Book

Nomadic Desert Birds

January 2004

DOI:10.1007/978-3-662-08984-2

ISBN: 978-3-642-07325-0

Authors:

W. R. J. Dean

Introduction

Chapter

Jan 2004
Nomadic Desert Birds

There are two basic strategies for coping with life in the desert: (1) to be resident and sedentary and by behavioural or physiological tactics able to withstand extremes of heat and cold, lack of water and fluctuations in the availability of food and plant cover, or (2) to be a migrant, and to opportunistically or seasonally move to where these resources are available. For at least one group of animals, the avifauna, both strategies have their advantages and disadvantages (Andersson 1980).

Migrations and Movements of Desert Birds

Chapter

Jan 2004
Nomadic Desert Birds
pp.17-36

The mobility of birds is a key to their survival in desert environments (Evenari 1985; Brown 1986; Wiens 1991). Indeed, mobility is the key for survival of many organisms in arid ecosystems, including humans (CloudsleyThompson 1977; Smith 1992; Seely 1994) and other large mammals such as Springbok Antidorcas marsupialis (Skinner 1993), Blue Wildebeest (Connochaetes taurinus), Burchell’s Zebra (Equus burchelli) (Sinclair 1984) and desert-dwelling African Elephants Loxodonta africana (Viljoen and Bothma 1990) in Africa. Some desert mammals, however, are restricted to fairly small home-ranges in arid ecosystems because of their need for water.

The Nomadic Avifauna

Chapter

Jan 2004
Nomadic Desert Birds
pp.37-80

Hyper-arid, arid and semi-arid ecosystems are characterised by low and unpredictable annual rainfall (Noy-Meir 1973), and by marked variability of all communities in time and space (Polis 1991). Resource peaks are unpredictable in time and space, and unpredictable in quality and quantity. Rainfall events, promoting local pulses in primary production, are often highly localised so that patches of vegetation and invertebrate populations at different phenological stages are scattered across the landscape. Patches may range from a few square centimetres to several square kilometres in area (Polis 1991) and maybe scattered over the landscape at distances from a few metres to many kilometres apart. The ability to rapidly find and exploit such patches is critical for animals living in arid ecosystems and the ability to move fast and far is obviously an advantage.

Habitats and Densities of Nomadic Birds

Chapter

Jan 2004
Nomadic Desert Birds
pp.81-100

Some nomadic bird species are confined to particular arid zones, whereas other species are not restricted to arid ecosystems but occur widely in other grassland and shrubland ecosystems. This raises the question of whether the birds are seeking out particular habitats, or particular foods, or are they adaptable enough to cope with a range of habitat and climatic conditions but not adaptable enough to cope with drought and diminishing resources as the resident species do. A large proportion of species of birds that are nomadic over large geographical areas are granivores, or omnivores that include seeds and insects in their diet (Maclean 1974; Davies 1984). Nectarivores and frugivores in arid ecosystems are locally nomadic, tracking patches of flowering or fruiting plants, although some nectarivores in Australia are nomadic over wider areas (Rowley 1974).

Food and Foraging

Chapter

Jan 2004
Nomadic Desert Birds
pp.101-122

Nomadic birds track resources that are, in the general sense, nomadic in time and space. Ephemeral plants in desert ecosystems that emerge, grow fast and produce large quantities of seeds after irregular rainfall events are, in effect, nomads in time. So are other potential foods, including outbreaks of rodents (Wilson 1970; Hollands 1979; Windberg 1998; Lima and Jaksic 1999; Lima et al. 1999; Perrin and Boyer 2000), breeding colonies of Wattled Starlings Creaophora cinerea (Liversidge 1961), Red-billed Queleas Quelea quelea (Ward 1965), stick insects (Phasmatidae) (Readshaw 1965), dragonflies (Odonata, Anisoptera) (Rudolph and Fisher 1993),noctuid moths, grasshoppers and locusts (Dingle 1996). Although there is some predictability in the movements of Red-billed Queleas, breeding colonies are seldom in the same place twice. The colonies provide food for larger nomadic birds such as Tawny Eagles Aquila rapax (Biggs 2001) and Lesser Spotted Eagles A. pomarina (Pienaar 1969; Kemp 2001).

Reproduction and Moult

Chapter

Jan 2004
Nomadic Desert Birds
pp.123-143

There are many constraints on reproduction for birds that are not resident or that migrate between fixed areas. Nomadic birds, often dependent on fairly short-lived resources, need to be adapted to being able to fairly rapidly find nest sites, build nests, lay eggs, raise young and move on together with the young once the food begins to run out. Elaborate, prolonged courtship displays can use up valuable time. Nevertheless, courtship displays in one family of birds in which there is a high proportion of nomads (the Alaudidae) vary among the nomadic species from intricate aerial manouvres with complicated songs to perch displays with monotonous songs, to quite simple ground displays with simple calls. Pre-breeding displays in Stark’s Lark Eremalauda starki and Grey-backed Sparrowlark Eremopterix verticalis may be quite synchronized, with hundreds of males calling and performing simultaneous aerial displays (Maclean 1970a, b; Willoughby 1971).

The Conservation of Nomadic Desert Birds

Chapter

Jan 2004
Nomadic Desert Birds
pp.145-147

Nomadic birds appear to be generally abundant wherever they occur. But are they? While it is true that none of the nomadic bird species in the world are classified as “threatened” or “endangered” in any of the Red Data books (Collar et al. 1994), what do we really know about population sizes, reproductive rates and survival of nomadic species? For almost all nomadic species, breeding success is low and variable from year to year (e.g. Maclean 1970b), predation pressure on adults and young is high, and breeding opportunities are intermittent in space and time. The extreme is shown by the Banded Stilt Cladorhynchus leucocephalus in central Australia, where breeding takes place at intervals of some years, in colonies numbering several thousands of birds (Robinson and Minton 1989). Although a limited amount of information on reproductive success can be collected for most species of nomadic birds, information on survival is largely unknown, and threats to the continued existence of species in certain areas have to be inferred from land use and the pressure on the environment. Although Reid and Fleming (1992, 1994) have suggested that nomadic passerines are less at risk than sedentary passerines in arid Australia, there are nevertheless risks for nomads.

The brown locust refocussed -Knowns, unknowns and the relevance of Locustana pardalina (Walker) to Karoo ecosystems and rangeland management

Article

Jun 2023
J ARID ENVIRON

Populations of brown locusts Locustana pardalina (Walk.) (Orthoptera, Acididae, Oedipodinae) alternate between resident solitaria grasshoppers in the Karoo via a transiens phase to nomadic gregaria locusts that periodically swarm across and beyond the Karoo. Concerns about crop damage led to this species being declared a pest in 1911 to be controlled with insecticides. Despite over 225 years of records of brown locust outbreak events and a considerable body of research during the early to mid-20th century, research impetus waned while outbreak events, as well as efforts at, and financial and ecological costs of chemical control, have steadily escalated. This review highlights particularly insightful field observations made by scientists between the 1920s and 1960s, which have yet to be followed up with further research. We revivify knowledge of brown locust solitaria ecology, including their diet, mainly consisting of the short grass, Enneapogon desvauxii, the cumulative build-up of egg banks with quiescent embryos, and how five to seven successive generations build up densities until crowding of nymphs brings about incipient outbreaks of gregaria locusts, which can aggregate into large swarms that depart to remote locations. Surprisingly, no quantitative records exist of the potential negative impacts at large scales of brown locusts on rangeland grazing or crop yields, nor have their potentially important roles for Karoo ecosystem functioning been well-documented. Although the quality of rangeland management affects the dynamics of outbreak centres, this recognition has not been followed up with experiments and detailed observations to make definite recommendations on farming practices. We suggest several avenues of research that build on the existing knowledge with modern techniques and fill the most important knowledge gaps to improve managing brown locust populations sustainably.

Landscape cover type, not social dominance, is associated with the winter movement patterns of Snowy Owls in temperate areas

Article

Full-text available

Mar 2021

Migrating animals occur along a continuum from species that spend the nonbreeding season at a fixed location to species that are nomadic during the nonbreeding season, essentially continuously moving. Such variation is likely driven by the economics of territoriality or heterogeneity in the environment. The Snowy Owl (Bubo scandiacus) is known for its complex seasonal movements, and thus an excellent model to test these ideas, as many individuals travel unpredictably along irregular routes during both the breeding and nonbreeding seasons. Two possible explanations for this large variation in the propensity to move are (1) dominance hierarchies in which dominant individuals (adult females in this case) monopolize some key, consistent resources, and move less than subdominants; and (2) habitat heterogeneity in which individuals foraging in rich and less heterogenic environments are less mobile. We analyzed fine-scale telemetry data (global positioning system [GPS]/global system for mobile communication [GSM]) from 50 Snowy Owls tagged in eastern and central North America from 2013 to 2019, comparing space use during the winter period according to sex and age, and to land cover attributes. We used variograms to classify individuals as nomadic (58%) or range-resident (42%), and found that nomadic owls had ten times larger wintering areas than range-resident owls. The frequency of nomadism was similar in socially-dominant adult females, immatures, and males. However, nomadism increased from west to east, and north to south, and was positively associated with the use of water and negatively associated with croplands. We conclude that many individual Snowy Owls in Eastern North America are nomadic during the nonbreeding season and that movement patterns during this time are driven primarily by extrinsic factors, specifically heterogeneity in habitat and prey availability, as opposed to intrinsic factors associated with spacing behavior, such as age and sex.

