Ground vegetation as an indicator of ecological integrity

2009 ◽  
Vol 17 (NA) ◽  
pp. 249-265 ◽  
Author(s):  
Richard LaPaix ◽  
Bill Freedman ◽  
David Patriquin
Keyword(s):  
Plant Species ◽  
Ecological Integrity ◽  
Diversity Indices ◽  
Permanent Plots ◽  
Individual Species ◽  
Ground Vegetation ◽  
Individual Plant ◽  
Ecological Processes ◽  
Assessment Index ◽  
Anthropogenic Stressors

Indicators are being sought for monitoring the ecological integrity of forests and other kinds of ecosystems. Biological measures are commonly used as indicators because of their inherent ecological importance and ability to provide insight into environmental change. Such measures are commonly based on data from sets of permanent plots in which the abundances of plant species are monitored. However, the data may be difficult to interpret, especially if corresponding information on natural and anthropogenic stressors is lacking. In this review, we examine general principles of indicator use and discuss the types of plot-based compositional measures obtained from vegetation that may be most relevant for monitoring ecological integrity. Our focus is on the ground vegetation of forested ecosystems, but the principles discussed are relevant to other vegetation types. Individual plant species, guilds, aliens, diversity indices, Ellenberg indicator values, the floristic quality assessment index, multivariate and multimetric indicators are examined, as well as concepts of threshold changes and the need for reference states. The usefulness of any given approach tends to be highly context specific. In particular, the value of using individual species as indicators is highly dependant on factors such as the character of the floristic community of interest and the types and intensities of anthropogenic stressors. Alien species are considered to be especially valuable indicators of changes in ecological integrity due to their established relationships with anthropogenic stressors, known historical state, relevance to all floristic communities, and ability to cause undesirable changes to biodiversity and ecological processes.

scholarly journals Community level individual-based plant-pollinator networks unveil pollen flow dynamics and plant reproductive success

2021 ◽  
Author(s):  
Alfonso Allen-Perkins ◽  
María Hurtado ◽  
David García-Callejas ◽  
Oscar Godoy ◽  
Ignasi Bartomeus
Keyword(s):  
Reproductive Success ◽  
Plant Species ◽  
Individual Plant ◽  
Ecological Communities ◽  
Ecological Processes ◽  
Individual Level ◽  
Heterospecific Pollen ◽  
Plant Reproductive Success ◽  
The Individual ◽  
Plant Pollinator

Ecological networks are a widely used tool to understand the dynamics of ecological communities in which plants interact with their pollinator counterparts. However, while most mutualistic networks have been defined at the species level, ecological processes, such as pollination, take place at the individual level. This recognition has led to the development of individual-based networks, yet current approaches only account for individuals of a single plant species due to conceptual and mathematical limitations. Here, we introduce a multilayer framework designed to depict the conspecific and heterospecific pollen flows mediated by floral visitors among plant individuals belonging to different species. Pollen transfer is modeled as a transport-like system, where an ensemble of conspecific plant-pollinator “circuits” are coupled through pollinators. With this physical conceptualization of ecological processes, we investigate how the reproductive success of plant individuals is affected by the overall dynamics of the whole multilayer network (macrostructure), as well as by their local position within the network (mesostructure). To illustrate this multiscale analysis, we apply it to a dataset of nine well-resolved individual plant-pollinator interaction networks from annual plant grasslands. Our results show that the resulting individual-based networks are highly modular, with insect visitors effectively connecting individuals of the same and different plant species. We also obtain empirical evidence that network structure is critical for modulating individual plant reproduction. In particular, the mesoscale level is the best descriptor of plant reproductive success, as it integrates the net effect of local heterospecific and conspecific interactions on seed production of a given individual. We provide a simple, but robust set of metrics to scale down network ecology to functioning properties at the individual level, where most ecological processes take place, hence moving forward the description and interpretation of multitrophic communities across scales.

Individual plant species responses to phosphorus and livestock grazing

2011 ◽  
Vol 59 (7) ◽  
pp. 670 ◽  
Author(s):  
J. Dorrough ◽  
S. McIntyre ◽  
M. P. Scroggie
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Native Species ◽  
Livestock Grazing ◽  
Individual Species ◽  
Available Phosphorus ◽  
Individual Plant ◽  
Plant Species Composition ◽  
Native Plant ◽  
Native Plant Species

