Large mammalian herbivores (megafauna) have experienced extinctions and declines since prehistory. Introduced megafauna have partly counteracted these losses yet are thought to have unusually negative effects compared to native megafauna. Using a meta-analysis of 3,995 plot-scale plant abundance and diversity responses from 221 studies, we found no evidence that megafauna impacts were shaped by nativeness, ‘invasiveness’, ‘feralness’, coevolutionary history, or functional and phylogenetic novelty. Nor was there evidence that introduced megafauna facilitate introduced plants more than native megafauna. Instead, we found strong evidence that functional traits shaped megafauna impacts, with larger-bodied and bulk-feeding megafauna promoting plant diversity. Our work suggests that trait-based ecology provides better insight into interactions between megafauna and plants than concepts of nativeness.

Literature screening and digitization

This meta-analysis was part of a larger effort to understand megafauna impacts on multiple facets of ecosystems (e.g. including soil nutrients, invertebrates, etc). This ensured that the dataset included plant responses that were also measured in studies focused on other response variables (e.g., spider diversity). We searched Web of Science with a string of search terms that included the common names and Latin genera of all terrestrial mammalian megafauna species (common names from HerbiTraits v1.2 (Lundgren et al. 2021)) separated with an ‘OR’ operand, along with the following search terms: “disturb*, graz*, brows*, impact*, effect, affect, disrupt, facilitate, invasi*, ecosystem*, vegetat*, plant*, fauna*, reptil*, amphib*, bird*, rodent*, fish*, invertebrat*, insect*, soil*, carbon, climate, albedo, river*, riparian, desert*, forest*, tundra, decomposition, grassland*, savanna*, chaparral, scrub, shrub, diversity, heterogeneity, extinction, richness, environment, reptile*, ecolog*, hydrolog*, disturbance, density, biodiversity, response*, ecosystem, herbaceous, canopy, germination, cover, pollinator*, tree, nutrient*, understorey, erosion, grass*, vegetation, community, exclosure, competition, effect*, abundance, productivity”. To reduce unrelated results we also included a Web of Science category filter (“WC”) of “ECOLOGY OR ZOOLOGY OR ENVIRONMENTAL SCIENCES OR BIODIVERSITY CONSERVATION OR EVOLUTIONARY BIOLOGY OR GEOGRAPHY PHYSICAL OR REMOTE SENSING OR PLANT SCIENCES OR MULTIDISCIPLINARY SCIENCE OR FORESTRY OR ENTOMOLOGY OR MARINE & FRESHWATER BIOLOGY OR MYCOLOGY OR BIOLOGY OR OCEANOGRAPHY OR ORNITHOLOGY OR BEHAVIORAL SCIENCES OR FISHERIES”. 

The Web of Science review was concluded on the 18th of February 2021 and returned 60,537 studies. We removed duplicate studies using the fuzzy matching algorithm with the function ‘find_duplicates’ in the R package ‘revtools’ (version 0.4.1) (Westgate 2019). After removing duplicates, our final search returned 46,825 studies. Title screening reduced the number of studies to 2,369.

We screened the full text of these studies to only include studies focused on wild megafauna (≥45 kg) and that compared areas with low versus high megafauna densities due to exclosures, policy-driven differences (hunting versus no-hunting in adjacent properties), and differences in introduction or eradication histories (adjacent islands with and without megafauna). Some studies compared areas with and without focal megafauna populations for unknown reasons (e.g., a site with and without horses with no indication of why horses might be absent (Robertson et al. 2019)), which were excluded due to low confidence in the ultimate drivers of observed differences. We excluded all before-after comparisons (e.g., a plot measured prior to exclosure construction and then afterwards) because of the high rates of change in many systems through time (via afforestation, shifts in climate, succession, etc.). Studies that excluded megafauna but also all vertebrates were excluded. Two additional studies reported data from extremely limiting resources (i.e., wetlands in deserts). These were excluded given that such scenarios should be analyzed separately, for which we did not have sufficient sample size. Studies that evaluated the effects of megafauna on transplants or agricultural crops (including plantations) were not digitized. Studies that included an appropriate comparison and reported a central tendency (mean or median), a measurement of error (standard deviation, standard error, variance, etc), and sample size were digitized (n=154). 

This literature list was supplemented by the literature contained in other relevant meta-analyses (Daskin and Pringle 2016, Eldridge et al. 2020) and those encountered in the bibliographies of the studies we digitized. Given the limited number of studies from oceanic islands and regarding widely distributed introduced species (feral pigs, goats) in our initial Web of Science search, we conducted focused Google Scholar searches on July 15th, 2022 with the following terms: “ungulate impacts island*”, “introduced goat impact island*”, “introduced deer impact*”, “feral camel impact*”, “wild OR feral boar OR hog OR swine impact*”, “feral cattle impact*”, “invasive ungulate hawaii OR guam OR new zealand OR pacific island OR new caledonia OR galapagos OR caribbean OR oceanic island” and a Web of Science search on the 22nd of December 2022 using the search string “herbivore* AND plant* AND response*”. This uncovered an additional 482 studies of which 66 studies were fit for inclusion, leading to a total of 221 studies in our final dataset.

We digitized central tendencies (mean, median), error (standard deviation, standard error, interquartile ranges), and sample sizes for each response (diversity, richness, and abundance) in each study. We used ImageJ to extract data from figures  (Schneider et al. 2012). Interquartile ranges and medians (e.g., as extracted from boxplots) were converted to means and standard deviation using the function qe.mean.sd in the package ‘estmeansd’ version 1.0.0 (McGrath et al. 2022). Means and SD/SE were reported by 213 studies (3,846 observations) while 11 studies (149 observations) reported medians and interquartile ranges.

We also digitized relevant covariates from the text, which included time since treatment (e.g., exclosure construction, introduction, eradication, etc), study coordinates (latitude, longitude), megafauna density (standardized to kg per hectare), relative abundance of megafauna (in the case of multispecies megafauna communities and if density was not provided), and the scale of measurement (treated both as area, m², and maximum measurement length, m, to allow the comparison of transects to plots). 

If study coordinates were not exactly provided, we extracted latitude and longitude from the approximate center of each study location in Google Maps. Maximum measurement length was calculated as either the hypotenuse of square/rectangular plots, the length of transects, or the diameter of circular plots. Distributions of megafauna traits, environmental variables (see below), and methodological variables were similar between native and introduced megafauna communities in our final dataset.

We treated measurements of species richness and species diversity (e.g., Shannon Weiner index) as ‘diversity’ responses and density estimates (individual plants per plot), % cover, and biomass as measurements of abundance. Analyzing these responses alone led to similar results. We excluded seed abundance and diversity responses, given that seedbanks can be at disequilibrium from realized plant communities. We included all true plant species, excluding multicellular algae and lichen. 

Effect sizes

Given the presence of negative values and zeros in our dataset, we calculated effect sizes using Hedges’ g, a unitless measure of standardized mean difference between groups. Each effect size was associated with sampling variance calculated from the sample size and standard deviation of each observation. Effect sizes and sampling variances were calculated with the function ‘escalc’ in the R package ‘metafor’ (version 3.5-12) (Viechtbauer 2010).

Megafauna and plant nativeness

Megafauna nativeness was based on study author designations or IUCN range maps (17), if unreported. While many communities had both native and introduced megafauna present, the vast majority of studies only manipulated (excluded) the introduced megafauna, which was possible because of body size differences or through eradication. Only one study manipulated both native and introduced megafauna (Ward‐Jones et al. 2019). Given that the majority of megafauna biomass in this study consisted of introduced megafauna, we classified this study as introduced. Excluding it (only relevant for abundance analyses) led to similar results. The evolutionary exposure of study sites to megafauna (i.e., oceanic islands versus continents and offshore islands) was determined using PHYLACINE v1.2 range maps- (Faurby et al. 2018). We considered New Zealand, which possessed avian megafauna, an oceanic island without coevolutionary history with mammalian megafauna (due to distinctive foraging strategies of avian versus mammalian herbivores). However, counting New Zealand as an offshore island led to similar results. 

The nativeness of collective plant responses was assigned as reported by the authors (1,864 observations from 104 studies). In cases where plant nativeness was unspecified (2,136 observations from 155 studies) we evaluated nativeness based on author-provided flora descriptions of the study site by referring to the Plants of the World Online (POWO n.d.) and the study site location. If introduced plants were described in the study system, we described the study as mixed (and thus excluded it) unless the introduced plants collectively constituted <5% relative abundance (cover, biomass, density), as reported by authors, in which case we counted these systems as ‘native’. From this, we were able to classify an additional 1,718 observations from 113 studies as native (1,499 observations, 97 studies), mixed (218 observations, 15 studies), and introduced (1 observation, 1 study). A final portion of studies did not provide site flora descriptions (418 observations, 42 studies). These studies generally came from large, well-protected landscapes (e.g., Kruger National Park, Arctic tundra). We treated these responses as native. 

