scholarly journals Limited evidence for the use of livestock for the conservation management of exotic plant cover

2020 ◽  
Vol 68 (2) ◽  
pp. 137
Author(s):  
David J. Eldridge ◽  
Ian Oliver ◽  
James Val ◽  
Samantha K. Travers

Livestock grazing has been used for conservation management in some situations to reduce exotic plant cover, but supporting empirical evidence is scant. This is particularly true for eastern Australian semiarid woodlands and forests. We surveyed 451 sites across three broad semiarid vegetation communities (cypress pine, black box, red gum) in eastern Australia to examine the effects of recent and longer-term (historic) grazing by livestock on exotic (and native) plant cover. Because our focus was the use of domestic livestock for conservation management, our sites were mostly located in conservation reserves, travelling stock routes and native production forests where domestic grazing is approved via permit. We also included recent grazing by kangaroos and rabbits, which occur widely with livestock across the study sites. Structural equation modelling revealed that recent sheep and cattle grazing was associated with increased exotic plant cover in two of the three communities (cypress pine, black box), and historic grazing was associated with lower exotic (and native) plant cover across all communities. Recent cattle grazing-induced reductions in exotic plant cover in the red gum community resulted from declines in the palatable exotic annual grass Ehrharta longiflora. Higher intensity grazing by rabbits, sheep and cattle in the cypress pine community increased exotic plant cover by suppressing the negative effect of native cover on exotic cover. Higher intensity rabbit grazing reinforced the negative effect of nitrogen on native plant cover, resulting in increases in exotic cover. Overall, we found strong evidence that domestic livestock grazing reduces native plant cover either directly or indirectly in all three communities, but limited evidence that it would be a useful conservation management strategy to reduce exotic plant cover in these communities.

2011 ◽  
Vol 59 (4) ◽  
pp. 369 ◽  
Author(s):  
Suzanne M. Prober ◽  
Rachel J. Standish ◽  
Georg Wiehl

Emerging ecological theory predicts that vegetation changes caused by introduction of livestock grazing may be irreversible after livestock are removed, especially in regions such as Australia that have a short evolutionary exposure to ungulate grazing. Despite this, fencing to exclude livestock grazing is the major tool used to restore vegetation in Australian agricultural landscapes. To characterise site-scale benefits and limitations of livestock exclusion for enhancing biodiversity in forb-rich York gum (Eucalyptus loxophleba Benth. subsp. loxophleba)–jam (Acacia acuminata Benth.) woodlands, we compared 29 fenced woodlands with 29 adjacent grazed woodlands and 11 little-grazed ‘benchmark’ woodlands in the Western Australian wheatbelt. We explored the following two hypotheses: (1) fencing to exclude livestock facilitates recovery of grazed woodlands towards benchmark conditions, and (2) without additional interventions after fencing, complete recovery of grazed woodlands to benchmark conditions is constrained by ecological or other limits. Our first hypothesis was supported for vegetation parameters, with fenced woodlands being more similar to benchmark woodlands in tree recruitment, exotic plant cover, native plant cover, native plant richness and plant species composition than were grazed woodlands. Further, exotic cover decreased and frequency of jam increased with time-since-fencing (2–22 years). However, we found no evidence that fencing led to decline in topsoil nutrient concentrations towards concentrations at benchmark sites. Our second hypothesis was also supported, with higher topsoil nutrient concentrations and exotic plant cover, and lower native plant richness in fenced than in benchmark woodlands, and different plant species composition between fenced and benchmark woodlands. Regression analyses suggested that recovery of native species richness is constrained by exotic species that persist after fencing, which in turn are more persistent at higher topsoil nutrient concentrations. We conclude that fencing to exclude livestock grazing can be valuable for biodiversity conservation. However, consistent with ecological theory, additional interventions are likely to be necessary to achieve some conservation goals or to promote recovery at nutrient-enriched sites.


2018 ◽  
Vol 11 (4) ◽  
pp. 175-180 ◽  
Author(s):  
Christopher L. Zimmerman ◽  
Rebecca R. Shirer ◽  
Jeffrey D. Corbin

AbstractProjects that aim to control invasive species often assume that a reduction of the target species will increase native species abundance. However, reports of the responses of native species following exotic species control are relatively rare. We assessed the recovery of the native community in five tidal wetland locations in which we attempted to eradicate the invasive common reed [Phragmites australis (Cav.) Trin. ex Steud.]. We tested whether 3 yr of treatment were able to eradicate Phragmites and promote recovery of the native plant community. After 3 yr of treatment, Phragmites density declined sharply in all treated stands, though it was not eradicated in any of them. Native plant cover increased significantly in treated areas, and community composition, particularly in smaller stands, converged toward that of uninvaded habitat. Thus, even within the relatively short timescale of the treatments and monitoring, significant progress was made toward achieving the goals of controlling Phragmites infestations and promoting native biodiversity. There was a trend toward greater promise for success in smaller stands than larger stands, as has been observed in other studies. A greater emphasis on monitoring whole-community responses to exotic plant control, across a range of conditions, would enhance our ability to plan and design successful management strategies.