Livestock grazing and fertilisation are primary management activities that determine variation in plant species composition within grazed temperate grassy ecosystems of Australia. The present paper provides an extensive catalogue of the responses of individual species to grazing and fertilisation that can be used to guide management and restoration in differing situations. A hierarchical model that links plant species identities, simple plant traits and two continuous predictive variables (livestock density and available phosphorus) was used to estimate probability of occurrence of plant species across grazing and phosphorus gradients. Certain species and groups of species, particularly native perennial geophytes, ferns and shrubs, were especially sensitive to increases in each of these management gradients, whereas a small group of exotic plants were most tolerant. In the moderately intensive livestock production landscapes sampled, most native plant species preferred ungrazed areas with low available phosphorus. Many non-native plant species also tolerated or preferred such habitats. Less than 1% of all observed species are predicted to occur at high levels of available phosphorus (75 mg kg–1) and heavy stocking (9 dry sheep equivalents ha–1). There is, however, a suite of native species that persist at moderate livestock densities, but only if soils are not phosphorus-enriched. These data can be used to guide options for restoration including ranking of potential sites or selection of species for reintroduction. In most cases, livestock grazing intensity is thought to be the primary factor influencing plant species composition in grazed woodlands. These data, however, highlight the great importance of fertilisation history in limiting ground-layer plant diversity and determining options for management.

scholarly journals Nitrogen impacts on vascular plants in Britain: an analysis of two national observation networks

2011 ◽  
Vol 8 (4) ◽  
pp. 7441-7474
Author(s):  
P. A. Henrys ◽  
C. J. Stevens ◽  
S. M. Smart ◽  
L. C. Maskell ◽  
K. J. Walker ◽  
...  
Keyword(s):  
Plant Species ◽  
Vascular Plant ◽  
N Deposition ◽  
Additive Models ◽  
Individual Species ◽  
Individual Plant ◽  
Natural Ecosystems ◽  
Sulphur Deposition ◽  
Almost All ◽  
Observation Networks

Abstract. Large areas of the United Kingdom currently have nitrogen (N) deposition at rates which exceed the thresholds above which there is risk of damage to sensitive components of the ecosystem (critical loads), and are predicted to continue to do so. Previous studies have shown that this excess N can be very damaging to semi-natural ecosystems. However, such studies have focussed primarily on the relationship of species richness to nitrogen, possibly missing the risk that increased deposition can have on individual plant species. To address this gap in knowledge, we used data from two national observation networks over Great Britain: the vascular plant database and the Botanical Society of the British Isles local change network to examine the response of individual vascular plant species to nitrogen in acid grasslands, calcareous grasslands and heathlands. Presence absence records of individual species, along with mean Ellenberg scores, within 10 km hectads were modelled against N deposition whilst at the same time controlling for the effects of climate, land use and sulphur deposition using generalised additive models. Ellenberg N showed a significant increase with increasing N deposition in almost all habitats across both surveys. Many individual species showed strong relationships with N deposition and clear negative trends in species prevalence to increasing nitrogen were found in all habitats. Species that showed negative relationships to N showed signs of decline at low levels, far below the current critical load levels.

Rangeland responses to pastoralists' grazing management on a Tibetan steppe grassland, Qinghai Province, China

2016 ◽  
Vol 38 (1) ◽  
pp. 1 ◽  
Author(s):  
Richard B. Harris ◽  
Leah H. Samberg ◽  
Emily T. Yeh ◽  
Andrew T. Smith ◽  
Wang Wenying ◽  
...  
Keyword(s):  
Plant Species ◽  
Temporal Trends ◽  
Winter Season ◽  
Grazing Pressure ◽  
Livestock Grazing ◽  
Western China ◽  
Permanent Plots ◽  
Sheep Grazing ◽  
Qinghai Province ◽  
Preferred Species

Livestock grazing is the principal land use in arid central Asia, and range degradation is considered a serious problem within much of the high-elevation region of western China termed the Qinghai-Tibetan Plateau (QTP). Rangeland degradation on the QTP is variously attributed to poor livestock management, historical-cultural factors, changing land tenure arrangements or socioeconomic systems, climate change, and damage from small mammals. Few studies have examined currently managed pastures using detailed data capable of isolating fine-scale livestock–vegetation interactions. The aim of the study was to understand how differences among livestock (primarily sheep) management strategies of pastoralists during winter affected subsequent rangeland condition and productivity. Plant species composition, annual herbage mass, and indicators of erosion were quantified during four summers (2009–2012) on winter pastures managed by 11 different pastoralists on QTP steppe rangeland in Qinghai Province, China. Data came from repeated-measurements on 317 systematically located permanent plots, as well as pastoralist interviews and the use of GPS-equipped livestock. Relationships between annual weather variation and herbage mass were modelled using an independent set of vegetation measurements obtained from livestock exclosures. Account was taken of inherent site differences among pastures. Annual variation in herbage mass was found to be best fitted by a model containing a negative function of winter-season temperature and a positive function of spring-season temperature. Accounting for annual and site effects, significant differences among pastoralists were found for most response variables, suggesting that individual heterogeneity among management approaches had consequences, even among neighbouring pastoralists. Annual herbage mass of preferred plant species was positively associated, whereas that of unpreferred species was negatively associated, with mean sheep density and intensity of use. However, the proportion of bare soil, an index of erosion, and annual herbage mass of unpreferred forbs were found to have positive relationships with sheep grazing pressure during the preceding winter, whereas live vegetation cover and annual herbage mass of preferred grasses were negatively related. Thus, on a spatial scale, pastoralists responded adaptively to the cover of preferred plant species while not responding to total annual herbage mass. Pastoralists stocked pastures more heavily, and livestock used regions within pastures more intensively, where preferred species had a higher cover. However, where sheep grazing pressure was high, downward temporal trends in the herbage mass of preferred species were exacerbated. Pastures that were stocked at a lower density did not experience the negative trends seen in those with a higher density.