The nativeness of individual plant species, relevant only to plant abundance responses, was extracted from the Plants of the World Online (POWO n.d.), as above. Plant taxonomy was standardized with the Taxonomic Name Resolution Service (TNRS) (Boyle et al. 2013).

Coevolutionary history and coevolutionary novelty

The coevolutionary history between megafauna and the biomes to which they have been introduced was determined using biome maps from Olson et al. 2001 (Olson et al. 2001). Introduced megafauna were considered ’coevolved’ with the biome if they would have occurred in the absence of human-caused extinctions and range contractions (e.g., Equus ferus caballus in North America), based on PHYLACINE v1.2’s (Faurby et al. 2018) megafauna distributions in the absence of extinctions and range contractions, or if the megafauna species was native elsewhere within the focal biome, as in the case of megafauna introduced to offshore islands within their native continent. Species-level coevolutionary history between megafauna and individual plant species was determined by comparing plant distributions (POWO n.d.) to PHYLACINE range maps  (Faurby et al. 2018). In cases of multiple introduced megafauna, we based this on the dominant megafauna species, with dominance determined by relative biomass.

Functional and phylogenetic novelty were calculated by identifying coevolved megafauna communities, in the absence of Late Pleistocene extinctions and range contractions, for each study location from PHYLACINE v1.2 range maps (Faurby et al. 2018). Functional novelty was calculated as the Gower distance to the most functionally similar coevolved megafauna. Gower distances were calculated using the function ‘gowdis’ (R package ‘FD’, version 1.0-12.1) (Laliberté et al. 2014) from key megafauna functional traits that determine their effect on the environment (provided by HerbiTraits (Lundgren et al. 2021)). These included body mass (log10 scale), two ordinal dietary traits (graminoid consumption, browse consumption), fermentation type (converted to an ordinal variable describing fermentation efficiency), three non-exclusive binary habitat use variables (aquatic, terrestrial, arboreal), a categorical variable describing limb morphology (plantigrade, digitigrade, unguligrade). Variable weightings followed (Lundgren et al. 2020). Phylogenetic novelty was defined as the cophenetic distance between the introduced megafauna and the most closely related megafauna in the absence of human-caused extinctions and range contractions using the function ‘pd’ (R package ‘ape’ version 5.6-2, (Paradis and Schliep 2019), with the phylogeny provided by PHYLACINE v1.2 (Faurby et al. 2018)). 

For both phylogenetic and functional novelty, we identified the distances between the introduced megafauna and the most similar prehistoric ‘coevolved’ megafauna. This value was relativized by the introduced species’ relative biomass in their community and then averaged across all introduced megafauna. Relative biomass estimates were calculated from relative abundance or absolute density estimates per species, which were reported for 78.4% of data points. 

Environmental covariates

Environmental covariates were extracted for each study location by buffering each study location by 5 km and using the function ‘extract’ from the R package ‘terra’ (version 1.7-6) (Hijmans 2023). Values were averaged across the 5 km buffer. Specifically, we extracted values of net primary productivity (Zhao et al. 2005), maximum annual temperature and precipitation (Fick and Hijmans 2017), and the human footprint index (Venter et al. 2016). The human footprint index was available for both 1993 and 2009. We thus used values closest to the year the data was collected or, if unreported, the year the study was published (n=78 studies). For studies reporting data over multiple years, the year was adjusted for the time when the individual response was collected based on commencement of study and collection interval.

Megafauna community functional traits

To understand how megafauna functional traits influence their effects on plants, we evaluated key megafauna functional traits for all species in our dataset. Given that 80 studies (1,433 observations) manipulated multiple species of megafauna, we analyzed megafauna functional trait summaries at a community level. We did this by multiplying species trait values by their relative biomass in their community (0–1) and then calculating the maximum and mean of these traits (henceforth ‘community-weighted’). Mean trait values reflect overall community tendencies, while the possibility that ecological outcomes may be shaped more by extremes (while accounting for relative biomass) is captured by maximum trait values.

Traits were extracted from HerbiTraits (Lundgren et al. 2021) and included body mass, proportion of megafauna biomass with hindgut fermentation (which has distinct effects on ecosystems relative to foregut fermentation, (Alexander 1993)), and dietary preference for graminoids (grasses and allies). Note that while our meta-analysis focused on megafauna ≥45 kg, some studies excluded smaller herbivores as well. These herbivores were included in trait summaries if ≥10 kg in mass, for which trait data was available.

Browse and graminoid (grass and allies) consumption are the two primary axes of dietary differentiation in herbivores. Browse and graminoid consumption were available from HerbiTraits as two non-exclusive variables ranging from 0 (avoided) to 3 (highly preferred). To synthesize these variables into a single measure, we relativized each species’ graminoid consumption value by multiplying it by their relative biomass (0-1) within their community. We then divided this value by the sum of relativized browse and graminoid consumption.  This variable was used in conjunction with the plant growth form of each response, categorized as forb, woody, or graminoid. Species-level plant growth forms were derived from the World Checklist of Vascular Plants and from the ‘growthform’ package (Zanne et al. 2015). 

Muzzle widths were extracted from (Pérez–Barbería and Gordon 2001, Mendoza et al. 2002). Species-level muzzle widths were absent for 42 species of 114 herbivore species in our dataset (36.8%). We used genus-level averages for the 25 of these species for which genus-level data was available. A remaining 17 species without genus-level estimates were minor members (median 13% relative biomass) of speciose herbivore communities in 40 observations (4 studies). For these observations, we excluded these particular species, calculating muzzle width summaries with the other species present only. Elephants (Loxodonta africana and Elephas maximus), on the other hand, were important components (by biomass) of 154 data points (10 studies). Muzzle width is a poor proxy for dietary selectivity in elephants since these animals use their trunk to forage and can both be selective and consume large quantities of biomass. We thus assigned elephants the same muzzle width as black rhinos (Diceros bicornis) because of their similar body mass and diet. The final dataset included community-weighted muzzle width estimates for all but 56 abundance responses (1.7%) and 13 diversity responses (1.7%), which were excluded from analysis.

Finally, we assigned each megafauna into functional groups to evaluate whether functional group richness shaped megafauna impacts. Functional groups were based on combinations of body mass bins (10–45 kg, 45–100 kg, 100–1,000 kg, ≥1,000 kg), dietary guilds (browser, mixed feeder, grazer), and fermentation type (foregut, hindgut, and simple gut). 

