Grassland species response to soil disturbance and nutrient enrichment on the Northern Tablelands of New South Wales

2005 ◽  
Vol 53 (6) ◽  
pp. 485 ◽  
Author(s):  
A. Chalmers ◽  
S. McIntyre ◽  
R. D. B. Whalley ◽  
N. Reid

An experiment was established in an area of long-grazed temperate grassland on the Northern Tablelands of New South Wales to investigate individual species response to mechanical soil disturbance and nutrient enrichment. Grazing was excluded for the duration of the experiment. The total species pool available in the experiment included 56 native and 24 exotic species recorded in the plots, as well as seven exotic species that were artificially introduced (i.e. sowing treatment). Eighteen months after treatment, total species richness was significantly lower under high soil disturbance (mean of 14.7 ± 0.85 species m–2) than under low (21.1 ± 0.67 species m–2) and moderately (21.7 ± 0.77 species m–2) disturbed conditions. Total species richness was not significantly affected by nutrient enrichment or sowing. Most of the annuals analysed were exotic and their relative cover increased with nutrient enrichment (Aira cupaniana Guss., Briza minor L. and Vulpia spp.), but was unresponsive to soil disturbance. Perennials showed varied responses, with the abundance of most decreasing with high soil disturbance and being unaffected by moderate soil disturbance levels. All four perennials favoured by high soil disturbance were exotic (Dactylis glomerata L., Lolium perenne L., Hypochaeris radicata L. and Sanguisorba minor Scop.); three of these were sown. Most perennials showed no significant response to nutrient enrichment, although the occurrence of a small number was either reduced (Aristida ramosa R.Br., A. warburgii Mez., H. radicata and S. minor) or increased (Carex inversa R.Br., D. glomerata, Fimbristylis dichotoma (L.) Vahl., Sporobolus creber De Nardi and Tricoryne elatior R.Br.). Most interactions (i.e. species response to one experimental factor depends on another experimental factor) occurred because few individuals survived on the severely soil-disturbed plots to respond to nutrient enrichment. However, in this particular grassland, the short-term response of most species to soil disturbance was independent of the level of nutrient enrichment.

2007 ◽  
Vol 144 (3) ◽  
pp. 465-486 ◽  
Author(s):  
CHRISTOPHER J. CLEAL

The South Wales Coalfield has the most complete Westphalian macrofloral record anywhere on the Variscan Foreland or adjacent basins, with 135 biodiversity-meaningful morphospecies having been recognized. All of the standard macrofloral biozones of the Westphalian Stage have been recognized, although a detailed comparison with the Central Pennines Coalfields has indicated some discrepancies in the relative positions of the biozonal boundaries. Total Species Richness progressively increases through the Langsettian Substage, and then remains relatively stable through most of the Duckmantian and Bolsovian substages. There is a distinct reduction in Total Species Richness towards the top of the Bolsovian Substage, but this partially recovers in the middle Asturian Substage with the appearance of a range of marattialean ferns, and medullosalean and callistophytaleans pteridosperms. There is no evidence of any significant drop in Total Species Richness towards the top of the succession, indicating that conditions at this time were relatively stable. The change from coastal floodplain to alluvial braidplain conditions in middle Bolsovian times correlates with a marked increase in the proportion of medullosalean remains being preserved in the adpression record, reflecting an expansion of the clastic-substrate habitats.


1994 ◽  
Vol 1 (3) ◽  
pp. 177 ◽  
Author(s):  
A. O. Nicholls

The measurement of diversity at the landscape scale is likely to suffer from many of the limitations that plague other measures of species diversity; there is little agreement as to how to calculate or interpret the measure or index. A recent addition to the suite of diversity measures is that of Scheiner's "mosaic diversity". In an attempt to accept Scheiner's challenge that "explorations of mosaic diversity among diverse landscapes ... will lead to new insights into the processes responsible for assembling species into communities" mosaic diversity has been calculated for 119 transects that sample the forests of the mid-north coast of New South Wales. Each transect is composed of five quadrats placed to encompass the variation in canopy floristic composition from xeric exposed slopes to mesic gullies. This paper looks at the environmental and spatial pattern of mosaic diversity. In addition I explore the relationship between mosaic diversity and other more readily grasped measures of diversity. Although very variable, Scheiner's mosaic diversity measure is shown to be weakly correlated with mean annual rainfall and mean annual temperature. In addition there is a weak trend in increasing mosaic diversity from the tablelands to the coast together with a trend of increase from south to north. Mosaic diversity did show a significant correlation with average species richness per quadrat within a transect but not with total species richness recorded on the transect nor with the number of alliances sampled by the five quadrats. The utility of this diversity measure to ecology remains unanswered by this study but the demonstration of weak relationships with both environmental and spatial variables given the small (5) sample size compared to that recommended (30+) suggests that further work is warranted.


