scholarly journals Effects of reindeer grazing and recovery after cessation of grazing on the ground-dwelling spider assemblage in Finnish Lapland

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7330
Author(s):  
Teemu Saikkonen ◽  
Varpu Vahtera ◽  
Seppo Koponen ◽  
Otso Suominen
Keyword(s):  
Species Richness ◽  
Rangifer Tarandus ◽  
Forest Ecosystems ◽  
Grazing Pressure ◽  
Ground Vegetation ◽  
Total Abundance ◽  
Finnish Lapland ◽  
Species Specific ◽  
The Impact

The effect of reindeer Rangifer tarandus L. grazing on the ground-dwelling spider assemblage in Northern Finland was studied. Changes in species richness, abundance and evenness of spider assemblages were analyzed in relation to changes in vegetation and environmental factors in long term grazed and ungrazed sites as well as sites that had recently switched from grazed to ungrazed and vice versa. Grazing was found to have a significant impact on height and biomass of lichens and other ground vegetation. However, it seemed not to have an impact on the total abundance of spiders. This is likely caused by opposing family and species level responses of spiders to the grazing regime. Lycosid numbers were highest in grazed and linyphiid numbers in ungrazed areas. Lycosidae species richness was highest in ungrazed areas whereas Linyphiidae richness showed no response to grazing. Four Linyphiidae, one Thomisidae and one Lycosidae species showed strong preference for specific treatments. Sites that had recovered from grazing for nine years and the sites that were grazed for the last nine years but were previously ungrazed resembled the long term grazed sites. The results emphasize the importance of reindeer as a modifier of boreal forest ecosystems but the impact of reindeer grazing on spiders seems to be family and species specific. The sites with reversed grazing treatment demonstrate that recovery from strong grazing pressure at these high latitudes is a slow process whereas reindeer can rapidly change the conditions in previously ungrazed sites similar to long term heavily grazed conditions.

scholarly journals Seascape context modifies how fish respond to restored oyster reef structures

2019 ◽  
Vol 76 (4) ◽  
pp. 1131-1139 ◽  
Author(s):  
Ben L Gilby ◽  
Andrew D Olds ◽  
Christopher J Henderson ◽  
Nicholas L Ortodossi ◽  
Rod M Connolly ◽  
...  
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Fish Assemblages ◽  
Oyster Reef ◽  
Pivotal Role ◽  
Oyster Reefs ◽  
Total Abundance ◽  
Fish Recruitment ◽  
Abundance And Diversity ◽  
Species Specific

Abstract The seascape context of coastal ecosystems plays a pivotal role in shaping patterns in fish recruitment, abundance, and diversity. It might also be a principal determinant in structuring the recruitment of fish assemblages to restored habitats, but the trajectories of these relationships require further testing. In this study, we surveyed fish assemblages from 14 restored oyster reefs and 14 control sites in the Noosa River, Queensland, Australia, that differed in the presence or absence of seagrass within 500 m, over four periods using baited cameras. Fish assemblages at oyster reefs differed from those at control sites, with higher species richness (1.4 times) and more individuals of taxa that are harvested by fishers (1.8 times). The presence or absence of seagrass nearby affected the abundance of a key harvestable fish species (yellowfin bream Acanthopagrus australis) on oyster reefs, but not the overall composition of fish assemblages, species richness, or the total abundance of harvestable fishes overall. These findings highlight the importance of considering species-specific patterns in seascape utilization when selecting restoration sites and setting restoration goals, and suggest that the effects of restoration on fish assemblages might be optimized by focusing efforts in prime positions in coastal seascapes.

scholarly journals Tallgrass Prairie Responses to Management Practices and Disturbances: A Review

Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 300 ◽  
Author(s):  
Pradeep Wagle ◽  
Prasanna Gowda
Keyword(s):  
Species Richness ◽  
Soil Quality ◽  
Plant Species ◽  
Tallgrass Prairie ◽  
Management Practices ◽  
The United States ◽  
N Fertilization ◽  
Native Plant ◽  
The Impact

Adoption of better management practices is crucial to lessen the impact of anthropogenic disturbances on tallgrass prairie systems that contribute heavily for livestock production in several states of the United States. This article reviews the impacts of different common management practices and disturbances (e.g., fertilization, grazing, burning) and tallgrass prairie restoration on plant growth and development, plant species composition, water and nutrient cycles, and microbial activities in tallgrass prairie. Although nitrogen (N) fertilization increases aboveground productivity of prairie systems, several factors greatly influence the range of stimulation across sites. For example, response to N fertilization was more evident on frequently or annually burnt sites (N limiting) than infrequently burnt and unburnt sites (light limiting). Frequent burning increased density of C4 grasses and decreased plant species richness and diversity, while plant diversity was maximized under infrequent burning and grazing. Grazing increased diversity and richness of native plant species by reducing aboveground biomass of dominant grasses and increasing light availability for other species. Restored prairies showed lower levels of species richness and soil quality compared to native remnants. Infrequent burning, regular grazing, and additional inputs can promote species richness and soil quality in restored prairies. However, this literature review indicated that all prairie systems might not show similar responses to treatments as the response might be influenced by another treatment, timing of treatments, and duration of treatments (i.e., short-term vs. long-term). Thus, it is necessary to examine the long-term responses of tallgrass prairie systems to main and interacting effects of combination of management practices under diverse plant community and climatic conditions for a holistic assessment.