References

• Alejandro, L., R. A. Distel, and S. M. Zalba. 2010. Large herbivore grazing and non-native plant invasions in montane grasslands of central Argentina. Natural Areas Journal 30:148–155.
• Alexander, R. M. 1993. The relative merits of foregut and hindgut fermentation. Journal of zoology 231:391–401.
• Allen, R. B., I. J. Payton, and J. E. Knowlton. 1984. Effects of ungulates on structure and species composition in the Urewera forests as shown by exclosures. New Zealand journal of ecology:119–130.
• Anderson, T. M., M. E. Ritchie, and S. J. McNaughton. 2007. Rainfall and soils modify plant community response to grazing in Serengeti National Park. Ecology 88:1191–1201.
• Anujan, K., J. Ratnam, and M. Sankaran. 2022. Chronic browsing by an introduced mammalian herbivore in a tropical island alters species composition and functional traits of forest understory plant communities. Biotropica 54:1248–1258.
• Asnani, K. M. 2003. Regeneration of woodland vegetation after deer browsing in Sharon Woods Metro Park, Franklin County, Ohio. The Ohio State University.
• Augustine, D. J., and D. A. Frank. 2001. Effects of migratory grazers on spatial heterogeneity of soil nitrogen properties in a grassland ecosystem. Ecology 82:3149–3162.
• Augustine, D. J., and S. J. Mcnaughton. 2004. Regulation of shrub dynamics by native browsing ungulates on East African rangeland. The Journal of applied ecology 41:45–58.
• Augustine, D. J., B. J. Wigley, J. Ratnam, S. Kibet, M. Nyangito, and M. Sankaran. 2019. Large herbivores maintain a two‐phase herbaceous vegetation mosaic in a semi‐arid savanna. Ecology and evolution 9:12779–12788.
• Bailey, J. K., and T. G. Whitham. 2002. Interactions among fire, aspen, and elk affect insect diversity: reversal of a community response. Ecology 83:1701–1712.
• Baines, D., R. B. Sage, and M. M. Baines. 1994. The implications of red deer grazing to ground vegetation and invertebrate communities of Scottish native pinewoods. The Journal of applied ecology:776–783.
• Baker, B. W., H. C. Ducharme, D. C. S. Mitchell, T. R. Stanley, and H. R. Peinetti. 2005. Interaction of beaver and elk herbivory reduces standing crop of willow. Ecological applications: a publication of the Ecological Society of America 15:110–118.
• Bakker, E. S., M. E. Ritchie, H. Olff, D. G. Milchunas, and J. M. H. Knops. 2006. Herbivore impact on grassland plant diversity depends on habitat productivity and herbivore size. Ecology letters 9:780–788.
• Barrett, M. A., and P. Stiling. 2006a. Effects of Key deer herbivory on forest communities in the lower Florida Keys. Biological conservation 129:100–108.
• Barrett, M. A., and P. Stiling. 2006b. Key deer impacts on hardwood hammocks near urban areas. The Journal of wildlife management 70:1574–1579.
• Batzli, G. O., and C. E. Dejaco. 2013. White-tailed deer (Odocoileus virginianus) facilitate the development of nonnative grasslands in central Illinois. The American midland naturalist 170:323–334.
• Baur, L. E., K. A. Schoenecker, and M. D. Smith. 2018. Effects of feral horse herds on rangeland plant communities across a precipitation gradient. Western North American naturalist / Brigham Young University 77:526–539.
• Bayne, P., R. Harden, and I. Davies. 2004. Feral goats (Capra hircus L.) in the Macleay River gorge system, north-eastern New South Wales, Australia. I. Impacts on soil erosion. Wildlife research 31:519–525.
• Beck, H., J. W. Snodgrass, and P. Thebpanya. 2013. Long-term exclosure of large terrestrial vertebrates: Implications of defaunation for seedling demographics in the Amazon rainforest. Biological conservation 163:115–121.
• Beguin, J., S. D. Côté, and M. Vellend. 2022. Large herbivores trigger spatiotemporal changes in forest plant diversity. Ecology 103:e3739.
• Bellingham, P. J., and C. N. Allan. 2003. Forest regeneration and the influences of white-tailed deer (Odocoileus virginianus) in cool temperate New Zealand rain forests. Forest ecology and management 175:71–86.
• Bennett, A. 2008. The impacts of sambar (Cervus unicolor) in the Yarra Ranges National Park. Citeseer.
• Bernard, M., V. Boulanger, J.-L. Dupouey, L. Laurent, P. Montpied, X. Morin, J.-F. Picard, and S. Saïd. 2017. Deer browsing promotes Norway spruce at the expense of silver fir in the forest regeneration phase. Forest ecology and management 400:269–277.
• Bloodworth, K. J., M. E. Ritchie, and K. J. Komatsu. 2020. Effects of white‐tailed deer exclusion on the plant community composition of an upland tallgrass prairie ecosystem. Journal of vegetation science: official organ of the International Association for Vegetation Science 31:899–907.
• Bockett, F. K. 1998. Ungulate effects on tawa (Beilschmiedia tawa) forest in Urewera National Park. Department of Conservation.
• Boiko, S., E. Bielinis, Z. Sierota, A. Zawadzka, A. Słupska, M. Nasiadko, and J. Borkowski. 2019. Polish pony changes lower layer biodiversity in old growth scots pine stands. Forests, Trees and Livelihoods 10:417.
• Boulanger, V., J. Dupouey, F. Archaux, V. Badeau, C. Baltzinger, R. Chevalier, E. Corcket, Y. Dumas, F. Forgeard, and A. Mårell. 2018. Ungulates increase forest plant species richness to the benefit of non‐forest specialists. Global change biology 24:e485–e495.
• Bourg, N. A., W. J. McShea, V. Herrmann, C. M. Stewart, and B. Blossey. 2017. Interactive effects of deer exclusion and exotic plant removal on deciduous forest understory communities. AoB plants 9.
• Bowers, M. A. 1993. Influence of herbivorous mammals on an old-field plant community: years 1-4 after disturbance. Oikos :129–141.
• Boyd, C. S., K. W. Davies, and G. H. Collins. 2017. Impacts of feral horse use on herbaceous riparian vegetation within a sagebrush steppe ecosystem. Rangeland Ecology & Management 70:411–417.
• Boyle, B., N. Hopkins, Z. Lu, J. A. Raygoza Garay, D. Mozzherin, T. Rees, N. Matasci, M. L. Narro, W. H. Piel, S. J. McKay, S. Lowry, C. Freeland, R. K. Peet, and B. J. Enquist. 2013. The taxonomic name resolution service: an online tool for automated standardization of plant names. BMC bioinformatics 14:16.
• Bucher, R., J. Rochlitz, N. Wegner, A. Heiß, A. Grebe, D. G. Schabo, and N. Farwig. 2021. Deer exclusion changes vegetation structure and hunting guilds of spiders, but not multitrophic understory biodiversity. Diversity 13:25.
• Buesching, C. D., C. Newman, J. T. Jones, and D. W. Macdonald. 2011. Testing the effects of deer grazing on two woodland rodents, bankvoles and woodmice. Basic and applied ecology 12:207–214.
• Burke, A. 1997. The impact of large herbivores on floral composition and vegetation structure in the Naukluft Mountains, Namibia. Biodiversity & Conservation 6:1203–1217.
• Burkepile, D. E., D. I. Thompson, R. W. S. Fynn, S. E. Koerner, S. Eby, N. Govender, N. Hagenah, N. P. Lemoine, K. J. Matchett, and K. R. Wilcox. 2016. Fire frequency drives habitat selection by a diverse herbivore guild impacting top–down control of plant communities in an African savanna. Oikos 125:1636–1646.
• Burns, C. E., S. L. Collins, and M. D. Smith. 2009. Plant community response to loss of large herbivores: comparing consequences in a South African and a North American grassland. Biodiversity and conservation 18:2327–2342.
• Bush, E. R., C. D. Buesching, E. M. Slade, and D. W. Macdonald. 2012. Woodland recovery after suppression of deer: cascade effects for small mammals, wood mice (Apodemus sylvaticus) and bank voles (Myodes glareolus). PloS one 7:e31404.
• Cadenasso, M. L., S. T. A. Pickett, and P. J. Morin. 2002. Experimental test of the role of mammalian herbivores on old field succession: community structure and seedling survival. The journal of the Torrey Botanical Society:228–237.
• Callan, R., N. P. Nibbelink, T. P. Rooney, J. E. Wiedenhoeft, and A. P. Wydeven. 2013. Recolonizing wolves trigger a trophic cascade in Wisconsin (USA). The Journal of ecology 101:837–845.
• Carrera, R., W. B. Ballard, P. R. Krausman, J. Devos, M. C. Wallace, S. Cunningham, O. J. Alcumbrac, and S. A. Christensen. 2015. Reproduction and nutrition of desert mule deer with and without predation. The Southwestern naturalist 60:285–298.
• Casabon, C., and D. Pothier. 2008. Impact of deer browsing on plant communities in cutover sites on Anticosti Island. Ecoscience 15:389–397.
