The package “adehabitat” for the R software: A tool for the analysis of space and habitat use by animals

Reintroductions are attempts to return species to parts of their historical ranges where they were extirpated, and might involve release of either captive-bred or wild-caught individuals. The poor success rate of reintroductions worldwide has led to frequent calls for greater monitoring, and since 1990 there has been an exponential increase in the number of peer-reviewed publications related to reintroduction. However, these publications have largely been descriptive accounts or have addressed questions retrospectively based on the available data. Here, we advocate a more strategic approach where research and monitoring targets questions that are identified a priori. We propose ten key questions for reintroduction biology, with different questions focusing at the population, metapopulation and ecosystem level. We explain the conceptual framework behind each question, provide suggestions for the best methods to address them, and identify links with the related disciplines of restoration ecology and invasion biology. We conclude by showing how the framework of questions can be used to encourage a more integrated approach to reintroduction biology.

/pdf/directions-in-reintroduction-biology-34yc9kov6l.pdf

Directions in reintroduction biology

The study of habitat use and selection in birds has a long tradition (Grinnell 1917, Kendeigh 1945, Svardson 1949, Hild6n 1965; Block and Brennan 1993). Early habitat-selection theory was characterized by correlative models of habitat characteristics and species abundance (MacArthur and Pianka 1966, Verner et al. 1986, Rosenzweig 1991), which subsequently evolved into models that involved density dependence: the "ideal-free distribution" and "ideal-despotic distribution" models (Fretwell and Lucas 1970, Fretwell 1972). More recently, habitat-selection studies have shown that many factors, such as landscape structure, can influence exactly how "ideal" and "free" animals are while moving through a landscape and selecting habitats (Karr and Freemark 1983, Pulliam and Danielson 1991, Petit and Petit 1996). Habitat-selection studies have recently assumed a new urgency, partially as a result of the importance of incorporating both habitat and demographic information into conservation planning (Caughley 1994). Nevertheless, ornithologists tend to be inconsistent in their conceptual framework and terminology with regard to (1) what constitutes habitat use versus selection, (2) the behavioral and evolutionary context of their findings, and (3) the order or scale of their study, from microhabitat to geographic range (Johnson 1980, Orians and Wittenberger 1991). The purpose of this review is to address those concerns through a survey of recent literature and highlight areas where improvements or advances can be made in avian habitat ecology. Three Areas of Concern.-Definitions.-The semantic and empirical distinctions between the terms habitat use and habitat selection are often unclear (Hall et al. 1997). Habitat refers to a distinctive set of physical environmental factors that a species uses for its survival and reproduction (Block and Brennan 1993). Habitat use refers to the way in which an individual or species uses habitats to meet its life history needs (Block and Brennan 1993). The study of habitat-use patterns describes the actual distribution of individuals across habitat types (Hutto 1985). Habitat selection refers to a hierarchical process of behavioral re-

/pdf/habitat-selection-studies-in-avian-ecology-a-critical-review-mochccjczw.pdf

Habitat Selection Studies in Avian Ecology: A Critical Review

Understanding habitat quality for birds is crucial for ecologists and managers, but few papers have explored the advantages and disadvantages of different ways to measure it. In this review I clarify terminology and distinguish habitat quality from related terms, differentiate habitat quality at the levels of individual birds and populations, and describe different field methods for measuring habitat quality. As much as feasible, biologists concerned with habitat quality should emphasize demographic variables while recognizing that reproduction, survival, and abundance may not all be positively correlated. The distribution of birds can also reveal habitat quality (e.g., through patterns of habitat selection), but researchers should first investigate how closely their subjects follow ideal distributions because numerous ecological factors can lead birds to select poor and avoid rich habitats. Measures of body condition can provide convenient measures of habitat quality, but to be useful they must be a consequence, rather than a cause, of habitat selection. Habitat ecologists should use caution before relying on shortcuts from more labor-intensive demographic work. To increase the reliability of our habitat quality measurements, we should work to develop new methods to assess critical assumptions of nondemographic indicators, such as whether birds follow ideal distributions under natural conditions and whether spatial variation in body condition manifests in differential fitness.

