scholarly journals Grazing pressure versus environmental covariates: Effects on woody and herbaceous plant biodiversity on a limestone mountain in northern Tunisia

2018 ◽  
Author(s):  
David Anthony Kirk ◽  
F. B. Goldsmith
Keyword(s):  
Beta Diversity ◽  
Negative Relationship ◽  
Grazing Intensity ◽  
Woody Species ◽  
Grazing Pressure ◽  
Herbaceous Plant ◽  
Herbaceous Species ◽  
Environmental Covariates ◽  
Herbaceous Legumes ◽  
Before And After

Mediterranean vegetation is characterized by high biodiversity and conservation value and grazing is controversial. We sampled woody and herbaceous plants on a limestone mountain with strong mesic-xeric gradients, ranked grazing pressure (on a scale of 1-4) and asked whether grazing had a significant effect on plant compositional abundance before and after controlling for environmental covariates. For woody species the shift in means among grazing classes was greater than for herbaceous species according to distance-based redundancy analysis (dbRDA). For herbaceous species differences in multivariate dispersion were greater among grazing classes. Both groups showed significant differences among grazing classes in multivariate location (permutational multivariate ANOVA), even after controlling for aspect. After taking into account biophysical covariates, grazing was not significant and the variation unique to grazing was small. According to best models in dbRDA, grazing was significant in two models for woody species, and all models for herbaceous species. For woody species, spatial variables were most important and confounded with grazing while for herbs, altitude, distance to road, slope, rock outcropping were important. Significant effects of grazing were found for forbs, Poaceae, and Geophytes but not woody and herbaceous legumes. We found a negative relationship between grazing intensity and beta diversity for herbs overall and especially Poaceae, but moderate grazing resulted in higher beta diversity for Geophytes and herbaceous legumes. Jebel Ichkeul provides a microcosm of similar conservation and management issues elsewhere in the Mediterranean. Carefully controlled grazing may enhance plant diversity and maintain the characteristics of maquis vegetation.

scholarly journals Grazing pressure versus environmental covariates: Effects on woody and herbaceous plant biodiversity on a limestone mountain in northern Tunisia

2018 ◽  
Author(s):  
David Anthony Kirk ◽  
F. B. Goldsmith
Keyword(s):  
Beta Diversity ◽  
Negative Relationship ◽  
Grazing Intensity ◽  
Woody Species ◽  
Grazing Pressure ◽  
Herbaceous Plant ◽  
Herbaceous Species ◽  
Environmental Covariates ◽  
Herbaceous Legumes ◽  
Before And After

Mediterranean vegetation is characterized by high biodiversity and conservation value and grazing is controversial. We sampled woody and herbaceous plants on a limestone mountain with strong mesic-xeric gradients, ranked grazing pressure (on a scale of 1-4) and asked whether grazing had a significant effect on plant compositional abundance before and after controlling for environmental covariates. For woody species the shift in means among grazing classes was greater than for herbaceous species according to distance-based redundancy analysis (dbRDA). For herbaceous species differences in multivariate dispersion were greater among grazing classes. Both groups showed significant differences among grazing classes in multivariate location (permutational multivariate ANOVA), even after controlling for aspect. After taking into account biophysical covariates, grazing was not significant and the variation unique to grazing was small. According to best models in dbRDA, grazing was significant in two models for woody species, and all models for herbaceous species. For woody species, spatial variables were most important and confounded with grazing while for herbs, altitude, distance to road, slope, rock outcropping were important. Significant effects of grazing were found for forbs, Poaceae, and Geophytes but not woody and herbaceous legumes. We found a negative relationship between grazing intensity and beta diversity for herbs overall and especially Poaceae, but moderate grazing resulted in higher beta diversity for Geophytes and herbaceous legumes. Jebel Ichkeul provides a microcosm of similar conservation and management issues elsewhere in the Mediterranean. Carefully controlled grazing may enhance plant diversity and maintain the characteristics of maquis vegetation.

scholarly journals Grazing effects on woody and herbaceous plant biodiversity on a limestone mountain in northern Tunisia