Nitrogen deposition and effects on European forests

2000 ◽  
Vol 8 (2) ◽  
pp. 65-93 ◽  
Author(s):  
J W Erisman ◽  
W de Vries
Keyword(s):  
Species Diversity ◽  
Nitrogen Deposition ◽  
Forest Ecosystems ◽  
N Deposition ◽  
Ground Vegetation ◽  
N Saturation ◽  
Input Output ◽  
Soil Response ◽  
Field Evidence ◽  
The Impact

Hypotheses about the impacts of elevated atmospheric deposition of nitrogen on the forest ecosystem include an increased sensitivity to natural stress, impacts on roots, reduced species diversity of the ground vegetation, reduced growth, and unbalanced nutritional status due to eutrophication and acidification. The impact of N deposition has gained in ecological importance during recent decades, in part due to the steady decline in S emissions. Results of throughfall and deposition measurements at 163 plots in Europe show that total deposition of S and N compounds ranged from 100 to 3000 mol ha–1 yr–1 in approximately 90% of the plots, but values up to 4000–8000 mol ha–1 yr–1 were also observed. Approximately 50% of the plots received N inputs, dominated by NH4, above 1000 mol ha–1 yr–1, which is a deposition level at which species diversity of the ground vegetation may be at risk. Results of input–output budgets for plots concentrated in Northern and Western Europe indicate that nitrate leaching starts to occur at throughfall inputs above 10 kg ha–1 yr–1, specifically in soils with C/N ratios in the humus layer below 25. Examples are given of field evidence for impacts of elevated N deposition, including elevated N contents in foliage and soil, Al release in soil response to increased nitrate concentrations, reduced shoot/root ratios, and a reduction in species diversity. Although knowledge about the response of forest ecosystems to N inputs has increased over the last decade, there is still a lack of information on the dynamics of N accumulation and related critical N loads in a range of environmental conditions. Furthermore, a European-wide perspective of N saturation in forest ecosystems is still lacking.Key words: nitrogen, deposition, input–output budgets, nitrogen status, forests, effects.

scholarly journals Assessment of environmental threats to the park’s forest ecosystems

2019 ◽  
Vol 25 ◽  
pp. 348-354
Author(s):  
N. V. Miroshnyk ◽  
O. V. Tertychna ◽  
I. K. Teslenko
Keyword(s):  
Forest Ecosystems ◽  
Negative Impact ◽  
Hazard Index ◽  
Urban Ecosystems ◽  
Urban Ecosystem ◽  
Spatial Spread ◽  
Environmental Threats ◽  
Mathematical Processing ◽  
The Impact

Aim. The aim is to assess the environmental threats to Park forest ecosystems and to study the possible links and the long-term consequences of their actions. Methods. Methods use of comparative analysis, classification, ranking of impacts, mathematical processing of data. Results. The main threats to Park forest ecosystems are formulated and evaluated. Deepened some of the methodological effects on criteria for assessment of threats. The classes of danger are defined, the General danger index of threats and correlation communications between groups and criteria of their assessment is calculated. The factors that have the most negative impact on the biodiversity of parks. Conclusions. In the conditions of urban ecosystems there is a strengthening and lengthening of the action of some threats and leveling of other types of impacts. The characteristics of the intensity of action, the time factor and the spatial spread of threats do not have a clear synchronization. The overall hazard index showed the dominance of the intensity and time of the impact of specific threats to the urban ecosystem. Keywords: anthropogenic impact, General hazard index, urban ecosystem, biodiversity.

scholarly journals On the general relationship between plant height and aboveground biomass of vegetation stands in contrasted ecosystems

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252080
Author(s):  
Raphaël Proulx
Keyword(s):  
Species Richness ◽  
Plant Communities ◽  
Unit Volume ◽  
Forest Ecosystems ◽  
Ecological Communities ◽  
Storage Efficiency ◽  
Causal Processes ◽  
Comparative Measure ◽  
Long Term Survey