Measuring habitat quality: a review

Revisiting the concept of payments for environmental services

We compared the uses and definitions of habitat-related terms in 50 articles from 1980 to 1994 to operational definitions we derived from the literature. Only 9 (18%) of the arti- cles we reviewed defined and used habitat-related terms consistently and according to our definitions of the terms. Forty-seven articles used the term "habitat;" however, it was only defined and used consistent with our definition in 5 articles (11 %) and was confused with vegetation association or defined incompletely in 42 papers (89%). "Habitat type" was the term most commonly used incorrectly; 1 6 of 1 7 times (94%) it was used to indi- cate vegetation association, but habitat and vegetation association are not synonymous. Authors did not provide definitions for habitat use, selection, preference, or availability 23 of 28 times (82%). We concluded that habitat terminology was used vaguely in 82% of the articles we reviewed. This distorts our communication with scientists in other dis- ciplines and alienates the public because we give ambiguous, indefinite, and unstandard- ized answers to ecological questions in public and legal situations. Scientists should de- fine and use habitat terminology operationally, so that the concepts are measurable and accurate. We must take the challenge to standardize terminology seriously, so that we can make meaningful statements to advance science.

/pdf/the-habitat-concept-and-a-plea-for-standard-terminology-7flom2tlk6.pdf

The habitat concept and a plea for standard terminology

The elegant trogon (Trogon elegans) is a rare Neotropical migrant bird that occurs in southeasteri Arizona, where very little is known about this species in regards to potential threats to it, or habitat resources used by it. Consequently, we studied habitat selection by the elegant trogon at 4 spatial scales (mountain range canyon, home range, nest site) in southeastern Arizona to determine what resources constituted high-quality habitat (i.e., areas related to successful breeding and persistence of elegant trogons). At the broadest scales, elegant trogons were found in 4 mountain ranges. in canyons where there were sycamore trees (Platanus wrightu) in riparian areas. and mesquite (Prosopis spp.) in upland areas. Within home ranges, radiotagged elegant trogons used both riparian and upland areas, and successfully breeding elegant trogons used areas with dense understory vegetation. Nest sites were primarily located in sycamore trees and oaks (Quercus spp.) in riparian areas. Across all scales, elegant trogons were associated with variables describing sycamores. oaks, and pines (Pinus spp.). which indicated the importance of these trees as resources. We suggest management of elegant trogons in Arizona will require consideration of whole watersheds because elegant trogons use both riparian and upland zones, and management should include maintenance of high water tables in canyons to promote growth and recruitment of sycamore trees.

Multiscaled habitat selection by elegant trogons in southeastern Arizona

AnsTaAcr. -Sharp-shinned (Accipiter striatus), Cooper’s (A. cooperil], and Red-tailed (Buteo jamaicensis) hawks, and the total species (19) occurring in the Marin Headlands, Marin County, California, were quantified in relation to seven weather variables. Peak counts of raptors occurred in mid- to late September, with counts largely composed of immature hawks. More adult hawks were counted in mid- to late October. Adult and immature Sharpshinned and Cooper’s hawk counts were correlated with days before and after cold fronts, increasing temperature, barometric pressure, wind speed, and decreasing fog cover. Numbers of adult and immature Red-tailed Hawks were correlated negatively with fog and days before cold fronts and positively with temperature and barometric pressure. Cold front presence or absence did not affect Red-tailed Hawk numbers in 1986-1988. Fewer accipiters and Red-tailed Hawks were counted with south winds (headwinds) blowing, and in 1988 more adult birds were counted with north winds (tailwinds). Increasing temperatures, decreasing fog, and an absence of headwinds were correlated the most with counts of all species in the Headlands; cold front presence or absence had no significant influence on numbers in 19861988. A decreasing number of days before and after cold fronts was also generally associated with counts. Received 27 Sept. 1991, accepted IO Feb. 1992.

