A Cosmic View of ‘Tundra Gardens’: Satellite Imagery Provides a Landscape-Scale Perspective of Arctic Fox Ecosystem Engineering

Johnson‐Bice, Sean M.; Roth, James D.; Markham, James W.

doi:10.1007/s10021-023-00857-x

Cited by 3 publications

(6 citation statements)

References 71 publications

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“…However, because it is virtually impossible to collar all neighbors from a given area (e.g., foxes transiting, leaving, or settling after we left), we captured small groups of neighbors scattered throughout the whole study area. Average distance between neighbors in April varies between 5.4 and 7.7 km [ 31 ], and we know the locations of all dens in the area where we trap [ 31 , 44 ]. We can, therefore, ensure that no other fox lives between the neighbors we caught.…”

Section: Methodsmentioning

confidence: 99%

Coexistence of two sympatric predators in a transitional ecosystem under constraining environmental conditions: a perspective from space and habitat use

Warret Rodrigues,

Roth

2023

Mov Ecol

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Background Range expansion of species, a major consequence of climate changes, may alter communities substantially due to competition between expanding and native species. Methods We first quantified size differences between an expanding habitat generalist, the red fox (Vulpes vulpes), and a circumpolar habitat specialist, the Arctic foxes (Vulpes lagopus), at the edge of the Arctic, where climate-related changes occur rapidly, to predict the likelihood of the larger competitor escalating interference to intraguild killing. We then used satellite telemetry to evaluate competition in a heterogeneous landscape by examining space use early during the foxes' reproductive period, when resource scarcity, increased-food requirements and spatial constraints likely exacerbate the potential for interference. We used time-LoCoH to quantify space and habitat use, and Minta's index to quantify spatio-temporal interactions between neighbors. Results Our morphometric comparison involving 236 foxes found that the potential for escalated interference between these species was high due to intermediate size difference. However, our results from 17 collared foxes suggested that expanding and native competitors may coexist when expanding species occur at low densities. Low home-range overlap between neighbors suggested territoriality and substantial exploitation competition for space. No obvious differential use of areas shared by heterospecific neighbors suggested low interference. If anything, intraspecific competition between red foxes may be stronger than interspecific competition. Red and Arctic foxes used habitat differentially, with near-exclusive use of forest patches by red foxes and marine habitats by Arctic foxes. Conclusion Heterogeneous landscapes may relax interspecific competition between expanding and native species, allowing exclusive use of some resources. Furthermore, the scarcity of habitats favored by expanding species may emphasize intraspecific competition between newcomers over interspecific competition, thus creating the potential for self-limitation of expanding populations. Dominant expanding competitors may benefit from interference, but usually lack adaptations to abiotic conditions at their expansion front, favoring rear-edge subordinate species in exploitation competition. However, due to ongoing climate change, systems are usually not at equilibrium. A spread of habitats and resources favorable to expanding species may promote higher densities of antagonistically dominant newcomers, which may lead to extirpation of native species.

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Section: Methodsmentioning

confidence: 99%

Coexistence of two sympatric predators in a transitional ecosystem under constraining environmental conditions: a perspective from space and habitat use

Warret Rodrigues,

Roth

2023

Mov Ecol

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“…2A), earning them the nickname 'gardens of the tundra.' Arctic fox dens are large enough that the productivity and phenology of den vegetation can be studied from satellite imagery (Johnson-Bice et al 2023).…”

Section: Box 2 Case Study: Arctic Fox Dens Are Ecological Hotspots On...mentioning

confidence: 99%

“…Surveys are likely one of the easiest ways to quantify home site density. For instance, census survey methods have been used to quantify Arctic fox den density (Johnson-Bice et al 2023), and thus the landscape-scale impact fox denning behavior has on other tundra species. If predator home sites (or colonies, haul-outs) vary in size, these size-dependent effects can be accounted for when quantifying their broader scale impact (Bokhorst et al 2019).…”

Section: Quantifying Patchy Indirect Effects Of Predation At Local An...mentioning

confidence: 99%

“…They instead re‐use the same dens for decades – even centuries – to raise pups (Macpherson 1969). For instance, in Manitoba, Canada, Arctic foxes re‐use the same dens year after year presumably because suitable den sites are restricted to elevated beach ridges that are easy to excavate and prevent the den from flooding during snowmelt (Johnson‐Bice et al 2023). As foxes repeatedly occupy the dens, the decay of accumulated prey remains and fox excrement increases soil nutrient concentration and plant production (Smith et al 1992, Gharajehdaghipour et al 2016), resulting in nutritionally enriched, and locally diverse, plant communities on Arctic fox dens (Bruun et al 2005, Fafard et al 2020).…”