Ecological communities are unique assemblages of species that coexist in consequence of multi-causal processes that have proven hard to generalize. One possible exception are processes that control the biomass packing of vegetation stands; the amount of aboveground standing biomass expressed per unit volume. In this paper, I investigated the empirical and geometric underpinnings of biomass packing in terrestrial plant communities. I support that biomass packing in nature peaks around 1 kg m-3 across contrasted contexts, ranging from grasslands to forest ecosystems. Using published experimental and long-term survey data, I show that expressing biomass per unit volume cancels the effects of air temperature, species richness and soil fertility on aboveground stocks, thus providing a general comparative measure of storage efficiency in plant communities.

scholarly journals The Impact of Changes in Species Richness and Species Replacement on Patterns of Taxonomic Homogenization in the Carpathian Forest Ecosystems

Forests ◽  
2015 ◽  
Vol 6 (12) ◽  
pp. 4391-4402 ◽  
Author(s):  
Tomasz Durak ◽  
Roma Durak ◽  
Ewa Węgrzyn ◽  
Konrad Leniowski
Keyword(s):  
Species Richness ◽  
Forest Ecosystems ◽  
Species Replacement ◽  
The Impact

scholarly journals Habitat complexity explains species-specific occupancy but not species richness in a Western Australian woodland

2008 ◽  
Vol 56 (2) ◽  
pp. 95 ◽  
Author(s):  
Jarrad A. Cousin ◽  
Ryan D. Phillips
Keyword(s):  
Species Richness ◽  
Western Australia ◽  
Habitat Complexity ◽  
Bird Species ◽  
Ground Vegetation ◽  
Additional Species ◽  
Bird Species Richness ◽  
Litter Cover ◽  
The Individual ◽  
Species Specific

Habitat complexity is an important factor governing species richness and habitat selection in birds. The present study examined this relationship in a large wandoo woodland in Western Australia. Habitat complexity (comprising canopy, shrub, ground vegetation, log and leaf litter cover) and bird species richness was recorded in 48 sites, each ~3 ha in size. We found no significant correlation of habitat complexity with species richness. We propose that the absence of such a relationship results from the resource-poor environment of the woodlands of south-western Australia. The relative scarcity of food resources results in a species richness threshold beyond which there are insufficient niches and resources to support additional species with increasing habitat complexity. Only two species exhibited significant associations with habitat complexity, with the western yellow robin (Eopsaltria griseogularis) occupying sites with higher habitat complexity, and the restless flycatcher (Myiagra inquieta) occupying sites with lower habitat complexity. Although some species may respond specifically to habitat complexity, management of avian biodiversity within Australian woodlands should take into account the potentially greater role that productivity and resource availability play in influencing species richness, rather than habitat complexity per se. Furthermore, the individual components comprising habitat complexity may be of equal importance in assessing relationship of species richness to overall habitat complexity.

scholarly journals Non-overlapping Distributions of Feral Sheep (Ovis aries) and Stout Iguanas (Cyclura pinguis) on Guana Island, British Virgin Islands

2012 ◽  
Vol 20 (1) ◽  
pp. 7-15
Author(s):  
Ben Skipper ◽  
Blake Grisham ◽  
Maria Kalyvaki ◽  
Kathleen McGaughey ◽  
Krista Mougey ◽  
...  
Keyword(s):  
Ground Level ◽  
Virgin Islands ◽  
Ovis Aries ◽  
Ground Vegetation ◽  
Vegetative Cover ◽  
Plant Abundance ◽  
British Virgin Islands ◽  
Introduced Herbivores ◽  
The Impact

Stout Iguanas (Cyclura pinguis) remain one of the most critically endangered reptiles in the world. Factors contributing to that status include habitat loss, predation by introduced species, and competition with introduced herbivores. On Guana Island, British Virgin Islands, the presence of feral sheep (Ovis aries) has been a hypothesized detriment to iguanas. Using motion sensitive cameras, we documented the distribution of feral sheep on Guana Island in 2010. We also quantified the impact of feral sheep on ground vegetation by comparing plant abundance at long term sheep exclosures and areas where sheep were absent to areas where sheep were present. Finally, we compared sheep distribution to iguana distribution on the island. The co-occurrence of sheep and Stout Iguanas was less than expected, indicating possible competition. Although we detected no difference in vegetative cover between areas where sheep were present and absent, the long-term exclosures showed that the exclusion of sheep allowed the abundance of many plant species to increase. Our data support the hypothesis that feral sheep are altering the abundance of ground-level vegetation and limiting iguana distribution on the island.

scholarly journals A two-decades (1988–2009) record of diatom fluxes in the Mauritanian coastal upwelling: Impact of low-frequency forcing and a two-step shift in the species composition

2020 ◽  
Author(s):  
Oscar E. Romero ◽  
Simon Ramondenc ◽  
Gerhard Fischer
Keyword(s):  
Coastal Waters ◽  
Temporal Dynamics ◽  
Meridional Overturning Circulation ◽  
Benthic Diatoms ◽  
Time Interval ◽  
Data Set ◽  
Specific Composition ◽  
Species Specific ◽  
The Impact

