Connectivity and bottlenecks in a migratory wildebeest<i>Connochaetes taurinus</i>population

Morrison, Thomas A.; Bolger, Douglas T.

doi:10.1017/s0030605313000537

Cited by 53 publications

(59 citation statements)

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“…We believe these conflicting results may underscore behavioral differences underlying collar data collected during the northward migration, versus detection data collected throughout the year. Our GPS collar data indicated that animals moved quickly northwards from Manyara Ranch towards the breeding grounds once the 445 rains began, often traveling at night through bottlenecks and across high-traffic roads (Morrison and Bolger 2014). Therefore, the collar data likely reflected wildebeest movements during an active migratory state, when animals were moving through open areas such as grasslands without necessarily stopping frequently to forage.…”

Section: Correlates Of Wildebeest Habitat Selectionmentioning

confidence: 85%

“…The TE contains a patchwork of reserves, including two national parks, Lake Manyara and Tarangire, as well as Manyara Ranch Conservancy (Fig. 1) that support high wildlife densities during the dry season, but all migratory routes and wet-season calving grounds lie outside formally protected areas (Morrison and Bolger 2014), and movement corridors in the ecosystem are considered to be at 120 high risk of disappearing within the near future (Caro et al 2009;Morrison and Bolger 2014;Morrison et al 2016). …”

Section: Study Areamentioning

confidence: 99%

“…TAM deployed the GPS collars (Telonics TGW-4780H) on 10 and 11 October 2011 in Manyara Ranch as described by Morrison and Bolger (2014). The male's collar collected data at intervals of 4 hours for 75 days, while the female's collar recorded locations at 12-hr intervals (noon and midnight) for 14 days.…”

Section: Gps Collar Relocation Data 150mentioning

confidence: 99%

“…However, migrations are in precipitous decline globally 35 because of rapid environmental change in many of the landscapes in which they still occur (Bolger et al 2008;Harris et al 2009;Singh and Milner-Gulland 2011). The linear shape of many corridors (Sawyer et al 2009) make migrations particularly sensitive to the effects of habitat loss and fragmentation, particularly in areas that act as natural bottlenecks such as valleys or passes (Morrison and Bolger 2014). Recent efforts to quantitatively delineate and validate 40 corridors to conserve migratory species and their associated ecological services have significantly improved the resolution and accuracy of corridor planning, but relatively little effort has been made to compare amongst the many types of data and analyses that form the basis of corridor prediction (Berger 2004;Sawyer et al 2009;Epps et al 2011;Poor et al 2012;McClure et al 2016).…”

mentioning

confidence: 99%

“…These routes were highlighted by Bolger et al (2008) and Caro et al (2009) as requiring extremely urgent action to protect known animal movements. Morrison and Bolger (2014) outlined an approximate wildebeest migratory route through this landscape (Fig. 1), but a more explicit delineation of wildebeest migratory corridors is required to inform land-use planning for wildlife conservation.…”

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confidence: 99%

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A multi-method approach to delineate and validate migratory corridors

et al. 2017

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A multi-method approach to delineate and validate migratory corridors. Landscape Ecology, 32(8), pp. 1705Ecology, 32(8), pp. -1721Ecology, 32(8), pp. . (doi:10.1007 This is the author's final accepted version.There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it.http://eprints.gla.ac.uk/143652/ Objectives We present a multi-method approach for delineating and validating wildlife corridors 5 using multiple data sources, which can be used conserve landscape connectivity. We used this approach to delineate and validate migration corridors for wildebeest (Connochaetes taurinus) in the Tarangire Ecosystem of northern Tanzania.Methods We used two types of locational data (distance sampling detections and GPS collar locations), and three modeling methods (negative binomial regression, logistic regression, and 10 Maxent), to generate resource selection functions and define resistance surfaces. We compared two corridor detection algorithms (cost-distance and circuit theory), to delineate corridors. We validated corridors by comparing random and wildebeest locations that fell within corridors, and cross-validated by data type.Results Both data types produced similar resource selection functions. Wildebeest consistently 15 selected migration habitat in flatter terrain farther from human settlements. Validation indicated three of the combinations of data type, modeling, and corridor detection algorithms (detection data with Maxent modeling, GPS collar data with logistic regression modeling, and GPS collar data with Maxent modeling, all using cost-distance) far outperformed the other seven. We merged the predictive corridors from these three data-method combinations to reveal habitat with 20 highest probability of use.Conclusions The use of multiple methods ensures that planning is able to prioritize conservation of migration corridors based on all available information.3