New records of 45 bird species in the desert margins area of the North-West Province, South Africa

Article

Full-text available

Nov 2018
Koedoe

2006. New records of 45 bird species in the desert margins area of the NorthWest Province, South Africa. Koedoe 49(1): 91-98. Pretoria. ISSN 0075-6458. New records and possible range extensions are reported on 45 bird species (ca 25% of the 167 species recorded during surveys) in the Bophirima district of the NorthWest Province, South Africa. The findings were compared with data in The Atlas of Southern African Birds. The main reasons for these new records may be ascribed to the low number of visits during the atlas project, higher precipitation during the time of our observations versus that of the atlas project, and possibly an increased suitability of the area for some bird species due to human habitation. These new records also provide additional information that may be useful in conservation planning, especially in arid areas. Heuningvlei Pan in particular, should be considered for additional conservation measures .

Movement ecology of nomadic arid zone waterfowl

Thesis

Jun 2014

John McEvoy

This thesis provides insights into the spatial and temporal patterns of movement in nomadic waterfowl, the response of birds to rapid environmental change, behavioural flexibility of avian movements and the ability of birds to locate seemingly unpredictable water bodies in vast arid landscapes.

Avian movements in a modern world: cognitive challenges

Article

Full-text available

Jan 2017
ANIM COGN

Claudia Mettke-Hofmann

Different movement patterns have evolved as a response to predictable and unpredictable variation in the environment with migration being an adaptation to predictable environments, nomadism to unpredictable environments and partial migration to a mixture of predictable and unpredictable conditions. Along different movement patterns, different cognitive abilities have evolved which are reviewed and discussed in relation to an organism’s ability to respond to largely unpredictable environmental change due to climate and human-induced change, and linked to population trends. In brief, migrants have a combination of reliance on memory, low propensity to explore and high avoidance of environmental change that in combination with overall small brain sizes results in low flexibility to respond to unpredictable environmental change. In line with this, many migrants have negative population trends. In contrast, while nomads may use their memory to find suitable habitats, they can counteract negative effects of finding such habitats disturbed by large-scale exploratory movements and paying attention to environmental cues. They are also little avoidant of environmental change. Population trends are largely stable or increasing indicating their ability to cope with climate and human-induced change. Cognitive abilities in partial migrants are little investigated, but indicate attention to environmental cues coupled with high exploratory tendencies that allow them a flexible response to unpredictable environmental change. Indeed, their population trends are mainly stable or increasing. In conclusion, cognitive abilities have evolved in conjunction with different movement patterns and affect an organism’s ability to adapt to rapidly human-induced changes in the environment. Electronic supplementary material The online version of this article (doi:10.1007/s10071-016-1006-1) contains supplementary material, which is available to authorized users.

Revealing unexpected uses of space by wintering Aquila pomarina: How does satellite telemetry identify behaviour at different scales?

Article

Full-text available

Nov 2015

Little is understood about the dispersion and movements of Palaearctic migrant raptors while wintering in southern Africa. The high temporal and spatial resolution of GPS telemetry data provided the opportunity to describe how space is used by one such migratory raptor in its wintering range, the lesser spotted eagle Aquila pomarina. Kernel density estimation was used to map the distribution of three individuals at various spatial scales. In addition to their extremely large overall wintering range (up to 112 000 km2), three finer levels of spatial concentration were identified: favoured activity zones where the birds spent much of the winter, smaller core areas to which the birds returned each year, and tiny intensive foraging clusters. Philopatry was demonstrated by one bird which revisited core areas over eight wintering seasons. The same core areas, particularly the Waterberg, Grootfontein (Namibia) and the eastern and western sides of the Okavango Delta (Botswana), were visited by two other eagles in 2012/2013, although not simultaneously. Such results potentially provide important information on areas where conservation activities might be focused to mitigate human degradation of habitat.

Locust Times - monitoring populations and outbreak controls in relation to Karoo natural capital

Article

Full-text available

May 2015

Joh R. Henschel

Three decades ago a locust conference in Kimberley deliberated on the Brown Locust Locustana pardalina (Walker), its biology, feeding ecology, population dynamics, outbreak extent and frequency, swarm movements and artificial control of outbreaks. The current paper evaluates recommendations made at this conference. In contrast to the high levels of effort and funding allocated for over a century to the control of locust swarms by means of insecticides, relatively little has been spent on research of the Brown Locust, not even to verify and characterise the actual problem. Methods of locust control have improved and environmental impacts of current applications are somewhat reduced. A critical, comprehensive cost-benefit analysis, necessary to evaluate whether costly control measures and continuous interventions are warranted, has still not been conducted. Many other knowledge gaps remain, such as the ecological significance of locusts as one of the remaining swarming phenomena of the Karoo. Swarms of locusts feed here, defecate there, and die elsewhere, while numerous predators track locust abundance cycles and movements, altogether forming intricate patterns over time and space of dynamic food webs and nutrient recycling across the Karoo and beyond. Past records of Brown Locust population irruptions and crashes in the Karoo extend over 200 years. Suggestions are made on how longterm monitoring could be continued and broadened to encompass knowledge gaps. Brown Locusts are potentially useful indicators of ecosystem integrity and climate change, a potential that should be tested.

Wintering - J Avian Biol 2015

Data

Full-text available

Jul 2015

Geographic range size and extinction risk assessment in nomadic species

Article

Full-text available

Jan 2015
CONSERV BIOL

Geographic range size is often conceptualized as a fixed attribute of a species and treated as such for the purposes of quantification of extinction risk; species occupying smaller geographic ranges are assumed to have a higher risk of extinction, all else being equal. However many species are mobile, and their movements range from relatively predictable to-and-fro migrations to complex irregular movements shown by nomadic species. These movements can lead to substantial temporary expansion and contraction of geographic ranges, potentially to levels which may pose an extinction risk. By linking occurrence data with environmental conditions at the time of observations of nomadic species, we modeled the dynamic distributions of 43 arid-zone nomadic bird species across the Australian continent for each month over 11 years and calculated minimum range size and extent of fluctuation in geographic range size from these models. There was enormous variability in predicted spatial distribution over time; 10 species varied in estimated geographic range size by more than an order of magnitude, and 2 species varied by >2 orders of magnitude. During times of poor environmental conditions, several species not currently classified as globally threatened contracted their ranges to very small areas, despite their normally large geographic range size. This finding raises questions about the adequacy of conventional assessments of extinction risk based on static geographic range size (e.g., IUCN Red Listing). Climate change is predicted to affect the pattern of resource fluctuations across much of the southern hemisphere, where nomadism is the dominant form of animal movement, so it is critical we begin to understand the consequences of this for accurate threat assessment of nomadic species. Our approach provides a tool for discovering spatial dynamics in highly mobile species and can be used to unlock valuable information for improved extinction risk assessment and conservation planning. © 2014 The Authors. Conservation Biology published by Wiley Periodicals, Inc., on behalf of the Society for Conservation Biology.

A telemetry study shows that an endangered nocturnal avian species roosts in extremely dry habitats to avoid predation

Article

Full-text available

Jul 2023

Describing animal space use is essential for understanding their ecological needs and for planning effective conservation schemes. Notably, certain biomes and life histories are understudied due to methodological challenges in tracking animals in their natural habitats. Specifically, both arid environments and nocturnal species are not sufficiently researched compared to diurnal species and to other biomes. This knowledge gap hinders our ability to properly prioritize habitats for species protection in areas undergoing human-related development. Here, we investigate the movement ecology of the Egyptian Nightjar (Caprimulgus aegyptius) in the arid Dead-sea region of Israel, the Palestinian Authority (the West Bank) and Jordan. This nocturnal insectivore is a cryptic desert-dweller and was considered locally extinct until it was rediscovered in 2016. For this work we tracked twelve individuals using GPS tags to determine how this resource-poor environment affects their home range, (predicting large areas), habitat use, and day-roost ecology. We found that the tracked Egyptian Nightjars had a much larger home range area than other Nightjar species, commuting nightly between foraging grounds and day-roosts. We found, as expected, intensive foraging activity at agricultural fields, where artificial irrigation likely supports higher resource (insect) density. Additionally, we found that individuals showed very high roosting site fidelity, often returning to the same specific site, located in extremely dry and exposed habitats, presumably for predator avoidance. This finding highlights the ecological value of these barren habitats that are often considered “lifeless” and therefore of lower priority for conservation. Consequently, our research demonstrates the importance of describing the space-use of nocturnal animals in arid habitats for conservation efforts.

Responses of Bird Communities to Habitat Structure along an Aridity Gradient in the Steppes North of the Sahara

Article

Full-text available

Jun 2023
Diversity

We explored the influence of habitat structure on bird density and species richness in the poorly known bird communities in the steppes of Eastern Morocco, along a 200 km long N–S gradient of increasing aridity. The birds were surveyed, and habitat structure was measured in 44 transects regularly distributed along the gradient and during the winter and spring seasons in two consecutive years. After applying a principal component analysis (PCA), five axes were identified, including one related to the latitude–altitude–soil-type gradient and another describing the development of herbaceous vegetation. Generalized linear models were used to explore the relations between bird density and species richness with PCA axes in each season, considering both the entire community and groups of granivorous, insectivorous, and mixed-diet species. More than 90% of the birds were year-round residents, with larks dominating the community in both seasons. We conclude that a distinct multifactorial response can be identified for each functional group of species. In the winter, the community is mainly affected by the structure of the habitat, while aridity (and its assumed relation to primary production) is less influential. In the spring, habitat structure continues to have the greatest explanatory power, but location along the aridity gradient becomes more relevant. These findings reveal the interaction of the negative effects of climatic and anthropogenic changes in the habitat available to these bird communities, with a greater impact expected on birds with diets that include seeds, as well as a general shift of optimal breeding conditions toward more northerly latitudes.

