Mammal population densities at a global scale are higher in human‐modified areas

Ecography, Journal Year: 2020, Volume and Issue: 44(1), P. 1 - 13

Published: Sept. 29, 2020

Global landscapes are changing due to human activities with consequences for both biodiversity and ecosystems. For single species, terrestrial mammal population densities have shown mixed responses pressure, increasing decreasing reported in the literature. How impacts of on populations translates into altered global density patterns remains unclear. Here we aim disentangle effect large‐scale using a dataset 6729 estimates 468 species (representing 59% 44% mammalian orders families). We fitted model explain variation based 1‐degree resolution as function footprint index (HFI), proxy direct indirect disturbances, while accounting body mass, trophic level primary productivity (normalized vegetation index; NDVI). found significant positive relationship between HFI, where were higher areas HFI (e.g. agricultural or suburban – no located very high urban areas) compared low wilderness areas). also tested individual components still consistent effect. The relationships remained even across same although variability among was high. Our results indicate shifts modified landscapes, which is combined filtering, increased resources possible reduction competition predation. study provides further evidence that macroecological being by activities, some will benefit from these others be negatively impacted extirpated.

Language: Английский

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Global response of fire activity to late Quaternary grazer extinctions

Science, Journal Year: 2021, Volume and Issue: 374(6571), P. 1145 - 1148

Published: Nov. 25, 2021

Fire activity varies substantially at global scales because of the influence climate, but broad spatiotemporal scales, possible effects herbivory on fire are unknown. Here, we used late Quaternary large-bodied herbivore extinctions as a exclusion experiment to examine responses grassy ecosystem paleofire (through charcoal proxies) continental differences in extinction severity. Grassy increased response extinction, with larger increases continents that suffered largest losses grazers; browser declines had no such effect. These shifts suggest can have Earth system–scale and impacts should be explicitly considered when predicting changes past future activity.

Language: Английский

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Megaherbivore impacts on ecosystem and Earth system functioning: the current state of the science

Ecography, Journal Year: 2021, Volume and Issue: 44(11), P. 1579 - 1594

Published: Sept. 22, 2021

Megaherbivores (adult body mass > 1000 kg) are suggested to disproportionately shape ecosystem and Earth system functioning. We systematically reviewed the empirical basis for this general thesis more specific hypotheses that 1) megaherbivores have larger effects on functioning than their smaller counterparts, 2) is true all extant megaherbivore species 3) vary along environmental gradients. furthermore explored possible biases in our understanding of impacts. found there too few studies quantitatively evaluate or any but African savanna elephant. Following finding, we performed a qualitative vote counting analysis. Our synthesis analysis suggests can elicit strong impacts on, example, vegetation structure biodiversity, elephant promote seed dispersal. were, however, unable whether these disproportionate large herbivores. Although conditions mediate impact, quantified effect rainfall soil fertility impacts, precluding prediction system, particularly under future climates. Moreover, review highlights major taxonomic, thematic geographic effects. Most focused with other functions comparatively neglected. Studies were also biased towards semi‐arid relatively fertile systems, arid, high‐rainfall and/or nutrient‐poor parts megaherbivores' distribution ranges largely unrepresented. findings highlight ecological still limited species, except elephant, current certain areas. further outline detailed, urgently needed avenue research.

Language: Английский

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Correlates of geoxyle diversity in Afrotropical grasslands

Journal of Biogeography, Journal Year: 2022, Volume and Issue: 49(2), P. 339 - 352

Published: Jan. 9, 2022

Abstract Aim Tropical old‐growth grasslands are increasingly acknowledged as biodiverse ecosystems, but they understudied in many aspects. Geoxyle species a key component of these their belowground storage organs and bud banks functionally diverse contribute to the grasslands’ resilience. However, drivers geoxyles’ evolution (belowground) diversity little understood. Thus, we combined analyses on aspects diversity, functionality, ancestry, ecology geoxyles provide first comprehensive understanding this often overlooked growth form. Location Southern hemisphere Africa, particularly Angola part Zambezian phytochorion. Taxon species. Methods We assessed bank types biogeographic origins grass‐dominated vegetation Angolan plateau, covering broad altitudinal, climatic geological range. Geoxyles were sampled extensively at three different sites, yielding 118 taxa about 59% geoxyle flora. Based current distribution Africa below equator, analysed environmental correlates taxonomic, functional context. Results numbers communities differed strongly among showed very similar spectra. evolved multiple lineages originated biomes, unevenly associated with biomes. Furthermore, correlate specific driver combinations. Main conclusions Functional is not directly linked result that contributed differently preadapted can occur under conditions, require seasonal climates, open grassy ecosystems subjected fire, frost likely herbivory. highlight importance emphasize need for further studies understand important complex

Language: Английский

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Rotational grazing with cattle‐free zones supports the coexistence of cattle and wild herbivores in African rangelands

Journal of Applied Ecology, Journal Year: 2023, Volume and Issue: 60(10), P. 2154 - 2166

Published: Aug. 14, 2023

Abstract African wildlife populations are declining at an alarming rate. To stop further population declines and restore ecosystems, more areas for needed. Community‐based conservation with wildlife‐livestock coexistence in the vast rangelands of Africa presents a major opportunity. However, efficacy mixed land‐use remains outstanding question. assess ecological outcomes land‐sharing between regulated livestock herds savannas, we test how rotational cattle grazing affects spatiotemporal dynamics 15 large herbivore species Maasai Mara, Kenya. First, tested wild distributions across Greater Mara Ecosystem (the ~2600 km 2 ) related to density environmental variables using 584,561 observations herbivores (ecosystem scale). In second analysis, 300 subsection 30,583 (landscape Finally, functional traits affect species‐level responses grazing. At ecosystem scale, presence five was positively correlated density, while effects on abundances were species‐dependent both increases decreases. landscape strongly impacted habitat selection herbivores, resulting distinct lag periods which different attracted previously grazed by cattle. These linked traits, body mass herd size explaining 35% interspecific differences. Small medium‐sized select recently cattle, whereas sizes small avoid areas. Synthesis applications : Our results revealed that effect varies considerably among species, suggesting cattle‐wildlife interactions range from facilitation competition. maintain designated livestock‐free zones remain essential, also systems. Rotational systems densities present important opportunity better manage thus improve rangelands.

Language: Английский

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