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7296 ◽  
Author(s):  
David Anthony Kirk ◽  
Katherine Hébert ◽  
Frank Barrie Goldsmith
Keyword(s):  
Community Composition ◽  
Beta Diversity ◽  
Grazing Intensity ◽  
Variance Partitioning ◽  
Grazing Pressure ◽  
Herbaceous Plant ◽  
Before And After ◽  
Mediterranean Maquis ◽  
The Individual ◽  
Herbaceous Community

Mediterranean maquis vegetation is highly biodiverse, but widespread grazing poses a challenge for management and conservation. We sampled woody and herbaceous plants separately on a limestone mountain with strong mesic-xeric gradients in Tunisia’s Parc National de L’Ichkeul, assessed grazing pressure (on a scale of 1–3), and asked whether grazing had a significant effect on plant compositional abundance before and after controlling for environmental covariates. Sites on the more mesic lakeside face of the mountain were most compositionally unique, and forbs contributed most to the herbaceous beta-diversity on the mountain. We used variance partitioning to separate the collective and individual effects of the abiotic environment, grazing, human activity, and space on herbaceous and woody beta-diversity. However, the individual effect of grazing on overall plant community composition was confounded with space, due to the spatially autocorrelated grazing pressure on the mountain. Importantly, we found that herbaceous and woody communities responded differently to increasing levels of grazing intensity: herbaceous beta-diversity was highest between sites with no grazing pressure, while woody beta-diversity peaked under light grazing. Herbaceous community composition was sensitive to any intensity of grazing pressure, and biotic homogenization occured under moderate-to-high grazing pressure. On the other hand, woody community composition remained relatively similar under no to light grazing pressure, but differed under moderate-to-heavy grazing. Using a one-way permutational analysis of variance analysis, we showed that grazing had a significant effect when controlling for abiotic and spatial covariates. Our findings offer insight into the effects of grazing on maquis vegetation at Jebel Ichkeul, acting as a microcosm of similar conservation and management issues elsewhere in the Mediterranean. We suggest that a combination of monitoring and carefully controlled grazing may enhance plant diversity and maintain the region’s biodiverse maquis vegetation, potentially maintaining a key climate refugium for vulnerable endemic species. Importantly, our study provides a useful baseline of the plant assemblages at Jebel Ichkeul with which to compare future vegetation changes.

Influence of Sulfonylurea and Other Herbicides on Selected Woody and Herbaceous Species

Weed Science ◽  
1990 ◽  
Vol 38 (3) ◽  
pp. 249-255 ◽  
Author(s):  
Robert E. Meyer ◽  
Rodney W. Bovey
Keyword(s):  
Plant Cover ◽  
Woody Species ◽  
Herbaceous Plant ◽  
Herbaceous Species ◽  
Grass Cover ◽  
Weed Cover ◽  
Broadleaf Species ◽  
Honey Mesquite

Chlorsulfuron and metsulfuron were effective on Texas whitebrush, killing 70 to 75% of the plants at 0.28 kg ai ha, marginally effective on Macartney rose, killing 15 to 43% of the plants at 1.12 kg ha, but ineffective on honey mesquite and huisache, killing no more than 10% of the plants at 1.12 kg ha. Sulfometuron was ineffective on all woody species at 1.12 kg ai ha. Clopyralid and picloram were effective, killing 70 to 92% of the huisache at 2.24 kg ae ha. Tebuthiuron killed 72% of the Texas whitebrush at 1.12 kg ai ha. Sulfometuron generally reduced herbaceous plant cover the year of application. Chlorsulfuron and metsulfuron often resulted in increased grass cover the year of application. Most herbicides reduced broadleaf weeds the year of application. Woolly croton often was the first prominent broadleaf species to return to areas treated with clopyralid and sulfometuron. Few differences occurred among herbicides in herbaceous weed cover the year following treatment.

scholarly journals Does EO NDVI seasonal metrics capture variations in species composition and biomass due to grazing in semi-arid grassland savannas?