2014 ◽  
Vol 7 (2) ◽  
pp. 257-268 ◽  
Author(s):  
Laura Phillips-Mao ◽  
Diane L. Larson ◽  
Nicholas R. Jordan

AbstractThe degree to which invasive species drive or respond to environmental change has important implications for conservation and invasion management. Often characterized as a driver of change in North American woodlands, the invasive herb garlic mustard may instead respond to declines in native plant cover and diversity. We tested effects of native herb cover, richness, and light availability on garlic mustard invasion in a Minnesota oak woodland. We planted 50 garlic mustard seeds into plots previously planted with 0 to 10 native herb species. We measured garlic mustard seedling establishment, survival to rosette and adult stages, and average (per plant) and total (per plot) biomass and silique production. With the use of structural equation models, we analyzed direct, indirect, and net effects of native cover, richness, and light on successive garlic mustard life stages. Native plant cover had a significant negative effect on all life stages. Species richness had a significant positive effect on native cover, resulting in indirect negative effects on all garlic mustard stages, and net negative effects on adult numbers, total biomass, and silique production. Light had a strong negative effect on garlic mustard seedling establishment and a positive effect on native herb cover, resulting in significant negative net effects on garlic mustard rosette and adult numbers. However, light's net effect on total garlic mustard biomass and silique production was positive; reproductive output was high even in low-light/high-cover conditions. Combined effects of cover, richness, and light suggest that native herbs provide biotic resistance to invasion by responding to increased light availability and suppressing garlic mustard responses, although this resistance may be overwhelmed by high propagule pressure. Garlic mustard invasion may occur, in part, in response to native plant decline. Restoring native herbs and controlling garlic mustard seed production may effectively reduce garlic mustard spread and restore woodland diversity.


2021 ◽  
Author(s):  
Sydney I Glassman ◽  
James WJ Randolph ◽  
Sameer S Saroa ◽  
Joia K Capocchi ◽  
Kendra E Walters ◽  
...  

1. Prescribed fire is often used as a management tool to decrease exotic plant cover and increase native plant cover in grasslands. These changes may also be mediated by fire impacts on soil microbial communities, which drive plant productivity and function. Yet, the ecological effects of prescribed burns compared to wildfires on either plant or soil microbial composition remain unclear. 2. Here, we investigated the impacts of a spring prescribed fire versus a fall wildfire on plant cover and community composition and bacterial and fungal richness, abundance, and composition in a California grassland. We used qPCR of 16S and 18S to assess impacts on bacterial and fungal abundance and Illumina MiSeq of 16S and ITS2 to assess impacts on bacterial and fungal richness and composition. 3. Wildfire had stronger impacts than prescribed fire on microbial communities and both fires had similar impacts on plants with both prescribed and wildfire reducing exotic plant cover but neither reducing exotic plant richness. Fungal richness declined after the wildfire but not prescribed fire, but bacterial richness was unaffected by either. Yet increasing char levels in both fire types resulted in reduced bacterial and fungal biomass, and both fire types slightly altered bacterial and fungal composition. 4. Exotic and native plant diversity differentially affected soil microbial diversity, with native plant diversity leading to increased arbuscular mycorrhizal fungal richness while exotic plant diversity better predicted bacterial richness. However, the remainder of the soil microbial communities were more related to aspects of soil chemistry including cation exchange capacity, organic matter, pH and phosphorous. 5. Synthesis and applications. Understanding the different ecological effects of prescribed fires and wildfires on plant and soil communities are key to enhancing a prevalent management action and to guide potential management opportunities post wildfires. Our coupled plant and soil community sampling allowed us to capture the sensitivity of the fungal community to fire and highlights the importance of potentially incorporating management actions such as soil or fungal amendments to promote this critical community that mediates native plant performance.


2016 ◽  
Vol 28 (10) ◽  
pp. 1587-1588 ◽  
Author(s):  
Donovan T. Maust

The use of psychotropic medication among persons with dementia (PWD) both in nursing home (Wetzels et al., 2011) and community settings (Maust et al., 2016) far exceeds what might be expected based on their limited evidence for benefit (Kales et al., 2015). This relatively high use persists despite years of evidence about the potential harms associated with their use in older adults generally and PWD in particular (e.g. Wang et al., 2001; Schneider et al., 2005). However, the solution to relatively high psychotropic use is not to end all psychotropic use, as there are individual patients for whom use of such medication is appropriate. For example, a policy that defines all antipsychotic use as inappropriate may simply lead to increased use of alternatives with even less evidence of benefit, as suggested by the response to antipsychotics’ black box warning in the United States (Kales et al., 2011).