Henschel etal (2023) Richard Dean documenting Karoo complexity

Article

Jul 2023
J ARID ENVIRON

In August 2022, the renowned ecologist and ornithologist, Dr William Richard John Dean (Richard), passed away aged 82. He had served on the Editorial Board of the Journal of Arid Environments for 20 years until 2021. Richard’s penchant for writing, both scientific (294 journal articles and book chapters, 6 books) and popular science, contributed significantly to what is known about arid regions globally and to the Karoo, an area covering a third of South Africa and Namibia, in particular. His encyclopaedic knowledge was legendary, aptly remarked by Timm Hoffman (pers. comm.): “Richard was the best naturalist I have ever met. Many of his publications reflect his broad integration of different influences on the environment, whether by birds, ants, aardvarks, plants, soil or seeds.” Roy Siegfried (pers. comm.) added that Richard was more than an avid naturalist, as he had such an astute questioning mind, the mark of a great scientist. Indeed, Richard’s contributions to the ecology of arid environments are globally relevant. Here, we pay tribute to Richard Dean by expounding some of his significant scientific contributions to arid land ecology, some of which were developed in synergy with his wife, Sue Milton (Fig. 1), while recognising that he was also a leading ornithologist in his own right. We start with an overview of his professional development and then unfold a few examples of his notable insights into the Karoo and other drylands and what these mean for understanding arid lands in general, concluding with a synopsis of his outlook.

Patrones de movimiento de tres especies de aves granívoras en el desierto del Monte central, Argentina: diferencias dentro y entre especies [TRADUCCION AL ESPAÑOL DEL ARTICULO PUBLICADO EN: Emu, 2014, 114, 268–276_DOI:http://dx.doi.org/10.1071/MU13098]

Article

Full-text available

Nov 2022

El conocimiento de los movimientos de las poblaciones de paseriformes en el hemisferio sur es difícil de lograr, en parte debido a las diferencias en los movimientos entre y dentro de las especies y entre y dentro de las poblaciones. En América del Sur templada, las descripciones de los patrones de movimientos a menudo se basan en información de cambios locales en la abundancia y ocurrencia de especies y ha habido pocos estudios detallados de movimientos de poblaciones locales. Anillamos y monitoreamos individuos de tres especies de aves granívoras: el Pepitero Chico (Saltatricula multicolor), la Monterita de collar (Poospiza torquata) y el Chingolo (Zonotrichia capensis) en un sitio templado en el desierto del Monte central, Argentina, para evaluar las diferencias en el grado de sedentariosmo entre y dentro de las especies. Encontramos poblaciones residentes de las tres especies, cuyos juveniles mostraron poca fidelidad al sitio. También observamos una gran afluencia de Monteritas de collar y Chingolos durantela temporada no reproductiva. Confirmamos la migración parcial poblacional de dos subespecies de Chingolos (y, posiblemente, una tercera subespecie residente), y posiblemente también dentro de las Monteritas de collar. Las afluencias de individuos móviles durante la temporada no reproductiva pueden ser en respuesta a un clima impredecible y la consiguiente disponibilidad de recursos, como se ha encontrado en regiones áridas de Australia y África. Nuestros resultados proporcionan una base para una mejor comprensión de la evolución de los patrones demovimiento de las aves en las zonas templadas de América del Sur.

Seasonal nomadism and pre-breeding scouting forays of a Spotted Sandgrouse (Pterocles senegallus)

Article

Sep 2021

Movement rules determine nomadic species’ responses to resource supplementation and degradation

Article

Aug 2020

In environments that vary unpredictably, many animals are nomadic, moving in an irregular pattern that differs from year to year. Exploring the mechanisms of nomadic movement is needed to understand how animals survive in highly variable environments, and to predict behavioural and population responses to environmental change. We developed a network model to identify plausible mechanisms of nomadic animal movement by comparing the performance of multiple movement rules along a continuum from nomadism to residency. Using simulations and analytical results, we explored how different types of habitat modifications (that augment or decrease resource availability) might affect the abundance and movement rates of animals following each of these rules. Movement rules for which departure from patches depended on resource availability and/or competition performed almost equally well and better than residency or uninformed movement under most conditions, even though animals using each rule moved at substantially different rates. Habitat modifications that stabilized resources, either by resource supplementation or degradation, eroded the benefits of informed nomadic movements, particularly for movements based on resource availability alone. These results suggest that simple movement rules can explain nomadic animal movements and determine species’ responses to environmental change. In particular, landscape stabilization and supplementation might be useful strategies for promoting populations of resident animals, but would be less beneficial for managing highly mobile species, many of which are threatened by habitat disruption and changes in climate.

Beyond Migration: Causes and Consequences of Nomadic Animal Movements

Article

Mar 2019
TRENDS ECOL EVOL

Recent advances in animal tracking reveal that many species display irregular movements that do not fall into classical categories of movement patterns such as range residency or migration. Here, we develop a unifying framework that distinguishes these nomadic movements based on their patterns, drivers, and mechanisms. Though they occur in diverse taxa and geographic regions, nomadic movements are united by both their underlying environmental drivers, mainly environmental stochasticity, and the resulting irregular, far-ranging movement patterns. The framework further classifies types of nomadic movements, including full, seasonal, phase, irruptive, and partial nomadism. Nomadic movements can have unique effects on populations, communities, and ecosystems, most notably providing intermittent disturbances and novel introductions of propagules.

Incoporating dynamic distributions into spatial priortization

Article

Nov 2015

Aim Species' distributions are generally treated as static for the purposes of prioritization, but many species such as migrants and nomads have distributions that shift over time. Decisions about priority actions for such species must account for this temporal variation, making planning for their conservation a complex problem. Here, we explore how dynamic distributions can be incorporated into a spatial prioritization, and suggest approaches for prioritizing conservation action when knowledge of species' movements is uncertain. Location Australian rangelands, including the arid and semi‐arid zones of central Australia and adjoining monsoonal tropics, although methods are applicable for any dynamic biodiversity feature. Methods We used the decision‐support software marxan to explore the impact of temporal dynamics on spatial conservation planning for a suite of 42 highly mobile birds across the study region. We explored scenarios comparing a static representation of species' distributions with four methods of integrating temporal dynamics: (1) accounting for temporal variability in distribution across months and years, (2) considering only monthly variability in distribution, (3) considering only annual variability in distribution and (4) considering only minimal distributions during spatial bottlenecks, ignoring distributions at other times. Results Incorporating the temporal dynamics of species into spatial prioritization substantially changes the spatial pattern of conservation investment, increasing the overall area needed to be placed under conservation measures to achieve a specific target level of species protection. Targeting bottlenecks, locations critical to each species when its distribution is at a minimum, prioritizes a very different suite of sites to those chosen using the traditional approach of static distribution maps based on occurrences pooled across time. Main conclusions Our results highlight the need to consider dynamic movements in the conservation planning process to ensure that mobile species are adequately protected. A static approach to conservation planning may misdirect resources and lead to inadequate conservation for mobile species.

Itinerant lifestyle and congregation of lesser kestrels in West Africa

Article

Nov 2023
J AVIAN BIOL

Trans‐Saharan migrants often spend a large proportion of their annual cycle wintering in the Sahel. Advances in fieldwork and tracking technology have greatly enhanced our ability to study their ecology in these areas. Using GPS‐tracking we aimed to investigate the little known non‐breeding movements of the lesser kestrel Falco naumanni in sub‐Saharan Africa. We segment non‐breeding tracks (n = 79 tracks by 54 individuals) into staging events (131 ± 25 days per non‐breeding cycle), itinerant movements between staging sites (11 ± 10 days), and non‐directed exploratory movements (6 ± 5 days). We then describe timing and directionality of itinerant movements by male and female kestrels throughout the non‐breeding season. Regardless of sex, lesser kestrels spent on average 89% of the non‐breeding season staging at two (range = 1–4) sites in West Africa. At the end of September, kestrels arrived along a broad front throughout the northern Sahel. By December, however, they congregated into two distinct clusters in Senegal and along the Malian–Mauritanian border. The birds stayed for longer periods and showed greater daily activity in the latter areas, compared to their first and intermediate ones. Among 24 individuals tracked along multiple annual cycles, 20 individuals consistently used the Senegalese or Malian–Mauritanian cluster. The remaining four birds either used these clusters in the 2nd or 3rd year of tracking or alternated between them across different years. The eastward and westward itinerant movements of lesser kestrels during the non‐breeding season, coupled with their tendency to cluster geographically towards the end, differ from the southward movements of other insectivorous raptors in West Africa. While 31% of Spanish lesser kestrels converged in Senegal, where roosts of > 20 000 birds are known, 68% moved into the Malian‐Mauritanian border region where more groundwork is needed.