• Castleberry, S. B., W. M. Ford, K. V. Miller, and W. P. Smith. 2000. Influences of herbivory and canopy opening size on forest regeneration in a southern bottomland hardwood forest. Forest ecology and management 131:57–64.
• Cecil, E. M., M. J. Spasojevic, and J. H. Cushman. 2019. Cascading effects of mammalian herbivores on ground‐dwelling arthropods: Variable responses across arthropod groups, habitats and years. The Journal of animal ecology 88:1319–1331.
• Charles, G. K., L. M. Porensky, C. Riginos, K. E. Veblen, and T. P. Young. 2017. Herbivore effects on productivity vary by guild: cattle increase mean productivity while wildlife reduce variability. Ecological applications: a publication of the Ecological Society of America 27:143–155.
• Chen, J., Q. Wang, M. Li, F. Liu, W. Li, and L. Yin. 2013. Effects of deer disturbance on soil respiration in a subtropical floodplain wetland of the Yangtze River. European journal of soil biology 56:65–71.
• Chollet, S., C. Baltzinger, M. Maillard, and J.-L. Martin. 2021. Deer exclusion unveils abiotic filtering in forest understorey plant assemblages. Annals of botany 128:371–381.
• Chollet, S., S. Padié, S. Stockton, S. Allombert, A. J. Gaston, and J. Martin. 2016. Positive plant and bird diversity response to experimental deer population reduction after decades of uncontrolled browsing. Diversity and Distributions 22:274–287.
• Christopher, C. C., and G. N. Cameron. 2012. Effects of invasive Amur honeysuckle (Lonicera maackii) and white-tailed deer (Odocoileus virginianus) on litter-dwelling arthropod communities. The American midland naturalist 167:256–272.
• Cocquelet, A., A. Mårell, S. Bonthoux, C. Baltzinger, and F. Archaux. 2019. Direct and indirect effects of ungulates on forest birds’ nesting failure? An experimental test with artificial nests. Forest ecology and management 437:148–155.
• Cole, R. J., and C. M. Litton. 2014. Vegetation response to removal of non-native feral pigs from Hawaiian tropical montane wet forest. Biological invasions 16:125–140.
• Cole, R. J., C. M. Litton, M. J. Koontz, and R. K. Loh. 2012. Vegetation Recovery 16 Years after Feral Pig Removal from a Wet Hawaiian Forest. Biotropica 44:463–471.
• Collard, A., L. Lapointe, J.-P. Ouellet, M. Crête, A. Lussier, C. Daigle, and S. D. Côté. 2010. Slow responses of understory plants of maple-dominated forests to white-tailed deer experimental exclusion. Forest ecology and management 260:649–662.
• van Coller, H., and F. Siebert. 2020. The impact of herbivore exclusion on forb diversity: Comparing species and functional responses during a drought. African journal of ecology 58:236–250.
• Coughenour, M. B. 1991. Biomass and nitrogen responses to grazing of upland steppe on Yellowstone’s northern winter range. The Journal of applied ecology:71–82.
• Cushman, J. H., L. E. Saunders, and T. K. Refsland. 2020. Long‐term and interactive effects of different mammalian consumers on growth, survival, and recruitment of dominant tree species. Ecology and evolution 10:8801–8814.
• Cushman, J. H., T. A. Tierney, and J. M. Hinds. 2004. Variable effects of feral pig disturbances on native and exotic plants in a California grassland. Ecological applications: a publication of the Ecological Society of America 14:1746–1756.
• Dalgleish, H. J., and D. C. Hartnett. 2009. The effects of fire frequency and grazing on tallgrass prairie productivity and plant composition are mediated through bud bank demography. Plant Ecology 201:411–420.
• Damhoureyeh, S. A., and D. C. Hartnett. 1997. Effects of bison and cattle on growth, reproduction, and abundances of five tallgrass prairie forbs. American journal of botany 84:1719–1728.
• Daskin, J. H., and R. M. Pringle. 2016. Does primary productivity modulate the indirect effects of large herbivores? A global meta-analysis. The Journal of animal ecology 85:857–868.
• deCalesta, D. S. 1994. Effect of white-tailed deer on songbirds within managed forests in Pennsylvania. The Journal of wildlife management:711–718.
• DeGraaf, R. M., W. M. Healy, and R. T. Brooks. 1991. Effects of thinning and deer browsing on breeding birds in New England oak woodlands. Forest ecology and management 41:179–191.
• De Stoppelaire, G. H., T. W. Gillespie, J. C. Brock, and G. A. Tobin. 2004. Use of remote sensing techniques to determine the effects of grazing on vegetation cover and dune elevation at Assateague Island National Seashore: impact of horses. Environmental management 34:642–649.
• De Villalobos, A. E., S. M. Zalba, and D. V. Peláez. 2011. Pinus halepensis invasion in mountain pampean grassland: effects of feral horses grazing on seedling establishment. Environmental research 111:953–959.
• DiTommaso, A., S. H. Morris, J. D. Parker, C. L. Cone, and A. A. Agrawal. 2014. Deer browsing delays succession by altering aboveground vegetation and belowground seed banks. PloS one 9:e91155.
• Donaldson, J. E., C. L. Parr, E. H. Mangena, and S. Archibald. 2020. Droughts decouple African savanna grazers from their preferred forage with consequences for grassland productivity. Ecosystems 23:689–701.
• Dunkell, D. O., G. L. Bruland, C. I. Evensen, and C. M. Litton. 2011. Runoff, Sediment Transport, and Effects of Feral Pig (Sus scrofa) Exclusion in a Forested Hawaiian Watershed1. Pacific science 65:175–194.
• Eldridge, D. J., J. Ding, and S. K. Travers. 2020. Feral horse activity reduces environmental quality in ecosystems globally. Biological conservation 241:108367.
• Eldridge, D. J., J. Ding, and S. K. Travers. 2021. Low‐intensity kangaroo grazing has largely benign effects on soil health. Ecological Management & Restoration 22:58–63.
• Elson, A., and D. C. Hartnett. 2017. Bison increase the growth and reproduction of forbs in tallgrass prairie. The American midland naturalist 178:245–259.
• Ens, E. J., C. Daniels, E. Nelson, J. Roy, and P. Dixon. 2016. Creating multi-functional landscapes: Using exclusion fences to frame feral ungulate management preferences in remote Aboriginal-owned northern Australia. Biological conservation 197:235–246.
• Eschtruth, A. K., and J. J. Battles. 2009. Acceleration of exotic plant invasion in a forested ecosystem by a generalist herbivore. Conservation biology: the journal of the Society for Conservation Biology 23:388–399.
• Falk, J. M., N. M. Schmidt, T. R. Christensen, and L. Ström. 2015. Large herbivore grazing affects the vegetation structure and greenhouse gas balance in a high arctic mire. Environmental research letters: ERL [Web site] 10:045001.
• Faurby, S., M. Davis, R. Ø. Pedersen, S. D. Schowanek, A. Antonelli, and J.-C. Svenning. 2018. PHYLACINE 1.2: The Phylogenetic Atlas of Mammal Macroecology. Ecology 99:2626.
• Fick, S. E., and R. J. Hijmans. 2017. WorldClim 2: new 1-km spatial resolution climate surfaces for global land areas. International Journal of Climatology.
• Flaherty, K. L., J. S. Rentch, W. N. Grafton, and J. T. Anderson. 2018. Timing of white-tailed deer browsing affects wetland plant communities. Plant Ecology 219:313–324.
• Frank, D. A. 2005. The interactive effects of grazing ungulates and aboveground production on grassland diversity. Oecologia 143:629–634.
• Frank, D. A., and P. M. Groffman. 1998. Ungulate vs. landscape control of soil C and N processes in grasslands of Yellowstone National Park. Ecology 79:2229–2241.
• Frank, D. A., R. L. Wallen, E. W. Hamilton III, P. J. White, and J. D. Fridley. 2018. Manipulating the system: How large herbivores control bottom‐up regulation of grasslands. The Journal of ecology 106:434–443.
• Fraser, D., and H. Hristienko. 1983. Effects of moose, Alces alces, on aquatic vegetation in Sibley Provincial Park, Ontario.
• Freedman, B., P. M. Catling, and Z. Lucas. 2011. Effects of feral horses on vegetation of Sable Island, Nova Scotia. Canadian Field-Naturalist 125:200–212.
• Gizicki, Z. S., V. Tamez, A. P. Galanopoulou, P. Avramidis, and J. Foufopoulos. 2018. Long-term effects of feral goats (Capra hircus) on Mediterranean island communities: results from whole island manipulations. Biological invasions 20:1537–1552.
• Goetsch, C., J. Wigg, A. A. Royo, T. Ristau, and W. P. Carson. 2011. Chronic over browsing and biodiversity collapse in a forest understory in Pennsylvania: results from a 60 year-old deer exclusion plot. The journal of the Torrey Botanical Society 138:220–224.