2008 ◽  
Vol 38 (7) ◽  
pp. 1807-1816 ◽  
Author(s):  
Björn Nordén ◽  
Frank Götmark ◽  
Martin Ryberg ◽  
Heidi Paltto ◽  
Johan Allmér

Partial cutting is increasingly applied in European temperate oak-dominated forests for biofuel harvesting, and to counteract succession in protected stands. Effects on biodiversity of these measures need to be carefully evaluated, and species-rich but neglected taxa such as fungi should be considered. We studied the effects of partial cutting on fungal fruiting bodies on woody debris. In 21 closed canopy forests rich in large oaks in Sweden, on average 25%–30% of the basal area was cut. Fruiting bodies were counted and some were collected in treated and control plots before and after treatment. We found 334 basidiomycete and 47 ascomycete species. Species richness of basidiomycetes declined significantly more in treated plots (on average 26%) than in control plots (on average 13%) between seasons. Species richness of ascomycetes increased by 17% in control plots and decreased by 2% in treated plots. Total species richness was significantly reduced on fine woody debris (1–10 cm in diameter), but not on coarse woody debris (>10 cm). Overall species composition did not change significantly as a result of partial cutting, but red-listed species tended to decrease more in treated plots. We suggest that approximately 30% of the stands should not be thinned, and dead stems and fallen branches should not be removed, to favor saproxylic fungi and their associated fauna.


2007 ◽  
Vol 50 (6) ◽  
pp. 1033-1042 ◽  
Author(s):  
Yzel Rondon Súarez ◽  
Sabrina Bigatão Valério ◽  
Karina Keyla Tondado ◽  
Alexandro Cezar Florentino ◽  
Thiago Rota Alves Felipe ◽  
...  

The influence of spatial, temporal and environmental factors on fish species diversity in headwater streams in Paraguay and Paraná basins, Brazil was examined. A total of 4,605 individuals were sampled, distributed in 60 species. The sampled streams in Paraná basin presented a larger total species richness (42) than Paraguay streams (40). However the estimated richness was larger in Paraguay basin (53) than Paraná streams (50). The streams of Paraná basin had a greater mean species richness and evenness, while more individuals per sample were found in the Paraguay basin. Difference between the sub-basins were found in the Paraguay basin, while for the basin of Paraná, richness and evenness vary significantly between the sub-basins, but the number of individuals varied seasonally. The most important environmental factors to species diversity and abundance were altitude, water temperature, stream width and stream depth for both the basins.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tanya A. Petruff ◽  
Joseph R. McMillan ◽  
John J. Shepard ◽  
Theodore G. Andreadis ◽  
Philip M. Armstrong

Abstract Historical declines in multiple insect taxa have been documented across the globe in relation to landscape-level changes in land use and climate. However, declines have either not been universally observed in all regions or examined for all species. Because mosquitoes are insects of public health importance, we analyzed a longitudinal mosquito surveillance data set from Connecticut (CT), United States (U.S.) from 2001 to 2019 to identify changes in mosquito community composition over time. We first analyzed annual site-level collections and metrics of mosquito community composition with generalized linear/additive mixed effects models; we also examined annual species-level collections using the same tools. We then examined correlations between statewide collections and weather variables as well as site-level collections and land cover classifications. We found evidence that the average trap night collection of mosquitoes has increased by ~ 60% and statewide species richness has increased by ~ 10% since 2001. Total species richness was highest in the southern portion of CT, likely due to the northward range expansion of multiple species within the Aedes, Anopheles, Culex, and Psorophora genera. How the expansion of mosquito populations in the northeast U.S. will alter mosquito-borne pathogen transmission in the region will require further investigation.


1974 ◽  
Vol 14 (71) ◽  
pp. 790 ◽  
Author(s):  
JV Lovett ◽  
EM Matheson

In field experiments conducted over three years at Armidale, New South Wales, the total winter forage production by barley, oats, wheat and rye was similar. However, barley and rye tended to outyield wheat and oats at early harvests, the reverse applying at late harvests. It is suggested that these characteristics of the cereals could be exploited to meet specific seasonal requirements for dry matter production more effectively than is possible with a single species. Response to high seeding rates in forage production was similar in all cereals and was confined to a late sowing. Significant differences in in vitro digestibility over the winter period were recorded and differences were also apparent in subsequent grain yield.