/pdf/the-influence-of-weather-on-hawk-movements-in-coastal-3yvltgdc7c.pdf

The Influence of Weather on Hawk Movements in Coastal Northern California

We determined intra- and interspecific patterns of habitat selection of mice living in an environment with a simple, but extremely variable resource base: the pinyon (Pinus mono- phylla)-juniper (Juniperus monosperma) woodland of the western Great Basin. Although numbers of deer mice (Peromyscus maniculatus) and pinyon mice (P truei) showed similar responses to varia- tions in resource abundance, the timing and age-related composition of this response in deer mice differed markedly from that in pinyon mice. Pinyon mice were resident on our study grids, but deer mice migrated onto the grids in response to a heavy pinyon cone crop. There were more significant correlations in intraspecific (sex-age) abundance in low cone years than in high cone years, and there was a moderate negative correlation between subadult and adult female pinyon mice during high cone years. There was an overall pattern for both Peromyscus species of fewer and weaker correlations between abundances and habitat characteristics during low cone years. During high cone years both fall and winter breeding activity was evident, and pinyon mice showed a three-fold higher rate of winter breeding than deer mice. All age classes of pinyon mice and deer mice showed a trend of higher between-season residency during low cone years. We conclude that different models of habitat selection operate dependent on the sex-age segment of the pop- ulation, season, and quantity and quality of the resource base. RESUMEN-Evaluamos c6mo la estructura de poblaciones de ratones responde a cambios natur- ales en los recursos y abundancia de especies co-habitantes en largos periodos. Nos planteamos esta tarea determinando los patrones de selecci6n de habitat intra e interespecificos de los ratones viviendo en un ambiente con recursos simples pero extremadamente variables de pifion, Pinus monophylla, Juniperus monosperma, en la arboleda del Western Great Basin. Aunque numerosos ratones de venados (Peromyscus maniculatus) y ratones de pifion (P truei) mostraron respuestas similares a las variaciones en la abundancia de los recursos a travos de todo el estudio, la selecci6n del momento oportuno y composici6n por edades de esta respuesta en ratones de venado difiere marcadamente de aquella en ratones de pifion. Los P truei fueron residentes en nuestras ;ireas de estudio pero los R maniculatus migraron hacia estas 'areas en respuesta a la gran cosecha de conos de pifion. El patr6n general fue uno de neutralidad para correlaciones de abundancia intraespecificas (sexo-edad) en ya sea afios de poca o mucha abundancia de conos, aunque hubo correlaciones mis significativas en afios de poca abundancia de conos, y hubo una correlaci6n negativa moderada entre hembras de P. truei subadultas y adultas durante los afios de mucha abundancia de conos. Hubo pocas correlaciones significativas interespecificas, pero los P truei y P maniculatus tendieron a relacionarse negativamente durante los anos de mucha y poca abun- dancia de conos. Hubo un patron general para ambas especies de Peromyscus de pocas y d6biles correlaciones entre abundancia y caracteristicas del htbitat en afios de pocos conos. En afios con muchos conos hubo reproducci6n en otofio e invierno y los P truei mostraron una tasa de re- producci6n en invierno tres veces la reproducci6n la de P maniculatus. Todas las categorias de edades de los R truei y P maniculatus mostraron una tendencia de mayor residencia entre esta- ciones en afios de pocos conos, que en afios de muchos conos. Concluimos que diferentes modelos de selecci6n de hibitat operan de una manera dinamica, dependiendo de la edad y sexo de la poblaci6n, estaci6n del afio y cantidad y calidad de los recursos. En este estudio el modelo ideal de selecci6n libre es la condici6n de sobre obtenci6n, con comportamiento desp6tico entre in- dividuos durante picos en la disponibilidad de recursos.

Responses of mice to fluctuating habitat quality i. patterns from a long-term observational study

This chapter reviews studies on songbird ecology conducted in Arizona, New Mexico, and Colorado; studies from outside this region are mentioned when they bear direct relevance to our primary region. The studies were conducted in sites where ponderosa pine occurred at least in equal coverage with other trees. We also include studies conducted in pine-oak (pine predominant) or oak-pine (oak predominant) woodlands of southeastern Arizona and Southwestern New Mexico. Our review begins with population studies, including research on distribution, abundance, and trends in population numbers. We then discuss the various roles of birds in the ponderosa pine forest. Next we cover the multifaceted topic of avian natural history and habitat preferences, including use of vegetation and special habitat features, nest predation, foraging habits, and migration habits. We also review the prioritization systems for identifying species of special research and management concern.

https://www.fs.fed.us/rm/pubs_rm/rm_gtr292/rm_gtr292_069_088.pdf

Linnea S. Hall

Papers

The habitat concept and a plea for standard terminology

Multiscaled habitat selection by elegant trogons in southeastern Arizona

The Influence of Weather on Hawk Movements in Coastal Northern California

Responses of mice to fluctuating habitat quality i. patterns from a long-term observational study

Songbird status and roles