Limits...
Increased Primary Production from an Exotic Invader Does Not Subsidize Native Rodents.

Lucero JE, Allen PS, McMillan BR - PLoS ONE (2015)

Bottom Line: Invasive plants have tremendous potential to enrich native food webs by subsidizing net primary productivity.Our experiments demonstrate that increased primary productivity associated with exotic plant invasions may not necessarily subsidize consumers at higher trophic levels.In this context, cheatgrass invasion could disrupt native food webs by providing less-preferred resources that fail to enrich higher trophic levels.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America.

ABSTRACT
Invasive plants have tremendous potential to enrich native food webs by subsidizing net primary productivity. Here, we explored how a potential food subsidy, seeds produced by the aggressive invader cheatgrass (Bromus tectorum), is utilized by an important guild of native consumers--granivorous small mammals--in the Great Basin Desert, USA. In a series of field experiments we examined 1) how cheatgrass invasion affects the density and biomass of seed rain at the ecosystem-level; 2) how seed resources from cheatgrass numerically affect granivorous small mammals; and 3) how the food preferences of native granivores might mediate the trophic integration of cheatgrass seeds. Relative to native productivity, cheatgrass invasion increased the density and biomass of seed rain by over 2000% (P < 0.01) and 3500% (P < 0.01), respectively. However, granivorous small mammals in native communities showed no positive response in abundance, richness, or diversity to experimental additions of cheatgrass seeds over one year. This lack of response correlated with a distinct preference for seeds from native grasses over seeds from cheatgrass. Our experiments demonstrate that increased primary productivity associated with exotic plant invasions may not necessarily subsidize consumers at higher trophic levels. In this context, cheatgrass invasion could disrupt native food webs by providing less-preferred resources that fail to enrich higher trophic levels.

No MeSH data available.


Related in: MedlinePlus

Seed Preference of Native Granivores.Mean ± SE biomass (g) of seeds of ricegrass (Achnatherum hymenoides), bottlebrush squirreltail (Elymus elymoides), and cheatgrass (Bromus tectorum) removed by native granivores during seed preference trials in a Great Basin ecosystem (n = 5). Means with same letter do not significantly differ at P = 0.05.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4526561&req=5

pone.0131564.g003: Seed Preference of Native Granivores.Mean ± SE biomass (g) of seeds of ricegrass (Achnatherum hymenoides), bottlebrush squirreltail (Elymus elymoides), and cheatgrass (Bromus tectorum) removed by native granivores during seed preference trials in a Great Basin ecosystem (n = 5). Means with same letter do not significantly differ at P = 0.05.

Mentions: Granivores more heavily depredated native seeds than cheatgrass seeds, although they did not discriminate between native species. For all transects combined, granivores removed nearly identical masses (P = 0.91) of ricegrass (2.85 g ± 0.03 SE) and squirreltail (2.87 g ± 0.04 SE). By comparison, seed predators removed significantly less (P < 0.01) cheatgrass seeds (2.58 g ± 0.09 SE) (Fig 3). Mixed-models glm analysis confirmed that native granivores removed more native seeds than cheatgrass seeds (P < 0.05) and, importantly, revealed no significant effect of transect location (P = 0.06). In addition, we found no interaction between transect location and provenance (P = 0.09). Thus, native granivores preferred native seeds over cheatgrass seeds at all sites with no evidence of context dependence.


Increased Primary Production from an Exotic Invader Does Not Subsidize Native Rodents.

Lucero JE, Allen PS, McMillan BR - PLoS ONE (2015)

Seed Preference of Native Granivores.Mean ± SE biomass (g) of seeds of ricegrass (Achnatherum hymenoides), bottlebrush squirreltail (Elymus elymoides), and cheatgrass (Bromus tectorum) removed by native granivores during seed preference trials in a Great Basin ecosystem (n = 5). Means with same letter do not significantly differ at P = 0.05.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526561&req=5

pone.0131564.g003: Seed Preference of Native Granivores.Mean ± SE biomass (g) of seeds of ricegrass (Achnatherum hymenoides), bottlebrush squirreltail (Elymus elymoides), and cheatgrass (Bromus tectorum) removed by native granivores during seed preference trials in a Great Basin ecosystem (n = 5). Means with same letter do not significantly differ at P = 0.05.
Mentions: Granivores more heavily depredated native seeds than cheatgrass seeds, although they did not discriminate between native species. For all transects combined, granivores removed nearly identical masses (P = 0.91) of ricegrass (2.85 g ± 0.03 SE) and squirreltail (2.87 g ± 0.04 SE). By comparison, seed predators removed significantly less (P < 0.01) cheatgrass seeds (2.58 g ± 0.09 SE) (Fig 3). Mixed-models glm analysis confirmed that native granivores removed more native seeds than cheatgrass seeds (P < 0.05) and, importantly, revealed no significant effect of transect location (P = 0.06). In addition, we found no interaction between transect location and provenance (P = 0.09). Thus, native granivores preferred native seeds over cheatgrass seeds at all sites with no evidence of context dependence.

Bottom Line: Invasive plants have tremendous potential to enrich native food webs by subsidizing net primary productivity.Our experiments demonstrate that increased primary productivity associated with exotic plant invasions may not necessarily subsidize consumers at higher trophic levels.In this context, cheatgrass invasion could disrupt native food webs by providing less-preferred resources that fail to enrich higher trophic levels.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America.

ABSTRACT
Invasive plants have tremendous potential to enrich native food webs by subsidizing net primary productivity. Here, we explored how a potential food subsidy, seeds produced by the aggressive invader cheatgrass (Bromus tectorum), is utilized by an important guild of native consumers--granivorous small mammals--in the Great Basin Desert, USA. In a series of field experiments we examined 1) how cheatgrass invasion affects the density and biomass of seed rain at the ecosystem-level; 2) how seed resources from cheatgrass numerically affect granivorous small mammals; and 3) how the food preferences of native granivores might mediate the trophic integration of cheatgrass seeds. Relative to native productivity, cheatgrass invasion increased the density and biomass of seed rain by over 2000% (P < 0.01) and 3500% (P < 0.01), respectively. However, granivorous small mammals in native communities showed no positive response in abundance, richness, or diversity to experimental additions of cheatgrass seeds over one year. This lack of response correlated with a distinct preference for seeds from native grasses over seeds from cheatgrass. Our experiments demonstrate that increased primary productivity associated with exotic plant invasions may not necessarily subsidize consumers at higher trophic levels. In this context, cheatgrass invasion could disrupt native food webs by providing less-preferred resources that fail to enrich higher trophic levels.

No MeSH data available.


Related in: MedlinePlus