2015 ◽  
Vol 12 (14) ◽  
pp. 4407-4419 ◽  
Author(s):  
J. L. Olsen ◽  
S. Miehe ◽  
P. Ceccato ◽  
R. Fensholt
Keyword(s):  
Time Series ◽  
Species Composition ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Regional Scale ◽  
Grazing Intensity ◽  
Test Site ◽  
Grazing Pressure ◽  
Modis Ndvi ◽  
Coarse Resolution

Abstract. Most regional scale studies of vegetation in the Sahel have been based on Earth observation (EO) imagery due to the limited number of sites providing continuous and long term in situ meteorological and vegetation measurements. From a long time series of coarse resolution normalized difference vegetation index (NDVI) data a greening of the Sahel since the 1980s has been identified. However, it is poorly understood how commonly applied remote sensing techniques reflect the influence of extensive grazing (and changes in grazing pressure) on natural rangeland vegetation. This paper analyses the time series of Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI metrics by comparing it with data from the Widou Thiengoly test site in northern Senegal. Field data include grazing intensity, end of season standing biomass (ESSB) and species composition from sizeable areas suitable for comparison with moderate – coarse resolution satellite imagery. It is shown that sampling plots excluded from grazing have a different species composition characterized by a longer growth cycle as compared to plots under controlled grazing or communal grazing. Also substantially higher ESSB is observed for grazing exclosures as compared to grazed areas, substantially exceeding the amount of biomass expected to be ingested by livestock for this area. The seasonal integrated NDVI (NDVI small integral; capturing only the signal inherent to the growing season recurrent vegetation), derived using absolute thresholds to estimate start and end of growing seasons, is identified as the metric most strongly related to ESSB for all grazing regimes. However plot-pixel comparisons demonstrate how the NDVI/ESSB relationship changes due to grazing-induced variation in annual plant species composition and the NDVI values for grazed plots are only slightly lower than the values observed for the ungrazed plots. Hence, average ESSB in ungrazed plots since 2000 was 0.93 t ha−1, compared to 0.51 t ha−1 for plots subjected to controlled grazing and 0.49 t ha−1 for communally grazed plots, but the average integrated NDVI values for the same period were 1.56, 1.49, and 1.45 for ungrazed, controlled and communal, respectively, i.e. a much smaller difference. This indicates that a grazing-induced development towards less ESSB and shorter-cycled annual plants with reduced ability to turn additional water in wet years into biomass is not adequately captured by seasonal NDVI metrics.

scholarly journals Improving the Quality of Life of Family Caregivers of People with Alzheimer’s Disease through Virtual Communities of Practice: A Quasiexperimental Study

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Montse Romero-Mas ◽  
Anna Ramon-Aribau ◽  
Dyego Leandro Bezerra de Souza ◽  
Andrew M. Cox ◽  
Beni Gómez-Zúñiga
Keyword(s):  
Quality Of Life ◽  
Communities Of Practice ◽  
Family Caregivers ◽  
Virtual Communities ◽  
Negative Relationship ◽  
Before And After ◽  
Ambiguous Result ◽  
Virtual Communities Of Practice ◽  
The Impact

Caring for a person with dementia burdens family caregivers, and there is a close negative relationship between this burden and their quality of life (QoL). Research suggests that caregivers’ main needs are information and training about the disease and support from others experiencing the same situation, and Internet interventions hold considerable promise for meeting these needs. Virtual communities of practice (VCoPs) are Internet frameworks to share knowledge where members collaborate and achieve a sense of trust in the community. This paper seeks to evaluate the impact of participating in a VCoP (developed through an App) on the QoL of caregivers to people with Alzheimer’s. Results show QoL before and after the intervention changed significantly. The impact of VCoP on caregivers’ overall QoL is moderated by age and relation with the person with Alzheimer’s, specifically those over 65, and spouses. VCoPs allow interaction and knowledge sharing among caregivers which provide them mainly with information and support from peers helping them to meet their needs. Furthermore, caregivers’ QoL did not decrease when their relative deteriorated functionally, which could be due to the participation in VCoP. Although we found significant pre- and post differences in caregivers’ health literacy, we must report the ambiguous result that this variable only impacts on QoL’s physical domain. Participants also reported that they had a positive experience because the App was perceived to be a useful tool, because they could manage their own participation and they met peers and felt less lonely. Results suggest that participation in a VCoP impacts positively on caregivers’ QoL.

