scholarly journals Examining the assumptions of heterogeneity-based management for promoting plant diversity in a disturbance-prone ecosystem

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6738
Author(s):  
Daniel J. McGlinn ◽  
Michael W. Palmer
Keyword(s):  
Species Composition ◽  
Plant Diversity ◽  
Tallgrass Prairie ◽  
Fine Tuning ◽  
Plant Richness ◽  
Direct Ordination ◽  
Management Approaches ◽  
Landscape Biodiversity ◽  
In Fire ◽  
Grassland Habitats

Background Patch-burn management approaches attempt to increase overall landscape biodiversity by creating a mosaic of habitats using a patchy application of fire and grazing. We tested two assumptions of the patch-burn approach, namely that: (1) fire and grazing drive spatial patch differentiation in community structure and (2) species composition of patches change through time in response to disturbance. Methods We analyzed species cover data on 100 m2 square quadrats from 128 sites located on a 1 × 1 km UTM grid in the grassland habitats of the Tallgrass Prairie Preserve. A total of 20 of these sites were annually sampled for 12 years. We examined how strongly changes in species richness and species composition correlated with changes in management variables relative to independent spatial and temporal drivers using multiple regression and direct ordination, respectively. Results Site effects, probably due to edaphic differences, explained the majority of variation in richness and composition. Interannual variation in fire and grazing management was relatively unimportant relative to inherent site and year drivers with respect to both richness and composition; however, the effects of fire and grazing variables were statistically significant and interpretable, and bison management was positively correlated with plant richness. Conclusions There was some support for the two assumptions of patch-burn management we examined; however, in situ spatial and temporal environmental heterogeneity played a much larger role than management in shaping both plant richness and composition. Our results suggest that fine-tuning the application of fire and grazing may not be critical for maintaining landscape scale plant diversity in disturbance-prone ecosystems.

scholarly journals Examining the foundations of heterogeneity-based management for promoting plant diversity in a disturbance-prone ecosystem

2014 ◽  
Author(s):  
Daniel J McGlinn ◽  
Michael W Palmer
Keyword(s):  
Temporal Variation ◽  
Tallgrass Prairie ◽  
Landscape Heterogeneity ◽  
Variation Partitioning ◽  
Vascular Plant ◽  
Fine Tuning ◽  
Spatial And Temporal Variation ◽  
Management Approach ◽  
Compositional Variation ◽  
In Fire

The conservation of disturbance-prone ecosystems such as rangelands may depend on the spatial and temporal variation in the application of disturbances. Patch-burn management approaches attempt to increase overall landscape biodiversity by creating a mosaic of habitat patches using a patchy application of fire and grazing. Three fundamental assumptions underlay the patch-burn management approach: 1) fire and grazing drive spatial patch differentiation in community structure, 2) species composition of patches diverge through time in response to disturbance, 3) high spatio-temporal variation in fire and grazing results in high compositional variation and thus high landscape-scale diversity. We tested the first two assumptions of the patch-burn approach by comparing the importance of variation in management (changes in fire frequency and grazer species) relative to inherent sources of landscape heterogeneity at the Tallgrass Prairie Preserve in Osage Co., Oklahoma, USA. We sampled 150 square 100 m2 quadrats on a 1 x 1 km UTM grid. We randomly selected 20 of those quadrats to annually resample for 12-years. We recorded visual cover of all vascular plant species rooted within each quadrat. We used variation partitioning within multiple regression and direct ordination frameworks to estimate the relative contribution of classes of variables on species richness and composition respectively. Our results indicate that there was some support for the two assumptions underlying patch-burn management; however, independent spatial and temporal inherent landscape heterogeneity played a much larger role than management in shaping both plant richness and composition. The strength of inherent landscape heterogeneity on the plant community suggests that fine-tuning the application of fire and grazing is not critical for maintaining this community as long as fire and grazing remain part of the system. More generally, the effects of intrinsic spatiotemporal template on biodiversity may dominate even in disturbance-prone ecosystems.

scholarly journals Examining the foundations of heterogeneity-based management for promoting plant diversity in a disturbance-prone ecosystem

2014 ◽  
Author(s):  
Daniel J McGlinn ◽  
Michael W Palmer
Keyword(s):  
Temporal Variation ◽  
Tallgrass Prairie ◽  
Landscape Heterogeneity ◽  
Variation Partitioning ◽  
Vascular Plant ◽  
Fine Tuning ◽  
Spatial And Temporal Variation ◽  
Management Approach ◽  
Compositional Variation ◽  
In Fire