MIGRATION ECOLOGY AND HARVEST EXPOSURE RISK OF LESSER YELLOWLEGS

Thesis

Full-text available

May 2021

The Lesser Yellowlegs (Tringa flavipes) is a migratory shorebird species that has experienced a precipitous population decline. The factors governing this decline are complex and may correspond to habitat traits and migratory dynamics. Recent advancements in GPS telemetry have allowed for a precise description of migratory patterns to interpret the spatial and temporal distributions of migratory bird species compared to prior approaches that used band recoveries, surveys, and morphological measurements. Understanding the similarities and differences in distributions among and within disparate populations of birds is critical for identifying the potential exposure to threats that influence a species’ productivity and survival. Detailed distribution data provides the foundation for the development and implementation of targeted conservation applications for declining species, such as the Lesser Yellowlegs. In 2018, 2019, and 2020, project cooperators and I deployed 110 PinPoint GPS Argos satellite tags on adult Lesser Yellowlegs at six sites spanning the boreal biome of Alaska and Canada. The Lesser Yellowlegs is a Neotropical migrant shorebird that breeds in the boreal forest and spends the winter in Central and South America and the Caribbean. Upon summarizing the locations received, I found that geographically disparate populations followed different routes during autumn migration, but experienced weak migratory connectivity, or high population mixing, at wintering locations. Differentiation in migratory timing, distances, and strategies were also variable among sexes and breeding populations. Further, I described the primary stopover, staging, and wintering sites and determined that the Prairie Pothole region and the Gulf Coast region were the primary stopover sites during autumn and spring migration, whereas northeastern Argentina was the primary wintering area. Within each of those regions, the highest proportion of Lesser Yellowlegs detections were in wetland habitats. Lastly, I modeled the probability of Lesser Yellowlegs occurring within Caribbean and northeastern South American countries where shorebirds are harvested for sport and subsistence. I found that geographically disparate populations were differentially exposed to shorebird harvest. Populations originating from eastern Canada had the highest probability of occurrence and longest duration of stay within harvest zones from mid-August through October, while populations originating from Alaska had an exposure probability of nearly zero throughout the autumn. The Lesser Yellowlegs has experienced a precipitous population decline of ~63% since the 1970s. Within the next decade, it is predicted that an additional 50% of the current population size will be lost if science-driven conservation actions are not practiced. By using real-time location data to identify annual migration patterns and the probabilities of harvest exposure among disparate populations of Lesser Yellowlegs, my thesis provides the knowledge for tailoring conservation priorities and actions for specific geographic regions or subpopulations that are at high risk (e.g. populations originating in eastern Canada). Focusing conservation efforts to areas where scientifically rigorous analyses illustrate serious concern is an effective approach to ensure the perseverance of a steeply declining shorebird.

Spatial ecology and conservation management of the endangered sandhill dunnart, Sminthopsis psammophila

Thesis

Full-text available

Nov 2020

Jo Riley

We are experiencing a global biodiversity and climate crisis that is rapidly causing the extinction of species. Mammal species have been disproportionately affected; however, this trend is considerably worse in Australia. Since Australia’s occupation by Europeans, 34 mammal species have been declared extinct. Australian mammals in deserts are particularly at risk of extinction. Many arid zone mammals have specialised adaptations to their hostile, unpredictable ecosystems. For example, they use thermally insulative refuges, prefer habitats that reduce predation risk, or have large home ranges and broad diets to maximise energy intake. Understanding these adaptations is essential for informed conservation management. However, little ecological data is known for the sandhill dunnart, Sminthopsis psammophila, an endangered and charismatic marsupial that now remains within just a few natural refugial habitats in Australia’s southern deserts. To address conservation biology knowledge gaps, an integrated, evidence-based approach (i) quantified the diurnal and nocturnal ecology of S. psammophila in the Western Australian Great Victoria Desert (WAGVD), (ii) estimated the past, present and future distributions of S. psammophila throughout Australia, (iii) examined the key threats to S. psammophila - particularly wildfires and anthropogenic climate change - and (iv) proposed conservation management solutions for a) S. psammophila and b) sympatric arid zone species. Between 2015 and 2019, radio tracking and global positioning system (GPS) technologies examined the sheltering, foraging, dietary and habitat preferences of S. psammophila in the WAGVD. In contrast to its previously reported habitat preferences, S. psammophila preferred burrowing within long unburned (32+ years since a wildfire) spinifex (Triodia spp.) grassland habitats. Dense lower stratum swale, sand plain and dune slope habitats were preferred, whereas habitats lacking spinifex and open dune crest habitats were rarely used. Hence, wildfires were identified as a significant threat to the species. The sheltering preferences of S. psammophila agreed with the premise that small desert mammals often use shelters with thermal advantages and anti-predation benefits, such as burrows, Lepidobolus deserti hummocks and logs. Conversely, spinifex hummocks were not found to be insulative against extreme temperatures and were not preferred. The foraging adaptations of S. psammophila agreed with the premise that arid zone species often have large home ranges to exploit resource patches or islands. The 100 % home ranges of S. psammophila [mean: 70 ha; range: 6-274 ha; minimum convex polygon (MCP)] were influenced by sex and reproductive status. In addition, a Formicine-rich diet indicated that ants are an important dietary resource for S. psammophila. Species distribution models (SDMs) predicted the past, present, and future distributions of S. psammophila, evaluated the environmental parameters that determine the species’ distribution and identified habitats of high conservation value. The past model supported evidence that S. psammophila was widespread but has recently contracted to more climatically favourable areas of its geographic range. Ground-validation of the present model’s predictions discovered a population 150 km north of the species’ known range. Future models identified that climate change is a potential catastrophic threat for S. psammophila. By 2050, under Representative Concentration Pathway (RCP) 8.5 (our current pathway) there is a predicted 95 % reduction in suitable habitat for S. psammophila in the WAGVD. By 2070 (RCP 8.5), only the Eyre Peninsula population may remain viable and the continental distribution of S. psammophila may contract by up to 80 %. However, this contraction is predicted to be halved if global greenhouse gas emissions peak in 2040 then reduce (RCP 4.5). Due to specific habitat preferences for long unburned habitats, S. psammophila is further restricted within its climatically and geographically suitable range. As a semi-arid specialist, it is also vulnerable to drought-related population crashes. Hence, S. psammophila should remain listed as endangered at the state and federal level, and its status should be revised by the International Union for Conservation of Nature.

Avian mortality risk during heat waves will increase greatly in arid Australia during the 21st century

Article

Full-text available

Jun 2020

Intense heat waves are occurring more frequently, with concomitant increases in the risk of catastrophic avian mortality events via lethal dehydration or hyperthermia. We quantified the risks of lethal hyperthermia and dehydration for 10 Australian arid-zone avifauna species during the 21st century, by synthesizing thermal physiology data on evaporative water losses and heat tolerance limits. We evaluated risks of lethal hyperthermia or exceedance of dehydration tolerance limits in the absence of drinking during the hottest part of the day under recent climatic conditions, compared to those predicted for the end of this century across Australia. Increases in mortality risk via lethal dehydration and hyperthermia vary among the species modelled here but will generally increase greatly, particularly in smaller species (∼10-42 g) and those inhabiting the far western parts of the continent. By 2100 CE, zebra finches' potential exposure to acute lethal dehydration risk will reach ∼ 100 d y −1 in the far northwest of Australia and will exceed 20 d y −1 over > 50% of this species' current range. Risks of dehydration and hyperthermia will remain much lower for large non-passerines such as crested pigeons. Risks of lethal hyperthermia will also increase substantially for smaller species, particularly if they are forced to visit exposed water sources at very high air temperatures to avoid dehydration. An analysis of atlas data for zebra finches suggests that population declines associated with very hot conditions are already occurring in the hottest areas. Our findings suggest that the likelihood of persistence within current species ranges, and the potential for range shifts, will become increasingly constrained by temperature and access to drinking water. Our model adds to an increasing body of literature suggesting that arid environments globally will experience considerable losses of avifauna and biodiversity under unmitigated climate change scenarios.

Watson and Keren - Repeatability in

Article

Full-text available

Mar 2020
WILSON J ORNITHOL

James Watson

Understanding and predicting global change impacts on migratory birds

Thesis

Full-text available

Jan 2019

Merlin Schaefer

This is a publication-based dissertation comprising three original research stud-ies (one published, one submitted and one ready for submission; status March 2019). The dissertation introduces a generic computer model as a tool to investigate the behaviour and population dynamics of animals in cyclic environments. The model is further employed for analysing how migratory birds respond to various scenarios of altered food supply under global change. Here, ecological and evolutionary time-scales are considered, as well as the biological constraints and trade-offs the individual faces, which ultimately shape response dynamics at the population level. Further, the effect of fine-scale temporal patterns in re-source supply are studied, which is challenging to achieve experimentally. My findings predict population declines, altered behavioural timing and negative carry-over effects arising in migratory birds under global change. They thus stress the need for intensified research on how ecological mechanisms are affected by global change and for effective conservation measures for migratory birds. The open-source modelling software created for this dissertation can now be used for other taxa and related research questions. Overall, this thesis improves our mechanistic understanding of the impacts of global change on migratory birds as one prerequisite to comprehend ongoing global biodiversity loss. The research results are discussed in a broader ecological and scientific context in a concluding synthesis chapter.

The effect of general sense of perceived self-efficacy on internal and external locus of control among rural youths of Mantanani island

Chapter

Full-text available

Oct 2019

Getrude C Ah Gang

The present study showed that the general sense of perceived self-efficacy does not appear to favor one locus of control, but rather simultaneously contribute to both loci of control. This should be examined further. We hope that the findings from this study may help us to understand how the general sense of perceived self-efficacy contributes to both loci of control. In our hypotheses, we predicted that the general sense of perceived self-efficacy would contribute to both loci of control, and this was indeed what we found. This shows that although the participants perceived that they have the capabilities to cope with life events, and that these capabilities contribute to their beliefs that they can control their lives, they also believe that the other, external, locus of control, such as fate, luck and powerful others can affect their life events. In the future, it would be beneficial to examine how general perceived self-efficacy contributes to both loci of control in different situational factors, such as academia, personal relationships and work life.