• Goheen, J. R., T. M. Palmer, G. K. Charles, K. M. Helgen, S. N. Kinyua, J. E. Maclean, B. L. Turner, H. S. Young, and R. M. Pringle. 2013. Piecewise disassembly of a large-herbivore community across a rainfall gradient: the UHURU experiment. PloS one 8:e55192.
• Goheen, J. R., T. M. Palmer, F. Keesing, C. Riginos, and T. P. Young. 2010. Large herbivores facilitate savanna tree establishment via diverse and indirect pathways. The Journal of animal ecology 79:372–382.
• Guldemond, R., and R. Van Aarde. 2007. The impact of elephants on plants and their community variables in South Africa’s Maputaland. African journal of ecology 45:327.
• Guldemond, R., and R. Van Aarde. 2010. The influence of tree canopies and elephants on sub‐canopy vegetation in a savannah. African journal of ecology 48:180–189.
• Hanberry, P., B. B. Hanberry, S. Demarais, B. D. Leopold, and J. Fleeman. 2014. Impact on plant communities by white-tailed deer in Mississippi, USA. Plant ecology & diversity 7:541–548.
• Hannaford, J., E. H. Pinn, and A. Diaz. 2006. The impact of sika deer grazing on the vegetation and infauna of Arne saltmarsh. Marine pollution bulletin 53:56–62.
• Hendricks-Franco, L., S. L. Stephens, and W. P. Sousa. 2021. Mammalian herbivory in post-fire chaparral impacts herbaceous composition but not N and C cycling. Journal of Plant Ecology 14:213–228.
• Hensel, M. J. S., B. R. Silliman, E. Hensel, and J. E. K. Byrnes. 2022. Feral hogs control brackish marsh plant communities over time. Ecology 103:e03572.
• Hijmans, R. J. 2023. terra: Spatial Data Analysis.
• Hoffman, M. T., C. F. Madden, K. Erasmus, N. Saayman, and J. C. Botha. 2009. The impact of indigenous ungulate herbivory over five years (2004–2008) on the vegetation of the Little Karoo, South Africa. African Journal of Range & Forage Science 26:169–179.
• Hood, G. A., and S. E. Bayley. 2009. A comparison of riparian plant community response to herbivory by beavers (Castor canadensis) and ungulates in Canada’s boreal mixed-wood forest. Forest ecology and management 258:1979–1989.
• Horsley, S. B., S. L. Stout, and D. S. DeCalesta. 2003. White‐tailed deer impact on the vegetation dynamics of a northern hardwood forest. Ecological applications: a publication of the Ecological Society of America 13:98–118.
• Hothorn, T., F. Bretz, and P. Westfall. 2015. Package multcomp: Simultaneous inference in general parametric models. published online in the CRAN repository.
• Hummel, S. L., H. Campa, and S. R. Winterstein. 2018. Understanding how a keystone herbivore, white-tailed deer impacts wetland vegetation types in southern Michigan. The American midland naturalist 179:51–67.
• Husheer, S. W. 2007. Introduced red deer reduce tree regeneration in Pureora Forest, central North Island, New Zealand. New Zealand journal of ecology:79–87.
• Husheer, S. W., Q. W. Hansen, and S. C. Urlich. 2005. Effects of red deer on tree regeneration and growth in Aorangi Forest, Wairarapa. New Zealand journal of ecology:271–277.
• Ibañez-Alvarez, M., E. Baraza, E. Serrano, A. Romero-Munar, C. Cardona, J. Bartolome, and J. A. Krumins. 2022. Ungulates alter plant cover without consistent effect on soil ecosystem functioning. Agriculture, ecosystems & environment 326:107796.
• Ickes, K., S. J. DeWalt, and S. Appanah. 2001. Effects of native pigs (Sus scrofa) on woody understorey vegetation in a Malaysian lowland rain forest. Journal of tropical ecology 17:191–206.
• IUCN. 2018. IUCN Red List. https://www.iucnredlist.org/.
• Jenkins, L. H., M. A. Jenkins, C. R. Webster, P. A. Zollner, and J. M. Shields. 2014. Herbaceous layer response to 17 years of controlled deer hunting in forested natural areas. Biological conservation 175:119–128.
• Johnson, B. E., and J. H. Cushman. 2007. Influence of a large herbivore reintroduction on plant invasions and community composition in a California grassland. Conservation biology: the journal of the Society for Conservation Biology 21:515–526.
• Kalisz, S., R. B. Spigler, and C. C. Horvitz. 2014. In a long-term experimental demography study, excluding ungulates reversed invader’s explosive population growth rate and restored natives. Proceedings of the National Academy of Sciences 111:4501–4506.
• Kilheffer, C. R., H. B. Underwood, L. Ries, J. Raphael, and D. J. Leopold. 2019. Effects of white-tailed deer (Odocoileus virginianus) exclusion on plant recovery in overwash fans after a severe coastal storm. AoB plants 11:lz059.
• Kolstad, A. L., G. Austrheim, B. J. Graae, E. J. Solberg, G. R. Strimbeck, and J. D. M. Speed. 2019. Moose effects on soil temperatures, tree canopies, and understory vegetation: a path analysis. Ecosphere 10:e02966.
• Lagendijk, G., B. R. Page, and R. Slotow. 2012. Short‐term effects of single species browsing release by different‐sized herbivores on sand forest vegetation community, South Africa. Biotropica 44:63–72.
• Laliberté, E., P. Legendre, and B. Shipley. 2014. FD: measuring functional diversity from multiple traits, and other tools for functional ecology.
• Lamperty, T., K. Zhu, J. R. Poulsen, and A. E. Dunham. 2020. Defaunation of large mammals alters understory vegetation and functional importance of invertebrates in an Afrotropical forest. Biological conservation 241:108329.
• Lessard, J.-P., W. N. Reynolds, W. A. Bunn, M. A. Genung, M. A. Cregger, E. Felker-Quinn, M. N. Barrios-Garcia, M. L. Stevenson, R. M. Lawton, and C. B. Brown. 2012. Equivalence in the strength of deer herbivory on above and below ground communities. Basic and applied ecology 13:59–66.
• Long, R. A., A. Wambua, J. R. Goheen, T. M. Palmer, and R. M. Pringle. 2017. Climatic variation modulates the indirect effects of large herbivores on small‐mammal habitat use. The Journal of animal ecology 86:739–748.
• Lorentzen Kolstad, A., G. Austrheim, E. J. Solberg, L. De Vriendt, and J. D. M. Speed. 2018. Pervasive moose browsing in boreal forests alters successional trajectories by severely suppressing keystone species. Ecosphere 9:e02458.
• Loydi, A. 2019. Effects of grazing exclusion on vegetation and seed bank composition in a mesic mountain grassland in Argentina. Plant ecology & diversity 12:127–138.
• Loydi, A., S. M. Zalba, and R. A. Distel. 2012. Vegetation change in response to grazing exclusion in montane grasslands, Argentina. Plant ecology and evolution 145:313–322.
• Lucas, R. W., R. Salguero-Gómez, D. B. Cobb, B. G. Waring, F. Anderson, W. J. McShea, and B. B. Casper. 2013. White‐tailed deer (Odocoileus virginianus) positively affect the growth of mature northern red oak (Quercus rubra) trees. Ecosphere 4:1–15.
• Lucas, S. 2010. The Effects of Ungulates on Species Composition and Nutrient Cycles in Central NZ Forests. Post-graduate Diploma, University of Otago.
• Lundgren, E. J. (n.d.). MetaMegafauna.
• Lundgren, E. J., D. Ramp, O. S. Middleton, E. I. F. Wooster, E. Kusch, M. Balisi, W. J. Ripple, C. D. Hasselerharm, J. N. Sanchez, M. Mills, and A. D. Wallach. 2022. A novel trophic cascade between cougars and feral donkeys shapes desert wetlands. The Journal of animal ecology.
• Lundgren, E. J., D. Ramp, J. Rowan, O. Middleton, S. D. Schowanek, O. Sanisidro, S. P. Carroll, M. Davis, C. J. Sandom, J.-C. Svenning, and A. D. Wallach. 2020. Introduced herbivores restore Late Pleistocene ecological functions. Proceedings of the National Academy of Sciences of the United States of America 117:7871–7878.
• Lundgren, E. J., S. D. Schowanek, J. Rowan, O. Middleton, R. Ø. Pedersen, A. D. Wallach, D. Ramp, M. Davis, C. J. Sandom, and J.-C. Svenning. 2021. Functional traits of the world’s late Quaternary large-bodied avian and mammalian herbivores. Scientific data 8:17.
• Maillard, M., J.-L. Martin, S. Chollet, C. Catomeris, L. Simon, and S. J. Grayston. 2021. Belowground effects of deer in a temperate forest are time-dependent. Forest ecology and management 493:119228.
• Maron, J. L., and D. E. Pearson. 2011. Vertebrate predators have minimal cascading effects on plant production or seed predation in an intact grassland ecosystem. Ecology letters 14:661–669.
• Martin, J.-L., S. A. Stockton, S. Allombert, and A. J. Gaston. 2010. Top-down and bottom-up consequences of unchecked ungulate browsing on plant and animal diversity in temperate forests: lessons from a deer introduction. Biological invasions 12:353–371.
