width (hWi) in meters, which has been shown to be positively related to tern nesting reach selection (Elliott et al 2009, Jorgensen et al 2012, Farnsworth et al 2018, Catlin et al 2019. hWi also serves as a gross measure of distance from riparian galleries and predators (Lott et al 2013, Catlin et al 2019. Increases in ε* indicate increasing tendency for a channel to deposit a central bar causing flow to split into more than one channel (i.e., braid), and ε* is thus expected to be positively related to tern nesting reach selection.…”