Repeatability in migration of Ferruginous Hawks (Buteo regalis) and implications for nomadism

Article

Full-text available

Oct 2019

Nomadism in birds is characterized by inconsistent and unpredictable migrations to breeding or nonbreeding areas often related to changing prey conditions. The Ferruginous Hawk (Buteo regalis) has been described as nomadic in studies that documented fluctuations in breeding territory occupancy and synchronous changes in prey abundance. However, documentation of tracked individuals engaged in nomadic movements is lacking and is important for evaluating population status. Between 1999 and 2014 we studied repeatability in patterns of interannual range occupancy and migration of radio-tagged, breeding adult Ferruginous Hawks (n = 33). We computed repeatability coefficients to test individual fidelity to seasonal ranges and migration paths, and timing of migrations among range-wide populations over multiple years (range = 2–6 yr). Hawks exhibited dramatic seasonal differences in annual repeatability of individual movements. During the post-breeding period in late summer, repeatability coefficients for annual range occupancy and migration path fidelity were low (r = 0.37), only 50% of hawks showed range fidelity, and hawks occupied multiple ranges (x̄ = 1.5 ± 0.2 ranges/yr). In contrast, repeatability was moderate to high (r ≥ 0.65) in the breeding season and winter, 83% and 87% of hawks showed range fidelity to respective ranges, and hawks occupied an average of one range each season. All hawks returned to the same breeding region each year. Variation attributed to differences between individuals was significant for most migration characteristics, providing evidence for flexibility within the species for individuals to adapt to different situations and conditions, but with each individual tending to follow the same patterns over multiple years. Seasonal nomadism in Ferruginous Hawks was limited to the post-breeding period in late summer, and we found no evidence for systematic nomadism in spring migration of Ferruginous Hawks that would confound interpretation of breeding population trends. However, we recommend further telemetry studies to simultaneously document migration repeatability for this species prior to and during dramatic prey declines.

Ecology of the Grey Falcon Falco hypoleucos – current and required knowledge

Article

Sep 2019

Australia’s endemic Grey Falcon is an iconic but elusive bird of the arid interior. Whilst reviews of its ecology and status are more than 25 years old, new targeted studies include a population size estimate that is considerably lower (<1,000 individuals) than the one previously advanced (<5,000 individuals). According to this revised estimate, the Grey Falcon’s national conservation status should be considered to be ‘Vulnerable’, but the species is not declared threatened under Australian national legislation. A ‘threatened’ listing could, however, be expected if support for the lower population size estimate becomes available. A prerequisite for investigations aiming to test that estimate, and to determine what may threaten the future of this species, is a more comprehensive understanding of the species’ ecology. Our analysis of the relevant literature on the species’ ecology shows that the Grey Falcon is unique among its congeners in persisting exclusively in a hot arid/semi-arid environment, and in its strong dietary restriction. Further, young Grey Falcons may live in the close company of their parents up to a year after fledging, and this would be unique among raptors of that size if correct. Finally, the species’ environment is characterised by extreme, unpredictable climatic events, and understanding how these birds interact with these environmental features is key to assessing their possible responses to climate change.

Birds as Food: Anthropological and Cross-disciplinary Perspectives, Enfield, ICAF UK, 2018, ix + 328 p. [Ed. by Frédéric Duhart and Helen Macbeth] [ISBN 978-0-9500513-0-7]

Book

Full-text available

Feb 2018

Birds as Food: Anthropological and Cross Disciplinary Perspectives is a collection of essays by anthropologists and contributors from other disciplines. Traditions of using birds as food exist in almost all human societies past and present. Over a hundred different species around the world are mentioned in this volume. The contributions are supported with full colour illustrations of birds whether alive or in culinary preparations. Birds as Food: Anthropological and Cross-disciplinary Perspectives Ed. Frédéric Duhart and Helen Macbeth ICAF (UK) Enfield, United Kingdom 2018 ix + 328 p. Serie: ICAF Alimenta Populorum series, Volume I ISBN 978-0-9500513-0-7

Plumage development and moult in captive Black-bellied Sandgrouse Pterocles orientalis: age and sex variations

Article

Full-text available

Oct 2018

The sandgrouse, family Pteroclididae, are a group of birds adapted to open, arid habitats and powerful fliers but information on their plumage development and moult is scarce. In this study, the annual cycle of body plumage development, sequence and duration of primary flight feathers moult were investigated in Black-bellied Sandgrouse Pterocles orientalis, from hatching to the adult stage. Body plumage differed among juvenile, immature and subadult birds before their first breeding season. Yearling Black-bellied Sandgrouse showed three annual moults with only the pre-breeding one being complete. Juvenal body plumage was acquired shortly before the first attempts to fly at 5–6 weeks of age. The acquisition of definitive adult body plumage took place after the breeding season in late August, when birds were about 10–12 months old. The species typically replaced all primaries annually with a gradual descendent moult at a slow rate, taking 10–11 months for their completion, from December to September, including the breeding period. This study provides the first detailed analysis of flight feather development and moulting in the Black-bellied Sandgrouse, which provides useful ageing criteria based on the patterns of both primary growth and moult.

Plumage development and moult in captive Black-bellied Sandgrouse Pterocles orientalis: age and sex variations

Article

Full-text available

Nov 2018

A guano-derived δ13C and δ15N record of climate since the Medieval Warm Period in north-west Romania

Article

Jul 2018

A 285‐cm core of bat guano was recovered from Măgurici Cave in north‐west Romania and analyzed for δ¹³C, δ¹⁵N and pollen. Guano deposition occurred from AD 881 until 1240 and from AD 1651 to 2013, allowing for the interpretation of summer variations in precipitation and temperature during the Medieval Warm Period (MWP) and the Little Ice Age (LIA). A 2‰ increase in δ¹³C, 1.5‰ decrease in δ¹⁵N, and the presence of Ulmus, Quercus and Carpinus betulus indicate a warm and dry MWP occurred in the region. The lack of deposition during the beginning of the LIA suggests a possible climate‐induced change in prey availability resulting in bats vacating the cave. Variation of δ¹³C values between −25 and −23‰ at AD 1650 (LIA) indicates similar drier conditions as at the end of MWP. However, a 2‰ decrease in δ¹³C values that occurred between AD 1790 and 1900 suggests climate was trending towards wetter conditions at the end of the LIA. From AD 1938 to 2013, δ¹³C values appear to be more influenced by temperature, indicating that this parameter had a more significant effect on carbon discrimination than water availability.

Winter Flock Structure in the Central Monte Desert, Argentina

Article

Full-text available

Oct 2017

Flocking behaviour has been studied for decades around the world, but there is little knowledge of this subject in desert bird communities. We investigate winter flock structure in open woodlands of the central Monte desert, Argentina, during two consecutive years. Of the 22 bird species that were recorded in flocks, most were granivorous. There were differences in flock density between years, probably due to fluctuation in seed abundance. More than half of the observed flocks were composed of different species (i.e. mixed-species flocks). We detected only two regular species (found in more than 75% of flocks): Rufous-collared Sparrow Zonotrichia capensis and Ringed Warbling Finch Poospiza torquata, both granivorous birds. Ringed Warbling Finch and Cinnamon Warbling Finch Poospiza ornata co-occurred at a higher frequency than expected by chance, and formed subgroups within flocks. Many-colored Chaco Finch Saltatricula multicolor, Greater Wagtail-tyrant Stigmatura budytoides, Brown Cacholote Pseudoseisura lophotes and Short-billed Canastero Asthenes baeri were found to form family groups, which may be related to delayed natal dispersal. The observed flocking propensity of granivorous birds and the small number of species per flock were similar to that found in other desert bird communities. We discuss some differences and similarities between granivorous and insectivorous flocking patterns, and propose hypotheses on the plausible causes. Our results provide a basis for a better understanding of the flocking behaviour patterns of birds in arid environments.

Spatiotemporal habitat dynamics of ungulates in unpredictable environments: The khulan (Equus hemionus) in the Mongolian Gobi desert as a case study

Article

Nov 2016
BIOL CONSERV

In resource-poor environments many large herbivores do not perform seasonal migrations but show unpredictable, long-range movements within a given season. The few studies that have examined drivers for within season long-range movements suggest that these movements are a response to spatiotemporal dynamics of foraging resources. We tested this hypothesis and were especially interested in detecting dynamics of foraging habitat which may influence high mobility of khulan, Equus hemionus, during summers in the Dzungarian Gobi of Mongolia. We used six years of ground census data combined with remotely sensed imagery of vegetation productivity (NDVI) to build a dynamic habitat model. We subsequently predicted khulan habitat suitability for each of the seven 16-day NDVI intervals every summer between 2004 and 2009 and examined variability of the resulting 42 prediction maps to characterize spatiotemporal dynamics in khulan foraging habitat. Our analyses showed khulan summer foraging habitat was highly predictable with little spatiotemporal variability making it unlikely that broad scale variability of foraging habitats can explain the high mobility of khulan. The few and small areas that did show khulan habitat variability were related to locations around water sources. In addition, we found that khulan avoided habitats beyond 21 km from water sources. Together these findings suggest that water availability and switching among the sparsely located water bodies rather than broad scale dynamics of foraging habitats may be the key driver for the high mobility of khulan in the Dzungarian Gobi. Our findings highlight the importance of securing access to and connectivity among water bodies for wild ungulates and the need for further studies on possible drivers of nomadic movements in drylands.

The Modern Outback: Nature, people and the future of remote Australia

Book

Full-text available

Oct 2014

This publication is the first in The Outback Papers series, which Pew is commissioning to document one of the the last extensive natural regions left on our planet - its values, threats to its health and the opportunities available to create a modern Outback that values its nature and sustains its people.