• Masunga, G. S., S. R. Moe, and B. Pelekekae. 2013. Fire and grazing change herbaceous species composition and reduce beta diversity in the Kalahari sand system. Ecosystems 16:252–268.
• McCauley, D. J., F. Keesing, T. P. Young, B. F. Allan, and R. M. Pringle. 2006. Indirect effects of large herbivores on snakes in an African savanna. Ecology 87:2657–2663.
• McGrath, S., X. Zhao, R. Steele, and A. Benedetti. 2022. estmeansd: Estimating the Sample Mean and Standard Deviation from Commonly Reported Quantiles in Meta-Analysis.
• McInnes, P. F., R. J. Naiman, J. Pastor, and Y. Cohen. 1992. Effects of moose browsing on vegetation and litter of the boreal forest, Isle Royale, Michigan, USA. Ecology 73:2059–2075.
• McMillan, N. A., D. L. Hagan, K. E. Kunkel, and D. S. Jachowski. 2020. Assessing Large Herbivore Management Strategies in the Northern Great Plains Using Rangeland Health Metrics. Natural Areas Journal 40:273–280.
• Meier, M., D. Stöhr, J. Walde, and E. Tasser. 2017. Influence of ungulates on the vegetation composition and diversity of mixed deciduous and coniferous mountain forest in Austria. European journal of wildlife research 63:1–10.
• Mendoza, M., C. M. Janis, and P. Palmqvist. 2002. Characterizing complex craniodental patterns related to feeding behaviour in ungulates: a multivariate approach. Journal of zoology 258:223–246.
• Meyer, J.-Y., T. Laitame, and J.-C. Gaertner. 2019. Short-term recovery of native vegetation and threatened species after restoration of a remnant forest in a small oceanic island of the South Pacific. Plant ecology & diversity 12:75–85.
• Mills, C. H., H. Waudby, G. Finlayson, D. Parker, M. Cameron, and M. Letnic. 2020. Grazing by over-abundant native herbivores jeopardizes conservation goals in semi-arid reserves. Global Ecology and Conservation 24:e01384.
• Minoshima, M., M. B. Takada, N. Agetsuma, and T. Hiura. 2013. Sika deer browsing differentially affects web-building spider densities in high and low productivity forest understories. Ecoscience 20:55–64.
• Mitchell, J., W. Dorney, R. Mayer, and J. McIlroy. 2007. Ecological impacts of feral pig diggings in north Queensland rainforests. Wildlife research 34:603–608.
• Mitchell, J. L. 2002. Ecology and management of feral pigs (Sus scrofa) in rainforests. PhD Thesis, James Cook University.
• Morrison, J. A. 2017. Effects of white-tailed deer and invasive plants on the herb layer of suburban forests. AoB plants 9:lx058.
• Morris, T., and M. Letnic. 2017. Removal of an apex predator initiates a trophic cascade that extends from herbivores to vegetation and the soil nutrient pool. Proceedings of the Royal Society B: Biological Sciences 284:20170111.
• Mosbacher, J. B., A. Michelsen, M. Stelvig, H. Hjermstad-Sollerud, and N. M. Schmidt. 2019. Muskoxen modify plant abundance, phenology, and nitrogen dynamics in a High Arctic fen. Ecosystems 22:1095–1107.
• Munoz, A., R. Bonal, and M. Díaz. 2009. Ungulates, rodents, shrubs: interactions in a diverse Mediterranean ecosystem. Basic and applied ecology 10:151–160.
• Murphy, S. J., and L. S. Comita. 2021. Large mammalian herbivores contribute to conspecific negative density dependence in a temperate forest. The Journal of ecology 109:1194–1209.
• Murray, B. D., C. R. Webster, M. A. Jenkins, M. R. Saunders, and G. S. Haulton. 2016. Ungulate impacts on herbaceous‐layer plant communities in even‐aged and uneven‐aged managed forests. Ecosphere 7:e01378.
• Muthoni, F. K., T. A. Groen, A. K. Skidmore, and P. van Oel. 2014. Ungulate herbivory overrides rainfall impacts on herbaceous regrowth and residual biomass in a key resource area. Journal of arid environments 100:9–17.
• Myster, R. W. 2011. Above-ground vs. below-ground interactive effects of mammalian herbivory on tallgrass prairie plant and soil characteristics. Journal of plant interactions 6:283–290.
• Nafus, M. G., J. A. Savidge, A. A. Yackel Adams, M. T. Christy, and R. N. Reed. 2018. Passive restoration following ungulate removal in a highly disturbed tropical wet forest devoid of native seed dispersers. Restoration Ecology 26:331–337.
• Nakahama, N., K. Uchida, A. Koyama, T. Iwasaki, M. Ozeki, and T. Suka. 2020. Construction of deer fences restores the diversity of butterflies and bumblebees as well as flowering plants in semi-natural grassland. Biodiversity and conservation 29:2201–2215.
• Nuzzo, V., A. Dávalos, and B. Blossey. 2017. Assessing plant community composition fails to capture impacts of white-tailed deer on native and invasive plant species. AoB plants 9.
• Ogada, D. L., M. E. Gadd, R. S. Ostfeld, T. P. Young, and F. Keesing. 2008. Impacts of large herbivorous mammals on bird diversity and abundance in an African savanna. Oecologia 156:387–397.
• Okullo, P., and S. R. Moe. 2012. Large herbivores maintain termite‐caused differences in herbaceous species diversity patterns. Ecology 93:2095–2103.
• Olson, D. M., E. Dinerstein, E. D. Wikramanayake, N. D. Burgess, G. V. N. Powell, E. C. Underwood, I. Itoua, H. E. Strand, J. C. Morrison, C. J. Loucks, T. F. Allnutt, T. H. Ricketts, Y. Kura, J. F. Lamoreux, W. W. Wettengel, P. Hedao, and K. R. Kassem. 2001. Terrestrial Ecoregions of the World: A New Map of Life on Earth. Bioscience 51:933–938.
• Opperman, J. J., and A. M. Merenlender. 2000. Deer herbivory as an ecological constraint to restoration of degraded riparian corridors. Restoration Ecology 8:41–47.
• Page, M. J., J. E. McKenzie, P. M. Bossuyt, I. Boutron, T. C. Hoffmann, C. D. Mulrow, L. Shamseer, J. M. Tetzlaff, E. A. Akl, S. E. Brennan, R. Chou, J. Glanville, J. M. Grimshaw, A. Hróbjartsson, M. M. Lalu, T. Li, E. W. Loder, E. Mayo-Wilson, S. McDonald, L. A. McGuinness, L. A. Stewart, J. Thomas, A. C. Tricco, V. A. Welch, P. Whiting, and D. Moher. 2021. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. Revista espanola de cardiologia 74:790–799.
• Paradis, E., and K. Schliep. 2019. ape 5.0: an environment for modern phylogenetics and evolutionary analyses in R.
• Parker, H. A., J. T. Larkin, D. Heggenstaller, J. Duchamp, M. C. Tyree, C. S. Rushing, E. J. Domoto, and J. L. Larkin. 2020. Evaluating the impacts of white-tailed deer (Odocoileus virginianus) browsing on vegetation in fenced and unfenced timber harvests. Forest ecology and management 473:118326.
• Peebles-Spencer, J. R., D. L. Gorchov, and T. O. Crist. 2017. Effects of an invasive shrub, Lonicera maackii, and a generalist herbivore, white-tailed deer, on forest floor plant community composition. Forest ecology and management 402:204–212.
• Pekin, B. K., M. J. Wisdom, C. G. Parks, B. A. Endress, and B. J. Naylor. 2016. Response of native versus exotic plant guilds to cattle and elk herbivory in forested rangeland. Applied Vegetation Science 19:31–39.
• Pendergast, T. H., IV, S. M. Hanlon, Z. M. Long, A. A. Royo, and W. P. Carson. 2016. The legacy of deer overabundance: long-term delays in herbaceous understory recovery. Canadian journal of forest research. Journal canadien de la recherche forestiere 46:362–369.
• Perea, R., M. Girardello, and A. San Miguel. 2014. Big game or big loss? High deer densities are threatening woody plant diversity and vegetation dynamics. Biodiversity and conservation 23:1303–1318.
• Perea, R., A. López-Sánchez, J. Pallarés, G. G. Gordaliza, I. González-Doncel, L. Gil, and J. Rodríguez-Calcerrada. 2020. Tree recruitment in a drought-and herbivory-stressed oak-beech forest: Implications for future species coexistence. Forest ecology and management 477:118489.
• Pérez–Barbería, F. J., and I. J. Gordon. 2001. Relationships between oral morphology and feeding style in the Ungulata: a phylogenetically controlled evaluation. Proceedings of the Royal Society of London. Series B: Biological Sciences 268:1023–1032.
• Perrin, P. M., D. L. Kelly, and F. J. G. Mitchell. 2006. Long-term deer exclusion in yew-wood and oakwood habitats in southwest Ireland: natural regeneration and stand dynamics. Forest ecology and management 236:356–367.
• Pisanu, P., P. Bayne, R. Harden, and A. Eggert. 2005. Feral goats (Capra hircus L.) in the Macleay River gorge system, north-eastern New South Wales, Australia. II. Impacts on rainforest vegetation. Wildlife research 32:111–119.
• Porensky, L. M., S. F. Bucher, K. E. Veblen, A. C. Treydte, and T. P. Young. 2013. Megaherbivores and cattle alter edge effects around ecosystem hotspots in an African savanna. Journal of arid environments 96:55–63.