scholarly journals RESTORATION OF FORMER GRASSLAND IN SOUTH-CENTRAL TEXAS

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Wendy J. Leonard ◽  
O. W. Van Auken
Keyword(s):  
San Antonio ◽  
Plant Cover ◽  
Woody Species ◽  
Bare Soil ◽  
Grass Species ◽  
Herbaceous Plant ◽  
Percent Cover ◽  
Juniperus Ashei ◽  
South Central ◽  
Central Texas

Abstract In the past, grasslands and savannas were common in many areas of south-central Texas, including the San Antonio area. With the advent of European settlers and their livestock, much of this area was converted to agriculture and rangeland. Today, most of San Antonio is developed, but some preservation has occurred. Restored grassland, mechanically cleared of Juniperus ashei (juniper, Ashe juniper) and other woody species in 2013, was examined and compared to adjacent non-cleared woodland. The woodland examined was dominated by Diospyros texana (Texas persimmon) and Juniperus ashei. Richness in the woodland canopy was 15 species. The understory below the canopy had 25 woody species. In the restored grassland area, herbaceous plant cover was 41.8%, woody plant cover 5.8%, bare soil 2.9%, and litter cover 49.5%. Species richness was 71, with 60 herbaceous and 11 woody species (percent cover of each from <0.1–7.1%). The most common species in the restored grassland in descending order were Nassella leucotricha (Texas winter grass), Calyptocarpus vialis (straggler daisy), Carex planostachys (cedar sedge), Sporobolus crypandrus (sand dropseed), D. texana, and Verbesina virginica (frost weed). Several C4 grass species were present with low cover but may increase in abundance over time. Four of the six most common restored grassland species were present below the woodland canopy and 12 woody species were present in the restored grassland as juveniles. Cost of restoration was approximately $38,500 ($7,500 supplies, $31,000 labor).

scholarly journals Disentangling niche theory and beta diversity change

2021 ◽  
Author(s):  
William Godsoe ◽  
Peter J Bellingham ◽  
Elena Moltchanova
Keyword(s):  
Beta Diversity ◽  
Price Equation ◽  
Short Term ◽  
Before And After ◽  
Environmental Requirements ◽  
Habitat Specialists ◽  
Montane Tropical Forest ◽  
Ecological Drift ◽  
Over Time

Beta diversity describes the differences in species composition among communities. Changes in beta diversity over time are thought to be due to selection based on species' niche characteristics. For example, theory predicts that selection that favours habitat specialists will increase beta diversity. In practice, ecologists struggle to predict how beta diversity changes. To remedy this problem, we propose a novel solution that formally measures selection's effects on beta diversity. Using the Price equation, we show how change in beta diversity over time can be partitioned into fundamental mechanisms including selection among species, variable selection among communities, drift, and immigration. A key finding of our approach is that a species' short-term impact on beta diversity cannot be predicted using information on its long-term environmental requirements (i.e. its niche). We illustrate how our approach can be used to partition causes of diversity change in a montane tropical forest before and after an intense hurricane. Previous work in this system highlighted the resistance of habitat specialists and the recruitment of light-demanding species but was unable to quantify the importance of these effects on beta diversity. Using our approach, we show that changes in beta diversity were consistent with ecological drift. We use these results to highlight the opportunities presented by a synthesis of beta diversity and formal models of selection.

scholarly journals Herbaceous plant species diversity in communal agro-pastoral and conservation areas in western Serengeti, Tanzania

2019 ◽  
Vol 7 (5) ◽  
pp. 502-518
Author(s):  
Pius Yoram Kavana ◽  
Anthony Z. Sangeda ◽  
Ephraim J. Mtengeti ◽  
Christopher Mahonge ◽  
John Bukombe ◽  
...  
Keyword(s):  
Species Diversity ◽  
Protected Areas ◽  
Plant Species ◽  
Rural Areas ◽  
Plant Species Diversity ◽  
Livestock Grazing ◽  
Herbaceous Plant ◽  
Herbaceous Species ◽  
Grazing Land ◽  
Grazing Lands