Abstract. Eastern Boundary Upwelling Ecosystems (EBUEs) are among the most productive marine regions in the world's oceans. Understanding the degree of interannual to decadal variability in the Mauritania upwelling system is key for the prediction of future changes of primary productivity and carbon sequestration in the Canary Current EBUE as well as in similar environments. A multiannual sediment trap experiment was conducted at the mooring site CBmeso (= 'Cape Blanc mesotrophic', ca. 20° N, ca. 20°40' W) in the high-productive Mauritanian coastal waters. Here, we present results on fluxes and the species-specific composition of the diatom assemblage for the time interval between March 1988 and May 2009. The temporal dynamics of diatom populations allows to propose three main diatom productivity/flux intervals: (i) early 1988–late 1996; (ii) 1997–1999, and (iii) early 2002–mid 2009. The impact of the Atlantic Multidecadal Oscillation appears to be an important forcing of the long-term dynamics of diatom population. The impact of cold (1988–1996) and warm AMO phases (2001–2009) is reflected by the outstanding shifts in species-specific composition. This AMO-impacted, long-term trend is interrupted by the occurrence of the strong 1997 ENSO. The extraordinary shift in the relative abundance of benthic diatoms in May 2002 suggests the strengthening of offshore advective transport within the uppermost layer of filament waters, and in the subsurface and in deeper and bottom‐near layers. It is hypothesized that the dominance of benthic diatoms was the response of the diatom community to the intensification of the slope and shelf poleward undercurrents. This dominance followed the intensification of the warm phase of AMO and the associated changes of the Atlantic Meridional Overturning Circulation. Transported valves (siliceous remains) from shallow coastal waters into the deeper bathypelagial should be considered for the calculation and model experiments of bathy- and pelagial nutrients budgets (especially Si), the burial of diatoms and the paleoenvironmental signal preserved in downcore sediments. Our 1988–2009 data set contributes to the distinction between climate-forced and intrinsic variability of populations of diatoms and will be especially helpful for establishing the scientific basis for forecasting and modelling future states of this ecosystem and its decadal changes.

scholarly journals FROM THE TORREY CANYON TO TODAY: A 50 YEAR RETROSPECTIVE OF RECOVERY FROM THE OIL SPILL AND INTERACTION WITH CLIMATE-DRIVEN FLUCTUATIONS ON CORNISH ROCKY SHORES

2017 ◽  
Vol 2017 (1) ◽  
pp. 74-103 ◽  
Author(s):  
Stephen J. Hawkins ◽  
Ally J. Evans ◽  
Jon Moore ◽  
Mark Whittington ◽  
Kathryn Pack ◽  
...  
Keyword(s):  
Rocky Shore ◽  
Oil Spills ◽  
Global Climate ◽  
Grazing Pressure ◽  
Spatial And Temporal Variation ◽  
Rocky Shores ◽  
Marine Biological Association ◽  
Key Species ◽  
The Impact

ABSTRACT The Torrey Canyon was wrecked in 1967 with 117,000 tons of crude oil on board. The Plymouth Laboratory of the Marine Biological Association (MBA) of the UK was mobilized to deal with this environmental catastrophe. Many of the rocky shores affected by the spill and unaffected control sites had been studied by staff from the MBA, with A.J. and E.C. Southward charting fluctuations of rocky shore fauna and flora from the early 1950s – particularly barnacles – in relation to climate. Thus a baseline existed to help judge recovery of rocky shores from the beached oil and application of toxic first generation dispersants. A reminder is given of the initial acute impacts of the oil and its treatment by dispersants, and the first ten years of observations on recovery of shore communities. Subsequent follow-up work in the 1980s and 1990s suggested recovery took up to 15 years on the shore (Porthleven) subject to the most severe dispersant application. In contrast, recovery occurred in 2–3 years at Godrevy, a site where dispersants were not applied due to concerns about the impact on seals. The dispersants killed the dominant grazer, limpets of the genus Patella, leading to massive subsequent colonisation by seaweeds. The resulting canopy of fucoid algae (“rockweed” or “wrack”) facilitated dense recruitment of limpets. These subsequently grazed the seaweeds down, before the starving limpets largely died off after migrating across the shore in search of food. This reduction in limpet numbers and grazing pressure then prompted a further bloom of algae. There was then a return to normal levels of spatial and temporal variation of key species of seaweeds and limpets fluctuations charted at Porthleven from the mid 1980s to 2016. Comparisons are made with other oil spills for which long-term recovery has been assessed. Lessons learnt from observations stretching back 60 years, both before and after the spill, for rocky shore monitoring are highlighted – especially the need for broad-scale and long-term monitoring to separate out local impacts (such as oil spills) from global climate-driven change.

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