• Post, E., and C. Pedersen. 2008. Opposing plant community responses to warming with and without herbivores. Proceedings of the National Academy of Sciences 105:12353–12358.
• POWO. (n.d.). Plants of the World Online. http://www.plantsoftheworldonline.org/.
• Pringle, R. M., T. P. Young, D. I. Rubenstein, and D. J. McCauley. 2007. Herbivore-initiated interaction cascades and their modulation by productivity in an African savanna. Proceedings of the National Academy of Sciences 104:193–197.
• Questad, E. J., A. Uowolo, S. Brooks, R. Fitch, and S. Cordell. 2018. Resource Availability, Propagule Supply, and Effect of Nonnative Ungulate Herbivores on Senecio madagascariensis Invasion1. Pacific science 72:69–79.
• Qvarnemark, L. M., and S. P. Sheldon. 2004. Moose grazing decreases aquatic plant diversity. Journal of freshwater ecology 19:407–410.
• Radloff, F. G. T., L. Mucina, and D. Snyman. 2014. The impact of native large herbivores and fire on the vegetation dynamics in the Cape renosterveld shrublands of South Africa: insights from a six‐yr field experiment. Applied Vegetation Science 17:456–469.
• Ramirez, A. R., R. B. Pratt, A. L. Jacobsen, and S. D. Davis. 2012. Exotic deer diminish post-fire resilience of native shrub communities on Santa Catalina Island, southern California. Plant Ecology 213:1037–1047.
• Ramirez, J. I., P. A. Jansen, J. den Ouden, L. Moktan, N. Herdoiza, and L. Poorter. 2021. Above-and below-ground cascading effects of wild ungulates in temperate forests. Ecosystems 24:153–167.
• Ratajczak, Z., S. L. Collins, J. M. Blair, S. E. Koerner, A. M. Louthan, M. D. Smith, J. H. Taylor, and J. B. Nippert. 2022. Reintroducing bison results in long-running and resilient increases in grassland diversity. Proceedings of the National Academy of Sciences 119:e2210433119.
• Rearick, D., L. Kintz, K. L. Burke, and T. S. Ransom. 2011. Effects of white-tailed deer on the native earthworm, Eisenoides carolinensis, in the southern Appalachian Mountains, USA. Pedobiologia 54:S173–S180.
• Rees, J. D., R. T. Kingsford, and M. Letnic. 2017. In the absence of an apex predator, irruptive herbivores suppress grass seed production: implications for small granivores. Biological conservation 213:13–18.
• Relva, M. A., M. A. Nunez, and D. Simberloff. 2010. Introduced deer reduce native plant cover and facilitate invasion of non-native tree species: evidence for invasional meltdown. Biological invasions 12:303–311.
• Riesch, F., B. Tonn, H. G. Stroh, M. Meißner, N. Balkenhol, and J. Isselstein. 2020. Grazing by wild red deer maintains characteristic vegetation of semi‐natural open habitats: Evidence from a three‐year exclusion experiment. Applied Vegetation Science 23:522–538.
• Risch, A. C., M. Schütz, M. L. Vandegehuchte, W. H. Van Der Putten, H. Duyts, U. Raschein, D. J. Gwiazdowicz, M. D. Busse, D. S. Page-Dumroese, and S. Zimmermann. 2015. Aboveground vertebrate and invertebrate herbivore impact on net N mineralization in subalpine grasslands. Ecology 96:3312–3322.
• Robertson, G., J. Wright, D. Brown, K. Yuen, and D. Tongway. 2019. An assessment of feral horse impacts on treeless drainage lines in the Australian Alps. Ecological Management & Restoration 20:21–30.
• Rogers, G. M. 1991. Kaimanawa feral horses and their environmental impacts. New Zealand journal of ecology:49–64.
• Rojas-Sandoval, J., E. J. Meléndez-Ackerman, J. Fumero-Cabán, M. García-Bermúdez, J. Sustache, S. Aragón, M. Morales-Vargas, G. Olivieri, and D. S. Fernández. 2016. Long-term understory vegetation dynamics and responses to ungulate exclusion in the dry forest of Mona Island.
• Rooney, T. P. 2009. High white-tailed deer densities benefit graminoids and contribute to biotic homogenization of forest ground-layer vegetation. Plant Ecology 202:103–111.
• Rossell, C. R., Jr, B. Gorsira, and S. Patch. 2005. Effects of white-tailed deer on vegetation structure and woody seedling composition in three forest types on the Piedmont Plateau. Forest ecology and management 210:415–424.
• Roy, A., M. Suchocki, L. Gough, and J. R. McLaren. 2020. Above-and belowground responses to long-term herbivore exclusion. Arctic, antarctic, and alpine research 52:109–119.
• Royo, A. A., R. Collins, M. B. Adams, C. Kirschbaum, and W. P. Carson. 2010. Pervasive interactions between ungulate browsers and disturbance regimes promote temperate forest herbaceous diversity. Ecology 91:93–105.
• Royo, A. A., D. W. Kramer, K. V. Miller, N. P. Nibbelink, and S. L. Stout. 2017. Spatio-temporal variation in foodscapes modifies deer browsing impact on vegetation. Landscape ecology 32:2281–2295.
• Rutina, L. P., and S. R. Moe. 2014. Elephant (Loxodonta africana) disturbance to riparian woodland: effects on tree-species richness, diversity and functional redundancy. Ecosystems 17:1384–1396.
• Sakai, M., Y. Natuhara, A. Imanishi, K. Imai, and M. Kato. 2012. Indirect effects of excessive deer browsing through understory vegetation on stream insect assemblages. Population Ecology 54:65–74.
• Saltz, D., H. Schmidt, M. Rowen, A. Karnieli, D. Ward, and I. Schmidt. 1999. Assessing grazing impacts by remote sensing in hyper-arid environments. Rangeland Ecology & Management/Journal of Range Management Archives 52:500–507.
• Sandhage‐Hofmann, A., A. Linstädter, L. Kindermann, S. Angombe, and W. Amelung. 2021. Conservation with elevated elephant densities sequesters carbon in soils despite losses of woody biomass. Global change biology 27:4601–4614.
• Schneider, C. A., W. S. Rasband, and K. W. Eliceiri. 2012. NIH Image to ImageJ: 25 years of image analysis. Nature methods 9:671–675.
• Seliskar, D. M. 2003. The response of Ammophila breviligulata and Spartina patens (Poaceae) to grazing by feral horses on a dynamic mid‐Atlantic barrier island. American journal of botany 90:1038–1044.
• Shibata, E., M. Saito, and M. Tanaka. 2008. Deer-proof fence prevents regeneration of Picea jezoensis var. hondoensis through seed predation by increased woodmouse populations. Journal of Forest Research 13:89–95.
• Siemann, E., J. A. Carrillo, C. A. Gabler, R. Zipp, and W. E. Rogers. 2009. Experimental test of the impacts of feral hogs on forest dynamics and processes in the southeastern US. Forest ecology and management 258:546–553.
• Singer, F. J. 1995. Effects of grazing by ungulates on upland bunchgrass communities of the northern winter range of Yellowstone National Park. Northwest science: official publication of the Northwest Scientific Association 69:191–203.
• Singer, F. J., and M. K. Harter. 1996. Comparative effects of elk herbivory and 1988 fires on northern Yellowstone National Park grasslands. Ecological applications: a publication of the Ecological Society of America 6:185–199.
• Singer, F. J., and R. A. Renkin. 1995. Effects of browsing by native ungulates on the shrubs in big sagebrush communities in Yellowstone National Park. The Great Basin naturalist:201–212.
• Sitters, J., D. M. Kimuyu, T. P. Young, P. Claeys, and H. Olde Venterink. 2020. Negative effects of cattle on soil carbon and nutrient pools reversed by megaherbivores. Nature Sustainability 3:360–366.
• Souza, Y., N. Villar, V. Zipparro, S. Nazareth, and M. Galetti. 2022. Large mammalian herbivores modulate plant growth form diversity in a tropical rainforest. The Journal of ecology 110:845–859.
• Staver, A. C., and W. J. Bond. 2014. Is there a “browse trap”? Dynamics of herbivore impacts on trees and grasses in an African savanna. The Journal of ecology 102:595–602.
• Sterne, J. A. C., A. J. Sutton, J. P. A. Ioannidis, N. Terrin, D. R. Jones, J. Lau, J. Carpenter, G. Rücker, R. M. Harbord, C. H. Schmid, J. Tetzlaff, J. J. Deeks, J. Peters, P. Macaskill, G. Schwarzer, S. Duval, D. G. Altman, D. Moher, and J. P. T. Higgins. 2011. Recommendations for examining and interpreting funnel plot asymmetry in meta-analyses of randomised controlled trials. BMJ 343:d4002.
• Stohlgren, T. J., L. D. Schell, and B. Vanden Heuvel. 1999. How grazing and soil quality affect native and exotic plant diversity in Rocky Mountain grasslands. Ecological applications: a publication of the Ecological Society of America 9:45–64.
• Stuart-Hill, G. C. 1992. Effects of elephants and goats on the Kaffrarian succulent thicket of the eastern Cape, South Africa. The Journal of applied ecology:699–710.