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Section: Correlates Of Wildebeest Habitat Selectionmentioning

confidence: 85%

Section: Study Areamentioning

confidence: 99%

Section: Gps Collar Relocation Data 150mentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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A multi-method approach to delineate and validate migratory corridors

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Anthropogenic and climatic drivers of population densities in an African savanna ungulate community

Bierhoff,

Bond,

Ozgul

et al. 2024

Population Ecology

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Many ungulate species in Africa range in habitats that vary in type and quality over space and time, but ongoing environmental change is substantially altering their habitats. Identifying key environmental variables that regulate ungulate population densities can guide management actions for effective conservation. We studied the local population density responses of a community of sympatric ungulate species in the Tarangire Ecosystem of northern Tanzania, to a suite of environmental factors that vary over space and time, to quantify population trends, determine the primary environmental correlates of densities, and identify covariation in densities among species. We estimated seasonal densities of five commonly detected species (impala, dik–dik, Grant's gazelle, eland, and waterbuck) based on 7 years of distance‐sampling data from 41 replicate surveys of 237 line transects. We systematically analyzed the effects of spatial, seasonal, and annual environmental covariates on variation in transect species‐specific densities across space and time. Large fluctuations in climatic factors mediated highly synchronous temporal density variation among all species. We documented more spatial than temporal variation in four of the five species, suggesting that spatial heterogeneity may provide some buffer against temporal variation in the environment. Protection of sufficient habitats and water sources should allow ungulates to respond to a temporally changing world by moving across space. Further, among‐species covariation patterns identified two potential ungulate guilds (impala—dik–dik—waterbuck; eland—Grant's gazelle) that should aid in developing efficient and coordinated management actions.

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Habitat loss on seasonal migratory range imperils an endangered ungulate

Williams

Steenweg

Hegel

et al. 2021

Ecol Sol and Evidence

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1. Endangered species policies and their associated recovery documents and management actions do not always sufficiently address the importance of migratory behaviour and seasonal ranges for imperilled populations. 2. Using a telemetry location dataset spanning 1981-2018, we tested for changes in prevalence of migratory tactics (resident, migrant) over time, switching between tactics, shifts in seasonal space use including migration corridors, and survival consequences of migrant and resident tactics for 237 adult female endangered woodland mountain caribou in one population in western Canada. 3. Over more than three decades, the proportion of individuals displaying annual migration to the low elevation forested winter range declined from nearly 100%-38%. Correspondingly, there was a strong switch away from being migrant to being year-round residents at high elevation. 4. These behavioural changes corresponded to abandonment of low elevation winter ranges in association with increasing levels of anthropogenic land uses, including forestry and oil and gas developments. Furthermore, there were no identifiable migration corridors to target for migratory route protection. 5. These shifts translated to lower survival rates, particularly for caribou demonstrating resident tactics, consistent with recent declines of the caribou population. That migrants switched to residency in their largely undisturbed summer range, despite lower survival, indicates maladaptive habitat selection consistent with recent patterns of mountain caribou extirpations. 6. Globally, endangered species policies and their associated recovery plans and management actions often do not explicitly consider the challenge of protecting migratory species. Effective conservation of migratory species requires protecting critical This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Connectivity and bottlenecks in a migratory wildebeestConnochaetes taurinuspopulation

Cited by 53 publications

References 35 publications

A multi-method approach to delineate and validate migratory corridors

A multi-method approach to delineate and validate migratory corridors

Anthropogenic and climatic drivers of population densities in an African savanna ungulate community

Habitat loss on seasonal migratory range imperils an endangered ungulate

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