Agro-pastoralism involves the growing of crops and keeping of livestock as a livelihood strategy practiced by communities in rural areas in Africa and is highly dependent on environmental factors including rainfall, soil and vegetation. Agro-pastoral activities, e.g. livestock grazing and land clearing for crop cultivation, impact on environmental condition. This study evaluated the impacts of agro-pastoral activities on herbaceous plant species diversity and abundance in western Serengeti relative to conservation (protected) areas. A vegetation survey was conducted along the grazing gradients of ten 4 km transects from within village lands to protected areas. A total of 123 herbaceous species belonging to 20 families were identified. Higher herbaceous species diversity and richness were found in protected areas than in communal grazing lands. Similarly, the number of perennial herbaceous species was higher in the former than the latter, while occurrence of annuals was higher in the village areas. This observation indicates poor rangeland condition in village communal grazing lands as compared with protected areas. It is obvious that current agro-pastoral activities have contributed to a reduction in herbaceous species diversity in village lands in western Serengeti. However, the array of pasture species, especially desirable perennial species, still present in communal grazing areas, suggests that rejuvenation of these areas is possible. Resting of grazing land is recommended to reverse the trend towards diversity reduction and ensure future availability of feed resources for grazing animals in village lands.

scholarly journals Towards more meaningful scenarios of biodiversity responses to land-use change in Central Asia

2020 ◽  
Vol 20 (3) ◽  
Author(s):  
Johannes Kamp ◽  
Martin Freitag ◽  
Norbert Hölzel
Keyword(s):  
Land Use ◽  
Environmental Change ◽  
Central Asia ◽  
Spatial Data ◽  
Negative Relationship ◽  
Grazing Intensity ◽  
Biodiversity Loss ◽  
Livestock Grazing ◽  
Land Use Patterns ◽  
Use Patterns

Abstract We here respond to Nunez et al. (Reg Environ Chang 20:39, 2020), recently published in Regional Environmental Change. Nunez et al. project biodiversity responses to land-use and climate change in Central Asia. Their projections are based on scenarios of changing socio-economic and environmental conditions for the years 2040, 2070, and 2100. We suggest that the predicted magnitude of biodiversity loss might be biased high, due to four shortfalls in the data used and the methods employed. These are (i) the use of an inadequate measure of “biodiversity intactness,” (ii) a failure to acknowledge for large spatial variation in land-use trends across the five considered Central Asian countries, (iii) the assumption of a strictly linear, negative relationship between livestock grazing intensity and the abundance of animals and plants, and (iv) the extrapolation of grazing-related biodiversity responses into areas of cropland. We conclude that future scenarios of biodiversity response to regional environmental change in Central Asia will benefit from using regional, not global, spatial data on livestock distribution and land-use patterns. The use of extra-regional data on the relationships between biodiversity and land-use or climate should be avoided.

Rangeland condition in relation to environmental variables, grazing intensity and livestock owners' perceptions in semi-arid rangeland in western Iran

2010 ◽  
Vol 32 (4) ◽  
pp. 367 ◽  
Author(s):  
M. Faramarzi ◽  
S. Kesting ◽  
J. Isselstein ◽  
N. Wrage
Keyword(s):  
Environmental Variables ◽  
Management Practices ◽  
Grazing Intensity ◽  
Bare Soil ◽  
Grazing Pressure ◽  
Botanical Composition ◽  
Western Iran ◽  
Range Condition ◽  
Rangeland Condition ◽  
Semi Arid

Rangeland condition has often been assessed in relation to either botanical, edaphic, environmental or management factors. In this investigation, we analysed the interaction of soil and topographic variables, management and range condition against the background of a sociological survey of livestock owners in western Iran to better understand the main influencing factors of rangeland quality in the area. In four grazing areas in Kermanshah differing in grazing pressure, environmental variables and livestock owners’ perceptions on range condition, investigations of botanical composition, soil and topographic variables were carried out on 43 main plots. To evaluate range condition, four factors were considered, namely litter frequency, herbage palatability, amount of biomass, and percentage of bare soil. A questionnaire was used to obtain information about management practices, the perception of livestock owners on range condition and suggested solutions to problems in the different grazing areas. The range condition scores showed that the condition of the sites was either fair or poor. Of the soil and topographic factors, only north-facing aspect explained part of the variation in range condition scores. High grazing intensity was associated with poor range condition. To improve the rangeland condition, measures influencing water availability and a reduction of grazing pressure seem to be more relevant in the study area than fertilisation or seeding.

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