Conserving migratory and nomadic species

Abstract

Migration is an incredible phenomenon. Across cultures it moves and inspires us, from the first song of a migratory bird arriving in spring, to the sight of thousands of migratory wildebeest thundering across African plains. Not only important to us as humans, migratory species play a major role in ecosystem functioning across the globe. Migratory species use multiple landscapes and can have dramatically different ecologies across their lifecycle, making huge contributions to resource fluxes and nutrient transport. However, migrants around the world are in decline. In this thesis I examine our conservation response to these declines, exploring how well current approaches account for the unique needs of migratory species, and develop ways to improve on these. The movements of migratory species across time and space make their conservation a multidimensional problem, requiring actions to mitigate threats across jurisdictions, across habitat types and across time. Incorporating such linkages can make a dramatic difference to conservation success, yet migratory species are often treated for the purposes of conservation planning as if they were stationary, ignoring the complex linkages between sites and resources. In this thesis I measure how well existing global conservation networks represent these linkages, discovering major gaps in our current protection of migratory species. I then go on to develop tools for improving conservation of migratory species across two areas: prioritizing actions across species and designing conservation networks.Protected areas are one of our most effective conservation tools, and expanding the global protected area estate remains a priority at an international level. Globally, about 12.9% of the landscape is covered by protected areas, and in Chapter 2 I examine how well migratory birds are represented within current protected areas, specifically taking into account their need for protection across the annual cycle. I discover that just 9% of migratory birds meet standard protection targets across all parts of their migratory distribution, their breeding, non-breeding and passage distributions, in stark contrast to the 45% of non-migratory birds meeting the same targets. There is currently a major push to increase the size and comprehensiveness of the global protected area estate, and these findings highlight the need for greater emphasis on collaboration across nations to incorporate migratory connectivity into our approaches to protected area placement.One of the challenges to incorporating migratory connectivity into systematic conservation planning is that often we have only a poor understanding of the patterns of movements of migratory species ii in space and time. In Chapter 3 and 4 I develop a tool for discovering spatial dynamics in highly mobile yet data-poor species, unlocking valuable information for improved extinction risk assessment and conservation planning. Using Australian arid-zone nomadic birds as a case study, I reveal enormous variability in predicted spa...

Solving problems of conservation inadequacy for nomadic birds

“…A dynamic modelling approach was recently used to predict time-sliced distributions for 43 nomadic birds found across the arid and semi-arid parts of Australia (Runge et al 2015). The data used to populate these models were citizen science records over the past decade -a resource that has in the past been discounted by researchers over traditional localised long-term monitoring protocols, but shows promise as one of the best (and possibly only) ways to explore nomadic distributions over large poorly-surveyed areas such as the arid interior of Australia (Tulloch et al 2013a).…”

Migration in butterflies: a global overview

“…Distances travelled vary greatly, with some species making just local movements (Denno & Grissell, 1979; Denno et al ., 1980; Denno, Douglas & Jacobs, 1985), and others traveling thousands of kilometres between continents and even hemispheres (Alerstam et al ., 2003; Chapman, Reynolds & Wilson, 2015). From a conservation viewpoint, the often‐vast geographic range sizes of migratory species might be assumed to protect them from extinction risk, yet migratory species can be acutely prone to threats occurring at key sites where they congregate at some point in the annual cycle (Koh & Sodhi, 2004; Wilcove & Wikelski, 2008; Flockhart et al ., 2015; Runge, 2015; Runge et al ., 2015; Stenoien et al ., 2016; Dhanjal‐Adams et al ., 2017; Gao et al ., 2020; Chowdhury et al ., 2021 b ). For example, habitat destruction and fragmentation, coupled with intense human predation led to the extinction of at least three formerly widespread and common migratory species: the Rocky mountain grasshopper Melanoplus spretus , the passenger pigeon Ectopistes migratorius , and Eskimo curlew Numenius borealis (Brower & Malcolm, 1991; Bucher, 1992; Hopkins, 2005; Harris et al ., 2012).…”

Assessing bird migrations

“…For example, changes in the timing of nesting and migration of some bird species are linked to the emergence of disease in plants, because of the reduced ability of insectivorous birds to control populations of plant-eating insects (Whelan et al 2015). Although extinction of migration may not necessarily result in extinction of the taxon, given the importance of species' migrations in regulating ecosystems, conserving migration as a phenomenon is as important as conserving the species themselves (Runge 2014).…”

“…Understanding the migratory status of species is an important foundation for comparative studies and conservation decisions, such as establishing protected areas and assessing species extinction risk (Runge et al 2014;Mazor et al 2016). Migrants depend on a series of suitable habitats at specific times in their breeding and non-breeding ranges and along their migratory route (Runge et al 2014) and so are disproportionally impacted as a function of all the threats occurring along their range (Jonzen et al 2006;Iwamura et al 2013). Additionally, migrants and non-migrants are assessed differently within the IUCN Red List; consequently, any misunderstanding of a species' movements may lead to the wrong extinction risk category being applied (Runge et al 2015a).…”