• Suominen, O., K. Danell, and R. Bergström. 1999a. Moose, trees, and ground-living invertebrates: indirect interactions in Swedish pine forests. Oikos :215–226.
• Suominen, O., K. Danell, and J. P. Bryant. 1999b. Indirect effects of mammalian browsers on vegetation and ground-dwelling insects in an Alaskan floodplain. Ecoscience 6:505–510.
• Swain, M. 2021. Indirect impacts of a non-native ungulate browser on soil ecosystem function is variable across soil horizons in the boreal forests of Newfoundland, Canada. Memorial University of Newfoundland.
• Tabuchi, K., D. T. Quiring, L. E. Flaherty, L. L. Pinault, and K. Ozaki. 2011. Bottom-up trophic cascades caused by moose browsing on a natural enemy of a galling insect on balsam fir. Basic and applied ecology 12:523–531.
• Tanentzap, A. J., D. R. Bazely, S. Koh, M. Timciska, E. G. Haggith, T. J. Carleton, and D. A. Coomes. 2011. Seeing the forest for the deer: do reductions in deer-disturbance lead to forest recovery? Biological conservation 144:376–382.
• Tanentzap, A. J., L. E. Burrows, W. G. Lee, G. Nugent, J. M. Maxwell, and D. A. Coomes. 2009. Landscape‐level vegetation recovery from herbivory: progress after four decades of invasive red deer control. Wiley Online Library.
• Taylor, D. L., L.-P. Leung, and I. J. Gordon. 2011. The impact of feral pigs (Sus scrofa) on an Australian lowland tropical rainforest. Wildlife research 38:437–445.
• Tracy, B. F., and D. A. Frank. 1998. Herbivore influence on soil microbial biomass and nitrogen mineralization in a northern grassland ecosystem: Yellowstone National Park. Oecologia:556–562.
• Treydte, A. C., C. C. Grant, and F. Jeltsch. 2009. Tree size and herbivory determine below-canopy grass quality and species composition in savannahs. Biodiversity and conservation 18:3989–4002.
• Uno, H., Y. Inatomi, M. Ueno, and H. Iijima. 2019. Effects of sika deer (Cervus nippon) and dwarf bamboo (Sasa senanensis) on tree seedlings in a cool-temperate mixed forest on Hokkaido Island, Japan. European journal of forest research 138:929–938.
• Vandegehuchte, M. L., M. Schütz, F. De Schaetzen, and A. C. Risch. 2017a. Mammal‐induced trophic cascades in invertebrate food webs are modulated by grazing intensity in subalpine grassland. The Journal of animal ecology 86:1434–1446.
• Vandegehuchte, M. L., W. H. Van Der Putten, H. Duyts, M. Schütz, and A. C. Risch. 2017b. Aboveground mammal and invertebrate exclusions cause consistent changes in soil food webs of two subalpine grassland types, but mechanisms are system‐specific. Oikos 126.
• Van Staalduinen, M. A., H. During, and M. J. A. Werger. 2007. Impact of grazing regime on a Mongolian forest steppe. Applied Vegetation Science 10:299–306.
• Varriano, S., L. H. Lefler, K. Patel, C. Kirksey, A. Turner, and M. D. Moran. 2020. The complementary relationship of bison grazing and arthropod herbivory in structuring a tallgrass prairie community. Rangeland Ecology & Management 73:491–500.
• Veblen, K. E., and T. P. Young. 2010. Contrasting effects of cattle and wildlife on the vegetation development of a savanna landscape mosaic. The Journal of ecology 98:993–1001.
• Venter, O., E. W. Sanderson, A. Magrach, J. R. Allan, J. Beher, K. R. Jones, H. P. Possingham, W. F. Laurance, P. Wood, B. M. Fekete, M. A. Levy, and J. E. M. Watson. 2016. Global terrestrial Human Footprint maps for 1993 and 2009. Scientific data 3:160067.
• Viechtbauer, W. 2010. Conducting meta-analyses in R with the metafor package.
• de Villalobos, A. E., and L. Schwerdt. 2018. Feral horses and alien plants: effects on the structure and function of the Pampean Mountain grasslands (Argentina). Ecoscience 25:49–60.
• de Villalobos, A. E., and L. Schwerdt. 2020. Seasonality of feral horse grazing and invasion of Pinus halepensis in grasslands of the Austral Pampean Mountains (Argentina): management considerations. Biological invasions 22:2941–2955.
• Vinton, M. A., and D. C. Hartnett. 1992. Effects of bison grazing on Andropogon gerardii and Panicum virgatum in burned and unburned tallgrass prairie. Oecologia:374–382.
• Vowles, T., F. Lindwall, A. Ekblad, M. Bahram, B. R. Furneaux, M. Ryberg, and R. G. Björk. 2018. Complex effects of mammalian grazing on extramatrical mycelial biomass in the Scandes forest‐tundra ecotone. Ecology and evolution 8:1019–1030.
• Ward, D., D. Saltz, M. Rowen, and I. Schmidt. 1999. Effects of grazing by re‐introduced Equus hemionus on the vegetation in a Negev desert erosion cirque. Journal of vegetation science: official organ of the International Association for Vegetation Science 10:579–586.
• Ward‐Jones, J., I. Pulsford, R. Thackway, D. Bishwokarma, and D. Freudenberger. 2019. Impacts of feral horses and deer on an endangered woodland of Kosciuszko National Park. Ecological Management & Restoration 20:37–46.
• Ward, J. S., and S. C. Williams. 2020. Influence of deer hunting and residual stand structure on tree regeneration in deciduous forests. Wildlife Society bulletin 44:519–530.
• Webster, C. R., M. A. Jenkins, and J. H. Rock. 2005. Long-term response of spring flora to chronic herbivory and deer exclusion in Great Smoky Mountains National Park, USA. Biological conservation 125:297–307.
• Weller, S. G., R. J. Cabin, D. H. Lorence, S. Perlman, K. Wood, T. Flynn, and A. K. Sakai. 2011. Alien plant invasions, introduced ungulates, and alternative states in a mesic forest in Hawaii. Restoration Ecology 19:671–680.
• Weller, S. G., A. K. Sakai, M. Clark, D. H. Lorence, T. Flynn, W. Kishida, N. Tangalin, and K. Wood. 2018. The effects of introduced ungulates on native and alien plant species in an island ecosystem: Implications for change in a diverse mesic forest in the Hawaiian Islands. Forest ecology and management 409:518–526.
• Werner, P. A. 2005. Impact of feral water buffalo and fire on growth and survival of mature savanna trees: An experimental field study in Kakadu National Park, northern Australia. Austral ecology 30:625–647.
• Werner, P. A., I. D. Cowie, and J. S. Cusack. 2006. Juvenile tree growth and demography in response to feral water buffalo in savannas of northern Australia: an experimental field study in Kakadu National Park. Australian journal of botany 54:283–296.
• Westgate, M. J. 2019. revtools: An R package to support article screening for evidence synthesis.
• Wigley, B. J., D. J. Augustine, C. Coetsee, J. Ratnam, and M. Sankaran. 2020. Grasses continue to trump trees at soil carbon sequestration following herbivore exclusion in a semiarid African savanna. Ecology 101:e03008.
• Wilson, D. J., W. A. Ruscoe, L. E. Burrows, L. M. McElrea, and D. Choquenot. 2006. An experimental study of the impacts of understorey forest vegetation and herbivory by red deer and rodents on seedling establishment and species composition in Waitutu Forest, New Zealand. New Zealand journal of ecology:191–207.
• Wood, G. W., M. T. Mengak, and M. Murphy. 1987. Ecological importance of feral ungulates at Shackleford Banks, North Carolina. The American midland naturalist:236–244.
• Young, T. P., T. M. Palmer, and M. E. Gadd. 2005. Competition and compensation among cattle, zebras, and elephants in a semi-arid savanna in Laikipia, Kenya. Biological conservation 122:351–359.
• Zalba, S. M., and N. C. Cozzani. 2004. The impact of feral horses on grassland bird communities in Argentina. Pages 35–44. Cambridge University Press.
• Zamin, T. J., and P. Grogan. 2013. Caribou exclusion during a population low increases deciduous and evergreen shrub species biomass and nitrogen pools in low A rctic tundra. The Journal of ecology 101:671–683.
• Zanne, A. E., D. C. Tank, W. K. Cornwell, J. M. Eastman, S. A. Smith, R. G. FitzJohn, D. J. McGlinn, B. C. O’Meara, A. T. Moles, P. B. Reich, D. L. Royer, D. E. Soltis, P. F. Stevens, M. Westoby, I. J. Wright, L. Aarssen, R. I. Bertin, A. Calaminus, R. Govaerts, F. Hemmings, M. R. Leishman, J. Oleksyn, P. S. Soltis, N. G. Swenson, L. Warman, and J. M. Beaulieu. 2015. Three keys to the radiation of angiosperms into freezing environments. Nature 521:380.
• Zhao, M., F. A. Heinsch, R. R. Nemani, and S. W. Running. 2005. Improvements of the MODIS terrestrial gross and net primary production global data set. Remote Sensing of the Environment 95:164–176.

R version 4.2.1 as well as a variety of packages, including data.table, metafor, multcomp, ggplot2, broom, tidyr, and dplyr.