Extreme drought stress shifts net facilitation to neutral interactions between shrubs and sub‐canopy plants in an arid desert

Zhang, Gefei; Zhao, Wenzhi; Zhou, Hai; Yang, Qingxi; Wang, Xiaofen

doi:10.1111/oik.04630

Cited by 27 publications

(26 citation statements)

References 80 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Thus, G. caespitosa could ameliorate environmental conditions only up to a stress threshold. This finding is similar to previous studies showing that there are limits to facilitation and that, beyond a given threshold of stress, positive interactions are likely to fade (Michalet et al , Holmgren and Scheffer , Qi et al , Zhang et al ).…”

Section: Discussionsupporting

confidence: 91%

Facilitation of an invader by a native habitat‐former increases along interacting gradients of environmental stress

Uyà

Bulleri

Wright

et al. 2020

Ecology

View full text Add to dashboard Cite

Native habitat‐forming species can facilitate invasion by reducing environmental stress or consumer pressure. However, the intensity of one stressor along a local gradient may differ when expanding the scale of observation to encompass major variations in background environmental conditions. In this study, we determined how facilitation of the invasive porcelain crab, Petrolisthes elongatus, by the native tube‐forming serpulid, Galeolaria caespitosa, varied with environmental gradients at local (tidal height) and larger (wave exposure) spatial scales. G. caespitosa constructs a complex calcareous matrix on the underside of intertidal boulders and we predicted that its positive effects on P. elongatus density would increase in intensity with shore height and be stronger at wave‐sheltered than wave‐exposed locations. To test these predictions, we conducted two experiments. First, we determined the effects of serpulid presence (boulders with live or dead serpulid matrix vs. bare boulders) at six shore heights that covered the intertidal distribution of P. elongatus. Second, we determined the effects of serpulid presence (present vs. absent), shore height (high vs. low) and wave exposure (sheltered vs. exposed) on crabs across six locations within the invaded range in northern Tasmania, Australia. In Experiment 1, the presence of serpulids (either dead or alive) enhanced P. elongatus densities at all shore heights, with facilitation intensity (as determined by a relative interaction index; RII) tending to increase with shore height. In Experiment 2, serpulids facilitated P. elongatus across shore heights and wave exposures, although crab densities were lower at high shore levels of wave‐sheltered locations. However, the intensity of crab facilitation by serpulids was greater on wave‐sheltered than on wave‐exposed shores, but only at the high shore level. This study demonstrates that local effects of native habitat‐formers on invasive species are dependent on prevailing environmental conditions at larger spatial scales and that, under more stressful conditions, invaders become increasingly reliant on positive interactions with native habitat‐formers. Increased strength of local‐scale facilitation by native species, dampening broader scale variations in environmental stressors, could enhance the ability of invasive species to establish self‐sustaining populations in the invaded range.

show abstract

Section: Discussionsupporting

confidence: 91%

Facilitation of an invader by a native habitat‐former increases along interacting gradients of environmental stress

Uyà

Bulleri

Wright

et al. 2020

Ecology

View full text Add to dashboard Cite

show abstract

“…Although shrubs can increase nutrient availability through nutrient mobilization from higher soil moisture (Gómez‐Aparicio, Valladares, et al ., 2005), there was no difference between microsites for soil moisture (Appendix ). The other two phytometers species may not have been able to utilize the increased nutrient content in shrub soils because of limitations in soil moisture (Michalet, Brooker, et al ., 2015; Zhang et al ., 2017). There is also evidence that species of the genus Salvia have greater tolerance to drought (Eakes et al ., 1991), suggesting that of the three phytometers, Salvia columbariae may be the most likely to benefit from increased nutrient availability.…”

Section: Discussionmentioning

confidence: 99%

“…Positive interactions could thus become more frequent with aridity because of increasing water stress. Alternatively, facilitation could decrease in frequency at the driest ends of an aridity gradient if shrub species cannot ameliorate extremes in water stress (Michalet, 2006; Le Bagousse‐Pinguet et al ., 2014; Michalet, Maalouf, et al ., 2015; Zhang et al ., 2018). Along aridity gradients, competition among plants can increase in relatively drier conditions because of more limiting water resources (Davis et al ., 1998; Holmgren and Scheffer, 2010).…”

Section: Introductionmentioning

confidence: 99%

Species specificity challenges the predictability of facilitation along a regional desert gradient