2006 ◽  
Vol 12 (2) ◽  
pp. 140 ◽  
Author(s):  
Michael F. Braby ◽  
Ted D. Edwards

Thirty-three species of butterflies are recorded from the Griffith district in the semi-arid zone of inland southern New South Wales. The butterfly community comprises the following structure: 19 species (58%) are resident; 7 (21 %) are regular immigrants; 2 (6%) are irregular immigrants; 5 (15%) are vagrants. Except for a few migratory species, most occur in relatively low abundance. Lack of similar studies elsewhere in western New South Wales precludes generalizations regarding the species richness, composition and structure of semi-arid butterfly communities. Comparison of the butterfly fauna with that from five other inland regions on the slopes and foothills of the Great Diving Range, revealed that the Griffith district is most similar in species richness and composition to that of Deniliquin and to a lesser extent Wagga Wagga and Cowra in the south, than with two regions in the higher summer rainfall area of the north of the State (Coonabarabran-Mendooran, Narrabri-Bellata). Overall, the butterfly fauna of inland New South Wales (total of 73 species, of which 49 occur in the southern regions) is depauperate compared with that recorded from the coastal/subcoastal areas east of the Great Dividing Range. Attention is drawn to the conservation significance of several vegetation types and habitat remnants in the Griffith district. Much of the native vegetation in the district has been extensively modified since European settlement due to excessive clearing for agriculture, resulting in a highly fragmented landscape for the conservation of native flora and fauna. With the exception of the lycaenid Candalides hyacinthinus Simplex, which is considered threatened locally, there is a general absence of narrow range endemic butterflies associated with mallee-heathland or mallee-woodland, possibly as a result of widespread land clearing practices of mallee vegetation in the past.


Soil Research ◽  
2000 ◽  
Vol 38 (1) ◽  
pp. 129 ◽  
Author(s):  
Erry Purnomo ◽  
A. S. Black ◽  
C. J. Smith ◽  
M. K. Conyers

To test the hypothesis that net nitrogen (N) mineralisation is concentrated in the surface few centimetres following minimal soil disturbance for crop establishment, mineralisation was measured during the growth of wheat. The soil was a Red Kandosol located in southern New South Wales. Mineralisation was estimated usingin situ incubations inside capped PVC tubes, which were sampled every 3 weeks. Soil from the tubes was sampled at depth intervals of 2 cm to a depth of 10 cm and at 5-cm intervals from 10 to 20 cm. The results showed that net N mineralisation decreased with depth to 20 cm. Over the season, an average of 32% of the N mineralised in the top 20 cm of soil originated from the 0–2 cm layer, 72% was from the 0–6 cm layer, and only 13% was from soil below 10 cm. The decrease in N mineralisation with soil depth was highly correlated with decreases in the organic carbon (r2 = 0.84, P < 0.05) and total N (r2 = 0.83, P < 0.05) concentration. The soil's N-supplying ability is concentrated near the surface where it is susceptible to erosional loss. The N supply may also be inhibited by temperature and moisture extremes, which are common in the surface few centimetres of soil where mineralisation was concentrated. The PVC enclosures created artefacts in soil temperature and moisture, although it is argued that the effects on net N mineralisation were small in most sampling periods.


2019 ◽  
Vol 88 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Bernhard A. Huber ◽  
Anne Chao

Ratio-like approaches for estimating global species richness have been criticised for their unjustified extrapolation from regional to global patterns. Here we explore the use of cumulative percentages of ‘new’ (i.e., not formally described) species over large geographic areas (‘megatransects’) as a means to overcome this problem. In addition, we take into account undetected species and illustrate these combined methods by applying them to a family of spiders (Pholcidae) that currently contains some 1,700 described species. The raw global cumulative percentage of new species (‘new’ as of the end of 2008, when 1,001 species were formally described) is 75.1%, and is relatively constant across large biogeographic regions. Undetected species are estimated using the Chao2 estimator based on species incidence data (date by species and locality by species matrices). The estimated percentage of new species based on the date by species matrices is 76.0% with an estimated standard error (s.e.) of 2.6%. This leads to an estimated global species richness of about 4,200 with a 95% confidence interval of (3,300, 5,000). The corresponding values based on locality by species matrices are 84.2% (s.e. 3.0%) and 6,300 with a 95% confidence interval of (4,000, 8,600). Our results suggest that the currently known 1,700 species of Pholcidae may represent no more than about 25–40% of the total species richness. The impact of further biasing factors like geography, species size and distribution, cryptic species, and model assumptions needs to be explored.


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