Web Ecology ◽  
2010 ◽  
Vol 10 (1) ◽  
pp. 27-31 ◽  
Author(s):  
I. Spanos ◽  
Y. Raftoyannis ◽  
P. Platis ◽  
E. Xanthopoulou

Abstract. The effects of management after fire in Pinus halepensis forests were assessed in northern Greece. Seeding, logging and building of log barriers were applied in burned sites and compared to a control site. Two years after treatment application, 70–80% of the ground in all sites was covered with vegetation. Seeding with herbaceous plants did not increase plant cover. Logging and building of log barriers negatively affected herbaceous species but increased woody species. During the first spring after fire, the highest numbers of P. halepensis seedlings were observed in the control site and the lowest number in the logged site. Logging and log barrier building had a negative effect on pine regeneration compared to control and seeding treatments. Woody plant composition was similar in control and seeding sites, with dominance of P. halepensis and Cistus species. A different pattern was observed in the logging and log-barrier sites with a low number of seeders and a high number of resprouter species.


2010 ◽  
Vol 19 (4) ◽  
pp. 490 ◽  
Author(s):  
Erich K. Dodson ◽  
David W. Peterson ◽  
Richy J. Harrod

Slope stabilisation treatments like mulching and seeding are used to increase soil cover and reduce runoff and erosion following severe wildfires, but may also retard native vegetation recovery. We evaluated the effects of seeding and fertilisation on the cover and richness of native and exotic plants and on individual plant species following the 2004 Pot Peak wildfire in Washington State, USA. We applied four seeding and three fertilisation treatments to experimental plots at eight burned sites in spring 2005 and surveyed vegetation during the first two growing seasons after fire. Seeding significantly reduced native non-seeded species richness and cover by the second year. Fertilisation increased native plant cover in both years, but did not affect plant species richness. Seeding and fertilisation significantly increased exotic cover, especially when applied in combination. However, exotic cover and richness were low and treatment effects were greatest in the first year. Seeding suppressed several native plant species, especially disturbance-adapted forbs. Fertilisation, in contrast, favoured several native understorey plant species but reduced tree regeneration. Seeding, even with native species, appears to interfere with the natural recovery of native vegetation whereas fertilisation increases total plant cover, primarily by facilitating native vegetation recovery.


Botany ◽  
2015 ◽  
Vol 93 (9) ◽  
pp. 543-558 ◽  
Author(s):  
Tatyana A. Rand ◽  
Svata M. Louda ◽  
Kate M. Bradley ◽  
Kimberly K. Crider

We examined the type and magnitude of invasive plant (Centaurea stoebe subsp. micranthos (Gugler) Hayek) effects on the demographic parameters of a rare plant (Cirsium pitcheri Torr. & A.Gray), using two seed addition experiments with three treatments in two dune habitats — lakeshore linear dunes and high perched dunes on Lake Michigan, USA. Treatments were near Centaurea stoebe subsp. micranthos, near a native plant, or in the open. Seedling emergence, establishment, and juvenile survivorship were significantly higher on perched dunes, with higher surface soil moisture, than on lakeshore dunes. Treatment effects varied significantly with habitat and life stage. Seedling establishment decreased near Centaurea stoebe subsp. micranthos on lakeshore dunes, but increased near any neighbor on perched dunes. However, juvenile survival was significantly lower near Centaurea stoebe. subsp. micranthos in both habitats. The probability of reaching the adult flowering stage was much lower, and occurred later, for plants near Centaurea stoebe subsp. micranthos, especially on lakeshore dunes. Thus, Centaurea stoebe subsp. micranthos had a strong negative effect on establishment, survival, and flowering of Cirsium pitcheri, but interaction intensity varied with habitat and life stage. The results suggest that coupling seed addition with watering and invasive plant removal could bolster populations of this rare endemic plant.


Author(s):  
Ineta Salmane

Abstract The aim of the present study was to determine the seasonal pattern of two-spotted spider mite Tetranychus urticae on strawberries cultivated in polythene-covered high tunnels in temperate climatic conditions. Various cultivars were used and the effect of modification of plant covering indices on abundance and incidence of these mites was also tested. The number of two-spotted spider mites was relatively low at the beginning of the vegetation season and started to increase when average air temperature rose above 20 to 25 °C. In the experiment two types of tunnels differing in additional plant cover were used. The maximum mite abundance did not significantly vary between varieties in tunnel 1 conditions, but it was significantly lower for variety 'Sonata' in tunnel 2 conditions. Mite numbers significantly declined after strawberry foliage mowing and removal of polythene cover. Mite development was prolonged in tunnel 1, where additional cover of plants was used and higher early season air temperature was recorded in comparison to tunnel 2. It was concluded that increase in early season temperature can increase two-spotted spider mite abundance and have a more negative effect on strawberry plants in respect of foliage damage by mites.


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