Surviving to winter: Strategies of wintering birds in the Iberian Peninsula

Article

Full-text available

Jun 2004

Aims: Climatic conditions during the winter are typically harsher for birds, which have to counteract deteriorating weather by different physiological or behavioural adaptations, or simply by moving to other areas of milder weather (e.g. migrating). The aim of this paper is to review the different adaptations and strategies of birds for surviving the winter, with a special emphasis on the peninsular winter quarters, one of the most suitable geographic areas for the reception of a very important contingent of birds from the western Palaearctic. This suitability is the result of its southern geographic situation which provides a milder climate, of the canalising of the main presaharian migratory routes, and of its topographic variety, diverse landscape and heterogeneity of environments. Results and Conclusions: Key variables explaining the winter distribution of birds in Iberian Peninsula are altitude, vegetation structure and geographic location. Parameters describing land bird communities (density, richness and diversity) can equally be predicted by the same variables. Aquatic environments are affected by the basin in which they are located and by rainfall patterns, which in turn determine the levels of grouping of the different contingents of birds. In order to offset the higher energetic requirements of winter, birds have developed different adaptations: increase the size of fat reserves, store food, increase metabolic rate, and develop different specialized behaviours. The Iberian Peninsula offers a wide range of trophic possibilities: herbs, seeds, bulbs, tubers and rhizomes; fruits, berries and acorns; pine seeds and other arboreal food resources, and invertebrates. In aquatic environments, there are important vegetable resources, aquatic invertebrates and fishes. Finally, the same wintering birds may appear as an important food resource for raptors. Human life and its consequences (garbage and rubbish dumps, fish farms, etc.) have favoured changes in the feeding habits of several species. The exploitation of all these natural resources may give rise to different patterns of spatial use. One of the behavioural strategies most common during winter is the aggregation of individuals in flocks, albeit that some species may hold territorial patterns. Winter flocking entails different costs and benefits, which may be compensated by different strategies such as the formation of heterospecific groups, communal roosting, the establishment of social hierarchies, or the share-out of space by the different classes. Wintering contingents may fluctuate greatly from year to year because of phenomena such as thermal movements, irruptions and altitudinal movements. Winter may have important consequences on the evolutionary patterns of different species, either because some species may pair in this period, or because of the strong selection pressures exerted on them because of the harder weather conditions. Therefore, the consequences of what may happen in winter do not only affect this season, and its study may be of great relevance to the understanding of the whole natural and life history of the different species.

The movement shortfall in bird conservation: Accounting for nomadic, dispersive and irruptive species

Article

Nov 2015
ANIM CONSERV

Efforts to prioritize conservation planning are undermined by several recognized knowledge shortfalls. Here we highlight a further shortfall, which we term the ‘movement shortfall’, in our knowledge of species movements, with particular reference to dispersive, irruptive and nomadic birds. Despite 100 years of ringing effort, the movement characteristics of these species are still poorly known, as the irregularity of their movements and low human population densities in parts of their range impede traditional methods. A lack of understanding of their movements, combined with an inappropriate conservation approach that relies on protected areas and international frameworks, means that the conservation status of these species continues to deteriorate. We call for the application of new tracking technology and outreach initiatives to help formulate innovative conservation approaches that are better suited to species with irregular movement behaviours.

Conserving mobile species

Article

Full-text available

Sep 2014

The distributions of many species are dynamic in space and time, and movements made by individuals range from regular and predictable migrations to erratic, resource-driven nomadism. Conserving such mobile species is challenging; the effectiveness of a conservation action taken at one site depends on the condition of other sites that may be geographically and politically distant (thousands of kilometers away or in another jurisdiction, for example). Recent work has shown that even simple and predictable linkages among sites caused by "to-and-fro" migration can make migratory species especially vulnerable to habitat loss, and substantially affect the results of conservation prioritizations. Species characterized by more erratic or nomadic movements are very difficult to protect through current conservation planning techniques, which typically view species distributions as static. However, collaborations between migration ecologists, conservation planners, and mathematical ecologists are paving the way for improvements in conservation planning for mobile species.

Decline in whistling rat (Parotomys brantsii) density: Possible response to climate change in the Karoo, South Africa

Article

Sep 2022

The burrow systems (warrens) of whistling rat Parotomys brantsii are confined to patches of deep soil (biogenic mounds known as heuweltjies) on stony plains in the arid Succulent Karoo region of South Africa. Whistling rat warrens were recorded on heuweltjies at the Tierberg Long‐Term Ecological Research (LTER) site in the southern Karoo, Western Cape Province, South Africa, on eight occasions between 1988 and 2001. Increasing temperatures over the study period combined with a severe drought from 2015 to 2021 caused a 36% dieback in perennial shrub cover on the research site. The percentage of heuweltjies occupied by whistling rats declined from 44% occupation to 20% occupation between 2005 and 2021 during unusually hot, dry conditions indicated by low values in the Standardised Evapotranspiration Index. Around their warrens, whistling rats had no influence on species richness of perennial plants but reduced vegetation cover. Les systèmes de terriers (‘warrens’) du rat sifflant (Parotomys brantsii) sont confinés à des parcelles de sol profond (monticules biogéniques connus localement sous le nom de ‘heuweltjies’) sur des plaines pierreuses dans la région aride du Karoo Succulent en Afrique du Sud. Des dédales de rats sifflants ont été enregistrés à huit reprises entre 1988 et 2001 sur ces monticules du site de recherche écologique ‘Tierberg Karoo LTER’ dans le sud du Karoo, province du Cap‐Occidental. Une grave sécheresse de 2015 à 2021 a causé un dépérissement de 36% de la couverture arbustive vivace. Le pourcentage de monticules occupés par des rats sifflants est passé de 44% à 20% d'occupation entre 2005 et 2021. Cette baisse est due a des conditions de secheresse et de chaleur exceptionnelles, relevée par l'Index Standardizé d'Evapotranspiration pendant cette période. Les rats n'ont eu aucune influence sur la richesse en espèces de plantes vivaces autour de leurs warrens, mais ont néanmoins réduit la couverture végétale sur les monticules.

Adaptation and Evolution of Bird Migration

Chapter

Jan 2021

Migration in birds is a fascinating biological phenomenon. Migration denotes the annual predictable return movements among breeding and nonbreeding populations of birds. Over millennia, the migration in birds evolved with and by various adaptive mechanisms enabling them to survive in the harshest of the conditions. Migration helps in population differentiation by exposing various groups to different environmental conditions or restricting the chances for a genetic exchange through selection by hybridization or assortative mating. The bird migration routes, also known as flyways, are influenced by various ecological factors. There are broadly eight primary flyways worldwide which are followed for long-distance migration of birds often across continents and large expanses of land and water. Avian migration also impacts human health. In the course of annual migration, birds disseminate many bacterial, viral, fungal, and parasitic diseases or disease-causing agents that affect humans. Birds may act as natural reservoirs (viz. psittacosis, Newcastle disease, avian flu, etc.), may act as asymptomatic carriers (salmonellosis and mite diseases), may disseminate various arthropod vectors of diseases (eastern equine encephalitis, western equine encephalitis, St. Louis encephalitis, etc.) and might create new reservoirs for infections on through fecal pollution of the environment (histoplasmosis, cryptococcosis). Considering the importance of avian migration in spreading of human infections including the zoonotic ones, in this chapter, we look into the basics of avian migrations along with the role of birds in dissemination of zoonotic infections to humans.

Developing an environmental research platform in the Karoo at the Square Kilometre Array

Article

Full-text available

Nov 2021
S AFR J SCI

A part of the Square Kilometre Array (SKA) will be constructed in the northern Karoo of South Africa on approximately 135 000 ha of land. This land is formerly privately owned rangelands (farms) that were purchased by the South African National Research Foundation (NRF), on which the South African Radio Astronomy Observatory, as part of the global SKA project, will erect the SKA infrastructure. Additionally, a long-term environmental research programme will be established to investigate various dryland ecosystem components at a landscape scale. Livestock has been removed from the farms, and the area is now managed by the South African National Parks (SANParks) as the Meerkat National Park. The land-use and land cover changes present an unprecedented opportunity to study ecosystem dynamics. The property will be established as an NRF science park, incorporating an SKA research platform for radio astronomy and an environmental research platform of the South African Environmental Observation Network, with additional environmental research conducted by SANParks and their collaborators. We briefly describe current knowledge of the area’s environment, and report on past and contemporary changes in this part of the Karoo. We present a conceptual model for the larger landscape which considers possible future land-use scenarios, the projected trajectories of change under these scenarios, and factors influencing these trajectories. These deliberations represent the foundation for future research in this landscape and the development of an environmental observation research platform in the Karoo at SKA. Significance: • We summarise an extensive environmental baseline report on the SKA property and surrounding areas. • Withdrawal of livestock and other changes – such as clearing of alien invasive plants, reduced predator control and reduction in water-point maintenance – are expected to bring about changes in ecological processes and plant and animal communities. • We present a conceptual model of scenarios to test possible future trajectories as a first step towards an earth system science research platform in the NRF science park.

