title: The importance of incorporating functional habitats into conservation planning for highly mobile species in dynamic systems.
abstract: The distribution of mobile species in dynamic systems can vary greatly over time and space. Estimating their population size and geographic range can be problematic and affect the accuracy of conservation assessments. Scarce data on mobile species and the resources they need can also limit the type of analytical approaches available to derive such estimates. We quantified change in availability and use of key ecological resources required for breeding for a critically endangered nomadic habitat specialist, the Swift Parrot (Lathamus discolor). We compared estimates of occupied habitat derived from dynamic presence-background (i.e., presence-only data) climatic models with estimates derived from dynamic occupancy models that included a direct measure of food availability. We then compared estimates that incorporate fine-resolution spatial data on the availability of key ecological resources (i.e., functional habitats) with more common approaches that focus on broader climatic suitability or vegetation cover (due to the absence of fine-resolution data). The occupancy models produced significantly (P < 0.001) smaller (up to an order of magnitude) and more spatially discrete estimates of the total occupied area than climate-based models. The spatial location and extent of the total area occupied with the occupancy models was highly variable between years (131 and 1498 km2). Estimates accounting for the area of functional habitats were significantly smaller (2-58% [SD 16]) than estimates based only on the total area occupied. An increase or decrease in the area of one functional habitat (foraging or nesting) did not necessarily correspond to an increase or decrease in the other. Thus, an increase in the extent of occupied area may not equate to improved habitat quality or function. We argue these patterns are typical for mobile resource specialists but often go unnoticed because of limited data over relevant spatial and temporal scales and lack of spatial data on the availability of key resources. Understanding changes in the relative availability of functional habitats is crucial to informing conservation planning and accurately assessing extinction risk for mobile resource specialists.
authors.affiliation: Fenner School of Environment and Society, Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Webb
authors.affiliation: Fenner School of Environment and Society, Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Aleks
authors.initials: A
authors.lastname: Terauds
authors.affiliation: Fenner School of Environment and Society, Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Ayesha
authors.initials: A
authors.lastname: Tulloch
authors.affiliation: Department of Zoology, University of Tasmania, Sandy Bay, Tasmania, 7005, Australia.
authors.forename: Phil
authors.initials: P
authors.lastname: Bell
authors.affiliation: Fenner School of Environment and Society, Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Dejan
authors.initials: D
authors.lastname: Stojanovic
authors.affiliation: Fenner School of Environment and Society, Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Heinsohn
mesh_terms: D025041:Animal Migration; D000818:Animals; D003247:Conservation of Natural Resources; D004463:Ecology; D017753:Ecosystem; D010311:Parrots
keywords: Lathamus discolor; disponibilidad de recursos dinámicos; dynamic resource availability; especialista de hábitat; especies amenazadas; explotador de fragmento rico; habitat specialist, Lathamus discolor; migración; migration; modelo de distribución de especies; rich patch exploiter; species-distribution modeling; threatened species