The conservation of disturbance-prone ecosystems such as rangelands may depend on the spatial and temporal variation in the application of disturbances. Patch-burn management approaches attempt to increase overall landscape biodiversity by creating a mosaic of habitat patches using a patchy application of fire and grazing. Three fundamental assumptions underlay the patch-burn management approach: 1) fire and grazing drive spatial patch differentiation in community structure, 2) species composition of patches diverge through time in response to disturbance, 3) high spatio-temporal variation in fire and grazing results in high compositional variation and thus high landscape-scale diversity. We tested the first two assumptions of the patch-burn approach by comparing the importance of variation in management (changes in fire frequency and grazer species) relative to inherent sources of landscape heterogeneity at the Tallgrass Prairie Preserve in Osage Co., Oklahoma, USA. We sampled 150 square 100 m2 quadrats on a 1 x 1 km UTM grid. We randomly selected 20 of those quadrats to annually resample for 12-years. We recorded visual cover of all vascular plant species rooted within each quadrat. We used variation partitioning within multiple regression and direct ordination frameworks to estimate the relative contribution of classes of variables on species richness and composition respectively. Our results indicate that there was some support for the two assumptions underlying patch-burn management; however, independent spatial and temporal inherent landscape heterogeneity played a much larger role than management in shaping both plant richness and composition. The strength of inherent landscape heterogeneity on the plant community suggests that fine-tuning the application of fire and grazing is not critical for maintaining this community as long as fire and grazing remain part of the system. More generally, the effects of intrinsic spatiotemporal template on biodiversity may dominate even in disturbance-prone ecosystems.

scholarly journals Questing ixodid ticks on the vegetation of sable antelope and multi-herbivore enclosures in Thabazimbi

2015 ◽  
Vol 86 (1) ◽  
Author(s):  
André C. Uys ◽  
Ivan G. Horak ◽  
Alan Harrison
Keyword(s):  
Species Composition ◽  
Ixodid Tick ◽  
Tick Control ◽  
Ixodid Ticks ◽  
Seasonal Abundance ◽  
First Year ◽  
Potential Vector ◽  
The Face ◽  
Tick Borne Disease ◽  
Grassland Habitats

This survey of ixodid ticks was the first to compare the species composition and population dynamics of free-living ticks in intensive, sable antelope breeding enclosures, now commonplace in commercial wildlife ranching in South Africa, with those of multi-herbivore enclosures. The species composition, abundance and seasonal abundance of questing ixodid ticks on the vegetation in intensive breeding enclosures for sable antelope (Hippotragus niger), on which strategic tick control is practised, were compared with those of ticks in a multi-species herbivore enclosure surrounding the breeding enclosures in which no tick control is practised. A total of eight ixodid tick species were collected by drag-sampling the woodland and grassland habitats in each enclosure type monthly from July 2011 to July 2013. Rhipicephalus decoloratus, a potential vector of fatal tick-borne disease in sable antelopes, was the most abundant, accounting for 65.4% of the total number of ticks collected in the sable enclosures, whilst representing only 25.4% of number of ticks collected in the multi-species herbivore enclosure. Rhipicephalus decoloratus and R. evertsi evertsi were more abundant than R. appendiculatus (both p < 0.05) and Amblyomma hebraeum (p < 0.001 and p < 0.01, respectively). Rhipicephalus decoloratus larvae were collected throughout the year, with peak collections in November 2012 and October to December 2013 in the sable enclosures; and in April/May 2012 and February/April 2013 in the multi-species herbivore enclosure. More R. decoloratus were recovered in the second year than in the first year in the grassland habitat of the sable enclosures (V = 7.0, p < 0.05) possibly as a result of acaricide resistance. The apparent temporal over-abundance of R. decoloratus in sable antelope breeding enclosures, in the face of strategic tick control, is of concern and requires further investigation.

The effect of drainage height on plant-species composition on a semi-arid green roof system

2021 ◽  
Vol 67 (3-4) ◽  
pp. 149-155
Author(s):  
Har'el Agra ◽  
Hadar Shalom ◽  
Omar Bawab ◽  
Gyongyver J. Kadas ◽  
Leon Blaustein
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Plant Diversity ◽  
Urban Areas ◽  
Green Roof ◽  
Growing Season ◽  
Green Roofs ◽  
Plant Species Composition ◽  
Roof System ◽  
Semi Arid

Abstract Green roofs are expected to contribute to higher biodiversity in urban surroundings. Typically, green roofs have been designed with low plant diversity. However, plant diversity can be enhanced by controlling resource availability and creating distinct niches. Here we hypothesize that by using different drainage heights during the short plant-growing season in a semi-arid green roof system we can create distinct niches and plant communities. Our experiment took place at the University of Haifa, north Israel. We tested three different heights of drainage outlet: 10 cm under the surface of the substrate (Low), 1 cm under the surface of the substrate (Medium) and 3 cm above the surface of the substrate (High) on plant species-composition in green-roof gardens. Grasses cover was higher in High and Medium drainages while forbs cover was higher in Low drainage. Species richness was the highest in Low drainage while diversity indices showed the opposite trend. We conclude that by changing the height of the drainage we can create different niches and change species composition in a short time period of one growing season. This way we can create more diverse green roof communities and enhance biodiversity in urban areas, particularly in semi-arid regions.