Where nothing stands still: quantifying nomadism in Australian arid-zone birds

Article

Full-text available

Jan 2022
LANDSCAPE ECOL

Context Nomadism is a movement strategy in response to non-seasonal environmental variability. Knowledge of nomadic species movements is poor but is necessary to understand life histories and develop appropriate conservation strategies. Objectives We provide a first quantification of nomadism among Australia’s arid bird community, which is presumed to be highly nomadic, by measuring variation in species’ occurrence and abundance among years to determine whether there are clear nomadic and non-nomadic strategists. Methods We surveyed birds annually from 2012 to 2016. We measured how many years each species was present at a site and estimated inter-annual variability in species abundance, using both measures to infer species movement patterns. We used results to inform existing movement classifications. Results Most arid species showed low site persistence, with species detected at the same site, on average, 1.8 out of the five survey years. Movement varied along a continuum rather than grouping into distinct nomadic and non-nomadic groups. Species classified as nomadic showed higher variation in abundance and lower site persistence than species classified as resident. Our method of quantifying nomadism closely replicated existing expert-derived movement classifications of arid zone bird species. Conclusions Rather than a fixed attribute, movements of many species in our study can be heavily environment-dependent, and individuals of a single species can display a continuum of movements in different times and places. This complicates the conservation of species, but the growing recognition of the complexity of species movements offers opportunities for a more nuanced understanding of the relationship between species and environment.

Long-Term Population Dynamics of Namib Desert Tenebrionid Beetles Reveal Complex Relationships to Pulse-Reserve Conditions

Article

Full-text available

Sep 2021

Joh R. Henschel

Noy-Meir’s paradigm concerning desert populations being predictably tied to unpredictable productivity pulses was tested by examining abundance trends of 26 species of flightless detritivorous tenebrionid beetles (Coleoptera, Tenebrionidae) in the hyper-arid Namib Desert (MAP = 25 mm). Over 45 years, tenebrionids were continuously pitfall trapped on a gravel plain. Species were categorised according to how their populations increased after 22 effective rainfall events (>11 mm in a week), and declined with decreasing detritus reserves (97.7–0.2 g m−2), while sustained by nonrainfall moisture. Six patterns of population variation were recognised: (a) increases triggered by effective summer rainfalls, tracking detritus over time (five species, 41% abundance); (b) irrupting upon summer rainfalls, crashing a year later (three, 18%); (c) increasing gradually after series of heavy (>40 mm) rainfall years, declining over the next decade (eight, 15%); (d) triggered by winter rainfall, population fluctuating moderately (two, 20%); (e) increasing during dry years, declining during wet (one, 0.4%); (f) erratic range expansions following heavy rain (seven, 5%). All species experienced population bottlenecks during a decade of scant reserves, followed by the community cycling back to its earlier composition after 30 years. By responding selectively to alternative configurations of resources, Namib tenebrionids showed temporal patterns and magnitudes of population fluctuation more diverse than predicted by Noy-Meir’s original model, underpinning high species diversity.

Fire, drought and flooding rains: The effect of climatic extremes on bird species’ responses to time since fire

Article

Full-text available

May 2021
DIVERS DISTRIB

Aim Climatic extremes and fire affect ecosystems across the globe, yet our understanding of how species are influenced by the interaction of these broadscale ecological drivers is poorly understood. Using a ten‐year dataset, we tested how extreme drought and rainfall interacted with time since fire (TSF) to shape bird species’ distributions. Location Semi‐arid mallee woodlands of south‐eastern Australia. Methods We quantified the effects of climatic extremes on bird species’ occurrence, species richness and incidence at 180 sites across three climatic periods—an El Niño‐associated drought (the “Big Dry”), immediately after La Niña drought‐breaking rainfall (“Big Wet”) and three years following the La Niña event (“Post‐Big Wet”). We then compared species’ responses with TSF across the three climatic periods using a chronosequence of sites from 1 to 117 years post‐fire. Results La Niña rainfall had sustained impacts on species’ occurrence. Over half of species increased significantly during the Big Wet. Despite three intervening years of below‐average rainfall, three quarters of these species remained comparably high, Post‐Big Wet. By contrast, less than half of threatened and declining species benefited from high rainfall. Responses of species to TSF were found to differ contingent on climatic conditions: almost twice as many species responded to TSF during the Big Wet and almost three times as many Post‐Big Wet, compared with the Big Dry. Across climatic periods, a majority of species showed preference for mid to older post‐fire vegetation. Main conclusions Variation in responses to TSF is likely due to the effect of climatic variation on resources. We suggest that, at sites of different post‐fire age, interactions between TSF and climate may differentially influence both the availability and longevity of resources. Given climatic extremes are predicted to become increasingly severe with climate change, accounting for their influence on fauna–fire dynamics will require careful management of fire.

Local extinctions exceed colonization rates in a bird community during dry years in the Brazilian Caatinga

Article

Full-text available

Aug 2020

Droughts typically result in a widespread decline in many vertebrate populations and even the local extinction of some species. However, different species vary considerably in their resistance to the effects of drought. This study aimed to estimate the relative species richness and the colonization and extinction rates in a bird community during an acute drought event in the Brazilian Caatinga. We mist-netted birds during 3 years throughout seven field seasons in two sampling plots to estimate community parameters using multi-season dynamic occupancy models. The relative richness to the regional species pool varied considerably during the study period (16–49%) with markedly low values in the severe onset of the drought. The estimates in the savanna were higher than those in the shrubby-woodland plot (~ 42 vs ~ 31 species, respectively). Pollinators and seed dispersers were characterized by median to high colonization (30–69%) and local extinction rates (37–69%), indicating low site fidelity. By contrast, granivores and insectivores made up the resident component of the community, with low local extinction and colonization rates (< 30%). Our results indicate that the diversity of Caatinga bird assemblages may decline markedly during severe droughts, primarily as a result of the displacement of species that exploit resources whose availability decreases drastically in abnormally dry years. Considering the climate scenarios predicted for tropical arid and semiarid regions worldwide, we believe that pollinators and seed dispersers will be especially vulnerable to population decline and local extinctions, which will alter community structure and the persistence of ecosystem services.

Variability in nomadism: environmental gradients modulate the movement behaviors of dryland ungulates

Article

Full-text available

Nov 2019

Studying nomadic animal movement across species and ecosystems is essential for better understanding variability in nomadism. In arid environments, unpredictable changes in water and forage resources are known drivers of nomadic movements. Water resources vary temporally but are often spatially stationary, whereas foraging resources are often both temporally and spatially variable. These differences may lead to different types of nomadic movements: forage‐ vs. water‐driven nomadism. Our study investigates these two different types of nomadism in relation to resource gradients from mesic steppe to xeric desert environments in Mongolia's Gobi‐Steppe Ecosystem. We hypothesized that in the desert, where water is a key resource, animals are more water‐dependent and may show water‐driven nomadism with frequent revisits to spatially fixed resources, while in the steppe, animals are less water‐dependent and may show forage‐driven nomadism, tracking high‐quality foraging patches with infrequent revisits to previously used resources. We utilized GPS movement data from 40 individuals of four ungulate species (Mongolian gazelle, goitered gazelle, saiga antelope, and Asiatic wild ass) in the Gobi‐Steppe Ecosystem. We calculated displacement distances and recursion metrics and subsequently performed a principal component analysis to quantify the variation in movement patterns. The satellite‐derived vegetation greenness served as a proxy for the resource gradient and was associated with variation in movement behaviors described by the first principal component, demonstrating that the variability in movements was closely related to the resource gradient from mesic to xeric habitats. We showed that ungulates in the resource‐rich steppe tended to move long distances with few revisits (forage‐driven nomadism), while ungulates in the resource‐poor desert tended to move shorter distances with more revisits (water‐driven nomadism). Our results suggest that xeric and mesic habitats promote different types of nomadic strategies. These results have important implications for conservation strategies: Forage‐driven nomads primarily require a high degree of landscape‐level permeability, and water‐driven nomads additionally require the protection of ephemeral water bodies and actions to maintain the functional connectivity between them.

Introduction to the Karoo Special Issue: Trajectories of Change in the Anthropocene

Article

Dec 2018

The Karoo is an arid to semi-arid area across the western third of South Africa, comprising the Succulent Karoo and Nama-Karoo biomes. Its environment and people have experienced considerable changes, and now face new challenges as the Anthropocene unfolds. This Karoo Special Issue (KSI) brings together new information in 20 papers, a mixture of reviews, research articles and commentaries, significantly adding to previous syntheses of Karoo knowledge. The KSI comprises several sections focusing on different aspects of change, namely a lead article that provides an overview of social and environmental changes, followed by papers concerning changes over time from deep history to contemporary conditions (Xhaeruh to Karoo), insights from long-term studies at several sites across the area, different perspectives of ecosystem processes, and ending with a set of reflections and proposals for research priorities. We end this introduction by dedicating the KSI to two outstanding scholars of the Karoo: Dr Suzanne J Milton and Dr W Richard J Dean. These KSI papers, many of which were written by their colleagues, friends and former students, represents a Festschrift that celebrates and honours their research as well as the inspiration and leadership they gave to a generation of scientists.

A guide to calculating habitat-quality metrics to inform conservation of highly mobile species

Article

Jan 2018

Many metrics exist for quantifying the relative value of habitats and pathways used by highly mobile species. Properly selecting and applying such metrics requires substantial background in mathematics and understanding the relevant management arena. To address this multidimensional challenge, we demonstrate and compare three measurements of habitat quality: graph‐, occupancy‐, and demographic‐based metrics. Each metric provides insights into system dynamics, at the expense of increasing amounts and complexity of data and models. Our descriptions and comparisons of diverse habitat‐quality metrics provide means for practitioners to overcome the modeling challenges associated with management or conservation of such highly mobile species. Whereas previous guidance for applying habitat‐quality metrics has been scattered in diversified tracks of literature, we have brought this information together into an approachable format including accessible descriptions and a modeling case study for a typical example that conservation professionals can adapt for their own decision contexts and focal populations. Considerations for Resource Managers Management objectives, proposed actions, data availability and quality, and model assumptions are all relevant considerations when applying and interpreting habitat‐quality metrics. Graph‐based metrics answer questions related to habitat centrality and connectivity, are suitable for populations with any movement pattern, quantify basic spatial and temporal patterns of occupancy and movement, and require the least data. Occupancy‐based metrics answer questions about likelihood of persistence or colonization, are suitable for populations that undergo localized extinctions, quantify spatial and temporal patterns of occupancy and movement, and require a moderate amount of data. Demographic‐based metrics answer questions about relative or absolute population size, are suitable for populations with any movement pattern, quantify demographic processes and population dynamics, and require the most data. More real‐world examples applying occupancy‐based, agent‐based, and continuous‐based metrics to seasonally migratory species are needed to better understand challenges and opportunities for applying these metrics more broadly.