Indirect estimation of the underground standing crop of individual plant species of natural grassland communities

1981 ◽  
Vol 16 (1) ◽  
pp. 95-101 ◽  
Author(s):  
B. K. Behera ◽  
S. R. Misra ◽  
B. N. Misra
Keyword(s):  
Plant Species ◽  
Standing Crop ◽  
Individual Plant ◽  
Indirect Estimation ◽  
Grassland Communities ◽  
Natural Grassland

scholarly journals Interactions Between Individual Plant Species and Soil Nutrient Status in Shortgrass Steppe

Ecology ◽  
1995 ◽  
Vol 76 (4) ◽  
pp. 1116-1133 ◽  
Author(s):  
Mary Ann Vinton ◽  
Ingrid C. Burke
Keyword(s):  
Plant Species ◽  
Soil Nutrient ◽  
Nutrient Status ◽  
Shortgrass Steppe ◽  
Individual Plant ◽  
Soil Nutrient Status

Plant induced spatial distribution of nematodes in a semi-natural grassland

Nematology ◽  
2007 ◽  
Vol 9 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Maria Viketoft
Keyword(s):  
Multivariate Analysis ◽  
Spatial Distribution ◽  
Spatial Structure ◽  
Plant Species ◽  
Trifolium Repens ◽  
Individual Plant ◽  
Nematode Communities ◽  
The Family ◽  
Natural Grassland ◽  
Nematode Fauna

AbstractThis study describes the nematode community in a semi-natural grassland and investigates if certain individual plant species can cause a spatial structure in the nematode fauna. Nematode communities were analysed in soil under Trifolium repens, Festuca ovina and from randomly taken samples. Seventy-nine nematode genera were identified. Some of the species found have not previously been reported from Sweden. Multivariate analysis separated the nematode communities associated with the two selected plant species from each other, and several individual nematode genera differed in abundance between the plant species. Trifolium repens supported greater populations of the plant feeder Tylenchorhynchus and the bacterial feeders Eucephalobus, Chiloplacus, Eumonhystera and Panagrolaimus, but fewer numbers of the bacterial feeder Achromadora. Soil under F. ovina contained more nematodes from the family Alaimidae. A comparison is given with other studies from grassland systems in Sweden.

Using summed individual species models and state-of-the-art modelling techniques to identify threatened plant species hotspots

2009 ◽  
Vol 142 (11) ◽  
pp. 2501-2509 ◽  
Author(s):  
Miia Parviainen ◽  
Mathieu Marmion ◽  
Miska Luoto ◽  
Wilfried Thuiller ◽  
Risto K. Heikkinen
Keyword(s):  
Plant Species ◽  
State Of The Art ◽  
Individual Species ◽  
Threatened Plant ◽  
Threatened Plant Species ◽  
Modelling Techniques

Multispecies and Watershed Approaches to Freshwater Fish Conservation

2019 ◽  
Keyword(s):  
Habitat Diversity ◽  
Reserve Design ◽  
Conservation Strategies ◽  
Individual Species ◽  
Aquatic Communities ◽  
Fish Conservation ◽  
Ecological Processes ◽  
Current Conservation ◽  
The Status ◽  
Effective Conservation

<em>Abstract</em>.—Traditional approaches to fish conservation have focused on the protection of small habitat patches or on individual species at risk of extinction. These strategies have been important yet largely have been too little and too late for widespread protection of aquatic faunas. Such small-scale and reactive approaches also are costly in terms of recovery programs and aggressive in terms of regulatory controls. Further, the linear nature of streams and the networked configuration of drainage systems suggest that a fundamentally different approach to reserve design and protected areas is necessary for effective conservation of freshwater communities when compared to terrestrial systems. Larger-scale, multispecies approaches to native fish conservation offer a more efficient and effective conservation strategy because entire fish communities and the ecological processes that support maintenance of habitat diversity can be sustained before the status of individual species deteriorates to critical levels. Protecting entire communities and watersheds also offers some resistance to climate change impacts, which rapidly are altering flow regimes and disturbance dynamics in aquatic systems. Identification and protection of high-value aquatic communities will provide an important supplement to current conservation strategies during times of increasing threats and future uncertainty.

Impacts of erosion control treatments on native vegetation recovery after severe wildfire in the Eastern Cascades, USA

2010 ◽  
Vol 19 (4) ◽  
pp. 490 ◽  
Author(s):  
Erich K. Dodson ◽  
David W. Peterson ◽  
Richy J. Harrod
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Native Species ◽  
Plant Cover ◽  
Plant Species Richness ◽  
Tree Regeneration ◽  
Vegetation Recovery ◽  
Native Vegetation ◽  
Individual Plant ◽  
Native Plant

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.

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