Management Practices in Tallgrass Prairie: Large- and Small-Scale Experimental Effects on Species Composition

1993 ◽  
pp. 106-115
Author(s):  
David J. Gibson ◽  
T. R. Seastedt ◽  
John M. Briggs
Keyword(s):  
Species Composition ◽  
Tallgrass Prairie ◽  
Management Practices ◽  
Small Scale

After the fence: vegetation and topsoil condition in grazed, fenced and benchmark eucalypt woodlands of fragmented agricultural landscapes

2011 ◽  
Vol 59 (4) ◽  
pp. 369 ◽  
Author(s):  
Suzanne M. Prober ◽  
Rachel J. Standish ◽  
Georg Wiehl
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Plant Cover ◽  
Agricultural Landscapes ◽  
Livestock Grazing ◽  
Nutrient Concentrations ◽  
Plant Species Composition ◽  
Exotic Plant ◽  
Native Plant ◽  
Plant Richness

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.

Grazing animals as habitat engineers for ground-nesting birds – a review of the issues

2005 ◽  
Vol 2005 ◽  
pp. 68-68
Author(s):  
K. Norris
Keyword(s):  
Species Composition ◽  
Vegetation Structure ◽  
Production Systems ◽  
Bird Species ◽  
Plant Species Composition ◽  
Integral Role ◽  
Avian Biodiversity ◽  
The Uk ◽  
Grassland Habitats ◽  
Ground Nesting

Habitats associated with livestock production systems are important in terms of avian biodiversity in the UK and across Europe. Livestock play an integral role in structuring grassland habitats, which in turn affects their suitability for different ground-nesting bird species. Such habitat engineering is driven mainly by the effect of grazing on plant species composition and vegetation structure. However, ground-nesting birds are also negatively affected by the presence of grazing animals since livestock destroy nests mainly through trampling.

scholarly journals Understory host plant and insect gall diversity changes across topographic habitats differing in nutrient and water stress in the Brazilian Amazon rainforest

2017 ◽  
Vol 47 (3) ◽  
pp. 237-246 ◽  
Author(s):  
Genimar Rebouças JULIÃO ◽  
Emmanuel Duarte ALMADA ◽  
Flávia Regina Capellotto COSTA ◽  
Marco Antônio Alves CARNEIRO ◽  
G. Wilson FERNANDES
Keyword(s):  
Water Stress ◽  
Species Composition ◽  
Host Plant ◽  
Host Plants ◽  
Water Status ◽  
Brazilian Amazon ◽  
Amazon Rainforest ◽  
Terra Firme ◽  
Plant Richness ◽  
Valley Slope

ABSTRACT Topographic gradients in terra firme forests are associated with pronounced changes in soil texture, soil nutrients and distance to the water-table, thereby creating different hydric and nutritional conditions for plants and their associated herbivore community. The aim of this study was to investigate galling species and host plant richness and gall species composition across topographic habitats differing in nutrient and water stress in the Brazilian Amazon rainforest. Nineteen 250 x 3 m plots were randomly sampled in the valley, slope, plateau-slope transition, and plateau habitats in terra firme forests. All individual dicotyledonous plants 1 to 3 meters high were examined for the presence of insect galls. Galling species and host plant richness differed significantly among the studied habitats and were higher in slope habitats (drier habitats), as expected. More humid areas (valleys) showed the lowest richness of galling species, and a lower number of understory host plants. PERMANOVA and PERMDISP results demonstrated that the gall species composition differed significantly in the valley, slope, plateau-slope transition, and plateau areas. However, these structural differences in species composition could be due to unequal dispersion of variability among forest habitats. Our data suggested that spatial heterogeneity, such as a mosaic of local water status and nutrient availability resulting from the topographic conditions, can affect host plants and their associated galling insects.

Seasonal Occurrence of Adult Carabid Beetles (Coleoptera: Carabidae) in West-Central Illinois

2020 ◽  
Vol 55 (3) ◽  
pp. 329-343
Author(s):  
Kenneth W. McCravy ◽  
Jason E. Willand
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Tallgrass Prairie ◽  
Activity Patterns ◽  
Species Abundance ◽  
Abundant Species ◽  
Early Summer ◽  
Carabid Beetles ◽  
West Central ◽  
Central Illinois

Abstract The Carabidae is a diverse family of beetles with many species of interest in conservation and biological control. Carabid beetle adult seasonal activity patterns were studied in a west-central Illinois forest/reconstructed tallgrass prairie matrix over a 2-yr period using pitfall traps. We found a threefold or greater difference in carabid abundance between years. Despite lower abundance, a second year of sampling yielded seven previously undetected species. Abundance and species richness were greatest in May–July and lower in August–October. Relative abundance and species richness were consistent among months between years. Shannon diversity and effective number of species were lowest in June and July. Cyclotrachelus sodalis (LeConte) and Chlaenius platyderus Chaudoir were the two most abundant species, comprising 54.3% of total captures. These species were most abundant in July and June, respectively. Most species showed greatest abundance in spring or early summer, and declined thereafter. Collections of several species were suggestive of bimodal seasonal patterns. Carabid species composition differed significantly among months, but not between years. Our results document seasonal variation in carabid abundance and species composition, and show that sampling throughout the growing season, and multiple sampling years, provide substantial benefits for assessments of carabid diversity in this region.

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