Section: Nutrient Accumulation Pathway: Predators Create Biogeochemic...mentioning

confidence: 99%

“…For instance, invertebrate and plant characteristics can be directly compared at a carcass or nutrient accumulation patch with nearby reference sites (Ben‐David et al 1998, Bump et al 2009b, Barton et al 2016, Gharajehdaghipour et al 2016, Barry et al 2019). Alternatively, quantitative models based on the characteristics of carcass or nutrient patches could be used to generate reference locations matching the nutrient patch characteristics for comparison (Johnson‐Bice et al 2023). Manipulative experiments or remotely sensed trail cameras can be used to evaluate food web‐related effects that occur in and around patches (Cortés‐Avizanda et al 2009a, Ruprecht et al 2021, Spencer et al 2021, Zhao et al 2022).…”

Section: Quantifying Patchy Indirect Effects Of Predation At Local An...mentioning

confidence: 99%

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Patchy indirect effects of predation: predators contribute to landscape heterogeneity and ecosystem function via localized pathways

Johnson‐Bice,

Gable,

Roth

et al. 2023

Oikos

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Predators are widely recognized for their irreplaceable roles in influencing the abundance and traits of lower trophic levels. Predators also have irreplaceable roles in shaping community interactions and ecological processes via highly localized pathways (i.e. effects with well‐defined and measurable spatio–temporal boundaries), irrespective of their influence on prey density or behavior. We synthesized empirical and theoretical research describing how predators – particularly medium‐ and large‐sized carnivores – have indirect ecological effects confined to discrete landscape patches, processes we have termed ‘patchy indirect effects (PIEs) of predation'. Predators generate PIEs via three main localized pathways: generating and distributing prey carcasses, creating ecological hotspots by concentrating nutrients derived from prey, and killing ecosystem engineers that create patches. In each pathway, the indirect effects are limited to discrete areas with measurable spatial and temporal boundaries (i.e. patches). Our synthesis reveals the diverse and complex ways that predators indirectly affect other species via patches, ranging from mediating scavenger interactions to influencing parasite/disease transmission risk, and from altering ecosystem biogeochemistry to facilitating local biodiversity. We provide basic guidelines on how these effects can be quantified at the patch and landscape scales, and discuss how predator‐mediated patches ultimately contribute to landscape heterogeneity and ecosystem functioning. Whereas density‐ and trait‐mediated indirect effects of predation generally occur through population‐scale changes, PIEs of predation occur through individual‐ and patch‐level pathways. Our synthesis provides a more holistic view of the functional role of predation in ecosystems by addressing how predators create patchy landscapes via localized pathways, in addition to influencing the abundance and behavior of lower trophic levels.

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<strong></strong>Bidecadal Analysis of Urbanization Effects and Ecosystem Services at Haldwani, Western Himalayas, India

Sahdev,

Yosef,

Rakholia

et al. 2023

Preprint

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The study sheds light on the impact of urbanization on fragile ecosystems such as the western Himalayas. We use Haldwani in Uttarakhand as an example of human encroachment and loss of ecosystem services. Several environmental parameters such as Nighttime light (NTL), Land Surface Temperatures (LSTs), Aerosol Optical Depth (AOD) and forest cover are used based on satellite imagery to allow a bidecadal comparison (between 2000 and 2020) of the status of these parameters for the city based on these parameters shows a decline in ecosystem services. Significant statistical differences for LSTs and AOD (p < 0.001) can be found in the bidecadal comparison. Furthermore, a strong negative correlation was found between LST-NDVI (r = -0.69) and between NTL-NDVI (r = -0.58) in earlier and last decade intervals. In addition, long-term multi-spectral satellite imagery also shows a decline in tree cover in the reserved forest. Therefore, focusing on ecosystem services related to tree cover in reserved forest areas, particularly in the Indian Himalayan Region (IHR) must be part of a broader action plan to address these issues to further protect fragile Himalayan ecosystems.

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A Cosmic View of ‘Tundra Gardens’: Satellite Imagery Provides a Landscape-Scale Perspective of Arctic Fox Ecosystem Engineering

Cited by 3 publications

References 71 publications

Coexistence of two sympatric predators in a transitional ecosystem under constraining environmental conditions: a perspective from space and habitat use

Coexistence of two sympatric predators in a transitional ecosystem under constraining environmental conditions: a perspective from space and habitat use

Patchy indirect effects of predation: predators contribute to landscape heterogeneity and ecosystem function via localized pathways

<strong></strong>Bidecadal Analysis of Urbanization Effects and Ecosystem Services at Haldwani, Western Himalayas, India

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