Long‐distance flights and high‐risk breeding by nomadic waterbirds on desert salt lakes

Article

Oct 2017
CONSERV BIOL

en Understanding and conserving mobile species presents complex challenges, especially for animals in stochastic or changing environments. Nomadic waterbirds must locate temporary water in arid biomes where rainfall is highly unpredictable in space and time. To achieve this they need to travel over vast spatial scales and time arrival to exploit pulses in food resources. How they achieve this is an enduring mystery. We investigated these challenges in the colonial‐nesting Banded Stilt (Cladorhynchus leucocephalus), a nomadic shorebird of conservation concern. Hitherto, Banded Stilts were hypothesized to have only 1–2 chances to breed during their long lifetime, when flooding rain fills desert salt lakes, triggering mass‐hatching of brine shrimp. Over 6 years, we satellite tagged 57 individuals, conducted 21 aerial surveys to detect nesting colonies on 14 Australian desert salt lakes, and analyzed 3 decades of Landsat and MODIS satellite imagery to quantify salt‐lake flood frequency and extent. Within days of distant inland rainfall, Banded Stilts flew 1,000–2,000 km to reach flooded salt lakes. On arrival, females laid over half their body weight in eggs. We detected nesting episodes across the species’ range at 7 times the frequency reported during the previous 80 years. Nesting colonies of thousands formed following minor floods, yet most were subsequently abandoned when the water rapidly evaporated prior to egg hatching. Satellite imagery revealed twice as many flood events sufficient for breeding‐colony initiation as recorded colonies, suggesting that nesting at remote sites has been underdetected. Individuals took risk on uncertain breeding opportunities by responding to frequent minor flood events between infrequent extensive flooding, exemplifying the extreme adaptability and trade‐offs of species exploiting unstable environments. The conservation challenges of nest predation by overabundant native gulls and anthropogenic modifications to salt lakes filling frequencies require investigation, as do the physiological and navigational mechanisms that enable such extreme strategies. Abstract es Vuelos de Larga Distancia y la Reproducción de Alto Riesgo de Aves Acuáticas Nómadas en Lagos Salados de los Desiertos Resumen El entendimiento y la conservación de especies móviles presentan retos complejos, especialmente para animales en ambientes estocásticos o cambiantes. Las aves acuáticas nómadas deben ubicar agua temporal en biomas áridos en los que la precipitación es altamente impredecible en el tiempo y el espacio. Para lograr esto necesitan tiempo de arribo y trasladarse sobre escalas espaciales amplias para explotar los pulsos de recursos alimenticios. Cómo logran esto es un misterio que perdura. Investigamos estos retos con la cigüeñuela pechirroja (Cladorhynchus leucocephalus), un ave costera nómada de anidamiento colonial e interés de conservación. Hasta la fecha se creía que la cigüeñuela pechirroja sólo tenía entre una y dos oportunidades de reproducción a lo largo de su vida cuando la lluvia llena los lagos salados de los desiertos, activando una eclosión masiva de artemias. Durante seis años etiquetamos con satélite a 57 individuos, realizamos 21 censos aéreos para detectar las colonias de anidación en 14 lagos salados del desierto en Australia, y analizamos tres décadas de imágenes satelitales de Landsat y MODIS para cuantificar la frecuencia y extensión de las inundaciones en los lagos salados. A los pocos días de las lluvias distantes tierra adentro, las cigüeñuelas pechirrojas volaron 1,000 – 2,000 km para llegar a los lagos salados inundados. A su llegada, las hembras pusieron más de la mitad de su peso corporal en huevos. Detectamos episodios de anidamiento a lo largo de la extensión de la especie siete veces más que la frecuencia reportada durante los 80 años previos. Se formaron colonias de anidamiento de miles de individuos después de inundaciones menores, aunque la mayoría fueron abandonadas subsecuentemente cuando el agua se evaporó rápidamente antes de la eclosión de los huevos. Las imágenes satelitales revelaron el doble de eventos de inundaciones suficientes para la iniciación de colonias reproductivas que las colonias registradas, lo que sugiere que la anidación en sitios remotos no ha sido detectada. Los individuos tomaron riesgos con oportunidades de reproducción inciertas al responder a eventos frecuentes de inundación menor entre las inundaciones extensivas poco frecuentes, ejemplificando la adaptabilidad extrema y las compensaciones de las especies que explotan los ambientes inestables. Los retos de conservación con la depredación de los nidos por gaviotas nativas sobreabundantes y las modificaciones antropogénicas de las frecuencias de inundación de los lagos salados requieren investigación, así como los mecanismos fisiológicos y de navegación que permiten tales estrategias extremas.

Nuevos registros de distribución del gorrión de Worthen Spizella wortheni en San Luis Potosí, México

Article

Full-text available

Aug 2015

El rango de distribución restringido y el pequeño tamaño poblacional del gorrión de Worthen han ocasionado que esta ave sea considerada una especie amenazada en México y a nivel internacional. Aquí reportamos nuevos registros de esta ave los cuales expanden su rango de distribución conocido en los últimos cuarenta años y abren la posibilidad del uso de hábitats adicionales que no habían sido documentados anteriormente. Por lo tanto es importante realizar esfuerzos para documentar posible actividad reproductiva en estos hábitats.

The importance of incorporating functional habitats into conservation planning for highly mobile species in dynamic systems

Article

Jan 2017
CONSERV BIOL

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, with serious implications for 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. Here we quantify dynamic change in availability and use of key ecological resources required for breeding (i.e. food and nesting sites) for a critically endangered nomadic habitat specialist, the swift parrot (Lathamus discolor). We compare estimates of occupied habitat (km2) derived from dynamic presence-background data climatic models to those derived from dynamic occupancy models that include a direct measure of food availability. We also compare estimates that incorporate fine resolution information on key ecological resources (i.e functional habitats) into distribution maps with more common approaches that typically focus on broader climatic suitability. For all models, both the extent and spatial location of occupied areas varied dramatically over the study period. The occupancy models produced significantly smaller (up to an order of magnitude) and more spatially discrete estimates of occupied habitat than climate-based models. Estimates accounting for the area of functional habitats were also significantly smaller than estimates based only on occupied habitat. Importantly, an increase (or decrease) in one functional habitat did not necessarily correspond to changes in the other, with consequences for overall habitat functionality. We argue that these patterns are typical for mobile resource specialists, but currently go unnoticed due to limited data on (1) species’ presence/absence and (2) 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. This article is protected by copyright. All rights reserved

The role of refuges in the persistence of Australian dryland mammals

Article

Dec 2015

Irruptive population dynamics are characteristic of a wide range of fauna in the world's arid (dryland) regions. Recent evidence indicates that regional persistence of irruptive species, particularly small mammals, during the extensive dry periods of unpredictable length that occur between resource pulses in drylands occurs as a result of the presence of refuge habitats or refuge patches into which populations contract during dry (bust) periods. These small dry-period populations act as a source of animals when recolonisation of the surrounding habitat occurs during and after subsequent resource pulses (booms). The refuges used by irruptive dryland fauna differ in temporal and spatial scale from the refugia to which species contract in response to changing climate. Refuges of dryland fauna operate over timescales of months and years, whereas refugia operate on timescales of millennia over which evolutionary divergence may occur. Protection and management of refuge patches and refuge habitats should be a priority for the conservation of dryland-dwelling fauna. This urgency is driven by recognition that disturbance to refuges can lead to the extinction of local populations and, if disturbance is widespread, entire species. Despite the apparent significance of dryland refuges for conservation management, these sites remain poorly understood ecologically. Here, we synthesise available information on the refuges of dryland-dwelling fauna, using Australian mammals as a case study to provide focus, and document a research agenda for increasing this knowledge base. We develop a typology of refuges that recognises two main types of refuge: fixed and shifting. We outline a suite of models of fixed refuges on the basis of stability in occupancy between and within successive bust phases of population cycles. To illustrate the breadth of refuge types we provide case studies of refuge use in three species of dryland mammal: plains mouse (Pseudomys australis), central rock-rat (Zyzomys pedunculatus), and spinifex hopping-mouse (Notomys alexis). We suggest that future research should focus on understanding the species-specific nature of refuge use and the spatial ecology of refuges with a focus on connectivity and potential metapopulation dynamics. Assessing refuge quality and understanding the threats to high-quality refuge patches and habitat should also be a priority. To facilitate this understanding we develop a three-step methodology for determining species-specific refuge location and habitat attributes. This review is necessarily focussed on dryland mammals in continental Australia where most refuge-based research has been undertaken. The applicability of the refuge concept and the importance of refuges for dryland fauna conservation elsewhere in the world should be investigated. We predict that refuge-using mammals will be widespread particularly among dryland areas with unpredictable rainfall patterns.

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Nomadic Desert Birds

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