Filazzola

Lortie

Westphal

et al. 2020

J Vegetation Science

View full text Add to dashboard Cite

Questions: Deserts ecosystems are threatened by shifts in precipitation patterns from climate change. Positive interactions among plants could buffer desert communities from environmental extremes and resource limitations. However, to improve our ability to predict the response of plant interactions and the plant community to environmental change, we must examine the role of species identity in facilitation. Here, we asked: how do species identity, soil nutrients, and aridity drive positive interactions among plants along a regional gradient of semi-arid to hyper-arid. Location: California, USA. Methods: We selected seven sites located across three deserts in California that cover the geographic range of the benefactor shrub Ephedra californica. In two growing seasons and within 30 pairs of shrub-open microsites at each site, we planted seeds of three annual phytometer species selected for their affinity to areas that are semi-arid, arid, or both. In each microsite, we also surveyed the composition of the annual community and measured soil nutrients. Results: Shrubs facilitated the semi-arid phytometer species, reduced the hyper-arid phytometer species, and had no effect on the species found throughout the arid gradient. Shrub facilitation on community-level biomass of annual species decreased linearly with aridity to neutral interactions at the most arid sites. In the semi-arid sites, shrubs negatively affected community-level species richness and native species abundance, but increased invasive grasses. Conclusions: Idiosyncratic responses of annual plant species to shrub facilitation along an aridity gradient highlight the issue in generalizing plant interactions without considering species-specific differences. Additionally, the effects of shrub facilitation appear to benefit exotic species with competitive traits which can indirectly reduce native species richness in semi-arid ecosystems. Understanding positive interactions in the context of aridity gradients can provide better insights into the expected changes in species composition that will occur as a result of climate change.

show abstract

“…In arid and semiarid environments plant recruitment is water limited [45], and facilitation by nurse shrubs creates safe sites for seedling establishment. Nevertheless, facilitation fails under extremely stressful conditions [46, 47]. We found that senescent plants of the dwarf shrub A .…”

Section: Discussionmentioning

confidence: 99%

Dwarf shrub facilitates seedling recruitment and plant diversity in semiarid grasslands

Gonzalez

Ghermandi

2019

PLoS ONE

View full text Add to dashboard Cite

The facilitation mechanism maintains ecosystem richness by increasing seedling recruitment. Overgrazed grasslands of northwestern Patagonia are invaded by shrubs that could promote the seedling recruitment of forage species. We investigated the role of Acaena splendens shrubs on the maintenance of diversity and its usefulness as a nurse shrub in the recruitment of Festuca pallescens, a grass of high forage value present with a low cover in degraded grasslands. To test the performance of A.splendens as a nurse plant in non-degraded grassland, we recorded the species richness four years inside of A. splendens senescent shrubs and in gaps among dominant tussock grasses. Species were grouped in four functional groups: annual and biannual herbs and grasses, perennial herbs, perennial grasses and shrubs. To test the usefulness of A. splendens in the restoration of degraded grassland, we monitored the seedling emergence and survival of F. pallescens inside A. splendens and in gaps. We related seedling survival to meteorological and microenvironmental conditions. Species richness was higher in Acaena nurse plants than in gaps. The frequency of functional groups, with exception of annual and biannual herbs and grasses, were higher in Acaena than in gaps. Seedling emergence and survival of F. pallescens were higher in Acaena, but the seedlings died in summer in both microsites. Mean maximum temperature was higher and mean minimum humidity lower in gaps than in Acaena during spring. However, the spring-summer season in which we monitored F. pallescens survival, was exceptionally dry and hot, affecting the survival of F. pallescens seedlings. Our results show that A. splendens act as a nurse species increasing the richness in the non-degraded grassland and facilitating the seedling recruitment of an important forage species in the degraded grassland. Nevertheless, the facilitation mechanism will fail in drought conditions, indicating that this restoration tool is limited by climate.

show abstract

Extreme drought stress shifts net facilitation to neutral interactions between shrubs and sub‐canopy plants in an arid desert

Cited by 27 publications

References 80 publications

Facilitation of an invader by a native habitat‐former increases along interacting gradients of environmental stress

Facilitation of an invader by a native habitat‐former increases along interacting gradients of environmental stress

Species specificity challenges the predictability of facilitation along a regional desert gradient

Dwarf shrub facilitates seedling recruitment and plant diversity in semiarid grasslands

Contact Info

Product

Resources

About